xref: /openbmc/qemu/semihosting/syscalls.c (revision a1a62ced)
1 /*
2  * Syscall implementations for semihosting.
3  *
4  * Copyright (c) 2022 Linaro
5  *
6  * SPDX-License-Identifier: GPL-2.0-or-later
7  */
8 
9 #include "qemu/osdep.h"
10 #include "cpu.h"
11 #include "gdbstub/syscalls.h"
12 #include "semihosting/guestfd.h"
13 #include "semihosting/syscalls.h"
14 #include "semihosting/console.h"
15 #ifdef CONFIG_USER_ONLY
16 #include "qemu.h"
17 #else
18 #include "semihosting/softmmu-uaccess.h"
19 #endif
20 
21 
22 /*
23  * Validate or compute the length of the string (including terminator).
24  */
25 static int validate_strlen(CPUState *cs, target_ulong str, target_ulong tlen)
26 {
27     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
28     char c;
29 
30     if (tlen == 0) {
31         ssize_t slen = target_strlen(str);
32 
33         if (slen < 0) {
34             return -EFAULT;
35         }
36         if (slen >= INT32_MAX) {
37             return -ENAMETOOLONG;
38         }
39         return slen + 1;
40     }
41     if (tlen > INT32_MAX) {
42         return -ENAMETOOLONG;
43     }
44     if (get_user_u8(c, str + tlen - 1)) {
45         return -EFAULT;
46     }
47     if (c != 0) {
48         return -EINVAL;
49     }
50     return tlen;
51 }
52 
53 static int validate_lock_user_string(char **pstr, CPUState *cs,
54                                      target_ulong tstr, target_ulong tlen)
55 {
56     int ret = validate_strlen(cs, tstr, tlen);
57     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
58     char *str = NULL;
59 
60     if (ret > 0) {
61         str = lock_user(VERIFY_READ, tstr, ret, true);
62         ret = str ? 0 : -EFAULT;
63     }
64     *pstr = str;
65     return ret;
66 }
67 
68 /*
69  * TODO: Note that gdb always stores the stat structure big-endian.
70  * So far, that's ok, as the only two targets using this are also
71  * big-endian.  Until we do something with gdb, also produce the
72  * same big-endian result from the host.
73  */
74 static int copy_stat_to_user(CPUState *cs, target_ulong addr,
75                              const struct stat *s)
76 {
77     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
78     struct gdb_stat *p;
79 
80     if (s->st_dev != (uint32_t)s->st_dev ||
81         s->st_ino != (uint32_t)s->st_ino) {
82         return -EOVERFLOW;
83     }
84 
85     p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
86     if (!p) {
87         return -EFAULT;
88     }
89 
90     p->gdb_st_dev = cpu_to_be32(s->st_dev);
91     p->gdb_st_ino = cpu_to_be32(s->st_ino);
92     p->gdb_st_mode = cpu_to_be32(s->st_mode);
93     p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
94     p->gdb_st_uid = cpu_to_be32(s->st_uid);
95     p->gdb_st_gid = cpu_to_be32(s->st_gid);
96     p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
97     p->gdb_st_size = cpu_to_be64(s->st_size);
98 #ifdef _WIN32
99     /* Windows stat is missing some fields.  */
100     p->gdb_st_blksize = 0;
101     p->gdb_st_blocks = 0;
102 #else
103     p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
104     p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
105 #endif
106     p->gdb_st_atime = cpu_to_be32(s->st_atime);
107     p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
108     p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
109 
110     unlock_user(p, addr, sizeof(struct gdb_stat));
111     return 0;
112 }
113 
114 /*
115  * GDB semihosting syscall implementations.
