oslib: do not call g_strdup from qemu_get_exec_dir
[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 char exec_dir[PATH_MAX];
362
363 void qemu_init_exec_dir(const char *argv0)
364 {
365 char *dir;
366 char *p = NULL;
367 char buf[PATH_MAX];
368
369 if (exec_dir[0]) {
370 return;
371 }
372
373 #if defined(__linux__)
374 {
375 int len;
376 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
377 if (len > 0) {
378 buf[len] = 0;
379 p = buf;
380 }
381 }
382 #elif defined(__FreeBSD__) \
383 || (defined(__NetBSD__) && defined(KERN_PROC_PATHNAME))
384 {
385 #if defined(__FreeBSD__)
386 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
387 #else
388 static int mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
389 #endif
390 size_t len = sizeof(buf) - 1;
391
392 *buf = '\0';
393 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
394 *buf) {
395 buf[sizeof(buf) - 1] = '\0';
396 p = buf;
397 }
398 }
399 #elif defined(__APPLE__)
400 {
401 char fpath[PATH_MAX];
402 uint32_t len = sizeof(fpath);
403 if (_NSGetExecutablePath(fpath, &len) == 0) {
404 p = realpath(fpath, buf);
405 if (!p) {
406 return;
407 }
408 }
409 }
410 #elif defined(__HAIKU__)
411 {
412 image_info ii;
413 int32_t c = 0;
414
415 *buf = '\0';
416 while (get_next_image_info(0, &c, &ii) == B_OK) {
417 if (ii.type == B_APP_IMAGE) {
418 strncpy(buf, ii.name, sizeof(buf));
419 buf[sizeof(buf) - 1] = 0;
420 p = buf;
421 break;
422 }
423 }
424 }
425 #endif
426 /* If we don't have any way of figuring out the actual executable
427 location then try argv[0]. */
428 if (!p) {
429 if (!argv0) {
430 return;
431 }
432 p = realpath(argv0, buf);
433 if (!p) {
434 return;
435 }
436 }
437 dir = g_path_get_dirname(p);
438
439 pstrcpy(exec_dir, sizeof(exec_dir), dir);
440
441 g_free(dir);
442 }
443
444 const char *qemu_get_exec_dir(void)
445 {
446 return exec_dir;
447 }
448
449 static void sigbus_handler(int signal)
450 {
451 int i;
452 if (memset_thread) {
453 for (i = 0; i < memset_num_threads; i++) {
454 if (qemu_thread_is_self(&memset_thread[i].pgthread)) {
455 siglongjmp(memset_thread[i].env, 1);
456 }
457 }
458 }
459 }
460
461 static void *do_touch_pages(void *arg)
462 {
463 MemsetThread *memset_args = (MemsetThread *)arg;
464 sigset_t set, oldset;
465
466 /*
467 * On Linux, the page faults from the loop below can cause mmap_sem
468 * contention with allocation of the thread stacks. Do not start
469 * clearing until all threads have been created.
470 */
471 qemu_mutex_lock(&page_mutex);
472 while(!threads_created_flag){
473 qemu_cond_wait(&page_cond, &page_mutex);
474 }
475 qemu_mutex_unlock(&page_mutex);
476
477 /* unblock SIGBUS */
478 sigemptyset(&set);
479 sigaddset(&set, SIGBUS);
480 pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
481
482 if (sigsetjmp(memset_args->env, 1)) {
483 memset_thread_failed = true;
484 } else {
485 char *addr = memset_args->addr;
486 size_t numpages = memset_args->numpages;
487 size_t hpagesize = memset_args->hpagesize;
488 size_t i;
489 for (i = 0; i < numpages; i++) {
490 /*
491 * Read & write back the same value, so we don't
492 * corrupt existing user/app data that might be
493 * stored.
494 *
495 * 'volatile' to stop compiler optimizing this away
496 * to a no-op
497 *
498 * TODO: get a better solution from kernel so we
499 * don't need to write at all so we don't cause
500 * wear on the storage backing the region...
