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 #ifdef __FreeBSD__
  67 #include <sys/sysctl.h>
  68 #endif
  69
  70 int qemu_get_thread_id(void)
  71 {
  72 #if defined(__linux__)
  73     return syscall(SYS_gettid);
  74 #else
  75     return getpid();
  76 #endif
  77 }
  78
  79 int qemu_daemon(int nochdir, int noclose)
  80 {
  81     return daemon(nochdir, noclose);
  82 }
  83
  84 void *qemu_oom_check(void *ptr)
  85 {
  86     if (ptr == NULL) {
  87         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  88         abort();
  89     }
  90     return ptr;
  91 }
  92
  93 void *qemu_memalign(size_t alignment, size_t size)
  94 {
  95     void *ptr;
  96
  97     if (alignment < sizeof(void*)) {
  98         alignment = sizeof(void*);
  99     }
 100
 101 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
 102     int ret;
 103     ret = posix_memalign(&ptr, alignment, size);
 104     if (ret != 0) {
 105         fprintf(stderr, "Failed to allocate %zu B: %s\n",
 106                 size, strerror(ret));
 107         abort();
 108     }
 109 #elif defined(CONFIG_BSD)
 110     ptr = qemu_oom_check(valloc(size));
 111 #else
 112     ptr = qemu_oom_check(memalign(alignment, size));
 113 #endif
 114     trace_qemu_memalign(alignment, size, ptr);
 115     return ptr;
 116 }
 117
 118 /* alloc shared memory pages */
 119 void *qemu_anon_ram_alloc(size_t size)
 120 {
 121     size_t align = QEMU_VMALLOC_ALIGN;
 122     size_t total = size + align - getpagesize();
 123     void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
 124                      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 125     size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
 126
 127     if (ptr == MAP_FAILED) {
 128         return NULL;
 129     }
 130
 131     ptr += offset;
 132     total -= offset;
 133
 134     if (offset > 0) {
 135         munmap(ptr - offset, offset);
 136     }
 137     if (total > size) {
 138         munmap(ptr + size, total - size);
 139     }
 140
 141     trace_qemu_anon_ram_alloc(size, ptr);
 142     return ptr;
 143 }
 144
 145 void qemu_vfree(void *ptr)
 146 {
 147     trace_qemu_vfree(ptr);
 148     free(ptr);
 149 }
 150
 151 void qemu_anon_ram_free(void *ptr, size_t size)
 152 {
 153     trace_qemu_anon_ram_free(ptr, size);
 154     if (ptr) {
 155         munmap(ptr, size);
 156     }
 157 }
 158
 159 void qemu_set_block(int fd)
 160 {
 161     int f;
 162     f = fcntl(fd, F_GETFL);
 163     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 164 }
 165
 166 void qemu_set_nonblock(int fd)
 167 {
 168     int f;
 169     f = fcntl(fd, F_GETFL);
 170     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 171 }
 172
 173 int socket_set_fast_reuse(int fd)
 174 {
 175     int val = 1, ret;
 176
 177     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 178                      (const char *)&val, sizeof(val));
 179
 180     assert(ret == 0);
 181
 182     return ret;
 183 }
 184
 185 void qemu_set_cloexec(int fd)
 186 {
 187     int f;
 188     f = fcntl(fd, F_GETFD);
 189     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 190 }
 191
 192 /*
 193  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 194  */
 195 int qemu_pipe(int pipefd[2])
 196 {
 197     int ret;
 198
 199 #ifdef CONFIG_PIPE2
 200     ret = pipe2(pipefd, O_CLOEXEC);
 201     if (ret != -1 || errno != ENOSYS) {
 202         return ret;
 203     }
 204 #endif
 205     ret = pipe(pipefd);
 206     if (ret == 0) {
 207         qemu_set_cloexec(pipefd[0]);
 208         qemu_set_cloexec(pipefd[1]);
 209     }
 210
 211     return ret;
 212 }
 213
 214 int qemu_utimens(const char *path, const struct timespec *times)
 215 {
 216     struct timeval tv[2], tv_now;
 217     struct stat st;
 218     int i;
 219 #ifdef CONFIG_UTIMENSAT
 220     int ret;
 221
 222     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 223     if (ret != -1 || errno != ENOSYS) {
 224         return ret;
 225     }
 226 #endif
 227     /* Fallback: use utimes() instead of utimensat() */
 228
 229     /* happy if special cases */
 230     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 231         return 0;
 232     }
 233     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 234         return utimes(path, NULL);
 235     }
 236
 237     /* prepare for hard cases */
 238     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 239         gettimeofday(&tv_now, NULL);
 240     }
 241     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 242         stat(path, &st);
 243     }
 244
 245     for (i = 0; i < 2; i++) {
 246         if (times[i].tv_nsec == UTIME_NOW) {
 247             tv[i].tv_sec = tv_now.tv_sec;
 248             tv[i].tv_usec = tv_now.tv_usec;
 249         } else if (times[i].tv_nsec == UTIME_OMIT) {
 250             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 251             tv[i].tv_usec = 0;
 252         } else {
 253             tv[i].tv_sec = times[i].tv_sec;
 254             tv[i].tv_usec = times[i].tv_nsec / 1000;
 255         }
 256     }
 257
 258     return utimes(path, &tv[0]);
 259 }
 260
 261 char *
 262 qemu_get_local_state_pathname(const char *relative_pathname)
 263 {
 264     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 265                            relative_pathname);
 266 }
 267
 268 void qemu_set_tty_echo(int fd, bool echo)
 269 {
 270     struct termios tty;
 271
 272     tcgetattr(fd, &tty);
 273
 274     if (echo) {
 275         tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
 276     } else {
 277         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
 278     }
 279
 280     tcsetattr(fd, TCSANOW, &tty);
 281 }
 282
 283 static char exec_dir[PATH_MAX];
 284
 285 void qemu_init_exec_dir(const char *argv0)
 286 {
 287     char *dir;
 288     char *p = NULL;
 289     char buf[PATH_MAX];
 290
 291     assert(!exec_dir[0]);
 292
 293 #if defined(__linux__)
 294     {
 295         int len;
 296         len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
 297         if (len > 0) {
 298             buf[len] = 0;
 299             p = buf;
 300         }
 301     }
 302 #elif defined(__FreeBSD__)
 303     {
 304         static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
 305         size_t len = sizeof(buf) - 1;
 306
 307         *buf = '\0';
 308         if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
 309             *buf) {
 310             buf[sizeof(buf) - 1] = '\0';
 311             p = buf;
 312         }
 313     }
 314 #endif
 315     /* If we don't have any way of figuring out the actual executable
 316        location then try argv[0].  */
 317     if (!p) {
 318         if (!argv0) {
 319             return;
 320         }
 321         p = realpath(argv0, buf);
 322         if (!p) {
 323             return;
 324         }
 325     }
 326     dir = dirname(p);
 327
 328     pstrcpy(exec_dir, sizeof(exec_dir), dir);
 329 }
 330
 331 char *qemu_get_exec_dir(void)
 332 {
 333     return g_strdup(exec_dir);
 334 }