Remove support for legacy features and behaviors that previously had to
be disabled by calling libbpf_set_strict_mode():
- legacy BPF map definitions are not supported now;
- RLIMIT_MEMLOCK auto-setting, if necessary, is always on (but see
libbpf_set_memlock_rlim());
- program name is used for program pinning (instead of section name);
- cleaned up error returning logic;
- entry BPF programs should have SEC() always.
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
tools/lib/bpf/bpf.c | 4 -
tools/lib/bpf/libbpf.c | 212 ++------------------------------
tools/lib/bpf/libbpf.h | 34 -----
tools/lib/bpf/libbpf_internal.h | 24 +---
tools/lib/bpf/libbpf_legacy.h | 24 ++++
5 files changed, 37 insertions(+), 261 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 2f3495d80d69..6d848b02c1e0 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -147,10 +147,6 @@ int bump_rlimit_memlock(void)
{
struct rlimit rlim;
- /* this the default in libbpf 1.0, but for now user has to opt-in explicitly */
- if (!(libbpf_mode & LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK))
- return 0;
-
/* if kernel supports memcg-based accounting, skip bumping RLIMIT_MEMLOCK */
if (memlock_bumped || kernel_supports(NULL, FEAT_MEMCG_ACCOUNT))
return 0;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9287554fe6a8..e867522cf506 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -278,12 +278,9 @@ static inline __u64 ptr_to_u64(const void *ptr)
return (__u64) (unsigned long) ptr;
}
-/* this goes away in libbpf 1.0 */
-enum libbpf_strict_mode libbpf_mode = LIBBPF_STRICT_NONE;
-
int libbpf_set_strict_mode(enum libbpf_strict_mode mode)
{
- libbpf_mode = mode;
+ /* as of v1.0 libbpf_set_strict_mode() is a no-op */
return 0;
}
@@ -367,9 +364,10 @@ struct bpf_sec_def {
* linux/filter.h.
*/
struct bpf_program {
- const struct bpf_sec_def *sec_def;
+ char *name;
char *sec_name;
size_t sec_idx;
+ const struct bpf_sec_def *sec_def;
/* this program's instruction offset (in number of instructions)
* within its containing ELF section
*/
@@ -389,12 +387,6 @@ struct bpf_program {
*/
size_t sub_insn_off;
- char *name;
- /* name with / replaced by _; makes recursive pinning
- * in bpf_object__pin_programs easier
- */
- char *pin_name;
-
/* instructions that belong to BPF program; insns[0] is located at
* sec_insn_off instruction within its ELF section in ELF file, so
* when mapping ELF file instruction index to the local instruction,
@@ -695,7 +687,6 @@ static void bpf_program__exit(struct bpf_program *prog)
bpf_program__unload(prog);
zfree(&prog->name);
zfree(&prog->sec_name);
- zfree(&prog->pin_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
@@ -704,26 +695,6 @@ static void bpf_program__exit(struct bpf_program *prog)
prog->sec_idx = -1;
}
-static char *__bpf_program__pin_name(struct bpf_program *prog)
-{
- char *name, *p;
-
- if (libbpf_mode & LIBBPF_STRICT_SEC_NAME)
- name = strdup(prog->name);
- else
- name = strdup(prog->sec_name);
-
- if (!name)
- return NULL;
-
- p = name;
-
- while ((p = strchr(p, '/')))
- *p = '_';
-
- return name;
-}
-
static bool insn_is_subprog_call(const struct bpf_insn *insn)
{
return BPF_CLASS(insn->code) == BPF_JMP &&
@@ -790,10 +761,6 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog,
if (!prog->name)
goto errout;
- prog->pin_name = __bpf_program__pin_name(prog);
- if (!prog->pin_name)
- goto errout;
-
prog->insns = malloc(insn_data_sz);
if (!prog->insns)
goto errout;
@@ -2007,143 +1974,6 @@ static int bpf_object__init_kconfig_map(struct bpf_object *obj)
return 0;
}
-static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
-{
- Elf_Data *symbols = obj->efile.symbols;
- int i, map_def_sz = 0, nr_maps = 0, nr_syms;
- Elf_Data *data = NULL;
- Elf_Scn *scn;
-
- if (obj->efile.maps_shndx < 0)
- return 0;
-
- if (libbpf_mode & LIBBPF_STRICT_MAP_DEFINITIONS) {
- pr_warn("legacy map definitions in SEC(\"maps\") are not supported\n");
- return -EOPNOTSUPP;
- }
-
- if (!symbols)
- return -EINVAL;
-
- scn = elf_sec_by_idx(obj, obj->efile.maps_shndx);
- data = elf_sec_data(obj, scn);
- if (!scn || !data) {
- pr_warn("elf: failed to get legacy map definitions for %s\n",
- obj->path);
- 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.
