/* * os-posix.c * * Copyright (c) 2003-2008 Fabrice Bellard * Copyright (c) 2010 Red Hat, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include <sys/wait.h> /*needed for MAP_POPULATE before including qemu-options.h */ #include <pwd.h> #include <grp.h> #include <libgen.h> /* Needed early for CONFIG_BSD etc. */ #include "sysemu/sysemu.h" #include "net/slirp.h" #include "qemu-options.h" #include "qemu/rcu.h" #include "qemu/error-report.h" #include "qemu/log.h" #include "qemu/cutils.h" #ifdef CONFIG_LINUX #include <sys/prctl.h> #endif static struct passwd *user_pwd; static const char *chroot_dir; static int daemonize; static int daemon_pipe; void os_setup_early_signal_handling(void) { struct sigaction act; sigfillset(&act.sa_mask); act.sa_flags = 0; act.sa_handler = SIG_IGN; sigaction(SIGPIPE, &act, NULL); } static void termsig_handler(int signal, siginfo_t *info, void *c) { qemu_system_killed(info->si_signo, info->si_pid); } void os_setup_signal_handling(void) { struct sigaction act; memset(&act, 0, sizeof(act)); act.sa_sigaction = termsig_handler; act.sa_flags = SA_SIGINFO; sigaction(SIGINT, &act, NULL); sigaction(SIGHUP, &act, NULL); sigaction(SIGTERM, &act, NULL); } /* Find a likely location for support files using the location of the binary. For installed binaries this will be "$bindir/../share/qemu". When running from the build tree this will be "$bindir/../pc-bios". */ #define SHARE_SUFFIX "/share/qemu" #define BUILD_SUFFIX "/pc-bios" char *os_find_datadir(void) { char *dir, *exec_dir; char *res; size_t max_len; exec_dir = qemu_get_exec_dir(); if (exec_dir == NULL) { return NULL; } dir = dirname(exec_dir); max_len = strlen(dir) + MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1; res = g_malloc0(max_len); snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX); if (access(res, R_OK)) { snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX); if (access(res, R_OK)) { g_free(res); res = NULL; } } g_free(exec_dir); return res; } #undef SHARE_SUFFIX #undef BUILD_SUFFIX void os_set_proc_name(const char *s) { #if defined(PR_SET_NAME) char name[16]; if (!s) return; pstrcpy(name, sizeof(name), s); /* Could rewrite argv[0] too, but that's a bit more complicated. This simple way is enough for `top'. */ if (prctl(PR_SET_NAME, name)) { perror("unable to change process name"); exit(1); } #else fprintf(stderr, "Change of process name not supported by your OS\n"); exit(1); #endif } /* * Parse OS specific command line options. * return 0 if option handled, -1 otherwise */ void os_parse_cmd_args(int index, const char *optarg) { switch (index) { #ifdef CONFIG_SLIRP case QEMU_OPTION_smb: error_report("The -smb option is deprecated. " "Please use '-netdev user,smb=...' instead."); if (net_slirp_smb(optarg) < 0) exit(1); break; #endif case QEMU_OPTION_runas: user_pwd = getpwnam(optarg); if (!user_pwd) { fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); exit(1); } break; case QEMU_OPTION_chroot: chroot_dir = optarg; break; case QEMU_OPTION_daemonize: daemonize = 1; break; #if defined(CONFIG_LINUX) case QEMU_OPTION_enablefips: fips_set_state(true); break; #endif } } static void change_process_uid(void) { if (user_pwd) { if (setgid(user_pwd->pw_gid) < 0) { fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); exit(1); } if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n", user_pwd->pw_name, user_pwd->pw_gid); exit(1); } if (setuid(user_pwd->pw_uid) < 0) { fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); exit(1); } if (setuid(0) != -1) { fprintf(stderr, "Dropping privileges failed\n"); exit(1); } } } static void change_root(void) { if (chroot_dir) { if (chroot(chroot_dir) < 0) { fprintf(stderr, "chroot failed\n"); exit(1); } if (chdir("/")) { perror("not able to chdir to /"); exit(1); } } } void os_daemonize(void) { if (daemonize) { pid_t pid; int fds[2]; if (pipe(fds) == -1) { exit(1); } pid = fork(); if (pid > 0) { uint8_t status; ssize_t len; close(fds[1]); do { len = read(fds[0], &status, 1); } while (len < 0 && errno == EINTR); /* only exit successfully if our child actually wrote * a one-byte zero to our pipe, upon successful init */ exit(len == 1 && status == 0 ? 0 : 1); } else if (pid < 0) { exit(1); } close(fds[0]); daemon_pipe = fds[1]; qemu_set_cloexec(daemon_pipe); setsid(); pid = fork(); if (pid > 0) { exit(0); } else if (pid < 0) { exit(1); } umask(027); signal(SIGTSTP, SIG_IGN); signal(SIGTTOU, SIG_IGN); signal(SIGTTIN, SIG_IGN); rcu_after_fork(); } } void os_setup_post(void) { int fd = 0; if (daemonize) { if (chdir("/")) { perror("not able to chdir to /"); exit(1); } TFR(fd = qemu_open("/dev/null", O_RDWR)); if (fd == -1) { exit(1); } } change_root(); change_process_uid(); if (daemonize) { uint8_t status = 0; ssize_t len; dup2(fd, 0); dup2(fd, 1); /* In case -D is given do not redirect stderr to /dev/null */ if (!qemu_logfile) { dup2(fd, 2); } close(fd); do { len = write(daemon_pipe, &status, 1); } while (len < 0 && errno == EINTR); if (len != 1) { exit(1); } } } void os_set_line_buffering(void) { setvbuf(stdout, NULL, _IOLBF, 0); } int qemu_create_pidfile(const char *filename) { char buffer[128]; int len; int fd; fd = qemu_open(filename, O_RDWR | O_CREAT, 0600); if (fd == -1) { return -1; } if (lockf(fd, F_TLOCK, 0) == -1) { close(fd); return -1; } len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid()); if (write(fd, buffer, len) != len) { close(fd); return -1; } /* keep pidfile open & locked forever */ return 0; } bool is_daemonized(void) { return daemonize; } int os_mlock(void) { int ret = 0; ret = mlockall(MCL_CURRENT | MCL_FUTURE); if (ret < 0) { perror("mlockall"); } return ret; }