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 #define HUGETLBFS_MAGIC       0x958458f6
  50
  51 #include <termios.h>
  52 #include <unistd.h>
  53 #include <termios.h>
  54
  55 #include <glib/gprintf.h>
  56
  57 #include "config-host.h"
  58 #include "sysemu/sysemu.h"
  59 #include "trace.h"
  60 #include "qemu/sockets.h"
  61 #include <sys/mman.h>
  62 #include <libgen.h>
  63 #include <setjmp.h>
  64 #include <sys/signal.h>
  65
  66 #ifdef CONFIG_LINUX
  67 #include <sys/syscall.h>
  68 #include <sys/vfs.h>
  69 #endif
  70
  71 #ifdef __FreeBSD__
  72 #include <sys/sysctl.h>
  73 #endif
  74
  75 int qemu_get_thread_id(void)
  76 {
  77 #if defined(__linux__)
  78     return syscall(SYS_gettid);
  79 #else
  80     return getpid();
  81 #endif
  82 }
  83
  84 int qemu_daemon(int nochdir, int noclose)
  85 {
  86     return daemon(nochdir, noclose);
  87 }
  88
  89 void *qemu_oom_check(void *ptr)
  90 {
  91     if (ptr == NULL) {
  92         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  93         abort();
  94     }
  95     return ptr;
  96 }
  97
  98 void *qemu_try_memalign(size_t alignment, size_t size)
  99 {
 100     void *ptr;
 101
 102     if (alignment < sizeof(void*)) {
 103         alignment = sizeof(void*);
 104     }
 105
 106 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
 107     int ret;
 108     ret = posix_memalign(&ptr, alignment, size);
 109     if (ret != 0) {
 110         errno = ret;
 111         ptr = NULL;
 112     }
 113 #elif defined(CONFIG_BSD)
 114     ptr = valloc(size);
 115 #else
 116     ptr = memalign(alignment, size);
 117 #endif
 118     trace_qemu_memalign(alignment, size, ptr);
 119     return ptr;
 120 }
 121
 122 void *qemu_memalign(size_t alignment, size_t size)
 123 {
 124     return qemu_oom_check(qemu_try_memalign(alignment, size));
 125 }
 126
 127 /* alloc shared memory pages */
 128 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
 129 {
 130     size_t align = QEMU_VMALLOC_ALIGN;
 131     size_t total = size + align - getpagesize();
 132     void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
 133                      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 134     size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
 135
 136     if (ptr == MAP_FAILED) {
 137         return NULL;
 138     }
 139
 140     if (alignment) {
 141         *alignment = align;
 142     }
 143     ptr += offset;
 144     total -= offset;
 145
 146     if (offset > 0) {
 147         munmap(ptr - offset, offset);
 148     }
 149     if (total > size) {
 150         munmap(ptr + size, total - size);
 151     }
 152
 153     trace_qemu_anon_ram_alloc(size, ptr);
 154     return ptr;
 155 }
 156
 157 void qemu_vfree(void *ptr)
 158 {
 159     trace_qemu_vfree(ptr);
 160     free(ptr);
 161 }
 162
 163 void qemu_anon_ram_free(void *ptr, size_t size)
 164 {
 165     trace_qemu_anon_ram_free(ptr, size);
 166     if (ptr) {
 167         munmap(ptr, size);
 168     }
 169 }
 170
 171 void qemu_set_block(int fd)
 172 {
 173     int f;
 174     f = fcntl(fd, F_GETFL);
 175     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 176 }
 177
 178 void qemu_set_nonblock(int fd)
 179 {
 180     int f;
 181     f = fcntl(fd, F_GETFL);
 182     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 183 }
 184
 185 int socket_set_fast_reuse(int fd)
 186 {
 187     int val = 1, ret;
 188
 189     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 190                      (const char *)&val, sizeof(val));
 191
 192     assert(ret == 0);
 193
 194     return ret;
 195 }
 196
 197 void qemu_set_cloexec(int fd)
 198 {
 199     int f;
 200     f = fcntl(fd, F_GETFD);
 201     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 202 }
 203
 204 /*
