File:  [Qemu by Fabrice Bellard] / qemu / oslib-posix.c
Revision 1.1.1.3 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:17:41 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1001, HEAD
qemu 1.0.1

    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__)
   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: #  define CONFIG_VALGRIND
   44: #else
   45: #  define QEMU_VMALLOC_ALIGN getpagesize()
   46: #endif
   47: 
   48: #include "config-host.h"
   49: #include "sysemu.h"
   50: #include "trace.h"
   51: #include "qemu_socket.h"
   52: 
   53: #if defined(CONFIG_VALGRIND)
   54: static int running_on_valgrind = -1;
   55: #else
   56: #  define running_on_valgrind 0
   57: #endif
   58: 
   59: int qemu_daemon(int nochdir, int noclose)
   60: {
   61:     return daemon(nochdir, noclose);
   62: }
   63: 
   64: void *qemu_oom_check(void *ptr)
   65: {
   66:     if (ptr == NULL) {
   67:         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
   68:         abort();
   69:     }
   70:     return ptr;
   71: }
   72: 
   73: void *qemu_memalign(size_t alignment, size_t size)
   74: {
   75:     void *ptr;
   76: #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
   77:     int ret;
   78:     ret = posix_memalign(&ptr, alignment, size);
   79:     if (ret != 0) {
   80:         fprintf(stderr, "Failed to allocate %zu B: %s\n",
   81:                 size, strerror(ret));
   82:         abort();
   83:     }
   84: #elif defined(CONFIG_BSD)
   85:     ptr = qemu_oom_check(valloc(size));
   86: #else
   87:     ptr = qemu_oom_check(memalign(alignment, size));
   88: #endif
   89:     trace_qemu_memalign(alignment, size, ptr);
   90:     return ptr;
   91: }
   92: 
   93: /* alloc shared memory pages */
   94: void *qemu_vmalloc(size_t size)
   95: {
   96:     void *ptr;
   97:     size_t align = QEMU_VMALLOC_ALIGN;
   98: 
   99: #if defined(CONFIG_VALGRIND)
  100:     if (running_on_valgrind < 0) {
  101:         /* First call, test whether we are running on Valgrind.
  102:            This is a substitute for RUNNING_ON_VALGRIND from valgrind.h. */
  103:         const char *ld = getenv("LD_PRELOAD");
  104:         running_on_valgrind = (ld != NULL && strstr(ld, "vgpreload"));
  105:     }
  106: #endif
  107: 
  108:     if (size < align || running_on_valgrind) {
  109:         align = getpagesize();
  110:     }
  111:     ptr = qemu_memalign(align, size);
  112:     trace_qemu_vmalloc(size, ptr);
  113:     return ptr;
  114: }
  115: 
  116: void qemu_vfree(void *ptr)
  117: {
  118:     trace_qemu_vfree(ptr);
  119:     free(ptr);
  120: }
  121: 
  122: void socket_set_block(int fd)
  123: {
  124:     int f;
  125:     f = fcntl(fd, F_GETFL);
  126:     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
  127: }
  128: 
  129: void socket_set_nonblock(int fd)
  130: {
  131:     int f;
  132:     f = fcntl(fd, F_GETFL);
  133:     fcntl(fd, F_SETFL, f | O_NONBLOCK);
  134: }
  135: 
  136: void qemu_set_cloexec(int fd)
  137: {
  138:     int f;
  139:     f = fcntl(fd, F_GETFD);
  140:     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
  141: }
  142: 
  143: /*
  144:  * Creates a pipe with FD_CLOEXEC set on both file descriptors
  145:  */
  146: int qemu_pipe(int pipefd[2])
  147: {
  148:     int ret;
  149: 
  150: #ifdef CONFIG_PIPE2
  151:     ret = pipe2(pipefd, O_CLOEXEC);
  152:     if (ret != -1 || errno != ENOSYS) {
  153:         return ret;
  154:     }
  155: #endif
  156:     ret = pipe(pipefd);
  157:     if (ret == 0) {
  158:         qemu_set_cloexec(pipefd[0]);
  159:         qemu_set_cloexec(pipefd[1]);
  160:     }
  161: 
  162:     return ret;
  163: }
  164: 
  165: int qemu_utimens(const char *path, const struct timespec *times)
  166: {
  167:     struct timeval tv[2], tv_now;
  168:     struct stat st;
  169:     int i;
  170: #ifdef CONFIG_UTIMENSAT
  171:     int ret;
  172: 
  173:     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
  174:     if (ret != -1 || errno != ENOSYS) {
  175:         return ret;
  176:     }
  177: #endif
  178:     /* Fallback: use utimes() instead of utimensat() */
  179: 
  180:     /* happy if special cases */
  181:     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
  182:         return 0;
  183:     }
  184:     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
  185:         return utimes(path, NULL);
  186:     }
  187: 
  188:     /* prepare for hard cases */
  189:     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
  190:         gettimeofday(&tv_now, NULL);
  191:     }
  192:     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
  193:         stat(path, &st);
  194:     }
  195: 
  196:     for (i = 0; i < 2; i++) {
  197:         if (times[i].tv_nsec == UTIME_NOW) {
  198:             tv[i].tv_sec = tv_now.tv_sec;
  199:             tv[i].tv_usec = tv_now.tv_usec;
  200:         } else if (times[i].tv_nsec == UTIME_OMIT) {
  201:             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
  202:             tv[i].tv_usec = 0;
  203:         } else {
  204:             tv[i].tv_sec = times[i].tv_sec;
  205:             tv[i].tv_usec = times[i].tv_nsec / 1000;
  206:         }
  207:     }
  208: 
  209:     return utimes(path, &tv[0]);
  210: }

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