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v260
src/socket-activate/socket-activate.c
539 строк
18 KB
Daan De Meyer
tree-wide: Migrate to pidref_safe_fork()
02 янв 2026, 22:08
02 янв 2026, 22:08
52ecf37
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include <getopt.h> #include <sys/epoll.h> #include <sys/wait.h> #include <unistd.h> #include "sd-daemon.h" #include "alloc-util.h" #include "build.h" #include "daemon-util.h" #include "env-util.h" #include "errno-util.h" #include "escape.h" #include "fd-util.h" #include "format-util.h" #include "log.h" #include "main-func.h" #include "pidfd-util.h" #include "pidref.h" #include "pretty-print.h" #include "process-util.h" #include "socket-netlink.h" #include "socket-util.h" #include "string-util.h" #include "strv.h" static char **arg_listen = NULL; static bool arg_accept = false; static int arg_socket_type = SOCK_STREAM; static char **arg_setenv = NULL; static char **arg_fdnames = NULL; static bool arg_inetd = false; static bool arg_now = false; static int add_epoll(int epoll_fd, int fd) { struct epoll_event ev = { .events = EPOLLIN, .data.fd = fd, }; assert(epoll_fd >= 0); assert(fd >= 0); if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) return log_error_errno(errno, "Failed to add event on epoll fd:%d for fd:%d: %m", epoll_fd, fd); return 0; } static int open_sockets(int *ret_epoll_fd) { _cleanup_close_ int epoll_fd = -EBADF; int n, r, count = 0; assert(ret_epoll_fd); n = sd_listen_fds(true); if (n < 0) return log_error_errno(n, "Failed to read listening file descriptors from environment: %m"); if (n > 0) { log_info("Received %i descriptors via the environment.", n); for (int fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) { r = fd_cloexec(fd, arg_accept); if (r < 0) return r; count++; } } /* Close logging and all other descriptors */ if (arg_listen) { _cleanup_free_ int *except = new(int, n); if (!except) return log_oom(); for (int i = 0; i < n; i++) except[i] = SD_LISTEN_FDS_START + i; log_close(); log_set_open_when_needed(true); log_settle_target(); r = close_all_fds(except, n); if (r < 0) return log_error_errno(r, "Failed to close all file descriptors: %m"); } /* Note: we leak some fd's on error here. It doesn't matter much, since the program will exit * immediately anyway, but would be a pain to fix. */ STRV_FOREACH(address, arg_listen) { r = make_socket_fd(LOG_DEBUG, *address, arg_socket_type, (arg_accept * SOCK_CLOEXEC)); if (r < 0) return log_error_errno(r, "Failed to open '%s': %m", *address); assert(r == SD_LISTEN_FDS_START + count); count++; } if (arg_listen) { log_open(); log_set_open_when_needed(false); } if (count > 1 && !arg_accept && arg_inetd) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--inetd only supported with a single file descriptor, or with --accept."); if (arg_fdnames && !arg_inetd) { size_t n_fdnames = strv_length(arg_fdnames); if (!arg_accept && n_fdnames != (size_t) count) log_warning("The number of fd names is different from the number of fds: %zu vs %i", n_fdnames, count); if (arg_accept && n_fdnames > 1) log_warning("More than one fd name specified with --accept."); } if (!arg_now) { epoll_fd = epoll_create1(EPOLL_CLOEXEC); if (epoll_fd < 0) return log_error_errno(errno, "Failed to create epoll object: %m"); } for (int fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + count; fd++) { _cleanup_free_ char *name = NULL; getsockname_pretty(fd, &name); log_info("Listening on %s as %i.", strna(name), fd); if (epoll_fd >= 0) { r = add_epoll(epoll_fd, fd); if (r < 0) return r; } } *ret_epoll_fd = TAKE_FD(epoll_fd); return count; } static int exec_process(char * const *argv, int start_fd, size_t n_fds) { _cleanup_strv_free_ char **envp = NULL; int r; assert(!strv_isempty(argv)); assert(start_fd >= 0); assert(n_fds > 0); FOREACH_STRING(var, "TERM", "COLORTERM", "NO_COLOR", "PATH", "USER", "HOME") { const char *n; n = strv_find_prefix(environ, var); if (!n) continue; r = strv_extend(&envp, n); if (r < 0) return r; } if (arg_inetd) { assert(n_fds == 1); r = rearrange_stdio(start_fd, start_fd, STDERR_FILENO); /* invalidates start_fd on success + error */ if (r < 0) return log_error_errno(r, "Failed to move fd to stdin+stdout: %m"); } else { if (start_fd != SD_LISTEN_FDS_START) { assert(n_fds == 1); if (dup2(start_fd, SD_LISTEN_FDS_START) < 0) return log_error_errno(errno, "Failed to dup connection: %m"); safe_close(start_fd); } r = strv_extendf(&envp, "LISTEN_FDS=%zu", n_fds); if (r < 0) return r; r = strv_extendf(&envp, "LISTEN_PID=" PID_FMT, getpid_cached()); if (r < 0) return r; uint64_t pidfdid; if (pidfd_get_inode_id_self_cached(&pidfdid) >= 0) { r = strv_extendf(&envp, "LISTEN_PIDFDID=%" PRIu64, pidfdid); if (r < 0) return r; } if (arg_fdnames) { _cleanup_free_ char *names = NULL; size_t len; len = strv_length(arg_fdnames); if (len == 1) for (size_t i = 1; i < n_fds; i++) { r = strv_extend(&arg_fdnames, arg_fdnames[0]); if (r < 0) return log_oom(); } names = strv_join(arg_fdnames, ":"); if (!names) return log_oom(); char *t = strjoin("LISTEN_FDNAMES=", names); if (!t) return log_oom(); r = strv_consume(&envp, t); if (r < 0) return r; } } STRV_FOREACH(s, arg_setenv) { r = strv_env_replace_strdup(&envp, *s); if (r < 0) return r; } _cleanup_free_ char *joined = strv_join(argv, " "); if (!joined) return log_oom(); log_info("Executing: %s", joined); execvpe(argv[0], argv, envp); return log_error_errno(errno, "Failed to execute '%s': %m", joined); } static int fork_and_exec_process(char * const *argv, int fd) { _cleanup_free_ char *joined = NULL; int r; assert(!strv_isempty(argv)); assert(fd >= 0); joined = strv_join(argv, " "); if (!joined) return log_oom(); _cleanup_(pidref_done) PidRef child_pidref = PIDREF_NULL; r = pidref_safe_fork( "(activate)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGTERM|FORK_RLIMIT_NOFILE_SAFE|FORK_LOG, &child_pidref); if (r < 0) return r; if (r == 0) { /* In the child */ (void) exec_process(argv, fd, 1); _exit(EXIT_FAILURE); } log_info("Spawned '%s' as PID " PID_FMT ".", joined, child_pidref.pid); return 0; } static int do_accept(char * const *argv, int fd) { _cleanup_free_ char *local = NULL, *peer = NULL; _cleanup_close_ int fd_accepted = -EBADF; fd_accepted = accept4(fd, NULL, NULL, 0); if (fd_accepted < 0) { if (ERRNO_IS_ACCEPT_AGAIN(errno)) return 0; return log_error_errno(errno, "Failed to accept connection on fd:%d: %m", fd); } (void) getsockname_pretty(fd_accepted, &local); (void) getpeername_pretty(fd_accepted, true, &peer); log_info("Connection from %s to %s", strna(peer), strna(local)); return fork_and_exec_process(argv, fd_accepted); } /* SIGCHLD handler. */ static void sigchld_hdl(int sig) { int r; PROTECT_ERRNO; for (;;) { siginfo_t si = {}; r = waitid(P_ALL, 0, &si, WEXITED | WNOHANG); if (r < 0) { if (errno != ECHILD) log_error_errno(errno, "Failed to reap children: %m"); return; } if (si.si_pid == 0) return; log_info("Child %d died with code %d", si.si_pid, si.si_status); } } static int install_chld_handler(void) { static const struct sigaction act = { .sa_flags = SA_NOCLDSTOP | SA_RESTART, .sa_handler = sigchld_hdl, }; if (sigaction(SIGCHLD, &act, NULL) < 0) return log_error_errno(errno, "Failed to install SIGCHLD handler: %m"); return 0; } static int help(void) { _cleanup_free_ char *link = NULL; int r; r = terminal_urlify_man("systemd-socket-activate", "1", &link); if (r < 0) return log_oom(); printf("%s [OPTIONS...] COMMAND ...\n" "\n%sListen on sockets and launch child on connection.%s\n" "\nOptions:\n" " -h --help Show this help and exit\n" " --version Print version string and exit\n" " -l --listen=ADDR Listen for raw connections at ADDR\n" " -d --datagram Listen on datagram instead of stream socket\n" " --seqpacket Listen on SOCK_SEQPACKET instead of stream socket\n" " -a --accept Spawn separate child for each connection\n" " -E --setenv=NAME[=VALUE] Pass an environment variable to children\n" " --fdname=NAME[:NAME...] Specify names for file descriptors\n" " --inetd Enable inetd file descriptor passing protocol\n" " --now Start instantly instead of waiting for connection\n" "\nNote: file descriptors from sd_listen_fds() will be passed through.\n" "\nSee the %s for details.