xref: /openbmc/qemu/gdbstub/gdbstub.c (revision ddd17313)
1 /*
2  * gdb server stub
3  *
4  * This implements a subset of the remote protocol as described in:
5  *
6  *   https://sourceware.org/gdb/onlinedocs/gdb/Remote-Protocol.html
7  *
8  * Copyright (c) 2003-2005 Fabrice Bellard
9  *
10  * This library is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2 of the License, or (at your option) any later version.
14  *
15  * This library is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
22  *
23  * SPDX-License-Identifier: LGPL-2.0+
24  */
25 
26 #include "qemu/osdep.h"
27 #include "qemu/ctype.h"
28 #include "qemu/cutils.h"
29 #include "qemu/module.h"
30 #include "qemu/error-report.h"
31 #include "trace.h"
32 #include "exec/gdbstub.h"
33 #include "gdbstub/commands.h"
34 #include "gdbstub/syscalls.h"
35 #ifdef CONFIG_USER_ONLY
36 #include "accel/tcg/vcpu-state.h"
37 #include "gdbstub/user.h"
38 #else
39 #include "hw/cpu/cluster.h"
40 #include "hw/boards.h"
41 #endif
42 #include "hw/core/cpu.h"
43 
44 #include "sysemu/hw_accel.h"
45 #include "sysemu/runstate.h"
46 #include "exec/replay-core.h"
47 #include "exec/hwaddr.h"
48 
49 #include "internals.h"
50 
51 typedef struct GDBRegisterState {
52     int base_reg;
53     gdb_get_reg_cb get_reg;
54     gdb_set_reg_cb set_reg;
55     const GDBFeature *feature;
56 } GDBRegisterState;
57 
58 GDBState gdbserver_state;
59 
60 void gdb_init_gdbserver_state(void)
61 {
62     g_assert(!gdbserver_state.init);
63     memset(&gdbserver_state, 0, sizeof(GDBState));
64     gdbserver_state.init = true;
65     gdbserver_state.str_buf = g_string_new(NULL);
66     gdbserver_state.mem_buf = g_byte_array_sized_new(MAX_PACKET_LENGTH);
67     gdbserver_state.last_packet = g_byte_array_sized_new(MAX_PACKET_LENGTH + 4);
68 
69     /*
70      * What single-step modes are supported is accelerator dependent.
71      * By default try to use no IRQs and no timers while single
72      * stepping so as to make single stepping like a typical ICE HW step.
73      */
74     gdbserver_state.supported_sstep_flags = accel_supported_gdbstub_sstep_flags();
75     gdbserver_state.sstep_flags = SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER;
76     gdbserver_state.sstep_flags &= gdbserver_state.supported_sstep_flags;
77 }
78 
79 /* writes 2*len+1 bytes in buf */
80 void gdb_memtohex(GString *buf, const uint8_t *mem, int len)
81 {
82     int i, c;
83     for(i = 0; i < len; i++) {
84         c = mem[i];
85         g_string_append_c(buf, tohex(c >> 4));
86         g_string_append_c(buf, tohex(c & 0xf));
87     }
88     g_string_append_c(buf, '\0');
89 }
90 
91 void gdb_hextomem(GByteArray *mem, const char *buf, int len)
92 {
93     int i;
94 
95     for(i = 0; i < len; i++) {
96         guint8 byte = fromhex(buf[0]) << 4 | fromhex(buf[1]);
97         g_byte_array_append(mem, &byte, 1);
98         buf += 2;
99     }
100 }
101 
102 static void hexdump(const char *buf, int len,
103                     void (*trace_fn)(size_t ofs, char const *text))
104 {
105     char line_buffer[3 * 16 + 4 + 16 + 1];
106 
107     size_t i;
108     for (i = 0; i < len || (i & 0xF); ++i) {
109         size_t byte_ofs = i & 15;
110 
111         if (byte_ofs == 0) {
112             memset(line_buffer, ' ', 3 * 16 + 4 + 16);
113             line_buffer[3 * 16 + 4 + 16] = 0;
114         }
115 
116         size_t col_group = (i >> 2) & 3;
117         size_t hex_col = byte_ofs * 3 + col_group;
118         size_t txt_col = 3 * 16 + 4 + byte_ofs;
119 
120         if (i < len) {
121             char value = buf[i];
122 
123             line_buffer[hex_col + 0] = tohex((value >> 4) & 0xF);
124             line_buffer[hex_col + 1] = tohex((value >> 0) & 0xF);
125             line_buffer[txt_col + 0] = (value >= ' ' && value < 127)
126                     ? value
127                     : '.';
128         }
129 
130         if (byte_ofs == 0xF)
131             trace_fn(i & -16, line_buffer);
132     }
133 }
134 
135 /* return -1 if error, 0 if OK */
136 int gdb_put_packet_binary(const char *buf, int len, bool dump)
137 {
138     int csum, i;
139     uint8_t footer[3];
140 
141     if (dump && trace_event_get_state_backends(TRACE_GDBSTUB_IO_BINARYREPLY)) {
142         hexdump(buf, len, trace_gdbstub_io_binaryreply);
143     }
144 
145     for(;;) {
146         g_byte_array_set_size(gdbserver_state.last_packet, 0);
147         g_byte_array_append(gdbserver_state.last_packet,
148                             (const uint8_t *) "$", 1);
149         g_byte_array_append(gdbserver_state.last_packet,
150                             (const uint8_t *) buf, len);
151         csum = 0;
152         for(i = 0; i < len; i++) {
153             csum += buf[i];
154         }
155         footer[0] = '#';
156         footer[1] = tohex((csum >> 4) & 0xf);
157         footer[2] = tohex((csum) & 0xf);
158         g_byte_array_append(gdbserver_state.last_packet, footer, 3);
159 
160         gdb_put_buffer(gdbserver_state.last_packet->data,
161                    gdbserver_state.last_packet->len);
162 
163         if (gdb_got_immediate_ack()) {
164             break;
165         }
166     }
167     return 0;
168 }
169 
170 /* return -1 if error, 0 if OK */
171 int gdb_put_packet(const char *buf)
172 {
173     trace_gdbstub_io_reply(buf);
174 
175     return gdb_put_packet_binary(buf, strlen(buf), false);
176 }
177 
178 void gdb_put_strbuf(void)
179 {
180     gdb_put_packet(gdbserver_state.str_buf->str);
181 }
182 
183 /* Encode data using the encoding for 'x' packets.  */
184 void gdb_memtox(GString *buf, const char *mem, int len)
185 {
186     char c;
187 
188     while (len--) {
189         c = *(mem++);
190         switch (c) {
191         case '#': case '$': case '*': case '}':
192             g_string_append_c(buf, '}');
193             g_string_append_c(buf, c ^ 0x20);
194             break;
195         default:
196             g_string_append_c(buf, c);
197             break;
198         }
199     }
200 }
201 
202 static uint32_t gdb_get_cpu_pid(CPUState *cpu)
203 {
204 #ifdef CONFIG_USER_ONLY
205     return getpid();
206 #else
207     if (cpu->cluster_index == UNASSIGNED_CLUSTER_INDEX) {
208         /* Return the default process' PID */
209         int index = gdbserver_state.process_num - 1;
210         return gdbserver_state.processes[index].pid;
211     }
212     return cpu->cluster_index + 1;
213 #endif
214 }
215 
216 GDBProcess *gdb_get_process(uint32_t pid)
217 {
218     int i;
219 
220     if (!pid) {
221         /* 0 means any process, we take the first one */
222         return &gdbserver_state.processes[0];
223     }
224 
225     for (i = 0; i < gdbserver_state.process_num; i++) {
226         if (gdbserver_state.processes[i].pid == pid) {
227             return &gdbserver_state.processes[i];
228         }
229     }
230 
231     return NULL;
232 }
233 
234 static GDBProcess *gdb_get_cpu_process(CPUState *cpu)
235 {
236     return gdb_get_process(gdb_get_cpu_pid(cpu));
237 }
238 
239 static CPUState *find_cpu(uint32_t thread_id)
240 {
241     CPUState *cpu;
242 
243     CPU_FOREACH(cpu) {
244         if (gdb_get_cpu_index(cpu) == thread_id) {
245             return cpu;
246         }
247     }
248 
249     return NULL;
250 }
251 
252 CPUState *gdb_get_first_cpu_in_process(GDBProcess *process)
253 {
254     CPUState *cpu;
255 
256     CPU_FOREACH(cpu) {
257         if (gdb_get_cpu_pid(cpu) == process->pid) {
258             return cpu;
259         }
260     }
261 
262     return NULL;
263 }
264 
265 static CPUState *gdb_next_cpu_in_process(CPUState *cpu)
266 {
267     uint32_t pid = gdb_get_cpu_pid(cpu);
268     cpu = CPU_NEXT(cpu);
269 
270     while (cpu) {
271         if (gdb_get_cpu_pid(cpu) == pid) {
272             break;
273         }
274 
275         cpu = CPU_NEXT(cpu);
276     }
277 
278     return cpu;
279 }
280 
281 /* Return the cpu following @cpu, while ignoring unattached processes. */
282 static CPUState *gdb_next_attached_cpu(CPUState *cpu)
283 {
284     cpu = CPU_NEXT(cpu);
285 
286     while (cpu) {
287         if (gdb_get_cpu_process(cpu)->attached) {
288             break;
289         }
290 
291         cpu = CPU_NEXT(cpu);
292     }
293 
294     return cpu;
295 }
296 
297 /* Return the first attached cpu */
298 CPUState *gdb_first_attached_cpu(void)
299 {
300     CPUState *cpu = first_cpu;
301     GDBProcess *process = gdb_get_cpu_process(cpu);
302 
303     if (!process->attached) {
304         return gdb_next_attached_cpu(cpu);
305     }
306 
307     return cpu;
308 }
309 
310 static CPUState *gdb_get_cpu(uint32_t pid, uint32_t tid)
311 {
312     GDBProcess *process;
313     CPUState *cpu;
314 
315     if (!pid && !tid) {
316         /* 0 means any process/thread, we take the first attached one */
317         return gdb_first_attached_cpu();
318     } else if (pid && !tid) {
319         /* any thread in a specific process */
320         process = gdb_get_process(pid);
321 
322         if (process == NULL) {
323             return NULL;
324         }
325 
326         if (!process->attached) {
327             return NULL;
328         }
329 
330         return gdb_get_first_cpu_in_process(process);
331     } else {
332         /* a specific thread */
333         cpu = find_cpu(tid);
334 
335         if (cpu == NULL) {
336             return NULL;
337         }
338 
339         process = gdb_get_cpu_process(cpu);
340 
341         if (pid && process->pid != pid) {
342             return NULL;
343         }
344 
345         if (!process->attached) {
346             return NULL;
347         }
348 
349         return cpu;
350     }
351 }
352 
353 static const char *get_feature_xml(const char *p, const char **newp,
354                                    GDBProcess *process)
355 {
356     CPUState *cpu = gdb_get_first_cpu_in_process(process);
357     CPUClass *cc = CPU_GET_CLASS(cpu);
358     GDBRegisterState *r;
359     size_t len;
360 
361     /*
362      * qXfer:features:read:ANNEX:OFFSET,LENGTH'
363      *                     ^p    ^newp
364      */
365     char *term = strchr(p, ':');
366     *newp = term + 1;
367     len = term - p;
368 
369     /* Is it the main target xml? */
370     if (strncmp(p, "target.xml", len) == 0) {
371         if (!process->target_xml) {
372             g_autoptr(GPtrArray) xml = g_ptr_array_new_with_free_func(g_free);
373 
374             g_ptr_array_add(
375                 xml,
376                 g_strdup("<?xml version=\"1.0\"?>"
377                          "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">"
378                          "<target>"));
379 
380             if (cc->gdb_arch_name) {
381                 g_ptr_array_add(
382                     xml,
383                     g_markup_printf_escaped("<architecture>%s</architecture>",
384                                             cc->gdb_arch_name(cpu)));
385             }
386             for (guint i = 0; i < cpu->gdb_regs->len; i++) {
387                 r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
388                 g_ptr_array_add(
389                     xml,
390                     g_markup_printf_escaped("<xi:include href=\"%s\"/>",
391                                             r->feature->xmlname));
392             }
393             g_ptr_array_add(xml, g_strdup("</target>"));
394             g_ptr_array_add(xml, NULL);
395 
396             process->target_xml = g_strjoinv(NULL, (void *)xml->pdata);
397         }
398         return process->target_xml;
399     }
400     /* Is it one of the features? */
401     for (guint i = 0; i < cpu->gdb_regs->len; i++) {
402         r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
403         if (strncmp(p, r->feature->xmlname, len) == 0) {
404             return r->feature->xml;
405         }
406     }
407 
408     /* failed */
409     return NULL;
410 }
411 
412 void gdb_feature_builder_init(GDBFeatureBuilder *builder, GDBFeature *feature,
413                               const char *name, const char *xmlname,
414                               int base_reg)
415 {
416     char *header = g_markup_printf_escaped(
417         "<?xml version=\"1.0\"?>"
418         "<!DOCTYPE feature SYSTEM \"gdb-target.dtd\">"
419         "<feature name=\"%s\">",
420         name);
421 
422     builder->feature = feature;
423     builder->xml = g_ptr_array_new();
424     g_ptr_array_add(builder->xml, header);
425     builder->regs = g_ptr_array_new();
426     builder->base_reg = base_reg;
427     feature->xmlname = xmlname;
428     feature->name = name;
429 }
430 
431 void gdb_feature_builder_append_tag(const GDBFeatureBuilder *builder,
432                                     const char *format, ...)
