1 files changed, 371 insertions, 73 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b699aea9a025..ac6eb863b2a4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
  * Copyright (C) 2015 Huawei Inc.
+ * Copyright (C) 2017 Nicira, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -22,15 +23,21 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include <libgen.h>
 #include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <asm/unistd.h>
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/bpf.h>
 #include <linux/list.h>
+#include <linux/limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
 #include <libelf.h>
 #include <gelf.h>
 
@@ -41,6 +48,10 @@
 #define EM_BPF 247
 #endif
 
+#ifndef BPF_FS_MAGIC
+#define BPF_FS_MAGIC		0xcafe4a11
+#endif
+
 #define __printf(a, b)	__attribute__((format(printf, a, b)))
 
 __printf(1, 2)
@@ -185,6 +196,7 @@ struct bpf_program {
 struct bpf_map {
 	int fd;
 	char *name;
+	size_t offset;
 	struct bpf_map_def def;
 	void *priv;
 	bpf_map_clear_priv_t clear_priv;
@@ -228,6 +240,10 @@ struct bpf_object {
 	 * all objects.
 	 */
 	struct list_head list;
+
+	void *priv;
+	bpf_object_clear_priv_t clear_priv;
+
 	char path[];
 };
 #define obj_elf_valid(o)	((o)->efile.elf)
@@ -513,57 +529,106 @@ bpf_object__init_kversion(struct bpf_object *obj,
 }
 
 static int
-bpf_object__init_maps(struct bpf_object *obj, void *data,
-		      size_t size)
+bpf_object__validate_maps(struct bpf_object *obj)
 {
-	size_t nr_maps;
 	int i;
 
-	nr_maps = size / sizeof(struct bpf_map_def);
-	if (!data || !nr_maps) {
-		pr_debug("%s doesn't need map definition\n",
-			 obj->path);
+	/*
+	 * If there's only 1 map, the only error case should have been
+	 * catched in bpf_object__init_maps().
+	 */
+	if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
 		return 0;
-	}
 
-	pr_debug("maps in %s: %zd bytes\n", obj->path, size);
+	for (i = 1; i < obj->nr_maps; i++) {
+		const struct bpf_map *a = &obj->maps[i - 1];
+		const struct bpf_map *b = &obj->maps[i];
 
-	obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
-	if (!obj->maps) {
-		pr_warning("alloc maps for object failed\n");
-		return -ENOMEM;
+		if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
+			pr_warning("corrupted map section in %s: map \"%s\" too small\n",
+				   obj->path, a->name);
+			return -EINVAL;
+		}
 	}
-	obj->nr_maps = nr_maps;
-
-	for (i = 0; i < nr_maps; i++) {
-		struct bpf_map_def *def = &obj->maps[i].def;
+	return 0;
+}
 
-		/*
-		 * fill all fd with -1 so won't close incorrect
-		 * fd (fd=0 is stdin) when failure (zclose won't close
-		 * negative fd)).
-		 */
-		obj->maps[i].fd = -1;
+static int compare_bpf_map(const void *_a, const void *_b)
+{
+	const struct bpf_map *a = _a;
+	const struct bpf_map *b = _b;
 
-		/* Save map definition into obj->maps */
-		*def = ((struct bpf_map_def *)data)[i];
-	}
-	return 0;
+	return a->offset - b->offset;
 }
 
 static int
-bpf_object__init_maps_name(struct bpf_object *obj)
+bpf_object__init_maps(struct bpf_object *obj)
 {
-	int i;
+	int i, map_idx, nr_maps = 0;
+	Elf_Scn *scn;
+	Elf_Data *data;
 	Elf_Data *symbols = obj->efile.symbols;
 
-	if (!symbols || obj->efile.maps_shndx < 0)
+	if (obj->efile.maps_shndx < 0)
+		return -EINVAL;
+	if (!symbols)
 		return -EINVAL;
 
