blob: 7469c7dcc15e71fb82e0c8d0a1426cce7b7e2127 [file] [log] [blame]
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/*
* Common eBPF ELF object loading operations.
*
* 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.
* Copyright (C) 2019 Isovalent, Inc.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <libgen.h>
#include <inttypes.h>
#include <limits.h>
#include <string.h>
#include <unistd.h>
#include <endian.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <asm/unistd.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/filter.h>
#include <linux/list.h>
#include <linux/limits.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include <linux/version.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <sys/utsname.h>
#include <sys/resource.h>
#include <tools/libc_compat.h>
#include <libelf.h>
#include <gelf.h>
#include <zlib.h>
#include "libbpf.h"
#include "bpf.h"
#include "btf.h"
#include "str_error.h"
#include "libbpf_internal.h"
#include "hashmap.h"
/* make sure libbpf doesn't use kernel-only integer typedefs */
#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
#ifndef EM_BPF
#define EM_BPF 247
#endif
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
#endif
/* vsprintf() in __base_pr() uses nonliteral format string. It may break
* compilation if user enables corresponding warning. Disable it explicitly.
*/
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#define __printf(a, b) __attribute__((format(printf, a, b)))
static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
static struct bpf_program *bpf_object__find_prog_by_idx(struct bpf_object *obj,
int idx);
static const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
static int __base_pr(enum libbpf_print_level level, const char *format,
va_list args)
{
if (level == LIBBPF_DEBUG)
return 0;
return vfprintf(stderr, format, args);
}
static libbpf_print_fn_t __libbpf_pr = __base_pr;
libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
{
libbpf_print_fn_t old_print_fn = __libbpf_pr;
__libbpf_pr = fn;
return old_print_fn;
}
__printf(2, 3)
void libbpf_print(enum libbpf_print_level level, const char *format, ...)
{
va_list args;
if (!__libbpf_pr)
return;
va_start(args, format);
__libbpf_pr(level, format, args);
va_end(args);
}
static void pr_perm_msg(int err)
{
struct rlimit limit;
char buf[100];
if (err != -EPERM || geteuid() != 0)
return;
err = getrlimit(RLIMIT_MEMLOCK, &limit);
if (err)
return;
if (limit.rlim_cur == RLIM_INFINITY)
return;
if (limit.rlim_cur < 1024)
snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
else if (limit.rlim_cur < 1024*1024)
snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
else
snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024));
pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n",
buf);
}
#define STRERR_BUFSIZE 128
/* Copied from tools/perf/util/util.h */
#ifndef zfree
# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
#endif
#ifndef zclose
# define zclose(fd) ({ \
int ___err = 0; \
if ((fd) >= 0) \
___err = close((fd)); \
fd = -1; \
___err; })
#endif
#ifdef HAVE_LIBELF_MMAP_SUPPORT
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
#else
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
#endif
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
struct bpf_capabilities {
/* v4.14: kernel support for program & map names. */
__u32 name:1;
/* v5.2: kernel support for global data sections. */
__u32 global_data:1;
/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
__u32 btf_func:1;
/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
__u32 btf_datasec:1;
/* BPF_F_MMAPABLE is supported for arrays */
__u32 array_mmap:1;
/* BTF_FUNC_GLOBAL is supported */
__u32 btf_func_global:1;
};
enum reloc_type {
RELO_LD64,
RELO_CALL,
RELO_DATA,
RELO_EXTERN,
};
struct reloc_desc {
enum reloc_type type;
int insn_idx;
int map_idx;
int sym_off;
};
/*
* bpf_prog should be a better name but it has been used in
* linux/filter.h.
