From 6446b3155521aab37f5a2b99ac264803ea7dced8 Mon Sep 17 00:00:00 2001
From: Hechao Li
Date: Mon, 10 Jun 2019 17:56:50 -0700
Subject: bpf: add a new API libbpf_num_possible_cpus()

Adding a new API libbpf_num_possible_cpus() that helps user with
per-CPU map operations.

Signed-off-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ba89d9727137..dd8b2cd5d3a7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3827,3 +3827,60 @@ void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
 					     desc->array_offset, addr);
 	}
 }
+
+int libbpf_num_possible_cpus(void)
+{
+	static const char *fcpu = "/sys/devices/system/cpu/possible";
+	int len = 0, n = 0, il = 0, ir = 0;
+	unsigned int start = 0, end = 0;
+	static int cpus;
+	char buf[128];
+	int error = 0;
+	int fd = -1;
+
+	if (cpus > 0)
+		return cpus;
+
+	fd = open(fcpu, O_RDONLY);
+	if (fd < 0) {
+		error = errno;
+		pr_warning("Failed to open file %s: %s\n",
+			   fcpu, strerror(error));
+		return -error;
+	}
+	len = read(fd, buf, sizeof(buf));
+	close(fd);
+	if (len <= 0) {
+		error = len ? errno : EINVAL;
+		pr_warning("Failed to read # of possible cpus from %s: %s\n",
+			   fcpu, strerror(error));
+		return -error;
+	}
+	if (len == sizeof(buf)) {
+		pr_warning("File %s size overflow\n", fcpu);
+		return -EOVERFLOW;
+	}
+	buf[len] = '\0';
+
+	for (ir = 0, cpus = 0; ir <= len; ir++) {
+		/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
+		if (buf[ir] == ',' || buf[ir] == '\0') {
+			buf[ir] = '\0';
+			n = sscanf(&buf[il], "%u-%u", &start, &end);
+			if (n <= 0) {
+				pr_warning("Failed to get # CPUs from %s\n",
+					   &buf[il]);
+				return -EINVAL;
+			} else if (n == 1) {
+				end = start;
+			}
+			cpus += end - start + 1;
+			il = ir + 1;
+		}
+	}
+	if (cpus <= 0) {
+		pr_warning("Invalid #CPUs %d from %s\n", cpus, fcpu);
+		return -EINVAL;
+	}
+	return cpus;
+}
-- 
cgit v1.2.3-55-g7522


From e55d54f43d3f11718d9e2800225097fda498e141 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Wed, 12 Jun 2019 22:04:57 -0700
Subject: libbpf: fix check for presence of associated BTF for map creation

Kernel internally checks that either key or value type ID is specified,
before using btf_fd. Do the same in libbpf's map creation code for
determining when to retry map creation w/o BTF.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: fba01a0689a9 ("libbpf: use negative fd to specify missing BTF")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index dd8b2cd5d3a7..e725fa86b189 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1736,7 +1736,7 @@ bpf_object__create_maps(struct bpf_object *obj)
 		create_attr.key_size = def->key_size;
 		create_attr.value_size = def->value_size;
 		create_attr.max_entries = def->max_entries;
-		create_attr.btf_fd = -1;
+		create_attr.btf_fd = 0;
 		create_attr.btf_key_type_id = 0;
 		create_attr.btf_value_type_id = 0;
 		if (bpf_map_type__is_map_in_map(def->type) &&
@@ -1750,11 +1750,12 @@ bpf_object__create_maps(struct bpf_object *obj)
 		}
 
 		*pfd = bpf_create_map_xattr(&create_attr);
-		if (*pfd < 0 && create_attr.btf_fd >= 0) {
+		if (*pfd < 0 && (create_attr.btf_key_type_id ||
+				 create_attr.btf_value_type_id)) {
 			cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
 			pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
 				   map->name, cp, errno);
-			create_attr.btf_fd = -1;
+			create_attr.btf_fd = 0;
 			create_attr.btf_key_type_id = 0;
 			create_attr.btf_value_type_id = 0;
 			map->btf_key_type_id = 0;
@@ -2045,7 +2046,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
 	load_attr.license = license;
 	load_attr.kern_version = kern_version;
 	load_attr.prog_ifindex = prog->prog_ifindex;
-	load_attr.prog_btf_fd = prog->btf_fd;
+	load_attr.prog_btf_fd = prog->btf_fd >= 0 ? prog->btf_fd : 0;
 	load_attr.func_info = prog->func_info;
 	load_attr.func_info_rec_size = prog->func_info_rec_size;
 	load_attr.func_info_cnt = prog->func_info_cnt;
-- 
cgit v1.2.3-55-g7522


From 9c6660d0406f8c32d21957ca9853108513bea8b1 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 12:26:51 -0700
Subject: libbpf: extract BTF loading logic

As a preparation for adding BTF-based BPF map loading, extract .BTF and
.BTF.ext loading logic.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 93 +++++++++++++++++++++++++++++---------------------
 1 file changed, 55 insertions(+), 38 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e725fa86b189..49d3a808e754 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1078,6 +1078,58 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
 	}
 }
 
+static int bpf_object__load_btf(struct bpf_object *obj,
+				Elf_Data *btf_data,
+				Elf_Data *btf_ext_data)
+{
+	int err = 0;
+
+	if (btf_data) {
+		obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
+		if (IS_ERR(obj->btf)) {
+			pr_warning("Error loading ELF section %s: %d.\n",
+				   BTF_ELF_SEC, err);
+			goto out;
+		}
+		err = btf__finalize_data(obj, obj->btf);
+		if (err) {
+			pr_warning("Error finalizing %s: %d.\n",
+				   BTF_ELF_SEC, err);
+			goto out;
+		}
+		bpf_object__sanitize_btf(obj);
+		err = btf__load(obj->btf);
+		if (err) {
+			pr_warning("Error loading %s into kernel: %d.\n",
+				   BTF_ELF_SEC, err);
+			goto out;
+		}
+	}
+	if (btf_ext_data) {
+		if (!obj->btf) {
+			pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
+				 BTF_EXT_ELF_SEC, BTF_ELF_SEC);
+			goto out;
+		}
+		obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
+					    btf_ext_data->d_size);
+		if (IS_ERR(obj->btf_ext)) {
+			pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
+				   BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
+			obj->btf_ext = NULL;
+			goto out;
+		}
+		bpf_object__sanitize_btf_ext(obj);
+	}
+out:
+	if (err || IS_ERR(obj->btf)) {
+		if (!IS_ERR_OR_NULL(obj->btf))
+			btf__free(obj->btf);
+		obj->btf = NULL;
+	}
+	return 0;
+}
+
 static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 {
 	Elf *elf = obj->efile.elf;
@@ -1212,44 +1264,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 		pr_warning("Corrupted ELF file: index of strtab invalid\n");
 		return -LIBBPF_ERRNO__FORMAT;
 	}
-	if (btf_data) {
-		obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
-		if (IS_ERR(obj->btf)) {
-			pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
-				   BTF_ELF_SEC, PTR_ERR(obj->btf));
-			obj->btf = NULL;
-		} else {
-			err = btf__finalize_data(obj, obj->btf);
-			if (!err) {
-				bpf_object__sanitize_btf(obj);
-				err = btf__load(obj->btf);
-			}
-			if (err) {
-				pr_warning("Error finalizing and loading %s into kernel: %d. Ignored and continue.\n",
-					   BTF_ELF_SEC, err);
-				btf__free(obj->btf);
-				obj->btf = NULL;
-				err = 0;
-			}
-		}
-	}
-	if (btf_ext_data) {
-		if (!obj->btf) {
-			pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
-				 BTF_EXT_ELF_SEC, BTF_ELF_SEC);
-		} else {
-			obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
-						    btf_ext_data->d_size);
-			if (IS_ERR(obj->btf_ext)) {
-				pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
-					   BTF_EXT_ELF_SEC,
-					   PTR_ERR(obj->btf_ext));
-				obj->btf_ext = NULL;
-			} else {
-				bpf_object__sanitize_btf_ext(obj);
-			}
-		}
-	}
+	err = bpf_object__load_btf(obj, btf_data, btf_ext_data);
+	if (err)
+		return err;
 	if (bpf_object__has_maps(obj)) {
 		err = bpf_object__init_maps(obj, flags);
 		if (err)
-- 
cgit v1.2.3-55-g7522