116  */
117 
118 static gdb_syscall_complete_cb gdb_open_complete;
119 
120 static void gdb_open_cb(CPUState *cs, uint64_t ret, int err)
121 {
122     if (!err) {
123         int guestfd = alloc_guestfd();
124         associate_guestfd(guestfd, ret);
125         ret = guestfd;
126     }
127     gdb_open_complete(cs, ret, err);
128 }
129 
130 static void gdb_open(CPUState *cs, gdb_syscall_complete_cb complete,
131                      target_ulong fname, target_ulong fname_len,
132                      int gdb_flags, int mode)
133 {
134     int len = validate_strlen(cs, fname, fname_len);
135     if (len < 0) {
136         complete(cs, -1, -len);
137         return;
138     }
139 
140     gdb_open_complete = complete;
141     gdb_do_syscall(gdb_open_cb, "open,%s,%x,%x",
142                    (uint64_t)fname, (uint32_t)len,
143                    (uint32_t)gdb_flags, (uint32_t)mode);
144 }
145 
146 static void gdb_close(CPUState *cs, gdb_syscall_complete_cb complete,
147                       GuestFD *gf)
148 {
149     gdb_do_syscall(complete, "close,%x", (uint32_t)gf->hostfd);
150 }
151 
152 static void gdb_read(CPUState *cs, gdb_syscall_complete_cb complete,
153                      GuestFD *gf, target_ulong buf, target_ulong len)
154 {
155     gdb_do_syscall(complete, "read,%x,%lx,%lx",
156                    (uint32_t)gf->hostfd, (uint64_t)buf, (uint64_t)len);
157 }
158 
159 static void gdb_write(CPUState *cs, gdb_syscall_complete_cb complete,
160                       GuestFD *gf, target_ulong buf, target_ulong len)
161 {
162     gdb_do_syscall(complete, "write,%x,%lx,%lx",
163                    (uint32_t)gf->hostfd, (uint64_t)buf, (uint64_t)len);
164 }
165 
166 static void gdb_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
167                       GuestFD *gf, int64_t off, int gdb_whence)
168 {
169     gdb_do_syscall(complete, "lseek,%x,%lx,%x",
170                    (uint32_t)gf->hostfd, off, (uint32_t)gdb_whence);
171 }
172 
173 static void gdb_isatty(CPUState *cs, gdb_syscall_complete_cb complete,
174                        GuestFD *gf)
175 {
176     gdb_do_syscall(complete, "isatty,%x", (uint32_t)gf->hostfd);
177 }
178 
179 static void gdb_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
180                       GuestFD *gf, target_ulong addr)
181 {
182     gdb_do_syscall(complete, "fstat,%x,%lx",
183                    (uint32_t)gf->hostfd, (uint64_t)addr);
184 }
185 
186 static void gdb_stat(CPUState *cs, gdb_syscall_complete_cb complete,
187                      target_ulong fname, target_ulong fname_len,
188                      target_ulong addr)
189 {
190     int len = validate_strlen(cs, fname, fname_len);
191     if (len < 0) {
192         complete(cs, -1, -len);
193         return;
194     }
195 
196     gdb_do_syscall(complete, "stat,%s,%lx",
197                    (uint64_t)fname, (uint32_t)len, (uint64_t)addr);
198 }
199 
200 static void gdb_remove(CPUState *cs, gdb_syscall_complete_cb complete,
201                        target_ulong fname, target_ulong fname_len)
202 {
203     int len = validate_strlen(cs, fname, fname_len);
204     if (len < 0) {
205         complete(cs, -1, -len);
206         return;
207     }
208 
209     gdb_do_syscall(complete, "unlink,%s", (uint64_t)fname, (uint32_t)len);
210 }
211 
212 static void gdb_rename(CPUState *cs, gdb_syscall_complete_cb complete,
213                        target_ulong oname, target_ulong oname_len,
214                        target_ulong nname, target_ulong nname_len)
215 {
216     int olen, nlen;
217 
218     olen = validate_strlen(cs, oname, oname_len);
219     if (olen < 0) {
220         complete(cs, -1, -olen);
221         return;
222     }
223     nlen = validate_strlen(cs, nname, nname_len);
224     if (nlen < 0) {
225         complete(cs, -1, -nlen);
226         return;
227     }
228 
229     gdb_do_syscall(complete, "rename,%s,%s",
230                    (uint64_t)oname, (uint32_t)olen,
231                    (uint64_t)nname, (uint32_t)nlen);
232 }
233 
234 static void gdb_system(CPUState *cs, gdb_syscall_complete_cb complete,
235                        target_ulong cmd, target_ulong cmd_len)
236 {
237     int len = validate_strlen(cs, cmd, cmd_len);
238     if (len < 0) {
239         complete(cs, -1, -len);
240         return;
241     }
242 
243     gdb_do_syscall(complete, "system,%s", (uint64_t)cmd, (uint32_t)len);
244 }
245 
246 static void gdb_gettimeofday(CPUState *cs, gdb_syscall_complete_cb complete,
247                              target_ulong tv_addr, target_ulong tz_addr)
248 {
249     gdb_do_syscall(complete, "gettimeofday,%lx,%lx",
250                    (uint64_t)tv_addr, (uint64_t)tz_addr);
251 }
252 
253 /*
254  * Host semihosting syscall implementations.
