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 /* 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__) || defined(__arm__))
  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 #elif defined(__linux__) && defined(__s390x__)
  44    /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
  45 #  define QEMU_VMALLOC_ALIGN (256 * 4096)
  46 #else
  47 #  define QEMU_VMALLOC_ALIGN getpagesize()
  48 #endif
  49
  50 #include <glib/gprintf.h>
  51
  52 #include "config-host.h"
  53 #include "sysemu/sysemu.h"
  54 #include "trace.h"
  55 #include "qemu/sockets.h"
  56 #include <sys/mman.h>
  57
  58 #ifdef CONFIG_LINUX
  59 #include <sys/syscall.h>
  60 #endif
  61
  62 int qemu_get_thread_id(void)
  63 {
  64 #if defined(__linux__)
  65     return syscall(SYS_gettid);
  66 #else
  67     return getpid();
  68 #endif
  69 }
  70
  71 int qemu_daemon(int nochdir, int noclose)
  72 {
  73     return daemon(nochdir, noclose);
  74 }
  75
  76 void *qemu_oom_check(void *ptr)
  77 {
  78     if (ptr == NULL) {
  79         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  80         abort();
  81     }
  82     return ptr;
  83 }
  84
  85 void *qemu_memalign(size_t alignment, size_t size)
  86 {
  87     void *ptr;
  88 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  89     int ret;
  90     ret = posix_memalign(&ptr, alignment, size);
  91     if (ret != 0) {
  92         fprintf(stderr, "Failed to allocate %zu B: %s\n",
  93                 size, strerror(ret));
  94         abort();
  95     }
  96 #elif defined(CONFIG_BSD)
  97     ptr = qemu_oom_check(valloc(size));
  98 #else
  99     ptr = qemu_oom_check(memalign(alignment, size));
 100 #endif
 101     trace_qemu_memalign(alignment, size, ptr);
 102     return ptr;
 103 }
 104
 105 /* alloc shared memory pages */
 106 void *qemu_anon_ram_alloc(size_t size)
 107 {
 108     size_t align = QEMU_VMALLOC_ALIGN;
 109     size_t total = size + align - getpagesize();
 110     void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
 111                      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 112     size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
 113
 114     if (ptr == MAP_FAILED) {
 115         return NULL;
 116     }
 117
 118     ptr += offset;
 119     total -= offset;
 120
 121     if (offset > 0) {
 122         munmap(ptr - offset, offset);
 123     }
 124     if (total > size) {
 125         munmap(ptr + size, total - size);
 126     }
 127
 128     trace_qemu_anon_ram_alloc(size, ptr);
 129     return ptr;
 130 }
 131
 132 void qemu_vfree(void *ptr)
 133 {
 134     trace_qemu_vfree(ptr);
 135     free(ptr);
 136 }
 137
 138 void qemu_anon_ram_free(void *ptr, size_t size)
 139 {
 140     trace_qemu_anon_ram_free(ptr, size);
 141     if (ptr) {
 142         munmap(ptr, size);
 143     }
 144 }
 145
 146 void qemu_set_block(int fd)
 147 {
 148     int f;
 149     f = fcntl(fd, F_GETFL);
 150     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 151 }
 152
 153 void qemu_set_nonblock(int fd)
 154 {
 155     int f;
 156     f = fcntl(fd, F_GETFL);
 157     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 158 }
 159
 160 void qemu_set_cloexec(int fd)
 161 {
 162     int f;
 163     f = fcntl(fd, F_GETFD);
 164     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 165 }
 166
 167 /*
 168  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 169  */
 170 int qemu_pipe(int pipefd[2])
 171 {
 172     int ret;
 173
 174 #ifdef CONFIG_PIPE2
 175     ret = pipe2(pipefd, O_CLOEXEC);
 176     if (ret != -1 || errno != ENOSYS) {
 177         return ret;
 178     }
 179 #endif
 180     ret = pipe(pipefd);
 181     if (ret == 0) {
 182         qemu_set_cloexec(pipefd[0]);
 183         qemu_set_cloexec(pipefd[1]);
 184     }
 185
 186     return ret;
 187 }
 188
 189 int qemu_utimens(const char *path, const struct timespec *times)
 190 {
 191     struct timeval tv[2], tv_now;
 192     struct stat st;
 193     int i;
 194 #ifdef CONFIG_UTIMENSAT
 195     int ret;
 196
 197     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 198     if (ret != -1 || errno != ENOSYS) {
 199         return ret;
 200     }
 201 #endif
 202     /* Fallback: use utimes() instead of utimensat() */
 203
 204     /* happy if special cases */
 205     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 206         return 0;
 207     }
 208     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 209         return utimes(path, NULL);
 210     }
 211
 212     /* prepare for hard cases */
 213     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 214         gettimeofday(&tv_now, NULL);
 215     }
 216     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 217         stat(path, &st);
 218     }
 219
 220     for (i = 0; i < 2; i++) {
 221         if (times[i].tv_nsec == UTIME_NOW) {
 222             tv[i].tv_sec = tv_now.tv_sec;
 223             tv[i].tv_usec = tv_now.tv_usec;
 224         } else if (times[i].tv_nsec == UTIME_OMIT) {
 225             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 226             tv[i].tv_usec = 0;
 227         } else {
 228             tv[i].tv_sec = times[i].tv_sec;
 229             tv[i].tv_usec = times[i].tv_nsec / 1000;
 230         }
 231     }
 232
 233     return utimes(path, &tv[0]);
 234 }
 235
 236 char *
 237 qemu_get_local_state_pathname(const char *relative_pathname)
 238 {
 239     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 240                            relative_pathname);
 241 }