Allow checking ssl files are readable (check_ssl_files)

- adds a new check_path_exists() method to path_util
- move code checking if SSL-related files exist with assertions (thus
  causing a fatal error) to a new check_ssl_files() method, allowing for
  soft or hard fail modes

This will allow for non-fatal checks of SSL files existence on reload.

Signed-off-by: Loïc Gomez <bip@animanova.fr>

Makefile.am

@@ -3,7 +3,7 @@ if COND_WANT_TESTS
 endif
 SUBDIRS = src . $(MAYBE_TESTS)
 
-dist_man_MANS = bip.1 bip.conf.5 bipmkpw.1
+dist_man_MANS = bip.1 bip.conf.5 bipmkpw.1 bipgenconfig.1
 
 examplesdir = $(prefix)/share/doc/bip/examples/
 dist_examples_DATA = samples/bip.conf samples/bip.vim

bip.conf.5

@@ -146,7 +146,7 @@ Defines the delay between each logfiles sync to the disk. Must be a non null
 positive integer.
 
 .TP
-\fBreconn_timer\fP (default: \fB120\fP)
+\fBreconn_timer\fP (default: \fB30\fP)
 Defines the initial delay (in seconds) before a reconnection attempt.
 The delay increases with the number of attempts:
 delay = reconn_timer * number of attempts
@@ -227,7 +227,7 @@ This option should of course not be enabled if \fBbacklog_lines\fP is 0 !
 If you still want to do so, don't forget to \fB/BIP BLRESET\fP sometimes.
 
 .TP
-\fBbacklog_lines\fP (default: \fB10\fP)
+\fBbacklog_lines\fP (default: \fB0\fP)
 If set to 0, BIP will replay all the logs since last client disconnect. Else,
 it'll replay exactly \fBbacklog_lines\fP lines on each channel and privates.
 Be aware that BIP will replay \fBbacklog_lines\fP lines of all privates, even