255  */
256 
257 static void host_open(CPUState *cs, gdb_syscall_complete_cb complete,
258                       target_ulong fname, target_ulong fname_len,
259                       int gdb_flags, int mode)
260 {
261     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
262     char *p;
263     int ret, host_flags = O_BINARY;
264 
265     ret = validate_lock_user_string(&p, cs, fname, fname_len);
266     if (ret < 0) {
267         complete(cs, -1, -ret);
268         return;
269     }
270 
271     if (gdb_flags & GDB_O_WRONLY) {
272         host_flags |= O_WRONLY;
273     } else if (gdb_flags & GDB_O_RDWR) {
274         host_flags |= O_RDWR;
275     } else {
276         host_flags |= O_RDONLY;
277     }
278     if (gdb_flags & GDB_O_CREAT) {
279         host_flags |= O_CREAT;
280     }
281     if (gdb_flags & GDB_O_TRUNC) {
282         host_flags |= O_TRUNC;
283     }
284     if (gdb_flags & GDB_O_EXCL) {
285         host_flags |= O_EXCL;
286     }
287 
288     ret = open(p, host_flags, mode);
289     if (ret < 0) {
290         complete(cs, -1, errno);
291     } else {
292         int guestfd = alloc_guestfd();
293         associate_guestfd(guestfd, ret);
294         complete(cs, guestfd, 0);
295     }
296     unlock_user(p, fname, 0);
297 }
298 
299 static void host_close(CPUState *cs, gdb_syscall_complete_cb complete,
300                        GuestFD *gf)
301 {
302     /*
303      * Only close the underlying host fd if it's one we opened on behalf
304      * of the guest in SYS_OPEN.
305      */
306     if (gf->hostfd != STDIN_FILENO &&
307         gf->hostfd != STDOUT_FILENO &&
308         gf->hostfd != STDERR_FILENO &&
309         close(gf->hostfd) < 0) {
310         complete(cs, -1, errno);
311     } else {
312         complete(cs, 0, 0);
313     }
314 }
315 
316 static void host_read(CPUState *cs, gdb_syscall_complete_cb complete,
317                       GuestFD *gf, target_ulong buf, target_ulong len)
318 {
319     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
320     void *ptr = lock_user(VERIFY_WRITE, buf, len, 0);
321     ssize_t ret;
322 
323     if (!ptr) {
324         complete(cs, -1, EFAULT);
325         return;
326     }
327     ret = RETRY_ON_EINTR(read(gf->hostfd, ptr, len));
328     if (ret == -1) {
329         unlock_user(ptr, buf, 0);
330         complete(cs, -1, errno);
331     } else {
332         unlock_user(ptr, buf, ret);
333         complete(cs, ret, 0);
334     }
335 }
336 
337 static void host_write(CPUState *cs, gdb_syscall_complete_cb complete,
338                        GuestFD *gf, target_ulong buf, target_ulong len)
339 {
340     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
341     void *ptr = lock_user(VERIFY_READ, buf, len, 1);
342     ssize_t ret;
343 
344     if (!ptr) {
345         complete(cs, -1, EFAULT);
346         return;
347     }
348     ret = write(gf->hostfd, ptr, len);
349     unlock_user(ptr, buf, 0);
350     complete(cs, ret, ret == -1 ? errno : 0);
351 }
352 
353 static void host_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
354                        GuestFD *gf, int64_t off, int whence)
355 {
356     /* So far, all hosts use the same values. */
357     QEMU_BUILD_BUG_ON(GDB_SEEK_SET != SEEK_SET);
358     QEMU_BUILD_BUG_ON(GDB_SEEK_CUR != SEEK_CUR);
359     QEMU_BUILD_BUG_ON(GDB_SEEK_END != SEEK_END);
360 
361     off_t ret = off;
362     int err = 0;
363 
364     if (ret == off) {
365         ret = lseek(gf->hostfd, ret, whence);
366         if (ret == -1) {
367             err = errno;
368         }
