oslib-posix: default exec_dir to bindir
[qemu.git] / util / oslib-posix.c
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 "qemu/cutils.h"
42
43 #ifdef CONFIG_LINUX
44 #include <sys/syscall.h>
45 #endif
46
47 #ifdef __FreeBSD__
48 #include <sys/sysctl.h>
49 #include <sys/user.h>
50 #include <sys/thr.h>
51 #include <libutil.h>
52 #endif
53
54 #ifdef __NetBSD__
55 #include <sys/sysctl.h>
56 #include <lwp.h>
57 #endif
58
59 #ifdef __APPLE__
60 #include <mach-o/dyld.h>
61 #endif
62
63 #ifdef __HAIKU__
64 #include <kernel/image.h>
65 #endif
66
67 #include "qemu/mmap-alloc.h"
68
69 #ifdef CONFIG_DEBUG_STACK_USAGE
70 #include "qemu/error-report.h"
71 #endif
72
73 #define MAX_MEM_PREALLOC_THREAD_COUNT 16
74
75 struct MemsetThread {
76 char *addr;
77 size_t numpages;
78 size_t hpagesize;
79 QemuThread pgthread;
80 sigjmp_buf env;
81 };
82 typedef struct MemsetThread MemsetThread;
83
84 static MemsetThread *memset_thread;
85 static int memset_num_threads;
86 static bool memset_thread_failed;
87
88 static QemuMutex page_mutex;
89 static QemuCond page_cond;
90 static bool threads_created_flag;
91
92 int qemu_get_thread_id(void)
93 {
94 #if defined(__linux__)
95 return syscall(SYS_gettid);
96 #elif defined(__FreeBSD__)
97 /* thread id is up to INT_MAX */
98 long tid;
99 thr_self(&tid);
100 return (int)tid;
101 #elif defined(__NetBSD__)
102 return _lwp_self();
103 #elif defined(__OpenBSD__)
104 return getthrid();
105 #else
106 return getpid();
107 #endif
108 }
109
110 int qemu_daemon(int nochdir, int noclose)
111 {
112 return daemon(nochdir, noclose);
113 }
114
115 bool qemu_write_pidfile(const char *path, Error **errp)
116 {
117 int fd;
118 char pidstr[32];
119
120 while (1) {
121 struct stat a, b;
122 struct flock lock = {
123 .l_type = F_WRLCK,
124 .l_whence = SEEK_SET,
125 .l_len = 0,
126 };
127
128 fd = qemu_open_old(path, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR);
129 if (fd == -1) {
130 error_setg_errno(errp, errno, "Cannot open pid file");
131 return false;
132 }
133
134 if (fstat(fd, &b) < 0) {
135 error_setg_errno(errp, errno, "Cannot stat file");
136 goto fail_close;
137 }
138
139 if (fcntl(fd, F_SETLK, &lock)) {
140 error_setg_errno(errp, errno, "Cannot lock pid file");
141 goto fail_close;
142 }
143
144 /*
145 * Now make sure the path we locked is the same one that now
146 * exists on the filesystem.
147 */
148 if (stat(path, &a) < 0) {
149 /*
150 * PID file disappeared, someone else must be racing with
151 * us, so try again.
152 */
153 close(fd);
154 continue;
155 }
156
157 if (a.st_ino == b.st_ino) {
158 break;
159 }
160
161 /*
162 * PID file was recreated, someone else must be racing with
163 * us, so try again.