configure.ac

@@ -94,6 +94,74 @@ if test "$ap_cv_cc_pie" = "yes"; then
 	enable_pie=yes
 fi
 
+
+AC_CACHE_CHECK([whether $CC accepts hardening flags], [ap_cv_cc_hardening], [
+	save_CFLAGS=$CFLAGS
+	save_LDFLAGS=$LDFLAGS
+	CFLAGS="$CFLAGS -O2 -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fstack-clash-protection -Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -Wl,-z,separate-code"
+	AC_RUN_IFELSE([AC_LANG_SOURCE([[static int foo[30000]; int main () { return 0; }]])],
+		[ap_cv_cc_hardening=yes],
+		[ap_cv_cc_hardening=no],
+		[ap_cv_cc_hardening=yes]
+	)
+	CFLAGS=$save_CFLAGS
+])
+if test "$ap_cv_cc_hardening" = "yes"; then
+	CFLAGS="$CFLAGS -O2 -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fstack-clash-protection -Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -Wl,-z,separate-code"
+	enable_cc_hardening=yes
+fi
+
+AC_CACHE_CHECK([whether $CC accepts some warning flags], [ap_cv_cc_warnings], [
+	save_CFLAGS=$CFLAGS
+	save_LDFLAGS=$LDFLAGS
+	CFLAGS="$CFLAGS -Wformat-overflow=2 -Wformat-truncation=2 -Wtrampolines -Warray-bounds=2 -Wimplicit-fallthrough=3 -Wtraditional-conversion -Wshift-overflow=2 -Wstringop-overflow=4 -Wlogical-op -Wduplicated-cond -Wduplicated-branches -Wformat-signedness -Wstack-usage=1000000 -Wcast-align=strict"
+	AC_RUN_IFELSE([AC_LANG_SOURCE([[static int foo[30000]; int main () { return 0; }]])],
+		[ap_cv_cc_warnings=yes],
+		[ap_cv_cc_warnings=no],
+		[ap_cv_cc_warnings=yes]
+	)
+	CFLAGS=$save_CFLAGS
+])
+if test "$ap_cv_cc_warnings" = "yes"; then
+	CFLAGS="$CFLAGS -Wformat-overflow=2 -Wformat-truncation=2 -Wtrampolines -Warray-bounds=2 -Wimplicit-fallthrough=3 -Wtraditional-conversion -Wshift-overflow=2 -Wstringop-overflow=4 -Wlogical-op -Wduplicated-cond -Wduplicated-branches -Wformat-signedness -Wstack-usage=1000000 -Wcast-align=strict"
+	enable_cc_warnings=yes
+fi
+
+AC_CACHE_CHECK([whether $CC accepts some supplementary warning flags], [ap_cv_cc_warnings2], [
+	save_CFLAGS=$CFLAGS
+	save_LDFLAGS=$LDFLAGS
+	CFLAGS="$CFLAGS -Wformat=2 -Wformat-security -Wnull-dereference -Wstack-protector -Walloca -Wvla -Wcast-qual -Wconversion -Wshadow -Wstrict-overflow=4 -Wstrict-prototypes -Wswitch-default -Wswitch-enum"
+	AC_RUN_IFELSE([AC_LANG_SOURCE([[static int foo[30000]; int main () { return 0; }]])],
+		[ap_cv_cc_warnings2=yes],
+		[ap_cv_cc_warnings2=no],
+		[ap_cv_cc_warnings2=yes]
+	)
+	CFLAGS=$save_CFLAGS
+])
+if test "$ap_cv_cc_warnings2" = "yes"; then
+	CFLAGS="$CFLAGS -Wformat=2 -Wformat-security -Wnull-dereference -Wstack-protector -Walloca -Wvla -Wcast-qual -Wconversion -Wshadow -Wstrict-overflow=4 -Wstrict-prototypes -Wswitch-default -Wswitch-enum"
+	enable_cc_warnings2=yes
+fi
+
+
+
+AC_CACHE_CHECK([whether $CC accepts -Warith-conversion flag], [ap_cv_cc_warith], [
+	save_CFLAGS=$CFLAGS
+	save_LDFLAGS=$LDFLAGS
+	CFLAGS="$CFLAGS -Warith-conversion"
+	AC_RUN_IFELSE([AC_LANG_SOURCE([[static int foo[30000]; int main () { return 0; }]])],
+		[ap_cv_cc_warith=yes],
+		[ap_cv_cc_warith=no],
+		[ap_cv_cc_warith=yes]
+	)
+	CFLAGS=$save_CFLAGS
+])
+if test "$ap_cv_cc_warith" = "yes"; then
+	CFLAGS="$CFLAGS -Warith-conversion"
+	enable_warith_conversion=yes
+fi
+
+
 PKG_CHECK_MODULES([CHECK], [check >= 0.9.6], [enable_tests=yes], [enable_tests=no])
 AM_CONDITIONAL([COND_WANT_TESTS], [test "$enable_tests" = yes])
 

samples/bip.conf

@@ -86,7 +86,7 @@
 # Sets the initial delay (in seconds) before a reconnection attempt.
 # The delay increases with the number of attempts:
 # delay = reconn_timer * number of attempts
-#reconn_timer = 120;
+#reconn_timer = 30;
 
 # Network definition, a name and server info
 #network {

scripts/bipgenconfig

@@ -119,7 +119,7 @@ my %optdesc = (
 			'optional' => 1,
 			'depends' => 'log', 'depval' => 'true',
 			'desc' => 'Do you want to activate backlog {play back logs} system ?' },
-		'backlog_lines' => { 'type' => 'i', 'adv' => 0, 'default' => '10',
+		'backlog_lines' => { 'type' => 'i', 'adv' => 0, 'default' => '0',
 			'optional' => 1,
 			'depends' => 'backlog', 'depval' => 'true',
 			'desc' => 'How much line do you want bip to play back upon client connect' .

src/Makefile.am

@@ -36,9 +36,4 @@ bipmkpw_LDADD = libbip.a libbiplex.a $(OPENSSL_LIBS)
 AM_YFLAGS= -d
 BUILT_SOURCES = conf.c conf.h lex.c
 