 205  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 206  */
 207 int qemu_pipe(int pipefd[2])
 208 {
 209     int ret;
 210
 211 #ifdef CONFIG_PIPE2
 212     ret = pipe2(pipefd, O_CLOEXEC);
 213     if (ret != -1 || errno != ENOSYS) {
 214         return ret;
 215     }
 216 #endif
 217     ret = pipe(pipefd);
 218     if (ret == 0) {
 219         qemu_set_cloexec(pipefd[0]);
 220         qemu_set_cloexec(pipefd[1]);
 221     }
 222
 223     return ret;
 224 }
 225
 226 int qemu_utimens(const char *path, const struct timespec *times)
 227 {
 228     struct timeval tv[2], tv_now;
 229     struct stat st;
 230     int i;
 231 #ifdef CONFIG_UTIMENSAT
 232     int ret;
 233
 234     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 235     if (ret != -1 || errno != ENOSYS) {
 236         return ret;
 237     }
 238 #endif
 239     /* Fallback: use utimes() instead of utimensat() */
 240
 241     /* happy if special cases */
 242     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 243         return 0;
 244     }
 245     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 246         return utimes(path, NULL);
 247     }
 248
 249     /* prepare for hard cases */
 250     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 251         gettimeofday(&tv_now, NULL);
 252     }
 253     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 254         stat(path, &st);
 255     }
 256
 257     for (i = 0; i < 2; i++) {
 258         if (times[i].tv_nsec == UTIME_NOW) {
 259             tv[i].tv_sec = tv_now.tv_sec;
 260             tv[i].tv_usec = tv_now.tv_usec;
 261         } else if (times[i].tv_nsec == UTIME_OMIT) {
 262             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 263             tv[i].tv_usec = 0;
 264         } else {
 265             tv[i].tv_sec = times[i].tv_sec;
 266             tv[i].tv_usec = times[i].tv_nsec / 1000;
 267         }
 268     }
 269
 270     return utimes(path, &tv[0]);
 271 }
 272
 273 char *
 274 qemu_get_local_state_pathname(const char *relative_pathname)
 275 {
 276     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 277                            relative_pathname);
 278 }
 279
 280 void qemu_set_tty_echo(int fd, bool echo)
 281 {
 282     struct termios tty;
 283
 284     tcgetattr(fd, &tty);
 285
 286     if (echo) {
 287         tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
 288     } else {
 289         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
 290     }
 291
 292     tcsetattr(fd, TCSANOW, &tty);
 293 }
 294
 295 static char exec_dir[PATH_MAX];
 296
 297 void qemu_init_exec_dir(const char *argv0)
 298 {
 299     char *dir;
 300     char *p = NULL;
 301     char buf[PATH_MAX];
 302
 303     assert(!exec_dir[0]);
 304
 305 #if defined(__linux__)
 306     {
 307         int len;
 308         len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
 309         if (len > 0) {
 310             buf[len] = 0;
 311             p = buf;
 312         }
 313     }
 314 #elif defined(__FreeBSD__)
 315     {
 316         static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
 317         size_t len = sizeof(buf) - 1;
 318
 319         *buf = '\0';
 320         if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
 321             *buf) {
 322             buf[sizeof(buf) - 1] = '\0';
 323             p = buf;
 324         }
 325     }
 326 #endif
 327     /* If we don't have any way of figuring out the actual executable
 328        location then try argv[0].  */
 329     if (!p) {
 330         if (!argv0) {
 331             return;
 332         }
 333         p = realpath(argv0, buf);
 334         if (!p) {
 335             return;
 336         }
 337     }
 338     dir = dirname(p);
 339
 340     pstrcpy(exec_dir, sizeof(exec_dir), dir);
