1217d6ca2b
The dangling remainder of the -tdf option revealed a deficiency in our option parsing: Options that have been declared, but are not supported in the switch-case statement in vl.c and not handled in the OS-specifc os_parse_cmd_args() functions are currently silently ignored. We should rather tell the users that they specified something that we can not handle, so let's print an error message and exit instead. Reported-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <1525453270-23074-3-git-send-email-thuth@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
395 lines
9.6 KiB
C
395 lines
9.6 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 "qemu/osdep.h"
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#include <sys/wait.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 "sysemu/sysemu.h"
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#include "net/slirp.h"
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#include "qemu-options.h"
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#include "qemu/error-report.h"
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#include "qemu/log.h"
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#include "qemu/cutils.h"
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#ifdef CONFIG_LINUX
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#include <sys/prctl.h>
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#endif
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/*
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* Must set all three of these at once.
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* Legal combinations are unset by name by uid
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*/
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static struct passwd *user_pwd; /* NULL non-NULL NULL */
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static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
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static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
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static const char *chroot_dir;
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static int daemonize;
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static int daemon_pipe;
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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(void)
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{
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char *dir, *exec_dir;
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char *res;
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size_t max_len;
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exec_dir = qemu_get_exec_dir();
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if (exec_dir == NULL) {
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return NULL;
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}
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dir = g_path_get_dirname(exec_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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g_free(dir);
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g_free(exec_dir);
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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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pstrcpy(name, sizeof(name), s);
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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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error_report("unable to change process name: %s", strerror(errno));
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exit(1);
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}
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#else
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error_report("Change of process name not supported by your OS");
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exit(1);
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#endif
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}
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static bool os_parse_runas_uid_gid(const char *optarg)
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{
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unsigned long lv;
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const char *ep;
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uid_t got_uid;
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gid_t got_gid;
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int rc;
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rc = qemu_strtoul(optarg, &ep, 0, &lv);
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got_uid = lv; /* overflow here is ID in C99 */
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if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
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return false;
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}
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rc = qemu_strtoul(ep + 1, 0, 0, &lv);
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got_gid = lv; /* overflow here is ID in C99 */
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if (rc || got_gid != lv || got_gid == (gid_t)-1) {
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return false;
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}
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user_pwd = NULL;
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user_uid = got_uid;
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user_gid = got_gid;
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return true;
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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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int 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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error_report("The -smb option is deprecated. "
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"Please use '-netdev user,smb=...' instead.");
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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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user_uid = -1;
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user_gid = -1;
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} else if (!os_parse_runas_uid_gid(optarg)) {
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error_report("User \"%s\" doesn't exist"
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" (and is not <uid>:<gid>)",
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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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#if defined(CONFIG_LINUX)
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case QEMU_OPTION_enablefips:
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fips_set_state(true);
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break;
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#endif
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default:
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return -1;
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}
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return 0;
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}
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static void change_process_uid(void)
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{
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assert((user_uid == (uid_t)-1) || user_pwd == NULL);
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assert((user_uid == (uid_t)-1) ==
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(user_gid == (gid_t)-1));
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if (user_pwd || user_uid != (uid_t)-1) {
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gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
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uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
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if (setgid(intended_gid) < 0) {
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error_report("Failed to setgid(%d)", intended_gid);
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exit(1);
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}
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if (user_pwd) {
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if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
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error_report("Failed to initgroups(\"%s\", %d)",
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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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} else {
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if (setgroups(1, &user_gid) < 0) {
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error_report("Failed to setgroups(1, [%d])",
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user_gid);
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exit(1);
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}
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}
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if (setuid(intended_uid) < 0) {
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error_report("Failed to setuid(%d)", intended_uid);
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exit(1);
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}
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if (setuid(0) != -1) {
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error_report("Dropping privileges failed");
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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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error_report("chroot failed");
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exit(1);
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}
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if (chdir("/")) {
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error_report("not able to chdir to /: %s", strerror(errno));
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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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int fds[2];
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if (pipe(fds) == -1) {
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exit(1);
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}
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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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do {
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len = read(fds[0], &status, 1);
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} while (len < 0 && errno == EINTR);
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/* only exit successfully if our child actually wrote
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* a one-byte zero to our pipe, upon successful init */
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exit(len == 1 && status == 0 ? 0 : 1);
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} else if (pid < 0) {
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exit(1);
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}
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close(fds[0]);
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daemon_pipe = fds[1];
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qemu_set_cloexec(daemon_pipe);
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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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}
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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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if (chdir("/")) {
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error_report("not able to chdir to /: %s", strerror(errno));
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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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}
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change_root();
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change_process_uid();
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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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dup2(fd, 0);
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dup2(fd, 1);
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/* In case -D is given do not redirect stderr to /dev/null */
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if (!qemu_logfile) {
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dup2(fd, 2);
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}
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close(fd);
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do {
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len = write(daemon_pipe, &status, 1);
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} while (len < 0 && errno == EINTR);
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if (len != 1) {
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exit(1);
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}
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}
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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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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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/* keep pidfile open & locked forever */
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return 0;
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}
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bool is_daemonized(void)
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{
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return daemonize;
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}
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int os_mlock(void)
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{
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int ret = 0;
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ret = mlockall(MCL_CURRENT | MCL_FUTURE);
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if (ret < 0) {
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error_report("mlockall: %s", strerror(errno));
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}
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return ret;
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}
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