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Commit | Line | Data |
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ae7467b1 AB |
1 | /* |
2 | * gdbstub user-mode helper routines. | |
3 | * | |
4 | * We know for user-mode we are using TCG so we can call stuff directly. | |
5 | * | |
9455762f | 6 | * Copyright (c) 2003-2005 Fabrice Bellard |
ae7467b1 AB |
7 | * Copyright (c) 2022 Linaro Ltd |
8 | * | |
9455762f | 9 | * SPDX-License-Identifier: LGPL-2.0+ |
ae7467b1 AB |
10 | */ |
11 | ||
12 | #include "qemu/osdep.h" | |
d96bf49b AB |
13 | #include "qemu/cutils.h" |
14 | #include "qemu/sockets.h" | |
15 | #include "exec/hwaddr.h" | |
16 | #include "exec/tb-flush.h" | |
ae7467b1 | 17 | #include "exec/gdbstub.h" |
c566080c | 18 | #include "gdbstub/syscalls.h" |
d96bf49b | 19 | #include "gdbstub/user.h" |
ae7467b1 | 20 | #include "hw/core/cpu.h" |
d96bf49b | 21 | #include "trace.h" |
ae7467b1 AB |
22 | #include "internals.h" |
23 | ||
d96bf49b AB |
24 | /* User-mode specific state */ |
25 | typedef struct { | |
26 | int fd; | |
27 | char *socket_path; | |
28 | int running_state; | |
29 | } GDBUserState; | |
30 | ||
31 | static GDBUserState gdbserver_user_state; | |
32 | ||
33 | int gdb_get_char(void) | |
34 | { | |
35 | uint8_t ch; | |
36 | int ret; | |
37 | ||
38 | for (;;) { | |
39 | ret = recv(gdbserver_user_state.fd, &ch, 1, 0); | |
40 | if (ret < 0) { | |
41 | if (errno == ECONNRESET) { | |
42 | gdbserver_user_state.fd = -1; | |
43 | } | |
44 | if (errno != EINTR) { | |
45 | return -1; | |
46 | } | |
47 | } else if (ret == 0) { | |
48 | close(gdbserver_user_state.fd); | |
49 | gdbserver_user_state.fd = -1; | |
50 | return -1; | |
51 | } else { | |
52 | break; | |
53 | } | |
54 | } | |
55 | return ch; | |
56 | } | |
57 | ||
a7e0f9bd AB |
58 | bool gdb_got_immediate_ack(void) |
59 | { | |
60 | int i; | |
61 | ||
62 | i = gdb_get_char(); | |
63 | if (i < 0) { | |
64 | /* no response, continue anyway */ | |
65 | return true; | |
66 | } | |
67 | ||
68 | if (i == '+') { | |
69 | /* received correctly, continue */ | |
70 | return true; | |
71 | } | |
72 | ||
73 | /* anything else, including '-' then try again */ | |
74 | return false; | |
75 | } | |
76 | ||
d96bf49b AB |
77 | void gdb_put_buffer(const uint8_t *buf, int len) |
78 | { | |
79 | int ret; | |
80 | ||
81 | while (len > 0) { | |
82 | ret = send(gdbserver_user_state.fd, buf, len, 0); | |
83 | if (ret < 0) { | |
84 | if (errno != EINTR) { | |
85 | return; | |
86 | } | |
87 | } else { | |
88 | buf += ret; | |
89 | len -= ret; | |
90 | } | |
91 | } | |
92 | } | |
93 | ||
94 | /* Tell the remote gdb that the process has exited. */ | |
95 | void gdb_exit(int code) | |
96 | { | |
97 | char buf[4]; | |
98 | ||
99 | if (!gdbserver_state.init) { | |
100 | return; | |
101 | } | |
102 | if (gdbserver_user_state.socket_path) { | |
103 | unlink(gdbserver_user_state.socket_path); | |
104 | } | |
105 | if (gdbserver_user_state.fd < 0) { | |
106 | return; | |
107 | } | |
108 | ||
109 | trace_gdbstub_op_exiting((uint8_t)code); | |
110 | ||
75837005 MTB |
111 | if (gdbserver_state.allow_stop_reply) { |
112 | snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code); | |
113 | gdb_put_packet(buf); | |
114 | gdbserver_state.allow_stop_reply = false; | |
115 | } | |
e216256a CC |
116 | |
117 | } | |
118 | ||
119 | void gdb_qemu_exit(int code) | |
120 | { | |
121 | exit(code); | |
d96bf49b AB |
122 | } |
123 | ||
124 | int gdb_handlesig(CPUState *cpu, int sig) | |
125 | { | |
126 | char buf[256]; | |
127 | int n; | |
128 | ||
129 | if (!gdbserver_state.init || gdbserver_user_state.fd < 0) { | |
130 | return sig; | |
