X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=server.c;h=e08b0661d14ddc4a8ef1cf2386cb75efe0655d19;hp=4822ebb5c3066404e46f72b8154acc6f452bde04;hb=343a65bc48b4e0cda4d9a14afcd7e96cca9c5de9;hpb=3cfb1d880ebf22546486316cb74cce21f007eb07 diff --git a/server.c b/server.c index 4822ebb5..e08b0661 100644 --- a/server.c +++ b/server.c @@ -14,7 +14,7 @@ * * * - The main programs: \ref server.c, \ref audiod.c, \ref client.c, - * \ref audioc.c, \ref fsck.c, \ref afh.c + * \ref audioc.c, \ref afh.c * - Server: \ref server_command, \ref sender, * - Audio file selector: \ref audio_format_handler, \ref mood, \ref afs_table, * - Client: \ref receiver, \ref receiver_node, \ref filter, \ref filter_node. @@ -47,7 +47,6 @@ * - Time: \ref time.c, * - Spawning processes: \ref exec.c, * - Inter process communication: \ref ipc.c, - * - The object storage layer: \ref osl.c, * - Blob tables: \ref blob.c, * - The error subssystem: \ref error.h. * - Access control for paraslash senders: \ref acl.c, \ref acl.h. @@ -55,16 +54,16 @@ * Low-level data structures: * * - Doubly linked lists: \ref list.h, - * - Red-black trees: \ref rbtree.h, \ref rbtree.c, * - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h, * - Hashing: \ref hash.h, \ref sha1.h, \ref sha1.c, * - Crypto: \ref crypt.c. - * + * - Forward error correction: \ref fec.c */ #include #include #include +#include #include "para.h" #include "error.h" @@ -115,7 +114,6 @@ int mmd_mutex; /** The file containing user information (public key, permissions). */ static char *user_list_file = NULL; -static int mmd_shm_id; /** The task responsible for server command handling. */ @@ -162,16 +160,16 @@ static void init_colors_or_die(void) static void init_ipc_or_die(void) { void *shm; - int ret = shm_new(sizeof(struct misc_meta_data)); + int shmid, ret = shm_new(sizeof(struct misc_meta_data)); if (ret < 0) goto err_out; - - ret = shm_attach(ret, ATTACH_RW, &shm); + shmid = ret; + ret = shm_attach(shmid, ATTACH_RW, &shm); + shm_destroy(shmid); if (ret < 0) goto err_out; mmd = shm; - mmd_shm_id = ret; ret = mutex_new(); if (ret < 0) @@ -228,7 +226,7 @@ void parse_config_or_die(int override) .initialize = 0, .check_required = 1, .check_ambiguity = 0, - .print_errors = 1 + .print_errors = !conf.daemon_given }; server_cmdline_parser_config_file(cf, &conf, ¶ms); conf.daemon_given = tmp; @@ -292,19 +290,36 @@ static void signal_post_select(struct sched *s, struct task *t) if (pid != mmd->afs_pid) continue; PARA_EMERG_LOG("fatal: afs died\n"); - goto genocide; + kill(0, SIGTERM); + goto cleanup; } break; /* die on sigint/sigterm. Kill all children too. */ case SIGINT: case SIGTERM: PARA_EMERG_LOG("terminating on signal %d\n", st->signum); -genocide: kill(0, SIGTERM); + /* + * We must wait for afs because afs catches SIGINT/SIGTERM. + * Before reacting to the signal, afs might want to use the + * shared memory area and the mmd mutex. If we destroy this + * mutex too early and afs tries to lock the shared memory + * area, the call to mutex_lock() will fail and terminate the + * afs process. This leads to dirty osl tables. + * + * There's no such problem with the other children of the + * server process (the command handlers) as these reset their + * SIGINT/SIGTERM handlers to the default action, i.e. these + * processes get killed immediately by the above kill(). + */ + PARA_INFO_LOG("waiting for afs (pid %d) to die\n", + (int)mmd->afs_pid); + waitpid(mmd->afs_pid, NULL, 0); +cleanup: + free(mmd->afd.afhi.chunk_table); + close_listed_fds(); mutex_destroy(mmd_mutex); shm_detach(mmd); - shm_destroy(mmd_shm_id); - exit(EXIT_FAILURE); } } @@ -318,27 +333,15 @@ static void init_signal_task(void) st->task.post_select = signal_post_select; sprintf(st->task.status, "signal task"); + PARA_NOTICE_LOG("setting up signal handling\n"); st->fd = para_signal_init(); /* always successful */ - - PARA_NOTICE_LOG("setting up signal handlers\n"); - if (para_install_sighandler(SIGINT) < 0) - goto err; - if (para_install_sighandler(SIGTERM) < 0) - goto err; - if (para_install_sighandler(SIGHUP) < 0) - goto err; - if (para_install_sighandler(SIGCHLD) < 0) - goto err; - if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) - goto err; - if (signal(SIGUSR1, SIG_IGN) == SIG_ERR) - goto err; + para_install_sighandler(SIGINT); + para_install_sighandler(SIGTERM); + para_install_sighandler(SIGHUP); + para_install_sighandler(SIGCHLD); + para_sigaction(SIGPIPE, SIG_IGN); add_close_on_fork_list(st->fd); register_task(&st->task); - return; -err: - PARA_EMERG_LOG("could not install signal handlers\n"); - exit(EXIT_FAILURE); } static void command_pre_select(struct sched *s, struct task *t) @@ -354,6 +357,7 @@ static void command_post_select(struct sched *s, struct task *t) int new_fd, ret, i; char *peer_name; pid_t child_pid; + uint32_t *chunk_table; if (!FD_ISSET(sct->listen_fd, &s->rfds)) return; @@ -366,6 +370,16 @@ static void command_post_select(struct sched *s, struct task *t) mmd->num_connects++; mmd->active_connections++; random(); + /* + * The chunk table is a pointer located in the mmd struct that point to + * dynamically allocated memory that must be freed by the parent and + * the child. However, as the mmd struct is in a shared memory area, + * there's no guarantee that after the fork these pointers are still + * valid in child context. As this pointer is not used in the child + * anyway, we save it to a local variable and free the memory via that + * copy in the child. + */ + chunk_table = mmd->afd.afhi.chunk_table; child_pid = fork(); if (child_pid < 0) { ret = -ERRNO_TO_PARA_ERROR(errno); @@ -376,6 +390,8 @@ static void command_post_select(struct sched *s, struct task *t) /* parent keeps accepting connections */ return; } + /* mmd might already have changed at this point */ + free(chunk_table); alarm(ALARM_TIMEOUT); close_listed_fds(); para_signal_shutdown(); @@ -472,6 +488,12 @@ static int init_afs(void) return afs_server_socket[0]; } +__noreturn static void tmp_sigchld_handler(__a_unused int s) +{ + PARA_EMERG_LOG("caught early SIGCHLD\n"); + exit(EXIT_FAILURE); +} + static void server_init(int argc, char **argv) { struct server_cmdline_parser_params params = { @@ -502,6 +524,21 @@ static void server_init(int argc, char **argv) daemonize(); PARA_NOTICE_LOG("initializing audio format handlers\n"); afh_init(); + + /* + * Although afs uses its own signal handling we must ignore SIGUSR1 + * _before_ the afs child process gets born by init_afs() below. It's + * racy to do this in the child because the parent might send SIGUSR1 + * before the child gets a chance to ignore this signal -- only the + * good die young. + */ + para_sigaction(SIGUSR1, SIG_IGN); + /* + * We have to install a SIGCHLD handler before the afs process is being + * forked off. Otherwise, para_server does not notice if afs dies before + * the SIGCHLD handler has been installed by init_signal_task() below. + */ + para_sigaction(SIGCHLD, tmp_sigchld_handler); PARA_NOTICE_LOG("initializing the audio file selector\n"); afs_socket = init_afs(); init_signal_task();