xref: /openbmc/qemu/gdbstub/gdbstub.c (revision 133f202b)
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         g_assert(cmd->handler && cmd->cmd);
942 
943         if ((cmd->cmd_startswith && !startswith(data, cmd->cmd)) ||
944             (!cmd->cmd_startswith && strcmp(cmd->cmd, data))) {
945             continue;
946         }
947 
948         if (cmd->schema) {
949             if (cmd_parse_params(&data[strlen(cmd->cmd)],
950                                  cmd->schema, params)) {
951                 return false;
952             }
953         }
954 
955         gdbserver_state.allow_stop_reply = cmd->allow_stop_reply;
956         cmd->handler(params, NULL);
957         return true;
958     }
959 
960     return false;
961 }
962 
963 static void run_cmd_parser(const char *data, const GdbCmdParseEntry *cmd)
964 {
965     if (!data) {
966         return;
967     }
968 
969     g_string_set_size(gdbserver_state.str_buf, 0);
970     g_byte_array_set_size(gdbserver_state.mem_buf, 0);
971 
972     /* In case there was an error during the command parsing we must
973     * send a NULL packet to indicate the command is not supported */
974     if (!process_string_cmd(data, cmd, 1)) {
975         gdb_put_packet("");
976     }
977 }
978 
979 static void handle_detach(GArray *params, void *user_ctx)
980 {
981     GDBProcess *process;
982     uint32_t pid = 1;
983 
984     if (gdbserver_state.multiprocess) {
985         if (!params->len) {
986             gdb_put_packet("E22");
987             return;
988         }
989 
990         pid = gdb_get_cmd_param(params, 0)->val_ul;
991     }
992 
993 #ifdef CONFIG_USER_ONLY
994     if (gdb_handle_detach_user(pid)) {
995         return;
996     }
997 #endif
998 
999     process = gdb_get_process(pid);
1000     gdb_process_breakpoint_remove_all(process);
1001     process->attached = false;
1002 
1003     if (pid == gdb_get_cpu_pid(gdbserver_state.c_cpu)) {
1004         gdbserver_state.c_cpu = gdb_first_attached_cpu();
1005     }
1006 
1007     if (pid == gdb_get_cpu_pid(gdbserver_state.g_cpu)) {
1008         gdbserver_state.g_cpu = gdb_first_attached_cpu();
1009     }
1010 
1011     if (!gdbserver_state.c_cpu) {
1012         /* No more process attached */
1013         gdb_disable_syscalls();
1014         gdb_continue();
1015     }
1016     gdb_put_packet("OK");
1017 }
1018 
1019 static void handle_thread_alive(GArray *params, void *user_ctx)
1020 {
1021     CPUState *cpu;
1022 
1023     if (!params->len) {
1024         gdb_put_packet("E22");
1025         return;
1026     }
1027 
1028     if (gdb_get_cmd_param(params, 0)->thread_id.kind == GDB_READ_THREAD_ERR) {
1029         gdb_put_packet("E22");
1030         return;
1031     }
1032 
1033     cpu = gdb_get_cpu(gdb_get_cmd_param(params, 0)->thread_id.pid,
1034                       gdb_get_cmd_param(params, 0)->thread_id.tid);
1035     if (!cpu) {
1036         gdb_put_packet("E22");
1037         return;
1038     }
1039 
1040     gdb_put_packet("OK");
1041 }
1042 
1043 static void handle_continue(GArray *params, void *user_ctx)
1044 {
1045     if (params->len) {
1046         gdb_set_cpu_pc(gdb_get_cmd_param(params, 0)->val_ull);
1047     }
1048 
1049     gdbserver_state.signal = 0;
1050     gdb_continue();
1051 }
1052 
1053 static void handle_cont_with_sig(GArray *params, void *user_ctx)
1054 {
1055     unsigned long signal = 0;
1056 
1057     /*
1058      * Note: C sig;[addr] is currently unsupported and we simply
1059      *       omit the addr parameter
1060      */
1061     if (params->len) {
1062         signal = gdb_get_cmd_param(params, 0)->val_ul;
1063     }
1064 
1065     gdbserver_state.signal = gdb_signal_to_target(signal);
1066     if (gdbserver_state.signal == -1) {
1067         gdbserver_state.signal = 0;
1068     }
1069     gdb_continue();
1070 }
1071 
1072 static void handle_set_thread(GArray *params, void *user_ctx)
1073 {
1074     uint32_t pid, tid;
1075     CPUState *cpu;
1076 
1077     if (params->len != 2) {
1078         gdb_put_packet("E22");
1079         return;
1080     }
1081 
1082     if (gdb_get_cmd_param(params, 1)->thread_id.kind == GDB_READ_THREAD_ERR) {
1083         gdb_put_packet("E22");
1084         return;
1085     }
1086 
1087     if (gdb_get_cmd_param(params, 1)->thread_id.kind != GDB_ONE_THREAD) {
1088         gdb_put_packet("OK");
1089         return;
1090     }
1091 
1092     pid = gdb_get_cmd_param(params, 1)->thread_id.pid;
1093     tid = gdb_get_cmd_param(params, 1)->thread_id.tid;
1094 #ifdef CONFIG_USER_ONLY
1095     if (gdb_handle_set_thread_user(pid, tid)) {
1096         return;
1097     }
1098 #endif
1099     cpu = gdb_get_cpu(pid, tid);
1100     if (!cpu) {
1101         gdb_put_packet("E22");
1102         return;
1103     }
1104 
1105     /*
1106      * Note: This command is deprecated and modern gdb's will be using the
1107      *       vCont command instead.
