/** * Copyright © 2015, 2016 Mattias Andrée * * 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 "daemon.h" #include "daemonise.h" #include #include #include #include #include #include #include #include /** * The size of the backlog on the socket. */ #ifndef SATD_BACKLOG # define SATD_BACKLOG 5 #endif #if SATD_BACKLOG > SOMAXCONN # undef SATD_BACKLOG # defined SATD_BACKLOG SOMAXCONN #endif #define close(fd) (fd < 0 ? 0 : close(fd)) COMMAND("satd") USAGE("[-f]") /** * Create the socket. * * @param address Output parameter for the socket address. * @return The file descriptor for the socket, -1 on error. */ static int create_socket(struct sockaddr_un *address) { const void *_cvoid; const char *dir; int fd = -1, saved_errno; /* Get socket address. */ dir = getenv("XDG_RUNTIME_DIR"), dir = (dir ? dir : "/run"); if (strlen(dir) + sizeof("/" PACKAGE "/socket") > sizeof(address->sun_path)) t ((errno = ENAMETOOLONG)); stpcpy(stpcpy(address->sun_path, dir), "/" PACKAGE "/socket"); address->sun_family = AF_UNIX; /* Create socket. */ unlink(address->sun_path); t ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1); t (fchmod(fd, S_IRWXU)); t (bind(fd, (const struct sockaddr *)(_cvoid = address), (socklen_t)sizeof(*address))); /* EADDRINUSE just means that the file already exists, not that it is actually used. */ return fd; fail: saved_errno = errno, close(fd), errno = saved_errno; return -1; } /** * Create the state file. * * @param state_path Output parameter for the state file's pathname. * @return A file descriptor to the state file, -1 on error. */ static int create_state(char **state_path) { const char *dir; char *path; int fd = -1, saved_errno; /* Create directory. */ dir = getenv("XDG_RUNTIME_DIR"), dir = (dir ? dir : "/run"); t (!(path = malloc(strlen(dir) * sizeof(char) + sizeof("/" PACKAGE "/state")))); stpcpy(stpcpy(path, dir), "/" PACKAGE "/state"); t (fd = open(path, O_RDWR | O_CREAT /* but not O_EXCL or O_TRUNC */, S_IRUSR | S_IWUSR), fd == -1); *state_path = path, path = NULL; fail: saved_errno = errno, free(path), errno = saved_errno; return fd; } /** * Create and lock the lock file, and its directory. * * @return A file descriptor to the lock file, -1 on error. */ static int create_lock(void) { const char *dir; char *path; char *p; int fd = -1, saved_errno = 0; /* Create directory. */ dir = getenv("XDG_RUNTIME_DIR"), dir = (dir ? dir : "/run"); t (!(path = malloc(strlen(dir) * sizeof(char) + sizeof("/" PACKAGE "/lock")))); p = stpcpy(stpcpy(path, dir), "/" PACKAGE); t (mkdir(path, S_IRWXU) && (errno != EEXIST)); /* Open file. */ stpcpy(p, "/lock"); t (fd = open(path, O_RDWR | O_CREAT /* but not O_EXCL or O_TRUNC */, S_IRUSR | S_IWUSR), fd == -1); /* Check that the daemon is not running, and mark it as running. */ if (flock(fd, LOCK_EX | LOCK_NB)) { t (errno != EWOULDBLOCK); fprintf(stderr, "%s: the daemon is already in reading.\n", argv0); errno = 0; goto fail; } goto done; fail: saved_errno = errno, close(fd); done: free(path), errno = saved_errno; return fd; } /** * Construct the pathname for the hook script. * * @param env The environment variable to use for the beginning * of the pathname, `NULL` for the home directory. * @param suffix The rest of the pathname. * @return The pathname. * * @throws 0 The environment variable is not set, or, if `env` is * `NULL` the user is root or homeless. */ static char * hookpath(const char *env, const char *suffix) { struct passwd *pwd; const char *prefix = NULL; char *path; if (env) { prefix = getenv(env); } else if (getuid()) { pwd = getpwuid(getuid()); prefix = pwd ? pwd->pw_dir : NULL; } if (!prefix || !