433 {
434     va_list ap;
435     va_start(ap, format);
436     g_ptr_array_add(builder->xml, g_markup_vprintf_escaped(format, ap));
437     va_end(ap);
438 }
439 
440 void gdb_feature_builder_append_reg(const GDBFeatureBuilder *builder,
441                                     const char *name,
442                                     int bitsize,
443                                     int regnum,
444                                     const char *type,
445                                     const char *group)
446 {
447     if (builder->regs->len <= regnum) {
448         g_ptr_array_set_size(builder->regs, regnum + 1);
449     }
450 
451     builder->regs->pdata[regnum] = (gpointer *)name;
452 
453     if (group) {
454         gdb_feature_builder_append_tag(
455             builder,
456             "<reg name=\"%s\" bitsize=\"%d\" regnum=\"%d\" type=\"%s\" group=\"%s\"/>",
457             name, bitsize, builder->base_reg + regnum, type, group);
458     } else {
459         gdb_feature_builder_append_tag(
460             builder,
461             "<reg name=\"%s\" bitsize=\"%d\" regnum=\"%d\" type=\"%s\"/>",
462             name, bitsize, builder->base_reg + regnum, type);
463     }
464 }
465 
466 void gdb_feature_builder_end(const GDBFeatureBuilder *builder)
467 {
468     g_ptr_array_add(builder->xml, (void *)"</feature>");
469     g_ptr_array_add(builder->xml, NULL);
470 
471     builder->feature->xml = g_strjoinv(NULL, (void *)builder->xml->pdata);
472 
473     for (guint i = 0; i < builder->xml->len - 2; i++) {
474         g_free(g_ptr_array_index(builder->xml, i));
475     }
476 
477     g_ptr_array_free(builder->xml, TRUE);
478 
479     builder->feature->num_regs = builder->regs->len;
480     builder->feature->regs = (void *)g_ptr_array_free(builder->regs, FALSE);
481 }
482 
483 const GDBFeature *gdb_find_static_feature(const char *xmlname)
484 {
485     const GDBFeature *feature;
486 
487     for (feature = gdb_static_features; feature->xmlname; feature++) {
488         if (!strcmp(feature->xmlname, xmlname)) {
489             return feature;
490         }
491     }
492 
493     g_assert_not_reached();
494 }
495 
496 GArray *gdb_get_register_list(CPUState *cpu)
497 {
498     GArray *results = g_array_new(true, true, sizeof(GDBRegDesc));
499 
500     /* registers are only available once the CPU is initialised */
501     if (!cpu->gdb_regs) {
502         return results;
503     }
504 
505     for (int f = 0; f < cpu->gdb_regs->len; f++) {
506         GDBRegisterState *r = &g_array_index(cpu->gdb_regs, GDBRegisterState, f);
507         for (int i = 0; i < r->feature->num_regs; i++) {
508             const char *name = r->feature->regs[i];
509             GDBRegDesc desc = {
510                 r->base_reg + i,
511                 name,
512                 r->feature->name
513             };
514             g_array_append_val(results, desc);
515         }
516     }
517 
518     return results;
519 }
520 
521 int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
522 {
523     CPUClass *cc = CPU_GET_CLASS(cpu);
524     GDBRegisterState *r;
525 
526     if (reg < cc->gdb_num_core_regs) {
527         return cc->gdb_read_register(cpu, buf, reg);
528     }
529 
530     for (guint i = 0; i < cpu->gdb_regs->len; i++) {
531         r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
532         if (r->base_reg <= reg && reg < r->base_reg + r->feature->num_regs) {
533             return r->get_reg(cpu, buf, reg - r->base_reg);
534         }
535     }
536     return 0;
537 }
538 
539 static int gdb_write_register(CPUState *cpu, uint8_t *mem_buf, int reg)
540 {
541     CPUClass *cc = CPU_GET_CLASS(cpu);
542     GDBRegisterState *r;
543 
544     if (reg < cc->gdb_num_core_regs) {
545         return cc->gdb_write_register(cpu, mem_buf, reg);
546     }
547 
548     for (guint i = 0; i < cpu->gdb_regs->len; i++) {
549         r =  &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
550         if (r->base_reg <= reg && reg < r->base_reg + r->feature->num_regs) {
551             return r->set_reg(cpu, mem_buf, reg - r->base_reg);
552         }
553     }
554     return 0;
555 }
556 
557 static void gdb_register_feature(CPUState *cpu, int base_reg,
558                                  gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
559                                  const GDBFeature *feature)
560 {
561     GDBRegisterState s = {
562         .base_reg = base_reg,
563         .get_reg = get_reg,
564         .set_reg = set_reg,
565         .feature = feature
566     };
567 
568     g_array_append_val(cpu->gdb_regs, s);
569 }
570 
571 void gdb_init_cpu(CPUState *cpu)
572 {
573     CPUClass *cc = CPU_GET_CLASS(cpu);
574     const GDBFeature *feature;
575 
576     cpu->gdb_regs = g_array_new(false, false, sizeof(GDBRegisterState));
577 
578     if (cc->gdb_core_xml_file) {
579         feature = gdb_find_static_feature(cc->gdb_core_xml_file);
580         gdb_register_feature(cpu, 0,
581                              cc->gdb_read_register, cc->gdb_write_register,
582                              feature);
583         cpu->gdb_num_regs = cpu->gdb_num_g_regs = feature->num_regs;
584     }
585 
586     if (cc->gdb_num_core_regs) {
587         cpu->gdb_num_regs = cpu->gdb_num_g_regs = cc->gdb_num_core_regs;
588     }
589 }
590 
591 void gdb_register_coprocessor(CPUState *cpu,
592                               gdb_get_reg_cb get_reg, gdb_set_reg_cb set_reg,
593                               const GDBFeature *feature, int g_pos)
594 {
595     GDBRegisterState *s;
596     guint i;
597     int base_reg = cpu->gdb_num_regs;
598 
599     for (i = 0; i < cpu->gdb_regs->len; i++) {
600         /* Check for duplicates.  */
601         s = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
602         if (s->feature == feature) {
603             return;
604         }
605     }
606 
607     gdb_register_feature(cpu, base_reg, get_reg, set_reg, feature);
608 
609     /* Add to end of list.  */
610     cpu->gdb_num_regs += feature->num_regs;
611     if (g_pos) {
612         if (g_pos != base_reg) {
613             error_report("Error: Bad gdb register numbering for '%s', "
614                          "expected %d got %d", feature->xml, g_pos, base_reg);
615         } else {
616             cpu->gdb_num_g_regs = cpu->gdb_num_regs;
617         }
618     }
619 }
620 
621 static void gdb_process_breakpoint_remove_all(GDBProcess *p)
622 {
623     CPUState *cpu = gdb_get_first_cpu_in_process(p);
624 
625     while (cpu) {
626         gdb_breakpoint_remove_all(cpu);
627         cpu = gdb_next_cpu_in_process(cpu);
628     }
629 }
630 
631 
632 static void gdb_set_cpu_pc(vaddr pc)
633 {
634     CPUState *cpu = gdbserver_state.c_cpu;
635 
636     cpu_synchronize_state(cpu);
637     cpu_set_pc(cpu, pc);
638 }
639 
640 void gdb_append_thread_id(CPUState *cpu, GString *buf)
641 {
642     if (gdbserver_state.multiprocess) {
643         g_string_append_printf(buf, "p%02x.%02x",
644                                gdb_get_cpu_pid(cpu), gdb_get_cpu_index(cpu));
645     } else {
646         g_string_append_printf(buf, "%02x", gdb_get_cpu_index(cpu));
647     }
648 }
649 
650 static GDBThreadIdKind read_thread_id(const char *buf, const char **end_buf,
651                                       uint32_t *pid, uint32_t *tid)
652 {
653     unsigned long p, t;
654     int ret;
655 
656     if (*buf == 'p') {
657         buf++;
658         ret = qemu_strtoul(buf, &buf, 16, &p);
659 
660         if (ret) {
661             return GDB_READ_THREAD_ERR;
662         }
663 
664         /* Skip '.' */
665         buf++;
666     } else {
667         p = 0;
668     }
669 
670     ret = qemu_strtoul(buf, &buf, 16, &t);
671 
672     if (ret) {
673         return GDB_READ_THREAD_ERR;
674     }
675 
676     *end_buf = buf;
677 
678     if (p == -1) {
679         return GDB_ALL_PROCESSES;
680     }
681 
682     if (pid) {
683         *pid = p;
684     }
685 
686     if (t == -1) {
687         return GDB_ALL_THREADS;
688     }
689 
690     if (tid) {
691         *tid = t;
692     }
693 
694     return GDB_ONE_THREAD;
695 }
696 
697 /**
698  * gdb_handle_vcont - Parses and handles a vCont packet.
