From ce1b254834788eca7546b8f720cdabdeb0f6fe8f Mon Sep 17 00:00:00 2001
From: Reiner Herrmann <reiner@reiner-h.de>
Date: Sat, 8 Aug 2020 14:26:57 +0200
Subject: annotate some functions as non-returning (#3574)

---
 src/firejail/arp.c      |  4 +---
 src/firejail/firejail.h | 35 +++++++++++++++++------------------
 src/firejail/join.c     |  2 +-
 src/firejail/main.c     |  3 +--
 src/firejail/protocol.c |  2 +-
 src/firejail/sbox.c     |  2 +-
 src/firejail/x11.c      |  4 ++--
 src/firemon/firemon.h   |  6 +++---
 src/firemon/procevent.c | 13 +++++--------
 src/include/syscall.h   |  2 +-
 src/lib/errno.c         |  2 +-
 11 files changed, 34 insertions(+), 41 deletions(-)

(limited to 'src')

diff --git a/src/firejail/arp.c b/src/firejail/arp.c
index 3714af9a3..f88d0a1dd 100644
--- a/src/firejail/arp.c
+++ b/src/firejail/arp.c
@@ -239,9 +239,7 @@ int arp_check(const char *dev, uint32_t destaddr) {
 		}
 	}
 
-	// it will never get here!
-	close(sock);
-	return -1;
+	__builtin_unreachable();
 }
 
 // assign a random IP address and check it
diff --git a/src/firejail/firejail.h b/src/firejail/firejail.h
index 54a1023ab..9c5a050b4 100644
--- a/src/firejail/firejail.h
+++ b/src/firejail/firejail.h
@@ -371,14 +371,14 @@ char *guess_shell(void);
 
 // sandbox.c
 int sandbox(void* sandbox_arg);
-void start_application(int no_sandbox, FILE *fp);
+void start_application(int no_sandbox, FILE *fp) __attribute__((noreturn));
 void set_apparmor(void);
 
 // network_main.c
 void net_configure_sandbox_ip(Bridge *br);
 void net_configure_veth_pair(Bridge *br, const char *ifname, pid_t child);
 void net_check_cfg(void);
-void net_dns_print(pid_t pid);
+void net_dns_print(pid_t pid) __attribute__((noreturn));
 void network_main(pid_t child);
 void net_print(pid_t pid);
 
@@ -453,13 +453,12 @@ void profile_add_ignore(const char *str);
 void list(void);
 void tree(void);
 void top(void);
-void netstats(void);
 
 // usage.c
 void usage(void);
 
 // join.c
-void join(pid_t pid, int argc, char **argv, int index);
+void join(pid_t pid, int argc, char **argv, int index) __attribute__((noreturn));
 bool is_ready_for_join(const pid_t pid);
 void check_join_permission(pid_t pid);
 pid_t switch_to_child(pid_t pid);
@@ -486,7 +485,7 @@ int macro_id(const char *name);
 
 
 // util.c
-void errLogExit(char* fmt, ...);
+void errLogExit(char* fmt, ...) __attribute__((noreturn));
 void fwarning(char* fmt, ...);
 void fmessage(char* fmt, ...);
 void drop_privs(int nogroups);
@@ -584,7 +583,7 @@ int seccomp_load(const char *fname);
 int seccomp_filter_drop(bool native);
 int seccomp_filter_keep(bool native);
 int seccomp_filter_mdwx(bool native);
-void seccomp_print_filter(pid_t pid);
+void seccomp_print_filter(pid_t pid) __attribute__((noreturn));
 
 // caps.c
 void seccomp_load_file_list(void);
@@ -595,7 +594,7 @@ void caps_set(uint64_t caps);
 void caps_check_list(const char *clist, void (*callback)(int));
 void caps_drop_list(const char *clist);
 void caps_keep_list(const char *clist);
-void caps_print_filter(pid_t pid);
+void caps_print_filter(pid_t pid) __attribute__((noreturn));
 void caps_drop_dac_override(void);
 
 // fs_trace.c
@@ -618,7 +617,7 @@ void read_cpu_list(const char *str);
 void set_cpu_affinity(void);
 void load_cpu(const char *fname);
 void save_cpu(void);
-void cpu_print_filter(pid_t pid);
+void cpu_print_filter(pid_t pid) __attribute__((noreturn));
 
 // cgroup.c
 void save_cgroup(void);
@@ -640,7 +639,7 @@ void netns(const char *nsname);
 void netns_mounts(const char *nsname);
 
 // bandwidth.c
-void bandwidth_pid(pid_t pid, const char *command, const char *dev, int down, int up);
+void bandwidth_pid(pid_t pid, const char *command, const char *dev, int down, int up) __attribute__((noreturn));
 void network_set_run_file(pid_t pid);
 
