oslib-posix: relocate path to /var
[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 g_autofree char *dir = g_strdup_printf("%s/%s",
343 CONFIG_QEMU_LOCALSTATEDIR,
344 relative_pathname);
345 return get_relocated_path(dir);
346 }
347
348 void qemu_set_tty_echo(int fd, bool echo)
349 {
350 struct termios tty;
351
352 tcgetattr(fd, &tty);
353
354 if (echo) {
355 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
356 } else {
357 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
358 }
359
360 tcsetattr(fd, TCSANOW, &tty);
361 }
362
363 static const char *exec_dir;
364
365 void qemu_init_exec_dir(const char *argv0)
366 {
367 char *p = NULL;
368 char buf[PATH_MAX];
369
370 if (exec_dir) {
371 return;
372 }
373
374 #if defined(__linux__)
375 {
376 int len;
377 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
378 if (len > 0) {
379 buf[len] = 0;
380 p = buf;
381 }
382 }
383 #elif defined(__FreeBSD__) \
384 || (defined(__NetBSD__) && defined(KERN_PROC_PATHNAME))
385 {
386 #if defined(__FreeBSD__)
387 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
388 #else
389 static int mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
390 #endif
391 size_t len = sizeof(buf) - 1;
392
393 *buf = '\0';
394 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
395 *buf) {
396 buf[sizeof(buf) - 1] = '\0';
397 p = buf;
398 }
399 }
400 #elif defined(__APPLE__)
401 {
402 char fpath[PATH_MAX];
403 uint32_t len = sizeof(fpath);
404 if (_NSGetExecutablePath(fpath, &len) == 0) {
405 p = realpath(fpath, buf);
406 if (!p) {
407 return;
408 }
409 }
410 }
411 #elif defined(__HAIKU__)
412 {
413 image_info ii;
414 int32_t c = 0;
415
416 *buf = '\0';
417 while (get_next_image_info(0, &c, &ii) == B_OK) {
418 if (ii.type == B_APP_IMAGE) {
419 strncpy(buf, ii.name, sizeof(buf));
420 buf[sizeof(buf) - 1] = 0;
421 p = buf;
422 break;
423 }
424 }
425 }
426 #endif
427 /* If we don't have any way of figuring out the actual executable
428 location then try argv[0]. */
429 if (!p && argv0) {
430 p = realpath(argv0, buf);
431 }
432 if (p) {
433 exec_dir = g_path_get_dirname(p);
434 } else {
435 exec_dir = CONFIG_BINDIR;
436 }
437 }
438
439 const char *qemu_get_exec_dir(void)
440 {
441 return exec_dir;
442 }
443
444 static void sigbus_handler(int signal)
445 {
446 int i;
447 if (memset_thread) {
448 for (i = 0; i < memset_num_threads; i++) {
449 if (qemu_thread_is_self(&memset_thread[i].pgthread)) {
450 siglongjmp(memset_thread[i].env, 1);
451 }
452 }
453 }
454 }
455
456 static void *do_touch_pages(void *arg)
457 {
458 MemsetThread *memset_args = (MemsetThread *)arg;
459 sigset_t set, oldset;
460
461 /*
462 * On Linux, the page faults from the loop below can cause mmap_sem
463 * contention with allocation of the thread stacks. Do not start
464 * clearing until all threads have been created.
465 */
466 qemu_mutex_lock(&page_mutex);
467 while(!threads_created_flag){
468 qemu_cond_wait(&page_cond, &page_mutex);
469 }
470 qemu_mutex_unlock(&page_mutex);
471
472 /* unblock SIGBUS */
473 sigemptyset(&set);
474 sigaddset(&set, SIGBUS);
475 pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
476
477 if (sigsetjmp(memset_args->env, 1)) {
478 memset_thread_failed = true;
479 } else {
480 char *addr = memset_args->addr;
481 size_t numpages = memset_args->numpages;
482 size_t hpagesize = memset_args->hpagesize;
483 size_t i;
484 for (i = 0; i < numpages; i++) {
485 /*
486 * Read & write back the same value, so we don't
487 * corrupt existing user/app data that might be
488 * stored.