- */
- nr_syms = symbols->d_size / sizeof(Elf64_Sym);
- for (i = 0; i < nr_syms; i++) {
- Elf64_Sym *sym = elf_sym_by_idx(obj, i);
-
- if (sym->st_shndx != obj->efile.maps_shndx)
- continue;
- if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION)
- continue;
- nr_maps++;
- }
- /* Assume equally sized map definitions */
- pr_debug("elf: found %d legacy map definitions (%zd bytes) in %s\n",
- nr_maps, data->d_size, obj->path);
-
- if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
- pr_warn("elf: unable to determine legacy map definition size in %s\n",
- obj->path);
- return -EINVAL;
- }
- map_def_sz = data->d_size / nr_maps;
-
- /* Fill obj->maps using data in "maps" section. */
- for (i = 0; i < nr_syms; i++) {
- Elf64_Sym *sym = elf_sym_by_idx(obj, i);
- const char *map_name;
- struct bpf_map_def *def;
- struct bpf_map *map;
-
- if (sym->st_shndx != obj->efile.maps_shndx)
- continue;
- if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION)
- continue;
-
- map = bpf_object__add_map(obj);
- if (IS_ERR(map))
- return PTR_ERR(map);
-
- map_name = elf_sym_str(obj, sym->st_name);
- if (!map_name) {
- pr_warn("failed to get map #%d name sym string for obj %s\n",
- i, obj->path);
- return -LIBBPF_ERRNO__FORMAT;
- }
-
- pr_warn("map '%s' (legacy): legacy map definitions are deprecated, use BTF-defined maps instead\n", map_name);
-
- if (ELF64_ST_BIND(sym->st_info) == STB_LOCAL) {
- pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
- return -ENOTSUP;
- }
-
- map->libbpf_type = LIBBPF_MAP_UNSPEC;
- 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_warn("corrupted maps section in %s: last map \"%s\" too small\n",
- obj->path, map_name);
- return -EINVAL;
- }
-
- map->name = strdup(map_name);
- if (!map->name) {
- pr_warn("map '%s': failed to alloc map name\n", map_name);
- return -ENOMEM;
- }
- 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
- * bpf_map_def, copy it. Any extra fields in our version
- * of bpf_map_def will default to zero as a result of the
- * calloc above.
- */
- if (map_def_sz <= sizeof(struct bpf_map_def)) {
- memcpy(&map->def, def, map_def_sz);
- } else {
- /*
- * Here the map structure being read is bigger than what
- * we expect, truncate if the excess bits are all zero.
- * If they are not zero, reject this map as
- * incompatible.