501 */
502 *(volatile char *)addr = *addr;
503 addr += hpagesize;
504 }
505 }
506 pthread_sigmask(SIG_SETMASK, &oldset, NULL);
507 return NULL;
508 }
509
510 static inline int get_memset_num_threads(int smp_cpus)
511 {
512 long host_procs = sysconf(_SC_NPROCESSORS_ONLN);
513 int ret = 1;
514
515 if (host_procs > 0) {
516 ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus);
517 }
518 /* In case sysconf() fails, we fall back to single threaded */
519 return ret;
520 }
521
522 static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
523 int smp_cpus)
524 {
525 static gsize initialized = 0;
526 size_t numpages_per_thread, leftover;
527 char *addr = area;
528 int i = 0;
529
530 if (g_once_init_enter(&initialized)) {
531 qemu_mutex_init(&page_mutex);
532 qemu_cond_init(&page_cond);
533 g_once_init_leave(&initialized, 1);
534 }
535
536 memset_thread_failed = false;
537 threads_created_flag = false;
538 memset_num_threads = get_memset_num_threads(smp_cpus);
539 memset_thread = g_new0(MemsetThread, memset_num_threads);
540 numpages_per_thread = numpages / memset_num_threads;
541 leftover = numpages % memset_num_threads;
542 for (i = 0; i < memset_num_threads; i++) {
543 memset_thread[i].addr = addr;
544 memset_thread[i].numpages = numpages_per_thread + (i < leftover);
545 memset_thread[i].hpagesize = hpagesize;
546 qemu_thread_create(&memset_thread[i].pgthread, "touch_pages",
547 do_touch_pages, &memset_thread[i],
548 QEMU_THREAD_JOINABLE);
549 addr += memset_thread[i].numpages * hpagesize;
550 }
551
552 qemu_mutex_lock(&page_mutex);
553 threads_created_flag = true;
554 qemu_cond_broadcast(&page_cond);
555 qemu_mutex_unlock(&page_mutex);
556
557 for (i = 0; i < memset_num_threads; i++) {
558 qemu_thread_join(&memset_thread[i].pgthread);
559 }
560 g_free(memset_thread);
561 memset_thread = NULL;
562
563 return memset_thread_failed;
564 }
565
566 void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
567 Error **errp)
568 {
569 int ret;
570 struct sigaction act, oldact;
571 size_t hpagesize = qemu_fd_getpagesize(fd);
572 size_t numpages = DIV_ROUND_UP(memory, hpagesize);
573
574 memset(&act, 0, sizeof(act));
575 act.sa_handler = &sigbus_handler;
576 act.sa_flags = 0;
577
578 ret = sigaction(SIGBUS, &act, &oldact);
579 if (ret) {
580 error_setg_errno(errp, errno,
581 "os_mem_prealloc: failed to install signal handler");
582 return;
583 }
584
585 /* touch pages simultaneously */
586 if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
587 error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
588 "pages available to allocate guest RAM");
589 }
590
591 ret = sigaction(SIGBUS, &oldact, NULL);
592 if (ret) {
593 /* Terminate QEMU since it can't recover from error */
594 perror("os_mem_prealloc: failed to reinstall signal handler");
595 exit(1);
596 }
597 }
598
599 char *qemu_get_pid_name(pid_t pid)
600 {
601 char *name = NULL;
602
603 #if defined(__FreeBSD__)
604 /* BSDs don't have /proc, but they provide a nice substitute */
605 struct kinfo_proc *proc = kinfo_getproc(pid);
606
607 if (proc) {
608 name = g_strdup(proc->ki_comm);
609 free(proc);
610 }
611 #else
612 /* Assume a system with reasonable procfs */
613 char *pid_path;
614 size_t len;
615
616 pid_path = g_strdup_printf("/proc/%d/cmdline", pid);
617 g_file_get_contents(pid_path, &name, &len, NULL);
618 g_free(pid_path);
619 #endif
620
621 return name;
622 }
623
624
625 pid_t qemu_fork(Error **errp)
626 {
627 sigset_t oldmask, newmask;
628 struct sigaction sig_action;
629 int saved_errno;
630 pid_t pid;
631
632 /*
633 * Need to block signals now, so that child process can safely
634 * kill off caller's signal handlers without a race.