From 01b29d1dc9a06e2cdc6a0172d35605eb0300ecb2 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 12:26:52 -0700
Subject: libbpf: streamline ELF parsing error-handling

Simplify ELF parsing logic by exiting early, as there is no common clean
up path to execute. That makes it unnecessary to track when err was set
and when it was cleared. It also reduces nesting in some places.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 49d3a808e754..7ee44d8877c5 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1154,24 +1154,21 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 		if (gelf_getshdr(scn, &sh) != &sh) {
 			pr_warning("failed to get section(%d) header from %s\n",
 				   idx, obj->path);
-			err = -LIBBPF_ERRNO__FORMAT;
-			goto out;
+			return -LIBBPF_ERRNO__FORMAT;
 		}
 
 		name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 		if (!name) {
 			pr_warning("failed to get section(%d) name from %s\n",
 				   idx, obj->path);
-			err = -LIBBPF_ERRNO__FORMAT;
-			goto out;
+			return -LIBBPF_ERRNO__FORMAT;
 		}
 
 		data = elf_getdata(scn, 0);
 		if (!data) {
 			pr_warning("failed to get section(%d) data from %s(%s)\n",
 				   idx, name, obj->path);
-			err = -LIBBPF_ERRNO__FORMAT;
-			goto out;
+			return -LIBBPF_ERRNO__FORMAT;
 		}
 		pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
 			 idx, name, (unsigned long)data->d_size,
@@ -1182,10 +1179,14 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 			err = bpf_object__init_license(obj,
 						       data->d_buf,
 						       data->d_size);
+			if (err)
+				return err;
 		} else if (strcmp(name, "version") == 0) {
 			err = bpf_object__init_kversion(obj,
 							data->d_buf,
 							data->d_size);
+			if (err)
+				return err;
 		} else if (strcmp(name, "maps") == 0) {
 			obj->efile.maps_shndx = idx;
 		} else if (strcmp(name, BTF_ELF_SEC) == 0) {
@@ -1196,11 +1197,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 			if (obj->efile.symbols) {
 				pr_warning("bpf: multiple SYMTAB in %s\n",
 					   obj->path);
-				err = -LIBBPF_ERRNO__FORMAT;
-			} else {
-				obj->efile.symbols = data;
-				obj->efile.strtabidx = sh.sh_link;
+				return -LIBBPF_ERRNO__FORMAT;
 			}
+			obj->efile.symbols = data;
+			obj->efile.strtabidx = sh.sh_link;
 		} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
 			if (sh.sh_flags & SHF_EXECINSTR) {
 				if (strcmp(name, ".text") == 0)
@@ -1214,6 +1214,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 
 					pr_warning("failed to alloc program %s (%s): %s",
 						   name, obj->path, cp);
+					return err;
 				}
 			} else if (strcmp(name, ".data") == 0) {
 				obj->efile.data = data;
@@ -1225,8 +1226,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 				pr_debug("skip section(%d) %s\n", idx, name);
 			}
 		} else if (sh.sh_type == SHT_REL) {
+			int nr_reloc = obj->efile.nr_reloc;
 			void *reloc = obj->efile.reloc;
-			int nr_reloc = obj->efile.nr_reloc + 1;
 			int sec = sh.sh_info; /* points to other section */
 
 			/* Only do relo for section with exec instructions */
@@ -1236,28 +1237,24 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 				continue;
 			}
 
-			reloc = reallocarray(reloc, nr_reloc,
+			reloc = reallocarray(reloc, nr_reloc + 1,
 					     sizeof(*obj->efile.reloc));
 			if (!reloc) {
 				pr_warning("realloc failed\n");
-				err = -ENOMEM;
-			} else {
-				int n = nr_reloc - 1;
+				return -ENOMEM;
+			}
 
-				obj->efile.reloc = reloc;
-				obj->efile.nr_reloc = nr_reloc;
+			obj->efile.reloc = reloc;
+			obj->efile.nr_reloc++;
 
-				obj->efile.reloc[n].shdr = sh;
-				obj->efile.reloc[n].data = data;
-			}
+			obj->efile.reloc[nr_reloc].shdr = sh;
+			obj->efile.reloc[nr_reloc].data = data;
 		} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
 			obj->efile.bss = data;
 			obj->efile.bss_shndx = idx;
 		} else {
 			pr_debug("skip section(%d) %s\n", idx, name);
 		}
-		if (err)
-			goto out;
 	}
 
 	if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
@@ -1270,10 +1267,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 	if (bpf_object__has_maps(obj)) {
 		err = bpf_object__init_maps(obj, flags);
 		if (err)
-			goto out;
+			return err;
 	}
 	err = bpf_object__init_prog_names(obj);
-out:
 	return err;
 }
 
-- 
cgit v1.2.3-55-g7522


From bf82927125dd25003d76ed5541da704df21de57a Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 12:26:53 -0700
Subject: libbpf: refactor map initialization

User and global data maps initialization has gotten pretty complicated
and unnecessarily convoluted. This patch splits out the logic for global
data map and user-defined map initialization. It also removes the
restriction of pre-calculating how many maps will be initialized,
instead allowing to keep adding new maps as they are discovered, which
will be used later for BTF-defined map definitions.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 247 ++++++++++++++++++++++++++-----------------------
 1 file changed, 133 insertions(+), 114 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 7ee44d8877c5..88609dca4f7d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -234,6 +234,7 @@ struct bpf_object {
 	size_t nr_programs;
 	struct bpf_map *maps;
 	size_t nr_maps;
+	size_t maps_cap;
 	struct bpf_secdata sections;
 
 	bool loaded;
@@ -763,21 +764,51 @@ int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
 	return -ENOENT;
 }
 
-static bool bpf_object__has_maps(const struct bpf_object *obj)
+static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
 {
-	return obj->efile.maps_shndx >= 0 ||
-	       obj->efile.data_shndx >= 0 ||
-	       obj->efile.rodata_shndx >= 0 ||
-	       obj->efile.bss_shndx >= 0;
+	struct bpf_map *new_maps;
+	size_t new_cap;
+	int i;
+
+	if (obj->nr_maps < obj->maps_cap)
+		return &obj->maps[obj->nr_maps++];
+
+	new_cap = max(4ul, obj->maps_cap * 3 / 2);
+	new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
+	if (!new_maps) {
+		pr_warning("alloc maps for object failed\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	obj->maps_cap = new_cap;
+	obj->maps = new_maps;
+
+	/* zero out new maps */
+	memset(obj->maps + obj->nr_maps, 0,
+	       (obj->maps_cap - obj->nr_maps) * sizeof(*obj->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 = obj->nr_maps; i < obj->maps_cap; i++) {
+		obj->maps[i].fd = -1;
+		obj->maps[i].inner_map_fd = -1;
+	}
+
+	return &obj->maps[obj->nr_maps++];
 }
 
 static int
-bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map,
-			      enum libbpf_map_type type, Elf_Data *data,
-			      void **data_buff)
+bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
+			      Elf_Data *data, void **data_buff)
 {
-	struct bpf_map_def *def = &map->def;
 	char map_name[BPF_OBJ_NAME_LEN];
+	struct bpf_map_def *def;
+	struct bpf_map *map;
+
+	map = bpf_object__add_map(obj);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
 
 	map->libbpf_type = type;
 	map->offset = ~(typeof(map->offset))0;
@@ -789,6 +820,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map,
 		return -ENOMEM;
 	}
 
+	def = &map->def;
 	def->type = BPF_MAP_TYPE_ARRAY;
 	def->key_size = sizeof(int);
 	def->value_size = data->d_size;
@@ -808,29 +840,58 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map,
 	return 0;
 }
 
