Restore stderr/stdout before calling panic_action (if in foreground m…

…ode)

Rename fr_log_t field dest to dst to match the macros

src/include/libradius.h

@@ -758,13 +758,25 @@ void		fr_cbuff_rp_insert(fr_cbuff_t *cbuff, void *obj);
 void		*fr_cbuff_rp_next(fr_cbuff_t *cbuff, TALLOC_CTX *ctx);
 
 /* debug.c */
+
+/** Optional callback passed to fr_fault_setup
+ *
+ * Allows optional logic to be run before calling the main fault handler.
+ *
+ * If the callback returns < 0, the main fault handler will not be called.
+ *
+ * @param signum signal raised.
+ * @return 0 on success < 0 on failure.
+ */
+typedef int (*fr_fault_cb)(int signum);
 typedef struct fr_bt_marker fr_bt_marker_t;
 
 void		fr_debug_break(void);
 void		backtrace_print(fr_cbuff_t *cbuff, void *obj);
 fr_bt_marker_t	*fr_backtrace_attach(fr_cbuff_t **cbuff, TALLOC_CTX *obj);
 void NEVER_RETURNS fr_fault(int sig);
 int		fr_fault_setup(char const *cmd, char const *program);
+void		fr_fault_set_cb(fr_fault_cb cb);
 
 /* rbtree.c */
 typedef struct rbtree_t rbtree_t;

src/include/log.h

@@ -66,7 +66,7 @@ typedef struct fr_log_t {
 	int		colourise;	//!< Prefix log messages with VT100 escape codes to change text
 					//!< colour.
 	int		fd;		//!< File descriptor to write messages to.
-	log_dst_t	dest;		//!< Log destination.
+	log_dst_t	dst;		//!< Log destination.
 	char		*file;		//!< Path to log file.
 	char		*debug_file;	//!< Path to debug log file.
 } fr_log_t;
@@ -77,6 +77,10 @@ extern FR_NAME_NUMBER const syslog_str2fac[];
 extern FR_NAME_NUMBER const log_str2dst[];
 extern fr_log_t default_log;
 
+bool radlog_std_restore(void);
+bool radlog_std_to_log(fr_log_t *log);
+int radlog_init(fr_log_t *log, bool close_std);
+
 int		vradlog(log_type_t lvl, char const *fmt, va_list ap)
 #ifdef __GNUC__
 		__attribute__ ((format (printf, 2, 0)))

src/lib/debug.c

@@ -61,6 +61,7 @@ struct fr_bt_marker {
 #endif
 
 static char panic_action[512];
+static fr_fault_cb panic_cb;
 static int fr_debugger_present = -1;
 
 /** Stub callback to see if the SIGTRAP handler is overriden
@@ -73,12 +74,12 @@ static void _sigtrap_handler(UNUSED int signum)
     signal(SIGTRAP, SIG_DFL);
 }
 
-/** Break in GDB (if were running under GDB)
+/** Break in debugger (if were running under a debugger)
  *
- * If the server is running under GDB this will raise a SIGTRAP which
- * will pause the running process.
+ * If the server is running under a debugger this will raise a
+ * SIGTRAP which will pause the running process.
  *
- * If the server is not running under GDB then this will do nothing.
+ * If the server is not running under debugger then this will do nothing.
  */
 void fr_debug_break(void)
 {
@@ -237,6 +238,11 @@ void NEVER_RETURNS fr_fault(int sig)
 
 	fprintf(stderr, "FATAL SIGNAL: %s\n", strsignal(sig));
 
+	/*
+	 *	Run the callback if one was registered
+	 */
+	if (panic_cb && (panic_cb(sig) < 0)) fr_exit_now(1);
+
 	/*
 	 *	Produce a simple backtrace - They've very basic but at least give us an
 	 *	idea of the area of the code we hit the issue in.
@@ -353,3 +359,12 @@ int fr_fault_setup(char const *cmd, char const *program)
 	return 0;
 }
 