\n", program_invocation_short_name, ansi_highlight(), ansi_normal(), link); return 0; } static int parse_argv(int argc, char *argv[]) { enum { ARG_VERSION = 0x100, ARG_FDNAME, ARG_SEQPACKET, ARG_INETD, ARG_NOW, }; static const struct option options[] = { { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, ARG_VERSION }, { "datagram", no_argument, NULL, 'd' }, { "seqpacket", no_argument, NULL, ARG_SEQPACKET }, { "listen", required_argument, NULL, 'l' }, { "accept", no_argument, NULL, 'a' }, { "setenv", required_argument, NULL, 'E' }, { "environment", required_argument, NULL, 'E' }, /* legacy alias */ { "fdname", required_argument, NULL, ARG_FDNAME }, { "inetd", no_argument, NULL, ARG_INETD }, { "now", no_argument, NULL, ARG_NOW }, {} }; int c, r; assert(argc >= 0); assert(argv); /* Resetting to 0 forces the invocation of an internal initialization routine of getopt_long() * that checks for GNU extensions in optstring ('-' or '+' at the beginning). */ optind = 0; while ((c = getopt_long(argc, argv, "+hl:aE:d", options, NULL)) >= 0) switch (c) { case 'h': return help(); case ARG_VERSION: return version(); case 'l': r = strv_extend(&arg_listen, optarg); if (r < 0) return log_oom(); break; case 'd': if (arg_socket_type == SOCK_SEQPACKET) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--datagram may not be combined with --seqpacket."); arg_socket_type = SOCK_DGRAM; break; case ARG_SEQPACKET: if (arg_socket_type == SOCK_DGRAM) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--seqpacket may not be combined with --datagram."); arg_socket_type = SOCK_SEQPACKET; break; case 'a': arg_accept = true; break; case 'E': r = strv_env_replace_strdup_passthrough(&arg_setenv, optarg); if (r < 0) return log_error_errno(r, "Cannot assign environment variable %s: %m", optarg); break; case ARG_FDNAME: { _cleanup_strv_free_ char **names = NULL; names = strv_split(optarg, ":"); if (!names) return log_oom(); STRV_FOREACH(s, names) if (!fdname_is_valid(*s)) { _cleanup_free_ char *esc = NULL; esc = cescape(*s); log_warning("File descriptor name \"%s\" is not valid.", esc); } /* Empty optargs means one empty name */ r = strv_extend_strv(&arg_fdnames, strv_isempty(names) ? STRV_MAKE("") : names, false); if (r < 0) return log_error_errno(r, "strv_extend_strv: %m"); break; } case ARG_INETD: arg_inetd = true; break; case ARG_NOW: arg_now = true; break; case '?': return -EINVAL; default: assert_not_reached(); } if (optind == argc) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "%s: command to execute is missing.", program_invocation_short_name); if (arg_socket_type == SOCK_DGRAM && arg_accept) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Datagram sockets do not accept connections. " "The --datagram and --accept options may not be combined."); if (arg_accept && arg_now) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--now cannot be used in conjunction with --accept."); if (arg_fdnames && arg_inetd) log_warning("--fdname= has no effect with --inetd present."); return 1 /* work to do */; } static int run(int argc, char **argv) { _cleanup_close_ int epoll_fd = -EBADF; _cleanup_strv_free_ char **exec_argv = NULL; int r, n; log_setup(); r = parse_argv(argc, argv); if (r <= 0) return r; exec_argv = strv_copy(argv + optind); if (!exec_argv) return log_oom(); assert(!strv_isempty(exec_argv)); n = open_sockets(&epoll_fd); if (n < 0) return n; if (n == 0) return log_error_errno(SYNTHETIC_ERRNO(ENOENT), "No sockets to listen on specified or passed in."); if (arg_accept) { r = install_chld_handler(); if (r < 0) return r; } /* Notify the caller that all sockets are open now. */ _unused_ _cleanup_(notify_on_cleanup) const char *notify = notify_start(NOTIFY_READY_MESSAGE, NOTIFY_STOPPING_MESSAGE); for (;;) { struct epoll_event event; if (epoll_fd >= 0) { if (epoll_wait(epoll_fd, &event, 1, -1) < 0) { if (errno == EINTR) continue; return log_error_errno(errno, "epoll_wait() failed: %m"); } log_info("Communication attempt on fd %i.", event.data.fd); } if (!arg_accept) return exec_process(exec_argv, SD_LISTEN_FDS_START, (size_t) n); r = do_accept(exec_argv, event.data.fd); if (r < 0) return r; } } DEFINE_MAIN_FUNCTION(run);