[PATCH net-next V3 0/3] tools: bpftool: show filenames of pinned objects

[PATCH net-next V3 0/3] tools: bpftool: show filenames of pinned objects

[Prashant Bhole]

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.

v1->v2:
 - Dynamically identify bpf-fs moutpoint
 - Close files descriptors before returning on error
 - Change command line option from {-l|--pinned} to {-f|--bpffs}
 - Updated documentation
 - Fixed line break for proper output formatting
 - Code style: wrapped lines > 80, used reverse christmastree style

v2->v3:
 - Handle multiple bpffs mountpoints
 - Code style: fixed line break indentation

Prashant Bhole (3):
  tools: bpftool: open pinned object without type check
  tools: bpftool: show filenames of pinned objects
  tools: bpftool: optionally show filenames of pinned objects

 tools/bpf/bpftool/Documentation/bpftool-map.rst  |   5 +-
 tools/bpf/bpftool/Documentation/bpftool-prog.rst |   5 +-
 tools/bpf/bpftool/common.c                       | 100 ++++++++++++++++++++++-
 tools/bpf/bpftool/main.c                         |  18 +++-
 tools/bpf/bpftool/main.h                         |  21 ++++-
 tools/bpf/bpftool/map.c                          |  22 +++++
 tools/bpf/bpftool/prog.c                         |  25 ++++++
 7 files changed, 190 insertions(+), 6 deletions(-)

-- 
2.13.6

[PATCH net-next V3 1/3] tools: bpftool: open pinned object without type check

[Prashant Bhole]

This was needed for opening any file in bpf-fs without knowing
its object type

Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
---
v2:
 - No change

v3:
 - No change

 tools/bpf/bpftool/common.c | 15 +++++++++++++--
 tools/bpf/bpftool/main.h   |  1 +
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index f0288269dae8..4556947709ee 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -91,9 +91,8 @@ 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);
@@ -105,6 +104,18 @@ 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);
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index d315d01be645..4b5685005cb0 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -86,6 +86,7 @@ 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));
 
-- 
2.13.6

[PATCH net-next V3 2/3] tools: bpftool: show filenames of pinned objects

[Prashant Bhole]

Added support to show filenames of pinned objects.

For example:

root@test# ./bpftool prog
3: tracepoint  name tracepoint__irq  tag f677a7dd722299a3
    loaded_at Oct 26/11:39  uid 0
    xlated 160B  not jited  memlock 4096B  map_ids 4
    pinned /sys/fs/bpf/softirq_prog

4: tracepoint  name tracepoint__irq  tag ea5dc530d00b92b6
    loaded_at Oct 26/11:39  uid 0
    xlated 392B  not jited  memlock 4096B  map_ids 4,6

root@test# ./bpftool --json --pretty prog
[{
        "id": 3,
        "type": "tracepoint",
        "name": "tracepoint__irq",
        "tag": "f677a7dd722299a3",
        "loaded_at": "Oct 26/11:39",
        "uid": 0,
        "bytes_xlated": 160,
        "jited": false,
        "bytes_memlock": 4096,
        "map_ids": [4
        ],
        "pinned": ["/sys/fs/bpf/softirq_prog"
        ]
    },{
        "id": 4,
        "type": "tracepoint",
        "name": "tracepoint__irq",
        "tag": "ea5dc530d00b92b6",
        "loaded_at": "Oct 26/11:39",
        "uid": 0,
        "bytes_xlated": 392,
        "jited": false,
        "bytes_memlock": 4096,
        "map_ids": [4,6
        ],
        "pinned": []
    }
]

root@test# ./bpftool map
4: hash  name start  flags 0x0
    key 4B  value 16B  max_entries 10240  memlock 1003520B
    pinned /sys/fs/bpf/softirq_map1
5: hash  name iptr  flags 0x0
    key 4B  value 8B  max_entries 10240  memlock 921600B

root@test# ./bpftool --json --pretty map
[{
        "id": 4,
        "type": "hash",
        "name": "start",
        "flags": 0,
        "bytes_key": 4,
        "bytes_value": 16,
        "max_entries": 10240,
        "bytes_memlock": 1003520,
        "pinned": ["/sys/fs/bpf/softirq_map1"
        ]
    },{
        "id": 5,
        "type": "hash",
        "name": "iptr",
        "flags": 0,
        "bytes_key": 4,
        "bytes_value": 8,
        "max_entries": 10240,
        "bytes_memlock": 921600,
        "pinned": []
    }
]

Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
---
v2:
 - Dynamically identify bpf-fs moutpoint
 - Close files descriptors before returning on error
 - Fixed line break for proper output formatting
 - Code style: wrapped lines > 80, used reverse christmastree style

v3:
 - Handle multiple bpffs mountpoints
 - Code style: fixed line break indentation

 tools/bpf/bpftool/common.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/bpf/bpftool/main.c   |  8 +++++
 tools/bpf/bpftool/main.h   | 17 ++++++++++
 tools/bpf/bpftool/map.c    | 21 ++++++++++++
 tools/bpf/bpftool/prog.c   | 24 +++++++++++++
 5 files changed, 155 insertions(+)

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 4556947709ee..152c5bdbe2e9 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -45,6 +45,8 @@
 #include <sys/mount.h>
 #include <sys/types.h>
 #include <sys/vfs.h>
+#include <mntent.h>
+#include <fts.h>
 
 #include <bpf.h>
 
@@ -290,3 +292,86 @@ 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 = {};
+	__u32 len = sizeof(pinned_info);
+	struct pinned_obj *obj_node = NULL;
+	enum bpf_obj_type objtype;
+	struct mntent *mntent = NULL;
+	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)) != NULL) {
+		char *path[] = {mntent->mnt_dir, 0};
+
+		if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
+			continue;
+
+		fts = fts_open(path, 0, NULL);
+		if (!fts)
+			continue;
+
+		while ((ftse = fts_read(fts)) != NULL) {
+			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;
+
+	if (hash_empty(tab->table))
+		return;
+
+	hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
+		hash_del(&obj->hash);
+		free(obj->path);
+		free(obj);
+	}
+}
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 78d9afb74ef4..6ad53f1797fa 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -54,6 +54,8 @@ static int (*last_do_help)(int argc, char **argv);
 json_writer_t *json_wtr;
 bool pretty_output;
 bool json_output;
+struct pinned_obj_table prog_table;
+struct pinned_obj_table map_table;
 
 void usage(void)
 {
@@ -272,6 +274,9 @@ int main(int argc, char **argv)
 	json_output = false;
 	bin_name = argv[0];
 
+	hash_init(prog_table.table);
+	hash_init(map_table.table);
+
 	while ((opt = getopt_long(argc, argv, "Vhpj",
 				  options, NULL)) >= 0) {
 		switch (opt) {
@@ -311,5 +316,8 @@ int main(int argc, char **argv)
 	if (json_output)
 		jsonw_destroy(&json_wtr);
 
+	delete_pinned_obj_table(&prog_table);
+	delete_pinned_obj_table(&map_table);
+
 	return ret;
 }
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 4b5685005cb0..726f6e27a706 100644
--- a/tools/bpf/bpftool/main.h
+++ b/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"
 
@@ -70,11 +71,27 @@ extern const char *bin_name;
 
 extern json_writer_t *json_wtr;
 extern bool json_output;
+extern struct pinned_obj_table prog_table;
+extern struct pinned_obj_table map_table;
 
 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);
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index e978ab23a77f..de0980657cef 100644
--- a/tools/bpf/bpftool/map.c
+++ b/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 +497,8 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
+	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)
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 250f80fd46aa..11375f669fc0 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -256,6 +256,18 @@ 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);
 }
 
@@ -300,6 +312,16 @@ 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");
 }
 
@@ -329,6 +351,8 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
+	build_pinned_obj_table(&prog_table, BPF_OBJ_PROG);
+
 	if (argc == 2) {
 		fd = prog_parse_fd(&argc, &argv);
 		if (fd < 0)
-- 
2.13.6

Re: [PATCH net-next V3 2/3] tools: bpftool: show filenames of pinned objects

[Jakub Kicinski]

On Mon,  6 Nov 2017 15:06:31 +0900, Prashant Bhole wrote:
> Added support to show filenames of pinned objects.
> ...
> Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>

Thanks for the changes, a couple more nit picks, sorry for not spotting
them earlier.

