tools: bpftool: optionally show filenames of pinned objects

Making it optional to show file names of pinned objects because
it scans complete bpf-fs filesystem which is costly.
Added option -f|--bpffs. Documentation updated.
Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

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/main.c

@@ -54,6 +54,7 @@ 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;
 
@@ -265,6 +266,7 @@ 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;
@@ -272,12 +274,13 @@ int main(int argc, char **argv)
 	last_do_help = do_help;
 	pretty_output = false;
 	json_output = false;
+	show_pinned = false;
 	bin_name = argv[0];
 
 	hash_init(prog_table.table);
 	hash_init(map_table.table);
 
-	while ((opt = getopt_long(argc, argv, "Vhpj",
+	while ((opt = getopt_long(argc, argv, "Vhpjf",
 				  options, NULL)) >= 0) {
 		switch (opt) {
 		case 'V':
@@ -290,6 +293,9 @@ int main(int argc, char **argv)
 		case 'j':
 			json_output = true;
 			break;
+		case 'f':
+			show_pinned = true;
+			break;
 		default:
 			usage();
 		}
@@ -316,8 +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

@@ -59,7 +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,
@@ -71,6 +71,7 @@ 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;
 

tools/bpf/bpftool/map.c

@@ -497,6 +497,7 @@ 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) {

tools/bpf/bpftool/prog.c

@@ -382,6 +382,7 @@ 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) {