699  * returns -ENOTSUP if a command is unsupported, -EINVAL or -ERANGE if there is
700  *         a format error, 0 on success.
701  */
702 static int gdb_handle_vcont(const char *p)
703 {
704     int res, signal = 0;
705     char cur_action;
706     unsigned long tmp;
707     uint32_t pid, tid;
708     GDBProcess *process;
709     CPUState *cpu;
710     GDBThreadIdKind kind;
711     unsigned int max_cpus = gdb_get_max_cpus();
712     /* uninitialised CPUs stay 0 */
713     g_autofree char *newstates = g_new0(char, max_cpus);
714 
715     /* mark valid CPUs with 1 */
716     CPU_FOREACH(cpu) {
717         newstates[cpu->cpu_index] = 1;
718     }
719 
720     /*
721      * res keeps track of what error we are returning, with -ENOTSUP meaning
722      * that the command is unknown or unsupported, thus returning an empty
723      * packet, while -EINVAL and -ERANGE cause an E22 packet, due to invalid,
724      *  or incorrect parameters passed.
725      */
726     res = 0;
727 
728     /*
729      * target_count and last_target keep track of how many CPUs we are going to
730      * step or resume, and a pointer to the state structure of one of them,
731      * respectively
732      */
733     int target_count = 0;
734     CPUState *last_target = NULL;
735 
736     while (*p) {
737         if (*p++ != ';') {
738             return -ENOTSUP;
739         }
740 
741         cur_action = *p++;
742         if (cur_action == 'C' || cur_action == 'S') {
743             cur_action = qemu_tolower(cur_action);
744             res = qemu_strtoul(p, &p, 16, &tmp);
745             if (res) {
746                 return res;
747             }
748             signal = gdb_signal_to_target(tmp);
749         } else if (cur_action != 'c' && cur_action != 's') {
750             /* unknown/invalid/unsupported command */
751             return -ENOTSUP;
752         }
753 
754         if (*p == '\0' || *p == ';') {
755             /*
756              * No thread specifier, action is on "all threads". The
757              * specification is unclear regarding the process to act on. We
758              * choose all processes.
759              */
760             kind = GDB_ALL_PROCESSES;
761         } else if (*p++ == ':') {
762             kind = read_thread_id(p, &p, &pid, &tid);
763         } else {
764             return -ENOTSUP;
765         }
766 
767         switch (kind) {
768         case GDB_READ_THREAD_ERR:
769             return -EINVAL;
770 
771         case GDB_ALL_PROCESSES:
772             cpu = gdb_first_attached_cpu();
773             while (cpu) {
774                 if (newstates[cpu->cpu_index] == 1) {
775                     newstates[cpu->cpu_index] = cur_action;
776 
777                     target_count++;
778                     last_target = cpu;
779                 }
780 
781                 cpu = gdb_next_attached_cpu(cpu);
782             }
783             break;
784 
785         case GDB_ALL_THREADS:
786             process = gdb_get_process(pid);
787 
788             if (!process->attached) {
789                 return -EINVAL;
790             }
791 
792             cpu = gdb_get_first_cpu_in_process(process);
793             while (cpu) {
794                 if (newstates[cpu->cpu_index] == 1) {
795                     newstates[cpu->cpu_index] = cur_action;
796 
797                     target_count++;
798                     last_target = cpu;
799                 }
800 
801                 cpu = gdb_next_cpu_in_process(cpu);
802             }
803             break;
804 
805         case GDB_ONE_THREAD:
806             cpu = gdb_get_cpu(pid, tid);
807 
808             /* invalid CPU/thread specified */
809             if (!cpu) {
810                 return -EINVAL;
811             }
812 
813             /* only use if no previous match occourred */
814             if (newstates[cpu->cpu_index] == 1) {
815                 newstates[cpu->cpu_index] = cur_action;
816 
817                 target_count++;
818                 last_target = cpu;
819             }
820             break;
821         }
822     }
823 
824     /*
825      * if we're about to resume a specific set of CPUs/threads, make it so that
826      * in case execution gets interrupted, we can send GDB a stop reply with a
827      * correct value. it doesn't really matter which CPU we tell GDB the signal
828      * happened in (VM pauses stop all of them anyway), so long as it is one of
829      * the ones we resumed/single stepped here.
830      */
831     if (target_count > 0) {
832         gdbserver_state.c_cpu = last_target;
833     }
834 
835     gdbserver_state.signal = signal;
836     gdb_continue_partial(newstates);
837     return res;
838 }
839 
840 static const char *cmd_next_param(const char *param, const char delimiter)
841 {
842     static const char all_delimiters[] = ",;:=";
843     char curr_delimiters[2] = {0};
844     const char *delimiters;
845 
846     if (delimiter == '?') {
847         delimiters = all_delimiters;
848     } else if (delimiter == '0') {
849         return strchr(param, '\0');
850     } else if (delimiter == '.' && *param) {
851         return param + 1;
852     } else {
853         curr_delimiters[0] = delimiter;
854         delimiters = curr_delimiters;
855     }
856 
857     param += strcspn(param, delimiters);
858     if (*param) {
859         param++;
860     }
861     return param;
862 }
863 
864 static int cmd_parse_params(const char *data, const char *schema,
865                             GArray *params)
866 {
867     const char *curr_schema, *curr_data;
868 
869     g_assert(schema);
870     g_assert(params->len == 0);
871 
872     curr_schema = schema;
873     curr_data = data;
874     while (curr_schema[0] && curr_schema[1] && *curr_data) {
875         GdbCmdVariant this_param;
876 
877         switch (curr_schema[0]) {
878         case 'l':
879             if (qemu_strtoul(curr_data, &curr_data, 16,
880                              &this_param.val_ul)) {
881                 return -EINVAL;
882             }
883             curr_data = cmd_next_param(curr_data, curr_schema[1]);
884             g_array_append_val(params, this_param);
885             break;
886         case 'L':
887             if (qemu_strtou64(curr_data, &curr_data, 16,
888                               (uint64_t *)&this_param.val_ull)) {
889                 return -EINVAL;
890             }
891             curr_data = cmd_next_param(curr_data, curr_schema[1]);
892             g_array_append_val(params, this_param);
893             break;
894         case 's':
895             this_param.data = curr_data;
896             curr_data = cmd_next_param(curr_data, curr_schema[1]);
897             g_array_append_val(params, this_param);
898             break;
899         case 'o':
900             this_param.opcode = *(uint8_t *)curr_data;
901             curr_data = cmd_next_param(curr_data, curr_schema[1]);
902             g_array_append_val(params, this_param);
903             break;
904         case 't':
905             this_param.thread_id.kind =
906                 read_thread_id(curr_data, &curr_data,
907                                &this_param.thread_id.pid,
908                                &this_param.thread_id.tid);
909             curr_data = cmd_next_param(curr_data, curr_schema[1]);
910             g_array_append_val(params, this_param);
911             break;
912         case '?':
913             curr_data = cmd_next_param(curr_data, curr_schema[1]);
914             break;
915         default:
916             return -EINVAL;
917         }
918         curr_schema += 2;
919     }
920 
921     return 0;
922 }
923 
924 static inline int startswith(const char *string, const char *pattern)
925 {
926   return !strncmp(string, pattern, strlen(pattern));
927 }
928 
929 static bool process_string_cmd(const char *data,
930                                const GdbCmdParseEntry *cmds, int num_cmds)
931 {
932     int i;
933     g_autoptr(GArray) params = g_array_new(false, true, sizeof(GdbCmdVariant));
934 
935     if (!cmds) {
936         return false;
937     }
938 
939     for (i = 0; i < num_cmds; i++) {
940         const GdbCmdParseEntry *cmd = &cmds[i];
941         void *user_ctx = NULL;
942         g_assert(cmd->handler && cmd->cmd);
943 
944         if ((cmd->cmd_startswith && !startswith(data, cmd->cmd)) ||
945             (!cmd->cmd_startswith && strcmp(cmd->cmd, data))) {
946             continue;
947         }
948 
949         if (cmd->schema) {
950             if (cmd_parse_params(&data[strlen(cmd->cmd)],
951                                  cmd->schema, params)) {
952                 return false;
953             }
954         }
955 
956         if (cmd->need_cpu_context) {
957             user_ctx = (void *)gdbserver_state.g_cpu;
958         }
959 
960         gdbserver_state.allow_stop_reply = cmd->allow_stop_reply;
961         cmd->handler(params, user_ctx);
962         return true;
963     }
964 
965     return false;
966 }
967 
