1bbd1592c8
Spotted by Coverity. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
396 lines
8.8 KiB
C
396 lines
8.8 KiB
C
/*
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* os-posix.c
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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* Copyright (c) 2010 Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <unistd.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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/*needed for MAP_POPULATE before including qemu-options.h */
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#include <sys/mman.h>
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#include <pwd.h>
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#include <grp.h>
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#include <libgen.h>
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/* Needed early for CONFIG_BSD etc. */
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#include "config-host.h"
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#include "sysemu.h"
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#include "net/slirp.h"
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#include "qemu-options.h"
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#ifdef CONFIG_LINUX
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#include <sys/prctl.h>
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#include <sys/syscall.h>
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#endif
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#ifdef CONFIG_EVENTFD
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#include <sys/eventfd.h>
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#endif
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static struct passwd *user_pwd;
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static const char *chroot_dir;
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static int daemonize;
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static int fds[2];
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void os_setup_early_signal_handling(void)
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{
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struct sigaction act;
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sigfillset(&act.sa_mask);
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act.sa_flags = 0;
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act.sa_handler = SIG_IGN;
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sigaction(SIGPIPE, &act, NULL);
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}
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static void termsig_handler(int signal, siginfo_t *info, void *c)
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{
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qemu_system_killed(info->si_signo, info->si_pid);
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}
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void os_setup_signal_handling(void)
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{
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struct sigaction act;
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memset(&act, 0, sizeof(act));
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act.sa_sigaction = termsig_handler;
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act.sa_flags = SA_SIGINFO;
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sigaction(SIGINT, &act, NULL);
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sigaction(SIGHUP, &act, NULL);
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sigaction(SIGTERM, &act, NULL);
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}
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/* Find a likely location for support files using the location of the binary.
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For installed binaries this will be "$bindir/../share/qemu". When
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running from the build tree this will be "$bindir/../pc-bios". */
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#define SHARE_SUFFIX "/share/qemu"
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#define BUILD_SUFFIX "/pc-bios"
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char *os_find_datadir(const char *argv0)
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{
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char *dir;
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char *p = NULL;
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char *res;
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char buf[PATH_MAX];
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size_t max_len;
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#if defined(__linux__)
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{
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int len;
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len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
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if (len > 0) {
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buf[len] = 0;
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p = buf;
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}
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}
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#elif defined(__FreeBSD__)
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{
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static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
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size_t len = sizeof(buf) - 1;
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*buf = '\0';
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if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
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*buf) {
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buf[sizeof(buf) - 1] = '\0';
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p = buf;
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}
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}
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#endif
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/* If we don't have any way of figuring out the actual executable
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location then try argv[0]. */
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if (!p) {
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p = realpath(argv0, buf);
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if (!p) {
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return NULL;
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}
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}
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dir = dirname(p);
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dir = dirname(dir);
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max_len = strlen(dir) +
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MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1;
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res = g_malloc0(max_len);
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snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX);
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if (access(res, R_OK)) {
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snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX);
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if (access(res, R_OK)) {
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g_free(res);
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res = NULL;
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}
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}
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return res;
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}
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#undef SHARE_SUFFIX
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#undef BUILD_SUFFIX
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void os_set_proc_name(const char *s)
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{
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#if defined(PR_SET_NAME)
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char name[16];
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if (!s)
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return;
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name[sizeof(name) - 1] = 0;
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strncpy(name, s, sizeof(name));
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/* Could rewrite argv[0] too, but that's a bit more complicated.
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This simple way is enough for `top'. */
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if (prctl(PR_SET_NAME, name)) {
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perror("unable to change process name");
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exit(1);
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}
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#else
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fprintf(stderr, "Change of process name not supported by your OS\n");
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exit(1);
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#endif
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}
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/*
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* Parse OS specific command line options.
