1 | /* |
2 | * os-posix-lib.c |
3 | * |
4 | * Copyright (c) 2003-2008 Fabrice Bellard |
5 | * Copyright (c) 2010 Red Hat, Inc. |
6 | * |
7 | * QEMU library functions on POSIX which are shared between QEMU and |
8 | * the QEMU tools. |
9 | * |
10 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
11 | * of this software and associated documentation files (the "Software"), to deal |
12 | * in the Software without restriction, including without limitation the rights |
13 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
14 | * copies of the Software, and to permit persons to whom the Software is |
15 | * furnished to do so, subject to the following conditions: |
16 | * |
17 | * The above copyright notice and this permission notice shall be included in |
18 | * all copies or substantial portions of the Software. |
19 | * |
20 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
21 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
22 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
23 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
24 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
25 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
26 | * THE SOFTWARE. |
27 | */ |
28 | |
29 | #include "qemu/osdep.h" |
30 | #include <termios.h> |
31 | |
32 | #include <glib/gprintf.h> |
33 | |
34 | #include "qemu-common.h" |
35 | #include "sysemu/sysemu.h" |
36 | #include "trace.h" |
37 | #include "qapi/error.h" |
38 | #include "qemu/sockets.h" |
39 | #include "qemu/thread.h" |
40 | #include <libgen.h> |
41 | #include <sys/signal.h> |
42 | #include "qemu/cutils.h" |
43 | |
44 | #ifdef CONFIG_LINUX |
45 | #include <sys/syscall.h> |
46 | #endif |
47 | |
48 | #ifdef __FreeBSD__ |
49 | #include <sys/sysctl.h> |
50 | #include <sys/user.h> |
51 | #include <libutil.h> |
52 | #endif |
53 | |
54 | #ifdef __NetBSD__ |
55 | #include <sys/sysctl.h> |
56 | #endif |
57 | |
58 | #include "qemu/mmap-alloc.h" |
59 | |
60 | #ifdef CONFIG_DEBUG_STACK_USAGE |
61 | #include "qemu/error-report.h" |
62 | #endif |
63 | |
64 | #define MAX_MEM_PREALLOC_THREAD_COUNT 16 |
65 | |
66 | struct MemsetThread { |
67 | char *addr; |
68 | size_t numpages; |
69 | size_t hpagesize; |
70 | QemuThread pgthread; |
71 | sigjmp_buf env; |
72 | }; |
73 | typedef struct MemsetThread MemsetThread; |
74 | |
75 | static MemsetThread *memset_thread; |
76 | static int memset_num_threads; |
77 | static bool memset_thread_failed; |
78 | |
79 | int qemu_get_thread_id(void) |
80 | { |
81 | #if defined(__linux__) |
82 | return syscall(SYS_gettid); |
83 | #else |
84 | return getpid(); |
85 | #endif |
86 | } |
87 | |
88 | int qemu_daemon(int nochdir, int noclose) |
89 | { |
90 | return daemon(nochdir, noclose); |
91 | } |
92 | |
93 | bool qemu_write_pidfile(const char *path, Error **errp) |
94 | { |
95 | int fd; |
96 | char pidstr[32]; |
97 | |
98 | while (1) { |
99 | struct stat a, b; |
100 | struct flock lock = { |
101 | .l_type = F_WRLCK, |
102 | .l_whence = SEEK_SET, |
103 | .l_len = 0, |
104 | }; |
105 | |
106 | fd = qemu_open(path, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR); |
107 | if (fd == -1) { |
108 | error_setg_errno(errp, errno, "Cannot open pid file" ); |
109 | return false; |
110 | } |
111 | |
112 | if (fstat(fd, &b) < 0) { |
113 | error_setg_errno(errp, errno, "Cannot stat file" ); |