1108      */
1109     switch (gdb_get_cmd_param(params, 0)->opcode) {
1110     case 'c':
1111         gdbserver_state.c_cpu = cpu;
1112         gdb_put_packet("OK");
1113         break;
1114     case 'g':
1115         gdbserver_state.g_cpu = cpu;
1116         gdb_put_packet("OK");
1117         break;
1118     default:
1119         gdb_put_packet("E22");
1120         break;
1121     }
1122 }
1123 
1124 static void handle_insert_bp(GArray *params, void *user_ctx)
1125 {
1126     int res;
1127 
1128     if (params->len != 3) {
1129         gdb_put_packet("E22");
1130         return;
1131     }
1132 
1133     res = gdb_breakpoint_insert(gdbserver_state.c_cpu,
1134                                 gdb_get_cmd_param(params, 0)->val_ul,
1135                                 gdb_get_cmd_param(params, 1)->val_ull,
1136                                 gdb_get_cmd_param(params, 2)->val_ull);
1137     if (res >= 0) {
1138         gdb_put_packet("OK");
1139         return;
1140     } else if (res == -ENOSYS) {
1141         gdb_put_packet("");
1142         return;
1143     }
1144 
1145     gdb_put_packet("E22");
1146 }
1147 
1148 static void handle_remove_bp(GArray *params, void *user_ctx)
1149 {
1150     int res;
1151 
1152     if (params->len != 3) {
1153         gdb_put_packet("E22");
1154         return;
1155     }
1156 
1157     res = gdb_breakpoint_remove(gdbserver_state.c_cpu,
1158                                 gdb_get_cmd_param(params, 0)->val_ul,
1159                                 gdb_get_cmd_param(params, 1)->val_ull,
1160                                 gdb_get_cmd_param(params, 2)->val_ull);
1161     if (res >= 0) {
1162         gdb_put_packet("OK");
1163         return;
1164     } else if (res == -ENOSYS) {
1165         gdb_put_packet("");
1166         return;
1167     }
1168 
1169     gdb_put_packet("E22");
1170 }
1171 
1172 /*
1173  * handle_set/get_reg
1174  *
1175  * Older gdb are really dumb, and don't use 'G/g' if 'P/p' is available.
1176  * This works, but can be very slow. Anything new enough to understand
1177  * XML also knows how to use this properly. However to use this we
1178  * need to define a local XML file as well as be talking to a
1179  * reasonably modern gdb. Responding with an empty packet will cause
1180  * the remote gdb to fallback to older methods.
1181  */
1182 
1183 static void handle_set_reg(GArray *params, void *user_ctx)
1184 {
1185     int reg_size;
1186 
1187     if (params->len != 2) {
1188         gdb_put_packet("E22");
1189         return;
1190     }
1191 
1192     reg_size = strlen(gdb_get_cmd_param(params, 1)->data) / 2;
1193     gdb_hextomem(gdbserver_state.mem_buf, gdb_get_cmd_param(params, 1)->data, reg_size);
1194     gdb_write_register(gdbserver_state.g_cpu, gdbserver_state.mem_buf->data,
1195                        gdb_get_cmd_param(params, 0)->val_ull);
1196     gdb_put_packet("OK");
1197 }
1198 
1199 static void handle_get_reg(GArray *params, void *user_ctx)
1200 {
1201     int reg_size;
1202 
1203     if (!params->len) {
1204         gdb_put_packet("E14");
1205         return;
1206     }
1207 
1208     reg_size = gdb_read_register(gdbserver_state.g_cpu,
1209                                  gdbserver_state.mem_buf,
1210                                  gdb_get_cmd_param(params, 0)->val_ull);
1211     if (!reg_size) {
1212         gdb_put_packet("E14");
1213         return;
1214     } else {
1215         g_byte_array_set_size(gdbserver_state.mem_buf, reg_size);
1216     }
1217 
1218     gdb_memtohex(gdbserver_state.str_buf,
1219                  gdbserver_state.mem_buf->data, reg_size);
1220     gdb_put_strbuf();
1221 }
1222 
1223 static void handle_write_mem(GArray *params, void *user_ctx)
1224 {
1225     if (params->len != 3) {
1226         gdb_put_packet("E22");
1227         return;
1228     }
1229 
1230     /* gdb_hextomem() reads 2*len bytes */
1231     if (gdb_get_cmd_param(params, 1)->val_ull >
1232         strlen(gdb_get_cmd_param(params, 2)->data) / 2) {
1233         gdb_put_packet("E22");
1234         return;
1235     }
1236 
1237     gdb_hextomem(gdbserver_state.mem_buf, gdb_get_cmd_param(params, 2)->data,
1238                  gdb_get_cmd_param(params, 1)->val_ull);
1239     if (gdb_target_memory_rw_debug(gdbserver_state.g_cpu,
1240                                    gdb_get_cmd_param(params, 0)->val_ull,
1241                                    gdbserver_state.mem_buf->data,
1242                                    gdbserver_state.mem_buf->len, true)) {
1243         gdb_put_packet("E14");
1244         return;
1245     }
1246 
1247     gdb_put_packet("OK");
1248 }
1249 
1250 static void handle_read_mem(GArray *params, void *user_ctx)
1251 {
1252     if (params->len != 2) {
1253         gdb_put_packet("E22");
1254         return;
1255     }
1256 
1257     /* gdb_memtohex() doubles the required space */
1258     if (gdb_get_cmd_param(params, 1)->val_ull > MAX_PACKET_LENGTH / 2) {
1259         gdb_put_packet("E22");
1260         return;
1261     }
1262 
1263     g_byte_array_set_size(gdbserver_state.mem_buf,
1264                           gdb_get_cmd_param(params, 1)->val_ull);
1265 
1266     if (gdb_target_memory_rw_debug(gdbserver_state.g_cpu,
1267                                    gdb_get_cmd_param(params, 0)->val_ull,
1268                                    gdbserver_state.mem_buf->data,
1269                                    gdbserver_state.mem_buf->len, false)) {
1270         gdb_put_packet("E14");
1271         return;