+	scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
+	if (scn)
+		data = elf_getdata(scn, NULL);
+	if (!scn || !data) {
+		pr_warning("failed to get Elf_Data from map section %d\n",
+			   obj->efile.maps_shndx);
+		return -EINVAL;
+	}
+
+	/*
+	 * Count number of maps. Each map has a name.
+	 * Array of maps is not supported: only the first element is
+	 * considered.
+	 *
+	 * TODO: Detect array of map and report error.
+	 */
 	for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 		GElf_Sym sym;
-		size_t map_idx;
+
+		if (!gelf_getsym(symbols, i, &sym))
+			continue;
+		if (sym.st_shndx != obj->efile.maps_shndx)
+			continue;
+		nr_maps++;
+	}
+
+	/* Alloc obj->maps and fill nr_maps. */
+	pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
+		 nr_maps, data->d_size);
+
+	if (!nr_maps)
+		return 0;
+
+	obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
+	if (!obj->maps) {
+		pr_warning("alloc maps for object failed\n");
+		return -ENOMEM;
+	}
+	obj->nr_maps = nr_maps;
+
+	/*
+	 * fill all fd with -1 so won't close incorrect
+	 * fd (fd=0 is stdin) when failure (zclose won't close
+	 * negative fd)).
+	 */
+	for (i = 0; i < nr_maps; i++)
+		obj->maps[i].fd = -1;
+
+	/*
+	 * Fill obj->maps using data in "maps" section.
+	 */
+	for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
+		GElf_Sym sym;
 		const char *map_name;
+		struct bpf_map_def *def;
 
 		if (!gelf_getsym(symbols, i, &sym))
 			continue;
@@ -573,21 +638,27 @@ bpf_object__init_maps_name(struct bpf_object *obj)
 		map_name = elf_strptr(obj->efile.elf,
 				      obj->efile.strtabidx,
 				      sym.st_name);
-		map_idx = sym.st_value / sizeof(struct bpf_map_def);
-		if (map_idx >= obj->nr_maps) {
-			pr_warning("index of map \"%s\" is buggy: %zu > %zu\n",
-				   map_name, map_idx, obj->nr_maps);
-			continue;
+		obj->maps[map_idx].offset = sym.st_value;
+		if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
+			pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
+				   obj->path, map_name);
+			return -EINVAL;
 		}
+
 		obj->maps[map_idx].name = strdup(map_name);
 		if (!obj->maps[map_idx].name) {
 			pr_warning("failed to alloc map name\n");
 			return -ENOMEM;
 		}
-		pr_debug("map %zu is \"%s\"\n", map_idx,
+		pr_debug("map %d is \"%s\"\n", map_idx,
 			 obj->maps[map_idx].name);
+		def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
+		obj->maps[map_idx].def = *def;
+		map_idx++;
 	}
-	return 0;
+
+	qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
+	return bpf_object__validate_maps(obj);
 }
 
 static int bpf_object__elf_collect(struct bpf_object *obj)
@@ -645,11 +716,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
 			err = bpf_object__init_kversion(obj,
 							data->d_buf,
 							data->d_size);
-		else if (strcmp(name, "maps") == 0) {
-			err = bpf_object__init_maps(obj, data->d_buf,
-						    data->d_size);
+		else if (strcmp(name, "maps") == 0)
 			obj->efile.maps_shndx = idx;
-		} else if (sh.sh_type == SHT_SYMTAB) {
+		else if (sh.sh_type == SHT_SYMTAB) {
 			if (obj->efile.symbols) {
 				pr_warning("bpf: multiple SYMTAB in %s\n",
 					   obj->path);
@@ -698,7 +767,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
 		return LIBBPF_ERRNO__FORMAT;
 	}
 	if (obj->efile.maps_shndx >= 0)
-		err = bpf_object__init_maps_name(obj);
+		err = bpf_object__init_maps(obj);
 out:
 	return err;
 }
@@ -721,7 +790,7 @@ static int
 bpf_program__collect_reloc(struct bpf_program *prog,
 			   size_t nr_maps, GElf_Shdr *shdr,
 			   Elf_Data *data, Elf_Data *symbols,
-			   int maps_shndx)
+			   int maps_shndx, struct bpf_map *maps)
 {
 	int i, nrels;
 
@@ -771,7 +840,15 @@ bpf_program__collect_reloc(struct bpf_program *prog,
 			return -LIBBPF_ERRNO__RELOC;
 		}
 