-static int bpf_object__init_maps(struct bpf_object *obj, int flags)
+static int bpf_object__init_global_data_maps(struct bpf_object *obj)
+{
+	int err;
+
+	if (!obj->caps.global_data)
+		return 0;
+	/*
+	 * Populate obj->maps with libbpf internal maps.
+	 */
+	if (obj->efile.data_shndx >= 0) {
+		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
+						    obj->efile.data,
+						    &obj->sections.data);
+		if (err)
+			return err;
+	}
+	if (obj->efile.rodata_shndx >= 0) {
+		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
+						    obj->efile.rodata,
+						    &obj->sections.rodata);
+		if (err)
+			return err;
+	}
+	if (obj->efile.bss_shndx >= 0) {
+		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
+						    obj->efile.bss, NULL);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 {
-	int i, map_idx, map_def_sz = 0, nr_syms, nr_maps = 0, nr_maps_glob = 0;
-	bool strict = !(flags & MAPS_RELAX_COMPAT);
 	Elf_Data *symbols = obj->efile.symbols;
+	int i, map_def_sz = 0, nr_maps = 0, nr_syms;
 	Elf_Data *data = NULL;
-	int ret = 0;
+	Elf_Scn *scn;
+
+	if (obj->efile.maps_shndx < 0)
+		return 0;
 
 	if (!symbols)
 		return -EINVAL;
-	nr_syms = symbols->d_size / sizeof(GElf_Sym);
-
-	if (obj->efile.maps_shndx >= 0) {
-		Elf_Scn *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;
-		}
+	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;
 	}
 
 	/*
@@ -840,16 +901,8 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
 	 *
 	 * TODO: Detect array of map and report error.
 	 */
-	if (obj->caps.global_data) {
-		if (obj->efile.data_shndx >= 0)
-			nr_maps_glob++;
-		if (obj->efile.rodata_shndx >= 0)
-			nr_maps_glob++;
-		if (obj->efile.bss_shndx >= 0)
-			nr_maps_glob++;
-	}
-
-	for (i = 0; data && i < nr_syms; i++) {
+	nr_syms = symbols->d_size / sizeof(GElf_Sym);
+	for (i = 0; i < nr_syms; i++) {
 		GElf_Sym sym;
 
 		if (!gelf_getsym(symbols, i, &sym))
@@ -858,79 +911,56 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
 			continue;
 		nr_maps++;
 	}
-
-	if (!nr_maps && !nr_maps_glob)
-		return 0;
-
 	/* Assume equally sized map definitions */
-	if (data) {
-		pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
-			 nr_maps, data->d_size);
-
-		map_def_sz = data->d_size / nr_maps;
-		if (!data->d_size || (data->d_size % nr_maps) != 0) {
-			pr_warning("unable to determine map definition size "
-				   "section %s, %d maps in %zd bytes\n",
-				   obj->path, nr_maps, data->d_size);
-			return -EINVAL;
-		}
-	}
-
-	nr_maps += nr_maps_glob;
-	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;
-
-	for (i = 0; i < nr_maps; i++) {
-		/*
-		 * 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;
-		obj->maps[i].inner_map_fd = -1;
+	pr_debug("maps in %s: %d maps in %zd bytes\n",
+		 obj->path, nr_maps, data->d_size);
+
+	map_def_sz = data->d_size / nr_maps;
+	if (!data->d_size || (data->d_size % nr_maps) != 0) {
+		pr_warning("unable to determine map definition size "
+			   "section %s, %d maps in %zd bytes\n",
+			   obj->path, nr_maps, data->d_size);
+		return -EINVAL;
 	}
 
-	/*
-	 * Fill obj->maps using data in "maps" section.
-	 */
-	for (i = 0, map_idx = 0; data && i < nr_syms; i++) {
+	/* Fill obj->maps using data in "maps" section.  */
+	for (i = 0; i < nr_syms; i++) {
 		GElf_Sym sym;
 		const char *map_name;
 		struct bpf_map_def *def;
+		struct bpf_map *map;
 
 		if (!gelf_getsym(symbols, i, &sym))
 			continue;
 		if (sym.st_shndx != obj->efile.maps_shndx)
 			continue;
 
-		map_name = elf_strptr(obj->efile.elf,
-				      obj->efile.strtabidx,
+		map = bpf_object__add_map(obj);
+		if (IS_ERR(map))
+			return PTR_ERR(map);
+
+		map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
 				      sym.st_name);
 		if (!map_name) {
 			pr_warning("failed to get map #%d name sym string for obj %s\n",
-				   map_idx, obj->path);
+				   i, obj->path);
 			return -LIBBPF_ERRNO__FORMAT;
 		}
 
-		obj->maps[map_idx].libbpf_type = LIBBPF_MAP_UNSPEC;
-		obj->maps[map_idx].offset = sym.st_value;
+		map->libbpf_type = LIBBPF_MAP_UNSPEC;
+		map->offset = sym.st_value;
 		if (sym.st_value + map_def_sz > 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) {
+		map->name = strdup(map_name);
+		if (!map->name) {
 			pr_warning("failed to alloc map name\n");
 			return -ENOMEM;
 		}
-		pr_debug("map %d is \"%s\"\n", map_idx,
-			 obj->maps[map_idx].name);
+		pr_debug("map %d is \"%s\"\n", i, map->name);
 		def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
 		/*
 		 * If the definition of the map in the object file fits in
@@ -939,7 +969,7 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
 		 * calloc above.
 		 */
 		if (map_def_sz <= sizeof(struct bpf_map_def)) {
-			memcpy(&obj->maps[map_idx].def, def, map_def_sz);
+			memcpy(&map->def, def, map_def_sz);
 		} else {
 			/*
 			 * Here the map structure being read is bigger than what
@@ -959,37 +989,30 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
 						return -EINVAL;
 				}
 			}
-			memcpy(&obj->maps[map_idx].def, def,
-			       sizeof(struct bpf_map_def));
+			memcpy(&map->def, def, sizeof(struct bpf_map_def));
 		}
-		map_idx++;
 	}
+	return 0;
+}
 
-	if (!obj->caps.global_data)
-		goto finalize;
+static int bpf_object__init_maps(struct bpf_object *obj, int flags)
+{
+	bool strict = !(flags & MAPS_RELAX_COMPAT);
+	int err;
 
-	/*
-	 * Populate rest of obj->maps with libbpf internal maps.
-	 */
-	if (obj->efile.data_shndx >= 0)
-		ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
-						    LIBBPF_MAP_DATA,
-						    obj->efile.data,
-						    &obj->sections.data);
-	if (!ret && obj->efile.rodata_shndx >= 0)
-		ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
-						    LIBBPF_MAP_RODATA,
-						    obj->efile.rodata,
-						    &obj->sections.rodata);
-	if (!ret && obj->efile.bss_shndx >= 0)
-		ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
-						    LIBBPF_MAP_BSS,
-						    obj->efile.bss, NULL);
-finalize:
-	if (!ret)
+	err = bpf_object__init_user_maps(obj, strict);
+	if (err)
+		return err;
+
+	err = bpf_object__init_global_data_maps(obj);
+	if (err)
+		return err;
+
+	if (obj->nr_maps) {
 		qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
 		      compare_bpf_map);
-	return ret;
+	}
+	return 0;
 }
 
 static bool section_have_execinstr(struct bpf_object *obj, int idx)
@@ -1262,14 +1285,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 		return -LIBBPF_ERRNO__FORMAT;
 	}
 	err = bpf_object__load_btf(obj, btf_data, btf_ext_data);
-	if (err)
-		return err;
-	if (bpf_object__has_maps(obj)) {
+	if (!err)
 		err = bpf_object__init_maps(obj, flags);
-		if (err)
-			return err;
-	}
-	err = bpf_object__init_prog_names(obj);
+	if (!err)
+		err = bpf_object__init_prog_names(obj);
 	return err;
 }
 
-- 
cgit v1.2.3-55-g7522


From db48814bd2833ee231f48bd2030082369b88f9ef Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 12:26:54 -0700
Subject: libbpf: identify maps by section index in addition to offset

To support maps to be defined in multiple sections, it's important to
identify map not just by offset within its section, but section index as
well. This patch adds tracking of section index.

