os-posix.c

   1 /*
   2  * os-posix.c
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2010 Red Hat, Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include <unistd.h>
  27 #include <fcntl.h>
  28 #include <signal.h>
  29 #include <sys/types.h>
  30 #include <sys/wait.h>
  31 #include <libgen.h>
  32
  33 /* Needed early for CONFIG_BSD etc. */
  34 #include "config-host.h"
  35 #include "sysemu.h"
  36
  37 void os_setup_early_signal_handling(void)
  38 {
  39     struct sigaction act;
  40     sigfillset(&act.sa_mask);
  41     act.sa_flags = 0;
  42     act.sa_handler = SIG_IGN;
  43     sigaction(SIGPIPE, &act, NULL);
  44 }
  45
  46 static void termsig_handler(int signal)
  47 {
  48     qemu_system_shutdown_request();
  49 }
  50
  51 static void sigchld_handler(int signal)
  52 {
  53     waitpid(-1, NULL, WNOHANG);
  54 }
  55
  56 void os_setup_signal_handling(void)
  57 {
  58     struct sigaction act;
  59
  60     memset(&act, 0, sizeof(act));
  61     act.sa_handler = termsig_handler;
  62     sigaction(SIGINT,  &act, NULL);
  63     sigaction(SIGHUP,  &act, NULL);
  64     sigaction(SIGTERM, &act, NULL);
  65
  66     act.sa_handler = sigchld_handler;
  67     act.sa_flags = SA_NOCLDSTOP;
  68     sigaction(SIGCHLD, &act, NULL);
  69 }
  70
  71 /* Find a likely location for support files using the location of the binary.
  72    For installed binaries this will be "$bindir/../share/qemu".  When
  73    running from the build tree this will be "$bindir/../pc-bios".  */
  74 #define SHARE_SUFFIX "/share/qemu"
  75 #define BUILD_SUFFIX "/pc-bios"
  76 char *os_find_datadir(const char *argv0)
  77 {
  78     char *dir;
  79     char *p = NULL;
  80     char *res;
  81     char buf[PATH_MAX];
  82     size_t max_len;
  83
  84 #if defined(__linux__)
  85     {
  86         int len;
  87         len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
  88         if (len > 0) {
  89             buf[len] = 0;
  90             p = buf;
  91         }
  92     }
  93 #elif defined(__FreeBSD__)
  94     {
  95         static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
  96         size_t len = sizeof(buf) - 1;
  97
  98         *buf = '\0';
  99         if (!sysctl(mib, sizeof(mib)/sizeof(*mib), buf, &len, NULL, 0) &&
 100             *buf) {
 101             buf[sizeof(buf) - 1] = '\0';
 102             p = buf;
 103         }
 104     }
 105 #endif
 106     /* If we don't have any way of figuring out the actual executable
 107        location then try argv[0].  */
 108     if (!p) {
 109         p = realpath(argv0, buf);
 110         if (!p) {
 111             return NULL;
 112         }
 113     }
 114     dir = dirname(p);
 115     dir = dirname(dir);
 116
 117     max_len = strlen(dir) +
 118         MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1;
 119     res = qemu_mallocz(max_len);
 120     snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX);
 121     if (access(res, R_OK)) {
 122         snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX);
 123         if (access(res, R_OK)) {
 124             qemu_free(res);
 125             res = NULL;
 126         }
 127     }
 128
 129     return res;
 130 }
 131 #undef SHARE_SUFFIX
 132 #undef BUILD_SUFFIX