*/
struct bpf_program {
/* Index in elf obj file, for relocation use. */
int idx;
char *name;
int prog_ifindex;
char *section_name;
/* section_name with / replaced by _; makes recursive pinning
* in bpf_object__pin_programs easier
*/
char *pin_name;
struct bpf_insn *insns;
size_t insns_cnt, main_prog_cnt;
enum bpf_prog_type type;
struct reloc_desc *reloc_desc;
int nr_reloc;
int log_level;
struct {
int nr;
int *fds;
} instances;
bpf_program_prep_t preprocessor;
struct bpf_object *obj;
void *priv;
bpf_program_clear_priv_t clear_priv;
enum bpf_attach_type expected_attach_type;
__u32 attach_btf_id;
__u32 attach_prog_fd;
void *func_info;
__u32 func_info_rec_size;
__u32 func_info_cnt;
struct bpf_capabilities *caps;
void *line_info;
__u32 line_info_rec_size;
__u32 line_info_cnt;
__u32 prog_flags;
};
struct bpf_struct_ops {
const char *tname;
const struct btf_type *type;
struct bpf_program **progs;
__u32 *kern_func_off;
/* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
void *data;
/* e.g. struct bpf_struct_ops_tcp_congestion_ops in
* btf_vmlinux's format.
* struct bpf_struct_ops_tcp_congestion_ops {
* [... some other kernel fields ...]
* struct tcp_congestion_ops data;
* }
* kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops)
* bpf_map__init_kern_struct_ops() will populate the "kern_vdata"
* from "data".
*/
void *kern_vdata;
__u32 type_id;
};
#define DATA_SEC ".data"
#define BSS_SEC ".bss"
#define RODATA_SEC ".rodata"
#define KCONFIG_SEC ".kconfig"
#define STRUCT_OPS_SEC ".struct_ops"
enum libbpf_map_type {
LIBBPF_MAP_UNSPEC,
LIBBPF_MAP_DATA,
LIBBPF_MAP_BSS,
LIBBPF_MAP_RODATA,
LIBBPF_MAP_KCONFIG,
};
static const char * const libbpf_type_to_btf_name[] = {
[LIBBPF_MAP_DATA] = DATA_SEC,
[LIBBPF_MAP_BSS] = BSS_SEC,
[LIBBPF_MAP_RODATA] = RODATA_SEC,
[LIBBPF_MAP_KCONFIG] = KCONFIG_SEC,
};
struct bpf_map {
char *name;
int fd;
int sec_idx;
size_t sec_offset;
int map_ifindex;
int inner_map_fd;
struct bpf_map_def def;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
__u32 btf_vmlinux_value_type_id;
void *priv;
bpf_map_clear_priv_t clear_priv;
enum libbpf_map_type libbpf_type;
void *mmaped;
struct bpf_struct_ops *st_ops;
char *pin_path;
bool pinned;
bool reused;
};
enum extern_type {
EXT_UNKNOWN,
EXT_CHAR,
EXT_BOOL,
EXT_INT,
EXT_TRISTATE,
EXT_CHAR_ARR,
};
struct extern_desc {
const char *name;
int sym_idx;
int btf_id;
enum extern_type type;
int sz;
int align;
int data_off;
bool is_signed;
bool is_weak;
bool is_set;
};
static LIST_HEAD(bpf_objects_list);
struct bpf_object {
char name[BPF_OBJ_NAME_LEN];
char license[64];
__u32 kern_version;
struct bpf_program *programs;
size_t nr_programs;
struct bpf_map *maps;
size_t nr_maps;
size_t maps_cap;
char *kconfig;
struct extern_desc *externs;
int nr_extern;
int kconfig_map_idx;
bool loaded;
bool has_pseudo_calls;
/*
* Information when doing elf related work. Only valid if fd
* is valid.
*/
struct {
int fd;
const void *obj_buf;
size_t obj_buf_sz;
Elf *elf;
GElf_Ehdr ehdr;
Elf_Data *symbols;
Elf_Data *data;
Elf_Data *rodata;
Elf_Data *bss;
Elf_Data *st_ops_data;
size_t strtabidx;
struct {
GElf_Shdr shdr;
Elf_Data *data;
} *reloc_sects;
int nr_reloc_sects;
int maps_shndx;
int btf_maps_shndx;
int text_shndx;
int symbols_shndx;
int data_shndx;
int rodata_shndx;
int bss_shndx;
int st_ops_shndx;
} efile;
/*
* All loaded bpf_object is linked in a list, which is
* hidden to caller. bpf_objects__<func> handlers deal with
* all objects.