For global data, we record section index of corresponding
.data/.bss/.rodata ELF section for uniformity, and thus don't need
a special value of offset for those maps.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 88609dca4f7d..b1f3ab4b39b3 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -207,7 +207,8 @@ static const char * const libbpf_type_to_btf_name[] = {
 struct bpf_map {
 	int fd;
 	char *name;
-	size_t offset;
+	int sec_idx;
+	size_t sec_offset;
 	int map_ifindex;
 	int inner_map_fd;
 	struct bpf_map_def def;
@@ -647,7 +648,9 @@ static int compare_bpf_map(const void *_a, const void *_b)
 	const struct bpf_map *a = _a;
 	const struct bpf_map *b = _b;
 
-	return a->offset - b->offset;
+	if (a->sec_idx != b->sec_idx)
+		return a->sec_idx - b->sec_idx;
+	return a->sec_offset - b->sec_offset;
 }
 
 static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
@@ -800,7 +803,7 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
 
 static int
 bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
-			      Elf_Data *data, void **data_buff)
+			      int sec_idx, Elf_Data *data, void **data_buff)
 {
 	char map_name[BPF_OBJ_NAME_LEN];
 	struct bpf_map_def *def;
@@ -811,7 +814,8 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
 		return PTR_ERR(map);
 
 	map->libbpf_type = type;
-	map->offset = ~(typeof(map->offset))0;
+	map->sec_idx = sec_idx;
+	map->sec_offset = 0;
 	snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
 		 libbpf_type_to_btf_name[type]);
 	map->name = strdup(map_name);
@@ -819,6 +823,8 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
 		pr_warning("failed to alloc map name\n");
 		return -ENOMEM;
 	}
+	pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n",
+		 map_name, map->sec_idx, map->sec_offset);
 
 	def = &map->def;
 	def->type = BPF_MAP_TYPE_ARRAY;
@@ -851,6 +857,7 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj)
 	 */
 	if (obj->efile.data_shndx >= 0) {
 		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
+						    obj->efile.data_shndx,
 						    obj->efile.data,
 						    &obj->sections.data);
 		if (err)
@@ -858,6 +865,7 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj)
 	}
 	if (obj->efile.rodata_shndx >= 0) {
 		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
+						    obj->efile.rodata_shndx,
 						    obj->efile.rodata,
 						    &obj->sections.rodata);
 		if (err)
@@ -865,6 +873,7 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj)
 	}
 	if (obj->efile.bss_shndx >= 0) {
 		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
+						    obj->efile.bss_shndx,
 						    obj->efile.bss, NULL);
 		if (err)
 			return err;
@@ -948,7 +957,10 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 		}
 
 		map->libbpf_type = LIBBPF_MAP_UNSPEC;
-		map->offset = sym.st_value;
+		map->sec_idx = sym.st_shndx;
+		map->sec_offset = sym.st_value;
+		pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
+			 map_name, map->sec_idx, map->sec_offset);
 		if (sym.st_value + map_def_sz > data->d_size) {
 			pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
 				   obj->path, map_name);
@@ -1448,9 +1460,13 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 				if (maps[map_idx].libbpf_type != type)
 					continue;
 				if (type != LIBBPF_MAP_UNSPEC ||
-				    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);
+				    (maps[map_idx].sec_idx == sym.st_shndx &&
+				     maps[map_idx].sec_offset == sym.st_value)) {
+					pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n",
+						 map_idx, maps[map_idx].name,
+						 maps[map_idx].sec_idx,
+						 maps[map_idx].sec_offset,
+						 insn_idx);
 					break;
 				}
 			}
@@ -3468,13 +3484,7 @@ bpf_object__find_map_fd_by_name(struct bpf_object *obj, const char *name)
 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);
+	return ERR_PTR(-ENOTSUP);
 }
 
 long libbpf_get_error(const void *ptr)
-- 
cgit v1.2.3-55-g7522


From 063183bf0486c7e61a2b454896bba2f7908b4ab0 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 12:26:55 -0700
Subject: libbpf: split initialization and loading of BTF

Libbpf does sanitization of BTF before loading it into kernel, if kernel
doesn't support some of newer BTF features. This removes some of the
important information from BTF (e.g., DATASEC and VAR description),
which will be used for map construction. This patch splits BTF
processing into initialization step, in which BTF is initialized from
ELF and all the original data is still preserved; and
sanitization/loading step, which ensures that BTF is safe to load into
kernel. This allows to use full BTF information to construct maps, while
still loading valid BTF into older kernels.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b1f3ab4b39b3..da942ab2f06a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1113,7 +1113,7 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
 	}
 }
 
-static int bpf_object__load_btf(struct bpf_object *obj,
+static int bpf_object__init_btf(struct bpf_object *obj,
 				Elf_Data *btf_data,
 				Elf_Data *btf_ext_data)
 {
@@ -1132,13 +1132,6 @@ static int bpf_object__load_btf(struct bpf_object *obj,
 				   BTF_ELF_SEC, err);
 			goto out;
 		}
-		bpf_object__sanitize_btf(obj);
-		err = btf__load(obj->btf);
-		if (err) {
-			pr_warning("Error loading %s into kernel: %d.\n",
-				   BTF_ELF_SEC, err);
-			goto out;
-		}
 	}
 	if (btf_ext_data) {
 		if (!obj->btf) {
@@ -1154,7 +1147,6 @@ static int bpf_object__load_btf(struct bpf_object *obj,
 			obj->btf_ext = NULL;
 			goto out;
 		}
-		bpf_object__sanitize_btf_ext(obj);
 	}
 out:
 	if (err || IS_ERR(obj->btf)) {
@@ -1165,6 +1157,26 @@ out:
 	return 0;
 }
 
+static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
+{
+	int err = 0;
+
+	if (!obj->btf)
+		return 0;
+
+	bpf_object__sanitize_btf(obj);
+	bpf_object__sanitize_btf_ext(obj);
+
+	err = btf__load(obj->btf);
+	if (err) {
+		pr_warning("Error loading %s into kernel: %d.\n",
+			   BTF_ELF_SEC, err);
+		btf__free(obj->btf);
+		obj->btf = NULL;
+	}
+	return 0;
+}
+
 static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 {
 	Elf *elf = obj->efile.elf;
@@ -1296,9 +1308,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 		pr_warning("Corrupted ELF file: index of strtab invalid\n");
 		return -LIBBPF_ERRNO__FORMAT;
 	}
-	err = bpf_object__load_btf(obj, btf_data, btf_ext_data);
+	err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
 	if (!err)
 		err = bpf_object__init_maps(obj, flags);
+	if (!err)
+		err = bpf_object__sanitize_and_load_btf(obj);
 	if (!err)
 		err = bpf_object__init_prog_names(obj);
 	return err;
-- 
cgit v1.2.3-55-g7522


From abd29c9314595b1ee5ec6c61d7c49a497ffb30a3 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 12:26:56 -0700
Subject: libbpf: allow specifying map definitions using BTF

This patch adds support for a new way to define BPF maps. It relies on
BTF to describe mandatory and optional attributes of a map, as well as
captures type information of key and value naturally. This eliminates
the need for BPF_ANNOTATE_KV_PAIR hack and ensures key/value sizes are
always in sync with the key/value type.

Relying on BTF, this approach allows for both forward and backward
compatibility w.r.t. extending supported map definition features. By
default, any unrecognized attributes are treated as an error, but it's
possible relax this using MAPS_RELAX_COMPAT flag. New attributes, added
in the future will need to be optional.

The outline of the new map definition (short, BTF-defined maps) is as follows:
1. All the maps should be defined in .maps ELF section. It's possible to
   have both "legacy" map definitions in `maps` sections and BTF-defined
   maps in .maps sections. Everything will still work transparently.
2. The map declaration and initialization is done through
   a global/static variable of a struct type with few mandatory and
   extra optional fields:
   - type field is mandatory and specified type of BPF map;
   - key/value fields are mandatory and capture key/value type/size information;
   - max_entries attribute is optional; if max_entries is not specified or
     initialized, it has to be provided in runtime through libbpf API
     before loading bpf_object;
   - map_flags is optional and if not defined, will be assumed to be 0.
3. Key/value fields should be **a pointer** to a type describing
   key/value. The pointee type is assumed (and will be recorded as such
   and used for size determination) to be a type describing key/value of
   the map. This is done to save excessive amounts of space allocated in
   corresponding ELF sections for key/value of big size.
4. As some maps disallow having BTF type ID associated with key/value,
   it's possible to specify key/value size explicitly without
   associating BTF type ID with it. Use key_size and value_size fields
   to do that (see example below).