-		map_idx = sym.st_value / sizeof(struct bpf_map_def);
+		/* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
+		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+			if (maps[map_idx].offset == sym.st_value) {
+				pr_debug("relocation: find map %zd (%s) for insn %u\n",
+					 map_idx, maps[map_idx].name, insn_idx);
+				break;
+			}
+		}
+
 		if (map_idx >= nr_maps) {
 			pr_warning("bpf relocation: map_idx %d large than %d\n",
 				   (int)map_idx, (int)nr_maps - 1);
@@ -796,7 +873,8 @@ bpf_object__create_maps(struct bpf_object *obj)
 		*pfd = bpf_create_map(def->type,
 				      def->key_size,
 				      def->value_size,
-				      def->max_entries);
+				      def->max_entries,
+				      0);
 		if (*pfd < 0) {
 			size_t j;
 			int err = *pfd;
@@ -807,7 +885,7 @@ bpf_object__create_maps(struct bpf_object *obj)
 				zclose(obj->maps[j].fd);
 			return err;
 		}
-		pr_debug("create map: fd=%d\n", *pfd);
+		pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
 	}
 
 	return 0;
@@ -894,7 +972,8 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
 		err = bpf_program__collect_reloc(prog, nr_maps,
 						 shdr, data,
 						 obj->efile.symbols,
-						 obj->efile.maps_shndx);
+						 obj->efile.maps_shndx,
+						 obj->maps);
 		if (err)
 			return err;
 	}
@@ -1168,6 +1247,191 @@ out:
 	return err;
 }
 
+static int check_path(const char *path)
+{
+	struct statfs st_fs;
+	char *dname, *dir;
+	int err = 0;
+
+	if (path == NULL)
+		return -EINVAL;
+
+	dname = strdup(path);
+	if (dname == NULL)
+		return -ENOMEM;
+
+	dir = dirname(dname);
+	if (statfs(dir, &st_fs)) {
+		pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
+		err = -errno;
+	}
+	free(dname);
+
+	if (!err && st_fs.f_type != BPF_FS_MAGIC) {
+		pr_warning("specified path %s is not on BPF FS\n", path);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
+			      int instance)
+{
+	int err;
+
+	err = check_path(path);
+	if (err)
+		return err;
+
+	if (prog == NULL) {
+		pr_warning("invalid program pointer\n");
+		return -EINVAL;
+	}
+
+	if (instance < 0 || instance >= prog->instances.nr) {
+		pr_warning("invalid prog instance %d of prog %s (max %d)\n",
+			   instance, prog->section_name, prog->instances.nr);
+		return -EINVAL;
+	}
+
+	if (bpf_obj_pin(prog->instances.fds[instance], path)) {
+		pr_warning("failed to pin program: %s\n", strerror(errno));
+		return -errno;
+	}
+	pr_debug("pinned program '%s'\n", path);
+
+	return 0;
+}
+
+static int make_dir(const char *path)
+{
+	int err = 0;
+
+	if (mkdir(path, 0700) && errno != EEXIST)
+		err = -errno;
+
+	if (err)
+		pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
+	return err;
+}
+
+int bpf_program__pin(struct bpf_program *prog, const char *path)
+{
+	int i, err;
+
+	err = check_path(path);
+	if (err)
+		return err;
+
+	if (prog == NULL) {
+		pr_warning("invalid program pointer\n");
+		return -EINVAL;
+	}
+
+	if (prog->instances.nr <= 0) {
+		pr_warning("no instances of prog %s to pin\n",
+			   prog->section_name);
+		return -EINVAL;
+	}
+
+	err = make_dir(path);
+	if (err)
+		return err;
+
+	for (i = 0; i < prog->instances.nr; i++) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
+		if (len < 0)
+			return -EINVAL;
+		else if (len >= PATH_MAX)
+			return -ENAMETOOLONG;
+
+		err = bpf_program__pin_instance(prog, buf, i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+int bpf_map__pin(struct bpf_map *map, const char *path)
+{
+	int err;
+
+	err = check_path(path);
+	if (err)
+		return err;
+
+	if (map == NULL) {
+		pr_warning("invalid map pointer\n");
+		return -EINVAL;
+	}
+
+	if (bpf_obj_pin(map->fd, path)) {
+		pr_warning("failed to pin map: %s\n", strerror(errno));
+		return -errno;
+	}
+
+	pr_debug("pinned map '%s'\n", path);
+	return 0;
+}
+
+int bpf_object__pin(struct bpf_object *obj, const char *path)
+{
+	struct bpf_program *prog;
+	struct bpf_map *map;
+	int err;
+
+	if (!obj)
+		return -ENOENT;
+
+	if (!obj->loaded) {
+		pr_warning("object not yet loaded; load it first\n");
+		return -ENOENT;
+	}
+
+	err = make_dir(path);
+	if (err)
+		return err;
+
+	bpf_map__for_each(map, obj) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%s", path,
+			       bpf_map__name(map));
+		if (len < 0)
+			return -EINVAL;
+		else if (len >= PATH_MAX)
+			return -ENAMETOOLONG;
+
+		err = bpf_map__pin(map, buf);
+		if (err)
+			return err;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%s", path,
+			       prog->section_name);
+		if (len < 0)
+			return -EINVAL;
+		else if (len >= PATH_MAX)
+			return -ENAMETOOLONG;
+
+		err = bpf_program__pin(prog, buf);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 void bpf_object__close(struct bpf_object *obj)
 {
 	size_t i;
@@ -1175,6 +1439,9 @@ void bpf_object__close(struct bpf_object *obj)
 	if (!obj)
 		return;
 
