Merge branch 'bpftool-show-filenames-of-pinned-objects'

Prashant Bhole says:

====================
tools: bpftool: show filenames of pinned objects

This patchset adds support to show pinned objects in object details.

Patch1 adds a funtionality to open a path in bpf-fs regardless of its object
type.

Patch2 adds actual functionality by scanning the bpf-fs once and adding
object information in hash table, with object id as a key. One object may be
associated with multiple paths because an object can be pinned multiple times

Patch3 adds command line option to enable this functionality. Making it optional
because scanning bpf-fs can be costly.
====================

Acked-by: Jakub Kicinski <[email protected]>

tools/bpf/bpftool/Documentation/bpftool-map.rst

@@ -12,7 +12,7 @@ SYNOPSIS
 
 	**bpftool** [*OPTIONS*] **map** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
+	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
 
 	*COMMANDS* :=
 	{ **show** | **dump** | **update** | **lookup** | **getnext** | **delete**
@@ -86,6 +86,9 @@ OPTIONS
 	-p, --pretty
 		  Generate human-readable JSON output. Implies **-j**.
 
+	-f, --bpffs
+		  Show file names of pinned maps.
+
 EXAMPLES
 ========
 **# bpftool map show**

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -12,7 +12,7 @@ SYNOPSIS
 
 	**bpftool** [*OPTIONS*] **prog** *COMMAND*
 
-	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
+	*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
 
 	*COMMANDS* :=
 	{ **show** | **dump xlated** | **dump jited** | **pin** | **help** }
@@ -75,6 +75,9 @@ OPTIONS
 	-p, --pretty
 		  Generate human-readable JSON output. Implies **-j**.
 
+	-f, --bpffs
+		  Show file names of pinned programs.
+
 EXAMPLES
 ========
 **# bpftool prog show**

tools/bpf/bpftool/common.c

@@ -34,7 +34,9 @@
 /* Author: Jakub Kicinski <[email protected]> */
 
 #include <errno.h>
+#include <fts.h>
 #include <libgen.h>
+#include <mntent.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -122,9 +124,8 @@ static int mnt_bpffs(const char *target, char *buff, size_t bufflen)
 	return 0;
 }
 
-int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
+int open_obj_pinned(char *path)
 {
-	enum bpf_obj_type type;
 	int fd;
 
 	fd = bpf_obj_get(path);
@@ -136,6 +137,18 @@ int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
 		return -1;
 	}
 
+	return fd;
+}
+
+int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
+{
+	enum bpf_obj_type type;
+	int fd;
+
+	fd = open_obj_pinned(path);
+	if (fd < 0)
+		return -1;
+
 	type = get_fd_type(fd);
 	if (type < 0) {
 		close(fd);
@@ -310,3 +323,83 @@ void print_hex_data_json(uint8_t *data, size_t len)
 		jsonw_printf(json_wtr, "\"0x%02hhx\"", data[i]);
 	jsonw_end_array(json_wtr);
 }
+
+int build_pinned_obj_table(struct pinned_obj_table *tab,
+			   enum bpf_obj_type type)
+{
+	struct bpf_prog_info pinned_info = {};
+	struct pinned_obj *obj_node = NULL;
+	__u32 len = sizeof(pinned_info);
+	struct mntent *mntent = NULL;
+	enum bpf_obj_type objtype;
+	FILE *mntfile = NULL;
+	FTSENT *ftse = NULL;
+	FTS *fts = NULL;
+	int fd, err;
+
+	mntfile = setmntent("/proc/mounts", "r");
+	if (!mntfile)
+		return -1;
+
+	while ((mntent = getmntent(mntfile))) {
+		char *path[] = { mntent->mnt_dir, NULL };
+
+		if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
+			continue;
+
+		fts = fts_open(path, 0, NULL);
+		if (!fts)
+			continue;
+
+		while ((ftse = fts_read(fts))) {
+			if (!(ftse->fts_info & FTS_F))
+				continue;
+			fd = open_obj_pinned(ftse->fts_path);
+			if (fd < 0)
+				continue;
+
+			objtype = get_fd_type(fd);
+			if (objtype != type) {
+				close(fd);
+				continue;
+			}
+			memset(&pinned_info, 0, sizeof(pinned_info));
+			err = bpf_obj_get_info_by_fd(fd, &pinned_info, &len);
+			if (err) {
+				close(fd);
+				continue;
+			}
+
+			obj_node = malloc(sizeof(*obj_node));
+			if (!obj_node) {
+				close(fd);
+				fts_close(fts);
+				fclose(mntfile);
+				return -1;
+			}
+
+			memset(obj_node, 0, sizeof(*obj_node));
+			obj_node->id = pinned_info.id;
+			obj_node->path = strdup(ftse->fts_path);
+			hash_add(tab->table, &obj_node->hash, obj_node->id);
+
+			close(fd);
+		}
+		fts_close(fts);
+	}
+	fclose(mntfile);
+	return 0;
+}
+
+void delete_pinned_obj_table(struct pinned_obj_table *tab)
+{
+	struct pinned_obj *obj;
+	struct hlist_node *tmp;
+	unsigned int bkt;
+
+	hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
+		hash_del(&obj->hash);
+		free(obj->path);
+		free(obj);
+	}
+}