968 static void run_cmd_parser(const char *data, const GdbCmdParseEntry *cmd)
969 {
970     if (!data) {
971         return;
972     }
973 
974     g_string_set_size(gdbserver_state.str_buf, 0);
975     g_byte_array_set_size(gdbserver_state.mem_buf, 0);
976 
977     /* In case there was an error during the command parsing we must
978     * send a NULL packet to indicate the command is not supported */
979     if (!process_string_cmd(data, cmd, 1)) {
980         gdb_put_packet("");
981     }
982 }
983 
984 static void handle_detach(GArray *params, void *user_ctx)
985 {
986     GDBProcess *process;
987     uint32_t pid = 1;
988 
989     if (gdbserver_state.multiprocess) {
990         if (!params->len) {
991             gdb_put_packet("E22");
992             return;
993         }
994 
995         pid = gdb_get_cmd_param(params, 0)->val_ul;
996     }
997 
998 #ifdef CONFIG_USER_ONLY
999     if (gdb_handle_detach_user(pid)) {
1000         return;
1001     }
1002 #endif
1003 
1004     process = gdb_get_process(pid);
1005     gdb_process_breakpoint_remove_all(process);
1006     process->attached = false;
1007 
1008     if (pid == gdb_get_cpu_pid(gdbserver_state.c_cpu)) {
1009         gdbserver_state.c_cpu = gdb_first_attached_cpu();
1010     }
1011 
1012     if (pid == gdb_get_cpu_pid(gdbserver_state.g_cpu)) {
1013         gdbserver_state.g_cpu = gdb_first_attached_cpu();
1014     }
1015 
1016     if (!gdbserver_state.c_cpu) {
1017         /* No more process attached */
1018         gdb_disable_syscalls();
1019         gdb_continue();
1020     }
1021     gdb_put_packet("OK");
1022 }
1023 
1024 static void handle_thread_alive(GArray *params, void *user_ctx)
1025 {
1026     CPUState *cpu;
1027 
1028     if (!params->len) {
1029         gdb_put_packet("E22");
1030         return;
1031     }
1032 
1033     if (gdb_get_cmd_param(params, 0)->thread_id.kind == GDB_READ_THREAD_ERR) {
1034         gdb_put_packet("E22");
1035         return;
1036     }
1037 
1038     cpu = gdb_get_cpu(gdb_get_cmd_param(params, 0)->thread_id.pid,
1039                       gdb_get_cmd_param(params, 0)->thread_id.tid);
1040     if (!cpu) {
1041         gdb_put_packet("E22");
1042         return;
1043     }
1044 
1045     gdb_put_packet("OK");
1046 }
1047 
1048 static void handle_continue(GArray *params, void *user_ctx)
1049 {
1050     if (params->len) {
1051         gdb_set_cpu_pc(gdb_get_cmd_param(params, 0)->val_ull);
1052     }
1053 
1054     gdbserver_state.signal = 0;
1055     gdb_continue();
1056 }
1057 
1058 static void handle_cont_with_sig(GArray *params, void *user_ctx)
1059 {
1060     unsigned long signal = 0;
1061 
1062     /*
1063      * Note: C sig;[addr] is currently unsupported and we simply
1064      *       omit the addr parameter
1065      */
1066     if (params->len) {
1067         signal = gdb_get_cmd_param(params, 0)->val_ul;
1068     }
1069 
1070     gdbserver_state.signal = gdb_signal_to_target(signal);
1071     if (gdbserver_state.signal == -1) {
1072         gdbserver_state.signal = 0;
1073     }
1074     gdb_continue();
1075 }
1076 
1077 static void handle_set_thread(GArray *params, void *user_ctx)
1078 {
1079     uint32_t pid, tid;
1080     CPUState *cpu;
1081 
1082     if (params->len != 2) {
1083         gdb_put_packet("E22");
1084         return;
1085     }
1086 
1087     if (gdb_get_cmd_param(params, 1)->thread_id.kind == GDB_READ_THREAD_ERR) {
1088         gdb_put_packet("E22");
1089         return;
1090     }
1091 
1092     if (gdb_get_cmd_param(params, 1)->thread_id.kind != GDB_ONE_THREAD) {
1093         gdb_put_packet("OK");
1094         return;
1095     }
1096 
1097     pid = gdb_get_cmd_param(params, 1)->thread_id.pid;
1098     tid = gdb_get_cmd_param(params, 1)->thread_id.tid;
1099 #ifdef CONFIG_USER_ONLY
1100     if (gdb_handle_set_thread_user(pid, tid)) {
1101         return;
1102     }
1103 #endif
1104     cpu = gdb_get_cpu(pid, tid);
1105     if (!cpu) {
1106         gdb_put_packet("E22");
1107         return;
1108     }
1109 
1110     /*
1111      * Note: This command is deprecated and modern gdb's will be using the
1112      *       vCont command instead.
1113      */
1114     switch (gdb_get_cmd_param(params, 0)->opcode) {
1115     case 'c':
1116         gdbserver_state.c_cpu = cpu;
1117         gdb_put_packet("OK");
1118         break;
1119     case 'g':
1120         gdbserver_state.g_cpu = cpu;
1121         gdb_put_packet("OK");
1122         break;
1123     default:
1124         gdb_put_packet("E22");
1125         break;
1126     }
1127 }
1128 
1129 static void handle_insert_bp(GArray *params, void *user_ctx)
1130 {
1131     int res;
1132 
1133     if (params->len != 3) {
1134         gdb_put_packet("E22");
1135         return;
1136     }
1137 
1138     res = gdb_breakpoint_insert(gdbserver_state.c_cpu,
1139                                 gdb_get_cmd_param(params, 0)->val_ul,
1140                                 gdb_get_cmd_param(params, 1)->val_ull,
1141                                 gdb_get_cmd_param(params, 2)->val_ull);
1142     if (res >= 0) {
1143         gdb_put_packet("OK");
1144         return;
1145     } else if (res == -ENOSYS) {
1146         gdb_put_packet("");
1147         return;
1148     }
1149 
1150     gdb_put_packet("E22");
1151 }
1152 
1153 static void handle_remove_bp(GArray *params, void *user_ctx)
1154 {
1155     int res;
1156 
1157     if (params->len != 3) {
1158         gdb_put_packet("E22");
1159         return;
1160     }
1161 
1162     res = gdb_breakpoint_remove(gdbserver_state.c_cpu,
1163                                 gdb_get_cmd_param(params, 0)->val_ul,
1164                                 gdb_get_cmd_param(params, 1)->val_ull,
1165                                 gdb_get_cmd_param(params, 2)->val_ull);
1166     if (res >= 0) {
1167         gdb_put_packet("OK");
1168         return;
1169     } else if (res == -ENOSYS) {
1170         gdb_put_packet("");
1171         return;
1172     }
1173 
1174     gdb_put_packet("E22");
1175 }
1176 
1177 /*
1178  * handle_set/get_reg
1179  *
1180  * Older gdb are really dumb, and don't use 'G/g' if 'P/p' is available.
1181  * This works, but can be very slow. Anything new enough to understand
1182  * XML also knows how to use this properly. However to use this we
1183  * need to define a local XML file as well as be talking to a
1184  * reasonably modern gdb. Responding with an empty packet will cause
1185  * the remote gdb to fallback to older methods.
1186  */
1187 
1188 static void handle_set_reg(GArray *params, void *user_ctx)
1189 {
1190     int reg_size;
1191 
1192     if (params->len != 2) {
1193         gdb_put_packet("E22");
1194         return;
1195     }
1196 
1197     reg_size = strlen(gdb_get_cmd_param(params, 1)->data) / 2;
1198     gdb_hextomem(gdbserver_state.mem_buf, gdb_get_cmd_param(params, 1)->data, reg_size);
1199     gdb_write_register(gdbserver_state.g_cpu, gdbserver_state.mem_buf->data,
1200                        gdb_get_cmd_param(params, 0)->val_ull);
1201     gdb_put_packet("OK");
1202 }
1203 
1204 static void handle_get_reg(GArray *params, void *user_ctx)
1205 {
1206     int reg_size;
1207 
1208     if (!params->len) {
1209         gdb_put_packet("E14");
1210         return;
1211     }
1212 
1213     reg_size = gdb_read_register(gdbserver_state.g_cpu,
1214                                  gdbserver_state.mem_buf,
1215                                  gdb_get_cmd_param(params, 0)->val_ull);
1216     if (!reg_size) {
1217         gdb_put_packet("E14");
1218         return;
1219     } else {
1220         g_byte_array_set_size(gdbserver_state.mem_buf, reg_size);
1221     }
1222 
1223     gdb_memtohex(gdbserver_state.str_buf,
1224                  gdbserver_state.mem_buf->data, reg_size);
1225     gdb_put_strbuf();
1226 }
1227 
1228 static void handle_write_mem(GArray *params, void *user_ctx)
1229 {
1230     if (params->len != 3) {
1231         gdb_put_packet("E22");
1232         return;
1233     }
1234 
1235     /* gdb_hextomem() reads 2*len bytes */
1236     if (gdb_get_cmd_param(params, 1)->val_ull >
1237         strlen(gdb_get_cmd_param(params, 2)->data) / 2) {
1238         gdb_put_packet("E22");
1239         return;
1240     }
1241 
1242     gdb_hextomem(gdbserver_state.mem_buf, gdb_get_cmd_param(params, 2)->data,
1243                  gdb_get_cmd_param(params, 1)->val_ull);
1244     if (gdb_target_memory_rw_debug(gdbserver_state.g_cpu,
1245                                    gdb_get_cmd_param(params, 0)->val_ull,
1246                                    gdbserver_state.mem_buf->data,
1247                                    gdbserver_state.mem_buf->len, true)) {
1248         gdb_put_packet("E14");
1249         return;
1250     }
1251 
1252     gdb_put_packet("OK");
1253 }
1254 
1255 static void handle_read_mem(GArray *params, void *user_ctx)
1256 {
1257     if (params->len != 2) {
1258         gdb_put_packet("E22");
1259         return;
1260     }
1261 
1262     /* gdb_memtohex() doubles the required space */