114 | goto fail_close; |
115 | } |
116 | |
117 | if (fcntl(fd, F_SETLK, &lock)) { |
118 | error_setg_errno(errp, errno, "Cannot lock pid file" ); |
119 | goto fail_close; |
120 | } |
121 | |
122 | /* |
123 | * Now make sure the path we locked is the same one that now |
124 | * exists on the filesystem. |
125 | */ |
126 | if (stat(path, &a) < 0) { |
127 | /* |
128 | * PID file disappeared, someone else must be racing with |
129 | * us, so try again. |
130 | */ |
131 | close(fd); |
132 | continue; |
133 | } |
134 | |
135 | if (a.st_ino == b.st_ino) { |
136 | break; |
137 | } |
138 | |
139 | /* |
140 | * PID file was recreated, someone else must be racing with |
141 | * us, so try again. |
142 | */ |
143 | close(fd); |
144 | } |
145 | |
146 | if (ftruncate(fd, 0) < 0) { |
147 | error_setg_errno(errp, errno, "Failed to truncate pid file" ); |
148 | goto fail_unlink; |
149 | } |
150 | |
151 | snprintf(pidstr, sizeof(pidstr), FMT_pid "\n" , getpid()); |
152 | if (write(fd, pidstr, strlen(pidstr)) != strlen(pidstr)) { |
153 | error_setg(errp, "Failed to write pid file" ); |
154 | goto fail_unlink; |
155 | } |
156 | |
157 | return true; |
158 | |
159 | fail_unlink: |
160 | unlink(path); |
161 | fail_close: |
162 | close(fd); |
163 | return false; |
164 | } |
165 | |
166 | void *qemu_oom_check(void *ptr) |
167 | { |
168 | if (ptr == NULL) { |
169 | fprintf(stderr, "Failed to allocate memory: %s\n" , strerror(errno)); |
170 | abort(); |
171 | } |
172 | return ptr; |
173 | } |
174 | |
175 | void *qemu_try_memalign(size_t alignment, size_t size) |
176 | { |
177 | void *ptr; |
178 | |
179 | if (alignment < sizeof(void*)) { |
180 | alignment = sizeof(void*); |
181 | } |
182 | |
183 | #if defined(CONFIG_POSIX_MEMALIGN) |
184 | int ret; |
185 | ret = posix_memalign(&ptr, alignment, size); |
186 | if (ret != 0) { |
187 | errno = ret; |
188 | ptr = NULL; |
189 | } |
190 | #elif defined(CONFIG_BSD) |
191 | ptr = valloc(size); |
192 | #else |
193 | ptr = memalign(alignment, size); |
194 | #endif |
195 | trace_qemu_memalign(alignment, size, ptr); |
196 | return ptr; |
197 | } |
198 | |
199 | void *qemu_memalign(size_t alignment, size_t size) |
200 | { |
201 | return qemu_oom_check(qemu_try_memalign(alignment, size)); |
202 | } |
203 | |
204 | /* alloc shared memory pages */ |
205 | void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared) |
206 | { |
207 | size_t align = QEMU_VMALLOC_ALIGN; |
208 | void *ptr = qemu_ram_mmap(-1, size, align, shared, false); |
209 | |
210 | if (ptr == MAP_FAILED) { |
211 | return NULL; |
212 | } |
213 | |
214 | if (alignment) { |
215 | *alignment = align; |
216 | } |
217 | |
218 | trace_qemu_anon_ram_alloc(size, ptr); |
219 | return ptr; |
220 | } |
221 | |
222 | void qemu_vfree(void *ptr) |
223 | { |
224 | trace_qemu_vfree(ptr); |
225 | free(ptr); |
226 | } |
227 | |
228 | void qemu_anon_ram_free(void *ptr, size_t size) |
229 | { |
230 | trace_qemu_anon_ram_free(ptr, size); |
231 | qemu_ram_munmap(-1, ptr, size); |
232 | } |
233 | |
234 | void qemu_set_block(int fd) |
235 | { |
236 | int f; |
237 | f = fcntl(fd, F_GETFL); |
238 | assert(f != -1); |
239 | f = fcntl(fd, F_SETFL, f & ~O_NONBLOCK); |
240 | assert(f != -1); |
241 | } |
242 | |
243 | void qemu_set_nonblock(int fd) |
244 | { |
245 | int f; |
246 | f = fcntl(fd, F_GETFL); |
