xref: /openbmc/qemu/util/osdep.c (revision 448058aa99aaf30e7b8978508e575284a19fcfc9)
1 /*
2  * QEMU low level functions
3  *
4  * Copyright (c) 2003 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #include "qemu/osdep.h"
25 
26 /* Needed early for CONFIG_BSD etc. */
27 
28 #ifdef CONFIG_SOLARIS
29 #include <sys/statvfs.h>
30 /* See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for
31    discussion about Solaris header problems */
32 extern int madvise(char *, size_t, int);
33 #endif
34 
35 #include "qemu-common.h"
36 #include "qemu/cutils.h"
37 #include "qemu/sockets.h"
38 #include "qemu/error-report.h"
39 #include "monitor/monitor.h"
40 
41 static bool fips_enabled = false;
42 
43 static const char *hw_version = QEMU_HW_VERSION;
44 
45 int socket_set_cork(int fd, int v)
46 {
47 #if defined(SOL_TCP) && defined(TCP_CORK)
48     return qemu_setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v));
49 #else
50     return 0;
51 #endif
52 }
53 
54 int socket_set_nodelay(int fd)
55 {
56     int v = 1;
57     return qemu_setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v));
58 }
59 
60 int qemu_madvise(void *addr, size_t len, int advice)
61 {
62     if (advice == QEMU_MADV_INVALID) {
63         errno = EINVAL;
64         return -1;
65     }
66 #if defined(CONFIG_MADVISE)
67     return madvise(addr, len, advice);
68 #elif defined(CONFIG_POSIX_MADVISE)
69     return posix_madvise(addr, len, advice);
70 #else
71     errno = EINVAL;
72     return -1;
73 #endif
74 }
75 
76 static int qemu_mprotect__osdep(void *addr, size_t size, int prot)
77 {
78     g_assert(!((uintptr_t)addr & ~qemu_real_host_page_mask));
79     g_assert(!(size & ~qemu_real_host_page_mask));
80 
81 #ifdef _WIN32
82     DWORD old_protect;
83 
84     if (!VirtualProtect(addr, size, prot, &old_protect)) {
85         g_autofree gchar *emsg = g_win32_error_message(GetLastError());
86         error_report("%s: VirtualProtect failed: %s", __func__, emsg);
87         return -1;
88     }
89     return 0;
90 #else
91     if (mprotect(addr, size, prot)) {
92         error_report("%s: mprotect failed: %s", __func__, strerror(errno));
93         return -1;
94     }
95     return 0;
96 #endif
97 }
98 
99 int qemu_mprotect_rwx(void *addr, size_t size)
100 {
101 #ifdef _WIN32
102     return qemu_mprotect__osdep(addr, size, PAGE_EXECUTE_READWRITE);
103 #else
104     return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC);
105 #endif
106 }
107 
108 int qemu_mprotect_none(void *addr, size_t size)
109 {
110 #ifdef _WIN32
111     return qemu_mprotect__osdep(addr, size, PAGE_NOACCESS);
112 #else
113     return qemu_mprotect__osdep(addr, size, PROT_NONE);
114 #endif
115 }
116 
117 #ifndef _WIN32
118 
119 static int fcntl_op_setlk = -1;
120 static int fcntl_op_getlk = -1;
121 
122 /*
123  * Dups an fd and sets the flags
124  */
125 int qemu_dup_flags(int fd, int flags)
126 {
127     int ret;
128     int serrno;
129     int dup_flags;
130 
131     ret = qemu_dup(fd);
132     if (ret == -1) {
133         goto fail;
134     }
135 
136     dup_flags = fcntl(ret, F_GETFL);
137     if (dup_flags == -1) {
138         goto fail;
139     }
140 
141     if ((flags & O_SYNC) != (dup_flags & O_SYNC)) {
142         errno = EINVAL;
143         goto fail;
144     }
145 
146     /* Set/unset flags that we can with fcntl */
147     if (fcntl(ret, F_SETFL, flags) == -1) {
148         goto fail;
149     }
150 
151     /* Truncate the file in the cases that open() would truncate it */
152     if (flags & O_TRUNC ||
153             ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) {
154         if (ftruncate(ret, 0) == -1) {
155             goto fail;
156         }
157     }
158 
159     return ret;
160 
161 fail:
162     serrno = errno;
163     if (ret != -1) {
164         close(ret);
165     }
166     errno = serrno;
167     return -1;
168 }
169 
170 int qemu_dup(int fd)
171 {
172     int ret;
173 #ifdef F_DUPFD_CLOEXEC
174     ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
175 #else
176     ret = dup(fd);
177     if (ret != -1) {
178         qemu_set_cloexec(ret);
179     }
180 #endif
181     return ret;
182 }
183 
184 static int qemu_parse_fdset(const char *param)
185 {
186     return qemu_parse_fd(param);
187 }
188 
189 static void qemu_probe_lock_ops(void)
190 {
191     if (fcntl_op_setlk == -1) {
192 #ifdef F_OFD_SETLK
193         int fd;
194         int ret;
195         struct flock fl = {