1263     if (gdb_get_cmd_param(params, 1)->val_ull > MAX_PACKET_LENGTH / 2) {
1264         gdb_put_packet("E22");
1265         return;
1266     }
1267 
1268     g_byte_array_set_size(gdbserver_state.mem_buf,
1269                           gdb_get_cmd_param(params, 1)->val_ull);
1270 
1271     if (gdb_target_memory_rw_debug(gdbserver_state.g_cpu,
1272                                    gdb_get_cmd_param(params, 0)->val_ull,
1273                                    gdbserver_state.mem_buf->data,
1274                                    gdbserver_state.mem_buf->len, false)) {
1275         gdb_put_packet("E14");
1276         return;
1277     }
1278 
1279     gdb_memtohex(gdbserver_state.str_buf, gdbserver_state.mem_buf->data,
1280              gdbserver_state.mem_buf->len);
1281     gdb_put_strbuf();
1282 }
1283 
1284 static void handle_write_all_regs(GArray *params, void *user_ctx)
1285 {
1286     int reg_id;
1287     size_t len;
1288     uint8_t *registers;
1289     int reg_size;
1290 
1291     if (!params->len) {
1292         return;
1293     }
1294 
1295     cpu_synchronize_state(gdbserver_state.g_cpu);
1296     len = strlen(gdb_get_cmd_param(params, 0)->data) / 2;
1297     gdb_hextomem(gdbserver_state.mem_buf, gdb_get_cmd_param(params, 0)->data, len);
1298     registers = gdbserver_state.mem_buf->data;
1299     for (reg_id = 0;
1300          reg_id < gdbserver_state.g_cpu->gdb_num_g_regs && len > 0;
1301          reg_id++) {
1302         reg_size = gdb_write_register(gdbserver_state.g_cpu, registers, reg_id);
1303         len -= reg_size;
1304         registers += reg_size;
1305     }
1306     gdb_put_packet("OK");
1307 }
1308 
1309 static void handle_read_all_regs(GArray *params, void *user_ctx)
1310 {
1311     int reg_id;
1312     size_t len;
1313 
1314     cpu_synchronize_state(gdbserver_state.g_cpu);
1315     g_byte_array_set_size(gdbserver_state.mem_buf, 0);
1316     len = 0;
1317     for (reg_id = 0; reg_id < gdbserver_state.g_cpu->gdb_num_g_regs; reg_id++) {
1318         len += gdb_read_register(gdbserver_state.g_cpu,
1319                                  gdbserver_state.mem_buf,
1320                                  reg_id);
1321     }
1322     g_assert(len == gdbserver_state.mem_buf->len);
1323 
1324     gdb_memtohex(gdbserver_state.str_buf, gdbserver_state.mem_buf->data, len);
1325     gdb_put_strbuf();
1326 }
1327 
1328 
1329 static void handle_step(GArray *params, void *user_ctx)
1330 {
1331     if (params->len) {
1332         gdb_set_cpu_pc(gdb_get_cmd_param(params, 0)->val_ull);
1333     }
1334 
1335     cpu_single_step(gdbserver_state.c_cpu, gdbserver_state.sstep_flags);
1336     gdb_continue();
1337 }
1338 
1339 static void handle_backward(GArray *params, void *user_ctx)
1340 {
1341     if (!gdb_can_reverse()) {
1342         gdb_put_packet("E22");
1343     }
1344     if (params->len == 1) {
1345         switch (gdb_get_cmd_param(params, 0)->opcode) {
1346         case 's':
1347             if (replay_reverse_step()) {
1348                 gdb_continue();
1349             } else {
1350                 gdb_put_packet("E14");
1351             }
1352             return;
1353         case 'c':
1354             if (replay_reverse_continue()) {
1355                 gdb_continue();
1356             } else {
1357                 gdb_put_packet("E14");
1358             }
1359             return;
1360         }
1361     }
1362 
1363     /* Default invalid command */
1364     gdb_put_packet("");
1365 }
1366 
1367 static void handle_v_cont_query(GArray *params, void *user_ctx)
1368 {
1369     gdb_put_packet("vCont;c;C;s;S");
1370 }
1371 
1372 static void handle_v_cont(GArray *params, void *user_ctx)
1373 {
1374     int res;
1375 
1376     if (!params->len) {
1377         return;
1378     }
1379 
1380     res = gdb_handle_vcont(gdb_get_cmd_param(params, 0)->data);
1381     if ((res == -EINVAL) || (res == -ERANGE)) {
1382         gdb_put_packet("E22");
1383     } else if (res) {
1384         gdb_put_packet("");
1385     }
1386 }
1387 
1388 static void handle_v_attach(GArray *params, void *user_ctx)
1389 {
1390     GDBProcess *process;
1391     CPUState *cpu;
1392 
1393     g_string_assign(gdbserver_state.str_buf, "E22");
1394     if (!params->len) {
1395         goto cleanup;
1396     }
1397 
1398     process = gdb_get_process(gdb_get_cmd_param(params, 0)->val_ul);
1399     if (!process) {
1400         goto cleanup;
1401     }
1402 
1403     cpu = gdb_get_first_cpu_in_process(process);
1404     if (!cpu) {
1405         goto cleanup;
1406     }
1407 
1408     process->attached = true;
1409     gdbserver_state.g_cpu = cpu;
1410     gdbserver_state.c_cpu = cpu;
1411 
1412     if (gdbserver_state.allow_stop_reply) {
1413         g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP);
1414         gdb_append_thread_id(cpu, gdbserver_state.str_buf);
1415         g_string_append_c(gdbserver_state.str_buf, ';');
1416         gdbserver_state.allow_stop_reply = false;
1417 cleanup:
1418         gdb_put_strbuf();
1419     }
1420 }
1421 
1422 static void handle_v_kill(GArray *params, void *user_ctx)
1423 {
1424     /* Kill the target */
1425     gdb_put_packet("OK");
1426     error_report("QEMU: Terminated via GDBstub");
1427     gdb_exit(0);
1428     gdb_qemu_exit(0);
1429 }
1430 
1431 static const GdbCmdParseEntry gdb_v_commands_table[] = {
1432     /* Order is important if has same prefix */
1433     {
1434         .handler = handle_v_cont_query,
1435         .cmd = "Cont?",
1436         .cmd_startswith = true
1437     },
1438     {
1439         .handler = handle_v_cont,
1440         .cmd = "Cont",
1441         .cmd_startswith = true,
1442         .allow_stop_reply = true,
1443         .schema = "s0"
1444     },
1445     {
1446         .handler = handle_v_attach,
1447         .cmd = "Attach;",
1448         .cmd_startswith = true,
1449         .allow_stop_reply = true,
1450         .schema = "l0"
1451     },
1452     {
1453         .handler = handle_v_kill,
1454         .cmd = "Kill;",
1455         .cmd_startswith = true
1456     },
1457 #ifdef CONFIG_USER_ONLY
1458     /*
1459      * Host I/O Packets. See [1] for details.
1460      * [1] https://sourceware.org/gdb/onlinedocs/gdb/Host-I_002fO-Packets.html
1461      */
1462     {
1463         .handler = gdb_handle_v_file_open,
1464         .cmd = "File:open:",
1465         .cmd_startswith = true,
1466         .schema = "s,L,L0"
1467     },
1468     {
1469         .handler = gdb_handle_v_file_close,
1470         .cmd = "File:close:",
1471         .cmd_startswith = true,
1472         .schema = "l0"
1473     },
1474     {
1475         .handler = gdb_handle_v_file_pread,
1476         .cmd = "File:pread:",
1477         .cmd_startswith = true,
1478         .schema = "l,L,L0"
1479     },
1480     {
1481         .handler = gdb_handle_v_file_readlink,
1482         .cmd = "File:readlink:",
1483         .cmd_startswith = true,
1484         .schema = "s0"
1485     },
1486 #endif
1487 };
1488 
1489 static void handle_v_commands(GArray *params, void *user_ctx)
1490 {
1491     if (!params->len) {
1492         return;
1493     }
1494 
1495     if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
1496                             gdb_v_commands_table,
1497                             ARRAY_SIZE(gdb_v_commands_table))) {
1498         gdb_put_packet("");
1499     }
1500 }
1501 
1502 static void handle_query_qemu_sstepbits(GArray *params, void *user_ctx)
1503 {
1504     g_string_printf(gdbserver_state.str_buf, "ENABLE=%x", SSTEP_ENABLE);
1505 
1506     if (gdbserver_state.supported_sstep_flags & SSTEP_NOIRQ) {
1507         g_string_append_printf(gdbserver_state.str_buf, ",NOIRQ=%x",
1508                                SSTEP_NOIRQ);
1509     }
1510 
1511     if (gdbserver_state.supported_sstep_flags & SSTEP_NOTIMER) {
1512         g_string_append_printf(gdbserver_state.str_buf, ",NOTIMER=%x",
1513                                SSTEP_NOTIMER);
1514     }
1515 
1516     gdb_put_strbuf();
1517 }
1518 
1519 static void handle_set_qemu_sstep(GArray *params, void *user_ctx)
1520 {
1521     int new_sstep_flags;
1522 
1523     if (!params->len) {
1524         return;
1525     }
1526 
1527     new_sstep_flags = gdb_get_cmd_param(params, 0)->val_ul;
1528 
1529     if (new_sstep_flags  & ~gdbserver_state.supported_sstep_flags) {
1530         gdb_put_packet("E22");
1531         return;
1532     }
1533 
1534     gdbserver_state.sstep_flags = new_sstep_flags;
1535     gdb_put_packet("OK");
1536 }
1537 
1538 static void handle_query_qemu_sstep(GArray *params, void *user_ctx)
1539 {
1540     g_string_printf(gdbserver_state.str_buf, "0x%x",
1541                     gdbserver_state.sstep_flags);
1542     gdb_put_strbuf();
1543 }
1544 
1545 static void handle_query_curr_tid(GArray *params, void *user_ctx)
1546 {
1547     CPUState *cpu;
1548     GDBProcess *process;
1549 
1550     /*
1551      * "Current thread" remains vague in the spec, so always return
1552      * the first thread of the current process (gdb returns the
1553      * first thread).
