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 <termios.h>
  51 #include <unistd.h>
  52
  53 #include <glib/gprintf.h>
  54
  55 #include "config-host.h"
  56 #include "sysemu/sysemu.h"
  57 #include "trace.h"
  58 #include "qemu/sockets.h"
  59 #include <sys/mman.h>
  60
  61 #ifdef CONFIG_LINUX
  62 #include <sys/syscall.h>
  63 #endif
  64
  65 int qemu_get_thread_id(void)
  66 {
  67 #if defined(__linux__)
  68     return syscall(SYS_gettid);
  69 #else
  70     return getpid();
  71 #endif
  72 }
  73
  74 int qemu_daemon(int nochdir, int noclose)
  75 {
  76     return daemon(nochdir, noclose);
  77 }
  78
  79 void *qemu_oom_check(void *ptr)
  80 {
  81     if (ptr == NULL) {
  82         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  83         abort();
  84     }
  85     return ptr;
  86 }
  87
  88 void *qemu_memalign(size_t alignment, size_t size)
  89 {
  90     void *ptr;
  91
  92     if (alignment < sizeof(void*)) {
  93         alignment = sizeof(void*);
  94     }
  95
  96 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  97     int ret;
  98     ret = posix_memalign(&ptr, alignment, size);
  99     if (ret != 0) {
 100         fprintf(stderr, "Failed to allocate %zu B: %s\n",
 101                 size, strerror(ret));
 102         abort();
 103     }
 104 #elif defined(CONFIG_BSD)
 105     ptr = qemu_oom_check(valloc(size));
 106 #else
 107     ptr = qemu_oom_check(memalign(alignment, size));
 108 #endif
 109     trace_qemu_memalign(alignment, size, ptr);
 110     return ptr;
 111 }
 112
 113 /* alloc shared memory pages */
 114 void *qemu_anon_ram_alloc(size_t size)
 115 {
 116     size_t align = QEMU_VMALLOC_ALIGN;
 117     size_t total = size + align - getpagesize();
 118     void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
 119                      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 120     size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
 121
 122     if (ptr == MAP_FAILED) {
 123         return NULL;
 124     }
 125
 126     ptr += offset;
 127     total -= offset;
 128
 129     if (offset > 0) {
 130         munmap(ptr - offset, offset);
 131     }
 132     if (total > size) {
 133         munmap(ptr + size, total - size);
 134     }
 135
 136     trace_qemu_anon_ram_alloc(size, ptr);
 137     return ptr;
 138 }
 139
 140 void qemu_vfree(void *ptr)
 141 {
 142     trace_qemu_vfree(ptr);
 143     free(ptr);
 144 }
 145
 146 void qemu_anon_ram_free(void *ptr, size_t size)
 147 {
 148     trace_qemu_anon_ram_free(ptr, size);
 149     if (ptr) {
 150         munmap(ptr, size);
 151     }
 152 }
 153
 154 void qemu_set_block(int fd)
 155 {
 156     int f;
 157     f = fcntl(fd, F_GETFL);
 158     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 159 }
 160
 161 void qemu_set_nonblock(int fd)
 162 {
 163     int f;
 164     f = fcntl(fd, F_GETFL);
 165     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 166 }
 167
 168 int socket_set_fast_reuse(int fd)
 169 {
 170     int val = 1, ret;
 171
 172     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 173                      (const char *)&val, sizeof(val));
 174
 175     assert(ret == 0);
 176
 177     return ret;
 178 }
 179
 180 void qemu_set_cloexec(int fd)
 181 {
 182     int f;
 183     f = fcntl(fd, F_GETFD);
 184     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 185 }
 186
 187 /*
 188  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 189  */
 190 int qemu_pipe(int pipefd[2])
 191 {
 192     int ret;
 193
 194 #ifdef CONFIG_PIPE2
 195     ret = pipe2(pipefd, O_CLOEXEC);
 196     if (ret != -1 || errno != ENOSYS) {
 197         return ret;
 198     }
 199 #endif
 200     ret = pipe(pipefd);
 201     if (ret == 0) {
 202         qemu_set_cloexec(pipefd[0]);
 203         qemu_set_cloexec(pipefd[1]);
 204     }
 205
 206     return ret;
 207 }
 208
 209 int qemu_utimens(const char *path, const struct timespec *times)
 210 {
 211     struct timeval tv[2], tv_now;
 212     struct stat st;
 213     int i;
 214 #ifdef CONFIG_UTIMENSAT
 215     int ret;
 216
 217     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 218     if (ret != -1 || errno != ENOSYS) {
 219         return ret;
 220     }
 221 #endif
 222     /* Fallback: use utimes() instead of utimensat() */
 223
 224     /* happy if special cases */
 225     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 226         return 0;
 227     }
 228     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 229         return utimes(path, NULL);
 230     }
 231
 232     /* prepare for hard cases */
 233     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 234         gettimeofday(&tv_now, NULL);
 235     }
 236     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 237         stat(path, &st);
 238     }
 239
 240     for (i = 0; i < 2; i++) {
 241         if (times[i].tv_nsec == UTIME_NOW) {
 242             tv[i].tv_sec = tv_now.tv_sec;
 243             tv[i].tv_usec = tv_now.tv_usec;
 244         } else if (times[i].tv_nsec == UTIME_OMIT) {
 245             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 246             tv[i].tv_usec = 0;
 247         } else {
 248             tv[i].tv_sec = times[i].tv_sec;
 249             tv[i].tv_usec = times[i].tv_nsec / 1000;
 250         }
 251     }
 252
 253     return utimes(path, &tv[0]);
 254 }
 255
 256 char *
 257 qemu_get_local_state_pathname(const char *relative_pathname)
 258 {
 259     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 260                            relative_pathname);
 261 }
 262
 263 void qemu_set_tty_echo(int fd, bool echo)
 264 {
 265     struct termios tty;
 266
 267     tcgetattr(fd, &tty);
 268
 269     if (echo) {
 270         tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
 271     } else {
 272         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
 273     }
 274
 275     tcsetattr(fd, TCSANOW, &tty);
 276 }