635 */
636 sigfillset(&newmask);
637 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
638 error_setg_errno(errp, errno,
639 "cannot block signals");
640 return -1;
641 }
642
643 pid = fork();
644 saved_errno = errno;
645
646 if (pid < 0) {
647 /* attempt to restore signal mask, but ignore failure, to
648 * avoid obscuring the fork failure */
649 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
650 error_setg_errno(errp, saved_errno,
651 "cannot fork child process");
652 errno = saved_errno;
653 return -1;
654 } else if (pid) {
655 /* parent process */
656
657 /* Restore our original signal mask now that the child is
658 * safely running. Only documented failures are EFAULT (not
659 * possible, since we are using just-grabbed mask) or EINVAL
660 * (not possible, since we are using correct arguments). */
661 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
662 } else {
663 /* child process */
664 size_t i;
665
666 /* Clear out all signal handlers from parent so nothing
667 * unexpected can happen in our child once we unblock
668 * signals */
669 sig_action.sa_handler = SIG_DFL;
670 sig_action.sa_flags = 0;
671 sigemptyset(&sig_action.sa_mask);
672
673 for (i = 1; i < NSIG; i++) {
674 /* Only possible errors are EFAULT or EINVAL The former
675 * won't happen, the latter we expect, so no need to check
676 * return value */
677 (void)sigaction(i, &sig_action, NULL);
678 }
679
680 /* Unmask all signals in child, since we've no idea what the
681 * caller's done with their signal mask and don't want to
682 * propagate that to children */
683 sigemptyset(&newmask);
684 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
685 Error *local_err = NULL;
686 error_setg_errno(&local_err, errno,
687 "cannot unblock signals");
688 error_report_err(local_err);
689 _exit(1);
690 }
691 }
692 return pid;
693 }
694
695 void *qemu_alloc_stack(size_t *sz)
696 {
697 void *ptr, *guardpage;
698 int flags;
699 #ifdef CONFIG_DEBUG_STACK_USAGE
700 void *ptr2;
701 #endif
702 size_t pagesz = qemu_real_host_page_size;
703 #ifdef _SC_THREAD_STACK_MIN
704 /* avoid stacks smaller than _SC_THREAD_STACK_MIN */
705 long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN);
706 *sz = MAX(MAX(min_stack_sz, 0), *sz);
707 #endif
708 /* adjust stack size to a multiple of the page size */
709 *sz = ROUND_UP(*sz, pagesz);
710 /* allocate one extra page for the guard page */
711 *sz += pagesz;
712
713 flags = MAP_PRIVATE | MAP_ANONYMOUS;
714 #if defined(MAP_STACK) && defined(__OpenBSD__)
715 /* Only enable MAP_STACK on OpenBSD. Other OS's such as
716 * Linux/FreeBSD/NetBSD have a flag with the same name
717 * but have differing functionality. OpenBSD will SEGV
718 * if it spots execution with a stack pointer pointing
719 * at memory that was not allocated with MAP_STACK.