-AM_CFLAGS=-Wall -Wextra -Werror \
-	-O2 \
-	-D_FORTIFY_SOURCE=2 \
-	-fstack-protector-strong -fstack-clash-protection \
-	-Wl,-z,relro -Wl,-z,now -Wl,-z,noexecstack -Wl,-z,separate-code \
-	-Wpedantic -Wformat=2 -Wformat-overflow=2 -Wformat-truncation=2 -Wformat-security -Wnull-dereference -Wstack-protector -Wtrampolines -Walloca -Wvla -Warray-bounds=2 -Wimplicit-fallthrough=3 -Wtraditional-conversion -Wshift-overflow=2 -Wcast-qual -Wstringop-overflow=4 -Wconversion -Warith-conversion -Wlogical-op -Wduplicated-cond -Wduplicated-branches -Wformat-signedness -Wshadow -Wstrict-overflow=4 -Wundef -Wstrict-prototypes -Wswitch-default -Wswitch-enum -Wstack-usage=1000000 -Wcast-align=strict
+AM_CFLAGS=-Wall -Wextra -Werror -Wundef -Wpedantic

src/bip.c

@@ -67,6 +67,7 @@ void conf_die(bip_t *bip, char *fmt, ...);
 static char *get_tuple_pvalue(list_t *tuple_l, int lex);
 void bip_notify(struct link_client *ic, char *fmt, ...);
 void adm_list_connections(struct link_client *ic, struct bipuser *bu);
+struct link *find_link(const char *link_name, struct bipuser *bu);
 void free_conf(list_t *l);
 
 
@@ -373,6 +374,45 @@ static int add_network(bip_t *bip, list_t *data)
 	return 1;
 }
 
+void adm_bip_jump(struct link_client *ic, const char *conn_name,
+		  int reset_timer)
+{
+	struct link *lnk;
+	if (conn_name) {
+		lnk = find_link(conn_name, LINK(ic)->user);
+		if (!lnk) {
+			bip_notify(ic, "-- Cannot find connection named %s",
+				   conn_name);
+			return;
+		}
+		goto do_the_jump;
+	} else {
+		lnk = LINK(ic);
+	}
+
+do_the_jump:
+	if (!lnk->l_server) {
+		if (reset_timer) {
+			lnk->recon_timer = 0;
+			bip_notify(ic,
+				   "-- %s is not connected, "
+				   "timer has been reset, please wait",
+				   conn_name);
+			return;
+		}
+		int timer = (lnk->recon_timer ? lnk->recon_timer : 0);
+		bip_notify(ic,
+			   "-- %s is not connected, "
+			   "please wait for reconnect (%ds)",
+			   conn_name, timer);
+		return;
+	}
+
+	WRITE_LINE1(CONN(lnk->l_server), NULL, "QUIT", "jumpin' jumpin'");
+	connection_close(CONN(lnk->l_server));
+	bip_notify(ic, "-- Jumping to next server on %s", conn_name);
+}
+
 void adm_bip_delconn(bip_t *bip, struct link_client *ic, const char *conn_name)
 {
 	struct bipuser *user = LINK(ic)->user;
@@ -664,6 +704,31 @@ static int add_connection(bip_t *bip, struct bipuser *user, list_t *data)
 	return 1;
 }
 
+struct link *find_link(const char *link_name, struct bipuser *bu)
+{
+	list_iterator_t it;
+
+	// Immediately return NULL when bip user (bu) is NULL
+	if (!bu) {
+		return NULL;
+	}
+
+	for (list_it_init(&_bip->link_list, &it); list_it_item(&it);
+	     list_it_next(&it)) {
+		struct link *lnk = list_it_item(&it);
+		if (!lnk)
+			continue;
+		// Only lookup in optionally specified user links
+		if (bu != lnk->user)
+			continue;
+
+		if (strcmp(link_name, lnk->name) == 0)
+			return lnk;
+	}
+
+	return NULL;
+}
+
 static char *get_tuple_pvalue(list_t *tuple_l, int lex)
 {
 	struct tuple *t;
@@ -1331,9 +1396,10 @@ void adm_print_connection(struct link_client *ic, struct link *lnk,
 	bufpos = buf;
 