489 *
490 * 'volatile' to stop compiler optimizing this away
491 * to a no-op
492 *
493 * TODO: get a better solution from kernel so we
494 * don't need to write at all so we don't cause
495 * wear on the storage backing the region...
496 */
497 *(volatile char *)addr = *addr;
498 addr += hpagesize;
499 }
500 }
501 pthread_sigmask(SIG_SETMASK, &oldset, NULL);
502 return NULL;
503 }
504
505 static inline int get_memset_num_threads(int smp_cpus)
506 {
507 long host_procs = sysconf(_SC_NPROCESSORS_ONLN);
508 int ret = 1;
509
510 if (host_procs > 0) {
511 ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus);
512 }
513 /* In case sysconf() fails, we fall back to single threaded */
514 return ret;
515 }
516
517 static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
518 int smp_cpus)
519 {
520 static gsize initialized = 0;
521 size_t numpages_per_thread, leftover;
522 char *addr = area;
523 int i = 0;
524
525 if (g_once_init_enter(&initialized)) {
526 qemu_mutex_init(&page_mutex);
527 qemu_cond_init(&page_cond);
528 g_once_init_leave(&initialized, 1);
529 }
530
531 memset_thread_failed = false;
532 threads_created_flag = false;
533 memset_num_threads = get_memset_num_threads(smp_cpus);
534 memset_thread = g_new0(MemsetThread, memset_num_threads);
535 numpages_per_thread = numpages / memset_num_threads;
536 leftover = numpages % memset_num_threads;
537 for (i = 0; i < memset_num_threads; i++) {
538 memset_thread[i].addr = addr;
539 memset_thread[i].numpages = numpages_per_thread + (i < leftover);
540 memset_thread[i].hpagesize = hpagesize;
541 qemu_thread_create(&memset_thread[i].pgthread, "touch_pages",
542 do_touch_pages, &memset_thread[i],
543 QEMU_THREAD_JOINABLE);
544 addr += memset_thread[i].numpages * hpagesize;
545 }
546
547 qemu_mutex_lock(&page_mutex);
548 threads_created_flag = true;
549 qemu_cond_broadcast(&page_cond);
550 qemu_mutex_unlock(&page_mutex);
551
552 for (i = 0; i < memset_num_threads; i++) {
553 qemu_thread_join(&memset_thread[i].pgthread);
554 }
555 g_free(memset_thread);
556 memset_thread = NULL;
557
558 return memset_thread_failed;
559 }
560
561 void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
562 Error **errp)
563 {
564 int ret;
565 struct sigaction act, oldact;
566 size_t hpagesize = qemu_fd_getpagesize(fd);
567 size_t numpages = DIV_ROUND_UP(memory, hpagesize);
568
569 memset(&act, 0, sizeof(act));
570 act.sa_handler = &sigbus_handler;
571 act.sa_flags = 0;
572
573 ret = sigaction(SIGBUS, &act, &oldact);
574 if (ret) {
575 error_setg_errno(errp, errno,
576 "os_mem_prealloc: failed to install signal handler");
577 return;
578 }
579
580 /* touch pages simultaneously */
581 if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
582 error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
583 "pages available to allocate guest RAM");
584 }
585
586 ret = sigaction(SIGBUS, &oldact, NULL);
587 if (ret) {
588 /* Terminate QEMU since it can't recover from error */
589 perror("os_mem_prealloc: failed to reinstall signal handler");
590 exit(1);
591 }
592 }
593
594 char *qemu_get_pid_name(pid_t pid)
595 {
596 char *name = NULL;
597
598 #if defined(__FreeBSD__)
599 /* BSDs don't have /proc, but they provide a nice substitute */
600 struct kinfo_proc *proc = kinfo_getproc(pid);
601
602 if (proc) {
603 name = g_strdup(proc->ki_comm);
604 free(proc);
605 }
606 #else
607 /* Assume a system with reasonable procfs */
608 char *pid_path;
609 size_t len;
610
611 pid_path = g_strdup_printf("/proc/%d/cmdline", pid);
612 g_file_get_contents(pid_path, &name, &len, NULL);
613 g_free(pid_path);
614 #endif
615
616 return name;
617 }
618
619
620 pid_t qemu_fork(Error **errp)
621 {
622 sigset_t oldmask, newmask;
623 struct sigaction sig_action;
624 int saved_errno;
625 pid_t pid;
626
627 /*
628 * Need to block signals now, so that child process can safely
629 * kill off caller's signal handlers without a race.