Here's an example of simple ARRAY map defintion:

struct my_value { int x, y, z; };

struct {
	int type;
	int max_entries;
	int *key;
	struct my_value *value;
} btf_map SEC(".maps") = {
	.type = BPF_MAP_TYPE_ARRAY,
	.max_entries = 16,
};

This will define BPF ARRAY map 'btf_map' with 16 elements. The key will
be of type int and thus key size will be 4 bytes. The value is struct
my_value of size 12 bytes. This map can be used from C code exactly the
same as with existing maps defined through struct bpf_map_def.

Here's an example of STACKMAP definition (which currently disallows BTF type
IDs for key/value):

struct {
	__u32 type;
	__u32 max_entries;
	__u32 map_flags;
	__u32 key_size;
	__u32 value_size;
} stackmap SEC(".maps") = {
	.type = BPF_MAP_TYPE_STACK_TRACE,
	.max_entries = 128,
	.map_flags = BPF_F_STACK_BUILD_ID,
	.key_size = sizeof(__u32),
	.value_size = PERF_MAX_STACK_DEPTH * sizeof(struct bpf_stack_build_id),
};

This approach is naturally extended to support map-in-map, by making a value
field to be another struct that describes inner map. This feature is not
implemented yet. It's also possible to incrementally add features like pinning
with full backwards and forward compatibility. Support for static
initialization of BPF_MAP_TYPE_PROG_ARRAY using pointers to BPF programs
is also on the roadmap.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/btf.h    |   1 +
 tools/lib/bpf/libbpf.c | 353 +++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 345 insertions(+), 9 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index ba4ffa831aa4..88a52ae56fc6 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -17,6 +17,7 @@ extern "C" {
 
 #define BTF_ELF_SEC ".BTF"
 #define BTF_EXT_ELF_SEC ".BTF.ext"
+#define MAPS_ELF_SEC ".maps"
 
 struct btf;
 struct btf_ext;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index da942ab2f06a..585e3a2f1eb4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -262,6 +262,7 @@ struct bpf_object {
 		} *reloc;
 		int nr_reloc;
 		int maps_shndx;
+		int btf_maps_shndx;
 		int text_shndx;
 		int data_shndx;
 		int rodata_shndx;
@@ -514,6 +515,7 @@ static struct bpf_object *bpf_object__new(const char *path,
 	obj->efile.obj_buf = obj_buf;
 	obj->efile.obj_buf_sz = obj_buf_sz;
 	obj->efile.maps_shndx = -1;
+	obj->efile.btf_maps_shndx = -1;
 	obj->efile.data_shndx = -1;
 	obj->efile.rodata_shndx = -1;
 	obj->efile.bss_shndx = -1;
@@ -1007,6 +1009,312 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 	return 0;
 }
 
