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, 57 insertions, 90 deletions

diff --git a/executor/common_linux.h b/executor/common_linux.h
index b9a67418b..1d95a81b3 100644
--- a/executor/common_linux.h
+++ b/executor/common_linux.h
@@ -582,20 +582,18 @@ const int kInitNetNsFd = 239; // see kMaxFd
 static int netlink_devlink_id_get(struct nlmsg* nlmsg, int sock)
 {
 	struct genlmsghdr genlhdr;
-	struct nlattr* attr;
-	int err, n;
-	uint16 id = 0;
-
 	memset(&genlhdr, 0, sizeof(genlhdr));
 	genlhdr.cmd = CTRL_CMD_GETFAMILY;
 	netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
 	netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, DEVLINK_FAMILY_NAME, strlen(DEVLINK_FAMILY_NAME) + 1);
-	err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n);
+	int n = 0;
+	int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n);
 	if (err) {
 		debug("netlink: failed to get devlink family id: %s\n", strerror(err));
 		return -1;
 	}
-	attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr)));
+	uint16 id = 0;
+	struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr)));
 	for (; (char*)attr < nlmsg->buf + n; attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
 		if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
 			id = *(uint16*)(attr + 1);
@@ -796,20 +794,18 @@ enum wgallowedip_attribute {
 static int netlink_wireguard_id_get(struct nlmsg* nlmsg, int sock)
 {
 	struct genlmsghdr genlhdr;
-	struct nlattr* attr;
-	int err, n;
-	uint16 id = 0;
-
 	memset(&genlhdr, 0, sizeof(genlhdr));
 	genlhdr.cmd = CTRL_CMD_GETFAMILY;
 	netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
 	netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, WG_GENL_NAME, strlen(WG_GENL_NAME) + 1);
-	err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n);
+	int n = 0;
+	int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n);
 	if (err) {
 		debug("netlink: failed to get wireguard family id: %s\n", strerror(err));
 		return -1;
 	}
-	attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr)));
+	uint16 id = 0;
+	struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN + NLMSG_ALIGN(sizeof(genlhdr)));
 	for (; (char*)attr < nlmsg->buf + n; attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
 		if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
 			id = *(uint16*)(attr + 1);
@@ -1820,12 +1816,11 @@ 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 ethhdr))
 		return (uintptr_t)-1;
 	struct ethhdr* ethhdr = (struct ethhdr*)&data[0];
 
+	struct tcphdr* tcphdr = 0;
 	if (ethhdr->h_proto == htons(ETH_P_IP)) {
 		if (length < sizeof(struct ethhdr) + sizeof(struct iphdr))
 			return (uintptr_t)-1;
@@ -2395,7 +2390,6 @@ struct fs_image_segment {
 
 static unsigned long fs_image_segment_check(unsigned long size, unsigned long nsegs, long segments)
 {
-	unsigned long i;
 	// Strictly saying we ought to do a nonfailing copyout of segments into a local var.
 	// But some filesystems have large number of segments (2000+),
 	// we can't allocate that much on stack and allocating elsewhere is problematic,
@@ -2404,7 +2398,7 @@ static unsigned long fs_image_segment_check(unsigned long size, unsigned long ns
 