- */
- char *b;
-
- for (b = ((char *)def) + sizeof(struct bpf_map_def);
- b < ((char *)def) + map_def_sz; b++) {
- if (*b != 0) {
- pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
- obj->path, map_name);
- if (strict)
- return -EINVAL;
- }
- }
- memcpy(&map->def, def, sizeof(struct bpf_map_def));
- }
-
- /* btf info may not exist but fill it in if it does exist */
- (void) bpf_map_find_btf_info(obj, map);
- }
- return 0;
-}
-
const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
{
@@ -2699,12 +2529,11 @@ static int bpf_object__init_maps(struct bpf_object *obj,
{
const char *pin_root_path;
bool strict;
- int err;
+ int err = 0;
strict = !OPTS_GET(opts, relaxed_maps, false);
pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
- err = bpf_object__init_user_maps(obj, strict);
err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
err = err ?: bpf_object__init_global_data_maps(obj);
err = err ?: bpf_object__init_kconfig_map(obj);
@@ -3945,28 +3774,8 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
return 0;
}
-static bool prog_is_subprog(const struct bpf_object *obj,
- const struct bpf_program *prog)
-{
- /* For legacy reasons, libbpf supports an entry-point BPF programs
- * without SEC() attribute, i.e., those in the .text section. But if
- * there are 2 or more such programs in the .text section, they all
- * must be subprograms called from entry-point BPF programs in
- * designated SEC()'tions, otherwise there is no way to distinguish
- * which of those programs should be loaded vs which are a subprogram.
- * Similarly, if there is a function/program in .text and at least one
- * other BPF program with custom SEC() attribute, then we just assume
- * .text programs are subprograms (even if they are not called from
- * other programs), because libbpf never explicitly supported mixing
- * SEC()-designated BPF programs and .text entry-point BPF programs.
- *
- * In libbpf 1.0 strict mode, we always consider .text
- * programs to be subprograms.
- */
-
- if (libbpf_mode & LIBBPF_STRICT_SEC_NAME)
- return prog->sec_idx == obj->efile.text_shndx;
-
+static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog)
+{
return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1;
}
@@ -8184,8 +7993,7 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
char buf[PATH_MAX];
int len;
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- prog->pin_name);
+ len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
if (len < 0) {
err = -EINVAL;
goto err_unpin_programs;
@@ -8206,8 +8014,7 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
char buf[PATH_MAX];
int len;
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- prog->pin_name);
+ len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
if (len < 0)
continue;
else if (len >= PATH_MAX)
@@ -8231,8 +8038,7 @@ int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
char buf[PATH_MAX];
int len;
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- prog->pin_name);
+ len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
if (len < 0)
return libbpf_err(-EINVAL);
else if (len >= PATH_MAX)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 5eb3145b8945..e4d5353f757b 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -886,40 +886,6 @@ LIBBPF_API int bpf_map__lookup_and_delete_elem(const struct bpf_map *map,
LIBBPF_API int bpf_map__get_next_key(const struct bpf_map *map,
const void *cur_key, void *next_key, size_t key_sz);
-/**
- * @brief **libbpf_get_error()** extracts the error code from the passed
- * pointer
- * @param ptr pointer returned from libbpf API function
- * @return error code; or 0 if no error occured
- *
- * Many libbpf API functions which return pointers have logic to encode error
- * codes as pointers, and do not return NULL. Meaning **libbpf_get_error()**
- * should be used on the return value from these functions immediately after
- * calling the API function, with no intervening calls that could clobber the
- * `errno` variable. Consult the individual functions documentation to verify
- * if this logic applies should be used.
- *
- * For these API functions, if `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)`
- * is enabled, NULL is returned on error instead.
- *
- * If ptr is NULL, then errno should be already set by the failing
- * API, because libbpf never returns NULL on success and it now always
- * sets errno on error.