1554      */
1555     process = gdb_get_cpu_process(gdbserver_state.g_cpu);
1556     cpu = gdb_get_first_cpu_in_process(process);
1557     g_string_assign(gdbserver_state.str_buf, "QC");
1558     gdb_append_thread_id(cpu, gdbserver_state.str_buf);
1559     gdb_put_strbuf();
1560 }
1561 
1562 static void handle_query_threads(GArray *params, void *user_ctx)
1563 {
1564     if (!gdbserver_state.query_cpu) {
1565         gdb_put_packet("l");
1566         return;
1567     }
1568 
1569     g_string_assign(gdbserver_state.str_buf, "m");
1570     gdb_append_thread_id(gdbserver_state.query_cpu, gdbserver_state.str_buf);
1571     gdb_put_strbuf();
1572     gdbserver_state.query_cpu = gdb_next_attached_cpu(gdbserver_state.query_cpu);
1573 }
1574 
1575 static void handle_query_first_threads(GArray *params, void *user_ctx)
1576 {
1577     gdbserver_state.query_cpu = gdb_first_attached_cpu();
1578     handle_query_threads(params, user_ctx);
1579 }
1580 
1581 static void handle_query_thread_extra(GArray *params, void *user_ctx)
1582 {
1583     g_autoptr(GString) rs = g_string_new(NULL);
1584     CPUState *cpu;
1585 
1586     if (!params->len ||
1587         gdb_get_cmd_param(params, 0)->thread_id.kind == GDB_READ_THREAD_ERR) {
1588         gdb_put_packet("E22");
1589         return;
1590     }
1591 
1592     cpu = gdb_get_cpu(gdb_get_cmd_param(params, 0)->thread_id.pid,
1593                       gdb_get_cmd_param(params, 0)->thread_id.tid);
1594     if (!cpu) {
1595         return;
1596     }
1597 
1598     cpu_synchronize_state(cpu);
1599 
1600     if (gdbserver_state.multiprocess && (gdbserver_state.process_num > 1)) {
1601         /* Print the CPU model and name in multiprocess mode */
1602         ObjectClass *oc = object_get_class(OBJECT(cpu));
1603         const char *cpu_model = object_class_get_name(oc);
1604         const char *cpu_name =
1605             object_get_canonical_path_component(OBJECT(cpu));
1606         g_string_printf(rs, "%s %s [%s]", cpu_model, cpu_name,
1607                         cpu->halted ? "halted " : "running");
1608     } else {
1609         g_string_printf(rs, "CPU#%d [%s]", cpu->cpu_index,
1610                         cpu->halted ? "halted " : "running");
1611     }
1612     trace_gdbstub_op_extra_info(rs->str);
1613     gdb_memtohex(gdbserver_state.str_buf, (uint8_t *)rs->str, rs->len);
1614     gdb_put_strbuf();
1615 }
1616 
1617 
1618 static char **extra_query_flags;
1619 
1620 void gdb_extend_qsupported_features(char *qflags)
1621 {
1622     if (!extra_query_flags) {
1623         extra_query_flags = g_new0(char *, 2);
1624         extra_query_flags[0] = g_strdup(qflags);
1625     } else if (!g_strv_contains((const gchar * const *) extra_query_flags,
1626                                 qflags)) {
1627         int len = g_strv_length(extra_query_flags);
1628         extra_query_flags = g_realloc_n(extra_query_flags, len + 2,
1629                                         sizeof(char *));
1630         extra_query_flags[len] = g_strdup(qflags);
1631     }
1632 }
1633 
1634 static void handle_query_supported(GArray *params, void *user_ctx)
1635 {
1636     CPUClass *cc;
1637 
1638     g_string_printf(gdbserver_state.str_buf, "PacketSize=%x", MAX_PACKET_LENGTH);
1639     cc = CPU_GET_CLASS(first_cpu);
1640     if (cc->gdb_core_xml_file) {
1641         g_string_append(gdbserver_state.str_buf, ";qXfer:features:read+");
1642     }
1643 
1644     if (gdb_can_reverse()) {
1645         g_string_append(gdbserver_state.str_buf,
1646             ";ReverseStep+;ReverseContinue+");
1647     }
1648 
1649 #if defined(CONFIG_USER_ONLY)
1650 #if defined(CONFIG_LINUX)
1651     if (get_task_state(gdbserver_state.c_cpu)) {
1652         g_string_append(gdbserver_state.str_buf, ";qXfer:auxv:read+");
1653     }
1654     g_string_append(gdbserver_state.str_buf, ";QCatchSyscalls+");
1655 
1656     g_string_append(gdbserver_state.str_buf, ";qXfer:siginfo:read+");
1657 #endif
1658     g_string_append(gdbserver_state.str_buf, ";qXfer:exec-file:read+");
1659 #endif
1660 
1661     if (params->len) {
1662         const char *gdb_supported = gdb_get_cmd_param(params, 0)->data;
1663 
1664         if (strstr(gdb_supported, "multiprocess+")) {
1665             gdbserver_state.multiprocess = true;
1666         }
1667 #if defined(CONFIG_USER_ONLY)
1668         gdb_handle_query_supported_user(gdb_supported);
1669 #endif
1670     }
1671 
1672     g_string_append(gdbserver_state.str_buf, ";vContSupported+;multiprocess+");
1673 
1674     if (extra_query_flags) {
1675         int extras = g_strv_length(extra_query_flags);
1676         for (int i = 0; i < extras; i++) {
1677             g_string_append(gdbserver_state.str_buf, extra_query_flags[i]);
1678         }
1679     }
1680 
1681     gdb_put_strbuf();
1682 }
1683 
1684 static void handle_query_xfer_features(GArray *params, void *user_ctx)
1685 {
1686     GDBProcess *process;
1687     CPUClass *cc;
1688     unsigned long len, total_len, addr;
1689     const char *xml;
1690     const char *p;
1691 
1692     if (params->len < 3) {
1693         gdb_put_packet("E22");
1694         return;
1695     }
1696 
1697     process = gdb_get_cpu_process(gdbserver_state.g_cpu);
1698     cc = CPU_GET_CLASS(gdbserver_state.g_cpu);
1699     if (!cc->gdb_core_xml_file) {
1700         gdb_put_packet("");
1701         return;
1702     }
1703 
1704     p = gdb_get_cmd_param(params, 0)->data;
1705     xml = get_feature_xml(p, &p, process);
1706     if (!xml) {
1707         gdb_put_packet("E00");
1708         return;
1709     }
1710 
1711     addr = gdb_get_cmd_param(params, 1)->val_ul;
1712     len = gdb_get_cmd_param(params, 2)->val_ul;
1713     total_len = strlen(xml);
1714     if (addr > total_len) {
1715         gdb_put_packet("E00");
1716         return;
1717     }
1718 
1719     if (len > (MAX_PACKET_LENGTH - 5) / 2) {
1720         len = (MAX_PACKET_LENGTH - 5) / 2;
1721     }
1722 
1723     if (len < total_len - addr) {
1724         g_string_assign(gdbserver_state.str_buf, "m");
1725         gdb_memtox(gdbserver_state.str_buf, xml + addr, len);
1726     } else {
1727         g_string_assign(gdbserver_state.str_buf, "l");
1728         gdb_memtox(gdbserver_state.str_buf, xml + addr, total_len - addr);
1729     }
1730 
1731     gdb_put_packet_binary(gdbserver_state.str_buf->str,
1732                       gdbserver_state.str_buf->len, true);
1733 }
1734 
1735 static void handle_query_qemu_supported(GArray *params, void *user_ctx)
1736 {
1737     g_string_printf(gdbserver_state.str_buf, "sstepbits;sstep");
1738 #ifndef CONFIG_USER_ONLY
1739     g_string_append(gdbserver_state.str_buf, ";PhyMemMode");
1740 #endif
1741     gdb_put_strbuf();
1742 }
1743 
1744 static const GdbCmdParseEntry gdb_gen_query_set_common_table[] = {
1745     /* Order is important if has same prefix */
1746     {
1747         .handler = handle_query_qemu_sstepbits,
1748         .cmd = "qemu.sstepbits",
1749     },
1750     {
1751         .handler = handle_query_qemu_sstep,
1752         .cmd = "qemu.sstep",
1753     },
1754     {
1755         .handler = handle_set_qemu_sstep,
1756         .cmd = "qemu.sstep=",
1757         .cmd_startswith = true,
1758         .schema = "l0"
1759     },
1760 };
1761 
1762 /**
1763  * extend_table() - extend one of the command tables
1764  * @table: the command table to extend (or NULL)
1765  * @extensions: a list of GdbCmdParseEntry pointers
1766  *
1767  * The entries themselves should be pointers to static const
1768  * GdbCmdParseEntry entries. If the entry is already in the table we
1769  * skip adding it again.
1770  *
1771  * Returns (a potentially freshly allocated) GPtrArray of GdbCmdParseEntry
1772  */
1773 static GPtrArray *extend_table(GPtrArray *table, GPtrArray *extensions)
1774 {
1775     if (!table) {
1776         table = g_ptr_array_new();
1777     }
1778 
1779     for (int i = 0; i < extensions->len; i++) {
1780         gpointer entry = g_ptr_array_index(extensions, i);
1781         if (!g_ptr_array_find(table, entry, NULL)) {
1782             g_ptr_array_add(table, entry);
1783         }
1784     }
1785 
1786     return table;
1787 }
1788 
1789 /**
1790  * process_extended_table() - run through an extended command table
1791  * @table: the command table to check
1792  * @data: parameters
1793  *
1794  * returns true if the command was found and executed
1795  */
1796 static bool process_extended_table(GPtrArray *table, const char *data)
1797 {
1798     for (int i = 0; i < table->len; i++) {
1799         const GdbCmdParseEntry *entry = g_ptr_array_index(table, i);
1800         if (process_string_cmd(data, entry, 1)) {
1801             return true;
1802         }
1803     }
1804     return false;
1805 }
1806 
1807 
1808 /* Ptr to GdbCmdParseEntry */
1809 static GPtrArray *extended_query_table;
1810 
1811 void gdb_extend_query_table(GPtrArray *new_queries)
1812 {
1813     extended_query_table = extend_table(extended_query_table, new_queries);
1814 }
1815 
1816 static const GdbCmdParseEntry gdb_gen_query_table[] = {
1817     {
1818         .handler = handle_query_curr_tid,
1819         .cmd = "C",
1820     },
1821     {
1822         .handler = handle_query_threads,
1823         .cmd = "sThreadInfo",
1824     },
1825     {
1826         .handler = handle_query_first_threads,
1827         .cmd = "fThreadInfo",
1828     },
1829     {
1830         .handler = handle_query_thread_extra,
1831         .cmd = "ThreadExtraInfo,",
1832         .cmd_startswith = true,
1833         .schema = "t0"
1834     },
1835 #ifdef CONFIG_USER_ONLY
1836     {
1837         .handler = gdb_handle_query_offsets,
1838         .cmd = "Offsets",
1839     },
1840 #else
1841     {
1842         .handler = gdb_handle_query_rcmd,
1843         .cmd = "Rcmd,",
1844         .cmd_startswith = true,
1845         .schema = "s0"
1846     },
1847 #endif
1848     {
1849         .handler = handle_query_supported,
1850         .cmd = "Supported:",
1851         .cmd_startswith = true,
1852         .schema = "s0"
1853     },
1854     {
1855         .handler = handle_query_supported,
1856         .cmd = "Supported",
1857         .schema = "s0"
1858     },
1859     {
1860         .handler = handle_query_xfer_features,
1861         .cmd = "Xfer:features:read:",
1862         .cmd_startswith = true,
1863         .schema = "s:l,l0"
1864     },
1865 #if defined(CONFIG_USER_ONLY)
1866 #if defined(CONFIG_LINUX)
1867     {
1868         .handler = gdb_handle_query_xfer_auxv,
1869         .cmd = "Xfer:auxv:read::",
1870         .cmd_startswith = true,
1871         .schema = "l,l0"
1872     },
1873     {
1874         .handler = gdb_handle_query_xfer_siginfo,
1875         .cmd = "Xfer:siginfo:read::",
1876         .cmd_startswith = true,
1877         .schema = "l,l0"
1878      },
1879 #endif
1880     {
1881         .handler = gdb_handle_query_xfer_exec_file,
1882         .cmd = "Xfer:exec-file:read:",
1883         .cmd_startswith = true,
1884         .schema = "l:l,l0"
1885     },
1886 #endif
1887     {
1888         .handler = gdb_handle_query_attached,
1889         .cmd = "Attached:",
1890         .cmd_startswith = true
1891     },
1892     {
1893         .handler = gdb_handle_query_attached,
1894         .cmd = "Attached",
1895     },
1896     {
1897         .handler = handle_query_qemu_supported,
1898         .cmd = "qemu.Supported",
1899     },
1900 #ifndef CONFIG_USER_ONLY
1901     {
1902         .handler = gdb_handle_query_qemu_phy_mem_mode,
1903         .cmd = "qemu.PhyMemMode",
1904     },
1905 #endif
1906 };
1907 
1908 /* Ptr to GdbCmdParseEntry */
1909 static GPtrArray *extended_set_table;
1910 
1911 void gdb_extend_set_table(GPtrArray *new_set)
1912 {
1913     extended_set_table = extend_table(extended_set_table, new_set);
1914 }
1915 
1916 static const GdbCmdParseEntry gdb_gen_set_table[] = {
