diff options
Diffstat (limited to 'src/fastd.c')
| -rw-r--r-- | src/fastd.c | 157 |
1 files changed, 133 insertions, 24 deletions
diff --git a/src/fastd.c b/src/fastd.c index 3cc7d37..a9cb0c4 100644 --- a/src/fastd.c +++ b/src/fastd.c @@ -39,6 +39,7 @@ #include <string.h> #include <syslog.h> #include <sys/resource.h> +#include <sys/wait.h> #ifdef HAVE_LIBSODIUM #include <sodium/core.h> @@ -68,34 +69,49 @@ static void on_sigusr1(int signo UNUSED) { dump = true; } +static void on_sigchld(int signo UNUSED) { +} + static void init_signals(fastd_context_t *ctx) { struct sigaction action; action.sa_flags = 0; sigemptyset(&action.sa_mask); + /* unblock all signals */ + sigprocmask(SIG_SETMASK, &action.sa_mask, NULL); + action.sa_handler = on_sighup; - if(sigaction(SIGHUP, &action, NULL)) + if (sigaction(SIGHUP, &action, NULL)) exit_errno(ctx, "sigaction"); action.sa_handler = on_terminate; - if(sigaction(SIGTERM, &action, NULL)) + if (sigaction(SIGTERM, &action, NULL)) exit_errno(ctx, "sigaction"); - if(sigaction(SIGQUIT, &action, NULL)) + if (sigaction(SIGQUIT, &action, NULL)) exit_errno(ctx, "sigaction"); - if(sigaction(SIGINT, &action, NULL)) + if (sigaction(SIGINT, &action, NULL)) exit_errno(ctx, "sigaction"); action.sa_handler = on_sigusr1; - if(sigaction(SIGUSR1, &action, NULL)) + if (sigaction(SIGUSR1, &action, NULL)) + exit_errno(ctx, "sigaction"); + + action.sa_handler = on_sigchld; + if (sigaction(SIGCHLD, &action, NULL)) exit_errno(ctx, "sigaction"); action.sa_handler = SIG_IGN; - if(sigaction(SIGPIPE, &action, NULL)) + if (sigaction(SIGPIPE, &action, NULL)) + exit_errno(ctx, "sigaction"); + if (sigaction(SIGTTIN, &action, NULL)) + exit_errno(ctx, "sigaction"); + if (sigaction(SIGTTOU, &action, NULL)) exit_errno(ctx, "sigaction"); + } -static void init_pipes(fastd_context_t *ctx) { +static void open_pipe(fastd_context_t *ctx, int *readfd, int *writefd) { int pipefd[2]; if (pipe(pipefd)) @@ -104,8 +120,12 @@ static void init_pipes(fastd_context_t *ctx) { fastd_setfd(ctx, pipefd[0], FD_CLOEXEC, 0); fastd_setfd(ctx, pipefd[1], FD_CLOEXEC, 0); - ctx->resolverfd = pipefd[0]; - ctx->resolvewfd = pipefd[1]; + *readfd = pipefd[0]; + *writefd = pipefd[1]; +} + +static inline void init_pipes(fastd_context_t *ctx) { + open_pipe(ctx, &ctx->resolverfd, &ctx->resolvewfd); } static void init_log(fastd_context_t *ctx) { @@ -737,6 +757,96 @@ static void drop_caps(fastd_context_t *ctx) { fastd_cap_drop(ctx); } +/* will double fork and forward potential exit codes from the child to the parent */ +static int daemonize(fastd_context_t *ctx) { + static const uint8_t ERROR_STATUS = 1; + + uint8_t status = 1; + int parent_rpipe, parent_wpipe; + open_pipe(ctx, &parent_rpipe, &parent_wpipe); + + pid_t fork1 = fork(); + + if (fork1 < 0) { + exit_errno(ctx, "fork"); + } + else if (fork1 == 0) { + /* child 1 */ + if (close(parent_rpipe) < 0) + pr_error_errno(ctx, "close"); + + if (setsid() < 0) + pr_error_errno(ctx, "setsid"); + + int child_rpipe, child_wpipe; + open_pipe(ctx, &child_rpipe, &child_wpipe); + + pid_t fork2 = fork(); + + if (fork2 < 0) { + write(parent_wpipe, &ERROR_STATUS, 1); + exit_errno(ctx, "fork"); + } + else if (fork2 == 0) { + /* child 2 */ + + if (close(child_rpipe) < 0 || close(parent_wpipe) < 0) { + write(child_wpipe, &ERROR_STATUS, 1); + pr_error_errno(ctx, "close"); + } + + return child_wpipe; + } + else { + /* still child 1 */ + int child_status; + pid_t ret; + do { + if (read(child_rpipe, &status, 1) > 0) { + write(parent_wpipe, &status, 1); + exit(0); + } + + ret = waitpid(fork2, &child_status, WNOHANG); + } while (!ret); + + if (ret < 0) { + write(child_wpipe, &ERROR_STATUS, 1); + pr_error_errno(ctx, "waitpid"); + } + + if (WIFEXITED(child_status)) { + status = WEXITSTATUS(child_status); + write(parent_wpipe, &status, 1); + exit(status); + } + else { + write(parent_wpipe, &ERROR_STATUS, 1); + if (WIFSIGNALED(child_status)) + exit_error(ctx, "child exited with signal %i", WTERMSIG(child_status)); + exit(1); + } + } + } + else { + /* parent */ + struct sigaction action; + action.sa_flags = 0; + sigemptyset(&action.sa_mask); + action.sa_handler = SIG_IGN; + + if (sigaction(SIGCHLD, &action, NULL)) + exit_errno(ctx, "sigaction"); + + if (read(parent_rpipe, &status, 1) < 0) + exit_errno(ctx, "read"); + + exit(status); + } + + return -1; +} + int main(int argc, char *argv[]) { #ifdef HAVE_LIBSODIUM sodium_init(); @@ -749,6 +859,7 @@ int main(int argc, char *argv[]) { #endif fastd_context_t ctx = {}; + int status_fd = -1; close_fds(&ctx); @@ -771,9 +882,13 @@ int main(int argc, char *argv[]) { exit(0); } - init_log(&ctx); init_signals(&ctx); + if (conf.daemon) + status_fd = daemonize(&ctx); + + init_log(&ctx); + update_time(&ctx); conf.long_ago = ctx.now; @@ -799,21 +914,15 @@ int main(int argc, char *argv[]) { fastd_tuntap_open(&ctx); init_peer_groups(&ctx); - if (conf.daemon) { - pid_t pid = fork(); - if (pid < 0) { - exit_errno(&ctx, "fork"); - } - else if (pid > 0) { - write_pid(&ctx, pid); - exit(0); - } - if (setsid() < 0) - pr_error_errno(&ctx, "setsid"); - } - else { - write_pid(&ctx, getpid()); + write_pid(&ctx, getpid()); + + if (status_fd >= 0) { + static const uint8_t STATUS = 0; + if (write(status_fd, &STATUS, 1) < 0) + exit_errno(&ctx, "status: write"); + if (close(status_fd)) + exit_errno(&ctx, "status: close"); } if (conf.drop_caps == DROP_CAPS_EARLY) |