+static const struct btf_type *skip_mods_and_typedefs(const struct btf *btf,
+						     __u32 id)
+{
+	const struct btf_type *t = btf__type_by_id(btf, id);
+
+	while (true) {
+		switch (BTF_INFO_KIND(t->info)) {
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_TYPEDEF:
+			t = btf__type_by_id(btf, t->type);
+			break;
+		default:
+			return t;
+		}
+	}
+}
+
+static bool get_map_field_int(const char *map_name,
+			      const struct btf *btf,
+			      const struct btf_type *def,
+			      const struct btf_member *m,
+			      const void *data, __u32 *res) {
+	const struct btf_type *t = skip_mods_and_typedefs(btf, m->type);
+	const char *name = btf__name_by_offset(btf, m->name_off);
+	__u32 int_info = *(const __u32 *)(const void *)(t + 1);
+
+	if (BTF_INFO_KIND(t->info) != BTF_KIND_INT) {
+		pr_warning("map '%s': attr '%s': expected INT, got %u.\n",
+			   map_name, name, BTF_INFO_KIND(t->info));
+		return false;
+	}
+	if (t->size != 4 || BTF_INT_BITS(int_info) != 32 ||
+	    BTF_INT_OFFSET(int_info)) {
+		pr_warning("map '%s': attr '%s': expected 32-bit non-bitfield integer, "
+			   "got %u-byte (%d-bit) one with bit offset %d.\n",
+			   map_name, name, t->size, BTF_INT_BITS(int_info),
+			   BTF_INT_OFFSET(int_info));
+		return false;
+	}
+	if (BTF_INFO_KFLAG(def->info) && BTF_MEMBER_BITFIELD_SIZE(m->offset)) {
+		pr_warning("map '%s': attr '%s': bitfield is not supported.\n",
+			   map_name, name);
+		return false;
+	}
+	if (m->offset % 32) {
+		pr_warning("map '%s': attr '%s': unaligned fields are not supported.\n",
+			   map_name, name);
+		return false;
+	}
+
+	*res = *(const __u32 *)(data + m->offset / 8);
+	return true;
+}
+
+static int bpf_object__init_user_btf_map(struct bpf_object *obj,
+					 const struct btf_type *sec,
+					 int var_idx, int sec_idx,
+					 const Elf_Data *data, bool strict)
+{
+	const struct btf_type *var, *def, *t;
+	const struct btf_var_secinfo *vi;
+	const struct btf_var *var_extra;
+	const struct btf_member *m;
+	const void *def_data;
+	const char *map_name;
+	struct bpf_map *map;
+	int vlen, i;
+
+	vi = (const struct btf_var_secinfo *)(const void *)(sec + 1) + var_idx;
+	var = btf__type_by_id(obj->btf, vi->type);
+	var_extra = (const void *)(var + 1);
+	map_name = btf__name_by_offset(obj->btf, var->name_off);
+	vlen = BTF_INFO_VLEN(var->info);
+
+	if (map_name == NULL || map_name[0] == '\0') {
+		pr_warning("map #%d: empty name.\n", var_idx);
+		return -EINVAL;
+	}
+	if ((__u64)vi->offset + vi->size > data->d_size) {
+		pr_warning("map '%s' BTF data is corrupted.\n", map_name);
+		return -EINVAL;
+	}
+	if (BTF_INFO_KIND(var->info) != BTF_KIND_VAR) {
+		pr_warning("map '%s': unexpected var kind %u.\n",
+			   map_name, BTF_INFO_KIND(var->info));
+		return -EINVAL;
+	}
+	if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
+	    var_extra->linkage != BTF_VAR_STATIC) {
+		pr_warning("map '%s': unsupported var linkage %u.\n",
+			   map_name, var_extra->linkage);
+		return -EOPNOTSUPP;
+	}
+
+	def = skip_mods_and_typedefs(obj->btf, var->type);
+	if (BTF_INFO_KIND(def->info) != BTF_KIND_STRUCT) {
+		pr_warning("map '%s': unexpected def kind %u.\n",
+			   map_name, BTF_INFO_KIND(var->info));
+		return -EINVAL;
+	}
+	if (def->size > vi->size) {
+		pr_warning("map '%s': invalid def size.\n", map_name);
+		return -EINVAL;
+	}
+
+	map = bpf_object__add_map(obj);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	map->name = strdup(map_name);
+	if (!map->name) {
+		pr_warning("map '%s': failed to alloc map name.\n", map_name);
+		return -ENOMEM;
+	}
+	map->libbpf_type = LIBBPF_MAP_UNSPEC;
+	map->def.type = BPF_MAP_TYPE_UNSPEC;
+	map->sec_idx = sec_idx;
+	map->sec_offset = vi->offset;
+	pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
+		 map_name, map->sec_idx, map->sec_offset);
+
+	def_data = data->d_buf + vi->offset;
+	vlen = BTF_INFO_VLEN(def->info);
+	m = (const void *)(def + 1);
+	for (i = 0; i < vlen; i++, m++) {
+		const char *name = btf__name_by_offset(obj->btf, m->name_off);
+
+		if (!name) {
+			pr_warning("map '%s': invalid field #%d.\n",
+				   map_name, i);
+			return -EINVAL;
+		}
+		if (strcmp(name, "type") == 0) {
+			if (!get_map_field_int(map_name, obj->btf, def, m,
+					       def_data, &map->def.type))
+				return -EINVAL;
+			pr_debug("map '%s': found type = %u.\n",
+				 map_name, map->def.type);
+		} else if (strcmp(name, "max_entries") == 0) {
+			if (!get_map_field_int(map_name, obj->btf, def, m,
+					       def_data, &map->def.max_entries))
+				return -EINVAL;
+			pr_debug("map '%s': found max_entries = %u.\n",
+				 map_name, map->def.max_entries);
+		} else if (strcmp(name, "map_flags") == 0) {
+			if (!get_map_field_int(map_name, obj->btf, def, m,
+					       def_data, &map->def.map_flags))
+				return -EINVAL;
+			pr_debug("map '%s': found map_flags = %u.\n",
+				 map_name, map->def.map_flags);
+		} else if (strcmp(name, "key_size") == 0) {
+			__u32 sz;
+
+			if (!get_map_field_int(map_name, obj->btf, def, m,
+					       def_data, &sz))
+				return -EINVAL;
+			pr_debug("map '%s': found key_size = %u.\n",
+				 map_name, sz);
+			if (map->def.key_size && map->def.key_size != sz) {
+				pr_warning("map '%s': conflictling key size %u != %u.\n",
+					   map_name, map->def.key_size, sz);
+				return -EINVAL;
+			}
+			map->def.key_size = sz;
+		} else if (strcmp(name, "key") == 0) {
+			__s64 sz;
+
+			t = btf__type_by_id(obj->btf, m->type);
+			if (!t) {
+				pr_warning("map '%s': key type [%d] not found.\n",
+					   map_name, m->type);
+				return -EINVAL;
+			}
+			if (BTF_INFO_KIND(t->info) != BTF_KIND_PTR) {
+				pr_warning("map '%s': key spec is not PTR: %u.\n",
+					   map_name, BTF_INFO_KIND(t->info));
+				return -EINVAL;
+			}
+			sz = btf__resolve_size(obj->btf, t->type);
+			if (sz < 0) {
+				pr_warning("map '%s': can't determine key size for type [%u]: %lld.\n",
+					   map_name, t->type, sz);
+				return sz;
+			}
+			pr_debug("map '%s': found key [%u], sz = %lld.\n",
+				 map_name, t->type, sz);
+			if (map->def.key_size && map->def.key_size != sz) {
+				pr_warning("map '%s': conflictling key size %u != %lld.\n",
+					   map_name, map->def.key_size, sz);
+				return -EINVAL;
+			}
+			map->def.key_size = sz;
+			map->btf_key_type_id = t->type;
+		} else if (strcmp(name, "value_size") == 0) {
+			__u32 sz;
+
+			if (!get_map_field_int(map_name, obj->btf, def, m,
+					       def_data, &sz))
+				return -EINVAL;
+			pr_debug("map '%s': found value_size = %u.\n",
+				 map_name, sz);
+			if (map->def.value_size && map->def.value_size != sz) {
+				pr_warning("map '%s': conflictling value size %u != %u.\n",
+					   map_name, map->def.value_size, sz);
+				return -EINVAL;
+			}
+			map->def.value_size = sz;
+		} else if (strcmp(name, "value") == 0) {
+			__s64 sz;
+
+			t = btf__type_by_id(obj->btf, m->type);
+			if (!t) {
+				pr_warning("map '%s': value type [%d] not found.\n",
+					   map_name, m->type);
+				return -EINVAL;
+			}
+			if (BTF_INFO_KIND(t->info) != BTF_KIND_PTR) {
+				pr_warning("map '%s': value spec is not PTR: %u.\n",
+					   map_name, BTF_INFO_KIND(t->info));
+				return -EINVAL;
+			}
+			sz = btf__resolve_size(obj->btf, t->type);
+			if (sz < 0) {
+				pr_warning("map '%s': can't determine value size for type [%u]: %lld.\n",
+					   map_name, t->type, sz);
+				return sz;
+			}
+			pr_debug("map '%s': found value [%u], sz = %lld.\n",
+				 map_name, t->type, sz);
+			if (map->def.value_size && map->def.value_size != sz) {
+				pr_warning("map '%s': conflictling value size %u != %lld.\n",
+					   map_name, map->def.value_size, sz);
+				return -EINVAL;
+			}
+			map->def.value_size = sz;
+			map->btf_value_type_id = t->type;
+		} else {
+			if (strict) {
+				pr_warning("map '%s': unknown field '%s'.\n",
+					   map_name, name);
+				return -ENOTSUP;
+			}
+			pr_debug("map '%s': ignoring unknown field '%s'.\n",
+				 map_name, name);
+		}
+	}
+
+	if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
+		pr_warning("map '%s': map type isn't specified.\n", map_name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
+{
+	const struct btf_type *sec = NULL;
+	int nr_types, i, vlen, err;
+	const struct btf_type *t;
+	const char *name;
+	Elf_Data *data;
+	Elf_Scn *scn;
+
+	if (obj->efile.btf_maps_shndx < 0)
+		return 0;
+
+	scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
+	if (scn)
+		data = elf_getdata(scn, NULL);
+	if (!scn || !data) {
+		pr_warning("failed to get Elf_Data from map section %d (%s)\n",
+			   obj->efile.maps_shndx, MAPS_ELF_SEC);
+		return -EINVAL;
+	}
+
+	nr_types = btf__get_nr_types(obj->btf);
+	for (i = 1; i <= nr_types; i++) {
+		t = btf__type_by_id(obj->btf, i);
+		if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
+			continue;
+		name = btf__name_by_offset(obj->btf, t->name_off);
+		if (strcmp(name, MAPS_ELF_SEC) == 0) {
+			sec = t;
+			break;
+		}
+	}
+
+	if (!sec) {
+		pr_warning("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
+		return -ENOENT;
+	}
+
+	vlen = BTF_INFO_VLEN(sec->info);
+	for (i = 0; i < vlen; i++) {
+		err = bpf_object__init_user_btf_map(obj, sec, i,
+						    obj->efile.btf_maps_shndx,
+						    data, strict);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 static int bpf_object__init_maps(struct bpf_object *obj, int flags)
 {
 	bool strict = !(flags & MAPS_RELAX_COMPAT);
@@ -1016,6 +1324,10 @@ static int bpf_object__init_maps(struct bpf_object *obj, int flags)
 	if (err)
 		return err;
 
+	err = bpf_object__init_user_btf_maps(obj, strict);
+	if (err)
+		return err;
+
 	err = bpf_object__init_global_data_maps(obj);
 	if (err)
 		return err;
@@ -1113,10 +1425,16 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
 	}
 }
 
+static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
+{
+	return obj->efile.btf_maps_shndx >= 0;
+}
+
 static int bpf_object__init_btf(struct bpf_object *obj,
 				Elf_Data *btf_data,
 				Elf_Data *btf_ext_data)
 {
+	bool btf_required = bpf_object__is_btf_mandatory(obj);
 	int err = 0;
 
 	if (btf_data) {
@@ -1150,10 +1468,18 @@ static int bpf_object__init_btf(struct bpf_object *obj,
 	}
 out:
 	if (err || IS_ERR(obj->btf)) {
+		if (btf_required)
+			err = err ? : PTR_ERR(obj->btf);
+		else
+			err = 0;
 		if (!IS_ERR_OR_NULL(obj->btf))
 			btf__free(obj->btf);
 		obj->btf = NULL;
 	}
+	if (btf_required && !obj->btf) {
+		pr_warning("BTF is required, but is missing or corrupted.\n");
+		return err == 0 ? -ENOENT : err;
+	}
 	return 0;
 }
 
@@ -1173,6 +1499,8 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
 			   BTF_ELF_SEC, err);
 		btf__free(obj->btf);
 		obj->btf = NULL;
+		if (bpf_object__is_btf_mandatory(obj))
+			return err;
 	}
 	return 0;
 }
@@ -1236,6 +1564,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 				return err;
 		} else if (strcmp(name, "maps") == 0) {
 			obj->efile.maps_shndx = idx;
+		} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
+			obj->efile.btf_maps_shndx = idx;
 		} else if (strcmp(name, BTF_ELF_SEC) == 0) {
 			btf_data = data;
 		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
@@ -1355,7 +1685,8 @@ static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
 static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
 				      int shndx)
 {
-	return shndx == obj->efile.maps_shndx;
+	return shndx == obj->efile.maps_shndx ||
+	       shndx == obj->efile.btf_maps_shndx;
 }
 
 static bool bpf_object__relo_in_known_section(const struct bpf_object *obj,
@@ -1399,14 +1730,14 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 	prog->nr_reloc = nrels;
 
 	for (i = 0; i < nrels; i++) {
-		GElf_Sym sym;
-		GElf_Rel rel;
-		unsigned int insn_idx;
-		unsigned int shdr_idx;
 		struct bpf_insn *insns = prog->insns;
 		enum libbpf_map_type type;
+		unsigned int insn_idx;
+		unsigned int shdr_idx;
 		const char *name;
 		size_t map_idx;
+		GElf_Sym sym;
+		GElf_Rel rel;
 
 		if (!gelf_getrel(data, i, &rel)) {
 			pr_warning("relocation: failed to get %d reloc\n", i);
@@ -1500,14 +1831,18 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 	return 0;
 }
 