 	if (nsegs > IMAGE_MAX_SEGMENTS)
 		nsegs = IMAGE_MAX_SEGMENTS;
-	for (i = 0; i < nsegs; i++) {
+	for (unsigned long i = 0; i < nsegs; i++) {
 		if (segs[i].size > IMAGE_MAX_SIZE)
 			segs[i].size = IMAGE_MAX_SIZE;
 		segs[i].offset %= IMAGE_MAX_SIZE;
@@ -2423,9 +2417,7 @@ static unsigned long fs_image_segment_check(unsigned long size, unsigned long ns
 // syz_read_part_table(size intptr, nsegs len[segments], segments ptr[in, array[fs_image_segment]])
 static long syz_read_part_table(volatile unsigned long size, volatile unsigned long nsegs, volatile long segments)
 {
-	char loopname[64], linkname[64];
-	int loopfd, err = 0, res = -1;
-	unsigned long i, j;
+	int err = 0, res = -1, loopfd = -1;
 	size = fs_image_segment_check(size, nsegs, segments);
 	int memfd = syscall(sys_memfd_create, "syz_read_part_table", 0);
 	if (memfd == -1) {
@@ -2436,12 +2428,13 @@ static long syz_read_part_table(volatile unsigned long size, volatile unsigned l
 		err = errno;
 		goto error_close_memfd;
 	}
-	for (i = 0; i < nsegs; i++) {
+	for (unsigned long i = 0; i < nsegs; i++) {
 		struct fs_image_segment* segs = (struct fs_image_segment*)segments;
 		if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) {
 			debug("syz_read_part_table: pwrite[%u] failed: %d\n", (int)i, errno);
 		}
 	}
+	char loopname[64];
 	snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid);
 	loopfd = open(loopname, O_RDWR);
 	if (loopfd == -1) {
@@ -2475,10 +2468,11 @@ static long syz_read_part_table(volatile unsigned long size, volatile unsigned l
 	}
 	res = 0;
 	// If we managed to parse some partitions, symlink them into our work dir.
-	for (i = 1, j = 0; i < 8; i++) {
+	for (unsigned long i = 1, j = 0; i < 8; i++) {
 		snprintf(loopname, sizeof(loopname), "/dev/loop%llup%d", procid, (int)i);
 		struct stat statbuf;
 		if (stat(loopname, &statbuf) == 0) {
+			char linkname[64];
 			snprintf(linkname, sizeof(linkname), "./file%d", (int)j++);
 			if (symlink(loopname, linkname)) {
 				debug("syz_read_part_table: symlink(%s, %s) failed: %d\n", loopname, linkname, errno);
@@ -2509,10 +2503,7 @@ error:
 // }
 static long syz_mount_image(volatile long fsarg, volatile long dir, volatile unsigned long size, volatile unsigned long nsegs, volatile long segments, volatile long flags, volatile long optsarg)
 {
-	char loopname[64], fs[32], opts[256];
-	int loopfd, err = 0, res = -1;
-	unsigned long i;
-
+	int err = 0, res = -1, loopfd = -1;
 	size = fs_image_segment_check(size, nsegs, segments);
 	int memfd = syscall(sys_memfd_create, "syz_mount_image", 0);
 	if (memfd == -1) {
@@ -2523,12 +2514,13 @@ static long syz_mount_image(volatile long fsarg, volatile long dir, volatile uns
 		err = errno;
 		goto error_close_memfd;
 	}
-	for (i = 0; i < nsegs; i++) {
+	for (unsigned long i = 0; i < nsegs; i++) {
 		struct fs_image_segment* segs = (struct fs_image_segment*)segments;
 		if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) {
 			debug("syz_mount_image: pwrite[%u] failed: %d\n", (int)i, errno);
 		}
 	}
+	char loopname[64];
 	snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid);
 	loopfd = open(loopname, O_RDWR);
 	if (loopfd == -1) {
@@ -2548,8 +2540,10 @@ static long syz_mount_image(volatile long fsarg, volatile long dir, volatile uns
 		}
 	}
 	mkdir((char*)dir, 0777);
+	char fs[32];
 	memset(fs, 0, sizeof(fs));
 	strncpy(fs, (char*)fsarg, sizeof(fs) - 1);
+	char opts[256];
 	memset(opts, 0, sizeof(opts));
 	// Leave some space for the additional options we append below.
 	strncpy(opts, (char*)optsarg, sizeof(opts) - 32);
@@ -2730,11 +2724,7 @@ static struct arpt_table_desc arpt_tables[] = {
 
 static void checkpoint_iptables(struct ipt_table_desc* tables, int num_tables, int family, int level)
 {
-	struct ipt_get_entries entries;
-	socklen_t optlen;
-	int fd, i;
-
-	fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
+	int fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
 	if (fd == -1) {
 		switch (errno) {
 		case EAFNOSUPPORT:
@@ -2743,11 +2733,11 @@ static void checkpoint_iptables(struct ipt_table_desc* tables, int num_tables, i
 		}
 		fail("iptable checkpoint %d: socket failed", family);
 	}
-	for (i = 0; i < num_tables; i++) {
+	for (int i = 0; i < num_tables; i++) {
 		struct ipt_table_desc* table = &tables[i];
 		strcpy(table->info.name, table->name);
 		strcpy(table->replace.name, table->name);
-		optlen = sizeof(table->info);
+		socklen_t optlen = sizeof(table->info);
 		if (getsockopt(fd, level, IPT_SO_GET_INFO, &table->info, &optlen)) {
 			switch (errno) {
 			case EPERM:
@@ -2766,6 +2756,7 @@ static void checkpoint_iptables(struct ipt_table_desc* tables, int num_tables, i
 		if (table->info.num_entries > XT_MAX_ENTRIES)
 			fail("iptable checkpoint %s/%d: too many counters: %u",
 			     table->name, family, table->info.num_entries);
+		struct ipt_get_entries entries;
 		memset(&entries, 0, sizeof(entries));
 		strcpy(entries.name, table->name);
 		entries.size = table->info.size;
@@ -2785,13 +2776,7 @@ static void checkpoint_iptables(struct ipt_table_desc* tables, int num_tables, i
 