 	list_iterator_t itocs;
+	int i = 0;
 	for (list_it_init(&lnk->on_connect_send, &itocs);
-	     list_it_item(&itocs);) {
-		bufpos = bip_strcatf_fit(&remaining, bufpos, "%s",
+		 list_it_item(&itocs) && i < 10; i++) {
+		bufpos = bip_strcatf_fit(&remaining, bufpos, "    on_connect_send: %s",
 					 (char *)list_it_item(&itocs));
 		if (!bufpos) {
 			// if oversized, print and reset
@@ -1341,6 +1407,7 @@ void adm_print_connection(struct link_client *ic, struct link *lnk,
 			bip_notify(ic, "%s", buf);
 			remaining = LINE_SIZE_LIM;
 			bufpos = buf;
+			list_it_next(&itocs);
 			continue;
 		} else {
 			// if ok, go to next item
@@ -1992,8 +2059,8 @@ void adm_bip_help(struct link_client *ic, int admin, const char *subhelp)
 			bip_notify(ic, "/BIP LIST networks|connections");
 		}
 		bip_notify(ic,
-			   "/BIP JUMP # jump to next server (in same "
-			   "network)");
+			   "/BIP JUMP [-f] [conn_name] # jump to next "
+			   "server (defaults to current network)");
 		bip_notify(ic,
 			   "/BIP BLRESET [channel|query]# reset backlog "
 			   "(this connection only). Add -q flag and the "
@@ -2046,8 +2113,14 @@ void adm_bip_help(struct link_client *ic, int admin, const char *subhelp)
 			   "  Removing a connection will cause "
 			   "its disconnection.");
 	} else if (strcasecmp(subhelp, "JUMP") == 0) {
-		bip_notify(ic, "/BIP JUMP :");
+		bip_notify(ic, "/BIP JUMP [-f] [conn_name]:");
 		bip_notify(ic, "  Jump to next server in current network.");
+		bip_notify(ic,
+			   "  If [conn_name] is set, jump to next server in "
+			   "[conn_name] network instead.");
+		bip_notify(ic,
+			   "  If [-f] flag is used, also resets reconnect "
+			   "timer.");
 	} else if (strcasecmp(subhelp, "BLRESET") == 0) {
 		bip_notify(ic, "/BIP BLRESET :");
 		bip_notify(ic, "  Reset backlog on this network.");
@@ -2227,12 +2300,16 @@ int adm_bip(bip_t *bip, struct link_client *ic, struct line *line, int privmsg)
 			bip_notify(ic, "-- Invalid INFO request");
 		}
 	} else if (irc_line_elem_case_equals(line, privmsg + 1, "JUMP")) {
-		if (LINK(ic)->l_server) {
-			WRITE_LINE1(CONN(LINK(ic)->l_server), NULL, "QUIT",
-				    "jumpin' jumpin'");
-			connection_close(CONN(LINK(ic)->l_server));
+		if (irc_line_count(line) == privmsg + 2) {
+			adm_bip_jump(ic, NULL, 0);
+		} else if (irc_line_count(line) == privmsg + 3) {
+			adm_bip_jump(ic, irc_line_elem(line, privmsg + 2), 0);
+		} else if (irc_line_count(line) == privmsg + 4
+			   && irc_line_elem_equals(line, privmsg + 2, "-f")) {
+			adm_bip_jump(ic, irc_line_elem(line, privmsg + 3), 1);
+		} else {
+			bip_notify(ic, "-- Invalid usage (/BIP HELP JUMP)");
 		}
-		bip_notify(ic, "-- Jumping to next server");
 	} else if (irc_line_elem_case_equals(line, privmsg + 1, "BLRESET")) {
 		if (irc_line_includes(line, privmsg + 2)) {
 			if (irc_line_elem_equals(line, privmsg + 2, "-q")) {

src/bip_main.c

@@ -68,6 +68,7 @@ void rlimit_cpu_reached(int i);
 void rlimit_bigfile_reached(int i);
 void conf_die(bip_t *bip, char *fmt, ...);
 int fireup(bip_t *bip, FILE *conf);
+int check_ssl_files(int failmode);
 int do_pid_stuff(void);
 
 static void usage(char *name)
@@ -143,6 +144,44 @@ static pid_t daemonize(void)
 	return getpid();
 }
 
+int check_ssl_files(int failmode)
+{
+	int e;
+	struct stat fs;
+
+	if (!conf_ssl_certfile) {
+		conf_ssl_certfile = default_path(
+			conf_biphome, "bip.pem", "SSL certificate");
+	}
+
+	if (failmode == HARD_FAIL)
+		assert_path_exists(conf_ssl_certfile);
+	else if (!check_path_exists(conf_ssl_certfile))
+		return 0;
+
+	e = stat(conf_ssl_certfile, &fs);
+	if (e)
+		mylog(LOG_WARN,
+			  "Unable to check PEM file, stat(%s): %s",
+			  conf_ssl_certfile, strerror(errno));
+	else if ((fs.st_mode & S_IROTH) | (fs.st_mode & S_IWOTH))
+		mylog(LOG_ERROR,
+			  "PEM file %s should not be world "
+			  "readable / writable. Please fix the modes.",
+			  conf_ssl_certfile);
+
+	if (conf_client_dh_file) {
+		if (failmode == HARD_FAIL) {
+			assert_path_exists(conf_client_dh_file);
+		} else if (!check_path_exists(conf_client_dh_file)) {
+			return 0;
+		}
+	}
+
+	/* all is well */
+	return 1;
+}
+
 int main(int argc, char **argv)
 {
 	FILE *conf = NULL;
@@ -264,31 +303,8 @@ int main(int argc, char **argv)
 