> v2:
>  - Dynamically identify bpf-fs moutpoint
>  - Close files descriptors before returning on error
>  - Fixed line break for proper output formatting
>  - Code style: wrapped lines > 80, used reverse christmastree style
> 
> v3:
>  - Handle multiple bpffs mountpoints
>  - Code style: fixed line break indentation
> 
>  tools/bpf/bpftool/common.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++
>  tools/bpf/bpftool/main.c   |  8 +++++
>  tools/bpf/bpftool/main.h   | 17 ++++++++++
>  tools/bpf/bpftool/map.c    | 21 ++++++++++++
>  tools/bpf/bpftool/prog.c   | 24 +++++++++++++
>  5 files changed, 155 insertions(+)
> 
> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> index 4556947709ee..152c5bdbe2e9 100644
> --- a/tools/bpf/bpftool/common.c
> +++ b/tools/bpf/bpftool/common.c
> @@ -45,6 +45,8 @@
>  #include <sys/mount.h>
>  #include <sys/types.h>
>  #include <sys/vfs.h>
> +#include <mntent.h>
> +#include <fts.h>

Please try to keep includes in an alphabetical order.

>  #include <bpf.h>
>  
> @@ -290,3 +292,86 @@ 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 = {};
> +	__u32 len = sizeof(pinned_info);
> +	struct pinned_obj *obj_node = NULL;
> +	enum bpf_obj_type objtype;
> +	struct mntent *mntent = NULL;

Please try to order variable declarations longest to shortest.

> +	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)) != NULL) {

Please try to avoid comparisons to NULL, writing:

	if (ptr)

is more intuitive to most C programmers than:

	if (ptr != NULL)

> +		char *path[] = {mntent->mnt_dir, 0};

Shouldn't there be spaces after and before the curly braces?  Does
checkpatch --strict not warn about this?

> +
> +		if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
> +			continue;
> +
> +		fts = fts_open(path, 0, NULL);
> +		if (!fts)
> +			continue;
> +
> +		while ((ftse = fts_read(fts)) != NULL) {
> +			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;
> +
> +	if (hash_empty(tab->table))
> +		return;

is this necessary?  Does hash_for_each_safe() not work with empty table?

> +	hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
> +		hash_del(&obj->hash);
> +		free(obj->path);
> +		free(obj);
> +	}
> +}

RE: [PATCH net-next V3 2/3] tools: bpftool: show filenames of pinned objects

[Prashant Bhole]

> -----Original Message-----
> From: Jakub Kicinski [mailto:jakub.kicinski@netronome.com]
> 
> On Mon,  6 Nov 2017 15:06:31 +0900, Prashant Bhole wrote:
> > Added support to show filenames of pinned objects.
> > ...
> > Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
> 
> Thanks for the changes, a couple more nit picks, sorry for not spotting
them
> earlier.
> 
> > v2:
> >  - Dynamically identify bpf-fs moutpoint
> >  - Close files descriptors before returning on error
> >  - Fixed line break for proper output formatting
> >  - Code style: wrapped lines > 80, used reverse christmastree style
> >
> > v3:
> >  - Handle multiple bpffs mountpoints
> >  - Code style: fixed line break indentation
> >
> >  tools/bpf/bpftool/common.c | 85
> ++++++++++++++++++++++++++++++++++++++++++++++
> >  tools/bpf/bpftool/main.c   |  8 +++++
> >  tools/bpf/bpftool/main.h   | 17 ++++++++++
> >  tools/bpf/bpftool/map.c    | 21 ++++++++++++
> >  tools/bpf/bpftool/prog.c   | 24 +++++++++++++
> >  5 files changed, 155 insertions(+)
> >
> > diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> > index 4556947709ee..152c5bdbe2e9 100644
> > --- a/tools/bpf/bpftool/common.c
> > +++ b/tools/bpf/bpftool/common.c
> > @@ -45,6 +45,8 @@
> >  #include <sys/mount.h>
> >  #include <sys/types.h>
> >  #include <sys/vfs.h>
> > +#include <mntent.h>
> > +#include <fts.h>
> 
> Please try to keep includes in an alphabetical order.
> 
> >  #include <bpf.h>
> >
> > @@ -290,3 +292,86 @@ 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 = {};
> > +	__u32 len = sizeof(pinned_info);
> > +	struct pinned_obj *obj_node = NULL;
> > +	enum bpf_obj_type objtype;
> > +	struct mntent *mntent = NULL;
> 
> Please try to order variable declarations longest to shortest.
> 
> > +	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)) != NULL) {
> 
> Please try to avoid comparisons to NULL, writing:
> 
> 	if (ptr)
> 
> is more intuitive to most C programmers than:
> 
> 	if (ptr != NULL)

Jakub,
Thank you for comments. I agree with using 'if (ptr)' for simple check, but
here it is an assignment.
It doesn't look intuitive and looks like a typo if I change it to:
         while ((mntent = getmntent(mntfile))) {

> 
> > +		char *path[] = {mntent->mnt_dir, 0};
> 
> Shouldn't there be spaces after and before the curly braces?  Does
checkpatch --
> strict not warn about this?