131 | } | |
132 | ||
133 | /* disable single step if it was enabled */ | |
134 | cpu_single_step(cpu, 0); | |
135 | tb_flush(cpu); | |
136 | ||
137 | if (sig != 0) { | |
138 | gdb_set_stop_cpu(cpu); | |
75837005 MTB |
139 | if (gdbserver_state.allow_stop_reply) { |
140 | g_string_printf(gdbserver_state.str_buf, | |
141 | "T%02xthread:", gdb_target_signal_to_gdb(sig)); | |
142 | gdb_append_thread_id(cpu, gdbserver_state.str_buf); | |
143 | g_string_append_c(gdbserver_state.str_buf, ';'); | |
144 | gdb_put_strbuf(); | |
145 | gdbserver_state.allow_stop_reply = false; | |
146 | } | |
d96bf49b AB |
147 | } |
148 | /* | |
149 | * gdb_put_packet() might have detected that the peer terminated the | |
150 | * connection. | |
151 | */ | |
152 | if (gdbserver_user_state.fd < 0) { | |
153 | return sig; | |
154 | } | |
155 | ||
156 | sig = 0; | |
157 | gdbserver_state.state = RS_IDLE; | |
158 | gdbserver_user_state.running_state = 0; | |
159 | while (gdbserver_user_state.running_state == 0) { | |
160 | n = read(gdbserver_user_state.fd, buf, 256); | |
161 | if (n > 0) { | |
162 | int i; | |
163 | ||
164 | for (i = 0; i < n; i++) { | |
165 | gdb_read_byte(buf[i]); | |
166 | } | |
167 | } else { | |
168 | /* | |
169 | * XXX: Connection closed. Should probably wait for another | |
170 | * connection before continuing. | |
171 | */ | |
172 | if (n == 0) { | |
173 | close(gdbserver_user_state.fd); | |
174 | } | |
175 | gdbserver_user_state.fd = -1; | |
176 | return sig; | |
177 | } | |
178 | } | |
179 | sig = gdbserver_state.signal; | |
180 | gdbserver_state.signal = 0; | |
181 | return sig; | |
182 | } | |
183 | ||
184 | /* Tell the remote gdb that the process has exited due to SIG. */ | |
185 | void gdb_signalled(CPUArchState *env, int sig) | |
186 | { | |
187 | char buf[4]; | |
188 | ||
75837005 MTB |
189 | if (!gdbserver_state.init || gdbserver_user_state.fd < 0 || |
190 | !gdbserver_state.allow_stop_reply) { | |
d96bf49b AB |
191 | return; |
192 | } | |
193 | ||
194 | snprintf(buf, sizeof(buf), "X%02x", gdb_target_signal_to_gdb(sig)); | |
195 | gdb_put_packet(buf); | |
75837005 | 196 | gdbserver_state.allow_stop_reply = false; |
d96bf49b AB |
197 | } |
198 | ||
199 | static void gdb_accept_init(int fd) | |
200 | { | |
201 | gdb_init_gdbserver_state(); | |
202 | gdb_create_default_process(&gdbserver_state); | |
203 | gdbserver_state.processes[0].attached = true; | |
204 | gdbserver_state.c_cpu = gdb_first_attached_cpu(); | |
205 | gdbserver_state.g_cpu = gdbserver_state.c_cpu; | |
206 | gdbserver_user_state.fd = fd; | |
d96bf49b AB |
207 | } |
208 | ||
209 | static bool gdb_accept_socket(int gdb_fd) | |
210 | { | |
211 | int fd; | |
212 | ||
213 | for (;;) { | |
214 | fd = accept(gdb_fd, NULL, NULL); | |
215 | if (fd < 0 && errno != EINTR) { | |
216 | perror("accept socket"); | |
217 | return false; | |
218 | } else if (fd >= 0) { | |
219 | qemu_set_cloexec(fd); | |
220 | break; | |
221 | } | |
222 | } | |
223 | ||
224 | gdb_accept_init(fd); | |
225 | return true; | |
226 | } | |
227 | ||
228 | static int gdbserver_open_socket(const char *path) | |
229 | { | |
230 | struct sockaddr_un sockaddr = {}; | |
231 | int fd, ret; | |
232 | ||
233 | fd = socket(AF_UNIX, SOCK_STREAM, 0); | |
234 | if (fd < 0) { | |
235 | perror("create socket"); | |
236 | return -1; | |
237 | } | |
238 | ||
239 | sockaddr.sun_family = AF_UNIX; | |
240 | pstrcpy(sockaddr.sun_path, sizeof(sockaddr.sun_path) - 1, path); | |
241 | ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr)); | |
242 | if (ret < 0) { | |
243 | perror("bind socket"); | |
244 | close(fd); | |
245 | return -1; | |
246 | } | |
