diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/config.h | 24 | ||||
| -rw-r--r-- | src/mds.c | 125 | ||||
| -rw-r--r-- | src/mds.h | 9 |
3 files changed, 155 insertions, 3 deletions
diff --git a/src/config.h b/src/config.h index ef49b4d..df7f81a 100644 --- a/src/config.h +++ b/src/config.h @@ -86,6 +86,14 @@ /** + * The number of additional arguments a libexec server may have + */ +#ifndef LIBEXEC_ARGC_EXTRA_LIMIT +#define LIBEXEC_ARGC_EXTRA_LIMIT 5 +#endif + + +/** * The maximum number of display allowed on the system */ #ifndef DISPLAY_MAX @@ -102,5 +110,21 @@ #endif +/** + * The directory where all servers are installed + */ +#ifndef LIBEXECDIR +#define LIBEXECDIR "/usr/libexec" +#endif + + +/** + * The minimum time that most have elapsed for respawning to be allowed. + */ +#ifndef RESPAWN_TIME_LIMIT_SECONDS +#define RESPAWN_TIME_LIMIT_SECONDS 5 +#endif + + #endif @@ -30,6 +30,8 @@ #include <signal.h> #include <sys/socket.h> #include <sys/un.h> +#include <sys/wait.h> +#include <time.h> /** @@ -40,7 +42,7 @@ static int argc; /** * Command line arguments */ -static const char** argv; +static char** argv; /** @@ -50,7 +52,7 @@ static const char** argv; * @param argv_ Command line arguments * @return Non-zero on error */ -int main(int argc_, const char** argv_) +int main(int argc_, char** argv_) { struct sockaddr_un address; char pathname[PATH_MAX]; @@ -58,6 +60,7 @@ int main(int argc_, const char** argv_) unsigned int display; int fd; FILE *f; + int rc; argc = argc_; @@ -178,7 +181,7 @@ int main(int argc_, const char** argv_) /* Save MDS_DISPLAY environment variable. */ snprintf(pathname, sizeof(pathname) / sizeof(char), /* Excuse the reuse without renaming. */ - "%s=%u", DISPLAY_ENV, display); + "%s=:%u", DISPLAY_ENV, display); putenv(pathname); /* Create display socket. */ @@ -219,6 +222,122 @@ int main(int argc_, const char** argv_) return 1; } + /* Start master server and respawn it if it crashes. */ + rc = spawn_and_respawn_server(fd); + + /* Shutdown, close and remove the socket. */ + shutdown(fd, SHUT_RDWR); + close(fd); + unlink(pathname); + + return rc; +} + + +/** + * Start master server and respawn it if it crashes + * + * @param fd The file descriptor of the socket + * @return Non-zero on error + */ +int spawn_and_respawn_server(int fd) +{ + struct timespec time_start; + struct timespec time_end; + char* child_args[ARGC_LIMIT + LIBEXEC_ARGC_EXTRA_LIMIT + 1]; + char pathname[PATH_MAX]; + char fdstr[64]; + int i; + pid_t pid; + int status; + int time_error = 0; + int first_spawn = 1; + + snprintf(pathname, sizeof(pathname) / sizeof(char), "%s/mds-master", LIBEXECDIR); + child_args[0] = pathname; + + for (i = 1; i < argc; i++) + child_args[i] = argv[i]; + + child_args[argc + 0] = strdup("--initial-spawn"); + child_args[argc + 1] = strdup("--socket-fd"); + snprintf(fdstr, sizeof(fdstr) / sizeof(char), "%i", fd); + child_args[argc + 2] = fdstr; + child_args[argc + 3] = NULL; + +#if (LIBEXEC_ARGC_EXTRA_LIMIT < 3) +# error LIBEXEC_ARGC_EXTRA_LIMIT is too small, need at least 3. +#endif + + for (;;) + { + pid = fork(); + if (pid == (pid_t)-1) + { + perror(*argv); + return 1; + } + + if (pid) + { + /* Get the current time. (Start of child process.) */ + time_error = (clock_gettime(CLOCK_MONOTONIC, &time_start) < 0); + if (time_error) + perror(*argv); + + /* Wait for master server to die. */ + if (waitpid(pid, &status, 0) == (pid_t)-1) + { + perror(*argv); + return 1; + } + + /* If the server exited normally or SIGTERM, do not respawn. */ + if (WIFEXITED(status) || (WEXITSTATUS(status) && WTERMSIG(status))) + break; + + /* Get the current time. (End of child process.) */ + time_error |= (clock_gettime(CLOCK_MONOTONIC, &time_end) < 0); + + /* Do not respawn if we could not read the time. */ + if (time_error) + { + perror(*argv); + fprintf(stderr, + "%s: %s died abnormally, not respoawning because we could not read the time.\n", + *argv, pathname); + return 1; + } + + /* Respawn if the server did not die too fast. */ + if (time_end.tv_sec - time_start.tv_sec < RESPAWN_TIME_LIMIT_SECONDS) + fprintf(stderr, "%s: %s died abnormally, respawning.\n", *argv, pathname); + else + { + fprintf(stderr, + "%s: %s died abnormally, died too fast, not respawning.\n", + *argv, pathname); + return 1; + } + + if (first_spawn) + { + first_spawn = 0; + free(child_args[argc + 0]); + child_args[argc + 0] = strdup("--respawn"); + } + } + else + { + /* Start master server. */ + execv(pathname, child_args); + perror(*argv); + return 1; + } + } + + free(child_args[argc + 0]); + free(child_args[argc + 1]); return 0; } @@ -20,6 +20,15 @@ /** + * Start master server and respawn it if it crashes + * + * @param fd The file descriptor of the socket + * @return Non-zero on error + */ +int spawn_and_respawn_server(int fd); + + +/** * Create directory for socket files, PID files and such * * @return Non-zero on error |