Merge branch 'bpf-bpftool-queue-stack'

Stanislav Fomichev says:

====================
This patch series add support for queue/stack manipulations.

It goes like this:

commands by permitting empty keys.

v2:
* removed unneeded jsonw_null from patch #6
* improved bash completions (and moved them into separate patch #7)
====================

Reviewed-by: Jakub Kicinski <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>

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

···
 |	**bpftool** **map create**     *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* \
 |		**entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*]
 |	**bpftool** **map dump**       *MAP*
-|	**bpftool** **map update**     *MAP*  **key** *DATA*   **value** *VALUE* [*UPDATE_FLAGS*]
-|	**bpftool** **map lookup**     *MAP*  **key** *DATA*
+|	**bpftool** **map update**     *MAP* [**key** *DATA*] [**value** *VALUE*] [*UPDATE_FLAGS*]
+|	**bpftool** **map lookup**     *MAP* [**key** *DATA*]
 |	**bpftool** **map getnext**    *MAP* [**key** *DATA*]
 |	**bpftool** **map delete**     *MAP*  **key** *DATA*
 |	**bpftool** **map pin**        *MAP*  *FILE*
 |	**bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
+|	**bpftool** **map peek**       *MAP*
+|	**bpftool** **map push**       *MAP* **value** *VALUE*
+|	**bpftool** **map pop**        *MAP*
+|	**bpftool** **map enqueue**    *MAP* **value** *VALUE*
+|	**bpftool** **map dequeue**    *MAP*
 |	**bpftool** **map help**
 |
 |	*MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
···
 	**bpftool map dump**    *MAP*
 		  Dump all entries in a given *MAP*.
 
-	**bpftool map update**  *MAP*  **key** *DATA*   **value** *VALUE* [*UPDATE_FLAGS*]
+	**bpftool map update**  *MAP* [**key** *DATA*] [**value** *VALUE*] [*UPDATE_FLAGS*]
 		  Update map entry for a given *KEY*.
 
 		  *UPDATE_FLAGS* can be one of: **any** update existing entry
···
 		  the bytes are parsed as decimal values, unless a "0x" prefix
 		  (for hexadecimal) or a "0" prefix (for octal) is provided.
 
-	**bpftool map lookup**  *MAP*  **key** *DATA*
+	**bpftool map lookup**  *MAP* [**key** *DATA*]
 		  Lookup **key** in the map.
 
 	**bpftool map getnext** *MAP* [**key** *DATA*]
···
 		  Note that installing a perf ring into an array will silently
 		  replace any existing ring.  Any other application will stop
 		  receiving events if it installed its rings earlier.
+
+	**bpftool map peek**  *MAP*
+		  Peek next **value** in the queue or stack.
+
+	**bpftool map push**  *MAP* **value** *VALUE*
+		  Push **value** onto the stack.
+
+	**bpftool map pop**  *MAP*
+		  Pop and print **value** from the stack.
+
+	**bpftool map enqueue**  *MAP* **value** *VALUE*
+		  Enqueue **value** into the queue.
+
+	**bpftool map dequeue**  *MAP*
+		  Dequeue and print **value** from the queue.
 
 	**bpftool map help**
 		  Print short help message.

tools/bpf/bpftool/bash-completion/bpftool

···
         command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) )
 }
 
-_bpftool_get_perf_map_ids()
+# Takes map type and adds matching map ids to the list of suggestions.
+_bpftool_get_map_ids_for_type()
 {
+    local type="$1"
     COMPREPLY+=( $( compgen -W "$( bpftool -jp map  2>&1 | \
-        command grep -C2 perf_event_array | \
+        command grep -C2 "$type" | \
         command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) )
 }
-
 
 _bpftool_get_prog_ids()
 {
···
         "$cur" ) )
 }
 
-# For bpftool map update: retrieve type of the map to update.
-_bpftool_map_update_map_type()
+# Retrieve type of the map that we are operating on.
+_bpftool_map_guess_map_type()
 {
     local keyword ref
     for (( idx=3; idx < ${#words[@]}-1; idx++ )); do
-        if [[ ${words[$((idx-2))]} == "update" ]]; then
-            keyword=${words[$((idx-1))]}
-            ref=${words[$((idx))]}
-        fi
+        case "${words[$((idx-2))]}" in
+            lookup|update)
+                keyword=${words[$((idx-1))]}
+                ref=${words[$((idx))]}
+                ;;
+            push)
+                printf "stack"
+                return 0
+                ;;
+            enqueue)
+                printf "queue"
+                return 0
+                ;;
+        esac
     done
     [[ -z $ref ]] && return 0
 