1272     }
1273 
1274     gdb_memtohex(gdbserver_state.str_buf, gdbserver_state.mem_buf->data,
1275              gdbserver_state.mem_buf->len);
1276     gdb_put_strbuf();
1277 }
1278 
1279 static void handle_write_all_regs(GArray *params, void *user_ctx)
1280 {
1281     int reg_id;
1282     size_t len;
1283     uint8_t *registers;
1284     int reg_size;
1285 
1286     if (!params->len) {
1287         return;
1288     }
1289 
1290     cpu_synchronize_state(gdbserver_state.g_cpu);
1291     len = strlen(gdb_get_cmd_param(params, 0)->data) / 2;
1292     gdb_hextomem(gdbserver_state.mem_buf, gdb_get_cmd_param(params, 0)->data, len);
1293     registers = gdbserver_state.mem_buf->data;
1294     for (reg_id = 0;
1295          reg_id < gdbserver_state.g_cpu->gdb_num_g_regs && len > 0;
1296          reg_id++) {
1297         reg_size = gdb_write_register(gdbserver_state.g_cpu, registers, reg_id);
1298         len -= reg_size;
1299         registers += reg_size;
1300     }
1301     gdb_put_packet("OK");
1302 }
1303 
1304 static void handle_read_all_regs(GArray *params, void *user_ctx)
1305 {
1306     int reg_id;
1307     size_t len;
1308 
1309     cpu_synchronize_state(gdbserver_state.g_cpu);
1310     g_byte_array_set_size(gdbserver_state.mem_buf, 0);
1311     len = 0;
1312     for (reg_id = 0; reg_id < gdbserver_state.g_cpu->gdb_num_g_regs; reg_id++) {
1313         len += gdb_read_register(gdbserver_state.g_cpu,
1314                                  gdbserver_state.mem_buf,
1315                                  reg_id);
1316     }
1317     g_assert(len == gdbserver_state.mem_buf->len);
1318 
1319     gdb_memtohex(gdbserver_state.str_buf, gdbserver_state.mem_buf->data, len);
1320     gdb_put_strbuf();
1321 }
1322 
1323 
1324 static void handle_step(GArray *params, void *user_ctx)
1325 {
1326     if (params->len) {
1327         gdb_set_cpu_pc(gdb_get_cmd_param(params, 0)->val_ull);
1328     }
1329 
1330     cpu_single_step(gdbserver_state.c_cpu, gdbserver_state.sstep_flags);
1331     gdb_continue();
1332 }
1333 
1334 static void handle_backward(GArray *params, void *user_ctx)
1335 {
1336     if (!gdb_can_reverse()) {
1337         gdb_put_packet("E22");
1338     }
1339     if (params->len == 1) {
1340         switch (gdb_get_cmd_param(params, 0)->opcode) {
1341         case 's':
1342             if (replay_reverse_step()) {
1343                 gdb_continue();
1344             } else {
1345                 gdb_put_packet("E14");
1346             }
1347             return;
1348         case 'c':
1349             if (replay_reverse_continue()) {
1350                 gdb_continue();
1351             } else {
1352                 gdb_put_packet("E14");
1353             }
1354             return;
1355         }
1356     }
1357 
1358     /* Default invalid command */
1359     gdb_put_packet("");
1360 }
1361 
1362 static void handle_v_cont_query(GArray *params, void *user_ctx)
1363 {
1364     gdb_put_packet("vCont;c;C;s;S");
1365 }
1366 
1367 static void handle_v_cont(GArray *params, void *user_ctx)
1368 {
1369     int res;
1370 
1371     if (!params->len) {
1372         return;
1373     }
1374 
1375     res = gdb_handle_vcont(gdb_get_cmd_param(params, 0)->data);
1376     if ((res == -EINVAL) || (res == -ERANGE)) {
1377         gdb_put_packet("E22");
1378     } else if (res) {
1379         gdb_put_packet("");
1380     }
1381 }
1382 
1383 static void handle_v_attach(GArray *params, void *user_ctx)
1384 {
1385     GDBProcess *process;
1386     CPUState *cpu;
1387 
1388     g_string_assign(gdbserver_state.str_buf, "E22");
1389     if (!params->len) {
1390         goto cleanup;
1391     }
1392 
1393     process = gdb_get_process(gdb_get_cmd_param(params, 0)->val_ul);
1394     if (!process) {
1395         goto cleanup;
1396     }
1397 
1398     cpu = gdb_get_first_cpu_in_process(process);
1399     if (!cpu) {
1400         goto cleanup;
1401     }
1402 
1403     process->attached = true;
1404     gdbserver_state.g_cpu = cpu;
1405     gdbserver_state.c_cpu = cpu;
1406 
1407     if (gdbserver_state.allow_stop_reply) {
1408         g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP);
1409         gdb_append_thread_id(cpu, gdbserver_state.str_buf);
1410         g_string_append_c(gdbserver_state.str_buf, ';');
1411         gdbserver_state.allow_stop_reply = false;
1412 cleanup:
1413         gdb_put_strbuf();
1414     }
1415 }
1416 
1417 static void handle_v_kill(GArray *params, void *user_ctx)
1418 {
1419     /* Kill the target */
1420     gdb_put_packet("OK");
1421     error_report("QEMU: Terminated via GDBstub");
1422     gdb_exit(0);
1423     gdb_qemu_exit(0);
1424 }
1425 
1426 static const GdbCmdParseEntry gdb_v_commands_table[] = {
1427     /* Order is important if has same prefix */
1428     {
1429         .handler = handle_v_cont_query,
1430         .cmd = "Cont?",
1431         .cmd_startswith = 1
1432     },
1433     {
1434         .handler = handle_v_cont,
1435         .cmd = "Cont",
1436         .cmd_startswith = 1,
1437         .allow_stop_reply = true,
1438         .schema = "s0"
1439     },
1440     {
1441         .handler = handle_v_attach,
1442         .cmd = "Attach;",
1443         .cmd_startswith = 1,
1444         .allow_stop_reply = true,
1445         .schema = "l0"
1446     },
1447     {
1448         .handler = handle_v_kill,
1449         .cmd = "Kill;",
1450         .cmd_startswith = 1
1451     },
1452 #ifdef CONFIG_USER_ONLY
1453     /*
1454      * Host I/O Packets. See [1] for details.