*/
struct list_head list;
struct btf *btf;
/* Parse and load BTF vmlinux if any of the programs in the object need
* it at load time.
*/
struct btf *btf_vmlinux;
struct btf_ext *btf_ext;
void *priv;
bpf_object_clear_priv_t clear_priv;
struct bpf_capabilities caps;
char path[];
};
#define obj_elf_valid(o) ((o)->efile.elf)
void bpf_program__unload(struct bpf_program *prog)
{
int i;
if (!prog)
return;
/*
* If the object is opened but the program was never loaded,
* it is possible that prog->instances.nr == -1.
*/
if (prog->instances.nr > 0) {
for (i = 0; i < prog->instances.nr; i++)
zclose(prog->instances.fds[i]);
} else if (prog->instances.nr != -1) {
pr_warn("Internal error: instances.nr is %d\n",
prog->instances.nr);
}
prog->instances.nr = -1;
zfree(&prog->instances.fds);
zfree(&prog->func_info);
zfree(&prog->line_info);
}
static void bpf_program__exit(struct bpf_program *prog)
{
if (!prog)
return;
if (prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = NULL;
prog->clear_priv = NULL;
bpf_program__unload(prog);
zfree(&prog->name);
zfree(&prog->section_name);
zfree(&prog->pin_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
prog->insns_cnt = 0;
prog->idx = -1;
}
static char *__bpf_program__pin_name(struct bpf_program *prog)
{
char *name, *p;
name = p = strdup(prog->section_name);
while ((p = strchr(p, '/')))
*p = '_';
return name;
}
static int
bpf_program__init(void *data, size_t size, char *section_name, int idx,
struct bpf_program *prog)
{
const size_t bpf_insn_sz = sizeof(struct bpf_insn);
if (size == 0 || size % bpf_insn_sz) {
pr_warn("corrupted section '%s', size: %zu\n",
section_name, size);
return -EINVAL;
}
memset(prog, 0, sizeof(*prog));
prog->section_name = strdup(section_name);
if (!prog->section_name) {
pr_warn("failed to alloc name for prog under section(%d) %s\n",
idx, section_name);
goto errout;
}
prog->pin_name = __bpf_program__pin_name(prog);
if (!prog->pin_name) {
pr_warn("failed to alloc pin name for prog under section(%d) %s\n",
idx, section_name);
goto errout;
}
prog->insns = malloc(size);
if (!prog->insns) {
pr_warn("failed to alloc insns for prog under section %s\n",
section_name);
goto errout;
}
prog->insns_cnt = size / bpf_insn_sz;
memcpy(prog->insns, data, size);
prog->idx = idx;
prog->instances.fds = NULL;
prog->instances.nr = -1;
prog->type = BPF_PROG_TYPE_UNSPEC;
return 0;
errout:
bpf_program__exit(prog);
return -ENOMEM;
}
static int
bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
char *section_name, int idx)
{
struct bpf_program prog, *progs;
int nr_progs, err;
err = bpf_program__init(data, size, section_name, idx, &prog);
if (err)
return err;
prog.caps = &obj->caps;
progs = obj->programs;
nr_progs = obj->nr_programs;
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
if (!progs) {
/*
* In this case the original obj->programs
* is still valid, so don't need special treat for
* bpf_close_object().
