executor: check format strings

I see a crash which says:

	#0: too much cover 0 (errno 0)

while the code is:

	uint64_t n = ...;
	if (n >= kCoverSize)
		fail("#%d: too much cover %u", th->id, n);

It seems that the high part of n is set, but we don't see it.

Add printf format attribute to fail and friends and fix all similar cases.
Caught a bunch of similar cases and a missing argument in:

exitf("opendir(%s) failed due to NOFILE, exiting");

5 files changed, 40 insertions, 35 deletions

diff --git a/pkg/csource/akaros_common.go b/pkg/csource/akaros_common.go
index 8bc422b6f..949a6ce8e 100644
--- a/pkg/csource/akaros_common.go
+++ b/pkg/csource/akaros_common.go
@@ -67,17 +67,19 @@ __attribute__((noreturn)) static void doexit(int status)
 #if defined(SYZ_EXECUTOR)
 #define exit vsnprintf
 #define _exit vsnprintf
-#endif
 
-#if defined(SYZ_EXECUTOR)
+#define uint64_t unsigned long long
+
 #if defined(__GNUC__)
 #define SYSCALLAPI
 #define NORETURN __attribute__((noreturn))
 #define ALIGNED(N) __attribute__((aligned(N)))
+#define PRINTF __attribute__((format(printf, 1, 2)))
 #else
 #define SYSCALLAPI WINAPI
 #define NORETURN __declspec(noreturn)
 #define ALIGNED(N) __declspec(align(N))
+#define PRINTF
 #endif
 
 typedef long(SYSCALLAPI* syscall_t)(long, long, long, long, long, long, long, long, long);
@@ -107,7 +109,7 @@ const int kErrorStatus = 68;
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT)) ||            \
     defined(SYZ_USE_TMP_DIR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_SANDBOX_NAMESPACE) || \
     defined(SYZ_SANDBOX_NONE) || defined(SYZ_SANDBOX_SETUID) || defined(__NR_syz_kvm_setup_cpu)
-NORETURN static void fail(const char* msg, ...)
+NORETURN PRINTF static void fail(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -120,7 +122,7 @@ NORETURN static void fail(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR)
-NORETURN static void error(const char* msg, ...)
+NORETURN PRINTF static void error(const char* msg, ...)
 {
 	va_list args;
 	va_start(args, msg);
@@ -132,7 +134,7 @@ NORETURN static void error(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT) && defined(SYZ_USE_TMP_DIR)) || defined(SYZ_FAULT_INJECTION)
-NORETURN static void exitf(const char* msg, ...)
+NORETURN PRINTF static void exitf(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -147,7 +149,7 @@ NORETURN static void exitf(const char* msg, ...)
 #if defined(SYZ_EXECUTOR) || defined(SYZ_DEBUG)
 static int flag_debug;
 
-static void debug(const char* msg, ...)
+PRINTF static void debug(const char* msg, ...)
 {
 	if (!flag_debug)
 		return;
diff --git a/pkg/csource/csource.go b/pkg/csource/csource.go
index 14f381451..13377c57e 100644
--- a/pkg/csource/csource.go
+++ b/pkg/csource/csource.go
@@ -143,6 +143,7 @@ func Write(p *prog.Prog, opts Options) ([]byte, error) {
 		out0 = re.ReplaceAllString(out0, "")
 	}
 	out0 = strings.Replace(out0, "NORETURN", "", -1)
+	out0 = strings.Replace(out0, "PRINTF", "", -1)
 
 	// Remove duplicate new lines.
 	out1 := []byte(out0)
diff --git a/pkg/csource/freebsd_common.go b/pkg/csource/freebsd_common.go
index 9ab6203f7..0d85c6d66 100644
--- a/pkg/csource/freebsd_common.go
+++ b/pkg/csource/freebsd_common.go
@@ -58,17 +58,19 @@ __attribute__((noreturn)) static void doexit(int status)
 #if defined(SYZ_EXECUTOR)
 #define exit vsnprintf
 #define _exit vsnprintf
-#endif
 