 static void reset_iptables(struct ipt_table_desc* tables, int num_tables, int family, int level)
 {
-	struct xt_counters counters[XT_MAX_ENTRIES];
-	struct ipt_get_entries entries;
-	struct ipt_getinfo info;
-	socklen_t optlen;
-	int fd, i;
-
-	fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
+	int fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
 	if (fd == -1) {
 		switch (errno) {
 		case EAFNOSUPPORT:
@@ -2800,16 +2785,18 @@ static void reset_iptables(struct ipt_table_desc* tables, int num_tables, int fa
 		}
 		fail("iptable %d: socket failed", family);
 	}
-	for (i = 0; i < num_tables; i++) {
+	for (int i = 0; i < num_tables; i++) {
 		struct ipt_table_desc* table = &tables[i];
 		if (table->info.valid_hooks == 0)
 			continue;
+		struct ipt_getinfo info;
 		memset(&info, 0, sizeof(info));
 		strcpy(info.name, table->name);
-		optlen = sizeof(info);
+		socklen_t optlen = sizeof(info);
 		if (getsockopt(fd, level, IPT_SO_GET_INFO, &info, &optlen))
 			fail("iptable %s/%d: getsockopt(IPT_SO_GET_INFO)", table->name, family);
 		if (memcmp(&table->info, &info, sizeof(table->info)) == 0) {
+			struct ipt_get_entries entries;
 			memset(&entries, 0, sizeof(entries));
 			strcpy(entries.name, table->name);
 			entries.size = table->info.size;
@@ -2820,6 +2807,7 @@ static void reset_iptables(struct ipt_table_desc* tables, int num_tables, int fa
 				continue;
 		}
 		debug("iptable %s/%d: resetting\n", table->name, family);
+		struct xt_counters counters[XT_MAX_ENTRIES];
 		table->replace.num_counters = info.num_entries;
 		table->replace.counters = counters;
 		optlen = sizeof(table->replace) - sizeof(table->replace.entrytable) + table->replace.size;
@@ -2831,12 +2819,7 @@ static void reset_iptables(struct ipt_table_desc* tables, int num_tables, int fa
 
 static void checkpoint_arptables(void)
 {
-	struct arpt_get_entries entries;
-	socklen_t optlen;
-	unsigned i;
-	int fd;
-
-	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 	if (fd == -1) {
 		switch (errno) {
 		case EAFNOSUPPORT:
@@ -2845,11 +2828,11 @@ static void checkpoint_arptables(void)
 		}
 		fail("arptable checkpoint: socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)");
 	}
-	for (i = 0; i < sizeof(arpt_tables) / sizeof(arpt_tables[0]); i++) {
+	for (unsigned i = 0; i < sizeof(arpt_tables) / sizeof(arpt_tables[0]); i++) {
 		struct arpt_table_desc* table = &arpt_tables[i];
 		strcpy(table->info.name, table->name);
 		strcpy(table->replace.name, table->name);
-		optlen = sizeof(table->info);
+		socklen_t optlen = sizeof(table->info);
 		if (getsockopt(fd, SOL_IP, ARPT_SO_GET_INFO, &table->info, &optlen)) {
 			switch (errno) {
 			case EPERM:
@@ -2867,6 +2850,7 @@ static void checkpoint_arptables(void)
 		if (table->info.num_entries > XT_MAX_ENTRIES)
 			fail("arptable checkpoint %s: too many counters: %u",
 			     table->name, table->info.num_entries);
+		struct arpt_get_entries entries;
 		memset(&entries, 0, sizeof(entries));
 		strcpy(entries.name, table->name);
 		entries.size = table->info.size;
@@ -2885,14 +2869,7 @@ static void checkpoint_arptables(void)
 