-static int bpf_map_find_btf_info(struct bpf_map *map, const struct btf *btf)
+static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
 {
 	struct bpf_map_def *def = &map->def;
 	__u32 key_type_id = 0, value_type_id = 0;
 	int ret;
 
+	/* if it's BTF-defined map, we don't need to search for type IDs */
+	if (map->sec_idx == obj->efile.btf_maps_shndx)
+		return 0;
+
 	if (!bpf_map__is_internal(map)) {
-		ret = btf__get_map_kv_tids(btf, map->name, def->key_size,
+		ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
 					   def->value_size, &key_type_id,
 					   &value_type_id);
 	} else {
@@ -1515,7 +1850,7 @@ static int bpf_map_find_btf_info(struct bpf_map *map, const struct btf *btf)
 		 * LLVM annotates global data differently in BTF, that is,
 		 * only as '.data', '.bss' or '.rodata'.
 		 */
-		ret = btf__find_by_name(btf,
+		ret = btf__find_by_name(obj->btf,
 				libbpf_type_to_btf_name[map->libbpf_type]);
 	}
 	if (ret < 0)
@@ -1805,7 +2140,7 @@ bpf_object__create_maps(struct bpf_object *obj)
 		    map->inner_map_fd >= 0)
 			create_attr.inner_map_fd = map->inner_map_fd;
 
-		if (obj->btf && !bpf_map_find_btf_info(map, obj->btf)) {
+		if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
 			create_attr.btf_fd = btf__fd(obj->btf);
 			create_attr.btf_key_type_id = map->btf_key_type_id;
 			create_attr.btf_value_type_id = map->btf_value_type_id;
-- 
cgit v1.2.3-55-g7522


From a324aae32fa9bfdd03e89078e20ebcbd7737fda5 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko
Date: Mon, 17 Jun 2019 15:48:58 -0700
Subject: libbpf: constify getter APIs

Add const qualifiers to bpf_object/bpf_program/bpf_map arguments for
getter APIs. There is no need for them to not be const pointers.

Verified that

make -C tools/lib/bpf
make -C tools/testing/selftests/bpf
make -C tools/perf

all build without warnings.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/lib/bpf/libbpf.c | 80 ++++++++++++++++++++++++++------------------------
 tools/lib/bpf/libbpf.h | 62 +++++++++++++++++++-------------------
 2 files changed, 72 insertions(+), 70 deletions(-)

(limited to 'tools/lib/bpf/libbpf.c')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 585e3a2f1eb4..8ce3beba8551 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1663,7 +1663,8 @@ bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 }
 
 struct bpf_program *
-bpf_object__find_program_by_title(struct bpf_object *obj, const char *title)
+bpf_object__find_program_by_title(const struct bpf_object *obj,
+				  const char *title)
 {
 	struct bpf_program *pos;
 
@@ -2589,8 +2590,8 @@ out:
 	return err;
 }
 
-static bool bpf_program__is_function_storage(struct bpf_program *prog,
-					     struct bpf_object *obj)
+static bool bpf_program__is_function_storage(const struct bpf_program *prog,
+					     const struct bpf_object *obj)
 {
 	return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
 }
@@ -3296,17 +3297,17 @@ bpf_object__next(struct bpf_object *prev)
 	return next;
 }
 
-const char *bpf_object__name(struct bpf_object *obj)
+const char *bpf_object__name(const struct bpf_object *obj)
 {
 	return obj ? obj->path : ERR_PTR(-EINVAL);
 }
 
-unsigned int bpf_object__kversion(struct bpf_object *obj)
+unsigned int bpf_object__kversion(const struct bpf_object *obj)
 {
 	return obj ? obj->kern_version : 0;
 }
 
-struct btf *bpf_object__btf(struct bpf_object *obj)
+struct btf *bpf_object__btf(const struct bpf_object *obj)
 {
 	return obj ? obj->btf : NULL;
 }
@@ -3327,13 +3328,14 @@ int bpf_object__set_priv(struct bpf_object *obj, void *priv,
 	return 0;
 }
 
-void *bpf_object__priv(struct bpf_object *obj)
+void *bpf_object__priv(const struct bpf_object *obj)
 {
 	return obj ? obj->priv : ERR_PTR(-EINVAL);
 }
 
 static struct bpf_program *
-__bpf_program__iter(struct bpf_program *p, struct bpf_object *obj, bool forward)
+__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
+		    bool forward)
 {
 	size_t nr_programs = obj->nr_programs;
 	ssize_t idx;
@@ -3358,7 +3360,7 @@ __bpf_program__iter(struct bpf_program *p, struct bpf_object *obj, bool forward)
 }
 
 struct bpf_program *
-bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
+bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
 {
 	struct bpf_program *prog = prev;
 
@@ -3370,7 +3372,7 @@ bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
 }
 
 struct bpf_program *
-bpf_program__prev(struct bpf_program *next, struct bpf_object *obj)
+bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
 {
 	struct bpf_program *prog = next;
 
@@ -3392,7 +3394,7 @@ int bpf_program__set_priv(struct bpf_program *prog, void *priv,
 	return 0;
 }
 
-void *bpf_program__priv(struct bpf_program *prog)
+void *bpf_program__priv(const struct bpf_program *prog)
 {
 	return prog ? prog->priv : ERR_PTR(-EINVAL);
 }
@@ -3402,7 +3404,7 @@ void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
 	prog->prog_ifindex = ifindex;
 }
 
-const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
+const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
 {
 	const char *title;
 
@@ -3418,7 +3420,7 @@ const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
 	return title;
 }
 
-int bpf_program__fd(struct bpf_program *prog)
+int bpf_program__fd(const struct bpf_program *prog)
 {
 	return bpf_program__nth_fd(prog, 0);
 }
@@ -3451,7 +3453,7 @@ int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
 	return 0;
 }
 
-int bpf_program__nth_fd(struct bpf_program *prog, int n)
+int bpf_program__nth_fd(const struct bpf_program *prog, int n)
 {
 	int fd;
 
@@ -3479,25 +3481,25 @@ void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
 	prog->type = type;
 }
 
-static bool bpf_program__is_type(struct bpf_program *prog,
+static bool bpf_program__is_type(const struct bpf_program *prog,
 				 enum bpf_prog_type type)
 {
 	return prog ? (prog->type == type) : false;
 }
 
-#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);	\
-}							\
+#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(const 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);
@@ -3692,17 +3694,17 @@ bpf_program__identify_section(struct bpf_program *prog,
 					expected_attach_type);
 }
 
-int bpf_map__fd(struct bpf_map *map)
+int bpf_map__fd(const struct bpf_map *map)
 {
 	return map ? map->fd : -EINVAL;
 }
 
-const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
+const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
 {
 	return map ? &map->def : ERR_PTR(-EINVAL);
 }
 
-const char *bpf_map__name(struct bpf_map *map)
+const char *bpf_map__name(const struct bpf_map *map)
 {
 	return map ? map->name : NULL;
 }
@@ -3733,17 +3735,17 @@ int bpf_map__set_priv(struct bpf_map *map, void *priv,
 	return 0;
 }
 
-void *bpf_map__priv(struct bpf_map *map)
+void *bpf_map__priv(const struct bpf_map *map)
 {
 	return map ? map->priv : ERR_PTR(-EINVAL);
 }
 
-bool bpf_map__is_offload_neutral(struct bpf_map *map)
+bool bpf_map__is_offload_neutral(const struct bpf_map *map)
 {
 	return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
 }
 