I will add spaces. checkpatch complained about this not being static const,
but doing so causes compiler warning because it doesn't match with signature
of fts_open()

I will submit v4 with changes for other comments if you are ok with replies
above.

Prashant

Re: [PATCH net-next V3 2/3] tools: bpftool: show filenames of pinned objects

[Jakub Kicinski]

On Wed, 8 Nov 2017 11:34:44 +0900, Prashant Bhole wrote:
> > > +	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)) != NULL) {  
> > 
> > Please try to avoid comparisons to NULL, writing:
> > 
> > 	if (ptr)
> > 
> > is more intuitive to most C programmers than:
> > 
> > 	if (ptr != NULL)  
> 
> Jakub,
> Thank you for comments. I agree with using 'if (ptr)' for simple check, but
> here it is an assignment.
> It doesn't look intuitive and looks like a typo if I change it to:
>          while ((mntent = getmntent(mntfile))) {

I still prefer this, if you don't mind.

> >   
> > > +		char *path[] = {mntent->mnt_dir, 0};  
> > 
> > Shouldn't there be spaces after and before the curly braces?  Does  
> checkpatch --
> > strict not warn about this?  
> 
> I will add spaces. checkpatch complained about this not being static const,
> but doing so causes compiler warning because it doesn't match with signature
> of fts_open()

Right, that's OK to ignore.  Could you also make the 0 into a NULL,
though?

> I will submit v4 with changes for other comments if you are ok with replies
> above.

Thank you!

[PATCH net-next V3 3/3] tools: bpftool: optionally show filenames of pinned objects

[Prashant Bhole]

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>
---
v2:
 - Change command line option from {-l|--pinned} to {-f|--bpffs}
 - Updated documentation

v3:
 - No change

 tools/bpf/bpftool/Documentation/bpftool-map.rst  |  5 ++++-
 tools/bpf/bpftool/Documentation/bpftool-prog.rst |  5 ++++-
 tools/bpf/bpftool/main.c                         | 14 +++++++++++---
 tools/bpf/bpftool/main.h                         |  3 ++-
 tools/bpf/bpftool/map.c                          |  3 ++-
 tools/bpf/bpftool/prog.c                         |  3 ++-
 6 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
index abb9ee940b15..9f51a268eb06 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
+++ b/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**
diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index 0f25d3c39e05..36e8d1c3c40d 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/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**
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 6ad53f1797fa..d6e4762170a4 100644
--- a/tools/bpf/bpftool/main.c
+++ b/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);
 
-	delete_pinned_obj_table(&prog_table);
-	delete_pinned_obj_table(&map_table);
+	if (show_pinned) {
+		delete_pinned_obj_table(&prog_table);
+		delete_pinned_obj_table(&map_table);
+	}
 
 	return ret;
 }
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 726f6e27a706..32846a0e42fb 100644
--- a/tools/bpf/bpftool/main.h
+++ b/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;
 
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index de0980657cef..e2450c8e88e6 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -497,7 +497,8 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
-	build_pinned_obj_table(&map_table, BPF_OBJ_MAP);
+	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);
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 11375f669fc0..ad619b96c276 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -351,7 +351,8 @@ static int do_show(int argc, char **argv)
 	int err;
 	int fd;
 
-	build_pinned_obj_table(&prog_table, BPF_OBJ_PROG);
+	if (show_pinned)
+		build_pinned_obj_table(&prog_table, BPF_OBJ_PROG);
 
 	if (argc == 2) {
 		fd = prog_parse_fd(&argc, &argv);
-- 
2.13.6

Re: [PATCH net-next V3 0/3] tools: bpftool: show filenames of pinned objects

[Quentin Monnet]

2017-11-06 15:06 UTC+0900 ~ Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
> 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.
> 
> v1->v2:
>  - Dynamically identify bpf-fs moutpoint
>  - Close files descriptors before returning on error
>  - Change command line option from {-l|--pinned} to {-f|--bpffs}
>  - Updated documentation
>  - Fixed line break for proper output formatting
>  - Code style: wrapped lines > 80, used reverse christmastree style
> 
> v2->v3:
>  - Handle multiple bpffs mountpoints
>  - Code style: fixed line break indentation
> 

Thanks for the changes! This version looks good to me.

Acked-by: Quentin Monnet <quentin.monnet@netronome.com>