164 */
165 close(fd);
166 }
167
168 if (ftruncate(fd, 0) < 0) {
169 error_setg_errno(errp, errno, "Failed to truncate pid file");
170 goto fail_unlink;
171 }
172
173 snprintf(pidstr, sizeof(pidstr), FMT_pid "\n", getpid());
174 if (write(fd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
175 error_setg(errp, "Failed to write pid file");
176 goto fail_unlink;
177 }
178
179 return true;
180
181 fail_unlink:
182 unlink(path);
183 fail_close:
184 close(fd);
185 return false;
186 }
187
188 void *qemu_oom_check(void *ptr)
189 {
190 if (ptr == NULL) {
191 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
192 abort();
193 }
194 return ptr;
195 }
196
197 void *qemu_try_memalign(size_t alignment, size_t size)
198 {
199 void *ptr;
200
201 if (alignment < sizeof(void*)) {
202 alignment = sizeof(void*);
203 }
204
205 #if defined(CONFIG_POSIX_MEMALIGN)
206 int ret;
207 ret = posix_memalign(&ptr, alignment, size);
208 if (ret != 0) {
209 errno = ret;
210 ptr = NULL;
211 }
212 #elif defined(CONFIG_BSD)
213 ptr = valloc(size);
214 #else
215 ptr = memalign(alignment, size);
216 #endif
217 trace_qemu_memalign(alignment, size, ptr);
218 return ptr;
219 }
220
221 void *qemu_memalign(size_t alignment, size_t size)
222 {
223 return qemu_oom_check(qemu_try_memalign(alignment, size));
224 }
225
226 /* alloc shared memory pages */
227 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
228 {
229 size_t align = QEMU_VMALLOC_ALIGN;
230 void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
231
232 if (ptr == MAP_FAILED) {
233 return NULL;
234 }
235
236 if (alignment) {
237 *alignment = align;
238 }
239
240 trace_qemu_anon_ram_alloc(size, ptr);
241 return ptr;
242 }
243
244 void qemu_vfree(void *ptr)
245 {
246 trace_qemu_vfree(ptr);
247 free(ptr);
248 }
249
250 void qemu_anon_ram_free(void *ptr, size_t size)
251 {
252 trace_qemu_anon_ram_free(ptr, size);
253 qemu_ram_munmap(-1, ptr, size);
254 }
255
256 void qemu_set_block(int fd)
257 {
258 int f;
259 f = fcntl(fd, F_GETFL);
260 assert(f != -1);
261 f = fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
262 assert(f != -1);
263 }
264
265 int qemu_try_set_nonblock(int fd)
266 {
267 int f;
268 f = fcntl(fd, F_GETFL);
269 if (f == -1) {
270 return -errno;
271 }
272 if (fcntl(fd, F_SETFL, f | O_NONBLOCK) == -1) {
273 #ifdef __OpenBSD__
274 /*
275 * Previous to OpenBSD 6.3, fcntl(F_SETFL) is not permitted on
276 * memory devices and sets errno to ENODEV.
277 * It's OK if we fail to set O_NONBLOCK on devices like /dev/null,
278 * because they will never block anyway.
279 */
280 if (errno == ENODEV) {
281 return 0;
282 }
283 #endif
284 return -errno;
285 }
286 return 0;
287 }
288
289 void qemu_set_nonblock(int fd)
290 {
291 int f;
292 f = qemu_try_set_nonblock(fd);
293 assert(f == 0);
294 }
295
296 int socket_set_fast_reuse(int fd)
297 {
298 int val = 1, ret;
299
300 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
301 (const char *)&val, sizeof(val));
302
303 assert(ret == 0);
304
305 return ret;
306 }
307
308 void qemu_set_cloexec(int fd)
309 {
310 int f;
311 f = fcntl(fd, F_GETFD);
312 assert(f != -1);
313 f = fcntl(fd, F_SETFD, f | FD_CLOEXEC);
314 assert(f != -1);
315 }
316
317 /*
318 * Creates a pipe with FD_CLOEXEC set on both file descriptors
319 */
320 int qemu_pipe(int pipefd[2])
321 {
322 int ret;
323
324 #ifdef CONFIG_PIPE2
325 ret = pipe2(pipefd, O_CLOEXEC);
326 if (ret != -1 || errno != ENOSYS) {
327 return ret;
328 }
329 #endif
330 ret = pipe(pipefd);
331 if (ret == 0) {
332 qemu_set_cloexec(pipefd[0]);