1455      * [1] https://sourceware.org/gdb/onlinedocs/gdb/Host-I_002fO-Packets.html
1456      */
1457     {
1458         .handler = gdb_handle_v_file_open,
1459         .cmd = "File:open:",
1460         .cmd_startswith = 1,
1461         .schema = "s,L,L0"
1462     },
1463     {
1464         .handler = gdb_handle_v_file_close,
1465         .cmd = "File:close:",
1466         .cmd_startswith = 1,
1467         .schema = "l0"
1468     },
1469     {
1470         .handler = gdb_handle_v_file_pread,
1471         .cmd = "File:pread:",
1472         .cmd_startswith = 1,
1473         .schema = "l,L,L0"
1474     },
1475     {
1476         .handler = gdb_handle_v_file_readlink,
1477         .cmd = "File:readlink:",
1478         .cmd_startswith = 1,
1479         .schema = "s0"
1480     },
1481 #endif
1482 };
1483 
1484 static void handle_v_commands(GArray *params, void *user_ctx)
1485 {
1486     if (!params->len) {
1487         return;
1488     }
1489 
1490     if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
1491                             gdb_v_commands_table,
1492                             ARRAY_SIZE(gdb_v_commands_table))) {
1493         gdb_put_packet("");
1494     }
1495 }
1496 
1497 static void handle_query_qemu_sstepbits(GArray *params, void *user_ctx)
1498 {
1499     g_string_printf(gdbserver_state.str_buf, "ENABLE=%x", SSTEP_ENABLE);
1500 
1501     if (gdbserver_state.supported_sstep_flags & SSTEP_NOIRQ) {
1502         g_string_append_printf(gdbserver_state.str_buf, ",NOIRQ=%x",
1503                                SSTEP_NOIRQ);
1504     }
1505 
1506     if (gdbserver_state.supported_sstep_flags & SSTEP_NOTIMER) {
1507         g_string_append_printf(gdbserver_state.str_buf, ",NOTIMER=%x",
1508                                SSTEP_NOTIMER);
1509     }
1510 
1511     gdb_put_strbuf();
1512 }
1513 
1514 static void handle_set_qemu_sstep(GArray *params, void *user_ctx)
1515 {
1516     int new_sstep_flags;
1517 
1518     if (!params->len) {
1519         return;
1520     }
1521 
1522     new_sstep_flags = gdb_get_cmd_param(params, 0)->val_ul;
1523 
1524     if (new_sstep_flags  & ~gdbserver_state.supported_sstep_flags) {
1525         gdb_put_packet("E22");
1526         return;
1527     }
1528 
1529     gdbserver_state.sstep_flags = new_sstep_flags;
1530     gdb_put_packet("OK");
1531 }
1532 
1533 static void handle_query_qemu_sstep(GArray *params, void *user_ctx)
1534 {
1535     g_string_printf(gdbserver_state.str_buf, "0x%x",
1536                     gdbserver_state.sstep_flags);
1537     gdb_put_strbuf();
1538 }
1539 
1540 static void handle_query_curr_tid(GArray *params, void *user_ctx)
1541 {
1542     CPUState *cpu;
1543     GDBProcess *process;
1544 
1545     /*
1546      * "Current thread" remains vague in the spec, so always return
1547      * the first thread of the current process (gdb returns the
1548      * first thread).
1549      */
1550     process = gdb_get_cpu_process(gdbserver_state.g_cpu);
1551     cpu = gdb_get_first_cpu_in_process(process);
1552     g_string_assign(gdbserver_state.str_buf, "QC");
1553     gdb_append_thread_id(cpu, gdbserver_state.str_buf);
1554     gdb_put_strbuf();
1555 }
1556 
1557 static void handle_query_threads(GArray *params, void *user_ctx)
1558 {
1559     if (!gdbserver_state.query_cpu) {
1560         gdb_put_packet("l");
1561         return;
1562     }
1563 
1564     g_string_assign(gdbserver_state.str_buf, "m");
1565     gdb_append_thread_id(gdbserver_state.query_cpu, gdbserver_state.str_buf);
1566     gdb_put_strbuf();
1567     gdbserver_state.query_cpu = gdb_next_attached_cpu(gdbserver_state.query_cpu);
1568 }
1569 
1570 static void handle_query_first_threads(GArray *params, void *user_ctx)
1571 {
1572     gdbserver_state.query_cpu = gdb_first_attached_cpu();
1573     handle_query_threads(params, user_ctx);
1574 }
1575 
1576 static void handle_query_thread_extra(GArray *params, void *user_ctx)
1577 {
1578     g_autoptr(GString) rs = g_string_new(NULL);
1579     CPUState *cpu;
1580 
1581     if (!params->len ||
1582         gdb_get_cmd_param(params, 0)->thread_id.kind == GDB_READ_THREAD_ERR) {
1583         gdb_put_packet("E22");
1584         return;
1585     }
1586 
1587     cpu = gdb_get_cpu(gdb_get_cmd_param(params, 0)->thread_id.pid,
1588                       gdb_get_cmd_param(params, 0)->thread_id.tid);
1589     if (!cpu) {
1590         return;
1591     }
1592 
1593     cpu_synchronize_state(cpu);
1594 
1595     if (gdbserver_state.multiprocess && (gdbserver_state.process_num > 1)) {
1596         /* Print the CPU model and name in multiprocess mode */
1597         ObjectClass *oc = object_get_class(OBJECT(cpu));
1598         const char *cpu_model = object_class_get_name(oc);
1599         const char *cpu_name =
1600             object_get_canonical_path_component(OBJECT(cpu));
1601         g_string_printf(rs, "%s %s [%s]", cpu_model, cpu_name,
1602                         cpu->halted ? "halted " : "running");
1603     } else {
1604         g_string_printf(rs, "CPU#%d [%s]", cpu->cpu_index,
1605                         cpu->halted ? "halted " : "running");
1606     }
1607     trace_gdbstub_op_extra_info(rs->str);
1608     gdb_memtohex(gdbserver_state.str_buf, (uint8_t *)rs->str, rs->len);
1609     gdb_put_strbuf();
1610 }
1611 
1612 static void handle_query_supported(GArray *params, void *user_ctx)
1613 {
1614     CPUClass *cc;
1615 
1616     g_string_printf(gdbserver_state.str_buf, "PacketSize=%x", MAX_PACKET_LENGTH);
1617     cc = CPU_GET_CLASS(first_cpu);
1618     if (cc->gdb_core_xml_file) {
1619         g_string_append(gdbserver_state.str_buf, ";qXfer:features:read+");
1620     }
1621 
1622     if (gdb_can_reverse()) {
1623         g_string_append(gdbserver_state.str_buf,
1624             ";ReverseStep+;ReverseContinue+");
1625     }
1626 
1627 #if defined(CONFIG_USER_ONLY)
1628 #if defined(CONFIG_LINUX)
1629     if (get_task_state(gdbserver_state.c_cpu)) {
1630         g_string_append(gdbserver_state.str_buf, ";qXfer:auxv:read+");
1631     }
1632     g_string_append(gdbserver_state.str_buf, ";QCatchSyscalls+");
1633 
1634     g_string_append(gdbserver_state.str_buf, ";qXfer:siginfo:read+");
