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 /* The following block of code temporarily renames the daemon() function so the
  30    compiler does not see the warning associated with it in stdlib.h on OSX */
  31 #ifdef __APPLE__
  32 #define daemon qemu_fake_daemon_function
  33 #include <stdlib.h>
  34 #undef daemon
  35 extern int daemon(int, int);
  36 #endif
  37
  38 #if defined(__linux__) && defined(__x86_64__)
  39    /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
  40       Valgrind does not support alignments larger than 1 MiB,
  41       therefore we need special code which handles running on Valgrind. */
  42 #  define QEMU_VMALLOC_ALIGN (512 * 4096)
  43 #  define CONFIG_VALGRIND
  44 #else
  45 #  define QEMU_VMALLOC_ALIGN getpagesize()
  46 #endif
  47
  48 #include "config-host.h"
  49 #include "sysemu.h"
  50 #include "trace.h"
  51 #include "qemu_socket.h"
  52
  53 #if defined(CONFIG_VALGRIND)
  54 static int running_on_valgrind = -1;
  55 #else
  56 #  define running_on_valgrind 0
  57 #endif
  58
  59 int qemu_daemon(int nochdir, int noclose)
  60 {
  61     return daemon(nochdir, noclose);
  62 }
  63
  64 void *qemu_oom_check(void *ptr)
  65 {
  66     if (ptr == NULL) {
  67         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  68         abort();
  69     }
  70     return ptr;
  71 }
  72
  73 void *qemu_memalign(size_t alignment, size_t size)
  74 {
  75     void *ptr;
  76 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  77     int ret;
  78     ret = posix_memalign(&ptr, alignment, size);
  79     if (ret != 0) {
  80         fprintf(stderr, "Failed to allocate %zu B: %s\n",
  81                 size, strerror(ret));
  82         abort();
  83     }
  84 #elif defined(CONFIG_BSD)
  85     ptr = qemu_oom_check(valloc(size));
  86 #else
  87     ptr = qemu_oom_check(memalign(alignment, size));
  88 #endif
  89     trace_qemu_memalign(alignment, size, ptr);
  90     return ptr;
  91 }
  92
  93 /* alloc shared memory pages */
  94 void *qemu_vmalloc(size_t size)
  95 {
  96     void *ptr;
  97     size_t align = QEMU_VMALLOC_ALIGN;
  98
  99 #if defined(CONFIG_VALGRIND)
 100     if (running_on_valgrind < 0) {
 101         /* First call, test whether we are running on Valgrind.
 102            This is a substitute for RUNNING_ON_VALGRIND from valgrind.h. */
 103         const char *ld = getenv("LD_PRELOAD");
 104         running_on_valgrind = (ld != NULL && strstr(ld, "vgpreload"));
 105     }
 106 #endif
 107
 108     if (size < align || running_on_valgrind) {
 109         align = getpagesize();
 110     }
 111     ptr = qemu_memalign(align, size);
 112     trace_qemu_vmalloc(size, ptr);
 113     return ptr;
 114 }
 115
 116 void qemu_vfree(void *ptr)
 117 {
 118     trace_qemu_vfree(ptr);
 119     free(ptr);
 120 }
 121
 122 void socket_set_block(int fd)
 123 {
 124     int f;
 125     f = fcntl(fd, F_GETFL);
 126     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 127 }
 128
 129 void socket_set_nonblock(int fd)
 130 {
 131     int f;
 132     f = fcntl(fd, F_GETFL);
 133     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 134 }
 135
 136 void qemu_set_cloexec(int fd)
 137 {
 138     int f;
 139     f = fcntl(fd, F_GETFD);
 140     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 141 }
 142
 143 /*
 144  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 145  */
 146 int qemu_pipe(int pipefd[2])
 147 {
 148     int ret;
 149
 150 #ifdef CONFIG_PIPE2
 151     ret = pipe2(pipefd, O_CLOEXEC);
 152     if (ret != -1 || errno != ENOSYS) {
 153         return ret;
 154     }
 155 #endif
 156     ret = pipe(pipefd);
 157     if (ret == 0) {
 158         qemu_set_cloexec(pipefd[0]);
 159         qemu_set_cloexec(pipefd[1]);
 160     }
 161
 162     return ret;
 163 }
 164
 165 int qemu_utimens(const char *path, const struct timespec *times)
 166 {
 167     struct timeval tv[2], tv_now;
 168     struct stat st;
 169     int i;
 170 #ifdef CONFIG_UTIMENSAT
 171     int ret;
 172
 173     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 174     if (ret != -1 || errno != ENOSYS) {
 175         return ret;
 176     }
 177 #endif
 178     /* Fallback: use utimes() instead of utimensat() */
 179
 180     /* happy if special cases */
 181     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 182         return 0;
 183     }
 184     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 185         return utimes(path, NULL);
 186     }
 187
 188     /* prepare for hard cases */
 189     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 190         gettimeofday(&tv_now, NULL);
 191     }
 192     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 193         stat(path, &st);
 194     }
 195
 196     for (i = 0; i < 2; i++) {
 197         if (times[i].tv_nsec == UTIME_NOW) {
 198             tv[i].tv_sec = tv_now.tv_sec;
 199             tv[i].tv_usec = tv_now.tv_usec;
 200         } else if (times[i].tv_nsec == UTIME_OMIT) {
 201             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 202             tv[i].tv_usec = 0;
 203         } else {
 204             tv[i].tv_sec = times[i].tv_sec;
 205             tv[i].tv_usec = times[i].tv_nsec / 1000;
 206         }
 207     }
 208
 209     return utimes(path, &tv[0]);
 210 }