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 #include <libgen.h>
  61
  62 #ifdef CONFIG_LINUX
  63 #include <sys/syscall.h>
  64 #endif
  65
  66 int qemu_get_thread_id(void)
  67 {
  68 #if defined(__linux__)
  69     return syscall(SYS_gettid);
  70 #else
  71     return getpid();
  72 #endif
  73 }
  74
  75 int qemu_daemon(int nochdir, int noclose)
  76 {
  77     return daemon(nochdir, noclose);
  78 }
  79
  80 void *qemu_oom_check(void *ptr)
  81 {
  82     if (ptr == NULL) {
  83         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  84         abort();
  85     }
  86     return ptr;
  87 }
  88
  89 void *qemu_memalign(size_t alignment, size_t size)
  90 {
  91     void *ptr;
  92
  93     if (alignment < sizeof(void*)) {
  94         alignment = sizeof(void*);
  95     }
  96
  97 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  98     int ret;
  99     ret = posix_memalign(&ptr, alignment, size);
 100     if (ret != 0) {
 101         fprintf(stderr, "Failed to allocate %zu B: %s\n",
 102                 size, strerror(ret));
 103         abort();
 104     }
 105 #elif defined(CONFIG_BSD)
 106     ptr = qemu_oom_check(valloc(size));
 107 #else
 108     ptr = qemu_oom_check(memalign(alignment, size));
 109 #endif
 110     trace_qemu_memalign(alignment, size, ptr);
 111     return ptr;
 112 }
 113
 114 /* alloc shared memory pages */
 115 void *qemu_anon_ram_alloc(size_t size)
 116 {
 117     size_t align = QEMU_VMALLOC_ALIGN;
 118     size_t total = size + align - getpagesize();
 119     void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
 120                      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 121     size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
 122
 123     if (ptr == MAP_FAILED) {
 124         return NULL;
 125     }
 126
 127     ptr += offset;
 128     total -= offset;
 129
 130     if (offset > 0) {
 131         munmap(ptr - offset, offset);
 132     }
 133     if (total > size) {
 134         munmap(ptr + size, total - size);
 135     }
 136
 137     trace_qemu_anon_ram_alloc(size, ptr);
 138     return ptr;
 139 }
 140
 141 void qemu_vfree(void *ptr)
 142 {
 143     trace_qemu_vfree(ptr);
 144     free(ptr);
 145 }
 146
 147 void qemu_anon_ram_free(void *ptr, size_t size)
 148 {
 149     trace_qemu_anon_ram_free(ptr, size);
 150     if (ptr) {
 151         munmap(ptr, size);
 152     }
 153 }
 154
 155 void qemu_set_block(int fd)
 156 {
 157     int f;
 158     f = fcntl(fd, F_GETFL);
 159     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 160 }
 161
 162 void qemu_set_nonblock(int fd)
 163 {
 164     int f;
 165     f = fcntl(fd, F_GETFL);
 166     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 167 }
 168
 169 int socket_set_fast_reuse(int fd)
 170 {
 171     int val = 1, ret;
 172
 173     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 174                      (const char *)&val, sizeof(val));
 175
 176     assert(ret == 0);
 177
 178     return ret;
 179 }
 180
 181 void qemu_set_cloexec(int fd)
 182 {
 183     int f;
 184     f = fcntl(fd, F_GETFD);
 185     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 186 }
 187
 188 /*
 189  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 190  */
 191 int qemu_pipe(int pipefd[2])
 192 {
 193     int ret;
 194
 195 #ifdef CONFIG_PIPE2
 196     ret = pipe2(pipefd, O_CLOEXEC);
 197     if (ret != -1 || errno != ENOSYS) {
 198         return ret;
 199     }
 200 #endif
 201     ret = pipe(pipefd);
 202     if (ret == 0) {
 203         qemu_set_cloexec(pipefd[0]);
 204         qemu_set_cloexec(pipefd[1]);
 205     }
 206
 207     return ret;
 208 }
 209
 210 int qemu_utimens(const char *path, const struct timespec *times)
 211 {
 212     struct timeval tv[2], tv_now;
 213     struct stat st;
 214     int i;
 215 #ifdef CONFIG_UTIMENSAT
 216     int ret;
 217
 218     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 219     if (ret != -1 || errno != ENOSYS) {
 220         return ret;
 221     }
 222 #endif
 223     /* Fallback: use utimes() instead of utimensat() */
 224
 225     /* happy if special cases */
 226     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 227         return 0;
 228     }
 229     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 230         return utimes(path, NULL);
 231     }
 232
 233     /* prepare for hard cases */
 234     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 235         gettimeofday(&tv_now, NULL);
 236     }
 237     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 238         stat(path, &st);
 239     }
 240
 241     for (i = 0; i < 2; i++) {
 242         if (times[i].tv_nsec == UTIME_NOW) {
 243             tv[i].tv_sec = tv_now.tv_sec;
 244             tv[i].tv_usec = tv_now.tv_usec;
 245         } else if (times[i].tv_nsec == UTIME_OMIT) {
 246             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 247             tv[i].tv_usec = 0;
 248         } else {
 249             tv[i].tv_sec = times[i].tv_sec;
 250             tv[i].tv_usec = times[i].tv_nsec / 1000;
 251         }
 252     }
 253
 254     return utimes(path, &tv[0]);
 255 }
 256
 257 char *
 258 qemu_get_local_state_pathname(const char *relative_pathname)
 259 {
 260     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 261                            relative_pathname);
 262 }
 263
 264 void qemu_set_tty_echo(int fd, bool echo)
 265 {
 266     struct termios tty;
 267
 268     tcgetattr(fd, &tty);
 269
 270     if (echo) {
 271         tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
 272     } else {
 273         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
 274     }
 275
 276     tcsetattr(fd, TCSANOW, &tty);
 277 }
 278
 279 static char exec_dir[PATH_MAX];
 280
 281 void qemu_init_exec_dir(const char *argv0)
 282 {
 283     char *dir;
 284     char *p = NULL;
 285     char buf[PATH_MAX];
 286
 287     assert(!exec_dir[0]);
 288
 289 #if defined(__linux__)
 290     {
 291         int len;
 292         len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
 293         if (len > 0) {
 294             buf[len] = 0;
 295             p = buf;
 296         }
 297     }
 298 #elif defined(__FreeBSD__)
 299     {
 300         static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
 301         size_t len = sizeof(buf) - 1;
 302
 303         *buf = '\0';
 304         if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
 305             *buf) {
 306             buf[sizeof(buf) - 1] = '\0';
 307             p = buf;
 308         }
 309     }
 310 #endif
 311     /* If we don't have any way of figuring out the actual executable
 312        location then try argv[0].  */
 313     if (!p) {
 314         if (!argv0) {
 315             return;
 316         }
 317         p = realpath(argv0, buf);
 318         if (!p) {
 319             return;
 320         }
 321     }
 322     dir = dirname(p);
 323
 324     pstrcpy(exec_dir, sizeof(exec_dir), dir);
 325 }
 326
 327 char *qemu_get_exec_dir(void)
 328 {
 329     return g_strdup(exec_dir);
 330 }