 static void reset_arptables()
 {
-	struct xt_counters counters[XT_MAX_ENTRIES];
-	struct arpt_get_entries entries;
-	struct arpt_getinfo info;
-	socklen_t optlen;
-	unsigned i;
-	int fd;
-
-	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 	if (fd == -1) {
 		switch (errno) {
 		case EAFNOSUPPORT:
@@ -2901,16 +2878,18 @@ static void reset_arptables()
 		}
 		fail("arptable: socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)");
 	}
-	for (i = 0; i < sizeof(arpt_tables) / sizeof(arpt_tables[0]); i++) {
+	for (unsigned i = 0; i < sizeof(arpt_tables) / sizeof(arpt_tables[0]); i++) {
 		struct arpt_table_desc* table = &arpt_tables[i];
 		if (table->info.valid_hooks == 0)
 			continue;
+		struct arpt_getinfo info;
 		memset(&info, 0, sizeof(info));
 		strcpy(info.name, table->name);
-		optlen = sizeof(info);
+		socklen_t optlen = sizeof(info);
 		if (getsockopt(fd, SOL_IP, ARPT_SO_GET_INFO, &info, &optlen))
 			fail("arptable %s:getsockopt(ARPT_SO_GET_INFO)", table->name);
 		if (memcmp(&table->info, &info, sizeof(table->info)) == 0) {
+			struct arpt_get_entries entries;
 			memset(&entries, 0, sizeof(entries));
 			strcpy(entries.name, table->name);
 			entries.size = table->info.size;
@@ -2924,6 +2903,7 @@ static void reset_arptables()
 			debug("arptable %s: header changed\n", table->name);
 		}
 		debug("arptable %s: resetting\n", table->name);
+		struct xt_counters counters[XT_MAX_ENTRIES];
 		table->replace.num_counters = info.num_entries;
 		table->replace.counters = counters;
 		optlen = sizeof(table->replace) - sizeof(table->replace.entrytable) + table->replace.size;
@@ -2981,11 +2961,7 @@ static struct ebt_table_desc ebt_tables[] = {
 
 static void checkpoint_ebtables(void)
 {
-	socklen_t optlen;
-	unsigned i;
-	int fd;
-
-	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 	if (fd == -1) {
 		switch (errno) {
 		case EAFNOSUPPORT:
@@ -2994,10 +2970,10 @@ static void checkpoint_ebtables(void)
 		}
 		fail("ebtable checkpoint: socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)");
 	}
-	for (i = 0; i < sizeof(ebt_tables) / sizeof(ebt_tables[0]); i++) {
+	for (size_t i = 0; i < sizeof(ebt_tables) / sizeof(ebt_tables[0]); i++) {
 		struct ebt_table_desc* table = &ebt_tables[i];
 		strcpy(table->replace.name, table->name);
-		optlen = sizeof(table->replace);
+		socklen_t optlen = sizeof(table->replace);
 		if (getsockopt(fd, SOL_IP, EBT_SO_GET_INIT_INFO, &table->replace, &optlen)) {
 			switch (errno) {
 			case EPERM:
@@ -3024,13 +3000,7 @@ static void checkpoint_ebtables(void)
 