- *
- * Example usage:
- *
- * struct perf_buffer *pb;
- *
- * pb = perf_buffer__new(bpf_map__fd(obj->maps.events), PERF_BUFFER_PAGES, &opts);
- * err = libbpf_get_error(pb);
- * if (err) {
- * pb = NULL;
- * fprintf(stderr, "failed to open perf buffer: %d\n", err);
- * goto cleanup;
- * }
- */
-LIBBPF_API long libbpf_get_error(const void *ptr);
-
struct bpf_xdp_set_link_opts {
size_t sz;
int old_fd;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index ef5d975078e5..01373551e0eb 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -15,7 +15,6 @@
#include <linux/err.h>
#include <fcntl.h>
#include <unistd.h>
-#include "libbpf_legacy.h"
#include "relo_core.h"
/* make sure libbpf doesn't use kernel-only integer typedefs */
@@ -476,8 +475,6 @@ int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void
__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
__u32 kind);
-extern enum libbpf_strict_mode libbpf_mode;
-
typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type,
const char *sym_name, void *ctx);
@@ -496,12 +493,8 @@ static inline int libbpf_err(int ret)
*/
static inline int libbpf_err_errno(int ret)
{
- if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS)
- /* errno is already assumed to be set on error */
- return ret < 0 ? -errno : ret;
-
- /* legacy: on error return -1 directly and don't touch errno */
- return ret;
+ /* errno is already assumed to be set on error */
+ return ret < 0 ? -errno : ret;
}
/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
@@ -509,12 +502,7 @@ static inline void *libbpf_err_ptr(int err)
{
/* set errno on error, this doesn't break anything */
errno = -err;
-
- if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
- return NULL;
-
- /* legacy: encode err as ptr */
- return ERR_PTR(err);
+ return NULL;
}
/* handle pointer-returning APIs' error handling */
@@ -524,11 +512,7 @@ static inline void *libbpf_ptr(void *ret)
if (IS_ERR(ret))
errno = -PTR_ERR(ret);
- if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
- return IS_ERR(ret) ? NULL : ret;
-
- /* legacy: pass-through original pointer */
- return ret;
+ return IS_ERR(ret) ? NULL : ret;
}
static inline bool str_is_empty(const char *s)
diff --git a/tools/lib/bpf/libbpf_legacy.h b/tools/lib/bpf/libbpf_legacy.h
index d7bcbd01f66f..863f49df8bf4 100644
--- a/tools/lib/bpf/libbpf_legacy.h
+++ b/tools/lib/bpf/libbpf_legacy.h
@@ -20,6 +20,11 @@
extern "C" {
#endif
+/* As of libbpf 1.0 libbpf_set_strict_mode() and enum libbpf_struct_mode have
+ * no effect. But they are left in libbpf_legacy.h so that applications that
+ * prepared for libbpf 1.0 before final release by using
+ * libbpf_set_strict_mode() still work with libbpf 1.0+ without any changes.
+ */
enum libbpf_strict_mode {
/* Turn on all supported strict features of libbpf to simulate libbpf
* v1.0 behavior.
@@ -88,6 +93,25 @@ enum libbpf_strict_mode {
LIBBPF_API int libbpf_set_strict_mode(enum libbpf_strict_mode mode);
+/**
+ * @brief **libbpf_get_error()** extracts the error code from the passed
+ * pointer
+ * @param ptr pointer returned from libbpf API function
+ * @return error code; or 0 if no error occured
+ *
+ * Note, as of libbpf 1.0 this function is not necessary and not recommended
+ * to be used. Libbpf doesn't return error code embedded into the pointer
+ * itself. Instead, NULL is returned on error and error code is passed through
+ * thread-local errno variable. **libbpf_get_error()** is just returning -errno
+ * value if it receives NULL, which is correct only if errno hasn't been
+ * modified between libbpf API call and corresponding **libbpf_get_error()**
+ * call. Prefer to check return for NULL and use errno directly.
+ *
+ * This API is left in libbpf 1.0 to allow applications that were 1.0-ready
+ * before final libbpf 1.0 without needing to change them.
+ */
+LIBBPF_API long libbpf_get_error(const void *ptr);
+
#define DECLARE_LIBBPF_OPTS LIBBPF_OPTS
/* "Discouraged" APIs which don't follow consistent libbpf naming patterns.
--
2.30.2
