executor: warn about C89-style var declarations

We generally use the newer C99 var declarations combined with initialization because:
 - declarations are more local, reduced scope
 - fewer lines of code
 - less potential for using uninit vars and other bugs
However, we have some relic code from times when we did not understand
if we need to stick with C89 or not. Also some external contributions
that don't follow style around.

Add a static check for C89-style declarations and fix existing precedents.

Akaros toolchain uses -std=gnu89 (or something) and does not allow
variable declarations inside of for init statement. And we can't switch
it to -std=c99 because Akaros headers are C89 themselves.
So in common.h we need to declare loop counters outside of for.

1 files changed, 7 insertions, 14 deletions

diff --git a/executor/common_bsd.h b/executor/common_bsd.h
index 2aa651dd3..01eaa522c 100644
--- a/executor/common_bsd.h
+++ b/executor/common_bsd.h
@@ -20,19 +20,17 @@
 #include <dirent.h>
 static void setup_usb(void)
 {
-	struct dirent* ent;
-	char path[1024];
-	DIR* dir;
-
-	dir = opendir("/dev");
+	DIR* dir = opendir("/dev");
 	if (dir == NULL)
 		fail("failed to open /dev");
 
+	struct dirent* ent = NULL;
 	while ((ent = readdir(dir)) != NULL) {
 		if (ent->d_type != DT_CHR)
 			continue;
 		if (strncmp(ent->d_name, "vhci", 4))
 			continue;
+		char path[1024];
 		snprintf(path, sizeof(path), "/dev/%s", ent->d_name);
 		if (chmod(path, 0666))
 			fail("failed to chmod %s", path);
@@ -147,9 +145,7 @@ static int tunfd = -1;
 
 static void vsnprintf_check(char* str, size_t size, const char* format, va_list args)
 {
-	int rv;
-
-	rv = vsnprintf(str, size, format, args);
+	int rv = vsnprintf(str, size, format, args);
 	if (rv < 0)
 		fail("vsnprintf failed");
 	if ((size_t)rv >= size)
@@ -172,17 +168,15 @@ static void snprintf_check(char* str, size_t size, const char* format, ...)
 static void execute_command(bool panic, const char* format, ...)
 {
 	va_list args;
-	char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN];
-	int rv;
-
 	va_start(args, format);
 	// Executor process does not have any env, including PATH.
 	// On some distributions, system/shell adds a minimal PATH, on some it does not.
 	// Set own standard PATH to make it work across distributions.
+	char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN];
 	memcpy(command, PATH_PREFIX, PATH_PREFIX_LEN);
 	vsnprintf_check(command + PATH_PREFIX_LEN, COMMAND_MAX_LEN, format, args);
 	va_end(args);
-	rv = system(command);
+	int rv = system(command);
 	if (rv) {
 		if (panic)
 			fail("command '%s' failed: %d", &command[0], rv);
@@ -351,12 +345,11 @@ static long syz_extract_tcp_res(volatile long a0, volatile long a1, volatile lon
 	size_t length = rv;
 	debug_dump_data(data, length);
 
-	struct tcphdr* tcphdr;
-
 	if (length < sizeof(struct ether_header))
 		return (uintptr_t)-1;
 	struct ether_header* ethhdr = (struct ether_header*)&data[0];
 
+	struct tcphdr* tcphdr = 0;
 	if (ethhdr->ether_type == htons(ETHERTYPE_IP)) {
 		if (length < sizeof(struct ether_header) + sizeof(struct ip))
 			return (uintptr_t)-1;