247 | assert(f != -1); |
248 | f = fcntl(fd, F_SETFL, f | O_NONBLOCK); |
249 | #ifdef __OpenBSD__ |
250 | if (f == -1) { |
251 | /* |
252 | * Previous to OpenBSD 6.3, fcntl(F_SETFL) is not permitted on |
253 | * memory devices and sets errno to ENODEV. |
254 | * It's OK if we fail to set O_NONBLOCK on devices like /dev/null, |
255 | * because they will never block anyway. |
256 | */ |
257 | assert(errno == ENODEV); |
258 | } |
259 | #else |
260 | assert(f != -1); |
261 | #endif |
262 | } |
263 | |
264 | int socket_set_fast_reuse(int fd) |
265 | { |
266 | int val = 1, ret; |
267 | |
268 | ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, |
269 | (const char *)&val, sizeof(val)); |
270 | |
271 | assert(ret == 0); |
272 | |
273 | return ret; |
274 | } |
275 | |
276 | void qemu_set_cloexec(int fd) |
277 | { |
278 | int f; |
279 | f = fcntl(fd, F_GETFD); |
280 | assert(f != -1); |
281 | f = fcntl(fd, F_SETFD, f | FD_CLOEXEC); |
282 | assert(f != -1); |
283 | } |
284 | |
285 | /* |
286 | * Creates a pipe with FD_CLOEXEC set on both file descriptors |
287 | */ |
288 | int qemu_pipe(int pipefd[2]) |
289 | { |
290 | int ret; |
291 | |
292 | #ifdef CONFIG_PIPE2 |
293 | ret = pipe2(pipefd, O_CLOEXEC); |
294 | if (ret != -1 || errno != ENOSYS) { |
295 | return ret; |
296 | } |
297 | #endif |
298 | ret = pipe(pipefd); |
299 | if (ret == 0) { |
300 | qemu_set_cloexec(pipefd[0]); |
301 | qemu_set_cloexec(pipefd[1]); |
302 | } |
303 | |
304 | return ret; |
305 | } |
306 | |
307 | char * |
308 | qemu_get_local_state_pathname(const char *relative_pathname) |
309 | { |
310 | return g_strdup_printf("%s/%s" , CONFIG_QEMU_LOCALSTATEDIR, |
311 | relative_pathname); |
312 | } |
313 | |
314 | void qemu_set_tty_echo(int fd, bool echo) |
315 | { |
316 | struct termios tty; |
317 | |
318 | tcgetattr(fd, &tty); |
319 | |
320 | if (echo) { |
321 | tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; |
322 | } else { |
323 | tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); |
324 | } |
325 | |
326 | tcsetattr(fd, TCSANOW, &tty); |
327 | } |
328 | |
329 | static char exec_dir[PATH_MAX]; |
330 | |
331 | void qemu_init_exec_dir(const char *argv0) |
332 | { |
333 | char *dir; |
334 | char *p = NULL; |
335 | char buf[PATH_MAX]; |
336 | |
337 | assert(!exec_dir[0]); |
338 | |
339 | #if defined(__linux__) |
340 | { |
341 | int len; |
342 | len = readlink("/proc/self/exe" , buf, sizeof(buf) - 1); |
343 | if (len > 0) { |
344 | buf[len] = 0; |
345 | p = buf; |
346 | } |
347 | } |
348 | #elif defined(__FreeBSD__) \ |
349 | || (defined(__NetBSD__) && defined(KERN_PROC_PATHNAME)) |
350 | { |
351 | #if defined(__FreeBSD__) |
352 | static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; |
353 | #else |
354 | static int mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME}; |
355 | #endif |
356 | size_t len = sizeof(buf) - 1; |
357 | |
358 | *buf = '\0'; |
359 | if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && |
360 | *buf) { |
361 | buf[sizeof(buf) - 1] = '\0'; |
362 | p = buf; |
363 | } |
364 | } |
365 | #endif |
366 | /* If we don't have any way of figuring out the actual executable |
367 | location then try argv[0]. */ |
368 | if (!p) { |
369 | if (!argv0) { |
370 | return; |
371 | } |
372 | p = realpath(argv0, buf); |
373 | if (!p) { |
374 | return; |
375 | } |