···
 
 _bpftool_map_update_get_id()
 {
+    local command="$1"
+
     # Is it the map to update, or a map to insert into the map to update?
     # Search for "value" keyword.
     local idx value
···
             break
         fi
     done
-    [[ $value -eq 0 ]] && _bpftool_get_map_ids && return 0
+    if [[ $value -eq 0 ]]; then
+        case "$command" in
+            push)
+                _bpftool_get_map_ids_for_type stack
+                ;;
+            enqueue)
+                _bpftool_get_map_ids_for_type queue
+                ;;
+            *)
+                _bpftool_get_map_ids
+                ;;
+        esac
+        return 0
+    fi
 
     # Id to complete is for a value. It can be either prog id or map id. This
     # depends on the type of the map to update.
-    local type=$(_bpftool_map_update_map_type)
+    local type=$(_bpftool_map_guess_map_type)
     case $type in
         array_of_maps|hash_of_maps)
             _bpftool_get_map_ids
···
         map)
             local MAP_TYPE='id pinned'
             case $command in
-                show|list|dump)
+                show|list|dump|peek|pop|dequeue)
                     case $prev in
                         $command)
                             COMPREPLY=( $( compgen -W "$MAP_TYPE" -- "$cur" ) )
                             return 0
                             ;;
                         id)
-                            _bpftool_get_map_ids
+                            case "$command" in
+                                peek)
+                                    _bpftool_get_map_ids_for_type stack
+                                    _bpftool_get_map_ids_for_type queue
+                                    ;;
+                                pop)
+                                    _bpftool_get_map_ids_for_type stack
+                                    ;;
+                                dequeue)
+                                    _bpftool_get_map_ids_for_type queue
+                                    ;;
+                                *)
+                                    _bpftool_get_map_ids
+                                    ;;
+                            esac
                             return 0
                             ;;
                         *)
···
                             COMPREPLY+=( $( compgen -W 'hex' -- "$cur" ) )
                             ;;
                         *)
+                            case $(_bpftool_map_guess_map_type) in
+                                queue|stack)
+                                    return 0
+                                    ;;
+                            esac
+
                             _bpftool_once_attr 'key'
                             return 0
                             ;;
                     esac
                     ;;
-                update)
+                update|push|enqueue)
                     case $prev in
                         $command)
                             COMPREPLY=( $( compgen -W "$MAP_TYPE" -- "$cur" ) )
                             return 0
                             ;;
                         id)
-                            _bpftool_map_update_get_id
+                            _bpftool_map_update_get_id $command
                             return 0
                             ;;
                         key)
···
                         value)
                             # We can have bytes, or references to a prog or a
                             # map, depending on the type of the map to update.
-                            case $(_bpftool_map_update_map_type) in
+                            case "$(_bpftool_map_guess_map_type)" in
                                 array_of_maps|hash_of_maps)
                                     local MAP_TYPE='id pinned'
                                     COMPREPLY+=( $( compgen -W "$MAP_TYPE" \
···
                             return 0
                             ;;
                         *)
+                            case $(_bpftool_map_guess_map_type) in
+                                queue|stack)
+                                    _bpftool_once_attr 'value'
+                                    return 0;
+                                    ;;
+                            esac
+
                             _bpftool_once_attr 'key'
                             local UPDATE_FLAGS='any exist noexist'
                             for (( idx=3; idx < ${#words[@]}-1; idx++ )); do
···
                                     return 0
                                 fi
                             done
+
                             return 0
                             ;;
                     esac
···
                             return 0
                             ;;
                         id)
-                            _bpftool_get_perf_map_ids
+                            _bpftool_get_map_ids_for_type perf_event_array
                             return 0
                             ;;
                         cpu)
···
                 *)
                     [[ $prev == $object ]] && \
                         COMPREPLY=( $( compgen -W 'delete dump getnext help \
-                            lookup pin event_pipe show list update create' -- \
+                            lookup pin event_pipe show list update create \
+                            peek push enqueue pop dequeue' -- \
                             "$cur" ) )
                     ;;
             esac

tools/bpf/bpftool/map.c

···
 		single_line = info->key_size + info->value_size <= 24 &&
 			!break_names;
 