196             .l_whence = SEEK_SET,
197             .l_start  = 0,
198             .l_len    = 0,
199             .l_type   = F_WRLCK,
200         };
201 
202         fd = open("/dev/null", O_RDWR);
203         if (fd < 0) {
204             fprintf(stderr,
205                     "Failed to open /dev/null for OFD lock probing: %s\n",
206                     strerror(errno));
207             fcntl_op_setlk = F_SETLK;
208             fcntl_op_getlk = F_GETLK;
209             return;
210         }
211         ret = fcntl(fd, F_OFD_GETLK, &fl);
212         close(fd);
213         if (!ret) {
214             fcntl_op_setlk = F_OFD_SETLK;
215             fcntl_op_getlk = F_OFD_GETLK;
216         } else {
217             fcntl_op_setlk = F_SETLK;
218             fcntl_op_getlk = F_GETLK;
219         }
220 #else
221         fcntl_op_setlk = F_SETLK;
222         fcntl_op_getlk = F_GETLK;
223 #endif
224     }
225 }
226 
227 bool qemu_has_ofd_lock(void)
228 {
229     qemu_probe_lock_ops();
230 #ifdef F_OFD_SETLK
231     return fcntl_op_setlk == F_OFD_SETLK;
232 #else
233     return false;
234 #endif
235 }
236 
237 static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
238 {
239     int ret;
240     struct flock fl = {
241         .l_whence = SEEK_SET,
242         .l_start  = start,
243         .l_len    = len,
244         .l_type   = fl_type,
245     };
246     qemu_probe_lock_ops();
247     do {
248         ret = fcntl(fd, fcntl_op_setlk, &fl);
249     } while (ret == -1 && errno == EINTR);
250     return ret == -1 ? -errno : 0;
251 }
252 
253 int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive)
254 {
255     return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK);
256 }
257 
258 int qemu_unlock_fd(int fd, int64_t start, int64_t len)
259 {
260     return qemu_lock_fcntl(fd, start, len, F_UNLCK);
261 }
262 
263 int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
264 {
265     int ret;
266     struct flock fl = {
267         .l_whence = SEEK_SET,
268         .l_start  = start,
269         .l_len    = len,
270         .l_type   = exclusive ? F_WRLCK : F_RDLCK,
271     };
272     qemu_probe_lock_ops();
273     ret = fcntl(fd, fcntl_op_getlk, &fl);
274     if (ret == -1) {
275         return -errno;
276     } else {
277         return fl.l_type == F_UNLCK ? 0 : -EAGAIN;
278     }
279 }
280 #endif
281 
282 static int qemu_open_cloexec(const char *name, int flags, mode_t mode)
283 {
284     int ret;
285 #ifdef O_CLOEXEC
286     ret = open(name, flags | O_CLOEXEC, mode);
287 #else
288     ret = open(name, flags, mode);
289     if (ret >= 0) {
290         qemu_set_cloexec(ret);
291     }
292 #endif
293     return ret;
294 }
295 
296 /*
297  * Opens a file with FD_CLOEXEC set
298  */
299 int qemu_open_old(const char *name, int flags, ...)
300 {
301     int ret;
302     int mode = 0;
303 
304 #ifndef _WIN32
305     const char *fdset_id_str;
306 
307     /* Attempt dup of fd from fd set */
308     if (strstart(name, "/dev/fdset/", &fdset_id_str)) {
309         int64_t fdset_id;
310         int dupfd;
311 
312         fdset_id = qemu_parse_fdset(fdset_id_str);
313         if (fdset_id == -1) {
314             errno = EINVAL;
315             return -1;
316         }
317 
318         dupfd = monitor_fdset_dup_fd_add(fdset_id, flags);
319         if (dupfd == -1) {
320             return -1;
321         }
322 
323         return dupfd;
324     }
325 #endif
326 
327     if (flags & O_CREAT) {
328         va_list ap;
329 
330         va_start(ap, flags);
331         mode = va_arg(ap, int);
332         va_end(ap);
333     }
334 
335     ret = qemu_open_cloexec(name, flags, mode);
336 
337 #ifdef O_DIRECT
338     if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
339         error_report("file system may not support O_DIRECT");
340         errno = EINVAL; /* in case it was clobbered */
341     }
342 #endif /* O_DIRECT */
343 
344     return ret;
345 }
346 
347 int qemu_close(int fd)
348 {
349     int64_t fdset_id;
350 
351     /* Close fd that was dup'd from an fdset */
352     fdset_id = monitor_fdset_dup_fd_find(fd);
353     if (fdset_id != -1) {
354         int ret;
355 
356         ret = close(fd);
357         if (ret == 0) {
358             monitor_fdset_dup_fd_remove(fd);
359         }
360 
361         return ret;
362     }
363 
364     return close(fd);
365 }
366 
367 /*
368  * Delete a file from the filesystem, unless the filename is /dev/fdset/...