376 | } |
377 | dir = g_path_get_dirname(p); |
378 | |
379 | pstrcpy(exec_dir, sizeof(exec_dir), dir); |
380 | |
381 | g_free(dir); |
382 | } |
383 | |
384 | char *qemu_get_exec_dir(void) |
385 | { |
386 | return g_strdup(exec_dir); |
387 | } |
388 | |
389 | static void sigbus_handler(int signal) |
390 | { |
391 | int i; |
392 | if (memset_thread) { |
393 | for (i = 0; i < memset_num_threads; i++) { |
394 | if (qemu_thread_is_self(&memset_thread[i].pgthread)) { |
395 | siglongjmp(memset_thread[i].env, 1); |
396 | } |
397 | } |
398 | } |
399 | } |
400 | |
401 | static void *do_touch_pages(void *arg) |
402 | { |
403 | MemsetThread *memset_args = (MemsetThread *)arg; |
404 | sigset_t set, oldset; |
405 | |
406 | /* unblock SIGBUS */ |
407 | sigemptyset(&set); |
408 | sigaddset(&set, SIGBUS); |
409 | pthread_sigmask(SIG_UNBLOCK, &set, &oldset); |
410 | |
411 | if (sigsetjmp(memset_args->env, 1)) { |
412 | memset_thread_failed = true; |
413 | } else { |
414 | char *addr = memset_args->addr; |
415 | size_t numpages = memset_args->numpages; |
416 | size_t hpagesize = memset_args->hpagesize; |
417 | size_t i; |
418 | for (i = 0; i < numpages; i++) { |
419 | /* |
420 | * Read & write back the same value, so we don't |
421 | * corrupt existing user/app data that might be |
422 | * stored. |
423 | * |
424 | * 'volatile' to stop compiler optimizing this away |
425 | * to a no-op |
426 | * |
427 | * TODO: get a better solution from kernel so we |
428 | * don't need to write at all so we don't cause |
429 | * wear on the storage backing the region... |
430 | */ |
431 | *(volatile char *)addr = *addr; |
432 | addr += hpagesize; |
433 | } |
434 | } |
435 | pthread_sigmask(SIG_SETMASK, &oldset, NULL); |
436 | return NULL; |
437 | } |
438 | |
439 | static inline int get_memset_num_threads(int smp_cpus) |
440 | { |
441 | long host_procs = sysconf(_SC_NPROCESSORS_ONLN); |
442 | int ret = 1; |
443 | |
444 | if (host_procs > 0) { |
445 | ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); |
446 | } |
447 | /* In case sysconf() fails, we fall back to single threaded */ |
448 | return ret; |
449 | } |
450 | |
451 | static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages, |
452 | int smp_cpus) |
453 | { |
454 | size_t numpages_per_thread; |
455 | size_t size_per_thread; |
456 | char *addr = area; |
457 | int i = 0; |
458 | |
459 | memset_thread_failed = false; |
460 | memset_num_threads = get_memset_num_threads(smp_cpus); |
461 | memset_thread = g_new0(MemsetThread, memset_num_threads); |
462 | numpages_per_thread = (numpages / memset_num_threads); |
463 | size_per_thread = (hpagesize * numpages_per_thread); |
464 | for (i = 0; i < memset_num_threads; i++) { |
465 | memset_thread[i].addr = addr; |
466 | memset_thread[i].numpages = (i == (memset_num_threads - 1)) ? |
467 | numpages : numpages_per_thread; |
468 | memset_thread[i].hpagesize = hpagesize; |
469 | qemu_thread_create(&memset_thread[i].pgthread, "touch_pages" , |
470 | do_touch_pages, &memset_thread[i], |
471 | QEMU_THREAD_JOINABLE); |
472 | addr += size_per_thread; |
473 | numpages -= numpages_per_thread; |
474 | } |
475 | for (i = 0; i < memset_num_threads; i++) { |
476 | qemu_thread_join(&memset_thread[i].pgthread); |
477 | } |
478 | g_free(memset_thread); |
479 | memset_thread = NULL; |
480 | |