 // fs_etc.c
@@ -650,7 +649,7 @@ void fs_private_dir_list(const char *private_dir, const char *private_run_dir, c
 // no_sandbox.c
 int check_namespace_virt(void);
 int check_kernel_procs(void);
-void run_no_sandbox(int argc, char **argv);
+void run_no_sandbox(int argc, char **argv) __attribute__((noreturn));
 
 #define MAX_ENVS 256			// some sane maximum number of environment variables
 #define MAX_ENV_LEN (PATH_MAX + 32)	// FOOBAR=SOME_PATH
@@ -681,7 +680,7 @@ void fs_private_lib(void);
 // protocol.c
 void protocol_filter_save(void);
 void protocol_filter_load(const char *fname);
-void protocol_print_filter(pid_t pid);
+void protocol_print_filter(pid_t pid) __attribute__((noreturn));
 
 // restrict_users.c
 void restrict_users(void);
@@ -693,7 +692,7 @@ void fs_logger2int(const char *msg1, int d);
 void fs_logger3(const char *msg1, const char *msg2, const char *msg3);
 void fs_logger_print(void);
 void fs_logger_change_owner(void);
-void fs_logger_print_log(pid_t pid);
+void fs_logger_print_log(pid_t pid) __attribute__((noreturn));
 
 // run_symlink.c
 void run_symlink(int argc, char **argv, int run_as_is);
@@ -719,11 +718,11 @@ void fs_mkfile(const char *name);
 
 void fs_x11(void);
 int x11_display(void);
-void x11_start(int argc, char **argv);
-void x11_start_xpra(int argc, char **argv);
-void x11_start_xephyr(int argc, char **argv);
+void x11_start(int argc, char **argv) __attribute__((noreturn));
+void x11_start_xpra(int argc, char **argv) __attribute__((noreturn));
+void x11_start_xephyr(int argc, char **argv) __attribute__((noreturn));
 void x11_block(void);
-void x11_start_xvfb(int argc, char **argv);
+void x11_start_xvfb(int argc, char **argv) __attribute__((noreturn));
 void x11_xorg(void);
 
 // ls.c
@@ -733,7 +732,7 @@ enum {
 	SANDBOX_FS_PUT,
 	SANDBOX_FS_MAX // this should always be the last entry
 };
-void sandboxfs(int op, pid_t pid, const char *path1, const char *path2);
+void sandboxfs(int op, pid_t pid, const char *path1, const char *path2) __attribute__((noreturn));
 
 // checkcfg.c
 #define DEFAULT_ARP_PROBES 2
@@ -839,7 +838,7 @@ void build_appimage_cmdline(char **command_line, char **window_title, int argc,
 // run sbox
 int sbox_run(unsigned filter, int num, ...);
 int sbox_run_v(unsigned filter, char * const arg[]);
-void sbox_exec_v(unsigned filter, char * const arg[]);
+void sbox_exec_v(unsigned filter, char * const arg[]) __attribute__((noreturn));
 
 // run_files.c
 void delete_run_files(pid_t pid);
diff --git a/src/firejail/join.c b/src/firejail/join.c
index 4c8555f29..f202d1a9c 100644
--- a/src/firejail/join.c
+++ b/src/firejail/join.c
@@ -588,7 +588,7 @@ void join(pid_t pid, int argc, char **argv, int index) {
 
 		start_application(0, NULL);
 
-		// it will never get here!!!
+		__builtin_unreachable();
 	}
 	EUID_USER();
 
diff --git a/src/firejail/main.c b/src/firejail/main.c
index 79e39b669..f37d1ca52 100644
--- a/src/firejail/main.c
+++ b/src/firejail/main.c
@@ -1159,8 +1159,7 @@ int main(int argc, char **argv, char **envp) {
 
 			// start the program directly without sandboxing
 			run_no_sandbox(argc, argv);
-			// it will never get here!
-			assert(0);
+			__builtin_unreachable();
 		}
 	}
 	EUID_ASSERT();
diff --git a/src/firejail/protocol.c b/src/firejail/protocol.c
index 6402afbc6..a1594d6b9 100644
--- a/src/firejail/protocol.c
+++ b/src/firejail/protocol.c
@@ -90,7 +90,7 @@ void protocol_print_filter(pid_t pid) {
 	exit(0);
 #else
 	fwarning("--protocol not supported on this platform\n");
-	return;
+	exit(1);
 #endif
 }
 
diff --git a/src/firejail/sbox.c b/src/firejail/sbox.c
index 99f11a246..57c21ce78 100644
--- a/src/firejail/sbox.c
+++ b/src/firejail/sbox.c
@@ -31,7 +31,7 @@
 #define O_PATH 010000000
 #endif
 
