[v4,bpf-next,4/7] libbpf: add internal pin_name

Commit Message

Stanislav Fomichev Nov. 9, 2018, 12:22 a.m. UTC

From: Stanislav Fomichev <[e-mail]>

pin_name is the same as section_name where '/' is replaced
by '_'. bpf_object__pin_programs is converted to use pin_name
to avoid the situation where section_name would require creating another
subdirectory for a pin (as, for example, when calling bpf_object__pin_programs
for programs in sections like "cgroup/connect6").

Signed-off-by: Stanislav Fomichev <[e-mail]>
---
 tools/lib/bpf/libbpf.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

Comments

Jakub Kicinski Nov. 9, 2018, 3:38 a.m. UTC | #1

On Thu,  8 Nov 2018 16:22:10 -0800, Stanislav Fomichev wrote:
> @@ -261,6 +266,18 @@ static void bpf_program__exit(struct bpf_program *prog)
>  	prog->idx = -1;
>  }
>  
> +static char *__bpf_program__pin_name(struct bpf_program *prog)
> +{
> +	char *name;
> +
> +	name = strdup(prog->section_name);
> +	for (char *p = name; p && *p; p++)

Useful patch!  I'm not sure about libbpf but in the kernel we don't do
C99 variable declarations inside for loop init.  Perhaps better to stick
to kernel rules than invent our own.

Also, I'm tempted to say:

	char *name, *p;

	name = p = strdup(prog->section_name);
	while ((p = strchr(p, '/')))
		*p = '_';

;)

> +		if (*p == '/')
> +			*p = '_';
> +
> +	return name;
> +}

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index cfa269c91e11..38dbeb113eeb 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -124,6 +124,10 @@  struct bpf_program {
 	char *name;
 	int prog_ifindex;
 	char *section_name;
+	/* section_name with / replaced by _; makes recursive pinning
+	 * in bpf_object__pin_programs easier
+	 */
+	char *pin_name;
 	struct bpf_insn *insns;
 	size_t insns_cnt, main_prog_cnt;
 	enum bpf_prog_type type;
@@ -253,6 +257,7 @@  static void bpf_program__exit(struct bpf_program *prog)
 	bpf_program__unload(prog);
 	zfree(&prog->name);
 	zfree(&prog->section_name);
+	zfree(&prog->pin_name);
 	zfree(&prog->insns);
 	zfree(&prog->reloc_desc);
 
@@ -261,6 +266,18 @@  static void bpf_program__exit(struct bpf_program *prog)
 	prog->idx = -1;
 }
 
+static char *__bpf_program__pin_name(struct bpf_program *prog)
+{
+	char *name;
+
+	name = strdup(prog->section_name);
+	for (char *p = name; p && *p; p++)
+		if (*p == '/')
+			*p = '_';
+
+	return name;
+}
+
 static int
 bpf_program__init(void *data, size_t size, char *section_name, int idx,
 		  struct bpf_program *prog)
@@ -279,6 +296,13 @@  bpf_program__init(void *data, size_t size, char *section_name, int idx,
 		goto errout;
 	}
 
+	prog->pin_name = __bpf_program__pin_name(prog);
+	if (!prog->pin_name) {
+		pr_warning("failed to alloc pin name for prog under section(%d) %s\n",
+			   idx, section_name);
+		goto errout;
+	}
+
 	prog->insns = malloc(size);
 	if (!prog->insns) {
 		pr_warning("failed to alloc insns for prog under section %s\n",
@@ -2008,7 +2032,7 @@  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 		int len;
 
 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
-			       prog->section_name);
+			       prog->pin_name);
 		if (len < 0) {
 			err = -EINVAL;
 			goto err_unpin_programs;
@@ -2032,7 +2056,7 @@  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 		int len;
 
 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
-			       prog->section_name);
+			       prog->pin_name);
 		if (len < 0)
 			continue;
 		else if (len >= PATH_MAX)
@@ -2057,7 +2081,7 @@  int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
 		int len;
 
 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
-			       prog->section_name);
+			       prog->pin_name);
 		if (len < 0)
 			return -EINVAL;
 		else if (len >= PATH_MAX)