-bool bpf_map__is_internal(struct bpf_map *map)
+bool bpf_map__is_internal(const struct bpf_map *map)
 {
 	return map->libbpf_type != LIBBPF_MAP_UNSPEC;
 }
@@ -3768,7 +3770,7 @@ int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
 }
 
 static struct bpf_map *
-__bpf_map__iter(struct bpf_map *m, struct bpf_object *obj, int i)
+__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
 {
 	ssize_t idx;
 	struct bpf_map *s, *e;
@@ -3792,7 +3794,7 @@ __bpf_map__iter(struct bpf_map *m, struct bpf_object *obj, int i)
 }
 
 struct bpf_map *
-bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
+bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
 {
 	if (prev == NULL)
 		return obj->maps;
@@ -3801,7 +3803,7 @@ bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
 }
 
 struct bpf_map *
-bpf_map__prev(struct bpf_map *next, struct bpf_object *obj)
+bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
 {
 	if (next == NULL) {
 		if (!obj->nr_maps)
@@ -3813,7 +3815,7 @@ bpf_map__prev(struct bpf_map *next, struct bpf_object *obj)
 }
 
 struct bpf_map *
-bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
+bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
 {
 	struct bpf_map *pos;
 
@@ -3825,7 +3827,7 @@ bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
 }
 
 int
-bpf_object__find_map_fd_by_name(struct bpf_object *obj, const char *name)
+bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
 {
 	return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
 }
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 2e594a0fa961..d639f47e3110 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -98,15 +98,16 @@ struct bpf_object_load_attr {
 LIBBPF_API int bpf_object__load(struct bpf_object *obj);
 LIBBPF_API int bpf_object__load_xattr(struct bpf_object_load_attr *attr);
 LIBBPF_API int bpf_object__unload(struct bpf_object *obj);
-LIBBPF_API const char *bpf_object__name(struct bpf_object *obj);
-LIBBPF_API unsigned int bpf_object__kversion(struct bpf_object *obj);
+LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);
+LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);
 
 struct btf;
-LIBBPF_API struct btf *bpf_object__btf(struct bpf_object *obj);
+LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj);
 LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
 
 LIBBPF_API struct bpf_program *
-bpf_object__find_program_by_title(struct bpf_object *obj, const char *title);
+bpf_object__find_program_by_title(const struct bpf_object *obj,
+				  const char *title);
 
 LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev);
 #define bpf_object__for_each_safe(pos, tmp)			\
@@ -118,7 +119,7 @@ LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev);
 typedef void (*bpf_object_clear_priv_t)(struct bpf_object *, void *);
 LIBBPF_API int bpf_object__set_priv(struct bpf_object *obj, void *priv,
 				    bpf_object_clear_priv_t clear_priv);
-LIBBPF_API void *bpf_object__priv(struct bpf_object *prog);
+LIBBPF_API void *bpf_object__priv(const struct bpf_object *prog);
 
 LIBBPF_API int
 libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
@@ -129,7 +130,7 @@ LIBBPF_API int libbpf_attach_type_by_name(const char *name,
 /* Accessors of bpf_program */
 struct bpf_program;
 LIBBPF_API struct bpf_program *bpf_program__next(struct bpf_program *prog,
-						 struct bpf_object *obj);
+						 const struct bpf_object *obj);
 
 #define bpf_object__for_each_program(pos, obj)		\
 	for ((pos) = bpf_program__next(NULL, (obj));	\
@@ -137,24 +138,23 @@ LIBBPF_API struct bpf_program *bpf_program__next(struct bpf_program *prog,
 	     (pos) = bpf_program__next((pos), (obj)))
 
 LIBBPF_API struct bpf_program *bpf_program__prev(struct bpf_program *prog,
-						 struct bpf_object *obj);
+						 const struct bpf_object *obj);
 
-typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
-					 void *);
+typedef void (*bpf_program_clear_priv_t)(struct bpf_program *, void *);
 
 LIBBPF_API int bpf_program__set_priv(struct bpf_program *prog, void *priv,
 				     bpf_program_clear_priv_t clear_priv);
 
-LIBBPF_API void *bpf_program__priv(struct bpf_program *prog);
+LIBBPF_API void *bpf_program__priv(const struct bpf_program *prog);
 LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,
 					 __u32 ifindex);
 
-LIBBPF_API const char *bpf_program__title(struct bpf_program *prog,
+LIBBPF_API const char *bpf_program__title(const struct bpf_program *prog,
 					  bool needs_copy);
 
 LIBBPF_API int bpf_program__load(struct bpf_program *prog, char *license,
 				 __u32 kern_version);
-LIBBPF_API int bpf_program__fd(struct bpf_program *prog);
+LIBBPF_API int bpf_program__fd(const struct bpf_program *prog);
 LIBBPF_API int bpf_program__pin_instance(struct bpf_program *prog,
 					 const char *path,
 					 int instance);
@@ -227,7 +227,7 @@ typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
 LIBBPF_API int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
 				     bpf_program_prep_t prep);
 
-LIBBPF_API int bpf_program__nth_fd(struct bpf_program *prog, int n);
+LIBBPF_API int bpf_program__nth_fd(const struct bpf_program *prog, int n);
 
 /*
  * Adjust type of BPF program. Default is kprobe.
@@ -246,14 +246,14 @@ LIBBPF_API void
 bpf_program__set_expected_attach_type(struct bpf_program *prog,
 				      enum bpf_attach_type type);
 
-LIBBPF_API bool bpf_program__is_socket_filter(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_tracepoint(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_raw_tracepoint(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_kprobe(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_sched_cls(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_sched_act(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_xdp(struct bpf_program *prog);
-LIBBPF_API bool bpf_program__is_perf_event(struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_socket_filter(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_tracepoint(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_raw_tracepoint(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_kprobe(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_sched_cls(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_sched_act(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_xdp(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__is_perf_event(const struct bpf_program *prog);
 
 /*
  * No need for __attribute__((packed)), all members of 'bpf_map_def'
@@ -275,10 +275,10 @@ struct bpf_map_def {
  */
 struct bpf_map;
 LIBBPF_API struct bpf_map *
-bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);
+bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name);
 
 LIBBPF_API int
-bpf_object__find_map_fd_by_name(struct bpf_object *obj, const char *name);
+bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name);
 
 /*
  * Get bpf_map through the offset of corresponding struct bpf_map_def
@@ -288,7 +288,7 @@ LIBBPF_API struct bpf_map *
 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset);
 
 LIBBPF_API struct bpf_map *
-bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
+bpf_map__next(const struct bpf_map *map, const struct bpf_object *obj);
 #define bpf_object__for_each_map(pos, obj)		\
 	for ((pos) = bpf_map__next(NULL, (obj));	\
 	     (pos) != NULL;				\
@@ -296,22 +296,22 @@ bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
 #define bpf_map__for_each bpf_object__for_each_map
 
 LIBBPF_API struct bpf_map *
-bpf_map__prev(struct bpf_map *map, struct bpf_object *obj);
+bpf_map__prev(const struct bpf_map *map, const struct bpf_object *obj);
 
-LIBBPF_API int bpf_map__fd(struct bpf_map *map);
-LIBBPF_API const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
-LIBBPF_API const char *bpf_map__name(struct bpf_map *map);
+LIBBPF_API int bpf_map__fd(const struct bpf_map *map);
+LIBBPF_API const struct bpf_map_def *bpf_map__def(const struct bpf_map *map);
+LIBBPF_API const char *bpf_map__name(const struct bpf_map *map);
 LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
 LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
 
 typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
 LIBBPF_API int bpf_map__set_priv(struct bpf_map *map, void *priv,
 				 bpf_map_clear_priv_t clear_priv);
-LIBBPF_API void *bpf_map__priv(struct bpf_map *map);
+LIBBPF_API void *bpf_map__priv(const struct bpf_map *map);
 LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
 LIBBPF_API int bpf_map__resize(struct bpf_map *map, __u32 max_entries);
-LIBBPF_API bool bpf_map__is_offload_neutral(struct bpf_map *map);
-LIBBPF_API bool bpf_map__is_internal(struct bpf_map *map);
+LIBBPF_API bool bpf_map__is_offload_neutral(const struct bpf_map *map);
+LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
 LIBBPF_API void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
 LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
 LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
-- 
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