369     } else {
370         ret = -1;
371         err = EINVAL;
372     }
373     complete(cs, ret, err);
374 }
375 
376 static void host_isatty(CPUState *cs, gdb_syscall_complete_cb complete,
377                         GuestFD *gf)
378 {
379     int ret = isatty(gf->hostfd);
380     complete(cs, ret, ret ? 0 : errno);
381 }
382 
383 static void host_flen(CPUState *cs, gdb_syscall_complete_cb complete,
384                       GuestFD *gf)
385 {
386     struct stat buf;
387 
388     if (fstat(gf->hostfd, &buf) < 0) {
389         complete(cs, -1, errno);
390     } else {
391         complete(cs, buf.st_size, 0);
392     }
393 }
394 
395 static void host_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
396                        GuestFD *gf, target_ulong addr)
397 {
398     struct stat buf;
399     int ret;
400 
401     ret = fstat(gf->hostfd, &buf);
402     if (ret) {
403         complete(cs, -1, errno);
404         return;
405     }
406     ret = copy_stat_to_user(cs, addr, &buf);
407     complete(cs, ret ? -1 : 0, ret ? -ret : 0);
408 }
409 
410 static void host_stat(CPUState *cs, gdb_syscall_complete_cb complete,
411                       target_ulong fname, target_ulong fname_len,
412                       target_ulong addr)
413 {
414     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
415     struct stat buf;
416     char *name;
417     int ret, err;
418 
419     ret = validate_lock_user_string(&name, cs, fname, fname_len);
420     if (ret < 0) {
421         complete(cs, -1, -ret);
422         return;
423     }
424 
425     ret = stat(name, &buf);
426     if (ret) {
427         err = errno;
428     } else {
429         ret = copy_stat_to_user(cs, addr, &buf);
430         err = 0;
431         if (ret < 0) {
432             err = -ret;
433             ret = -1;
434         }
435     }
436     unlock_user(name, fname, 0);
437     complete(cs, ret, err);
438 }
439 
440 static void host_remove(CPUState *cs, gdb_syscall_complete_cb complete,
441                         target_ulong fname, target_ulong fname_len)
442 {
443     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
444     char *p;
445     int ret;
446 
447     ret = validate_lock_user_string(&p, cs, fname, fname_len);
448     if (ret < 0) {
449         complete(cs, -1, -ret);
450         return;
451     }
452 
453     ret = remove(p);
454     unlock_user(p, fname, 0);
455     complete(cs, ret, ret ? errno : 0);
456 }
457 
458 static void host_rename(CPUState *cs, gdb_syscall_complete_cb complete,
459                         target_ulong oname, target_ulong oname_len,
460                         target_ulong nname, target_ulong nname_len)
461 {
462     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
463     char *ostr, *nstr;
464     int ret;
465 
466     ret = validate_lock_user_string(&ostr, cs, oname, oname_len);
467     if (ret < 0) {
468         complete(cs, -1, -ret);
469         return;
470     }
471     ret = validate_lock_user_string(&nstr, cs, nname, nname_len);
472     if (ret < 0) {
473         unlock_user(ostr, oname, 0);
474         complete(cs, -1, -ret);
475         return;
476     }
477 
478     ret = rename(ostr, nstr);
479     unlock_user(ostr, oname, 0);
480     unlock_user(nstr, nname, 0);
481     complete(cs, ret, ret ? errno : 0);
482 }
483 
484 static void host_system(CPUState *cs, gdb_syscall_complete_cb complete,
485                         target_ulong cmd, target_ulong cmd_len)
486 {
487     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
488     char *p;
489     int ret;