+	if (obj->clear_priv)
+		obj->clear_priv(obj, obj->priv);
+
 	bpf_object__elf_finish(obj);
 	bpf_object__unload(obj);
 
@@ -1228,6 +1495,22 @@ unsigned int bpf_object__kversion(struct bpf_object *obj)
 	return obj ? obj->kern_version : 0;
 }
 
+int bpf_object__set_priv(struct bpf_object *obj, void *priv,
+			 bpf_object_clear_priv_t clear_priv)
+{
+	if (obj->priv && obj->clear_priv)
+		obj->clear_priv(obj, obj->priv);
+
+	obj->priv = priv;
+	obj->clear_priv = clear_priv;
+	return 0;
+}
+
+void *bpf_object__priv(struct bpf_object *obj)
+{
+	return obj ? obj->priv : ERR_PTR(-EINVAL);
+}
+
 struct bpf_program *
 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
 {
@@ -1341,37 +1624,33 @@ static void bpf_program__set_type(struct bpf_program *prog,
 	prog->type = type;
 }
 
-int bpf_program__set_tracepoint(struct bpf_program *prog)
-{
-	if (!prog)
-		return -EINVAL;
-	bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT);
-	return 0;
-}
-
-int bpf_program__set_kprobe(struct bpf_program *prog)
-{
-	if (!prog)
-		return -EINVAL;
-	bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE);
-	return 0;
-}
-
 static bool bpf_program__is_type(struct bpf_program *prog,
 				 enum bpf_prog_type type)
 {
 	return prog ? (prog->type == type) : false;
 }
 
-bool bpf_program__is_tracepoint(struct bpf_program *prog)
-{
-	return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT);
-}
-
-bool bpf_program__is_kprobe(struct bpf_program *prog)
-{
-	return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE);
-}
+#define BPF_PROG_TYPE_FNS(NAME, TYPE)			\
+int bpf_program__set_##NAME(struct bpf_program *prog)	\
+{							\
+	if (!prog)					\
+		return -EINVAL;				\
+	bpf_program__set_type(prog, TYPE);		\
+	return 0;					\
+}							\
+							\
+bool bpf_program__is_##NAME(struct bpf_program *prog)	\
+{							\
+	return bpf_program__is_type(prog, TYPE);	\
+}							\
+
+BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
+BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
+BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
+BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
+BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
+BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
+BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
 
 int bpf_map__fd(struct bpf_map *map)
 {
@@ -1447,3 +1726,22 @@ bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
 	}
 	return NULL;
 }
+
+struct bpf_map *
+bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
+{
+	int i;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		if (obj->maps[i].offset == offset)
+			return &obj->maps[i];
+	}
+	return ERR_PTR(-ENOENT);
+}
+
+long libbpf_get_error(const void *ptr)
+{
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+	return 0;
+}