481 | return memset_thread_failed; |
482 | } |
483 | |
484 | void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, |
485 | Error **errp) |
486 | { |
487 | int ret; |
488 | struct sigaction act, oldact; |
489 | size_t hpagesize = qemu_fd_getpagesize(fd); |
490 | size_t numpages = DIV_ROUND_UP(memory, hpagesize); |
491 | |
492 | memset(&act, 0, sizeof(act)); |
493 | act.sa_handler = &sigbus_handler; |
494 | act.sa_flags = 0; |
495 | |
496 | ret = sigaction(SIGBUS, &act, &oldact); |
497 | if (ret) { |
498 | error_setg_errno(errp, errno, |
499 | "os_mem_prealloc: failed to install signal handler" ); |
500 | return; |
501 | } |
502 | |
503 | /* touch pages simultaneously */ |
504 | if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) { |
505 | error_setg(errp, "os_mem_prealloc: Insufficient free host memory " |
506 | "pages available to allocate guest RAM" ); |
507 | } |
508 | |
509 | ret = sigaction(SIGBUS, &oldact, NULL); |
510 | if (ret) { |
511 | /* Terminate QEMU since it can't recover from error */ |
512 | perror("os_mem_prealloc: failed to reinstall signal handler" ); |
513 | exit(1); |
514 | } |
515 | } |
516 | |
517 | uint64_t qemu_get_pmem_size(const char *filename, Error **errp) |
518 | { |
519 | struct stat st; |
520 | |
521 | if (stat(filename, &st) < 0) { |
522 | error_setg(errp, "unable to stat pmem file \"%s\"" , filename); |
523 | return 0; |
524 | } |
525 | |
526 | #if defined(__linux__) |
527 | /* Special handling for devdax character devices */ |
528 | if (S_ISCHR(st.st_mode)) { |
529 | char *subsystem_path = NULL; |
530 | char *subsystem = NULL; |
531 | char *size_path = NULL; |
532 | char *size_str = NULL; |
533 | uint64_t ret = 0; |
534 | |
535 | subsystem_path = g_strdup_printf("/sys/dev/char/%d:%d/subsystem" , |
536 | major(st.st_rdev), minor(st.st_rdev)); |
537 | subsystem = g_file_read_link(subsystem_path, NULL); |
538 | if (!subsystem) { |
539 | error_setg(errp, "unable to read subsystem for pmem file \"%s\"" , |
540 | filename); |
541 | goto devdax_err; |
542 | } |
543 | |
544 | if (!g_str_has_suffix(subsystem, "/dax" )) { |
545 | error_setg(errp, "pmem file \"%s\" is not a dax device" , filename); |
546 | goto devdax_err; |
547 | } |
548 | |
549 | size_path = g_strdup_printf("/sys/dev/char/%d:%d/size" , |
550 | major(st.st_rdev), minor(st.st_rdev)); |
551 | if (!g_file_get_contents(size_path, &size_str, NULL, NULL)) { |
552 | error_setg(errp, "unable to read size for pmem file \"%s\"" , |
553 | size_path); |
554 | goto devdax_err; |
555 | } |
556 | |
557 | ret = g_ascii_strtoull(size_str, NULL, 0); |
558 | |
559 | devdax_err: |
560 | g_free(size_str); |
561 | g_free(size_path); |
562 | g_free(subsystem); |
563 | g_free(subsystem_path); |
564 | return ret; |
565 | } |
566 | #endif /* defined(__linux__) */ |
567 | |
568 | return st.st_size; |
569 | } |
570 | |
571 | char *qemu_get_pid_name(pid_t pid) |
572 | { |
573 | char *name = NULL; |
574 | |
575 | #if defined(__FreeBSD__) |
576 | /* BSDs don't have /proc, but they provide a nice substitute */ |
577 | struct kinfo_proc *proc = kinfo_getproc(pid); |
578 | |
579 | if (proc) { |
580 | name = g_strdup(proc->ki_comm); |
581 | free(proc); |
582 | } |
583 | #else |
584 | /* Assume a system with reasonable procfs */ |
585 | char *pid_path; |
586 | size_t len; |
587 | |