247 | ret = listen(fd, 1); | |
248 | if (ret < 0) { | |
249 | perror("listen socket"); | |
250 | close(fd); | |
251 | return -1; | |
252 | } | |
253 | ||
254 | return fd; | |
255 | } | |
256 | ||
257 | static bool gdb_accept_tcp(int gdb_fd) | |
258 | { | |
259 | struct sockaddr_in sockaddr = {}; | |
260 | socklen_t len; | |
261 | int fd; | |
262 | ||
263 | for (;;) { | |
264 | len = sizeof(sockaddr); | |
265 | fd = accept(gdb_fd, (struct sockaddr *)&sockaddr, &len); | |
266 | if (fd < 0 && errno != EINTR) { | |
267 | perror("accept"); | |
268 | return false; | |
269 | } else if (fd >= 0) { | |
270 | qemu_set_cloexec(fd); | |
271 | break; | |
272 | } | |
273 | } | |
274 | ||
275 | /* set short latency */ | |
276 | if (socket_set_nodelay(fd)) { | |
277 | perror("setsockopt"); | |
278 | close(fd); | |
279 | return false; | |
280 | } | |
281 | ||
282 | gdb_accept_init(fd); | |
283 | return true; | |
284 | } | |
285 | ||
286 | static int gdbserver_open_port(int port) | |
287 | { | |
288 | struct sockaddr_in sockaddr; | |
289 | int fd, ret; | |
290 | ||
291 | fd = socket(PF_INET, SOCK_STREAM, 0); | |
292 | if (fd < 0) { | |
293 | perror("socket"); | |
294 | return -1; | |
295 | } | |
296 | qemu_set_cloexec(fd); | |
297 | ||
298 | socket_set_fast_reuse(fd); | |
299 | ||
300 | sockaddr.sin_family = AF_INET; | |
301 | sockaddr.sin_port = htons(port); | |
302 | sockaddr.sin_addr.s_addr = 0; | |
303 | ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr)); | |
304 | if (ret < 0) { | |
305 | perror("bind"); | |
306 | close(fd); | |
307 | return -1; | |
308 | } | |
309 | ret = listen(fd, 1); | |
310 | if (ret < 0) { | |
311 | perror("listen"); | |
312 | close(fd); | |
313 | return -1; | |
314 | } | |
315 | ||
316 | return fd; | |
317 | } | |
318 | ||
319 | int gdbserver_start(const char *port_or_path) | |
320 | { | |
321 | int port = g_ascii_strtoull(port_or_path, NULL, 10); | |
322 | int gdb_fd; | |
323 | ||
324 | if (port > 0) { | |
325 | gdb_fd = gdbserver_open_port(port); | |
326 | } else { | |
327 | gdb_fd = gdbserver_open_socket(port_or_path); | |
328 | } | |
329 | ||
330 | if (gdb_fd < 0) { | |
331 | return -1; | |
332 | } | |
333 | ||
334 | if (port > 0 && gdb_accept_tcp(gdb_fd)) { | |
335 | return 0; | |
336 | } else if (gdb_accept_socket(gdb_fd)) { | |
337 | gdbserver_user_state.socket_path = g_strdup(port_or_path); | |
338 | return 0; | |
339 | } | |
340 | ||
341 | /* gone wrong */ | |
342 | close(gdb_fd); | |
343 | return -1; | |
344 | } | |
345 | ||
346 | /* Disable gdb stub for child processes. */ | |
347 | void gdbserver_fork(CPUState *cpu) | |
348 | { | |
349 | if (!gdbserver_state.init || gdbserver_user_state.fd < 0) { | |
350 | return; | |
351 | } | |
352 | close(gdbserver_user_state.fd); | |
353 | gdbserver_user_state.fd = -1; | |
354 | cpu_breakpoint_remove_all(cpu, BP_GDB); | |
355 | /* no cpu_watchpoint_remove_all for user-mode */ | |
356 | } | |
357 | ||
358 | /* | |
359 | * Execution state helpers | |
360 | */ | |
361 | ||
8a2025b3 AB |
362 | void gdb_handle_query_attached(GArray *params, void *user_ctx) |
363 | { | |
364 | gdb_put_packet("0"); | |
365 | } | |
366 | ||
d96bf49b AB |
367 | void gdb_continue(void) |
368 | { | |
369 | gdbserver_user_state.running_state = 1; | |
370 | trace_gdbstub_op_continue(); | |
371 | } | |
372 | ||
373 | /* | |
374 | * Resume execution, for user-mode emulation it's equivalent to | |
375 | * gdb_continue. | |
376 | */ | |
377 | int gdb_continue_partial(char *newstates) | |
378 | { | |
379 | CPUState *cpu; | |
380 | int res = 0; | |
381 | /* | |
382 | * This is not exactly accurate, but it's an improvement compared to the | |
