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 2MB alignment so transparent hugepages can be used by KVM */
  40 #  define QEMU_VMALLOC_ALIGN (512 * 4096)
  41 #else
  42 #  define QEMU_VMALLOC_ALIGN getpagesize()
  43 #endif
  44
  45 #include "config-host.h"
  46 #include "sysemu.h"
  47 #include "trace.h"
  48 #include "qemu_socket.h"
  49
  50
  51
  52 int qemu_daemon(int nochdir, int noclose)
  53 {
  54     return daemon(nochdir, noclose);
  55 }
  56
  57 void *qemu_oom_check(void *ptr)
  58 {
  59     if (ptr == NULL) {
  60         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  61         abort();
  62     }
  63     return ptr;
  64 }
  65
  66 void *qemu_memalign(size_t alignment, size_t size)
  67 {
  68     void *ptr;
  69 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  70     int ret;
  71     ret = posix_memalign(&ptr, alignment, size);
  72     if (ret != 0) {
  73         fprintf(stderr, "Failed to allocate %zu B: %s\n",
  74                 size, strerror(ret));
  75         abort();
  76     }
  77 #elif defined(CONFIG_BSD)
  78     ptr = qemu_oom_check(valloc(size));
  79 #else
  80     ptr = qemu_oom_check(memalign(alignment, size));
  81 #endif
  82     trace_qemu_memalign(alignment, size, ptr);
  83     return ptr;
  84 }
  85
  86 /* alloc shared memory pages */
  87 void *qemu_vmalloc(size_t size)
  88 {
  89     void *ptr;
  90     size_t align = QEMU_VMALLOC_ALIGN;
  91
  92     if (size < align) {
  93         align = getpagesize();
  94     }
  95     ptr = qemu_memalign(align, size);
  96     trace_qemu_vmalloc(size, ptr);
  97     return ptr;
  98 }
  99
 100 void qemu_vfree(void *ptr)
 101 {
 102     trace_qemu_vfree(ptr);
 103     free(ptr);
 104 }
 105
 106 void socket_set_nonblock(int fd)
 107 {
 108     int f;
 109     f = fcntl(fd, F_GETFL);
 110     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 111 }
 112
 113 void qemu_set_cloexec(int fd)
 114 {
 115     int f;
 116     f = fcntl(fd, F_GETFD);
 117     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 118 }
 119
 120 /*
 121  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 122  */
 123 int qemu_pipe(int pipefd[2])
 124 {
 125     int ret;
 126
 127 #ifdef CONFIG_PIPE2
 128     ret = pipe2(pipefd, O_CLOEXEC);
 129     if (ret != -1 || errno != ENOSYS) {
 130         return ret;
 131     }
 132 #endif
 133     ret = pipe(pipefd);
 134     if (ret == 0) {
 135         qemu_set_cloexec(pipefd[0]);
 136         qemu_set_cloexec(pipefd[1]);
 137     }
 138
 139     return ret;
 140 }
 141
 142 int qemu_utimensat(int dirfd, const char *path, const struct timespec *times,
 143                    int flags)
 144 {
 145     struct timeval tv[2], tv_now;
 146     struct stat st;
 147     int i;
 148 #ifdef CONFIG_UTIMENSAT
 149     int ret;
 150
 151     ret = utimensat(dirfd, path, times, flags);
 152     if (ret != -1 || errno != ENOSYS) {
 153         return ret;
 154     }
 155 #endif
 156     /* Fallback: use utimes() instead of utimensat() */
 157
 158     /* happy if special cases */
 159     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 160         return 0;
 161     }
 162     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 163         return utimes(path, NULL);
 164     }
 165
 166     /* prepare for hard cases */
 167     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 168         gettimeofday(&tv_now, NULL);
 169     }
 170     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 171         stat(path, &st);
 172     }
 173
 174     for (i = 0; i < 2; i++) {
 175         if (times[i].tv_nsec == UTIME_NOW) {
 176             tv[i].tv_sec = tv_now.tv_sec;
 177             tv[i].tv_usec = tv_now.tv_usec;
 178         } else if (times[i].tv_nsec == UTIME_OMIT) {
 179             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 180             tv[i].tv_usec = 0;
 181         } else {
 182             tv[i].tv_sec = times[i].tv_sec;
 183             tv[i].tv_usec = times[i].tv_nsec / 1000;
 184         }
 185     }
 186
 187     return utimes(path, &tv[0]);
 188 }