490 
491     ret = validate_lock_user_string(&p, cs, cmd, cmd_len);
492     if (ret < 0) {
493         complete(cs, -1, -ret);
494         return;
495     }
496 
497     ret = system(p);
498     unlock_user(p, cmd, 0);
499     complete(cs, ret, ret == -1 ? errno : 0);
500 }
501 
502 static void host_gettimeofday(CPUState *cs, gdb_syscall_complete_cb complete,
503                               target_ulong tv_addr, target_ulong tz_addr)
504 {
505     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
506     struct gdb_timeval *p;
507     int64_t rt;
508 
509     /* GDB fails on non-null TZ, so be consistent. */
510     if (tz_addr != 0) {
511         complete(cs, -1, EINVAL);
512         return;
513     }
514 
515     p = lock_user(VERIFY_WRITE, tv_addr, sizeof(struct gdb_timeval), 0);
516     if (!p) {
517         complete(cs, -1, EFAULT);
518         return;
519     }
520 
521     /* TODO: Like stat, gdb always produces big-endian results; match it. */
522     rt = g_get_real_time();
523     p->tv_sec = cpu_to_be32(rt / G_USEC_PER_SEC);
524     p->tv_usec = cpu_to_be64(rt % G_USEC_PER_SEC);
525     unlock_user(p, tv_addr, sizeof(struct gdb_timeval));
526 }
527 
528 #ifndef CONFIG_USER_ONLY
529 static void host_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
530                           GuestFD *gf, GIOCondition cond, int timeout)
531 {
532     /*
533      * Since this is only used by xtensa in system mode, and stdio is
534      * handled through GuestFDConsole, and there are no semihosting
535      * system calls for sockets and the like, that means this descriptor
536      * must be a normal file.  Normal files never block and are thus
537      * always ready.
538      */
539     complete(cs, cond & (G_IO_IN | G_IO_OUT), 0);
540 }
541 #endif
542 
543 /*
544  * Static file semihosting syscall implementations.
545  */
546 
547 static void staticfile_read(CPUState *cs, gdb_syscall_complete_cb complete,
548                             GuestFD *gf, target_ulong buf, target_ulong len)
549 {
550     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
551     target_ulong rest = gf->staticfile.len - gf->staticfile.off;
552     void *ptr;
553 
554     if (len > rest) {
555         len = rest;
556     }
557     ptr = lock_user(VERIFY_WRITE, buf, len, 0);
558     if (!ptr) {
559         complete(cs, -1, EFAULT);
560         return;
561     }
562     memcpy(ptr, gf->staticfile.data + gf->staticfile.off, len);
563     gf->staticfile.off += len;
564     unlock_user(ptr, buf, len);
565     complete(cs, len, 0);
566 }
567 
568 static void staticfile_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
569                              GuestFD *gf, int64_t off, int gdb_whence)
570 {
571     int64_t ret;
572 
573     switch (gdb_whence) {
574     case GDB_SEEK_SET:
575         ret = off;
576         break;
577     case GDB_SEEK_CUR:
578         ret = gf->staticfile.off + off;
579         break;
580     case GDB_SEEK_END:
581         ret = gf->staticfile.len + off;
582         break;
583     default:
584         ret = -1;
585         break;
586     }
587     if (ret >= 0 && ret <= gf->staticfile.len) {
588         gf->staticfile.off = ret;
589         complete(cs, ret, 0);
590     } else {
591         complete(cs, -1, EINVAL);
592     }
593 }
594 
595 static void staticfile_flen(CPUState *cs, gdb_syscall_complete_cb complete,
596                             GuestFD *gf)
597 {
598     complete(cs, gf->staticfile.len, 0);
599 }
600 
601 /*
602  * Console semihosting syscall implementations.