 #ifdef HAVE_LIBSSL
 	if (conf_css) {
-		int e;
-		struct stat fs;
-
-		if (!conf_ssl_certfile) {
-			conf_ssl_certfile = default_path(
-				conf_biphome, "bip.pem", "SSL certificate");
-		}
-		assert_path_exists(conf_ssl_certfile);
-
-		e = stat(conf_ssl_certfile, &fs);
-		if (e)
-			mylog(LOG_WARN,
-			      "Unable to check PEM file, stat(%s): "
-			      "%s",
-			      conf_ssl_certfile, strerror(errno));
-		else if ((fs.st_mode & S_IROTH) | (fs.st_mode & S_IWOTH))
-			mylog(LOG_ERROR,
-			      "PEM file %s should not be world "
-			      "readable / writable. Please fix the modes.",
-			      conf_ssl_certfile);
-
-		if (conf_client_dh_file) {
-			assert_path_exists(conf_client_dh_file);
-		}
-	}
+        check_ssl_files(HARD_FAIL);
+    }
 #endif
 
 	check_dir(conf_log_root, 1);

src/bipmkpw.c

@@ -23,9 +23,9 @@
 #include "util.h"
 #include "md5.h"
 
-int conf_log_level;
-FILE *conf_global_log_file;
-int conf_log_system;
+extern int conf_log_level;
+extern FILE *conf_global_log_file;
+extern int conf_log_system;
 
 void bipmkpw_fatal(char *msg, char *err)
 {

src/connection.c

@@ -62,7 +62,7 @@ void connection_close(connection_t *cn)
 {
 	mylog(LOG_DEBUG, "Connection close asked. FD:%d (status: %d)",
 	      (long)cn->handle, cn->connected);
-	if (cn->connected != CONN_DISCONN && cn->connected != CONN_ERROR) {
+	if (cn->connected != CONN_DISCONN) {
 		cn->connected = CONN_DISCONN;
 		if (close(cn->handle) == -1)
 			mylog(LOG_WARN, "Error on socket close: %s",
@@ -1171,6 +1171,7 @@ static connection_t *connection_init(int anti_flood, int ssl, time_t timeout,
 static int ctx_set_dh(SSL_CTX *ctx)
 {
 	/* Return ephemeral DH parameters. */
+#if OPENSSL_VERSION_NUMBER < 0x30000000L /* 3.0.0 */
 	DH *dh = NULL;
 	FILE *f;
 	long ret;
@@ -1203,7 +1204,31 @@ static int ctx_set_dh(SSL_CTX *ctx)
 		      ERR_error_string(ERR_get_error(), NULL));
 		return 0;
 	}
+#else
+    BIO *pbio = BIO_new_file(conf_client_dh_file, "r");
+    if (!pbio) {
+	    mylog(LOG_ERROR, "Unable to open DH parameters, BIO_new_file(%s): %s",
+                conf_client_dh_file, ERR_error_string(ERR_get_error(), NULL));
+        return 0;
+    }
 
+    EVP_PKEY *param = PEM_read_bio_Parameters(pbio, NULL);
+    BIO_free(pbio);
+    if (!param) {
+	    mylog(LOG_ERROR, "TLS DH Error: PEM_read_bio_Parameters(%s): %s",
+                conf_client_dh_file, ERR_error_string(ERR_get_error(), NULL));
+        return 0;
+    }
+
+    if (SSL_CTX_set0_tmp_dh_pkey(ctx, param) != 1) {
+        EVP_PKEY_free(param);
+	    mylog(LOG_ERROR, "TLS DH Error: SSL_CTX_set0_tmp_dh_pkey(%s): %s",
+                conf_client_dh_file, ERR_error_string(ERR_get_error(), NULL));
+        return 0;
+    }
+#endif
+	mylog(LOG_DEBUG, "TLS: succesfully set up DH params %s",
+            conf_client_dh_file);
 	return 1;
 }
 #endif