1635 #endif
1636     g_string_append(gdbserver_state.str_buf, ";qXfer:exec-file:read+");
1637 #endif
1638 
1639     if (params->len) {
1640         const char *gdb_supported = gdb_get_cmd_param(params, 0)->data;
1641 
1642         if (strstr(gdb_supported, "multiprocess+")) {
1643             gdbserver_state.multiprocess = true;
1644         }
1645 #if defined(CONFIG_USER_ONLY)
1646         gdb_handle_query_supported_user(gdb_supported);
1647 #endif
1648     }
1649 
1650     g_string_append(gdbserver_state.str_buf, ";vContSupported+;multiprocess+");
1651     gdb_put_strbuf();
1652 }
1653 
1654 static void handle_query_xfer_features(GArray *params, void *user_ctx)
1655 {
1656     GDBProcess *process;
1657     CPUClass *cc;
1658     unsigned long len, total_len, addr;
1659     const char *xml;
1660     const char *p;
1661 
1662     if (params->len < 3) {
1663         gdb_put_packet("E22");
1664         return;
1665     }
1666 
1667     process = gdb_get_cpu_process(gdbserver_state.g_cpu);
1668     cc = CPU_GET_CLASS(gdbserver_state.g_cpu);
1669     if (!cc->gdb_core_xml_file) {
1670         gdb_put_packet("");
1671         return;
1672     }
1673 
1674     p = gdb_get_cmd_param(params, 0)->data;
1675     xml = get_feature_xml(p, &p, process);
1676     if (!xml) {
1677         gdb_put_packet("E00");
1678         return;
1679     }
1680 
1681     addr = gdb_get_cmd_param(params, 1)->val_ul;
1682     len = gdb_get_cmd_param(params, 2)->val_ul;
1683     total_len = strlen(xml);
1684     if (addr > total_len) {
1685         gdb_put_packet("E00");
1686         return;
1687     }
1688 
1689     if (len > (MAX_PACKET_LENGTH - 5) / 2) {
1690         len = (MAX_PACKET_LENGTH - 5) / 2;
1691     }
1692 
1693     if (len < total_len - addr) {
1694         g_string_assign(gdbserver_state.str_buf, "m");
1695         gdb_memtox(gdbserver_state.str_buf, xml + addr, len);
1696     } else {
1697         g_string_assign(gdbserver_state.str_buf, "l");
1698         gdb_memtox(gdbserver_state.str_buf, xml + addr, total_len - addr);
1699     }
1700 
1701     gdb_put_packet_binary(gdbserver_state.str_buf->str,
1702                       gdbserver_state.str_buf->len, true);
1703 }
1704 
1705 static void handle_query_qemu_supported(GArray *params, void *user_ctx)
1706 {
1707     g_string_printf(gdbserver_state.str_buf, "sstepbits;sstep");
1708 #ifndef CONFIG_USER_ONLY
1709     g_string_append(gdbserver_state.str_buf, ";PhyMemMode");
1710 #endif
1711     gdb_put_strbuf();
1712 }
1713 
1714 static const GdbCmdParseEntry gdb_gen_query_set_common_table[] = {
1715     /* Order is important if has same prefix */
1716     {
1717         .handler = handle_query_qemu_sstepbits,
1718         .cmd = "qemu.sstepbits",
1719     },
1720     {
1721         .handler = handle_query_qemu_sstep,
1722         .cmd = "qemu.sstep",
1723     },
1724     {
1725         .handler = handle_set_qemu_sstep,
1726         .cmd = "qemu.sstep=",
1727         .cmd_startswith = 1,
1728         .schema = "l0"
1729     },
1730 };
1731 
1732 static const GdbCmdParseEntry gdb_gen_query_table[] = {
1733     {
1734         .handler = handle_query_curr_tid,
1735         .cmd = "C",
1736     },
1737     {
1738         .handler = handle_query_threads,
1739         .cmd = "sThreadInfo",
1740     },
1741     {
1742         .handler = handle_query_first_threads,
1743         .cmd = "fThreadInfo",
1744     },
1745     {
1746         .handler = handle_query_thread_extra,
1747         .cmd = "ThreadExtraInfo,",
1748         .cmd_startswith = 1,
1749         .schema = "t0"
1750     },
1751 #ifdef CONFIG_USER_ONLY
1752     {
1753         .handler = gdb_handle_query_offsets,
1754         .cmd = "Offsets",
1755     },
1756 #else
1757     {
1758         .handler = gdb_handle_query_rcmd,
1759         .cmd = "Rcmd,",
1760         .cmd_startswith = 1,
1761         .schema = "s0"
1762     },
1763 #endif
1764     {
1765         .handler = handle_query_supported,
1766         .cmd = "Supported:",
1767         .cmd_startswith = 1,
1768         .schema = "s0"
1769     },
1770     {
1771         .handler = handle_query_supported,
1772         .cmd = "Supported",
1773         .schema = "s0"
1774     },
1775     {
1776         .handler = handle_query_xfer_features,
1777         .cmd = "Xfer:features:read:",
1778         .cmd_startswith = 1,
1779         .schema = "s:l,l0"
1780     },
1781 #if defined(CONFIG_USER_ONLY)
1782 #if defined(CONFIG_LINUX)
1783     {
1784         .handler = gdb_handle_query_xfer_auxv,
1785         .cmd = "Xfer:auxv:read::",
1786         .cmd_startswith = 1,
1787         .schema = "l,l0"
1788     },
1789     {
1790         .handler = gdb_handle_query_xfer_siginfo,
1791         .cmd = "Xfer:siginfo:read::",
1792         .cmd_startswith = 1,
1793         .schema = "l,l0"
1794      },
1795 #endif
1796     {
1797         .handler = gdb_handle_query_xfer_exec_file,
1798         .cmd = "Xfer:exec-file:read:",
1799         .cmd_startswith = 1,
1800         .schema = "l:l,l0"
1801     },
1802 #endif
1803     {
1804         .handler = gdb_handle_query_attached,
1805         .cmd = "Attached:",
1806         .cmd_startswith = 1
1807     },
1808     {
1809         .handler = gdb_handle_query_attached,
1810         .cmd = "Attached",
1811     },
1812     {
1813         .handler = handle_query_qemu_supported,
1814         .cmd = "qemu.Supported",
1815     },
1816 #ifndef CONFIG_USER_ONLY
1817     {
1818         .handler = gdb_handle_query_qemu_phy_mem_mode,
1819         .cmd = "qemu.PhyMemMode",
1820     },
1821 #endif
1822 };
1823 
1824 static const GdbCmdParseEntry gdb_gen_set_table[] = {
1825     /* Order is important if has same prefix */
1826     {
1827         .handler = handle_set_qemu_sstep,
1828         .cmd = "qemu.sstep:",
1829         .cmd_startswith = 1,
1830         .schema = "l0"
1831     },
1832 #ifndef CONFIG_USER_ONLY
1833     {
1834         .handler = gdb_handle_set_qemu_phy_mem_mode,
1835         .cmd = "qemu.PhyMemMode:",
1836         .cmd_startswith = 1,
1837         .schema = "l0"
1838     },
1839 #endif
1840 #if defined(CONFIG_USER_ONLY)
1841     {
