1 files changed, 548 insertions, 0 deletions

diff --git a/daemon/main.c b/daemon/main.c
new file mode 100644
index 0000000..dde99c2
--- /dev/null
+++ b/daemon/main.c
@@ -0,0 +1,548 @@
+/*
+        usbmuxd - iPhone/iPod Touch USB multiplex server daemon
+
+Copyright (C) 2009      Hector Martin "marcan" <hector@marcansoft.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 or version 3.
+
+This program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+*/
+
+#define _BSD_SOURCE
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <pwd.h>
+#include <grp.h>
+
+#include "log.h"
+#include "usb.h"
+#include "device.h"
+#include "client.h"
+
+static const char *socket_path = "/var/run/usbmuxd";
+static const char *lockfile = "/var/run/usbmuxd.pid";
+
+int should_exit;
+
+static int verbose = 0;
+static int foreground = 0;
+static int drop_privileges = 0;
+static const char *drop_user = "usbmux";
+static int opt_udev = 0;
+static int opt_exit = 0;
+static int exit_signal = 0;
+static int daemon_pipe;
+
+static int report_to_parent = 0;
+
+int create_socket(void) {
+        struct sockaddr_un bind_addr;
+        int listenfd;
+
+        if(unlink(socket_path) == -1 && errno != ENOENT) {
+                usbmuxd_log(LL_FATAL, "unlink(%s) failed: %s", socket_path, strerror(errno));
+                return -1;
+        }
+
+        listenfd = socket(AF_UNIX, SOCK_STREAM, 0);
+        if (listenfd == -1) {
+                usbmuxd_log(LL_FATAL, "socket() failed: %s", strerror(errno));
+                return -1;
+        }
+
+        bzero(&bind_addr, sizeof(bind_addr));
+        bind_addr.sun_family = AF_UNIX;
+        strcpy(bind_addr.sun_path, socket_path);
+        if (bind(listenfd, (struct sockaddr*)&bind_addr, sizeof(bind_addr)) != 0) {
+                usbmuxd_log(LL_FATAL, "bind() failed: %s", strerror(errno));
+                return -1;
+        }
+
+        // Start listening
+        if (listen(listenfd, 5) != 0) {
+                usbmuxd_log(LL_FATAL, "listen() failed: %s", strerror(errno));
+                return -1;
+        }
+
+        chmod(socket_path, 0666);
+
+        return listenfd;
+}
+
+void handle_signal(int sig)
+{
+        if (sig != SIGUSR1) {
+                usbmuxd_log(LL_NOTICE,"Caught signal %d, exiting", sig);
+                should_exit = 1;
+        } else {
+                if(opt_udev) {
+                        usbmuxd_log(LL_INFO, "Caught SIGUSR1, checking if we can terminate (no more devices attached)...");
+                        if (device_get_count() > 0) {
+                                // we can't quit, there are still devices attached.
+                                usbmuxd_log(LL_NOTICE, "Refusing to terminate, there are still devices attached. Kill me with signal 15 (TERM) to force quit.");
+                        } else {
+                                // it's safe to quit
+                                should_exit = 1;
+                        }
+                } else {
+                        usbmuxd_log(LL_INFO, "Caught SIGUSR1 but we weren't started in --udev mode, ignoring");
+                }
+        }
+}
+
+void set_signal_handlers(void)
+{
+        struct sigaction sa;
+        memset(&sa, 0, sizeof(struct sigaction));
+        sa.sa_handler = handle_signal;
+        sigaction(SIGINT, &sa, NULL);
+        sigaction(SIGQUIT, &sa, NULL);
+        sigaction(SIGTERM, &sa, NULL);
+        sigaction(SIGUSR1, &sa, NULL);
+}
+
+int main_loop(int listenfd)
+{
+        int to, cnt, i, dto;
+        struct fdlist pollfds;
+
+        while(!should_exit) {
+                usbmuxd_log(LL_FLOOD, "main_loop iteration");
+                to = usb_get_timeout();
+                usbmuxd_log(LL_FLOOD, "USB timeout is %d ms", to);
+                dto = device_get_timeout();
+                usbmuxd_log(LL_FLOOD, "Device timeout is %d ms", to);
+                if(dto < to)
+                        to = dto;
+
+                fdlist_create(&pollfds);
+                fdlist_add(&pollfds, FD_LISTEN, listenfd, POLLIN);
+                usb_get_fds(&pollfds);
+                client_get_fds(&pollfds);
+                usbmuxd_log(LL_FLOOD, "fd count is %d", pollfds.count);
+
+                cnt = poll(pollfds.fds, pollfds.count, to);