369  *
370  * Returns: On success, zero is returned.  On error, -1 is returned,
371  * and errno is set appropriately.
372  */
373 int qemu_unlink(const char *name)
374 {
375     if (g_str_has_prefix(name, "/dev/fdset/")) {
376         return 0;
377     }
378 
379     return unlink(name);
380 }
381 
382 /*
383  * A variant of write(2) which handles partial write.
384  *
385  * Return the number of bytes transferred.
386  * Set errno if fewer than `count' bytes are written.
387  *
388  * This function don't work with non-blocking fd's.
389  * Any of the possibilities with non-bloking fd's is bad:
390  *   - return a short write (then name is wrong)
391  *   - busy wait adding (errno == EAGAIN) to the loop
392  */
393 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
394 {
395     ssize_t ret = 0;
396     ssize_t total = 0;
397 
398     while (count) {
399         ret = write(fd, buf, count);
400         if (ret < 0) {
401             if (errno == EINTR)
402                 continue;
403             break;
404         }
405 
406         count -= ret;
407         buf += ret;
408         total += ret;
409     }
410 
411     return total;
412 }
413 
414 /*
415  * Opens a socket with FD_CLOEXEC set
416  */
417 int qemu_socket(int domain, int type, int protocol)
418 {
419     int ret;
420 
421 #ifdef SOCK_CLOEXEC
422     ret = socket(domain, type | SOCK_CLOEXEC, protocol);
423     if (ret != -1 || errno != EINVAL) {
424         return ret;
425     }
426 #endif
427     ret = socket(domain, type, protocol);
428     if (ret >= 0) {
429         qemu_set_cloexec(ret);
430     }
431 
432     return ret;
433 }
434 
435 /*
436  * Accept a connection and set FD_CLOEXEC
437  */
438 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
439 {
440     int ret;
441 
442 #ifdef CONFIG_ACCEPT4
443     ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
444     if (ret != -1 || errno != ENOSYS) {
445         return ret;
446     }
447 #endif
448     ret = accept(s, addr, addrlen);
449     if (ret >= 0) {
450         qemu_set_cloexec(ret);
451     }
452 
453     return ret;
454 }
455 
456 void qemu_set_hw_version(const char *version)
457 {
458     hw_version = version;
459 }
460 
461 const char *qemu_hw_version(void)
462 {
463     return hw_version;
464 }
465 
466 void fips_set_state(bool requested)
467 {
468 #ifdef __linux__
469     if (requested) {
470         FILE *fds = fopen("/proc/sys/crypto/fips_enabled", "r");
471         if (fds != NULL) {
472             fips_enabled = (fgetc(fds) == '1');
473             fclose(fds);
474         }
475     }
476 #else
477     fips_enabled = false;
478 #endif /* __linux__ */
479 
480 #ifdef _FIPS_DEBUG
481     fprintf(stderr, "FIPS mode %s (requested %s)\n",
482             (fips_enabled ? "enabled" : "disabled"),
483             (requested ? "enabled" : "disabled"));
484 #endif
485 }
486 
487 bool fips_get_state(void)
488 {
489     return fips_enabled;
490 }
491 
492 #ifdef _WIN32
493 static void socket_cleanup(void)
494 {
495     WSACleanup();
496 }
497 #endif
498 
499 int socket_init(void)
500 {
501 #ifdef _WIN32
502     WSADATA Data;
503     int ret, err;
504 
505     ret = WSAStartup(MAKEWORD(2, 2), &Data);
506     if (ret != 0) {
507         err = WSAGetLastError();
508         fprintf(stderr, "WSAStartup: %d\n", err);
509         return -1;
510     }
511     atexit(socket_cleanup);
512 #endif
513     return 0;
514 }
515 
516 
517 #ifndef CONFIG_IOVEC
518 /* helper function for iov_send_recv() */
519 static ssize_t
520 readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write)
521 {
522     unsigned i = 0;
523     ssize_t ret = 0;
524     while (i < iov_cnt) {
525         ssize_t r = do_write
526             ? write(fd, iov[i].iov_base, iov[i].iov_len)
527             : read(fd, iov[i].iov_base, iov[i].iov_len);
528         if (r > 0) {
529             ret += r;
530         } else if (!r) {
531             break;
532         } else if (errno == EINTR) {
533             continue;
534         } else {
535             /* else it is some "other" error,
536              * only return if there was no data processed. */
537             if (ret == 0) {
538                 ret = -1;
539             }
540             break;
541         }
542         i++;
543     }
544     return ret;
545 }
546 
547 ssize_t
548 readv(int fd, const struct iovec *iov, int iov_cnt)
549 {
550     return readv_writev(fd, iov, iov_cnt, false);
551 }
552 
553 ssize_t
554 writev(int fd, const struct iovec *iov, int iov_cnt)
555 {
556     return readv_writev(fd, iov, iov_cnt, true);
557 }
558 #endif
559