src/defaults.h

@@ -19,7 +19,7 @@
 #define DEFAULT_BACKLOG 1
 #define DEFAULT_ALWAYS_BACKLOG 0
 #define DEFAULT_BL_MSG_ONLY 0
-#define DEFAULT_BACKLOG_LINES 10
+#define DEFAULT_BACKLOG_LINES 0
 #define DEFAULT_BACKLOG_TIMESTAMP BLTSTime
 #define DEFAULT_BLRESET_ON_TALK 0
 #define DEFAULT_BLRESET_CONNECTION 0
@@ -29,6 +29,6 @@
 #define DEFAULT_LOG_LEVEL LOG_INFO
 #define DEFAULT_LOG_FORMAT "%u/%n/%Y-%m/%c.%d.log"
 #define DEFAULT_BIP_USE_NOTICE 0
-#define DEFAULT_RECONN_TIMER 120
+#define DEFAULT_RECONN_TIMER 30
 
 #endif /* DEFAULTS_H */

src/irc.c

@@ -33,6 +33,7 @@
 extern int sighup;
 extern bip_t *_bip;
 
+static int irc_generic_error(struct link_server *server, struct line *line);
 static int irc_join(struct link_server *server, struct line *line);
 static int irc_part(struct link_server *server, struct line *line);
 static int irc_mode(struct link_server *server, struct line *line);
@@ -625,6 +626,10 @@ int irc_dispatch_server(bip_t *bip, struct link_server *server,
 		ret = irc_quit(server, line);
 	} else if (irc_line_elem_equals(line, 0, "NICK")) {
 		ret = irc_nick(server, line);
+	} else if (irc_line_is_error(line)) {
+		// IRC errors catchall (for unhandled ones)
+		// logs error to bip.log
+		ret = irc_generic_error(server, line);
 	}
 
 	if (ret == OK_COPY) {
@@ -1025,6 +1030,31 @@ static int irc_cli_pass(bip_t *bip, struct link_client *ic, struct line *line)
 	return OK_FORGET;
 }
 
+static int irc_cli_cap(bip_t *bip, struct link_client *ic, struct line *line)
+{
+	if (irc_line_count(line) < 2)
+		return ERR_PROTOCOL;
+
+	/* When we decide to enable actual capabilities, we'll have to handle CAP
+	 * version, add a flag cap_started or similar, and handle CAP END.
+	 */
+	if (irc_line_elem_equals(line, 1, "LS")) {
+		WRITE_LINE2(CONN(ic), NULL, "CAP", "*", "LS");
+	} else if (irc_line_elem_equals(line, 1, "LIST")) {
+		WRITE_LINE3(CONN(ic), NULL, "CAP", "*", "LIST", "");
+	} else if (irc_line_elem_equals(line, 1, "REQ")) {
+		char *caps = irc_line_to_string_skip(line, 2);
+		if (caps) {
+			caps++;
+			WRITE_LINE3(CONN(ic), NULL, "CAP", "*", "NAK", caps);
+		}
+	}
+
+	if ((ic->state & IRCC_READY) == IRCC_READY)
+		return irc_cli_startup(bip, ic, line);
+	return OK_FORGET;
+}
+
 static int irc_cli_quit(struct link_client *ic, struct line *line)
 {
 	(void)ic;
@@ -1403,6 +1433,8 @@ static int irc_dispatch_logging_client(bip_t *bip, struct link_client *ic,
 		return irc_cli_user(bip, ic, line);
 	} else if (irc_line_elem_equals(line, 0, "PASS")) {
 		return irc_cli_pass(bip, ic, line);
+	} else if (irc_line_elem_equals(line, 0, "CAP")) {
+		return irc_cli_cap(bip, ic, line);
 	}
 	return OK_FORGET;
 }
@@ -1448,6 +1480,17 @@ static int origin_is_me(struct line *l, struct link_server *server)
 	return 0;
 }
 