603  */
604 
605 static void console_read(CPUState *cs, gdb_syscall_complete_cb complete,
606                          GuestFD *gf, target_ulong buf, target_ulong len)
607 {
608     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
609     char *ptr;
610     int ret;
611 
612     ptr = lock_user(VERIFY_WRITE, buf, len, 0);
613     if (!ptr) {
614         complete(cs, -1, EFAULT);
615         return;
616     }
617     ret = qemu_semihosting_console_read(cs, ptr, len);
618     unlock_user(ptr, buf, ret);
619     complete(cs, ret, 0);
620 }
621 
622 static void console_write(CPUState *cs, gdb_syscall_complete_cb complete,
623                           GuestFD *gf, target_ulong buf, target_ulong len)
624 {
625     CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
626     char *ptr = lock_user(VERIFY_READ, buf, len, 1);
627     int ret;
628 
629     if (!ptr) {
630         complete(cs, -1, EFAULT);
631         return;
632     }
633     ret = qemu_semihosting_console_write(ptr, len);
634     unlock_user(ptr, buf, 0);
635     complete(cs, ret ? ret : -1, ret ? 0 : EIO);
636 }
637 
638 static void console_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
639                           GuestFD *gf, target_ulong addr)
640 {
641     static const struct stat tty_buf = {
642         .st_mode = 020666,  /* S_IFCHR, ugo+rw */
643         .st_rdev = 5,       /* makedev(5, 0) -- linux /dev/tty */
644     };
645     int ret;
646 
647     ret = copy_stat_to_user(cs, addr, &tty_buf);
648     complete(cs, ret ? -1 : 0, ret ? -ret : 0);
649 }
650 
651 #ifndef CONFIG_USER_ONLY
652 static void console_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
653                              GuestFD *gf, GIOCondition cond, int timeout)
654 {
655     /* The semihosting console does not support urgent data or errors. */
656     cond &= G_IO_IN | G_IO_OUT;
657 
658     /*
659      * Since qemu_semihosting_console_write never blocks, we can
660      * consider output always ready -- leave G_IO_OUT alone.
661      * All that remains is to conditionally signal input ready.
662      * Since output ready causes an immediate return, only block
663      * for G_IO_IN alone.
664      *
665      * TODO: Implement proper timeout.  For now, only support
666      * indefinite wait or immediate poll.
667      */
668     if (cond == G_IO_IN && timeout < 0) {
669         qemu_semihosting_console_block_until_ready(cs);
670         /* We returned -- input must be ready. */
671     } else if ((cond & G_IO_IN) && !qemu_semihosting_console_ready()) {
672         cond &= ~G_IO_IN;
673     }
674 
675     complete(cs, cond, 0);
676 }
677 #endif
678 
679 /*
680  * Syscall entry points.
681  */
682 
683 void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
684                        target_ulong fname, target_ulong fname_len,
685                        int gdb_flags, int mode)
686 {
687     if (use_gdb_syscalls()) {
688         gdb_open(cs, complete, fname, fname_len, gdb_flags, mode);
689     } else {
690         host_open(cs, complete, fname, fname_len, gdb_flags, mode);
691     }
692 }
693 
694 void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete, int fd)
695 {
696     GuestFD *gf = get_guestfd(fd);
697 
698     if (!gf) {
699         complete(cs, -1, EBADF);
700         return;
701     }
702     switch (gf->type) {
703     case GuestFDGDB:
704         gdb_close(cs, complete, gf);
705         break;
706     case GuestFDHost:
707         host_close(cs, complete, gf);
708         break;
709     case GuestFDStatic:
710     case GuestFDConsole:
711         complete(cs, 0, 0);
712         break;
713     default:
714         g_assert_not_reached();
715     }
716     dealloc_guestfd(fd);
717 }
718 
719 void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
720                           GuestFD *gf, target_ulong buf, target_ulong len)
721 {
722     /*
723      * Bound length for 64-bit guests on 32-bit hosts, not overflowing ssize_t.
724      * Note the Linux kernel does this with MAX_RW_COUNT, so it's not a bad
725      * idea to do this unconditionally.