*prefix) return errno = 0, NULL; t (!(path = malloc((strlen(prefix) + strlen(suffix) + 1) * sizeof(char)))); stpcpy(stpcpy(path, prefix), suffix); fail: return path; } /** * Duplicate a file descriptor, and * open /dev/null to the old file descriptor. * However, if `old` is 3 or greater, it will * be closed rather than /dev/null. * * @param old The old file descriptor. * @param new The new file descriptor. * @return `new`, -1 on error. */ static int dup2_and_null(int old, int new) { int fd = -1, saved_errno; if (old == new) return new; t (DUP2_AND_CLOSE(old, new)); if (old >= 3) return new; t (fd = open("/dev/null", O_RDWR), fd == -1); if (fd == old) return new; t (DUP2_AND_CLOSE(fd, old)); return new; fail: saved_errno = errno, close(fd), errno = saved_errno; return -1; } /** * The sat daemon initialisation. * * @param argc Any value in [0, 2] is accepted. * @param argv The name of the process, and -f if the process * shall not be daemonised. * @return 0 The process was successful. * @return 1 The process failed queuing the job. * @return 2 User error, you do not know what you are doing. */ int main(int argc, char *argv[]) { #define GET_FD(FD, WANT, CALL) \ t (FD = CALL, FD == -1); \ t (dup2_and_null(FD, WANT) == -1); \ FD = WANT #define HOOKPATH(PRE, SUF) \ t (path = path ? path : hookpath(PRE, SUF), !path && errno) struct sockaddr_un address; int sock = -1, state = -1, boot = -1, real = -1, lock = -1, foreground = 0; char *path = NULL; struct itimerspec spec; /* Parse command line. */ if (argc > 0) argv0 = argv[0]; if (argc > 2) usage(); if ((argc == 2) && (!(foreground = !strcmp(argv[1], "-f")))) usage(); /* Get hook-script pathname. */ if (!getenv("SAT_HOOK_PATH")) { HOOKPATH("XDG_CONFIG_HOME", "/sat/hook"); HOOKPATH("HOME", "/.config/sat/hook"); HOOKPATH(NULL, "/.config/sat/hook"); t (setenv("SAT_HOOK_PATH", path ? path : "/etc/sat/hook", 1)); free(path), path = NULL; } /* Open/create lock file and state file, and create socket. */ GET_FD(lock, LOCK_FILENO, create_lock()); GET_FD(state, STATE_FILENO, create_state(&path)); GET_FD(sock, SOCK_FILENO, create_socket(&address)); /* Create timers. */ GET_FD(boot, BOOT_FILENO, timerfd_create(CLOCK_BOOTTIME, 0)); GET_FD(real, REAL_FILENO, timerfd_create(CLOCK_REALTIME, 0)); /* Configure timers. */ memset(&spec, 0, sizeof(spec)); t (timerfd_settime(boot, TFD_TIMER_ABSTIME, &spec, NULL)); t (timerfd_settime(real, TFD_TIMER_ABSTIME, &spec, NULL)); /* Listen for incoming conections. */ t (listen(sock, SATD_BACKLOG)); /* Daemonise. */ t (foreground ? 0 : daemonise("satd", DAEMONISE_KEEP_FDS | DAEMONISE_NEW_PID, 3, 4, 5, 6, 7, -1)); /* Change to a process image without all this initialisation text. */ execl(LIBEXECDIR "/" PACKAGE "/satd-diminished", argv0, address.sun_path, path, NULL); fail: if (errno) perror(argv0); free(path); if (sock >= 0) unlink(address.sun_path); close(sock), close(state), close(boot), close(real), close(lock); undaemonise(); return 1; }