1842         .handler = gdb_handle_set_catch_syscalls,
1843         .cmd = "CatchSyscalls:",
1844         .cmd_startswith = 1,
1845         .schema = "s0",
1846     },
1847 #endif
1848 };
1849 
1850 static void handle_gen_query(GArray *params, void *user_ctx)
1851 {
1852     if (!params->len) {
1853         return;
1854     }
1855 
1856     if (process_string_cmd(gdb_get_cmd_param(params, 0)->data,
1857                            gdb_gen_query_set_common_table,
1858                            ARRAY_SIZE(gdb_gen_query_set_common_table))) {
1859         return;
1860     }
1861 
1862     if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
1863                             gdb_gen_query_table,
1864                             ARRAY_SIZE(gdb_gen_query_table))) {
1865         gdb_put_packet("");
1866     }
1867 }
1868 
1869 static void handle_gen_set(GArray *params, void *user_ctx)
1870 {
1871     if (!params->len) {
1872         return;
1873     }
1874 
1875     if (process_string_cmd(gdb_get_cmd_param(params, 0)->data,
1876                            gdb_gen_query_set_common_table,
1877                            ARRAY_SIZE(gdb_gen_query_set_common_table))) {
1878         return;
1879     }
1880 
1881     if (!process_string_cmd(gdb_get_cmd_param(params, 0)->data,
1882                            gdb_gen_set_table,
1883                            ARRAY_SIZE(gdb_gen_set_table))) {
1884         gdb_put_packet("");
1885     }
1886 }
1887 
1888 static void handle_target_halt(GArray *params, void *user_ctx)
1889 {
1890     if (gdbserver_state.allow_stop_reply) {
1891         g_string_printf(gdbserver_state.str_buf, "T%02xthread:", GDB_SIGNAL_TRAP);
1892         gdb_append_thread_id(gdbserver_state.c_cpu, gdbserver_state.str_buf);
1893         g_string_append_c(gdbserver_state.str_buf, ';');
1894         gdb_put_strbuf();
1895         gdbserver_state.allow_stop_reply = false;
1896     }
1897     /*
1898      * Remove all the breakpoints when this query is issued,
1899      * because gdb is doing an initial connect and the state
1900      * should be cleaned up.
1901      */
1902     gdb_breakpoint_remove_all(gdbserver_state.c_cpu);
1903 }
1904 
1905 static int gdb_handle_packet(const char *line_buf)
1906 {
1907     const GdbCmdParseEntry *cmd_parser = NULL;
1908 
1909     trace_gdbstub_io_command(line_buf);
1910 
1911     switch (line_buf[0]) {
1912     case '!':
1913         gdb_put_packet("OK");
1914         break;
1915     case '?':
1916         {
1917             static const GdbCmdParseEntry target_halted_cmd_desc = {
1918                 .handler = handle_target_halt,
1919                 .cmd = "?",
1920                 .cmd_startswith = 1,
1921                 .allow_stop_reply = true,
1922             };
1923             cmd_parser = &target_halted_cmd_desc;
1924         }
1925         break;
1926     case 'c':
1927         {
1928             static const GdbCmdParseEntry continue_cmd_desc = {
1929                 .handler = handle_continue,
1930                 .cmd = "c",
1931                 .cmd_startswith = 1,
1932                 .allow_stop_reply = true,
1933                 .schema = "L0"
1934             };
1935             cmd_parser = &continue_cmd_desc;
1936         }
1937         break;
1938     case 'C':
1939         {
1940             static const GdbCmdParseEntry cont_with_sig_cmd_desc = {
1941                 .handler = handle_cont_with_sig,
1942                 .cmd = "C",
1943                 .cmd_startswith = 1,
1944                 .allow_stop_reply = true,
1945                 .schema = "l0"
1946             };
1947             cmd_parser = &cont_with_sig_cmd_desc;
1948         }
1949         break;
1950     case 'v':
1951         {
1952             static const GdbCmdParseEntry v_cmd_desc = {
1953                 .handler = handle_v_commands,
1954                 .cmd = "v",
1955                 .cmd_startswith = 1,
1956                 .schema = "s0"
1957             };
1958             cmd_parser = &v_cmd_desc;
1959         }
1960         break;
1961     case 'k':
1962         /* Kill the target */
1963         error_report("QEMU: Terminated via GDBstub");
1964         gdb_exit(0);
1965         gdb_qemu_exit(0);
1966         break;
1967     case 'D':
1968         {
1969             static const GdbCmdParseEntry detach_cmd_desc = {
1970                 .handler = handle_detach,
1971                 .cmd = "D",
1972                 .cmd_startswith = 1,
1973                 .schema = "?.l0"
1974             };
1975             cmd_parser = &detach_cmd_desc;
1976         }
1977         break;
1978     case 's':
1979         {
1980             static const GdbCmdParseEntry step_cmd_desc = {
1981                 .handler = handle_step,
1982                 .cmd = "s",
1983                 .cmd_startswith = 1,
1984                 .allow_stop_reply = true,
1985                 .schema = "L0"
1986             };
1987             cmd_parser = &step_cmd_desc;
1988         }
1989         break;
1990     case 'b':
1991         {
1992             static const GdbCmdParseEntry backward_cmd_desc = {
1993                 .handler = handle_backward,
1994                 .cmd = "b",
1995                 .cmd_startswith = 1,
1996                 .allow_stop_reply = true,
1997                 .schema = "o0"
1998             };
1999             cmd_parser = &backward_cmd_desc;
2000         }
2001         break;
2002     case 'F':
2003         {
2004             static const GdbCmdParseEntry file_io_cmd_desc = {
2005                 .handler = gdb_handle_file_io,
2006                 .cmd = "F",
2007                 .cmd_startswith = 1,
2008                 .schema = "L,L,o0"
2009             };
2010             cmd_parser = &file_io_cmd_desc;
2011         }
2012         break;
2013     case 'g':
2014         {
2015             static const GdbCmdParseEntry read_all_regs_cmd_desc = {
2016                 .handler = handle_read_all_regs,
2017                 .cmd = "g",
2018                 .cmd_startswith = 1
2019             };
2020             cmd_parser = &read_all_regs_cmd_desc;
2021         }
2022         break;