tools/bpf/bpftool/main.c

@@ -54,6 +54,9 @@ static int (*last_do_help)(int argc, char **argv);
 json_writer_t *json_wtr;
 bool pretty_output;
 bool json_output;
+bool show_pinned;
+struct pinned_obj_table prog_table;
+struct pinned_obj_table map_table;
 
 void usage(void)
 {
@@ -263,16 +266,21 @@ int main(int argc, char **argv)
 		{ "help",	no_argument,	NULL,	'h' },
 		{ "pretty",	no_argument,	NULL,	'p' },
 		{ "version",	no_argument,	NULL,	'V' },
+		{ "bpffs",	no_argument,	NULL,	'f' },
 		{ 0 }
 	};
 	int opt, ret;
 
 	last_do_help = do_help;
 	pretty_output = false;
 	json_output = false;
+	show_pinned = false;
 	bin_name = argv[0];
 
-	while ((opt = getopt_long(argc, argv, "Vhpj",
+	hash_init(prog_table.table);
+	hash_init(map_table.table);
+
+	while ((opt = getopt_long(argc, argv, "Vhpjf",
 				  options, NULL)) >= 0) {
 		switch (opt) {
 		case 'V':
@@ -285,6 +293,9 @@ int main(int argc, char **argv)
 		case 'j':
 			json_output = true;
 			break;
+		case 'f':
+			show_pinned = true;
+			break;
 		default:
 			usage();
 		}
@@ -311,5 +322,10 @@ int main(int argc, char **argv)
 	if (json_output)
 		jsonw_destroy(&json_wtr);
 
+	if (show_pinned) {
+		delete_pinned_obj_table(&prog_table);
+		delete_pinned_obj_table(&map_table);
+	}
+
 	return ret;
 }

tools/bpf/bpftool/main.h

@@ -42,6 +42,7 @@
 #include <stdio.h>
 #include <linux/bpf.h>
 #include <linux/kernel.h>
+#include <linux/hashtable.h>
 
 #include "json_writer.h"
 
@@ -58,7 +59,7 @@
 #define HELP_SPEC_PROGRAM						\
 	"PROG := { id PROG_ID | pinned FILE | tag PROG_TAG }"
 #define HELP_SPEC_OPTIONS						\
-	"OPTIONS := { {-j|--json} [{-p|--pretty}] }"
+	"OPTIONS := { {-j|--json} [{-p|--pretty}] | {-f|--bpffs} }"
 
 enum bpf_obj_type {
 	BPF_OBJ_UNKNOWN,
@@ -70,6 +71,9 @@ extern const char *bin_name;
 
 extern json_writer_t *json_wtr;
 extern bool json_output;
+extern bool show_pinned;
+extern struct pinned_obj_table prog_table;
+extern struct pinned_obj_table map_table;
 
 void p_err(const char *fmt, ...);
 void p_info(const char *fmt, ...);
@@ -78,6 +82,20 @@ bool is_prefix(const char *pfx, const char *str);
 void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep);
 void usage(void) __attribute__((noreturn));
 
