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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
commit | b750101eb236130cf056c675997decbac904cc49 (patch) | |
tree | a5df1a06754bdd014cb975c051c83b01c9a97532 /src/activate | |
parent | Initial commit. (diff) | |
download | systemd-b750101eb236130cf056c675997decbac904cc49.tar.xz systemd-b750101eb236130cf056c675997decbac904cc49.zip |
Adding upstream version 252.22.upstream/252.22upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/activate')
-rw-r--r-- | src/activate/activate.c | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/src/activate/activate.c b/src/activate/activate.c new file mode 100644 index 0000000..0a16a43 --- /dev/null +++ b/src/activate/activate.c @@ -0,0 +1,488 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <getopt.h> +#include <sys/epoll.h> +#include <sys/prctl.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "sd-daemon.h" + +#include "alloc-util.h" +#include "env-util.h" +#include "errno-util.h" +#include "escape.h" +#include "fd-util.h" +#include "log.h" +#include "macro.h" +#include "pretty-print.h" +#include "process-util.h" +#include "signal-util.h" +#include "socket-netlink.h" +#include "socket-util.h" +#include "string-util.h" +#include "strv.h" +#include "terminal-util.h" +#include "util.h" + +static char **arg_listen = NULL; +static bool arg_accept = false; +static int arg_socket_type = SOCK_STREAM; +static char **arg_args = NULL; +static char **arg_setenv = NULL; +static char **arg_fdnames = NULL; +static bool arg_inetd = 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 *epoll_fd, bool accept) { + int n, r, count = 0; + + 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. I 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); + } + + *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); + + r = add_epoll(*epoll_fd, fd); + if (r < 0) + return r; + } + + return count; +} + +static int exec_process(const char *name, char **argv, int start_fd, size_t n_fds) { + _cleanup_strv_free_ char **envp = NULL; + int r; + + if (arg_inetd && n_fds != 1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "--inetd only supported for single file descriptors."); + + FOREACH_STRING(var, "TERM", "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; + + 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(); + } + else if (len != n_fds) + log_warning("The number of fd names is different than number of fds: %zu vs %zu", len, n_fds); + + 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("Execing %s (%s)", name, joined); + execvpe(name, argv, envp); + + return log_error_errno(errno, "Failed to execp %s (%s): %m", name, joined); +} + +static int fork_and_exec_process(const char *child, char **argv, int fd) { + _cleanup_free_ char *joined = NULL; + pid_t child_pid; + int r; + + joined = strv_join(argv, " "); + if (!joined) + return log_oom(); + + r = safe_fork("(activate)", + FORK_RESET_SIGNALS | FORK_DEATHSIG | FORK_RLIMIT_NOFILE_SAFE | FORK_LOG, + &child_pid); + if (r < 0) + return r; + if (r == 0) { + /* In the child */ + exec_process(child, argv, fd, 1); + _exit(EXIT_FAILURE); + } + + log_info("Spawned %s (%s) as PID " PID_FMT ".", child, joined, child_pid); + return 0; +} + +static int do_accept(const char *name, char **argv, int fd) { + _cleanup_free_ char *local = NULL, *peer = NULL; + _cleanup_close_ int fd_accepted = -1; + + 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(name, argv, fd_accepted); +} + +/* SIGCHLD handler. */ +static void sigchld_hdl(int sig) { + PROTECT_ERRNO; + + for (;;) { + siginfo_t si; + int r; + + si.si_pid = 0; + 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, 0) < 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...]\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" + "\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, + }; + + 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 }, + {} + }; + + 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 '?': + 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."); + + arg_args = argv + optind; + + return 1 /* work to do */; +} + +int main(int argc, char **argv) { + int r, n; + int epoll_fd = -1; + + log_show_color(true); + log_parse_environment(); + log_open(); + + r = parse_argv(argc, argv); + if (r <= 0) + return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE; + + r = install_chld_handler(); + if (r < 0) + return EXIT_FAILURE; + + n = open_sockets(&epoll_fd, arg_accept); + if (n < 0) + return EXIT_FAILURE; + if (n == 0) { + log_error("No sockets to listen on specified or passed in."); + return EXIT_FAILURE; + } + + for (;;) { + struct epoll_event event; + + if (epoll_wait(epoll_fd, &event, 1, -1) < 0) { + if (errno == EINTR) + continue; + + log_error_errno(errno, "epoll_wait() failed: %m"); + return EXIT_FAILURE; + } + + log_info("Communication attempt on fd %i.", event.data.fd); + if (arg_accept) { + r = do_accept(argv[optind], argv + optind, event.data.fd); + if (r < 0) + return EXIT_FAILURE; + } else + break; + } + + exec_process(argv[optind], argv + optind, SD_LISTEN_FDS_START, (size_t) n); + + return EXIT_SUCCESS; +} |