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[bpf-next,v2,1/2] libbpf: Add pathname_concat() helper

Message ID 1663313820-29918-1-git-send-email-wangyufen@huawei.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [bpf-next,v2,1/2] libbpf: Add pathname_concat() helper | expand

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Commit Message

wangyufen Sept. 16, 2022, 7:36 a.m. UTC 
Move snprintf and len check to common helper pathname_concat() to make the
code simpler.

Signed-off-by: Wang Yufen <wangyufen@huawei.com>
---
 tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++-------------------------------
 1 file changed, 29 insertions(+), 47 deletions(-)

Comments

Daniel Borkmann Sept. 16, 2022, 3:53 p.m. UTC | #1 
On 9/16/22 9:36 AM, Wang Yufen wrote:
> Move snprintf and len check to common helper pathname_concat() to make the
> code simpler.
> 
> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
> ---
>   tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++-------------------------------
>   1 file changed, 29 insertions(+), 47 deletions(-)
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 3ad1392..7ab977c 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -2096,19 +2096,30 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf,
>   	return true;
>   }
>   
> +static int pathname_concat(const char *path, const char *name, char *buf)
> +{
> +	int len;
> +
> +	len = snprintf(buf, PATH_MAX, "%s/%s", path, name);
> +	if (len < 0)
> +		return -EINVAL;
> +	if (len >= PATH_MAX)
> +		return -ENAMETOOLONG;
> +
> +	return 0;
> +}
> +
>   static int build_map_pin_path(struct bpf_map *map, const char *path)
>   {
>   	char buf[PATH_MAX];
> -	int len;
> +	int err;
>   
>   	if (!path)
>   		path = "/sys/fs/bpf";
>   
> -	len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
> -	if (len < 0)
> -		return -EINVAL;
> -	else if (len >= PATH_MAX)
> -		return -ENAMETOOLONG;
> +	err = pathname_concat(path, bpf_map__name(map), buf);

Small nit, but would be good to not make the assumption that buf is always
PATH_MAX so lets add size_t len to pathname_concat().

> +	if (err)
> +		return err;
>   
>   	return bpf_map__set_pin_path(map, buf);
>   }
diff mbox series

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3ad1392..7ab977c 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2096,19 +2096,30 @@  static bool get_map_field_int(const char *map_name, const struct btf *btf,
 	return true;
 }
 
+static int pathname_concat(const char *path, const char *name, char *buf)
+{
+	int len;
+
+	len = snprintf(buf, PATH_MAX, "%s/%s", path, name);
+	if (len < 0)
+		return -EINVAL;
+	if (len >= PATH_MAX)
+		return -ENAMETOOLONG;
+
+	return 0;
+}
+
 static int build_map_pin_path(struct bpf_map *map, const char *path)
 {
 	char buf[PATH_MAX];
-	int len;
+	int err;
 
 	if (!path)
 		path = "/sys/fs/bpf";
 
-	len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
-	if (len < 0)
-		return -EINVAL;
-	else if (len >= PATH_MAX)
-		return -ENAMETOOLONG;
+	err = pathname_concat(path, bpf_map__name(map), buf);
+	if (err)
+		return err;
 
 	return bpf_map__set_pin_path(map, buf);
 }
@@ -7961,17 +7972,9 @@  int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
 			continue;
 
 		if (path) {
-			int len;
-
-			len = snprintf(buf, PATH_MAX, "%s/%s", path,
-				       bpf_map__name(map));
-			if (len < 0) {
-				err = -EINVAL;
-				goto err_unpin_maps;
-			} else if (len >= PATH_MAX) {
-				err = -ENAMETOOLONG;
+			err = pathname_concat(path, bpf_map__name(map), buf);
+			if (err)
 				goto err_unpin_maps;
-			}
 			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
@@ -8009,14 +8012,9 @@  int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 		char buf[PATH_MAX];
 
 		if (path) {
-			int len;
-
-			len = snprintf(buf, PATH_MAX, "%s/%s", path,
-				       bpf_map__name(map));
-			if (len < 0)
-				return libbpf_err(-EINVAL);
-			else if (len >= PATH_MAX)
-				return libbpf_err(-ENAMETOOLONG);
+			err = pathname_concat(path, bpf_map__name(map), buf);
+			if (err)
+				return err;
 			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
@@ -8034,6 +8032,7 @@  int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 {
 	struct bpf_program *prog;
+	char buf[PATH_MAX];
 	int err;
 
 	if (!obj)
@@ -8045,17 +8044,9 @@  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 	}
 
 	bpf_object__for_each_program(prog, obj) {
-		char buf[PATH_MAX];
-		int len;
-
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0) {
-			err = -EINVAL;
-			goto err_unpin_programs;
-		} else if (len >= PATH_MAX) {
-			err = -ENAMETOOLONG;
+		err = pathname_concat(path, prog->name, buf);
+		if (err)
 			goto err_unpin_programs;
-		}
 
 		err = bpf_program__pin(prog, buf);
 		if (err)
@@ -8066,13 +8057,7 @@  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 
 err_unpin_programs:
 	while ((prog = bpf_object__prev_program(obj, prog))) {
-		char buf[PATH_MAX];
-		int len;
-
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0)
-			continue;
-		else if (len >= PATH_MAX)
+		if (pathname_concat(path, prog->name, buf))
 			continue;
 
 		bpf_program__unpin(prog, buf);
@@ -8091,13 +8076,10 @@  int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
 
 	bpf_object__for_each_program(prog, obj) {
 		char buf[PATH_MAX];
-		int len;
 
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0)
-			return libbpf_err(-EINVAL);
-		else if (len >= PATH_MAX)
-			return libbpf_err(-ENAMETOOLONG);
+		err = pathname_concat(path, prog->name, buf);
+		if (err)
+			return libbpf_err(err);
 
 		err = bpf_program__unpin(prog, buf);
 		if (err)