diff options
| -rw-r--r-- | src/mds-server.c | 150 | ||||
| -rw-r--r-- | src/mds-server.h | 8 |
2 files changed, 141 insertions, 17 deletions
diff --git a/src/mds-server.c b/src/mds-server.c index 7a50e7f..7bd49e1 100644 --- a/src/mds-server.c +++ b/src/mds-server.c @@ -22,6 +22,7 @@ #include <libmdsserver/fd-table.h> #include <libmdsserver/mds-message.h> +#include <alloca.h> #include <signal.h> #include <stdio.h> #include <string.h> @@ -102,7 +103,6 @@ int main(int argc_, char** argv_) int unparsed_args_ptr = 1; char* unparsed_args[ARGC_LIMIT + LIBEXEC_ARGC_EXTRA_LIMIT + 1]; int i; - pid_t pid; pthread_t _slave_thread; @@ -198,6 +198,8 @@ int main(int argc_, char** argv_) if (is_respawn == 0) { + pid_t pid; + /* Run mdsinitrc. */ pid = fork(); if (pid == (pid_t)-1) @@ -223,19 +225,37 @@ int main(int argc_, char** argv_) if (linked_list_create(&client_list, 32)) { perror(*argv); + fd_table_destroy(&client_map, NULL, NULL); linked_list_destroy(&client_list); return 1; } + /* Make the server update without all slaves dying on SIGUSR1. */ + { + struct sigaction action; + sigset_t sigset; + + sigemptyset(&sigset); + action.sa_handler = sigusr1_trap; + action.sa_mask = sigset; + action.sa_flags = 0; + + if (sigaction(SIGUSR1, &action, NULL) < 0) + { + perror(*argv); + fd_table_destroy(&client_map, NULL, NULL); + linked_list_destroy(&client_list); + return 1; + } + } + + /* Create mutex and condition for slave counter. */ pthread_mutex_init(&slave_mutex, NULL); pthread_cond_init(&slave_cond, NULL); - /* TODO make the server update without all slaves dying on SIGUSR1 */ - - /* Accepting incoming connections. */ while (running && (reexecing == 0)) { @@ -296,23 +316,85 @@ int main(int argc_, char** argv_) /* Release resources. */ fd_table_destroy(&client_map, NULL, NULL); linked_list_destroy(&client_list); + pthread_mutex_destroy(&slave_mutex); + pthread_cond_destroy(&slave_cond); return 0; reexec: - /* Join with all slaves threads. */ - pthread_mutex_lock(&slave_mutex); - while (running_slaves > 0) - pthread_cond_wait(&slave_cond, &slave_mutex); - pthread_mutex_unlock(&slave_mutex); - - /* TODO: marshal and exec */ - - /* Returning non-zero is important, otherwise the server cannot - be respawn if the re-exec fails. */ - perror(*argv); - return 1; + { + char* state_buf = NULL; + char* state_buf_; + size_t state_n; + ssize_t wrote; + int pipe_rw[2]; + char readlink_buf[PATH_MAX]; + ssize_t readlink_ptr; + char** reexec_args; + char** reexec_args_; + char reexec_arg[24]; +#if INT_MAX > UINT64_MAX +# error It seems int:s are really big, you might need to increase the size of reexec_arg. +#endif + + /* Release resources. */ + pthread_mutex_destroy(&slave_mutex); + pthread_cond_destroy(&slave_cond); + + /* Join with all slaves threads. */ + pthread_mutex_lock(&slave_mutex); + while (running_slaves > 0) + pthread_cond_wait(&slave_cond, &slave_mutex); + pthread_mutex_unlock(&slave_mutex); + + /* Marshal the state of the server. */ /* TODO marshal all data. */ + state_n = 2 * sizeof(int) + 1 * sizeof(sig_atomic_t); + state_buf = alloca(state_n); + state_buf_ = state_buf; + ((int*)state_buf_)[0] = MDS_SERVER_VARS_VERSION; + ((int*)state_buf_)[1] = socket_fd; + state_buf_ += 2 * sizeof(int) / sizeof(char); + ((sig_atomic_t*)state_buf_)[0] = running; + state_buf_ += 1 * sizeof(sig_atomic_t) / sizeof(char); + if (pipe(pipe_rw) < 0) + goto reexec_fail; + errno = 0; + while (state_n > 0) + { + wrote = write(pipe_rw[1], state_buf, state_n); + if (errno && (errno != EINTR)) + goto reexec_fail; + state_n -= (size_t)(wrote < 0 ? 0 : wrote); + state_buf += (size_t)(wrote < 0 ? 0 : wrote); + } + close(pipe_rw[1]); + + /* Re-exec the server. */ + readlink_ptr = readlink("/proc/self/exe", readlink_buf, PATH_MAX - 1); + if (readlink_ptr < 0) + goto reexec_fail; + /* ‘readlink() does not append a null byte to buf.’ */ + readlink_buf[readlink_ptr] = '\0'; + snprintf(reexec_arg, sizeof(reexec_arg) / sizeof(char), + "--re-exec=%i", pipe_rw[0]); + reexec_args = alloca(((size_t)argc + 2) * sizeof(char*)); + reexec_args_ = reexec_args; + *reexec_args_++ = *argv; + *reexec_args_ = reexec_arg; + for (i = 1; i < argc; i++) + reexec_args_[i] = argv[i]; + reexec_args_[argc] = NULL; + execv(readlink_buf, reexec_args); + + reexec_fail: + perror(*argv); + close(pipe_rw[0]); + close(pipe_rw[1]); + /* Returning non-zero is important, otherwise the server cannot + be respawn if the re-exec fails. */ + return 1; + } } @@ -326,11 +408,29 @@ void* slave_loop(void* data) { int socket_fd = (int)(intptr_t)data; ssize_t entry = LINKED_LIST_UNUSED; - client_t* information; + client_t* information = NULL; size_t tmp; int r; + /* Make the server update without all slaves dying on SIGUSR1. */ + { + struct sigaction action; + sigset_t sigset; + + sigemptyset(&sigset); + action.sa_handler = sigusr1_trap; + action.sa_mask = sigset; + action.sa_flags = 0; + + if (sigaction(SIGUSR1, &action, NULL) < 0) + { + perror(*argv); + goto fail; + } + } + + /* Create information table. */ information = malloc(sizeof(client_t)); if (information == NULL) @@ -537,3 +637,19 @@ void run_initrc(char** args) fprintf(stderr, "%s: unable to run %s file, you might as well kill me.\n", *argv, INITRC_FILE); } + +/** + * Called with the signal SIGUSR1 is caught. + * This function should cue a re-exec of the program. + * + * @param signo The caught signal + */ +void sigusr1_trap(int signo __attribute__((unused))) +{ + if (reexecing == 0) + { + reexecing = 1; + /* TODO send the signal to all threads. */ + } +} + diff --git a/src/mds-server.h b/src/mds-server.h index 7b03501..db1e122 100644 --- a/src/mds-server.h +++ b/src/mds-server.h @@ -75,6 +75,14 @@ char* getenv_nonempty(const char* var); */ void run_initrc(char** args); +/** + * Called with the signal SIGUSR1 is caught. + * This function should cue a re-exec of the program. + * + * @param signo The caught signal + */ +void sigusr1_trap(int signo); + #endif |