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* return 0 if option handled, -1 otherwise
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*/
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void os_parse_cmd_args(int index, const char *optarg)
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{
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switch (index) {
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#ifdef CONFIG_SLIRP
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case QEMU_OPTION_smb:
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if (net_slirp_smb(optarg) < 0)
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exit(1);
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break;
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#endif
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case QEMU_OPTION_runas:
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user_pwd = getpwnam(optarg);
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if (!user_pwd) {
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fprintf(stderr, "User \"%s\" doesn't exist\n", optarg);
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exit(1);
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}
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break;
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case QEMU_OPTION_chroot:
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chroot_dir = optarg;
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break;
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case QEMU_OPTION_daemonize:
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daemonize = 1;
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break;
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}
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return;
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}
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static void change_process_uid(void)
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{
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if (user_pwd) {
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if (setgid(user_pwd->pw_gid) < 0) {
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fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);
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exit(1);
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}
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if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
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fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n",
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user_pwd->pw_name, user_pwd->pw_gid);
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exit(1);
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}
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if (setuid(user_pwd->pw_uid) < 0) {
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fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);
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exit(1);
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}
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if (setuid(0) != -1) {
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fprintf(stderr, "Dropping privileges failed\n");
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exit(1);
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}
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}
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}
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static void change_root(void)
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{
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if (chroot_dir) {
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if (chroot(chroot_dir) < 0) {
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fprintf(stderr, "chroot failed\n");
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exit(1);
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}
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if (chdir("/")) {
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perror("not able to chdir to /");
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exit(1);
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}
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}
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}
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void os_daemonize(void)
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{
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if (daemonize) {
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pid_t pid;
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if (pipe(fds) == -1)
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exit(1);
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pid = fork();
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if (pid > 0) {
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uint8_t status;
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ssize_t len;
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close(fds[1]);
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again:
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len = read(fds[0], &status, 1);
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if (len == -1 && (errno == EINTR))
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goto again;
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if (len != 1)
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exit(1);
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else if (status == 1) {
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fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno));
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exit(1);
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} else
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exit(0);
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} else if (pid < 0)
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exit(1);
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close(fds[0]);
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qemu_set_cloexec(fds[1]);
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setsid();
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pid = fork();
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if (pid > 0)
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exit(0);
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else if (pid < 0)
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exit(1);
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umask(027);
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signal(SIGTSTP, SIG_IGN);
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signal(SIGTTOU, SIG_IGN);
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signal(SIGTTIN, SIG_IGN);
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}
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}
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void os_setup_post(void)
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{
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int fd = 0;
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if (daemonize) {
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uint8_t status = 0;
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ssize_t len;
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again1:
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len = write(fds[1], &status, 1);
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if (len == -1 && (errno == EINTR))
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goto again1;
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if (len != 1)
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exit(1);
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if (chdir("/")) {
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perror("not able to chdir to /");
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exit(1);
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}
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TFR(fd = qemu_open("/dev/null", O_RDWR));
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if (fd == -1)
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exit(1);
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}
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change_root();
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change_process_uid();
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if (daemonize) {
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dup2(fd, 0);
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dup2(fd, 1);
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dup2(fd, 2);
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close(fd);
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}
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}
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void os_pidfile_error(void)
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{
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if (daemonize) {
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uint8_t status = 1;
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if (write(fds[1], &status, 1) != 1) {
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perror("daemonize. Writing to pipe\n");
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}
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} else
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fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));
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}
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void os_set_line_buffering(void)
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{
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setvbuf(stdout, NULL, _IOLBF, 0);
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}
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/*
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* Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set.
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*/
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int qemu_eventfd(int fds[2])
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{
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#ifdef CONFIG_EVENTFD
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int ret;
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ret = eventfd(0, 0);
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if (ret >= 0) {
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fds[0] = ret;
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qemu_set_cloexec(ret);
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if ((fds[1] = dup(ret)) == -1) {
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close(ret);
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return -1;
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}
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qemu_set_cloexec(fds[1]);
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return 0;
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}
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if (errno != ENOSYS) {
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return -1;
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}
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#endif
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return qemu_pipe(fds);
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}
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int qemu_create_pidfile(const char *filename)
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{
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char buffer[128];
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int len;
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int fd;
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fd = qemu_open(filename, O_RDWR | O_CREAT, 0600);
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if (fd == -1) {
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return -1;
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}
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if (lockf(fd, F_TLOCK, 0) == -1) {
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close(fd);
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return -1;
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}
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len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid());
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if (write(fd, buffer, len) != len) {
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close(fd);
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return -1;
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}
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close(fd);
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return 0;
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}
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int qemu_get_thread_id(void)
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{
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#if defined (__linux__)
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return syscall(SYS_gettid);
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#else
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return getpid();
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#endif
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}
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