-		printf("key:%c", break_names ? '\n' : ' ');
-		fprint_hex(stdout, key, info->key_size, " ");
+		if (info->key_size) {
+			printf("key:%c", break_names ? '\n' : ' ');
+			fprint_hex(stdout, key, info->key_size, " ");
 
-		printf(single_line ? "  " : "\n");
+			printf(single_line ? "  " : "\n");
+		}
 
-		printf("value:%c", break_names ? '\n' : ' ');
-		if (value)
-			fprint_hex(stdout, value, info->value_size, " ");
-		else
-			printf("<no entry>");
+		if (info->value_size) {
+			printf("value:%c", break_names ? '\n' : ' ');
+			if (value)
+				fprint_hex(stdout, value, info->value_size,
+					   " ");
+			else
+				printf("<no entry>");
+		}
 
 		printf("\n");
 	} else {
···
 		n = get_possible_cpus();
 		step = round_up(info->value_size, 8);
 
-		printf("key:\n");
-		fprint_hex(stdout, key, info->key_size, " ");
-		printf("\n");
-		for (i = 0; i < n; i++) {
-			printf("value (CPU %02d):%c",
-			       i, info->value_size > 16 ? '\n' : ' ');
-			if (value)
-				fprint_hex(stdout, value + i * step,
-					   info->value_size, " ");
-			else
-				printf("<no entry>");
+		if (info->key_size) {
+			printf("key:\n");
+			fprint_hex(stdout, key, info->key_size, " ");
 			printf("\n");
+		}
+		if (info->value_size) {
+			for (i = 0; i < n; i++) {
+				printf("value (CPU %02d):%c",
+				       i, info->value_size > 16 ? '\n' : ' ');
+				if (value)
+					fprint_hex(stdout, value + i * step,
+						   info->value_size, " ");
+				else
+					printf("<no entry>");
+				printf("\n");
+			}
 		}
 	}
 }
···
 	return err;
 }
 
+static int alloc_key_value(struct bpf_map_info *info, void **key, void **value)
+{
+	*key = NULL;
+	*value = NULL;
+
+	if (info->key_size) {
+		*key = malloc(info->key_size);
+		if (!*key) {
+			p_err("key mem alloc failed");
+			return -1;
+		}
+	}
+
+	if (info->value_size) {
+		*value = alloc_value(info);
+		if (!*value) {
+			p_err("value mem alloc failed");
+			free(*key);
+			*key = NULL;
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 static int do_update(int argc, char **argv)
 {
 	struct bpf_map_info info = {};
···
 	if (fd < 0)
 		return -1;
 
-	key = malloc(info.key_size);
-	value = alloc_value(&info);
-	if (!key || !value) {
-		p_err("mem alloc failed");
-		err = -1;
+	err = alloc_key_value(&info, &key, &value);
+	if (err)
 		goto exit_free;
-	}
 
 	err = parse_elem(argv, &info, key, value, info.key_size,
 			 info.value_size, &flags, &value_fd);
···
 	return err;
 }
 
+static void print_key_value(struct bpf_map_info *info, void *key,
+			    void *value)
+{
+	json_writer_t *btf_wtr;
+	struct btf *btf = NULL;
+	int err;
+
+	err = btf__get_from_id(info->btf_id, &btf);
+	if (err) {
+		p_err("failed to get btf");
+		return;
+	}
+
+	if (json_output) {
+		print_entry_json(info, key, value, btf);
+	} else if (btf) {
+		/* if here json_wtr wouldn't have been initialised,
+		 * so let's create separate writer for btf
+		 */
+		btf_wtr = get_btf_writer();
+		if (!btf_wtr) {
+			p_info("failed to create json writer for btf. falling back to plain output");
+			btf__free(btf);
+			btf = NULL;
+			print_entry_plain(info, key, value);
+		} else {
+			struct btf_dumper d = {
+				.btf = btf,
+				.jw = btf_wtr,
+				.is_plain_text = true,
+			};
+
+			do_dump_btf(&d, info, key, value);
+			jsonw_destroy(&btf_wtr);
+		}
+	} else {
+		print_entry_plain(info, key, value);
+	}
+	btf__free(btf);
+}
+
 static int do_lookup(int argc, char **argv)
 {
 	struct bpf_map_info info = {};
 	__u32 len = sizeof(info);
-	json_writer_t *btf_wtr;
-	struct btf *btf = NULL;
 	void *key, *value;
 	int err;
 	int fd;
···
 	if (fd < 0)
 		return -1;
 
