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Diffstat (limited to 'src/activate/activate.c')
| -rw-r--r-- | src/activate/activate.c | 443 |
1 files changed, 443 insertions, 0 deletions
diff --git a/src/activate/activate.c b/src/activate/activate.c new file mode 100644 index 0000000000..87526d47cc --- /dev/null +++ b/src/activate/activate.c @@ -0,0 +1,443 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2013 Zbigniew Jędrzejewski-Szmek + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <unistd.h> +#include <fcntl.h> +#include <sys/epoll.h> +#include <sys/prctl.h> +#include <sys/socket.h> +#include <sys/wait.h> +#include <getopt.h> + +#include <systemd/sd-daemon.h> + +#include "socket-util.h" +#include "build.h" +#include "log.h" +#include "strv.h" +#include "macro.h" + +static char** arg_listen = NULL; +static bool arg_accept = false; +static char** arg_args = NULL; +static char** arg_environ = NULL; + +static int add_epoll(int epoll_fd, int fd) { + int r; + struct epoll_event ev = {EPOLLIN}; + ev.data.fd = fd; + + assert(epoll_fd >= 0); + assert(fd >= 0); + + r = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev); + if (r < 0) + log_error("Failed to add event on epoll fd:%d for fd:%d: %s", + epoll_fd, fd, strerror(-r)); + return r; +} + +static int set_nocloexec(int fd) { + int flags; + + flags = fcntl(fd, F_GETFD); + if (flags < 0) { + log_error("Querying flags for fd:%d: %m", fd); + return -errno; + } + + if (!(flags & FD_CLOEXEC)) + return 0; + + if (fcntl(fd, F_SETFD, flags & ~FD_CLOEXEC) < 0) { + log_error("Settings flags for fd:%d: %m", fd); + return -errno; + } + + return 0; +} + +static int print_socket(const char* desc, int fd) { + int r; + SocketAddress addr = { + .size = sizeof(union sockaddr_union), + .type = SOCK_STREAM, + }; + int family; + + r = getsockname(fd, &addr.sockaddr.sa, &addr.size); + if (r < 0) { + log_warning("Failed to query socket on fd:%d: %m", fd); + return 0; + } + + family = socket_address_family(&addr); + switch(family) { + case AF_INET: + case AF_INET6: { + char* _cleanup_free_ a = NULL; + r = socket_address_print(&addr, &a); + if (r < 0) + log_warning("socket_address_print(): %s", strerror(-r)); + else + log_info("%s %s address %s", + desc, + family == AF_INET ? "IP" : "IPv6", + a); + break; + } + default: + log_warning("Connection with unknown family %d", family); + } + + return 0; +} + +static int open_sockets(int *epoll_fd, bool accept) { + int n, fd; + int count = 0; + char **address; + + n = sd_listen_fds(true); + if (n < 0) { + log_error("Failed to read listening file descriptors from environment: %s", + strerror(-n)); + return n; + } + log_info("Received %d descriptors", n); + + for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) { + log_debug("Received descriptor fd:%d", fd); + print_socket("Listening on", fd); + + if (!arg_accept) { + int r = set_nocloexec(fd); + if (r < 0) + return r; + } + + count ++; + } + + /** 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) { + log_info("Opening address %s", *address); + + fd = make_socket_fd(*address, SOCK_STREAM | (arg_accept*SOCK_CLOEXEC)); + if (fd < 0) { + log_error("Failed to open '%s': %s", *address, strerror(-fd)); + return fd; + } + + count ++; + } + + *epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (*epoll_fd < 0) { + log_error("Failed to create epoll object: %m"); + return -errno; + } + + for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + count; fd++) { + int r = add_epoll(*epoll_fd, fd); + if (r < 0) + return r; + } + + return count; +} + +static int launch(char* name, char **argv, char **env, int fds) { + unsigned n_env = 0, length; + _cleanup_strv_free_ char **envp = NULL; + char **s; + static const char* tocopy[] = {"TERM=", "PATH=", "USER=", "HOME="}; + _cleanup_free_ char *tmp = NULL; + unsigned i; + + length = strv_length(arg_environ); + /* PATH, TERM, HOME, USER, LISTEN_FDS, LISTEN_PID, NULL */ + envp = new(char *, length + 7); + + STRV_FOREACH(s, arg_environ) { + if (strchr(*s, '=')) + envp[n_env++] = *s; + else { + _cleanup_free_ char *p = strappend(*s, "="); + if (!p) + return log_oom(); + envp[n_env] = strv_find_prefix(env, p); + if (envp[n_env]) + n_env ++; + } + } + + for (i = 0; i < ELEMENTSOF(tocopy); i++) { + envp[n_env] = strv_find_prefix(env, tocopy[i]); + if (envp[n_env]) + n_env ++; + } + + if ((asprintf((char**)(envp + n_env++), "LISTEN_FDS=%d", fds) < 0) || + (asprintf((char**)(envp + n_env++), "LISTEN_PID=%d", getpid()) < 0)) + return log_oom(); + + tmp = strv_join(argv, " "); + if (!tmp) + return log_oom(); + + log_info("Execing %s (%s)", name, tmp); + execvpe(name, argv, envp); + log_error("Failed