333 qemu_set_cloexec(pipefd[1]);
334 }
335
336 return ret;
337 }
338
339 char *
340 qemu_get_local_state_pathname(const char *relative_pathname)
341 {
342 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
343 relative_pathname);
344 }
345
346 void qemu_set_tty_echo(int fd, bool echo)
347 {
348 struct termios tty;
349
350 tcgetattr(fd, &tty);
351
352 if (echo) {
353 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
354 } else {
355 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
356 }
357
358 tcsetattr(fd, TCSANOW, &tty);
359 }
360
361 static const char *exec_dir;
362
363 void qemu_init_exec_dir(const char *argv0)
364 {
365 char *p = NULL;
366 char buf[PATH_MAX];
367
368 if (exec_dir) {
369 return;
370 }
371
372 #if defined(__linux__)
373 {
374 int len;
375 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
376 if (len > 0) {
377 buf[len] = 0;
378 p = buf;
379 }
380 }
381 #elif defined(__FreeBSD__) \
382 || (defined(__NetBSD__) && defined(KERN_PROC_PATHNAME))
383 {
384 #if defined(__FreeBSD__)
385 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
386 #else
387 static int mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
388 #endif
389 size_t len = sizeof(buf) - 1;
390
391 *buf = '\0';
392 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
393 *buf) {
394 buf[sizeof(buf) - 1] = '\0';
395 p = buf;
396 }
397 }
398 #elif defined(__APPLE__)
399 {
400 char fpath[PATH_MAX];
401 uint32_t len = sizeof(fpath);
402 if (_NSGetExecutablePath(fpath, &len) == 0) {
403 p = realpath(fpath, buf);
404 if (!p) {
405 return;
406 }
407 }
408 }
409 #elif defined(__HAIKU__)
410 {
411 image_info ii;
412 int32_t c = 0;
413
414 *buf = '\0';
415 while (get_next_image_info(0, &c, &ii) == B_OK) {
416 if (ii.type == B_APP_IMAGE) {
417 strncpy(buf, ii.name, sizeof(buf));
418 buf[sizeof(buf) - 1] = 0;
419 p = buf;
420 break;
421 }
422 }
423 }
424 #endif
425 /* If we don't have any way of figuring out the actual executable
426 location then try argv[0]. */
427 if (!p && argv0) {
428 p = realpath(argv0, buf);
429 }
430 if (p) {
431 exec_dir = g_path_get_dirname(p);
432 } else {
433 exec_dir = CONFIG_BINDIR;
434 }
435 }
436
437 const char *qemu_get_exec_dir(void)
438 {
439 return exec_dir;
440 }
441
442 static void sigbus_handler(int signal)
443 {
444 int i;
445 if (memset_thread) {
446 for (i = 0; i < memset_num_threads; i++) {
447 if (qemu_thread_is_self(&memset_thread[i].pgthread)) {
448 siglongjmp(memset_thread[i].env, 1);
449 }
450 }
451 }
452 }
453
454 static void *do_touch_pages(void *arg)
455 {
456 MemsetThread *memset_args = (MemsetThread *)arg;
457 sigset_t set, oldset;
458
459 /*
460 * On Linux, the page faults from the loop below can cause mmap_sem
461 * contention with allocation of the thread stacks. Do not start
462 * clearing until all threads have been created.
463 */
464 qemu_mutex_lock(&page_mutex);
465 while(!threads_created_flag){
466 qemu_cond_wait(&page_cond, &page_mutex);
467 }
468 qemu_mutex_unlock(&page_mutex);
469
470 /* unblock SIGBUS */
471 sigemptyset(&set);
472 sigaddset(&set, SIGBUS);
473 pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
474
475 if (sigsetjmp(memset_args->env, 1)) {
476 memset_thread_failed = true;
477 } else {
478 char *addr = memset_args->addr;
479 size_t numpages = memset_args->numpages;
480 size_t hpagesize = memset_args->hpagesize;
481 size_t i;
482 for (i = 0; i < numpages; i++) {
483 /*
484 * Read & write back the same value, so we don't
485 * corrupt existing user/app data that might be
486 * stored.
