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