383 | * previous situation, where only one CPU would be single-stepped. | |
384 | */ | |
385 | CPU_FOREACH(cpu) { | |
386 | if (newstates[cpu->cpu_index] == 's') { | |
387 | trace_gdbstub_op_stepping(cpu->cpu_index); | |
388 | cpu_single_step(cpu, gdbserver_state.sstep_flags); | |
389 | } | |
390 | } | |
391 | gdbserver_user_state.running_state = 1; | |
392 | return res; | |
393 | } | |
394 | ||
589a5867 AB |
395 | /* |
396 | * Memory access helpers | |
397 | */ | |
398 | int gdb_target_memory_rw_debug(CPUState *cpu, hwaddr addr, | |
399 | uint8_t *buf, int len, bool is_write) | |
400 | { | |
401 | CPUClass *cc; | |
402 | ||
403 | cc = CPU_GET_CLASS(cpu); | |
404 | if (cc->memory_rw_debug) { | |
405 | return cc->memory_rw_debug(cpu, addr, buf, len, is_write); | |
406 | } | |
407 | return cpu_memory_rw_debug(cpu, addr, buf, len, is_write); | |
408 | } | |
409 | ||
7ea0c33d AB |
410 | /* |
411 | * cpu helpers | |
412 | */ | |
413 | ||
414 | unsigned int gdb_get_max_cpus(void) | |
415 | { | |
416 | CPUState *cpu; | |
417 | unsigned int max_cpus = 1; | |
418 | ||
419 | CPU_FOREACH(cpu) { | |
420 | max_cpus = max_cpus <= cpu->cpu_index ? cpu->cpu_index + 1 : max_cpus; | |
421 | } | |
422 | ||
423 | return max_cpus; | |
424 | } | |
425 | ||
505601d5 AB |
426 | /* replay not supported for user-mode */ |
427 | bool gdb_can_reverse(void) | |
428 | { | |
429 | return false; | |
430 | } | |
7ea0c33d | 431 | |
d96bf49b AB |
432 | /* |
433 | * Break/Watch point helpers | |
434 | */ | |
435 | ||
a48e7d9e AB |
436 | bool gdb_supports_guest_debug(void) |
437 | { | |
438 | /* user-mode == TCG == supported */ | |
439 | return true; | |
440 | } | |
441 | ||
55b5b8e9 | 442 | int gdb_breakpoint_insert(CPUState *cs, int type, vaddr addr, vaddr len) |
ae7467b1 AB |
443 | { |
444 | CPUState *cpu; | |
445 | int err = 0; | |
446 | ||
447 | switch (type) { | |
448 | case GDB_BREAKPOINT_SW: | |
449 | case GDB_BREAKPOINT_HW: | |
450 | CPU_FOREACH(cpu) { | |
451 | err = cpu_breakpoint_insert(cpu, addr, BP_GDB, NULL); | |
452 | if (err) { | |
453 | break; | |
454 | } | |
455 | } | |
456 | return err; | |
457 | default: | |
458 | /* user-mode doesn't support watchpoints */ | |
459 | return -ENOSYS; | |
460 | } | |
461 | } | |
462 | ||
55b5b8e9 | 463 | int gdb_breakpoint_remove(CPUState *cs, int type, vaddr addr, vaddr len) |
ae7467b1 AB |
464 | { |
465 | CPUState *cpu; | |
466 | int err = 0; | |
467 | ||
468 | switch (type) { | |
469 | case GDB_BREAKPOINT_SW: | |
470 | case GDB_BREAKPOINT_HW: | |
471 | CPU_FOREACH(cpu) { | |
472 | err = cpu_breakpoint_remove(cpu, addr, BP_GDB); | |
473 | if (err) { | |
474 | break; | |
475 | } | |
476 | } | |
477 | return err; | |
478 | default: | |
479 | /* user-mode doesn't support watchpoints */ | |
480 | return -ENOSYS; | |
481 | } | |
482 | } | |
483 | ||
484 | void gdb_breakpoint_remove_all(CPUState *cs) | |
485 | { | |
486 | cpu_breakpoint_remove_all(cs, BP_GDB); | |
487 | } | |
131f387d AB |
488 | |
489 | /* | |
490 | * For user-mode syscall support we send the system call immediately | |
491 | * and then return control to gdb for it to process the syscall request. | |
492 | * Since the protocol requires that gdb hands control back to us | |
493 | * using a "here are the results" F packet, we don't need to check | |
494 | * gdb_handlesig's return value (which is the signal to deliver if | |
495 | * execution was resumed via a continue packet). | |
496 | */ | |
497 | void gdb_syscall_handling(const char *syscall_packet) | |
498 | { | |
499 | gdb_put_packet(syscall_packet); | |
500 | gdb_handlesig(gdbserver_state.c_cpu, 0); | |
501 | } |