-#if defined(SYZ_EXECUTOR)
+#define uint64_t unsigned long long
+
 #if defined(__GNUC__)
 #define SYSCALLAPI
 #define NORETURN __attribute__((noreturn))
 #define ALIGNED(N) __attribute__((aligned(N)))
+#define PRINTF __attribute__((format(printf, 1, 2)))
 #else
 #define SYSCALLAPI WINAPI
 #define NORETURN __declspec(noreturn)
 #define ALIGNED(N) __declspec(align(N))
+#define PRINTF
 #endif
 
 typedef long(SYSCALLAPI* syscall_t)(long, long, long, long, long, long, long, long, long);
@@ -98,7 +100,7 @@ const int kErrorStatus = 68;
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT)) ||            \
     defined(SYZ_USE_TMP_DIR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_SANDBOX_NAMESPACE) || \
     defined(SYZ_SANDBOX_NONE) || defined(SYZ_SANDBOX_SETUID) || defined(__NR_syz_kvm_setup_cpu)
-NORETURN static void fail(const char* msg, ...)
+NORETURN PRINTF static void fail(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -111,7 +113,7 @@ NORETURN static void fail(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR)
-NORETURN static void error(const char* msg, ...)
+NORETURN PRINTF static void error(const char* msg, ...)
 {
 	va_list args;
 	va_start(args, msg);
@@ -123,7 +125,7 @@ NORETURN static void error(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT) && defined(SYZ_USE_TMP_DIR)) || defined(SYZ_FAULT_INJECTION)
-NORETURN static void exitf(const char* msg, ...)
+NORETURN PRINTF static void exitf(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -138,7 +140,7 @@ NORETURN static void exitf(const char* msg, ...)
 #if defined(SYZ_EXECUTOR) || defined(SYZ_DEBUG)
 static int flag_debug;
 
-static void debug(const char* msg, ...)
+PRINTF static void debug(const char* msg, ...)
 {
 	if (!flag_debug)
 		return;
@@ -208,13 +210,11 @@ static void segv_handler(int sig, siginfo_t* info, void* uctx)
 	const uintptr_t prog_start = 1 << 20;
 	const uintptr_t prog_end = 100 << 20;
 	if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) {
-		debug("SIGSEGV on %p, skipping\n", addr);
+		debug("SIGSEGV on %p, skipping\n", (void*)addr);
 		_longjmp(segv_env, 1);
 	}
-	debug("SIGSEGV on %p, exiting\n", addr);
+	debug("SIGSEGV on %p, exiting\n", (void*)addr);
 	doexit(sig);
-	for (;;) {
-	}
 }
 
 static void install_segv_handler()
diff --git a/pkg/csource/linux_common.go b/pkg/csource/linux_common.go
index 1ec165b89..329c7e5e2 100644
--- a/pkg/csource/linux_common.go
+++ b/pkg/csource/linux_common.go
@@ -146,17 +146,19 @@ __attribute__((noreturn)) static void doexit(int status)
 #if defined(SYZ_EXECUTOR)
 #define exit vsnprintf
 #define _exit vsnprintf
-#endif
 
-#if defined(SYZ_EXECUTOR)
+#define uint64_t unsigned long long
+
 #if defined(__GNUC__)
 #define SYSCALLAPI
 #define NORETURN __attribute__((noreturn))
 #define ALIGNED(N) __attribute__((aligned(N)))
+#define PRINTF __attribute__((format(printf, 1, 2)))
 #else
 #define SYSCALLAPI WINAPI
 #define NORETURN __declspec(noreturn)
 #define ALIGNED(N) __declspec(align(N))
+#define PRINTF
 #endif
 
 typedef long(SYSCALLAPI* syscall_t)(long, long, long, long, long, long, long, long, long);
@@ -186,7 +188,7 @@ const int kErrorStatus = 68;
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT)) ||            \
     defined(SYZ_USE_TMP_DIR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_SANDBOX_NAMESPACE) || \
     defined(SYZ_SANDBOX_NONE) || defined(SYZ_SANDBOX_SETUID) || defined(__NR_syz_kvm_setup_cpu)
-NORETURN static void fail(const char* msg, ...)
+NORETURN PRINTF static void fail(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -199,7 +201,7 @@ NORETURN static void fail(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR)
-NORETURN static void error(const char* msg, ...)
+NORETURN PRINTF static void error(const char* msg, ...)
 {
 	va_list args;
 	va_start(args, msg);
@@ -211,7 +213,7 @@ NORETURN static void error(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT) && defined(SYZ_USE_TMP_DIR)) || defined(SYZ_FAULT_INJECTION)
-NORETURN static void exitf(const char* msg, ...)
+NORETURN PRINTF static void exitf(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -226,7 +228,7 @@ NORETURN static void exitf(const char* msg, ...)
 #if defined(SYZ_EXECUTOR) || defined(SYZ_DEBUG)
 static int flag_debug;
 
