X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=command.c;h=aea48146a38cefd7aeb22ea2994c9d53b5633c08;hb=0c35f5c1692909134436cedac65b7c872a0b0867;hp=cd24c0350ef90fbeccf713325738a6b03eba1000;hpb=0b786d977ded3c3922e851e5b8d60837b43469b9;p=paraslash.git

diff --git a/command.c b/command.c
index cd24c035..aea48146 100644
--- a/command.c
+++ b/command.c
@@ -49,9 +49,14 @@ static const char * const server_command_perms_txt[] = {LSG_SERVER_CMD_AUX_INFOS
 extern int mmd_mutex;
 extern struct misc_meta_data *mmd;
 int send_afs_status(struct command_context *cc, int parser_friendly);
+static bool subcmd_should_die;
 
-static void dummy(__a_unused int s)
+static void command_handler_sighandler(int s)
 {
+	if (s != SIGTERM)
+		return;
+	PARA_EMERG_LOG("terminating on signal %d\n", SIGTERM);
+	subcmd_should_die = true;
 }
 
 /*
@@ -492,9 +497,21 @@ static int com_stat(struct command_context *cc, struct lls_parse_result *lpr)
 	bool parser_friendly = SERVER_CMD_OPT_GIVEN(STAT, PARSER_FRIENDLY,
 		lpr) > 0;
 	uint32_t num = SERVER_CMD_UINT32_VAL(STAT, NUM, lpr);
+	const struct timespec ts = {.tv_sec = 50, .tv_nsec = 0};
 
-	para_sigaction(SIGUSR1, dummy);
+	para_sigaction(SIGINT, SIG_IGN);
+	para_sigaction(SIGUSR1, command_handler_sighandler);
+	para_sigaction(SIGTERM, command_handler_sighandler);
+	/*
+	 * Simply checking subcmd_should_die is racy because a signal may
+	 * arrive after the check but before the subsequent call to sleep(3).
+	 * If this happens, sleep(3) would not be interrupted by the signal.
+	 * To avoid this we block SIGTERM here and allow it to arrive only
+	 * while we sleep.
+	 */
+	para_block_signal(SIGTERM);
 	for (;;) {
+		sigset_t set;
 		/*
 		 * Copy the mmd structure to minimize the time we hold the mmd
 		 * lock.
@@ -517,7 +534,15 @@ static int com_stat(struct command_context *cc, struct lls_parse_result *lpr)
 		ret = 1;
 		if (num > 0 && !--num)
 			goto out;
-		sleep(50);
+		sigemptyset(&set); /* empty set means: unblock all signals */
+		/*
+		 * pselect(2) allows to atomically unblock signals, then go to
+		 * sleep. Calling sigprocmask(2) followed by sleep(3) would
+		 * open a race window similar to the one described above.
+		 */
+		pselect(1, NULL, NULL, NULL, &ts, &set);
+		if (subcmd_should_die)
+			goto out;
 		ret = -E_SERVER_CRASH;
 		if (getppid() == 1)
 			goto out;
@@ -759,7 +784,7 @@ struct connection_features {
 	int dummy; /* none at the moment */
 };
 
-static int parse_auth_request(char *buf, int len, struct user **u,
+static int parse_auth_request(char *buf, int len, const struct user **u,
 		struct connection_features *cf)
 {
 	int ret;
@@ -793,7 +818,7 @@ static int parse_auth_request(char *buf, int len, struct user **u,
 		}
 	}
 	PARA_DEBUG_LOG("received auth request for user %s\n", username);
-	*u = lookup_user(username);
+	*u = user_list_lookup(username);
 	ret = 1;
 out:
 	free_argv(features);
@@ -877,7 +902,7 @@ static int run_command(struct command_context *cc, struct iovec *iov)
  *
  * \sa alarm(2), \ref crypt.c, \ref crypt.h.
  */
-__noreturn void handle_connect(int fd)
+int handle_connect(int fd)
 {
 	int ret;
 	unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
@@ -987,5 +1012,5 @@ out:
 	}
 	sc_free(cc->scc.recv);
 	sc_free(cc->scc.send);
-	exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
+	return ret;
 }