+static int irc_generic_error(struct link_server *server, struct line *line)
+{
+	if (irc_line_count(line) == 4)
+		mylog(LOG_INFO, "[%s] IRC error: %s", LINK(server)->name,
+			irc_line_elem(line, 3));
+	else
+		mylog(LOG_INFO, "[%s] IRC error: %s", LINK(server)->name,
+			irc_line_to_string(line));
+	return OK_COPY;
+}
+
 static int irc_join(struct link_server *server, struct line *line)
 {
 	char *s_nick;

src/line.c

@@ -16,6 +16,8 @@
 #include "line.h"
 #include "util.h"
 
+char *_irc_line_to_string(struct line *l, int skip_first);
+
 // TODO resolve assuming signed overflow does not occur when changing X +- C1
 // cmp C2 to X cmp C2 -+ C1
 #pragma GCC diagnostic ignored "-Wstrict-overflow"
@@ -76,6 +78,19 @@ void irc_line_append(struct line *l, const char *s)
 }
 
 char *irc_line_to_string(struct line *l)
+{
+    return _irc_line_to_string(l, 0);
+}
+
+char *irc_line_to_string_skip(struct line *l, int skip_first)
+{
+    if (skip_first >= irc_line_count(l)) {
+        return NULL;
+    }
+    return _irc_line_to_string(l, skip_first);
+}
+
+char *_irc_line_to_string(struct line *l, int skip_first)
 {
 	size_t len = 0;
 	int i;
@@ -83,7 +98,7 @@ char *irc_line_to_string(struct line *l)
 
 	if (l->origin)
 		len = strlen(l->origin) + 2;
-	for (i = 0; i < array_count(&l->words); i++)
+	for (i = skip_first; i < array_count(&l->words); i++)
 		len += strlen(array_get(&l->words, i)) + 1;
 	len += 1; /* remove one trailing space and add \r\n */
 	len++;	  /* last args ":" */
@@ -95,7 +110,7 @@ char *irc_line_to_string(struct line *l)
 		strcat(ret, l->origin);
 		strcat(ret, " ");
 	}
-	for (i = 0; i < array_count(&l->words) - 1; i++) {
+	for (i = skip_first; i < array_count(&l->words) - 1; i++) {
 		strcat(ret, array_get(&l->words, i));
 		strcat(ret, " ");
 	}
@@ -143,6 +158,12 @@ void irc_line_drop(struct line *line, int elem)
 	bip_cfree(array_drop(&line->words, elem));
 }
 
+int irc_line_is_error(struct line *line)
+{
+	const char *irc_code = irc_line_elem(line, 0);
+	return (irc_code[0] == '4');
+}
+
 int irc_line_elem_equals(struct line *line, int elem, const char *cmp)
 {
 	return !strcmp(irc_line_elem(line, elem), cmp);

src/line.h

@@ -90,6 +90,7 @@ void irc_line_write(struct line *l, connection_t *c);
 void irc_line_append(struct line *l, const char *s);
 struct line *irc_line_new_from_string(char *str);
 char *irc_line_to_string(struct line *l);
+char *irc_line_to_string_skip(struct line *l, int skip_first);
 char *irc_line_to_string_to(struct line *line, char *nick);
 void irc_line_free(struct line *l);
 struct line *irc_line_dup(struct line *line);
@@ -98,6 +99,7 @@ int irc_line_includes(struct line *line, int elem);
 const char *irc_line_elem(struct line *line, int elem);
 int irc_line_count(struct line *line);
 char *irc_line_pop(struct line *l);
+int irc_line_is_error(struct line *line);
 int irc_line_elem_equals(struct line *line, int elem, const char *cmp);
 int irc_line_elem_case_equals(struct line *line, int elem, const char *cmp);
 void irc_line_drop(struct line *line, int elem);

src/path_util.c

@@ -35,3 +35,15 @@ void assert_path_exists(char *path)
 	if (stat(path, &st_buf) != 0)
 		fatal("Path %s doesn't exist (%s)", path, strerror(errno));
 }
+
+int check_path_exists(char *path)
+{
+	struct stat st_buf;
+
+	if (stat(path, &st_buf) != 0) {
+		mylog(LOG_WARN, "Path %s doesn't exist (%s)", path, strerror(errno));
+        return 0;
+    } else {
+        return 1;
+    }
+}

src/path_util.h

@@ -18,5 +18,7 @@
 char *default_path(const char *biphome, const char *filename, const char *desc);
 /* exit program if path doesn't exist */
 void assert_path_exists(char *path);
+/* return 1 if path exists, 0 otherwise */
+int check_path_exists(char *path);
 
 #endif