2023     case 'G':
2024         {
2025             static const GdbCmdParseEntry write_all_regs_cmd_desc = {
2026                 .handler = handle_write_all_regs,
2027                 .cmd = "G",
2028                 .cmd_startswith = 1,
2029                 .schema = "s0"
2030             };
2031             cmd_parser = &write_all_regs_cmd_desc;
2032         }
2033         break;
2034     case 'm':
2035         {
2036             static const GdbCmdParseEntry read_mem_cmd_desc = {
2037                 .handler = handle_read_mem,
2038                 .cmd = "m",
2039                 .cmd_startswith = 1,
2040                 .schema = "L,L0"
2041             };
2042             cmd_parser = &read_mem_cmd_desc;
2043         }
2044         break;
2045     case 'M':
2046         {
2047             static const GdbCmdParseEntry write_mem_cmd_desc = {
2048                 .handler = handle_write_mem,
2049                 .cmd = "M",
2050                 .cmd_startswith = 1,
2051                 .schema = "L,L:s0"
2052             };
2053             cmd_parser = &write_mem_cmd_desc;
2054         }
2055         break;
2056     case 'p':
2057         {
2058             static const GdbCmdParseEntry get_reg_cmd_desc = {
2059                 .handler = handle_get_reg,
2060                 .cmd = "p",
2061                 .cmd_startswith = 1,
2062                 .schema = "L0"
2063             };
2064             cmd_parser = &get_reg_cmd_desc;
2065         }
2066         break;
2067     case 'P':
2068         {
2069             static const GdbCmdParseEntry set_reg_cmd_desc = {
2070                 .handler = handle_set_reg,
2071                 .cmd = "P",
2072                 .cmd_startswith = 1,
2073                 .schema = "L?s0"
2074             };
2075             cmd_parser = &set_reg_cmd_desc;
2076         }
2077         break;
2078     case 'Z':
2079         {
2080             static const GdbCmdParseEntry insert_bp_cmd_desc = {
2081                 .handler = handle_insert_bp,
2082                 .cmd = "Z",
2083                 .cmd_startswith = 1,
2084                 .schema = "l?L?L0"
2085             };
2086             cmd_parser = &insert_bp_cmd_desc;
2087         }
2088         break;
2089     case 'z':
2090         {
2091             static const GdbCmdParseEntry remove_bp_cmd_desc = {
2092                 .handler = handle_remove_bp,
2093                 .cmd = "z",
2094                 .cmd_startswith = 1,
2095                 .schema = "l?L?L0"
2096             };
2097             cmd_parser = &remove_bp_cmd_desc;
2098         }
2099         break;
2100     case 'H':
2101         {
2102             static const GdbCmdParseEntry set_thread_cmd_desc = {
2103                 .handler = handle_set_thread,
2104                 .cmd = "H",
2105                 .cmd_startswith = 1,
2106                 .schema = "o.t0"
2107             };
2108             cmd_parser = &set_thread_cmd_desc;
2109         }
2110         break;
2111     case 'T':
2112         {
2113             static const GdbCmdParseEntry thread_alive_cmd_desc = {
2114                 .handler = handle_thread_alive,
2115                 .cmd = "T",
2116                 .cmd_startswith = 1,
2117                 .schema = "t0"
2118             };
2119             cmd_parser = &thread_alive_cmd_desc;
2120         }
2121         break;
2122     case 'q':
2123         {
2124             static const GdbCmdParseEntry gen_query_cmd_desc = {
2125                 .handler = handle_gen_query,
2126                 .cmd = "q",
2127                 .cmd_startswith = 1,
2128                 .schema = "s0"
2129             };
2130             cmd_parser = &gen_query_cmd_desc;
2131         }
2132         break;
2133     case 'Q':
2134         {
2135             static const GdbCmdParseEntry gen_set_cmd_desc = {
2136                 .handler = handle_gen_set,
2137                 .cmd = "Q",
2138                 .cmd_startswith = 1,
2139                 .schema = "s0"
2140             };
2141             cmd_parser = &gen_set_cmd_desc;
2142         }
2143         break;
2144     default:
2145         /* put empty packet */
2146         gdb_put_packet("");
2147         break;
2148     }
2149 
2150     if (cmd_parser) {
2151         run_cmd_parser(line_buf, cmd_parser);
2152     }
2153 
2154     return RS_IDLE;
2155 }
2156 
2157 void gdb_set_stop_cpu(CPUState *cpu)
2158 {
2159     GDBProcess *p = gdb_get_cpu_process(cpu);
2160 
2161     if (!p->attached) {
2162         /*
2163          * Having a stop CPU corresponding to a process that is not attached
2164          * confuses GDB. So we ignore the request.
2165          */
2166         return;
2167     }
2168 
2169     gdbserver_state.c_cpu = cpu;
2170     gdbserver_state.g_cpu = cpu;
2171 }
2172 
2173 void gdb_read_byte(uint8_t ch)
2174 {
2175     uint8_t reply;
2176 
2177     gdbserver_state.allow_stop_reply = false;
2178 #ifndef CONFIG_USER_ONLY
2179     if (gdbserver_state.last_packet->len) {
2180         /* Waiting for a response to the last packet.  If we see the start
2181            of a new command then abandon the previous response.  */
2182         if (ch == '-') {
2183             trace_gdbstub_err_got_nack();
2184             gdb_put_buffer(gdbserver_state.last_packet->data,
2185                        gdbserver_state.last_packet->len);
2186         } else if (ch == '+') {
2187             trace_gdbstub_io_got_ack();
2188         } else {
2189             trace_gdbstub_io_got_unexpected(ch);
2190         }
2191 
2192         if (ch == '+' || ch == '$') {
2193             g_byte_array_set_size(gdbserver_state.last_packet, 0);
2194         }
2195         if (ch != '$')
2196             return;
2197     }
2198     if (runstate_is_running()) {
2199         /*
2200          * When the CPU is running, we cannot do anything except stop
2201          * it when receiving a char. This is expected on a Ctrl-C in the
2202          * gdb client. Because we are in all-stop mode, gdb sends a
2203          * 0x03 byte which is not a usual packet, so we handle it specially
2204          * here, but it does expect a stop reply.