+struct pinned_obj_table {
+	DECLARE_HASHTABLE(table, 16);
+};
+
+struct pinned_obj {
+	__u32 id;
+	char *path;
+	struct hlist_node hash;
+};
+
+int build_pinned_obj_table(struct pinned_obj_table *table,
+			   enum bpf_obj_type type);
+void delete_pinned_obj_table(struct pinned_obj_table *tab);
+
 struct cmd {
 	const char *cmd;
 	int (*func)(int argc, char **argv);
@@ -89,6 +107,7 @@ int cmd_select(const struct cmd *cmds, int argc, char **argv,
 int get_fd_type(int fd);
 const char *get_fd_type_name(enum bpf_obj_type type);
 char *get_fdinfo(int fd, const char *key);
+int open_obj_pinned(char *path);
 int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type);
 int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32));
 

tools/bpf/bpftool/map.c

@@ -436,6 +436,18 @@ static int show_map_close_json(int fd, struct bpf_map_info *info)
 		jsonw_int_field(json_wtr, "bytes_memlock", atoi(memlock));
 	free(memlock);
 
+	if (!hash_empty(map_table.table)) {
+		struct pinned_obj *obj;
+
+		jsonw_name(json_wtr, "pinned");
+		jsonw_start_array(json_wtr);
+		hash_for_each_possible(map_table.table, obj, hash, info->id) {
+			if (obj->id == info->id)
+				jsonw_string(json_wtr, obj->path);
+		}
+		jsonw_end_array(json_wtr);
+	}
+
 	jsonw_end_object(json_wtr);
 
 	return 0;
@@ -466,7 +478,14 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info)
 	free(memlock);
 
 	printf("\n");
+	if (!hash_empty(map_table.table)) {
+		struct pinned_obj *obj;
 
+		hash_for_each_possible(map_table.table, obj, hash, info->id) {
+			if (obj->id == info->id)
+				printf("\tpinned %s\n", obj->path);
+		}
+	}
 	return 0;
 }
 
@@ -478,6 +497,9 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
+	if (show_pinned)
+		build_pinned_obj_table(&map_table, BPF_OBJ_MAP);
+
 	if (argc == 2) {
 		fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
 		if (fd < 0)

tools/bpf/bpftool/prog.c

@@ -272,6 +272,18 @@ static void print_prog_json(struct bpf_prog_info *info, int fd)
 	if (info->nr_map_ids)
 		show_prog_maps(fd, info->nr_map_ids);
 
+	if (!hash_empty(prog_table.table)) {
+		struct pinned_obj *obj;
+
+		jsonw_name(json_wtr, "pinned");
+		jsonw_start_array(json_wtr);
+		hash_for_each_possible(prog_table.table, obj, hash, info->id) {
+			if (obj->id == info->id)
+				jsonw_string(json_wtr, obj->path);
+		}
+		jsonw_end_array(json_wtr);
+	}
+
 	jsonw_end_object(json_wtr);
 }
 
@@ -331,6 +343,16 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd)
 	if (info->nr_map_ids)
 		show_prog_maps(fd, info->nr_map_ids);
 
+	if (!hash_empty(prog_table.table)) {
+		struct pinned_obj *obj;
+
+		printf("\n");
+		hash_for_each_possible(prog_table.table, obj, hash, info->id) {
+			if (obj->id == info->id)
+				printf("\tpinned %s\n", obj->path);
+		}
+	}
+
 	printf("\n");
 }
 
@@ -360,6 +382,9 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
+	if (show_pinned)
+		build_pinned_obj_table(&prog_table, BPF_OBJ_PROG);
+
 	if (argc == 2) {
 		fd = prog_parse_fd(&argc, &argv);
 		if (fd < 0)