-	key = malloc(info.key_size);
-	value = alloc_value(&info);
-	if (!key || !value) {
-		p_err("mem alloc failed");
-		err = -1;
+	err = alloc_key_value(&info, &key, &value);
+	if (err)
 		goto exit_free;
-	}
 
 	err = parse_elem(argv, &info, key, NULL, info.key_size, 0, NULL, NULL);
 	if (err)
···
 	}
 
 	/* here means bpf_map_lookup_elem() succeeded */
-	err = btf__get_from_id(info.btf_id, &btf);
-	if (err) {
-		p_err("failed to get btf");
-		goto exit_free;
-	}
-
-	if (json_output) {
-		print_entry_json(&info, key, value, btf);
-	} else if (btf) {
-		/* if here json_wtr wouldn't have been initialised,
-		 * so let's create separate writer for btf
-		 */
-		btf_wtr = get_btf_writer();
-		if (!btf_wtr) {
-			p_info("failed to create json writer for btf. falling back to plain output");
-			btf__free(btf);
-			btf = NULL;
-			print_entry_plain(&info, key, value);
-		} else {
-			struct btf_dumper d = {
-				.btf = btf,
-				.jw = btf_wtr,
-				.is_plain_text = true,
-			};
-
-			do_dump_btf(&d, &info, key, value);
-			jsonw_destroy(&btf_wtr);
-		}
-	} else {
-		print_entry_plain(&info, key, value);
-	}
+	print_key_value(&info, key, value);
 
 exit_free:
 	free(key);
 	free(value);
 	close(fd);
-	btf__free(btf);
 
 	return err;
 }
···
 	return 0;
 }
 
+static int do_pop_dequeue(int argc, char **argv)
+{
+	struct bpf_map_info info = {};
+	__u32 len = sizeof(info);
+	void *key, *value;
+	int err;
+	int fd;
+
+	if (argc < 2)
+		usage();
+
+	fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
+	if (fd < 0)
+		return -1;
+
+	err = alloc_key_value(&info, &key, &value);
+	if (err)
+		goto exit_free;
+
+	err = bpf_map_lookup_and_delete_elem(fd, key, value);
+	if (err) {
+		if (errno == ENOENT) {
+			if (json_output)
+				jsonw_null(json_wtr);
+			else
+				printf("Error: empty map\n");
+		} else {
+			p_err("pop failed: %s", strerror(errno));
+		}
+
+		goto exit_free;
+	}
+
+	print_key_value(&info, key, value);
+
+exit_free:
+	free(key);
+	free(value);
+	close(fd);
+
+	return err;
+}
+
 static int do_help(int argc, char **argv)
 {
 	if (json_output) {
···
 		"                              entries MAX_ENTRIES name NAME [flags FLAGS] \\\n"
 		"                              [dev NAME]\n"
 		"       %s %s dump       MAP\n"
-		"       %s %s update     MAP  key DATA value VALUE [UPDATE_FLAGS]\n"
-		"       %s %s lookup     MAP  key DATA\n"
+		"       %s %s update     MAP [key DATA] [value VALUE] [UPDATE_FLAGS]\n"
+		"       %s %s lookup     MAP [key DATA]\n"
 		"       %s %s getnext    MAP [key DATA]\n"
 		"       %s %s delete     MAP  key DATA\n"
 		"       %s %s pin        MAP  FILE\n"
 		"       %s %s event_pipe MAP [cpu N index M]\n"
+		"       %s %s peek       MAP\n"
+		"       %s %s push       MAP value VALUE\n"
+		"       %s %s pop        MAP\n"
+		"       %s %s enqueue    MAP value VALUE\n"
+		"       %s %s dequeue    MAP\n"
 		"       %s %s help\n"
 		"\n"
 		"       " HELP_SPEC_MAP "\n"
···
 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
-		bin_name, argv[-2]);
+		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
+		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2]);
 
 	return 0;
 }
···
 	{ "pin",	do_pin },
 	{ "event_pipe",	do_event_pipe },
 	{ "create",	do_create },
+	{ "peek",	do_lookup },
+	{ "push",	do_update },
+	{ "enqueue",	do_update },
+	{ "pop",	do_pop_dequeue },
+	{ "dequeue",	do_pop_dequeue },
 	{ 0 }
 };