-static void debug(const char* msg, ...)
+PRINTF static void debug(const char* msg, ...)
 {
 	if (!flag_debug)
 		return;
@@ -296,10 +298,10 @@ static void segv_handler(int sig, siginfo_t* info, void* uctx)
 	const uintptr_t prog_start = 1 << 20;
 	const uintptr_t prog_end = 100 << 20;
 	if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) {
-		debug("SIGSEGV on %p, skipping\n", addr);
+		debug("SIGSEGV on %p, skipping\n", (void*)addr);
 		_longjmp(segv_env, 1);
 	}
-	debug("SIGSEGV on %p, exiting\n", addr);
+	debug("SIGSEGV on %p, exiting\n", (void*)addr);
 	doexit(sig);
 }
 
@@ -1931,7 +1933,7 @@ retry:
 	dp = opendir(dir);
 	if (dp == NULL) {
 		if (errno == EMFILE) {
-			exitf("opendir(%s) failed due to NOFILE, exiting");
+			exitf("opendir(%s) failed due to NOFILE, exiting", dir);
 		}
 		exitf("opendir(%s) failed", dir);
 	}
diff --git a/pkg/csource/netbsd_common.go b/pkg/csource/netbsd_common.go
index 80e52e8ed..86c95859b 100644
--- a/pkg/csource/netbsd_common.go
+++ b/pkg/csource/netbsd_common.go
@@ -58,17 +58,19 @@ __attribute__((noreturn)) static void doexit(int status)
 #if defined(SYZ_EXECUTOR)
 #define exit vsnprintf
 #define _exit vsnprintf
-#endif
 
-#if defined(SYZ_EXECUTOR)
+#define uint64_t unsigned long long
+
 #if defined(__GNUC__)
 #define SYSCALLAPI
 #define NORETURN __attribute__((noreturn))
 #define ALIGNED(N) __attribute__((aligned(N)))
+#define PRINTF __attribute__((format(printf, 1, 2)))
 #else
 #define SYSCALLAPI WINAPI
 #define NORETURN __declspec(noreturn)
 #define ALIGNED(N) __declspec(align(N))
+#define PRINTF
 #endif
 
 typedef long(SYSCALLAPI* syscall_t)(long, long, long, long, long, long, long, long, long);
@@ -98,7 +100,7 @@ const int kErrorStatus = 68;
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT)) ||            \
     defined(SYZ_USE_TMP_DIR) || defined(SYZ_TUN_ENABLE) || defined(SYZ_SANDBOX_NAMESPACE) || \
     defined(SYZ_SANDBOX_NONE) || defined(SYZ_SANDBOX_SETUID) || defined(__NR_syz_kvm_setup_cpu)
-NORETURN static void fail(const char* msg, ...)
+NORETURN PRINTF static void fail(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -111,7 +113,7 @@ NORETURN static void fail(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR)
-NORETURN static void error(const char* msg, ...)
+NORETURN PRINTF static void error(const char* msg, ...)
 {
 	va_list args;
 	va_start(args, msg);
@@ -123,7 +125,7 @@ NORETURN static void error(const char* msg, ...)
 #endif
 
 #if defined(SYZ_EXECUTOR) || (defined(SYZ_REPEAT) && defined(SYZ_WAIT_REPEAT) && defined(SYZ_USE_TMP_DIR)) || defined(SYZ_FAULT_INJECTION)
-NORETURN static void exitf(const char* msg, ...)
+NORETURN PRINTF static void exitf(const char* msg, ...)
 {
 	int e = errno;
 	va_list args;
@@ -138,7 +140,7 @@ NORETURN static void exitf(const char* msg, ...)
 #if defined(SYZ_EXECUTOR) || defined(SYZ_DEBUG)
 static int flag_debug;
 
-static void debug(const char* msg, ...)
+PRINTF static void debug(const char* msg, ...)
 {
 	if (!flag_debug)
 		return;
@@ -208,13 +210,11 @@ static void segv_handler(int sig, siginfo_t* info, void* uctx)
 	const uintptr_t prog_start = 1 << 20;
 	const uintptr_t prog_end = 100 << 20;
 	if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) {
-		debug("SIGSEGV on %p, skipping\n", addr);
+		debug("SIGSEGV on %p, skipping\n", (void*)addr);
 		_longjmp(segv_env, 1);
 	}
-	debug("SIGSEGV on %p, exiting\n", addr);
+	debug("SIGSEGV on %p, exiting\n", (void*)addr);
 	doexit(sig);
-	for (;;) {
-	}
 }
 
 static void install_segv_handler()