588 | pid_path = g_strdup_printf("/proc/%d/cmdline" , pid); |
589 | g_file_get_contents(pid_path, &name, &len, NULL); |
590 | g_free(pid_path); |
591 | #endif |
592 | |
593 | return name; |
594 | } |
595 | |
596 | |
597 | pid_t qemu_fork(Error **errp) |
598 | { |
599 | sigset_t oldmask, newmask; |
600 | struct sigaction sig_action; |
601 | int saved_errno; |
602 | pid_t pid; |
603 | |
604 | /* |
605 | * Need to block signals now, so that child process can safely |
606 | * kill off caller's signal handlers without a race. |
607 | */ |
608 | sigfillset(&newmask); |
609 | if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) { |
610 | error_setg_errno(errp, errno, |
611 | "cannot block signals" ); |
612 | return -1; |
613 | } |
614 | |
615 | pid = fork(); |
616 | saved_errno = errno; |
617 | |
618 | if (pid < 0) { |
619 | /* attempt to restore signal mask, but ignore failure, to |
620 | * avoid obscuring the fork failure */ |
621 | (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); |
622 | error_setg_errno(errp, saved_errno, |
623 | "cannot fork child process" ); |
624 | errno = saved_errno; |
625 | return -1; |
626 | } else if (pid) { |
627 | /* parent process */ |
628 | |
629 | /* Restore our original signal mask now that the child is |
630 | * safely running. Only documented failures are EFAULT (not |
631 | * possible, since we are using just-grabbed mask) or EINVAL |
632 | * (not possible, since we are using correct arguments). */ |
633 | (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); |
634 | } else { |
635 | /* child process */ |
636 | size_t i; |
637 | |
638 | /* Clear out all signal handlers from parent so nothing |
639 | * unexpected can happen in our child once we unblock |
640 | * signals */ |
641 | sig_action.sa_handler = SIG_DFL; |
642 | sig_action.sa_flags = 0; |
643 | sigemptyset(&sig_action.sa_mask); |
644 | |
645 | for (i = 1; i < NSIG; i++) { |
646 | /* Only possible errors are EFAULT or EINVAL The former |
647 | * won't happen, the latter we expect, so no need to check |
648 | * return value */ |
649 | (void)sigaction(i, &sig_action, NULL); |
650 | } |
651 | |
652 | /* Unmask all signals in child, since we've no idea what the |
653 | * caller's done with their signal mask and don't want to |
654 | * propagate that to children */ |
655 | sigemptyset(&newmask); |
656 | if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) { |
657 | Error *local_err = NULL; |
658 | error_setg_errno(&local_err, errno, |
659 | "cannot unblock signals" ); |
660 | error_report_err(local_err); |
661 | _exit(1); |
662 | } |
663 | } |
664 | return pid; |
665 | } |
666 | |
667 | void *qemu_alloc_stack(size_t *sz) |
668 | { |
669 | void *ptr, *guardpage; |
670 | int flags; |
671 | #ifdef CONFIG_DEBUG_STACK_USAGE |
672 | void *ptr2; |
673 | #endif |
674 | size_t pagesz = getpagesize(); |
675 | #ifdef _SC_THREAD_STACK_MIN |
676 | /* avoid stacks smaller than _SC_THREAD_STACK_MIN */ |
677 | long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN); |
678 | *sz = MAX(MAX(min_stack_sz, 0), *sz); |
679 | #endif |
680 | /* adjust stack size to a multiple of the page size */ |
681 | *sz = ROUND_UP(*sz, pagesz); |
682 | /* allocate one extra page for the guard page */ |
683 | *sz += pagesz; |
684 | |
685 | flags = MAP_PRIVATE | MAP_ANONYMOUS; |
686 | #if defined(MAP_STACK) && defined(__OpenBSD__) |