 static void reset_ebtables()
 {
-	struct ebt_replace replace;
-	char entrytable[XT_TABLE_SIZE];
-	socklen_t optlen;
-	unsigned i, j, h;
-	int fd;
-
-	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 	if (fd == -1) {
 		switch (errno) {
 		case EAFNOSUPPORT:
@@ -3039,20 +3009,22 @@ static void reset_ebtables()
 		}
 		fail("ebtable: socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)");
 	}
-	for (i = 0; i < sizeof(ebt_tables) / sizeof(ebt_tables[0]); i++) {
+	for (unsigned i = 0; i < sizeof(ebt_tables) / sizeof(ebt_tables[0]); i++) {
 		struct ebt_table_desc* table = &ebt_tables[i];
 		if (table->replace.valid_hooks == 0)
 			continue;
+		struct ebt_replace replace;
 		memset(&replace, 0, sizeof(replace));
 		strcpy(replace.name, table->name);
-		optlen = sizeof(replace);
+		socklen_t optlen = sizeof(replace);
 		if (getsockopt(fd, SOL_IP, EBT_SO_GET_INFO, &replace, &optlen))
 			fail("ebtable %s: getsockopt(EBT_SO_GET_INFO)", table->name);
 		replace.num_counters = 0;
 		table->replace.entries = 0;
-		for (h = 0; h < NF_BR_NUMHOOKS; h++)
+		for (unsigned h = 0; h < NF_BR_NUMHOOKS; h++)
 			table->replace.hook_entry[h] = 0;
 		if (memcmp(&table->replace, &replace, sizeof(table->replace)) == 0) {
+			char entrytable[XT_TABLE_SIZE];
 			memset(&entrytable, 0, sizeof(entrytable));
 			replace.entries = entrytable;
 			optlen = sizeof(replace) + replace.entries_size;
@@ -3063,7 +3035,7 @@ static void reset_ebtables()
 		}
 		debug("ebtable %s: resetting\n", table->name);
 		// Kernel does not seem to return actual entry points (wat?).
-		for (j = 0, h = 0; h < NF_BR_NUMHOOKS; h++) {
+		for (unsigned j = 0, h = 0; h < NF_BR_NUMHOOKS; h++) {
 			if (table->replace.valid_hooks & (1 << h)) {
 				table->replace.hook_entry[h] = (struct ebt_entries*)table->entrytable + j;
 				j++;
@@ -3592,8 +3564,6 @@ static int namespace_sandbox_proc(void* arg)
 #define SYZ_HAVE_SANDBOX_NAMESPACE 1
 static int do_sandbox_namespace(void)
 {
-	int pid;
-
 	setup_common();
 #if SYZ_EXECUTOR || SYZ_VHCI_INJECTION
 	// HCIDEVUP requires CAP_ADMIN, so this needs to happen early.
@@ -3602,8 +3572,8 @@ static int do_sandbox_namespace(void)
 	real_uid = getuid();
 	real_gid = getgid();
 	mprotect(sandbox_stack, 4096, PROT_NONE); // to catch stack underflows
-	pid = clone(namespace_sandbox_proc, &sandbox_stack[sizeof(sandbox_stack) - 64],
-		    CLONE_NEWUSER | CLONE_NEWPID, 0);
+	int pid = clone(namespace_sandbox_proc, &sandbox_stack[sizeof(sandbox_stack) - 64],
+			CLONE_NEWUSER | CLONE_NEWPID, 0);
 	return wait_for_loop(pid);
 }
 #endif
@@ -3800,9 +3770,8 @@ static int do_sandbox_android(void)
 // Moreover, a mount can be re-mounted as read-only and then we will fail to make a dir empty.
 static void remove_dir(const char* dir)
 {
-	DIR* dp;
-	struct dirent* ep;
 	int iter = 0;
+	DIR* dp = 0;
 retry:
 #if not SYZ_SANDBOX_ANDROID
 	if (!flag_sandbox_android) {
@@ -3821,6 +3790,7 @@ retry:
 		}
 		exitf("opendir(%s) failed", dir);
 	}
+	struct dirent* ep = 0;
 	while ((ep = readdir(dp))) {
 		if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
 			continue;
@@ -3874,8 +3844,7 @@ retry:
 		}
 	}
 	closedir(dp);
-	int i;
-	for (i = 0;; i++) {
+	for (int i = 0;; i++) {
 		if (rmdir(dir) == 0)
 			break;
 		if (i < 100) {
@@ -3970,9 +3939,8 @@ static void kill_and_wait(int pid, int* status)
 {
 	kill(-pid, SIGKILL);
 	kill(pid, SIGKILL);
-	int i;
 	// First, give it up to 100 ms to surrender.
-	for (i = 0; i < 100; i++) {
+	for (int i = 0; i < 100; i++) {
 		if (waitpid(-1, status, WNOHANG | __WALL) == pid)
 			return;
 		usleep(1000);
@@ -4085,8 +4053,7 @@ static void close_fds()
 	// so close all opened file descriptors.
 	// Also close all USB emulation descriptors to trigger exit from USB
 	// event loop to collect coverage.
-	int fd;
-	for (fd = 3; fd < MAX_FDS; fd++)
+	for (int fd = 3; fd < MAX_FDS; fd++)
 		close(fd);
 }
 #endif