+                usbmuxd_log(LL_FLOOD, "poll() returned %d", cnt);
+
+                if(cnt == -1) {
+                        if(errno == EINTR && should_exit) {
+                                usbmuxd_log(LL_INFO, "event processing interrupted");
+                                fdlist_free(&pollfds);
+                                return 0;
+                        }
+                } else if(cnt == 0) {
+                        if(usb_process() < 0) {
+                                usbmuxd_log(LL_FATAL, "usb_process() failed");
+                                fdlist_free(&pollfds);
+                                return -1;
+                        }
+                        device_check_timeouts();
+                } else {
+                        int done_usb = 0;
+                        for(i=0; i<pollfds.count; i++) {
+                                if(pollfds.fds[i].revents) {
+                                        if(!done_usb && pollfds.owners[i] == FD_USB) {
+                                                if(usb_process() < 0) {
+                                                        usbmuxd_log(LL_FATAL, "usb_process() failed");
+                                                        fdlist_free(&pollfds);
+                                                        return -1;
+                                                }
+                                                done_usb = 1;
+                                        }
+                                        if(pollfds.owners[i] == FD_LISTEN) {
+                                                if(client_accept(listenfd) < 0) {
+                                                        usbmuxd_log(LL_FATAL, "client_accept() failed");
+                                                        fdlist_free(&pollfds);
+                                                        return -1;
+                                                }
+                                        }
+                                        if(pollfds.owners[i] == FD_CLIENT) {
+                                                client_process(pollfds.fds[i].fd, pollfds.fds[i].revents);
+                                        }
+                                }
+                        }
+                }
+                fdlist_free(&pollfds);
+        }
+        return 0;
+}
+
+/**
+ * make this program run detached from the current console
+ */
+static int daemonize(void)
+{
+        pid_t pid;
+        pid_t sid;
+        int pfd[2];
+        int res;
+
+        // already a daemon
+        if (getppid() == 1)
+                return 0;
+
+        if((res = pipe(pfd)) < 0) {
+                usbmuxd_log(LL_FATAL, "pipe() failed.");
+                return res;
+        }
+
+        pid = fork();
+        if (pid < 0) {
+                usbmuxd_log(LL_FATAL, "fork() failed.");
+                return pid;
+        }
+
+        if (pid > 0) {
+                // exit parent process
+                int status;
+                close(pfd[1]);
+
+                if((res = read(pfd[0],&status,sizeof(int))) != sizeof(int)) {
+                        fprintf(stderr, "usbmuxd: ERROR: Failed to get init status from child, check syslog for messages.\n");
+                        exit(1);
+                }
+                if(status != 0)
+                        fprintf(stderr, "usbmuxd: ERROR: Child process exited with error %d, check syslog for messages.\n", status);
+                exit(status);
+        }
+        // At this point we are executing as the child process
+        // but we need to do one more fork
+
+        daemon_pipe = pfd[1];
+        close(pfd[0]);
+        report_to_parent = 1;
+
+        // Change the file mode mask
+        umask(0);
+
+        // Create a new SID for the child process
+        sid = setsid();
+        if (sid < 0) {
+                usbmuxd_log(LL_FATAL, "setsid() failed.");
+                return -1;
+        }
+
+        pid = fork();
+        if (pid < 0) {
+                usbmuxd_log(LL_FATAL, "fork() failed (second).");
+                return pid;
+        }
+
+        if (pid > 0) {
+                // exit parent process
+                close(daemon_pipe);
+                exit(0);
+        }
+
+        // Change the current working directory.