-static int sbox_do_exec_v(unsigned filtermask, char * const arg[]) {
+static int __attribute__((noreturn)) sbox_do_exec_v(unsigned filtermask, char * const arg[]) {
 	// build a new, clean environment
 	int env_index = 0;
 	char *new_environment[256] = { NULL };
diff --git a/src/firejail/x11.c b/src/firejail/x11.c
index 98ac184d9..ba54ca376 100644
--- a/src/firejail/x11.c
+++ b/src/firejail/x11.c
@@ -682,7 +682,7 @@ static char * get_title_arg_str() {
 }
 
 
-void x11_start_xpra_old(int argc, char **argv, int display, char *display_str) {
+static void __attribute__((noreturn)) x11_start_xpra_old(int argc, char **argv, int display, char *display_str) {
 	EUID_ASSERT();
 	int i;
 	struct stat s;
@@ -921,7 +921,7 @@ void x11_start_xpra_old(int argc, char **argv, int display, char *display_str) {
 }
 
 
-void x11_start_xpra_new(int argc, char **argv, char *display_str) {
+static void __attribute__((noreturn)) x11_start_xpra_new(int argc, char **argv, char *display_str) {
 	EUID_ASSERT();
 	int i;
 	pid_t server = 0;
diff --git a/src/firemon/firemon.h b/src/firemon/firemon.h
index 7a55a64fb..3fba486eb 100644
--- a/src/firemon/firemon.h
+++ b/src/firemon/firemon.h
@@ -46,13 +46,13 @@ void firemon_sleep(int st);
 
 
 // procevent.c
-void procevent(pid_t pid);
+void procevent(pid_t pid) __attribute__((noreturn));
 
 // usage.c
 void usage(void);
 
 // top.c
-void top(void);
+void top(void) __attribute__((noreturn));
 
 // list.c
 void list(void);
@@ -82,7 +82,7 @@ void cgroup(pid_t pid, int print_procs);
 void tree(pid_t pid);
 
 // netstats.c
-void netstats(void);
+void netstats(void) __attribute__((noreturn));
 
 // x11.c
 void x11(pid_t pid, int print_procs);
diff --git a/src/firemon/procevent.c b/src/firemon/procevent.c
index 7dd08444e..45964d3a2 100644
--- a/src/firemon/procevent.c
+++ b/src/firemon/procevent.c
@@ -220,7 +220,7 @@ errexit:
 }
 
 
-static int procevent_monitor(const int sock, pid_t mypid) {
+static void __attribute__((noreturn)) procevent_monitor(const int sock, pid_t mypid) {
 	ssize_t len;
 	struct nlmsghdr *nlmsghdr;
 
@@ -246,8 +246,7 @@ static int procevent_monitor(const int sock, pid_t mypid) {
 
 		int rv = select(max, &readfds, NULL, NULL, &tv);
 		if (rv == -1) {
-			fprintf(stderr, "recv: %s\n", strerror(errno));
-			return -1;
+			errExit("recv");
 		}
 
 		// timeout
@@ -259,7 +258,7 @@ static int procevent_monitor(const int sock, pid_t mypid) {
 
 
 		if ((len = recv(sock, buf, sizeof(buf), 0)) == 0)
-			return 0;
+			exit(0);
 		if (len == -1) {
 			if (errno == EINTR)
 				continue;
@@ -271,7 +270,7 @@ static int procevent_monitor(const int sock, pid_t mypid) {
 			}
 			else {
 				fprintf(stderr,"Error: rx socket recv call, errno %d, %s\n", errno, strerror(errno));
-				return -1;
+				exit(1);
 			}
 		}
 
@@ -497,7 +496,7 @@ static int procevent_monitor(const int sock, pid_t mypid) {
 				exit(0);
 		}
 	}
-	return 0;
+	__builtin_unreachable();
 }
 
 void procevent(pid_t pid) {
@@ -515,6 +514,4 @@ void procevent(pid_t pid) {
 	}
 
 	procevent_monitor(sock, pid); // it will never return from here
-	assert(0);
-	close(sock); // quiet static analyzers
 }
diff --git a/src/include/syscall.h b/src/include/syscall.h
index 89b54170e..489da0600 100644
--- a/src/include/syscall.h
+++ b/src/include/syscall.h
@@ -32,7 +32,7 @@ void filter_add_blacklist_override(int fd, int syscall, int arg, void *ptrarg, b
 // errno.c
 void errno_print(void);
 int errno_find_name(const char *name);
-char *errno_find_nr(int nr);
+const char *errno_find_nr(int nr);
 
 // syscall.c
 void syscall_print(void);
diff --git a/src/lib/errno.c b/src/lib/errno.c
index d38c197ad..881c3b27e 100644
--- a/src/lib/errno.c
+++ b/src/lib/errno.c
@@ -183,7 +183,7 @@ int errno_find_name(const char *name) {
 	return -1;
 }
 
-char *errno_find_nr(int nr) {
+const char *errno_find_nr(int nr) {
 	int i;
 	int elems = sizeof(errnolist) / sizeof(errnolist[0]);
 	for (i = 0; i < elems; i++) {
-- 
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