726      */
727     if (len > INT32_MAX) {
728         len = INT32_MAX;
729     }
730     switch (gf->type) {
731     case GuestFDGDB:
732         gdb_read(cs, complete, gf, buf, len);
733         break;
734     case GuestFDHost:
735         host_read(cs, complete, gf, buf, len);
736         break;
737     case GuestFDStatic:
738         staticfile_read(cs, complete, gf, buf, len);
739         break;
740     case GuestFDConsole:
741         console_read(cs, complete, gf, buf, len);
742         break;
743     default:
744         g_assert_not_reached();
745     }
746 }
747 
748 void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
749                        int fd, target_ulong buf, target_ulong len)
750 {
751     GuestFD *gf = get_guestfd(fd);
752 
753     if (gf) {
754         semihost_sys_read_gf(cs, complete, gf, buf, len);
755     } else {
756         complete(cs, -1, EBADF);
757     }
758 }
759 
760 void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
761                            GuestFD *gf, target_ulong buf, target_ulong len)
762 {
763     /*
764      * Bound length for 64-bit guests on 32-bit hosts, not overflowing ssize_t.
765      * Note the Linux kernel does this with MAX_RW_COUNT, so it's not a bad
766      * idea to do this unconditionally.
767      */
768     if (len > INT32_MAX) {
769         len = INT32_MAX;
770     }
771     switch (gf->type) {
772     case GuestFDGDB:
773         gdb_write(cs, complete, gf, buf, len);
774         break;
775     case GuestFDHost:
776         host_write(cs, complete, gf, buf, len);
777         break;
778     case GuestFDConsole:
779         console_write(cs, complete, gf, buf, len);
780         break;
781     case GuestFDStatic:
782         /* Static files are never open for writing: EBADF. */
783         complete(cs, -1, EBADF);
784         break;
785     default:
786         g_assert_not_reached();
787     }
788 }
789 
790 void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
791                         int fd, target_ulong buf, target_ulong len)
792 {
793     GuestFD *gf = get_guestfd(fd);
794 
795     if (gf) {
796         semihost_sys_write_gf(cs, complete, gf, buf, len);
797     } else {
798         complete(cs, -1, EBADF);
799     }
800 }
801 
802 void semihost_sys_lseek(CPUState *cs, gdb_syscall_complete_cb complete,
803                         int fd, int64_t off, int gdb_whence)
804 {
805     GuestFD *gf = get_guestfd(fd);
806 
807     if (!gf) {
808         complete(cs, -1, EBADF);
809         return;
810     }
811     switch (gf->type) {
812     case GuestFDGDB:
813         gdb_lseek(cs, complete, gf, off, gdb_whence);
814         return;
815     case GuestFDHost:
816         host_lseek(cs, complete, gf, off, gdb_whence);
817         break;
818     case GuestFDStatic:
819         staticfile_lseek(cs, complete, gf, off, gdb_whence);
820         break;
821     case GuestFDConsole:
822         complete(cs, -1, ESPIPE);
823         break;
824     default:
825         g_assert_not_reached();
826     }
827 }
828 
829 void semihost_sys_isatty(CPUState *cs, gdb_syscall_complete_cb complete, int fd)
830 {
831     GuestFD *gf = get_guestfd(fd);
832 
833     if (!gf) {
834         complete(cs, 0, EBADF);
835         return;
836     }
837     switch (gf->type) {
838     case GuestFDGDB:
839         gdb_isatty(cs, complete, gf);
840         break;
841     case GuestFDHost:
842         host_isatty(cs, complete, gf);
843         break;
844     case GuestFDStatic:
845         complete(cs, 0, ENOTTY);
846         break;
847     case GuestFDConsole:
848         complete(cs, 1, 0);
849         break;
850     default:
851         g_assert_not_reached();
852     }
853 }
854 
855 void semihost_sys_flen(CPUState *cs, gdb_syscall_complete_cb fstat_cb,
856                        gdb_syscall_complete_cb flen_cb, int fd,
857                        target_ulong fstat_addr)