+/** Set a callback to be called before fr_fault()
+ *
+ * @param cb to execute. If callback returns < 0
+ *	fr_fault will exit before running panic_action code.
+ */
+void fr_fault_set_cb(fr_fault_cb cb)
+{
+	panic_cb = cb;
+};

src/main/command.c

@@ -810,7 +810,7 @@ static char debug_log_file_buffer[1024];
 
 static int command_debug_file(rad_listen_t *listener, int argc, char *argv[])
 {
-	if (debug_flag && default_log.dest == L_DST_STDOUT) {
+	if (debug_flag && default_log.dst == L_DST_STDOUT) {
 		cprintf(listener, "ERROR: Cannot redirect debug logs to a file when already in debugging mode.\n");
 		return -1;
 	}

src/main/log.c

@@ -36,6 +36,8 @@ RCSID("$Id$")
 #  include <syslog.h>
 #endif
 
+#include <sys/file.h>
+
 /*
  * Logging facility names
  */
@@ -152,11 +154,138 @@ bool log_dates_utc = false;
 fr_log_t default_log = {
 	.colourise = true,
 	.fd = STDOUT_FILENO,
-	.dest = L_DST_STDOUT,
+	.dst = L_DST_STDOUT,
 	.file = NULL,
 	.debug_file = NULL,
 };
 
+static int stderr_fd = -1;	//!< The original unmolested stderr file descriptor
+static int stdout_fd = -1;	//!< The original unmolested stdout file descriptor
+
+/** Restore the original stderr/stdout file descriptors
+ *
+ * Only effective if radlog_init was called with close_stdout = false.
+ *
+ * @return true if stdout/stderr have been restored, else false.
+ */
+bool radlog_std_restore(void)
+{
+	if ((stderr_fd > 0) && (stdout_fd > 0)) {
+		dup2(stderr_fd, STDOUT_FILENO);
+		dup2(stdout_fd, STDERR_FILENO);
+		return true;
+	}
+	return false;
+}
+
+/** Set stderr/stdout to the current log descriptor.
+ *
+ * @param log Logger to manipulate.
+ * @return true if stdout/stderr have been altered, else false.
+ */
+bool radlog_std_to_log(fr_log_t *log)
+{
+	if (log->fd > 0) {
+		dup2(log->fd, STDOUT_FILENO);
+		dup2(log->fd, STDERR_FILENO);
+		return true;
+	}
+	return false;
+}
+
+/** Initialise file descriptors based on logging destination
+ *
+ * @param log Logger to manipulate.
+ * @param close_std Whether we should close stderr and stdout completely, or just redirect them.
+ * @return 0 on success -1 on failure.
+ */
+int radlog_init(fr_log_t *log, bool close_std)
+{
+	int devnull;
+
+	devnull = open("/dev/null", O_RDWR);
+	if (devnull < 0) {
+		fr_strerror_printf("Error opening /dev/null: %s", fr_syserror(errno));
+		return -1;
+	}
+
+	/*
+	 *	Dup the original stdout/stderr file descriptors so
+	 *	we can restore them later.
+	 */
+	if (!close_std) {
+		stderr_fd = dup(STDERR_FILENO);
+		stdout_fd = dup(STDOUT_FILENO);
+	}
+
+	/*
+	 *	STDOUT & STDERR go to /dev/null, unless we have "-x",
+	 *	then STDOUT & STDERR go to the "-l log" destination.
+	 *
+	 *	The complexity here is because "-l log" can go to
+	 *	STDOUT or STDERR, too.
+	 */
+	if (log->dst == L_DST_STDOUT) {
+		setlinebuf(stdout);
+		log->fd = STDOUT_FILENO;
+
+		/*
+		 *	If we're debugging, allow STDERR to go to
+		 *	STDOUT too, for executed programs,
+		 */
+		if (debug_flag) {
+			dup2(STDOUT_FILENO, STDERR_FILENO);
+		} else {
+			dup2(devnull, STDERR_FILENO);
+		}
+
+	} else if (log->dst == L_DST_STDERR) {
+		setlinebuf(stderr);
+		log->fd = STDERR_FILENO;
+
+		/*
+		 *	If we're debugging, allow STDOUT to go to
+		 *	STDERR too, for executed programs,
+		 */
+		if (debug_flag) {
+			dup2(STDERR_FILENO, STDOUT_FILENO);
+		} else {
+			dup2(devnull, STDOUT_FILENO);
+		}
+
+	} else if (log->dst == L_DST_SYSLOG) {
+		/*
+		 *	Discard STDOUT and STDERR no matter what the
+		 *	status of debugging.  Syslog isn't a file
+		 *	descriptor, so we can't use it.
+		 */
+		dup2(devnull, STDOUT_FILENO);
+		dup2(devnull, STDERR_FILENO);
+
+	} else if (debug_flag) {
+		/*
+		 *	If we're debugging, allow STDOUT and STDERR to
+		 *	go to the log file.
+		 */
+		radlog_std_to_log(log);
+
+	} else {
+		/*
+		 *	Not debugging, and the log isn't STDOUT or
+		 *	STDERR.  Ensure that we move both of them to
+		 *	/dev/null, so that the calling terminal can
+		 *	exit, and the output from executed programs
+		 *	doesn't pollute STDOUT / STDERR.
+		 */
+		dup2(devnull, STDOUT_FILENO);
+		dup2(devnull, STDERR_FILENO);
+	}
+
+	close(devnull);
+
+	return 0;
+}
+
 /*
  *	Log the message to the logfile. Include the severity and
  *	a time stamp.
@@ -182,7 +311,7 @@ int vradlog(log_type_t type, char const *fmt, va_list ap)
 	 *	If we don't want any messages, then
 	 *	throw them away.
 	 */
-	if (default_log.dest == L_DST_NULL) {
+	if (default_log.dst == L_DST_NULL) {
 		return 0;
 	}
 