+        if ((chdir("/")) < 0) {
+                usbmuxd_log(LL_FATAL, "chdir() failed");
+                return -2;
+        }
+        // Redirect standard files to /dev/null
+        if (!freopen("/dev/null", "r", stdin)) {
+                usbmuxd_log(LL_FATAL, "Redirection of stdin failed.");
+                return -3;
+        }
+        if (!freopen("/dev/null", "w", stdout)) {
+                usbmuxd_log(LL_FATAL, "Redirection of stdout failed.");
+                return -3;
+        }
+
+        return 0;
+}
+
+static int notify_parent(int status)
+{
+        int res;
+
+        report_to_parent = 0;
+        if ((res = write(daemon_pipe, &status, sizeof(int))) != sizeof(int)) {
+                usbmuxd_log(LL_FATAL, "Could not notify parent!");
+                if(res >= 0)
+                        return -2;
+                else
+                        return res;
+        }
+        close(daemon_pipe);
+        if (!freopen("/dev/null", "w", stderr)) {
+                usbmuxd_log(LL_FATAL, "Redirection of stderr failed.");
+                return -1;
+        }
+        return 0;
+}
+
+static void usage()
+{
+        printf("usage: usbmuxd [options]\n");
+        printf("\t-h|--help                 Print this message.\n");
+        printf("\t-v|--verbose              Be verbose (use twice or more to increase).\n");
+        printf("\t-f|--foreground           Do not daemonize (implies one -v).\n");
+        printf("\t-U|--user[=USER]          Change to this user after startup (needs usb privileges).\n");
+        printf("\t                          If USER is not specified, defaults to usbmux.\n");
+        printf("\t-u|--udev                 Run in udev operation mode.\n");
+        printf("\t-x|--exit                 Tell a running instance to exit if there are no devices\n");
+        printf("\t                          connected (must be in udev mode).\n");
+        printf("\t-X|--force-exit           Tell a running instance to exit, even if there are still\n");
+        printf("\t                          devices connected (always works).\n");
+        printf("\n");
+}
+
+static void parse_opts(int argc, char **argv)
+{
+        static struct option longopts[] = {
+                {"help", 0, NULL, 'h'},
+                {"foreground", 0, NULL, 'f'},
+                {"verbose", 0, NULL, 'v'},
+                {"user", 2, NULL, 'U'},
+                {"udev", 0, NULL, 'u'},
+                {"exit", 0, NULL, 'x'},
+                {"force-exit", 0, NULL, 'X'},
+                {NULL, 0, NULL, 0}
+        };
+        int c;
+
+        while (1) {
+                c = getopt_long(argc, argv, "hfvuU::xX", longopts, (int *) 0);
+                if (c == -1) {
+                        break;
+                }
+
+                switch (c) {
+                case 'h':
+                        usage();
+                        exit(0);
+                case 'f':
+                        foreground = 1;
+                        break;
+                case 'v':
+                        ++verbose;
+                        break;
+                case 'U':
+                        drop_privileges = 1;
+                        if(optarg)
+                                drop_user = optarg;
+                        break;
+                case 'u':
+                        opt_udev = 1;
+                        break;
+                case 'x':
+                        opt_exit = 1;
+                        exit_signal = SIGUSR1;
+                        break;
+                case 'X':
+                        opt_exit = 1;
+                        exit_signal = SIGTERM;
+                        break;
+                default:
+                        usage();
+                        exit(2);
+                }
+        }
+}
+
+int main(int argc, char *argv[])
+{
+        int listenfd;
+        int res = 0;
+        int lfd;
+        struct flock lock;
+        char pids[10];
+
+        parse_opts(argc, argv);
+
+        argc -= optind;
+        argv += optind;
+
+        if (!foreground) {
+                verbose += LL_WARNING;
+                log_enable_syslog();
+        } else {
+                verbose += LL_NOTICE;
+        }
+
+        /* set log level to specified verbosity */
+        log_level = verbose;
+
+        usbmuxd_log(LL_NOTICE, "usbmux v0.1 starting up");
+        should_exit = 0;
+
+        set_signal_handlers();
+
+        res = lfd = open(lockfile, O_WRONLY|O_CREAT, 0644);
+        if(res == -1) {
+                usbmuxd_log(LL_FATAL, "Could not open lockfile");
+                goto terminate;
+        }
+        lock.l_type = F_WRLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = 0;
+        lock.l_len = 0;
+        fcntl(lfd, F_GETLK, &lock);
+        close(lfd);
+        if (lock.l_type != F_UNLCK) {
+                if (opt_exit) {
+                        if (lock.l_pid && !kill(lock.l_pid, 0)) {
+                                usbmuxd_log(LL_NOTICE, "Sending signal %d to instance with pid %d", exit_signal, lock.l_pid);
+                                res = 0;
+                                if (kill(lock.l_pid, exit_signal) < 0) {
+                                        usbmuxd_log(LL_FATAL, "Could not deliver signal %d to pid %d", exit_signal, lock.l_pid);
