syscall format - fcntl fixes

src/intercept_log.c

@@ -214,7 +214,11 @@ static char *
 print_flag_set(char *buffer_start, char *c, long flags,
 		const struct flag_desc *desc)
 {
-	while (flags != 0 && desc->flag != 0) {
+	bool is_zero = flags == 0;
+	while (flags != 0 && desc->printable_name != NULL) {
+		if (is_zero && desc->flag == 0)
+			return print_flag(buffer_start, c,
+						desc->printable_name);
 		if ((flags & desc->flag) != 0) {
 			c = print_flag(buffer_start, c, desc->printable_name);
 			flags &= ~desc->flag;
@@ -543,7 +547,7 @@ static const struct flag_desc flock_type[] = {
 	FLAG_ENTRY(F_RDLCK),
 	FLAG_ENTRY(F_WRLCK),
 	FLAG_ENTRY(F_UNLCK),
-	{ .flag = 0, }
+	{ 0, }
 };
 
 static char *
@@ -599,13 +603,15 @@ static const struct flag_desc fcntl_cmds[] = {
 	FLAG_ENTRY(F_SEAL_GROW),
 	FLAG_ENTRY(F_SEAL_WRITE),
 #endif
-	{ .flag = 0, }
+	{ 0, }
 };
 
 static char *
 print_fcntl_cmd(char *buffer, int cmd)
 {
-	for (const struct flag_desc *d = fcntl_cmds; d->flag != 0; ++d) {
+	for (const struct flag_desc *d = fcntl_cmds;
+		d->printable_name != NULL;
+		++d) {
 		if (d->flag == cmd)
 			return print_cstr(buffer, d->printable_name);
 	}
@@ -633,11 +639,11 @@ print_fcntl_flock(char *buffer, long arg)
 	buffer = print_signed_dec(buffer, fl->l_type);
 	buffer = print_cstr(buffer, " (");
 	buffer = print_flag_set(buffer, buffer, fl->l_type, flock_type);
-	buffer = print_cstr(buffer, " ), .l_whence = ");
+	buffer = print_cstr(buffer, "), .l_whence = ");
 	buffer = print_signed_dec(buffer, fl->l_whence);
 	buffer = print_cstr(buffer, " (");
 	buffer = print_seek_whence(buffer, fl->l_whence);
-	buffer = print_cstr(buffer, " ), .l_start = ");
+	buffer = print_cstr(buffer, "), .l_start = ");
 	buffer = print_signed_dec(buffer, fl->l_start);
 	buffer = print_cstr(buffer, ", .l_len = ");
 	buffer = print_signed_dec(buffer, fl->l_len);
@@ -650,7 +656,7 @@ print_fcntl_flock(char *buffer, long arg)
 
 
 static char *
-arg_print_fcntl_args(char *buffer, const struct syscall_desc *desc, int i,
+arg_print_fcntl_cmd(char *buffer, const struct syscall_desc *desc, int i,
 				enum intercept_log_result result_status,
 				long result)
 {
@@ -662,23 +668,23 @@ arg_print_fcntl_args(char *buffer, const struct syscall_desc *desc, int i,
 	buffer = print_signed_dec(buffer, cmd);
 	buffer = print_cstr(buffer, " (");
 	buffer = print_fcntl_cmd(buffer, cmd);
-	buffer = print_cstr(buffer, "), ");
-	buffer = print_pointer(buffer, desc->args[i + 1]);
-
-	switch (cmd) {
-		case F_GETLK:
-		case F_SETLK:
-		case F_SETLKW:
-		case F_OFD_GETLK:
-		case F_OFD_SETLK:
-		case F_OFD_SETLKW:
-			buffer = print_fcntl_flock(buffer, desc->args[i + 1]);
-			break;
-	}
+	buffer = print_cstr(buffer, ")");
 
 	return buffer;
 }
 
+static char *
+arg_print_flock(char *buffer, const struct syscall_desc *desc, int i,
+				enum intercept_log_result result_status,
+				long result)
+{
+	(void) result_status;
+	(void) result;
+
+	buffer = print_pointer(buffer, desc->args[i]);
+	return print_fcntl_flock(buffer, desc->args[i]);
+}
+
 static char *
 arg_print_clone_flags(char *buffer, const struct syscall_desc *desc, int i,
 				enum intercept_log_result result_status,
@@ -757,12 +763,13 @@ static const arg_printer_func arg_printer_func_table[] = {
 	[arg_cstr] = arg_print_cstr,
 	[arg_buf_in] = arg_print_input_buf,
 	[arg_buf_out] = arg_print_output_buf,
-	[arg_fcntl_args] = arg_print_fcntl_args,
+	[arg_fcntl_cmd] = arg_print_fcntl_cmd,
 	[arg_clone_flags] = arg_print_clone_flags,
 	[arg_seek_whence] = arg_print_seek_whence,
 	[arg_2fds] = arg_print_2fds,
 	[arg_pipe2_flags] = arg_print_pipe2_flags,
-	[arg_access_mode] = arg_print_access_mode
+	[arg_access_mode] = arg_print_access_mode,
+	[arg_flock] = arg_print_flock
 };
 
 static const return_value_printer_func return_value_printer_table[] = {

src/syscall_formats.c

@@ -113,7 +113,7 @@ static const struct syscall_format formats[] = {
 	SARGS(msgsnd, rdec, arg_, arg_, arg_, arg_),
 	SARGS(msgrcv, rdec, arg_, arg_, arg_, arg_, arg_),
 	SARGS(msgctl, rdec, arg_, arg_, arg_),
-	SARGS(fcntl, rdec, arg_fd, arg_fcntl_args, arg_),
+	SARGS(fcntl, rdec, arg_fd, arg_fcntl_cmd, arg_),
 	SARGS(flock, rdec, arg_fd, arg_),
 	SARGS(fsync, rdec, arg_fd),
 	SARGS(fdatasync, rdec, arg_fd),
@@ -402,9 +402,31 @@ static struct syscall_format open_with_o_creat = {.name = "open", rdec,
 static struct syscall_format openat_with_o_creat = {.name = "openat", rdec,
 	{arg_atfd, arg_cstr, arg_open_flags, arg_oct_mode}};
 