@@ -209,7 +338,7 @@ int vradlog(log_type_t type, char const *fmt, va_list ap)
 	 *	Print timestamps for non-debugging, and for high levels
 	 *	of debugging.
 	 */
-	if (default_log.dest != L_DST_SYSLOG) {
+	if (default_log.dst != L_DST_SYSLOG) {
 		if ((debug_flag != 1) && (debug_flag != 2)) {
 			time_t timeval;
 
@@ -262,7 +391,7 @@ int vradlog(log_type_t type, char const *fmt, va_list ap)
 		buffer[sizeof(buffer) - 1] = '\0';
 	}
 
-	switch (default_log.dest) {
+	switch (default_log.dst) {
 
 #ifdef HAVE_SYSLOG_H
 	case L_DST_SYSLOG:

src/main/mainconfig.c

@@ -690,7 +690,7 @@ static int switch_users(CONF_SECTION *cs)
 	 *	specified on the command-line.
 	 */
 	if (uid_name || gid_name) {
-		if ((default_log.dest == L_DST_FILES) &&
+		if ((default_log.dst == L_DST_FILES) &&
 		    (default_log.fd < 0)) {
 			default_log.fd = open(mainconfig.log_file,
 					      O_WRONLY | O_APPEND | O_CREAT, 0640);
@@ -860,7 +860,7 @@ int read_mainconfig(int reload)
 	 *	If there was no log destination set on the command line,
 	 *	set it now.
 	 */
-	if (default_log.dest == L_DST_NULL) {
+	if (default_log.dst == L_DST_NULL) {
 		if (cf_section_parse(cs, NULL, serverdest_config) < 0) {
 			fprintf(stderr, "radiusd: Error: Failed to parse log{} section.\n");
 			cf_file_free(cs);
@@ -873,16 +873,16 @@ int read_mainconfig(int reload)
 			return -1;
 		}
 
-		default_log.dest = fr_str2int(log_str2dst, radlog_dest,
+		default_log.dst = fr_str2int(log_str2dst, radlog_dest,
 					      L_DST_NUM_DEST);
-		if (default_log.dest == L_DST_NUM_DEST) {
+		if (default_log.dst == L_DST_NUM_DEST) {
 			fprintf(stderr, "radiusd: Error: Unknown log_destination %s\n",
 				radlog_dest);
 			cf_file_free(cs);
 			return -1;
 		}
 
-		if (default_log.dest == L_DST_SYSLOG) {
+		if (default_log.dst == L_DST_SYSLOG) {
 			/*
 			 *	Make sure syslog_facility isn't NULL
 			 *	before using it
@@ -908,7 +908,7 @@ int read_mainconfig(int reload)
 			openlog(progname, LOG_PID, mainconfig.syslog_facility);
 #endif
 
-		} else if (default_log.dest == L_DST_FILES) {
+		} else if (default_log.dst == L_DST_FILES) {
 			if (!mainconfig.log_file) {
 				fprintf(stderr, "radiusd: Error: Specified \"files\" as a log destination, but no log filename was given!\n");
 				cf_file_free(cs);
@@ -929,7 +929,7 @@ int read_mainconfig(int reload)
 	 *	did switch uid/gid, then the code in switch_users()
 	 *	took care of setting the file permissions correctly.
 	 */
-	if ((default_log.dest == L_DST_FILES) &&
+	if ((default_log.dst == L_DST_FILES) &&
 	    (default_log.fd < 0)) {
 		default_log.fd = open(mainconfig.log_file,
 					    O_WRONLY | O_APPEND | O_CREAT, 0640);
@@ -1068,7 +1068,7 @@ void hup_logfile(void)
 {
 		int fd, old_fd;
 
-		if (default_log.dest != L_DST_FILES) return;
+		if (default_log.dst != L_DST_FILES) return;
 
  		fd = open(mainconfig.log_file,
 			  O_WRONLY | O_APPEND | O_CREAT, 0640);