1917     /* Order is important if has same prefix */
1918     {
1919         .handler = handle_set_qemu_sstep,
1920         .cmd = "qemu.sstep:",
1921         .cmd_startswith = true,
1922         .schema = "l0"
1923     },
1924 #ifndef CONFIG_USER_ONLY
1925     {
1926         .handler = gdb_handle_set_qemu_phy_mem_mode,
1927         .cmd = "qemu.PhyMemMode:",
1928         .cmd_startswith = true,
1929         .schema = "l0"
1930     },
1931 #endif
1932 #if defined(CONFIG_USER_ONLY)
1933     {
1934         .handler = gdb_handle_set_catch_syscalls,
1935         .cmd = "CatchSyscalls:",
1936         .cmd_startswith = true,
1937         .schema = "s0",
1938     },
1939 #endif
1940 };
1941 
1942 static void handle_gen_query(GArray *params, void *user_ctx)
1943 {
1944     const char *data;
1945 
1946     if (!params->len) {
1947         return;
1948     }
1949 
1950     data = gdb_get_cmd_param(params, 0)->data;
1951 
1952     if (process_string_cmd(data,
1953                            gdb_gen_query_set_common_table,
1954                            ARRAY_SIZE(gdb_gen_query_set_common_table))) {
1955         return;
1956     }
1957 
1958     if (process_string_cmd(data,
1959                            gdb_gen_query_table,
1960                            ARRAY_SIZE(gdb_gen_query_table))) {
1961         return;
1962     }
1963 
1964     if (extended_query_table &&
1965         process_extended_table(extended_query_table, data)) {
1966         return;
1967     }
1968 
1969     /* Can't handle query, return Empty response. */
1970     gdb_put_packet("");
1971 }
1972 
1973 static void handle_gen_set(GArray *params, void *user_ctx)
1974 {
1975     const char *data;
1976 
1977     if (!params->len) {
1978         return;
1979     }
1980 
1981     data = gdb_get_cmd_param(params, 0)->data;
1982 
1983     if (process_string_cmd(data,
1984                            gdb_gen_query_set_common_table,
1985                            ARRAY_SIZE(gdb_gen_query_set_common_table))) {
1986         return;
1987     }
1988 
1989     if (process_string_cmd(data,
1990                            gdb_gen_set_table,
1991                            ARRAY_SIZE(gdb_gen_set_table))) {
1992         return;
1993     }
1994 
1995     if (extended_set_table &&
1996         process_extended_table(extended_set_table, data)) {
1997         return;
1998     }
1999 
2000     /* Can't handle set, return Empty response. */
2001     gdb_put_packet("");
2002 }
2003 
2004 static void handle_target_halt(GArray *params, void *user_ctx)
2005 {
2006     if (gdbserver_state.allow_stop_reply) {
2007         g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP);
2008         gdb_append_thread_id(gdbserver_state.c_cpu, gdbserver_state.str_buf);
2009         g_string_append_c(gdbserver_state.str_buf, ';');
2010         gdb_put_strbuf();
2011         gdbserver_state.allow_stop_reply = false;
2012     }
2013     /*
2014      * Remove all the breakpoints when this query is issued,
2015      * because gdb is doing an initial connect and the state
2016      * should be cleaned up.
2017      */
2018     gdb_breakpoint_remove_all(gdbserver_state.c_cpu);
2019 }
2020 
2021 static int gdb_handle_packet(const char *line_buf)
2022 {
2023     const GdbCmdParseEntry *cmd_parser = NULL;
2024 
2025     trace_gdbstub_io_command(line_buf);
2026 
2027     switch (line_buf[0]) {
2028     case '!':
2029         gdb_put_packet("OK");
2030         break;
2031     case '?':
2032         {
2033             static const GdbCmdParseEntry target_halted_cmd_desc = {
2034                 .handler = handle_target_halt,
2035                 .cmd = "?",
2036                 .cmd_startswith = true,
2037                 .allow_stop_reply = true,
2038             };
2039             cmd_parser = &target_halted_cmd_desc;
2040         }
2041         break;
2042     case 'c':
2043         {
2044             static const GdbCmdParseEntry continue_cmd_desc = {
2045                 .handler = handle_continue,
2046                 .cmd = "c",
2047                 .cmd_startswith = true,
2048                 .allow_stop_reply = true,
2049                 .schema = "L0"
2050             };
2051             cmd_parser = &continue_cmd_desc;
2052         }
2053         break;
2054     case 'C':
2055         {
2056             static const GdbCmdParseEntry cont_with_sig_cmd_desc = {
2057                 .handler = handle_cont_with_sig,
2058                 .cmd = "C",
2059                 .cmd_startswith = true,
2060                 .allow_stop_reply = true,
2061                 .schema = "l0"
2062             };
2063             cmd_parser = &cont_with_sig_cmd_desc;
2064         }
2065         break;
2066     case 'v':
2067         {
2068             static const GdbCmdParseEntry v_cmd_desc = {
2069                 .handler = handle_v_commands,
2070                 .cmd = "v",
2071                 .cmd_startswith = true,
2072                 .schema = "s0"
2073             };
2074             cmd_parser = &v_cmd_desc;
2075         }
2076         break;
2077     case 'k':
2078         /* Kill the target */
2079         error_report("QEMU: Terminated via GDBstub");
2080         gdb_exit(0);
2081         gdb_qemu_exit(0);
2082         break;
2083     case 'D':
2084         {
2085             static const GdbCmdParseEntry detach_cmd_desc = {
2086                 .handler = handle_detach,
2087                 .cmd = "D",
2088                 .cmd_startswith = true,
2089                 .schema = "?.l0"
2090             };
2091             cmd_parser = &detach_cmd_desc;
2092         }
2093         break;
2094     case 's':
2095         {
2096             static const GdbCmdParseEntry step_cmd_desc = {
2097                 .handler = handle_step,
2098                 .cmd = "s",
2099                 .cmd_startswith = true,
2100                 .allow_stop_reply = true,
2101                 .schema = "L0"
2102             };
2103             cmd_parser = &step_cmd_desc;
2104         }
2105         break;
2106     case 'b':
2107         {
2108             static const GdbCmdParseEntry backward_cmd_desc = {
2109                 .handler = handle_backward,
2110                 .cmd = "b",
2111                 .cmd_startswith = true,
2112                 .allow_stop_reply = true,
2113                 .schema = "o0"
2114             };
2115             cmd_parser = &backward_cmd_desc;
2116         }
2117         break;
2118     case 'F':
2119         {
2120             static const GdbCmdParseEntry file_io_cmd_desc = {
2121                 .handler = gdb_handle_file_io,
2122                 .cmd = "F",
2123                 .cmd_startswith = true,
2124                 .schema = "L,L,o0"
2125             };
2126             cmd_parser = &file_io_cmd_desc;
2127         }
2128         break;
2129     case 'g':
2130         {
2131             static const GdbCmdParseEntry read_all_regs_cmd_desc = {
2132                 .handler = handle_read_all_regs,
2133                 .cmd = "g",
2134                 .cmd_startswith = true
2135             };
2136             cmd_parser = &read_all_regs_cmd_desc;
2137         }
2138         break;
2139     case 'G':
2140         {
2141             static const GdbCmdParseEntry write_all_regs_cmd_desc = {
2142                 .handler = handle_write_all_regs,
2143                 .cmd = "G",
2144                 .cmd_startswith = true,
2145                 .schema = "s0"
2146             };
2147             cmd_parser = &write_all_regs_cmd_desc;
2148         }
2149         break;
2150     case 'm':
2151         {
2152             static const GdbCmdParseEntry read_mem_cmd_desc = {
2153                 .handler = handle_read_mem,
2154                 .cmd = "m",
2155                 .cmd_startswith = true,
2156                 .schema = "L,L0"
2157             };
2158             cmd_parser = &read_mem_cmd_desc;
2159         }
2160         break;
2161     case 'M':
2162         {
2163             static const GdbCmdParseEntry write_mem_cmd_desc = {
2164                 .handler = handle_write_mem,
2165                 .cmd = "M",
2166                 .cmd_startswith = true,
2167                 .schema = "L,L:s0"
2168             };
2169             cmd_parser = &write_mem_cmd_desc;
2170         }
2171         break;
2172     case 'p':
2173         {
2174             static const GdbCmdParseEntry get_reg_cmd_desc = {
2175                 .handler = handle_get_reg,
2176                 .cmd = "p",
2177                 .cmd_startswith = true,
2178                 .schema = "L0"
2179             };
2180             cmd_parser = &get_reg_cmd_desc;
2181         }
2182         break;
2183     case 'P':
2184         {
2185             static const GdbCmdParseEntry set_reg_cmd_desc = {
2186                 .handler = handle_set_reg,
2187                 .cmd = "P",
2188                 .cmd_startswith = true,
2189                 .schema = "L?s0"
2190             };
2191             cmd_parser = &set_reg_cmd_desc;
2192         }
2193         break;
2194     case 'Z':
2195         {
2196             static const GdbCmdParseEntry insert_bp_cmd_desc = {
2197                 .handler = handle_insert_bp,
2198                 .cmd = "Z",
2199                 .cmd_startswith = true,
2200                 .schema = "l?L?L0"
2201             };
2202             cmd_parser = &insert_bp_cmd_desc;
2203         }
2204         break;
2205     case 'z':
2206         {
2207             static const GdbCmdParseEntry remove_bp_cmd_desc = {
2208                 .handler = handle_remove_bp,
2209                 .cmd = "z",
2210                 .cmd_startswith = true,
2211                 .schema = "l?L?L0"
2212             };
2213             cmd_parser = &remove_bp_cmd_desc;
2214         }
2215         break;
2216     case 'H':
2217         {
2218             static const GdbCmdParseEntry set_thread_cmd_desc = {
2219                 .handler = handle_set_thread,
2220                 .cmd = "H",
2221                 .cmd_startswith = true,
2222                 .schema = "o.t0"
2223             };
2224             cmd_parser = &set_thread_cmd_desc;
2225         }
2226         break;
2227     case 'T':
2228         {
2229             static const GdbCmdParseEntry thread_alive_cmd_desc = {
2230                 .handler = handle_thread_alive,
2231                 .cmd = "T",
2232                 .cmd_startswith = true,
2233                 .schema = "t0"
2234             };
2235             cmd_parser = &thread_alive_cmd_desc;
2236         }
2237         break;
2238     case 'q':
2239         {
2240             static const GdbCmdParseEntry gen_query_cmd_desc = {
2241                 .handler = handle_gen_query,
2242                 .cmd = "q",
2243                 .cmd_startswith = true,
2244                 .schema = "s0"
2245             };
2246             cmd_parser = &gen_query_cmd_desc;
2247         }
2248         break;
2249     case 'Q':
2250         {
2251             static const GdbCmdParseEntry gen_set_cmd_desc = {
2252                 .handler = handle_gen_set,
2253                 .cmd = "Q",
2254                 .cmd_startswith = true,
2255                 .schema = "s0"
2256             };
2257             cmd_parser = &gen_set_cmd_desc;
2258         }
2259         break;
2260     default:
2261         /* put empty packet */
2262         gdb_put_packet("");
2263         break;
2264     }
2265 
2266     if (cmd_parser) {
2267         run_cmd_parser(line_buf, cmd_parser);
2268     }
2269 
2270     return RS_IDLE;
2271 }
2272 
2273 void gdb_set_stop_cpu(CPUState *cpu)
2274 {
2275     GDBProcess *p = gdb_get_cpu_process(cpu);
2276 
2277     if (!p->attached) {
2278         /*
2279          * Having a stop CPU corresponding to a process that is not attached
2280          * confuses GDB. So we ignore the request.