 341 }
 342
 343 char *qemu_get_exec_dir(void)
 344 {
 345     return g_strdup(exec_dir);
 346 }
 347
 348 static sigjmp_buf sigjump;
 349
 350 static void sigbus_handler(int signal)
 351 {
 352     siglongjmp(sigjump, 1);
 353 }
 354
 355 static size_t fd_getpagesize(int fd)
 356 {
 357 #ifdef CONFIG_LINUX
 358     struct statfs fs;
 359     int ret;
 360
 361     if (fd != -1) {
 362         do {
 363             ret = fstatfs(fd, &fs);
 364         } while (ret != 0 && errno == EINTR);
 365
 366         if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) {
 367             return fs.f_bsize;
 368         }
 369     }
 370 #endif
 371
 372     return getpagesize();
 373 }
 374
 375 void os_mem_prealloc(int fd, char *area, size_t memory)
 376 {
 377     int ret;
 378     struct sigaction act, oldact;
 379     sigset_t set, oldset;
 380
 381     memset(&act, 0, sizeof(act));
 382     act.sa_handler = &sigbus_handler;
 383     act.sa_flags = 0;
 384
 385     ret = sigaction(SIGBUS, &act, &oldact);
 386     if (ret) {
 387         perror("os_mem_prealloc: failed to install signal handler");
 388         exit(1);
 389     }
 390
 391     /* unblock SIGBUS */
 392     sigemptyset(&set);
 393     sigaddset(&set, SIGBUS);
 394     pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
 395
 396     if (sigsetjmp(sigjump, 1)) {
 397         fprintf(stderr, "os_mem_prealloc: Insufficient free host memory "
 398                         "pages available to allocate guest RAM\n");
 399         exit(1);
 400     } else {
 401         int i;
 402         size_t hpagesize = fd_getpagesize(fd);
 403         size_t numpages = DIV_ROUND_UP(memory, hpagesize);
 404
 405         /* MAP_POPULATE silently ignores failures */
 406         for (i = 0; i < numpages; i++) {
 407             memset(area + (hpagesize * i), 0, 1);
 408         }
 409
 410         ret = sigaction(SIGBUS, &oldact, NULL);
 411         if (ret) {
 412             perror("os_mem_prealloc: failed to reinstall signal handler");
 413             exit(1);
 414         }
 415
 416         pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 417     }
 418 }
 419
 420
 421 static struct termios oldtty;
 422
 423 static void term_exit(void)
 424 {
 425     tcsetattr(0, TCSANOW, &oldtty);
 426 }
 427
 428 static void term_init(void)
 429 {
 430     struct termios tty;
 431
 432     tcgetattr(0, &tty);
 433     oldtty = tty;
 434
 435     tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
 436                           |INLCR|IGNCR|ICRNL|IXON);
 437     tty.c_oflag |= OPOST;
 438     tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
 439     tty.c_cflag &= ~(CSIZE|PARENB);
 440     tty.c_cflag |= CS8;
 441     tty.c_cc[VMIN] = 1;
 442     tty.c_cc[VTIME] = 0;
 443
 444     tcsetattr(0, TCSANOW, &tty);
 445
 446     atexit(term_exit);
 447 }
 448
 449 int qemu_read_password(char *buf, int buf_size)
 450 {
 451     uint8_t ch;
 452     int i, ret;
 453
 454     printf("password: ");
 455     fflush(stdout);
 456     term_init();
 457     i = 0;
 458     for (;;) {
 459         ret = read(0, &ch, 1);
 460         if (ret == -1) {
 461             if (errno == EAGAIN || errno == EINTR) {
 462                 continue;
 463             } else {
 464                 break;
 465             }
 466         } else if (ret == 0) {
 467             ret = -1;
 468             break;
 469         } else {
 470             if (ch == '\r' ||
 471                 ch == '\n') {
 472                 ret = 0;
 473                 break;
 474             }
 475             if (i < (buf_size - 1)) {
 476                 buf[i++] = ch;
 477             }
 478         }
 479     }
 480     term_exit();
 481     buf[i] = '\0';
 482     printf("\n");
 483     return ret;
 484 }