487 *
488 * 'volatile' to stop compiler optimizing this away
489 * to a no-op
490 *
491 * TODO: get a better solution from kernel so we
492 * don't need to write at all so we don't cause
493 * wear on the storage backing the region...
494 */
495 *(volatile char *)addr = *addr;
496 addr += hpagesize;
497 }
498 }
499 pthread_sigmask(SIG_SETMASK, &oldset, NULL);
500 return NULL;
501 }
502
503 static inline int get_memset_num_threads(int smp_cpus)
504 {
505 long host_procs = sysconf(_SC_NPROCESSORS_ONLN);
506 int ret = 1;
507
508 if (host_procs > 0) {
509 ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus);
510 }
511 /* In case sysconf() fails, we fall back to single threaded */
512 return ret;
513 }
514
515 static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
516 int smp_cpus)
517 {
518 static gsize initialized = 0;
519 size_t numpages_per_thread, leftover;
520 char *addr = area;
521 int i = 0;
522
523 if (g_once_init_enter(&initialized)) {
524 qemu_mutex_init(&page_mutex);
525 qemu_cond_init(&page_cond);
526 g_once_init_leave(&initialized, 1);
527 }
528
529 memset_thread_failed = false;
530 threads_created_flag = false;
531 memset_num_threads = get_memset_num_threads(smp_cpus);
532 memset_thread = g_new0(MemsetThread, memset_num_threads);
533 numpages_per_thread = numpages / memset_num_threads;
534 leftover = numpages % memset_num_threads;
535 for (i = 0; i < memset_num_threads; i++) {
536 memset_thread[i].addr = addr;
537 memset_thread[i].numpages = numpages_per_thread + (i < leftover);
538 memset_thread[i].hpagesize = hpagesize;
539 qemu_thread_create(&memset_thread[i].pgthread, "touch_pages",
540 do_touch_pages, &memset_thread[i],
541 QEMU_THREAD_JOINABLE);
542 addr += memset_thread[i].numpages * hpagesize;
543 }
544
545 qemu_mutex_lock(&page_mutex);
546 threads_created_flag = true;
547 qemu_cond_broadcast(&page_cond);
548 qemu_mutex_unlock(&page_mutex);
549
550 for (i = 0; i < memset_num_threads; i++) {
551 qemu_thread_join(&memset_thread[i].pgthread);
552 }
553 g_free(memset_thread);
554 memset_thread = NULL;
555
556 return memset_thread_failed;
557 }
558
559 void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
560 Error **errp)
561 {
562 int ret;
563 struct sigaction act, oldact;
564 size_t hpagesize = qemu_fd_getpagesize(fd);
565 size_t numpages = DIV_ROUND_UP(memory, hpagesize);
566
567 memset(&act, 0, sizeof(act));
568 act.sa_handler = &sigbus_handler;
569 act.sa_flags = 0;
570
571 ret = sigaction(SIGBUS, &act, &oldact);
572 if (ret) {
573 error_setg_errno(errp, errno,
574 "os_mem_prealloc: failed to install signal handler");
575 return;
576 }
577
578 /* touch pages simultaneously */
579 if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
580 error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
581 "pages available to allocate guest RAM");
582 }
583
584 ret = sigaction(SIGBUS, &oldact, NULL);
585 if (ret) {
586 /* Terminate QEMU since it can't recover from error */
587 perror("os_mem_prealloc: failed to reinstall signal handler");
588 exit(1);
589 }
590 }
591
592 char *qemu_get_pid_name(pid_t pid)
593 {
594 char *name = NULL;
595
596 #if defined(__FreeBSD__)
597 /* BSDs don't have /proc, but they provide a nice substitute */
598 struct kinfo_proc *proc = kinfo_getproc(pid);
599
600 if (proc) {
601 name = g_strdup(proc->ki_comm);
602 free(proc);
603 }
604 #else
605 /* Assume a system with reasonable procfs */
606 char *pid_path;
607 size_t len;
608
609 pid_path = g_strdup_printf("/proc/%d/cmdline", pid);
610 g_file_get_contents(pid_path, &name, &len, NULL);
611 g_free(pid_path);
612 #endif
613
614 return name;
615 }
616
617
618 pid_t qemu_fork(Error **errp)
619 {
620 sigset_t oldmask, newmask;
621 struct sigaction sig_action;
622 int saved_errno;
623 pid_t pid;
624
625 /*
626 * Need to block signals now, so that child process can safely
627 * kill off caller's signal handlers without a race.