2281          */
2282         return;
2283     }
2284 
2285     gdbserver_state.c_cpu = cpu;
2286     gdbserver_state.g_cpu = cpu;
2287 }
2288 
2289 void gdb_read_byte(uint8_t ch)
2290 {
2291     uint8_t reply;
2292 
2293     gdbserver_state.allow_stop_reply = false;
2294 #ifndef CONFIG_USER_ONLY
2295     if (gdbserver_state.last_packet->len) {
2296         /* Waiting for a response to the last packet.  If we see the start
2297            of a new command then abandon the previous response.  */
2298         if (ch == '-') {
2299             trace_gdbstub_err_got_nack();
2300             gdb_put_buffer(gdbserver_state.last_packet->data,
2301                        gdbserver_state.last_packet->len);
2302         } else if (ch == '+') {
2303             trace_gdbstub_io_got_ack();
2304         } else {
2305             trace_gdbstub_io_got_unexpected(ch);
2306         }
2307 
2308         if (ch == '+' || ch == '$') {
2309             g_byte_array_set_size(gdbserver_state.last_packet, 0);
2310         }
2311         if (ch != '$')
2312             return;
2313     }
2314     if (runstate_is_running()) {
2315         /*
2316          * When the CPU is running, we cannot do anything except stop
2317          * it when receiving a char. This is expected on a Ctrl-C in the
2318          * gdb client. Because we are in all-stop mode, gdb sends a
2319          * 0x03 byte which is not a usual packet, so we handle it specially
2320          * here, but it does expect a stop reply.
2321          */
2322         if (ch != 0x03) {
2323             trace_gdbstub_err_unexpected_runpkt(ch);
2324         } else {
2325             gdbserver_state.allow_stop_reply = true;
2326         }
2327         vm_stop(RUN_STATE_PAUSED);
2328     } else
2329 #endif
2330     {
2331         switch(gdbserver_state.state) {
2332         case RS_IDLE:
2333             if (ch == '$') {
2334                 /* start of command packet */
2335                 gdbserver_state.line_buf_index = 0;
2336                 gdbserver_state.line_sum = 0;
2337                 gdbserver_state.state = RS_GETLINE;
2338             } else if (ch == '+') {
2339                 /*
2340                  * do nothing, gdb may preemptively send out ACKs on
2341                  * initial connection
2342                  */
2343             } else {
2344                 trace_gdbstub_err_garbage(ch);
2345             }
2346             break;
2347         case RS_GETLINE:
2348             if (ch == '}') {
2349                 /* start escape sequence */
2350                 gdbserver_state.state = RS_GETLINE_ESC;
2351                 gdbserver_state.line_sum += ch;
2352             } else if (ch == '*') {
2353                 /* start run length encoding sequence */
2354                 gdbserver_state.state = RS_GETLINE_RLE;
2355                 gdbserver_state.line_sum += ch;
2356             } else if (ch == '#') {
2357                 /* end of command, start of checksum*/
2358                 gdbserver_state.state = RS_CHKSUM1;
2359             } else if (gdbserver_state.line_buf_index >= sizeof(gdbserver_state.line_buf) - 1) {
2360                 trace_gdbstub_err_overrun();
2361                 gdbserver_state.state = RS_IDLE;
2362             } else {
2363                 /* unescaped command character */
2364                 gdbserver_state.line_buf[gdbserver_state.line_buf_index++] = ch;
2365                 gdbserver_state.line_sum += ch;
2366             }
2367             break;
2368         case RS_GETLINE_ESC:
2369             if (ch == '#') {
2370                 /* unexpected end of command in escape sequence */
2371                 gdbserver_state.state = RS_CHKSUM1;
2372             } else if (gdbserver_state.line_buf_index >= sizeof(gdbserver_state.line_buf) - 1) {
2373                 /* command buffer overrun */
2374                 trace_gdbstub_err_overrun();
2375                 gdbserver_state.state = RS_IDLE;
2376             } else {
2377                 /* parse escaped character and leave escape state */
2378                 gdbserver_state.line_buf[gdbserver_state.line_buf_index++] = ch ^ 0x20;
2379                 gdbserver_state.line_sum += ch;
2380                 gdbserver_state.state = RS_GETLINE;
2381             }
2382             break;
2383         case RS_GETLINE_RLE:
2384             /*
2385              * Run-length encoding is explained in "Debugging with GDB /
2386              * Appendix E GDB Remote Serial Protocol / Overview".
2387              */
2388             if (ch < ' ' || ch == '#' || ch == '$' || ch > 126) {
2389                 /* invalid RLE count encoding */
2390                 trace_gdbstub_err_invalid_repeat(ch);
2391                 gdbserver_state.state = RS_GETLINE;
2392             } else {
2393                 /* decode repeat length */
2394                 int repeat = ch - ' ' + 3;
2395                 if (gdbserver_state.line_buf_index + repeat >= sizeof(gdbserver_state.line_buf) - 1) {
2396                     /* that many repeats would overrun the command buffer */
2397                     trace_gdbstub_err_overrun();
2398                     gdbserver_state.state = RS_IDLE;
2399                 } else if (gdbserver_state.line_buf_index < 1) {
2400                     /* got a repeat but we have nothing to repeat */
2401                     trace_gdbstub_err_invalid_rle();
2402                     gdbserver_state.state = RS_GETLINE;
2403                 } else {
2404                     /* repeat the last character */
2405                     memset(gdbserver_state.line_buf + gdbserver_state.line_buf_index,
2406                            gdbserver_state.line_buf[gdbserver_state.line_buf_index - 1], repeat);
2407                     gdbserver_state.line_buf_index += repeat;
2408                     gdbserver_state.line_sum += ch;
2409                     gdbserver_state.state = RS_GETLINE;
2410                 }
2411             }
2412             break;
2413         case RS_CHKSUM1:
2414             /* get high hex digit of checksum */
2415             if (!isxdigit(ch)) {
2416                 trace_gdbstub_err_checksum_invalid(ch);
2417                 gdbserver_state.state = RS_GETLINE;
2418                 break;
2419             }
2420             gdbserver_state.line_buf[gdbserver_state.line_buf_index] = '\0';
2421             gdbserver_state.line_csum = fromhex(ch) << 4;
2422             gdbserver_state.state = RS_CHKSUM2;
2423             break;
2424         case RS_CHKSUM2:
2425             /* get low hex digit of checksum */
2426             if (!isxdigit(ch)) {
2427                 trace_gdbstub_err_checksum_invalid(ch);
2428                 gdbserver_state.state = RS_GETLINE;
2429                 break;
2430             }
2431             gdbserver_state.line_csum |= fromhex(ch);
2432 
2433             if (gdbserver_state.line_csum != (gdbserver_state.line_sum & 0xff)) {
2434                 trace_gdbstub_err_checksum_incorrect(gdbserver_state.line_sum, gdbserver_state.line_csum);
2435                 /* send NAK reply */
2436                 reply = '-';
2437                 gdb_put_buffer(&reply, 1);
2438                 gdbserver_state.state = RS_IDLE;
2439             } else {
2440                 /* send ACK reply */
2441                 reply = '+';
2442                 gdb_put_buffer(&reply, 1);
2443                 gdbserver_state.state = gdb_handle_packet(gdbserver_state.line_buf);
2444             }
2445             break;
2446         default:
2447             abort();
2448         }
2449     }
2450 }
2451 
2452 /*
2453  * Create the process that will contain all the "orphan" CPUs (that are not
2454  * part of a CPU cluster). Note that if this process contains no CPUs, it won't
2455  * be attachable and thus will be invisible to the user.
2456  */
2457 void gdb_create_default_process(GDBState *s)
2458 {
2459     GDBProcess *process;
2460     int pid;
2461 
2462 #ifdef CONFIG_USER_ONLY
2463     assert(gdbserver_state.process_num == 0);
2464     pid = getpid();
2465 #else
2466     if (gdbserver_state.process_num) {
2467         pid = s->processes[s->process_num - 1].pid;
2468     } else {
2469         pid = 0;
2470     }
2471     /* We need an available PID slot for this process */
2472     assert(pid < UINT32_MAX);
2473     pid++;
2474 #endif
2475 
2476     s->processes = g_renew(GDBProcess, s->processes, ++s->process_num);
2477     process = &s->processes[s->process_num - 1];
2478     process->pid = pid;
2479     process->attached = false;
2480     process->target_xml = NULL;
2481 }
2482 
2483