858 {
859     GuestFD *gf = get_guestfd(fd);
860 
861     if (!gf) {
862         flen_cb(cs, -1, EBADF);
863         return;
864     }
865     switch (gf->type) {
866     case GuestFDGDB:
867         gdb_fstat(cs, fstat_cb, gf, fstat_addr);
868         break;
869     case GuestFDHost:
870         host_flen(cs, flen_cb, gf);
871         break;
872     case GuestFDStatic:
873         staticfile_flen(cs, flen_cb, gf);
874         break;
875     case GuestFDConsole:
876     default:
877         g_assert_not_reached();
878     }
879 }
880 
881 void semihost_sys_fstat(CPUState *cs, gdb_syscall_complete_cb complete,
882                         int fd, target_ulong addr)
883 {
884     GuestFD *gf = get_guestfd(fd);
885 
886     if (!gf) {
887         complete(cs, -1, EBADF);
888         return;
889     }
890     switch (gf->type) {
891     case GuestFDGDB:
892         gdb_fstat(cs, complete, gf, addr);
893         break;
894     case GuestFDHost:
895         host_fstat(cs, complete, gf, addr);
896         break;
897     case GuestFDConsole:
898         console_fstat(cs, complete, gf, addr);
899         break;
900     case GuestFDStatic:
901     default:
902         g_assert_not_reached();
903     }
904 }
905 
906 void semihost_sys_stat(CPUState *cs, gdb_syscall_complete_cb complete,
907                        target_ulong fname, target_ulong fname_len,
908                        target_ulong addr)
909 {
910     if (use_gdb_syscalls()) {
911         gdb_stat(cs, complete, fname, fname_len, addr);
912     } else {
913         host_stat(cs, complete, fname, fname_len, addr);
914     }
915 }
916 
917 void semihost_sys_remove(CPUState *cs, gdb_syscall_complete_cb complete,
918                          target_ulong fname, target_ulong fname_len)
919 {
920     if (use_gdb_syscalls()) {
921         gdb_remove(cs, complete, fname, fname_len);
922     } else {
923         host_remove(cs, complete, fname, fname_len);
924     }
925 }
926 
927 void semihost_sys_rename(CPUState *cs, gdb_syscall_complete_cb complete,
928                          target_ulong oname, target_ulong oname_len,
929                          target_ulong nname, target_ulong nname_len)
930 {
931     if (use_gdb_syscalls()) {
932         gdb_rename(cs, complete, oname, oname_len, nname, nname_len);
933     } else {
934         host_rename(cs, complete, oname, oname_len, nname, nname_len);
935     }
936 }
937 
938 void semihost_sys_system(CPUState *cs, gdb_syscall_complete_cb complete,
939                          target_ulong cmd, target_ulong cmd_len)
940 {
941     if (use_gdb_syscalls()) {
942         gdb_system(cs, complete, cmd, cmd_len);
943     } else {
944         host_system(cs, complete, cmd, cmd_len);
945     }
946 }
947 
948 void semihost_sys_gettimeofday(CPUState *cs, gdb_syscall_complete_cb complete,
949                                target_ulong tv_addr, target_ulong tz_addr)
950 {
951     if (use_gdb_syscalls()) {
952         gdb_gettimeofday(cs, complete, tv_addr, tz_addr);
953     } else {
954         host_gettimeofday(cs, complete, tv_addr, tz_addr);
955     }
956 }
957 
958 #ifndef CONFIG_USER_ONLY
959 void semihost_sys_poll_one(CPUState *cs, gdb_syscall_complete_cb complete,
960                            int fd, GIOCondition cond, int timeout)
961 {
962     GuestFD *gf = get_guestfd(fd);
963 
964     if (!gf) {
965         complete(cs, G_IO_NVAL, 1);
966         return;
967     }
968     switch (gf->type) {
969     case GuestFDGDB:
970         complete(cs, G_IO_NVAL, 1);
971         break;
972     case GuestFDHost:
973         host_poll_one(cs, complete, gf, cond, timeout);
974         break;
975     case GuestFDConsole:
976         console_poll_one(cs, complete, gf, cond, timeout);
977         break;
978     case GuestFDStatic:
979     default:
980         g_assert_not_reached();
981     }
982 }
983 #endif
984