628 */
629 sigfillset(&newmask);
630 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
631 error_setg_errno(errp, errno,
632 "cannot block signals");
633 return -1;
634 }
635
636 pid = fork();
637 saved_errno = errno;
638
639 if (pid < 0) {
640 /* attempt to restore signal mask, but ignore failure, to
641 * avoid obscuring the fork failure */
642 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
643 error_setg_errno(errp, saved_errno,
644 "cannot fork child process");
645 errno = saved_errno;
646 return -1;
647 } else if (pid) {
648 /* parent process */
649
650 /* Restore our original signal mask now that the child is
651 * safely running. Only documented failures are EFAULT (not
652 * possible, since we are using just-grabbed mask) or EINVAL
653 * (not possible, since we are using correct arguments). */
654 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
655 } else {
656 /* child process */
657 size_t i;
658
659 /* Clear out all signal handlers from parent so nothing
660 * unexpected can happen in our child once we unblock
661 * signals */
662 sig_action.sa_handler = SIG_DFL;
663 sig_action.sa_flags = 0;
664 sigemptyset(&sig_action.sa_mask);
665
666 for (i = 1; i < NSIG; i++) {
667 /* Only possible errors are EFAULT or EINVAL The former
668 * won't happen, the latter we expect, so no need to check
669 * return value */
670 (void)sigaction(i, &sig_action, NULL);
671 }
672
673 /* Unmask all signals in child, since we've no idea what the
674 * caller's done with their signal mask and don't want to
675 * propagate that to children */
676 sigemptyset(&newmask);
677 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
678 Error *local_err = NULL;
679 error_setg_errno(&local_err, errno,
680 "cannot unblock signals");
681 error_report_err(local_err);
682 _exit(1);
683 }
684 }
685 return pid;
686 }
687
688 void *qemu_alloc_stack(size_t *sz)
689 {
690 void *ptr, *guardpage;
691 int flags;
692 #ifdef CONFIG_DEBUG_STACK_USAGE
693 void *ptr2;
694 #endif
695 size_t pagesz = qemu_real_host_page_size;
696 #ifdef _SC_THREAD_STACK_MIN
697 /* avoid stacks smaller than _SC_THREAD_STACK_MIN */
698 long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN);
699 *sz = MAX(MAX(min_stack_sz, 0), *sz);
700 #endif
701 /* adjust stack size to a multiple of the page size */
702 *sz = ROUND_UP(*sz, pagesz);
703 /* allocate one extra page for the guard page */
704 *sz += pagesz;
705
706 flags = MAP_PRIVATE | MAP_ANONYMOUS;
707 #if defined(MAP_STACK) && defined(__OpenBSD__)
708 /* Only enable MAP_STACK on OpenBSD. Other OS's such as
709 * Linux/FreeBSD/NetBSD have a flag with the same name
710 * but have differing functionality. OpenBSD will SEGV
711 * if it spots execution with a stack pointer pointing
712 * at memory that was not allocated with MAP_STACK.