687 | /* Only enable MAP_STACK on OpenBSD. Other OS's such as |
688 | * Linux/FreeBSD/NetBSD have a flag with the same name |
689 | * but have differing functionality. OpenBSD will SEGV |
690 | * if it spots execution with a stack pointer pointing |
691 | * at memory that was not allocated with MAP_STACK. |
692 | */ |
693 | flags |= MAP_STACK; |
694 | #endif |
695 | |
696 | ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, flags, -1, 0); |
697 | if (ptr == MAP_FAILED) { |
698 | perror("failed to allocate memory for stack" ); |
699 | abort(); |
700 | } |
701 | |
702 | #if defined(HOST_IA64) |
703 | /* separate register stack */ |
704 | guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz); |
705 | #elif defined(HOST_HPPA) |
706 | /* stack grows up */ |
707 | guardpage = ptr + *sz - pagesz; |
708 | #else |
709 | /* stack grows down */ |
710 | guardpage = ptr; |
711 | #endif |
712 | if (mprotect(guardpage, pagesz, PROT_NONE) != 0) { |
713 | perror("failed to set up stack guard page" ); |
714 | abort(); |
715 | } |
716 | |
717 | #ifdef CONFIG_DEBUG_STACK_USAGE |
718 | for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) { |
719 | *(uint32_t *)ptr2 = 0xdeadbeaf; |
720 | } |
721 | #endif |
722 | |
723 | return ptr; |
724 | } |
725 | |
726 | #ifdef CONFIG_DEBUG_STACK_USAGE |
727 | static __thread unsigned int max_stack_usage; |
728 | #endif |
729 | |
730 | void qemu_free_stack(void *stack, size_t sz) |
731 | { |
732 | #ifdef CONFIG_DEBUG_STACK_USAGE |
733 | unsigned int usage; |
734 | void *ptr; |
735 | |
736 | for (ptr = stack + getpagesize(); ptr < stack + sz; |
737 | ptr += sizeof(uint32_t)) { |
738 | if (*(uint32_t *)ptr != 0xdeadbeaf) { |
739 | break; |
740 | } |
741 | } |
742 | usage = sz - (uintptr_t) (ptr - stack); |
743 | if (usage > max_stack_usage) { |
744 | error_report("thread %d max stack usage increased from %u to %u" , |
745 | qemu_get_thread_id(), max_stack_usage, usage); |
746 | max_stack_usage = usage; |
747 | } |
748 | #endif |
749 | |
750 | munmap(stack, sz); |
751 | } |
752 | |
753 | void sigaction_invoke(struct sigaction *action, |
754 | struct qemu_signalfd_siginfo *info) |
755 | { |
756 | siginfo_t si = {}; |
757 | si.si_signo = info->ssi_signo; |
758 | si.si_errno = info->ssi_errno; |
759 | si.si_code = info->ssi_code; |
760 | |
761 | /* Convert the minimal set of fields defined by POSIX. |
762 | * Positive si_code values are reserved for kernel-generated |
763 | * signals, where the valid siginfo fields are determined by |
764 | * the signal number. But according to POSIX, it is unspecified |
765 | * whether SI_USER and SI_QUEUE have values less than or equal to |
766 | * zero. |
767 | */ |
768 | if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE || |
769 | info->ssi_code <= 0) { |
770 | /* SIGTERM, etc. */ |
771 | si.si_pid = info->ssi_pid; |
772 | si.si_uid = info->ssi_uid; |
773 | } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE || |
774 | info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) { |
775 | si.si_addr = (void *)(uintptr_t)info->ssi_addr; |
776 | } else if (info->ssi_signo == SIGCHLD) { |
777 | si.si_pid = info->ssi_pid; |
778 | si.si_status = info->ssi_status; |
779 | si.si_uid = info->ssi_uid; |
780 | } |
781 | action->sa_sigaction(info->ssi_signo, &si, NULL); |
782 | } |
783 | |