630 */
631 sigfillset(&newmask);
632 if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
633 error_setg_errno(errp, errno,
634 "cannot block signals");
635 return -1;
636 }
637
638 pid = fork();
639 saved_errno = errno;
640
641 if (pid < 0) {
642 /* attempt to restore signal mask, but ignore failure, to
643 * avoid obscuring the fork failure */
644 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
645 error_setg_errno(errp, saved_errno,
646 "cannot fork child process");
647 errno = saved_errno;
648 return -1;
649 } else if (pid) {
650 /* parent process */
651
652 /* Restore our original signal mask now that the child is
653 * safely running. Only documented failures are EFAULT (not
654 * possible, since we are using just-grabbed mask) or EINVAL
655 * (not possible, since we are using correct arguments). */
656 (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
657 } else {
658 /* child process */
659 size_t i;
660
661 /* Clear out all signal handlers from parent so nothing
662 * unexpected can happen in our child once we unblock
663 * signals */
664 sig_action.sa_handler = SIG_DFL;
665 sig_action.sa_flags = 0;
666 sigemptyset(&sig_action.sa_mask);
667
668 for (i = 1; i < NSIG; i++) {
669 /* Only possible errors are EFAULT or EINVAL The former
670 * won't happen, the latter we expect, so no need to check
671 * return value */
672 (void)sigaction(i, &sig_action, NULL);
673 }
674
675 /* Unmask all signals in child, since we've no idea what the
676 * caller's done with their signal mask and don't want to
677 * propagate that to children */
678 sigemptyset(&newmask);
679 if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
680 Error *local_err = NULL;
681 error_setg_errno(&local_err, errno,
682 "cannot unblock signals");
683 error_report_err(local_err);
684 _exit(1);
685 }
686 }
687 return pid;
688 }
689
690 void *qemu_alloc_stack(size_t *sz)
691 {
692 void *ptr, *guardpage;
693 int flags;
694 #ifdef CONFIG_DEBUG_STACK_USAGE
695 void *ptr2;
696 #endif
697 size_t pagesz = qemu_real_host_page_size;
698 #ifdef _SC_THREAD_STACK_MIN
699 /* avoid stacks smaller than _SC_THREAD_STACK_MIN */
700 long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN);
701 *sz = MAX(MAX(min_stack_sz, 0), *sz);
702 #endif
703 /* adjust stack size to a multiple of the page size */
704 *sz = ROUND_UP(*sz, pagesz);
705 /* allocate one extra page for the guard page */
706 *sz += pagesz;
707
708 flags = MAP_PRIVATE | MAP_ANONYMOUS;
709 #if defined(MAP_STACK) && defined(__OpenBSD__)
710 /* Only enable MAP_STACK on OpenBSD. Other OS's such as
711 * Linux/FreeBSD/NetBSD have a flag with the same name
712 * but have differing functionality. OpenBSD will SEGV
713 * if it spots execution with a stack pointer pointing
714 * at memory that was not allocated with MAP_STACK.