713 */
714 flags |= MAP_STACK;
715 #endif
716
717 ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, flags, -1, 0);
718 if (ptr == MAP_FAILED) {
719 perror("failed to allocate memory for stack");
720 abort();
721 }
722
723 #if defined(HOST_IA64)
724 /* separate register stack */
725 guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz);
726 #elif defined(HOST_HPPA)
727 /* stack grows up */
728 guardpage = ptr + *sz - pagesz;
729 #else
730 /* stack grows down */
731 guardpage = ptr;
732 #endif
733 if (mprotect(guardpage, pagesz, PROT_NONE) != 0) {
734 perror("failed to set up stack guard page");
735 abort();
736 }
737
738 #ifdef CONFIG_DEBUG_STACK_USAGE
739 for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
740 *(uint32_t *)ptr2 = 0xdeadbeaf;
741 }
742 #endif
743
744 return ptr;
745 }
746
747 #ifdef CONFIG_DEBUG_STACK_USAGE
748 static __thread unsigned int max_stack_usage;
749 #endif
750
751 void qemu_free_stack(void *stack, size_t sz)
752 {
753 #ifdef CONFIG_DEBUG_STACK_USAGE
754 unsigned int usage;
755 void *ptr;
756
757 for (ptr = stack + qemu_real_host_page_size; ptr < stack + sz;
758 ptr += sizeof(uint32_t)) {
759 if (*(uint32_t *)ptr != 0xdeadbeaf) {
760 break;
761 }
762 }
763 usage = sz - (uintptr_t) (ptr - stack);
764 if (usage > max_stack_usage) {
765 error_report("thread %d max stack usage increased from %u to %u",
766 qemu_get_thread_id(), max_stack_usage, usage);
767 max_stack_usage = usage;
768 }
769 #endif
770
771 munmap(stack, sz);
772 }
773
774 void sigaction_invoke(struct sigaction *action,
775 struct qemu_signalfd_siginfo *info)
776 {
777 siginfo_t si = {};
778 si.si_signo = info->ssi_signo;
779 si.si_errno = info->ssi_errno;
780 si.si_code = info->ssi_code;
781
782 /* Convert the minimal set of fields defined by POSIX.
783 * Positive si_code values are reserved for kernel-generated
784 * signals, where the valid siginfo fields are determined by
785 * the signal number. But according to POSIX, it is unspecified
786 * whether SI_USER and SI_QUEUE have values less than or equal to
787 * zero.
788 */
789 if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE ||
790 info->ssi_code <= 0) {
791 /* SIGTERM, etc. */
792 si.si_pid = info->ssi_pid;
793 si.si_uid = info->ssi_uid;
794 } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE ||
795 info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) {
796 si.si_addr = (void *)(uintptr_t)info->ssi_addr;
797 } else if (info->ssi_signo == SIGCHLD) {
798 si.si_pid = info->ssi_pid;
799 si.si_status = info->ssi_status;
800 si.si_uid = info->ssi_uid;
801 }
802 action->sa_sigaction(info->ssi_signo, &si, NULL);
803 }
804
805 #ifndef HOST_NAME_MAX
806 # ifdef _POSIX_HOST_NAME_MAX
807 # define HOST_NAME_MAX _POSIX_HOST_NAME_MAX
808 # else
809 # define HOST_NAME_MAX 255
810 # endif
811 #endif
812
813 char *qemu_get_host_name(Error **errp)
814 {
815 long len = -1;
816 g_autofree char *hostname = NULL;
817
818 #ifdef _SC_HOST_NAME_MAX
819 len = sysconf(_SC_HOST_NAME_MAX);
820 #endif /* _SC_HOST_NAME_MAX */
821
822 if (len < 0) {
823 len = HOST_NAME_MAX;
824 }
825
826 /* Unfortunately, gethostname() below does not guarantee a
827 * NULL terminated string. Therefore, allocate one byte more
828 * to be sure. */
829 hostname = g_new0(char, len + 1);
830
831 if (gethostname(hostname, len) < 0) {
832 error_setg_errno(errp, errno,
833 "cannot get hostname");
834 return NULL;
835 }
836
837 return g_steal_pointer(&hostname);
838 }
839
840 size_t qemu_get_host_physmem(void)
841 {
842 #ifdef _SC_PHYS_PAGES
843 long pages = sysconf(_SC_PHYS_PAGES);
844 if (pages > 0) {
845 if (pages > SIZE_MAX / qemu_real_host_page_size) {
846 return SIZE_MAX;
847 } else {
848 return pages * qemu_real_host_page_size;
849 }
850 }
851 #endif
852 return 0;
853 }