720 */
721 flags |= MAP_STACK;
722 #endif
723
724 ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, flags, -1, 0);
725 if (ptr == MAP_FAILED) {
726 perror("failed to allocate memory for stack");
727 abort();
728 }
729
730 #if defined(HOST_IA64)
731 /* separate register stack */
732 guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz);
733 #elif defined(HOST_HPPA)
734 /* stack grows up */
735 guardpage = ptr + *sz - pagesz;
736 #else
737 /* stack grows down */
738 guardpage = ptr;
739 #endif
740 if (mprotect(guardpage, pagesz, PROT_NONE) != 0) {
741 perror("failed to set up stack guard page");
742 abort();
743 }
744
745 #ifdef CONFIG_DEBUG_STACK_USAGE
746 for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
747 *(uint32_t *)ptr2 = 0xdeadbeaf;
748 }
749 #endif
750
751 return ptr;
752 }
753
754 #ifdef CONFIG_DEBUG_STACK_USAGE
755 static __thread unsigned int max_stack_usage;
756 #endif
757
758 void qemu_free_stack(void *stack, size_t sz)
759 {
760 #ifdef CONFIG_DEBUG_STACK_USAGE
761 unsigned int usage;
762 void *ptr;
763
764 for (ptr = stack + qemu_real_host_page_size; ptr < stack + sz;
765 ptr += sizeof(uint32_t)) {
766 if (*(uint32_t *)ptr != 0xdeadbeaf) {
767 break;
768 }
769 }
770 usage = sz - (uintptr_t) (ptr - stack);
771 if (usage > max_stack_usage) {
772 error_report("thread %d max stack usage increased from %u to %u",
773 qemu_get_thread_id(), max_stack_usage, usage);
774 max_stack_usage = usage;
775 }
776 #endif
777
778 munmap(stack, sz);
779 }
780
781 void sigaction_invoke(struct sigaction *action,
782 struct qemu_signalfd_siginfo *info)
783 {
784 siginfo_t si = {};
785 si.si_signo = info->ssi_signo;
786 si.si_errno = info->ssi_errno;
787 si.si_code = info->ssi_code;
788
789 /* Convert the minimal set of fields defined by POSIX.
790 * Positive si_code values are reserved for kernel-generated
791 * signals, where the valid siginfo fields are determined by
792 * the signal number. But according to POSIX, it is unspecified
793 * whether SI_USER and SI_QUEUE have values less than or equal to
794 * zero.
795 */
796 if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE ||
797 info->ssi_code <= 0) {
798 /* SIGTERM, etc. */
799 si.si_pid = info->ssi_pid;
800 si.si_uid = info->ssi_uid;
801 } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE ||
802 info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) {
803 si.si_addr = (void *)(uintptr_t)info->ssi_addr;
804 } else if (info->ssi_signo == SIGCHLD) {
805 si.si_pid = info->ssi_pid;
806 si.si_status = info->ssi_status;
807 si.si_uid = info->ssi_uid;
808 }
809 action->sa_sigaction(info->ssi_signo, &si, NULL);
810 }
811
812 #ifndef HOST_NAME_MAX
813 # ifdef _POSIX_HOST_NAME_MAX
814 # define HOST_NAME_MAX _POSIX_HOST_NAME_MAX
815 # else
816 # define HOST_NAME_MAX 255
817 # endif
818 #endif
819
820 char *qemu_get_host_name(Error **errp)
821 {
822 long len = -1;
823 g_autofree char *hostname = NULL;
824
825 #ifdef _SC_HOST_NAME_MAX
826 len = sysconf(_SC_HOST_NAME_MAX);
827 #endif /* _SC_HOST_NAME_MAX */
828
829 if (len < 0) {
830 len = HOST_NAME_MAX;
831 }
832
833 /* Unfortunately, gethostname() below does not guarantee a
834 * NULL terminated string. Therefore, allocate one byte more
835 * to be sure. */
836 hostname = g_new0(char, len + 1);
837
838 if (gethostname(hostname, len) < 0) {
839 error_setg_errno(errp, errno,
840 "cannot get hostname");
841 return NULL;
842 }
843
844 return g_steal_pointer(&hostname);
845 }
846
847 size_t qemu_get_host_physmem(void)
848 {
849 #ifdef _SC_PHYS_PAGES
850 long pages = sysconf(_SC_PHYS_PAGES);
851 if (pages > 0) {
852 if (pages > SIZE_MAX / qemu_real_host_page_size) {
853 return SIZE_MAX;
854 } else {
855 return pages * qemu_real_host_page_size;
856 }
857 }
858 #endif
859 return 0;
860 }