715 */
716 flags |= MAP_STACK;
717 #endif
718
719 ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, flags, -1, 0);
720 if (ptr == MAP_FAILED) {
721 perror("failed to allocate memory for stack");
722 abort();
723 }
724
725 #if defined(HOST_IA64)
726 /* separate register stack */
727 guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz);
728 #elif defined(HOST_HPPA)
729 /* stack grows up */
730 guardpage = ptr + *sz - pagesz;
731 #else
732 /* stack grows down */
733 guardpage = ptr;
734 #endif
735 if (mprotect(guardpage, pagesz, PROT_NONE) != 0) {
736 perror("failed to set up stack guard page");
737 abort();
738 }
739
740 #ifdef CONFIG_DEBUG_STACK_USAGE
741 for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
742 *(uint32_t *)ptr2 = 0xdeadbeaf;
743 }
744 #endif
745
746 return ptr;
747 }
748
749 #ifdef CONFIG_DEBUG_STACK_USAGE
750 static __thread unsigned int max_stack_usage;
751 #endif
752
753 void qemu_free_stack(void *stack, size_t sz)
754 {
755 #ifdef CONFIG_DEBUG_STACK_USAGE
756 unsigned int usage;
757 void *ptr;
758
759 for (ptr = stack + qemu_real_host_page_size; ptr < stack + sz;
760 ptr += sizeof(uint32_t)) {
761 if (*(uint32_t *)ptr != 0xdeadbeaf) {
762 break;
763 }
764 }
765 usage = sz - (uintptr_t) (ptr - stack);
766 if (usage > max_stack_usage) {
767 error_report("thread %d max stack usage increased from %u to %u",
768 qemu_get_thread_id(), max_stack_usage, usage);
769 max_stack_usage = usage;
770 }
771 #endif
772
773 munmap(stack, sz);
774 }
775
776 void sigaction_invoke(struct sigaction *action,
777 struct qemu_signalfd_siginfo *info)
778 {
779 siginfo_t si = {};
780 si.si_signo = info->ssi_signo;
781 si.si_errno = info->ssi_errno;
782 si.si_code = info->ssi_code;
783
784 /* Convert the minimal set of fields defined by POSIX.
785 * Positive si_code values are reserved for kernel-generated
786 * signals, where the valid siginfo fields are determined by
787 * the signal number. But according to POSIX, it is unspecified
788 * whether SI_USER and SI_QUEUE have values less than or equal to
789 * zero.
790 */
791 if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE ||
792 info->ssi_code <= 0) {
793 /* SIGTERM, etc. */
794 si.si_pid = info->ssi_pid;
795 si.si_uid = info->ssi_uid;
796 } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE ||
797 info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) {
798 si.si_addr = (void *)(uintptr_t)info->ssi_addr;
799 } else if (info->ssi_signo == SIGCHLD) {
800 si.si_pid = info->ssi_pid;
801 si.si_status = info->ssi_status;
802 si.si_uid = info->ssi_uid;
803 }
804 action->sa_sigaction(info->ssi_signo, &si, NULL);
805 }
806
807 #ifndef HOST_NAME_MAX
808 # ifdef _POSIX_HOST_NAME_MAX
809 # define HOST_NAME_MAX _POSIX_HOST_NAME_MAX
810 # else
811 # define HOST_NAME_MAX 255
812 # endif
813 #endif
814
815 char *qemu_get_host_name(Error **errp)
816 {
817 long len = -1;
818 g_autofree char *hostname = NULL;
819
820 #ifdef _SC_HOST_NAME_MAX
821 len = sysconf(_SC_HOST_NAME_MAX);
822 #endif /* _SC_HOST_NAME_MAX */
823
824 if (len < 0) {
825 len = HOST_NAME_MAX;
826 }
827
828 /* Unfortunately, gethostname() below does not guarantee a
829 * NULL terminated string. Therefore, allocate one byte more
830 * to be sure. */
831 hostname = g_new0(char, len + 1);
832
833 if (gethostname(hostname, len) < 0) {
834 error_setg_errno(errp, errno,
835 "cannot get hostname");
836 return NULL;
837 }
838
839 return g_steal_pointer(&hostname);
840 }
841
842 size_t qemu_get_host_physmem(void)
843 {
844 #ifdef _SC_PHYS_PAGES
845 long pages = sysconf(_SC_PHYS_PAGES);
846 if (pages > 0) {
847 if (pages > SIZE_MAX / qemu_real_host_page_size) {
848 return SIZE_MAX;
849 } else {
850 return pages * qemu_real_host_page_size;
851 }
852 }
853 #endif
854 return 0;
855 }