[PATCH bpf-next v1 2/7] tools: bpftool: fix error message on invalid argument count

[Alban Crequy]

From: Alban Crequy <alban@xxxxxxxxxx>

Symptoms:
$ sudo bpftool map create /sys/fs/bpf/dir/foobar type hash key 8 value 8 entries
Error: '8' needs at least 2 arguments, 1 found

After this patch:
$ sudo bpftool map create /sys/fs/bpf/dir/foobar type hash key 8 value 8 entries
Error: can't parse max entries: missing argument

Signed-off-by: Alban Crequy <alban@xxxxxxxxxx>
---
 tools/bpf/bpftool/common.c |  5 +++++
 tools/bpf/bpftool/main.h   | 11 +++++++----
 tools/bpf/bpftool/map.c    | 15 ++++++++++++---
 tools/bpf/bpftool/prog.c   |  2 --
 4 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index f7261fad45c1..e560cd8f66bc 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -627,6 +627,11 @@ int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what)
 		return -1;
 	}
 
+	if (*argc == 0) {
+		p_err("can't parse %s: missing argument", what);
+		return -1;
+	}
+
 	*val = strtoul(**argv, &endptr, 0);
 	if (*endptr) {
 		p_err("can't parse %s as %s", **argv, what);
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index d7dd84d3c660..7fc2973446d0 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -22,14 +22,17 @@
 #define NEXT_ARGP()	({ (*argc)--; (*argv)++; if (*argc < 0) usage(); })
 #define BAD_ARG()	({ p_err("what is '%s'?", *argv); -1; })
 #define GET_ARG()	({ argc--; *argv++; })
-#define REQ_ARGS(cnt)							\
+
+#define REQ_ARGS(cnt)	REQ_ARGS_GENERIC(cnt, argc, argv)
+#define REQ_ARGSP(cnt)	REQ_ARGS_GENERIC(cnt, *argc, *argv)
+#define REQ_ARGS_GENERIC(cnt, ARGC, ARGV)				\
 	({								\
 		int _cnt = (cnt);					\
 		bool _res;						\
 									\
-		if (argc < _cnt) {					\
-			p_err("'%s' needs at least %d arguments, %d found", \
-			      argv[-1], _cnt, argc);			\
+		if ((ARGC) < _cnt) {					\
+			p_err("'%s' needs at least %d arguments, %d found",	\
+			      (ARGV)[-1], _cnt, (ARGC));			\
 			_res = false;					\
 		} else {						\
 			_res = true;					\
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 994a7e0d16fb..18f9bc3aed4f 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -98,6 +98,9 @@ int map_parse_fd(int *argc, char ***argv)
 		char *endptr;
 
 		NEXT_ARGP();
+		if (!REQ_ARGSP(1)) {
+			return -1;
+		}
 
 		id = strtoul(**argv, &endptr, 0);
 		if (*endptr) {
@@ -114,6 +117,9 @@ int map_parse_fd(int *argc, char ***argv)
 		char *path;
 
 		NEXT_ARGP();
+		if (!REQ_ARGSP(1)) {
+			return -1;
+		}
 
 		path = **argv;
 		NEXT_ARGP();
@@ -1100,11 +1106,10 @@ static int do_create(int argc, char **argv)
 	pinfile = GET_ARG();
 
 	while (argc) {
-		if (!REQ_ARGS(2))
-			return -1;
-
 		if (is_prefix(*argv, "type")) {
 			NEXT_ARG();
+			if (!REQ_ARGS(1))
+				return -1;
 
 			if (attr.map_type) {
 				p_err("map type already specified");
@@ -1119,6 +1124,8 @@ static int do_create(int argc, char **argv)
 			NEXT_ARG();
 		} else if (is_prefix(*argv, "name")) {
 			NEXT_ARG();
+			if (!REQ_ARGS(1))
+				return -1;
 			attr.name = GET_ARG();
 		} else if (is_prefix(*argv, "key")) {
 			if (parse_u32_arg(&argc, &argv, &attr.key_size,
@@ -1138,6 +1145,8 @@ static int do_create(int argc, char **argv)
 				return -1;
 		} else if (is_prefix(*argv, "dev")) {
 			NEXT_ARG();
+			if (!REQ_ARGS(1))
+				return -1;
 
 			if (attr.map_ifindex) {
 				p_err("offload device already specified");
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 8ef80d65a474..e0875ef5e444 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -836,8 +836,6 @@ static int parse_attach_detach_args(int argc, char **argv, int *progfd,
 	}
 
 	NEXT_ARG();
-	if (!REQ_ARGS(2))
-		return -EINVAL;
 
 	*mapfd = map_parse_fd(&argc, &argv);
 	if (*mapfd < 0)
-- 
2.20.1