to execp %s (%s): %m", name, tmp); + return -errno; +} + +static int launch1(const char* child, char** argv, char **env, int fd) { + pid_t parent_pid, child_pid; + int r; + + _cleanup_free_ char *tmp = NULL; + tmp = strv_join(argv, " "); + if (!tmp) + return log_oom(); + + parent_pid = getpid(); + + child_pid = fork(); + if (child_pid < 0) { + log_error("Failed to fork: %m"); + return -errno; + } + + /* In the child */ + if (child_pid == 0) { + r = dup2(fd, STDIN_FILENO); + if (r < 0) { + log_error("Failed to dup connection to stdin: %m"); + _exit(EXIT_FAILURE); + } + + r = dup2(fd, STDOUT_FILENO); + if (r < 0) { + log_error("Failed to dup connection to stdout: %m"); + _exit(EXIT_FAILURE); + } + + r = close(fd); + if (r < 0) { + log_error("Failed to close dupped connection: %m"); + _exit(EXIT_FAILURE); + } + + /* Make sure the child goes away when the parent dies */ + if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) + _exit(EXIT_FAILURE); + + /* Check whether our parent died before we were able + * to set the death signal */ + if (getppid() != parent_pid) + _exit(EXIT_SUCCESS); + + execvp(child, argv); + log_error("Failed to exec child %s: %m", child); + _exit(EXIT_FAILURE); + } + + log_info("Spawned %s (%s) as PID %d", child, tmp, child_pid); + + return 0; +} + +static int do_accept(const char* name, char **argv, char **envp, int fd) { + SocketAddress addr = { + .size = sizeof(union sockaddr_union), + .type = SOCK_STREAM, + }; + int fd2, r; + + fd2 = accept(fd, &addr.sockaddr.sa, &addr.size); + if (fd2 < 0) { + log_error("Failed to accept connection on fd:%d: %m", fd); + return fd2; + } + + print_socket("Connection from", fd2); + + r = launch1(name, argv, envp, fd2); + return r; +} + +/* SIGCHLD handler. */ +static void sigchld_hdl(int sig, siginfo_t *t, void *data) +{ + log_info("Child %d died with code %d", t->si_pid, t->si_status); + /* Wait for a dead child. */ + waitpid(t->si_pid, NULL, 0); +} + +static int install_chld_handler(void) { + int r; + struct sigaction act; + zero(act); + act.sa_flags = SA_SIGINFO; + act.sa_sigaction = sigchld_hdl; + + r = sigaction(SIGCHLD, &act, 0); + if (r < 0) + log_error("Failed to install SIGCHLD handler: %m"); + return r; +} + +static int help(void) { + printf("%s [OPTIONS...]\n\n" + "Listen on sockets and launch child on connection.\n\n" + "Options:\n" + " -l --listen=ADDR Listen for raw connections at ADDR\n" + " -a --accept Spawn separate child for each connection\n" + " -h --help Show this help and exit\n" + " --version Print version string and exit\n" + "\n" + "Note: file descriptors from sd_listen_fds() will be passed through.\n" + , program_invocation_short_name + ); + + return 0; +} + +static int parse_argv(int argc, char *argv[]) { + enum { + ARG_VERSION = 0x100, + }; + + static const struct option options[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "listen", required_argument, NULL, 'l' }, + { "accept", no_argument, NULL, 'a' }, + { "environment", required_argument, NULL, 'E' }, + { NULL, 0, NULL, 0 } + }; + + int c; + + assert(argc >= 0); + assert(argv); + + while ((c = getopt_long(argc, argv, "+hl:saE:", options, NULL)) >= 0) + switch(c) { + case 'h': + help(); + return 0 /* done */; + + case ARG_VERSION: + puts(PACKAGE_STRING); + puts(SYSTEMD_FEATURES); + return 0 /* done */; + + case 'l': { + int r = strv_extend(&arg_listen, optarg); + if (r < 0) + return r; + + break; + } + + case 'a': + arg_accept = true; + break; + + case 'E': { + int r = strv_extend(&arg_environ, optarg); + if (r < 0) + return r; + + break; + } + + case '?': + return -EINVAL; + + default: + log_error("Unknown option code %c", c); + return -EINVAL; + } + + if (optind == argc) { + log_error("Usage: %s [OPTION...] PROGRAM [OPTION...]", + program_invocation_short_name); + return -EINVAL; + } + + arg_args = argv + optind; + + return 1 /* work to do */; +} + +int main(int argc, char **argv, char **envp) { + int r, n; + int epoll_fd = -1; + + log_set_max_level(LOG_DEBUG); + log_show_color(true); + log_parse_environment(); + + 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; + + while (true) { + struct epoll_event event; + + r = epoll_wait(epoll_fd, &event, 1, -1); + if (r < 0) { + if (errno == EINTR) + continue; + + log_error("epoll_wait() failed: %m"); + return EXIT_FAILURE; + } + + log_info("Communication attempt on fd:%d", event.data.fd); + if (arg_accept) { + r = do_accept(argv[optind], argv + optind, envp, + event.data.fd); + if (r < 0) + return EXIT_FAILURE; + } else + break; + } + + launch(argv[optind], argv + optind, envp, n); + + return EXIT_SUCCESS; +} |