+static struct syscall_format fcntl_with_flock = {.name = "fcntl", rdec,
+	{arg_fd, arg_fcntl_cmd, arg_flock}};
+
 static struct syscall_format unkown = {.name = NULL, rdec,
 	{arg_, arg_, arg_, arg_, arg_, arg_}};
 
+static bool
+is_fcntl_with_flock(const struct syscall_desc *desc)
+{
+	if (desc->nr != SYS_fcntl)
+		return false;
+
+	switch ((int)desc->args[1]) {
+		case F_GETLK:
+		case F_SETLK:
+		case F_SETLKW:
+		case F_OFD_GETLK:
+		case F_OFD_SETLK:
+		case F_OFD_SETLKW:
+			return true;
+		default:
+			return false;
+	}
+}
+
 const struct syscall_format *
 get_syscall_format(const struct syscall_desc *desc)
 {
@@ -420,5 +442,8 @@ get_syscall_format(const struct syscall_desc *desc)
 	if (desc->nr == SYS_openat && ((desc->args[2] & O_CREAT) == O_CREAT))
 		return &openat_with_o_creat;
 
+	if (is_fcntl_with_flock(desc))
+		return &fcntl_with_flock;
+
 	return formats + desc->nr;
 }

src/syscall_formats.h

@@ -59,12 +59,13 @@ enum arg_format {
 	arg_fd, /* fd argument - not the first argument of *at syscalls */
 	arg_atfd, /* fd argument - the first argument of *at syscalls */
 	arg_pointer, /* general pointer argument */
-	arg_fcntl_args, /* 2nd (and 3rd) argument of fcntl */
+	arg_fcntl_cmd, /* 2nd argument of fcntl */
 	arg_clone_flags, /* 1st argument of clone */
 	arg_seek_whence, /* 3rd argument of lseek */
 	arg_2fds, /* array of 2 int fd numbers */
 	arg_pipe2_flags, /* second argument of pipe2 */
-	arg_access_mode /* second argument of access */
+	arg_access_mode, /* second argument of access */
+	arg_flock /* pointer to struct flock */
 };
 
 /*

test/libcintercept3.log.match

@@ -300,10 +300,12 @@ $(S) $(XX) -- msgrcv(0x1, 0x123000, 0x1, 0x1, 0x1) = ?
 $(S) $(XX) -- msgrcv(0x1, 0x123000, 0x1, 0x1, 0x1) = 22
 $(S) $(XX) -- msgctl(0x1, 0x2, 0x123000) = ?
 $(S) $(XX) -- msgctl(0x1, 0x2, 0x123000) = 22
-$(S) $(XX) -- fcntl(1, 1030 (unknown), 0x0000000000000003, 0x3) = ?
-$(S) $(XX) -- fcntl(1, 1030 (unknown), 0x0000000000000003, 0x3) = 22
-$(S) $(XX) -- fcntl(10, 4 (unknown), 0x0000000000040000, 0x40000) = ?
-$(S) $(XX) -- fcntl(10, 4 (unknown), 0x0000000000040000, 0x40000) = 22
+$(S) $(XX) -- fcntl(1, 1030 (F_DUPFD_CLOEXEC), 0x3) = ?
+$(S) $(XX) -- fcntl(1, 1030 (F_DUPFD_CLOEXEC), 0x3) = 22
+$(S) $(XX) -- fcntl(10, 4 (F_SETFL), 0x40000) = ?
+$(S) $(XX) -- fcntl(10, 4 (F_SETFL), 0x40000) = 22
+$(S) $(XX) -- fcntl(11, 6 (F_SETLK), $(XX) ({.l_type = 1 (F_WRLCK), .l_whence = 2 (SEEK_END), .l_start = 123, .l_len = 456, .l_pid = 768})) = ?
+$(S) $(XX) -- fcntl(11, 6 (F_SETLK), $(XX) ({.l_type = 1 (F_WRLCK), .l_whence = 2 (SEEK_END), .l_start = 123, .l_len = 456, .l_pid = 768})) = 22
 $(S) $(XX) -- flock(1, 0x2) = ?
 $(S) $(XX) -- flock(1, 0x2) = 22
 $(S) $(XX) -- fsync(2) = ?

test/syscall_format.c

@@ -245,6 +245,14 @@ main(int argc, char **argv)
 
 	struct utsname uname_buf;
 
+	struct flock fl = {
+		.l_type = F_WRLCK,
+		.l_whence = SEEK_END,
+		.l_start = 123,
+		.l_len = 456,
+		.l_pid = 768
+	};
+
 	magic_syscall_start_log(argv[1], "1");
 
 
@@ -445,6 +453,7 @@ main(int argc, char **argv)
 
 	fcntl(1, F_DUPFD_CLOEXEC, 3, 4);
 	fcntl(10, F_SETFL, O_NOATIME);
+	fcntl(11, F_SETLK, &fl);
 	flock(1, LOCK_EX);
 	fsync(2);
 	fdatasync(2);