+                                        res = -1;
+                                }
+                                goto terminate;
+                        } else {
+                                usbmuxd_log(LL_ERROR, "Could not determine pid of the other running instance!");
+                                res = -1;
+                                goto terminate;
+                        }
+                } else {
+                        if (!opt_udev) {
+                                usbmuxd_log(LL_ERROR, "Another instance is already running (pid %d). exiting.", lock.l_pid);
+                                res = -1;
+                        } else {
+                                usbmuxd_log(LL_NOTICE, "Another instance is already running (pid %d). exiting.", lock.l_pid);
+                                res = 0;
+                        }
+                        goto terminate;
+                }
+        }
+        unlink(lockfile);
+
+        if (opt_exit) {
+                usbmuxd_log(LL_NOTICE, "No running instance found, none killed. exiting.");
+                goto terminate;
+        }
+
+        if (!foreground) {
+                if ((res = daemonize()) < 0) {
+                        fprintf(stderr, "usbmuxd: FATAL: Could not daemonize!\n");
+                        usbmuxd_log(LL_FATAL, "Could not daemonize!");
+                        goto terminate;
+                }
+        }
+
+        // now open the lockfile and place the lock
+        res = lfd = open(lockfile, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL, 0644);
+        if(res < 0) {
+                usbmuxd_log(LL_FATAL, "Could not open lockfile");
+                goto terminate;
+        }
+        lock.l_type = F_WRLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = 0;
+        lock.l_len = 0;
+        if ((res = fcntl(lfd, F_SETLK, &lock)) < 0) {
+                usbmuxd_log(LL_FATAL, "Lockfile locking failed!");
+                goto terminate;
+        }
+        sprintf(pids, "%d", getpid());
+        if ((res = write(lfd, pids, strlen(pids))) != strlen(pids)) {
+                usbmuxd_log(LL_FATAL, "Could not write pidfile!");
+                if(res >= 0)
+                        res = -2;
+                goto terminate;
+        }
+
+        usbmuxd_log(LL_INFO, "Creating socket");
+        res = listenfd = create_socket();
+        if(listenfd < 0)
+                goto terminate;
+
+        // drop elevated privileges
+        if (drop_privileges && (getuid() == 0 || geteuid() == 0)) {
+                struct passwd *pw = getpwnam(drop_user);
+                if (!pw) {
+                        usbmuxd_log(LL_FATAL, "Dropping privileges failed, check if user '%s' exists!", drop_user);
+                        res = -1;
+                        goto terminate;
+                }
+
+                if ((res = initgroups(drop_user, pw->pw_gid)) < 0) {
+                        usbmuxd_log(LL_FATAL, "Failed to drop privileges (cannot set supplementary groups)");
+                        goto terminate;
+                }
+                if ((res = setgid(pw->pw_gid)) < 0) {
+                        usbmuxd_log(LL_FATAL, "Failed to drop privileges (cannot set group ID to %d)", pw->pw_gid);
+                        goto terminate;
+                }
+                if ((res = setuid(pw->pw_uid)) < 0) {
+                        usbmuxd_log(LL_FATAL, "Failed to drop privileges (cannot set user ID to %d)", pw->pw_uid);
+                        goto terminate;
+                }
+
+                // security check
+                if (setuid(0) != -1) {
+                        usbmuxd_log(LL_FATAL, "Failed to drop privileges properly!");
+                        res = -1;
+                        goto terminate;
+                }
+                if (getuid() != pw->pw_uid || getgid() != pw->pw_gid) {
+                        usbmuxd_log(LL_FATAL, "Failed to drop privileges properly!");
+                        res = -1;
+                        goto terminate;
+                }
+                usbmuxd_log(LL_NOTICE, "Successfully dropped privileges to '%s'", drop_user);
+        }
+
+        client_init();
+        device_init();
+        usbmuxd_log(LL_INFO, "Initializing USB");
+        if((res = usb_init()) < 0)
+                goto terminate;
+
+        usbmuxd_log(LL_INFO, "%d device%s detected", res, (res==1)?"":"s");
+
+        usbmuxd_log(LL_NOTICE, "Initialization complete");
+
+        if (report_to_parent)
+                if((res = notify_parent(0)) < 0)
+                        goto terminate;
+
+        res = main_loop(listenfd);
+        if(res < 0)
+                usbmuxd_log(LL_FATAL, "main_loop failed");
+
+        usbmuxd_log(LL_NOTICE, "usbmux shutting down");
+        device_kill_connections();
+        usb_shutdown();
+        device_shutdown();
+        client_shutdown();
+        usbmuxd_log(LL_NOTICE, "Shutdown complete");
+
+terminate:
+        log_disable_syslog();
+
+        if (res < 0)
+                res = -res;
+        else
+                res = 0;
+        if (report_to_parent)
+                notify_parent(res);
+
+        return res;
+}