2205          */
2206         if (ch != 0x03) {
2207             trace_gdbstub_err_unexpected_runpkt(ch);
2208         } else {
2209             gdbserver_state.allow_stop_reply = true;
2210         }
2211         vm_stop(RUN_STATE_PAUSED);
2212     } else
2213 #endif
2214     {
2215         switch(gdbserver_state.state) {
2216         case RS_IDLE:
2217             if (ch == '$') {
2218                 /* start of command packet */
2219                 gdbserver_state.line_buf_index = 0;
2220                 gdbserver_state.line_sum = 0;
2221                 gdbserver_state.state = RS_GETLINE;
2222             } else if (ch == '+') {
2223                 /*
2224                  * do nothing, gdb may preemptively send out ACKs on
2225                  * initial connection
2226                  */
2227             } else {
2228                 trace_gdbstub_err_garbage(ch);
2229             }
2230             break;
2231         case RS_GETLINE:
2232             if (ch == '}') {
2233                 /* start escape sequence */
2234                 gdbserver_state.state = RS_GETLINE_ESC;
2235                 gdbserver_state.line_sum += ch;
2236             } else if (ch == '*') {
2237                 /* start run length encoding sequence */
2238                 gdbserver_state.state = RS_GETLINE_RLE;
2239                 gdbserver_state.line_sum += ch;
2240             } else if (ch == '#') {
2241                 /* end of command, start of checksum*/
2242                 gdbserver_state.state = RS_CHKSUM1;
2243             } else if (gdbserver_state.line_buf_index >= sizeof(gdbserver_state.line_buf) - 1) {
2244                 trace_gdbstub_err_overrun();
2245                 gdbserver_state.state = RS_IDLE;
2246             } else {
2247                 /* unescaped command character */
2248                 gdbserver_state.line_buf[gdbserver_state.line_buf_index++] = ch;
2249                 gdbserver_state.line_sum += ch;
2250             }
2251             break;
2252         case RS_GETLINE_ESC:
2253             if (ch == '#') {
2254                 /* unexpected end of command in escape sequence */
2255                 gdbserver_state.state = RS_CHKSUM1;
2256             } else if (gdbserver_state.line_buf_index >= sizeof(gdbserver_state.line_buf) - 1) {
2257                 /* command buffer overrun */
2258                 trace_gdbstub_err_overrun();
2259                 gdbserver_state.state = RS_IDLE;
2260             } else {
2261                 /* parse escaped character and leave escape state */
2262                 gdbserver_state.line_buf[gdbserver_state.line_buf_index++] = ch ^ 0x20;
2263                 gdbserver_state.line_sum += ch;
2264                 gdbserver_state.state = RS_GETLINE;
2265             }
2266             break;
2267         case RS_GETLINE_RLE:
2268             /*
2269              * Run-length encoding is explained in "Debugging with GDB /
2270              * Appendix E GDB Remote Serial Protocol / Overview".
2271              */
2272             if (ch < ' ' || ch == '#' || ch == '$' || ch > 126) {
2273                 /* invalid RLE count encoding */
2274                 trace_gdbstub_err_invalid_repeat(ch);
2275                 gdbserver_state.state = RS_GETLINE;
2276             } else {
2277                 /* decode repeat length */
2278                 int repeat = ch - ' ' + 3;
2279                 if (gdbserver_state.line_buf_index + repeat >= sizeof(gdbserver_state.line_buf) - 1) {
2280                     /* that many repeats would overrun the command buffer */
2281                     trace_gdbstub_err_overrun();
2282                     gdbserver_state.state = RS_IDLE;
2283                 } else if (gdbserver_state.line_buf_index < 1) {
2284                     /* got a repeat but we have nothing to repeat */
2285                     trace_gdbstub_err_invalid_rle();
2286                     gdbserver_state.state = RS_GETLINE;
2287                 } else {
2288                     /* repeat the last character */
2289                     memset(gdbserver_state.line_buf + gdbserver_state.line_buf_index,
2290                            gdbserver_state.line_buf[gdbserver_state.line_buf_index - 1], repeat);
2291                     gdbserver_state.line_buf_index += repeat;
2292                     gdbserver_state.line_sum += ch;
2293                     gdbserver_state.state = RS_GETLINE;
2294                 }
2295             }
2296             break;
2297         case RS_CHKSUM1:
2298             /* get high hex digit of checksum */
2299             if (!isxdigit(ch)) {
2300                 trace_gdbstub_err_checksum_invalid(ch);
2301                 gdbserver_state.state = RS_GETLINE;
2302                 break;
2303             }
2304             gdbserver_state.line_buf[gdbserver_state.line_buf_index] = '\0';
2305             gdbserver_state.line_csum = fromhex(ch) << 4;
2306             gdbserver_state.state = RS_CHKSUM2;
2307             break;
2308         case RS_CHKSUM2:
2309             /* get low hex digit of checksum */
2310             if (!isxdigit(ch)) {
2311                 trace_gdbstub_err_checksum_invalid(ch);
2312                 gdbserver_state.state = RS_GETLINE;
2313                 break;
2314             }
2315             gdbserver_state.line_csum |= fromhex(ch);
2316 
2317             if (gdbserver_state.line_csum != (gdbserver_state.line_sum & 0xff)) {
2318                 trace_gdbstub_err_checksum_incorrect(gdbserver_state.line_sum, gdbserver_state.line_csum);
2319                 /* send NAK reply */
2320                 reply = '-';
2321                 gdb_put_buffer(&reply, 1);
2322                 gdbserver_state.state = RS_IDLE;
2323             } else {
2324                 /* send ACK reply */
2325                 reply = '+';
2326                 gdb_put_buffer(&reply, 1);
2327                 gdbserver_state.state = gdb_handle_packet(gdbserver_state.line_buf);
2328             }
2329             break;
2330         default:
2331             abort();
2332         }
2333     }
2334 }
2335 
2336 /*
2337  * Create the process that will contain all the "orphan" CPUs (that are not
2338  * part of a CPU cluster). Note that if this process contains no CPUs, it won't
2339  * be attachable and thus will be invisible to the user.
2340  */
2341 void gdb_create_default_process(GDBState *s)
2342 {
2343     GDBProcess *process;
2344     int pid;
2345 
2346 #ifdef CONFIG_USER_ONLY
2347     assert(gdbserver_state.process_num == 0);
2348     pid = getpid();
2349 #else
2350     if (gdbserver_state.process_num) {
2351         pid = s->processes[s->process_num - 1].pid;
2352     } else {
2353         pid = 0;
2354     }
2355     /* We need an available PID slot for this process */
2356     assert(pid < UINT32_MAX);
2357     pid++;
2358 #endif
2359 
2360     s->processes = g_renew(GDBProcess, s->processes, ++s->process_num);
2361     process = &s->processes[s->process_num - 1];
2362     process->pid = pid;
2363     process->attached = false;
2364     process->target_xml = NULL;
2365 }
2366 
2367