*/
pr_warn("failed to alloc a new program under section '%s'\n",
section_name);
bpf_program__exit(&prog);
return -ENOMEM;
}
pr_debug("found program %s\n", prog.section_name);
obj->programs = progs;
obj->nr_programs = nr_progs + 1;
prog.obj = obj;
progs[nr_progs] = prog;
return 0;
}
static int
bpf_object__init_prog_names(struct bpf_object *obj)
{
Elf_Data *symbols = obj->efile.symbols;
struct bpf_program *prog;
size_t pi, si;
for (pi = 0; pi < obj->nr_programs; pi++) {
const char *name = NULL;
prog = &obj->programs[pi];
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (sym.st_shndx != prog->idx)
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
continue;
name = elf_strptr(obj->efile.elf,
obj->efile.strtabidx,
sym.st_name);
if (!name) {
pr_warn("failed to get sym name string for prog %s\n",
prog->section_name);
return -LIBBPF_ERRNO__LIBELF;
}
}
if (!name && prog->idx == obj->efile.text_shndx)
name = ".text";
if (!name) {
pr_warn("failed to find sym for prog %s\n",
prog->section_name);
return -EINVAL;
}
prog->name = strdup(name);
if (!prog->name) {
pr_warn("failed to allocate memory for prog sym %s\n",
name);
return -ENOMEM;
}
}
return 0;
}
static __u32 get_kernel_version(void)
{
__u32 major, minor, patch;
struct utsname info;
uname(&info);
if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
return 0;
return KERNEL_VERSION(major, minor, patch);
}
static const struct btf_member *
find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
{
struct btf_member *m;
int i;
for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
if (btf_member_bit_offset(t, i) == bit_offset)
return m;
}
return NULL;
}
static const struct btf_member *
find_member_by_name(const struct btf *btf, const struct btf_type *t,
const char *name)
{
struct btf_member *m;
int i;
for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
return m;
}
return NULL;
}
#define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
const char *name, __u32 kind);
static int
find_struct_ops_kern_types(const struct btf *btf, const char *tname,
const struct btf_type **type, __u32 *type_id,
const struct btf_type **vtype, __u32 *vtype_id,
const struct btf_member **data_member)
{
const struct btf_type *kern_type, *kern_vtype;
const struct btf_member *kern_data_member;
__s32 kern_vtype_id, kern_type_id;
__u32 i;
kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
if (kern_type_id < 0) {
pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n",
tname);
return kern_type_id;
}
kern_type = btf__type_by_id(btf, kern_type_id);
/* Find the corresponding "map_value" type that will be used
* in map_update(BPF_MAP_TYPE_STRUCT_OPS). For example,
* find "struct bpf_struct_ops_tcp_congestion_ops" from the
* btf_vmlinux.
*/
kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX,
tname, BTF_KIND_STRUCT);
if (kern_vtype_id < 0) {
pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n",
STRUCT_OPS_VALUE_PREFIX, tname);
return kern_vtype_id;
}
kern_vtype = btf__type_by_id(btf, kern_vtype_id);
/* Find "struct tcp_congestion_ops" from
* struct bpf_struct_ops_tcp_congestion_ops {
* [ ... ]
* struct tcp_congestion_ops data;
* }
*/
kern_data_member = btf_members(kern_vtype);
for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) {
if (kern_data_member->type == kern_type_id)
break;
}
if (i == btf_vlen(kern_vtype)) {
pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n",
tname, STRUCT_OPS_VALUE_PREFIX, tname);
return -EINVAL;
}
*type = kern_type;
*type_id = kern_type_id;
*vtype = kern_vtype;
*vtype_id = kern_vtype_id;
*data_member = kern_data_member;
return 0;
}
static bool bpf_map__is_struct_ops(const struct bpf_map *map)
{
return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
}
/* Init the map's fields that depend on kern_btf */
static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
const struct btf *btf,
const struct btf *kern_btf)
{
const struct btf_member *member, *kern_member, *kern_data_member;
const struct btf_type *type, *kern_type, *kern_vtype;
__u32 i, kern_type_id, kern_vtype_id, kern_data_off;
struct bpf_struct_ops *st_ops;
void *data, *kern_data;
const char *tname;
int err;
st_ops = map->st_ops;
type = st_ops->type;
tname = st_ops->tname;
err = find_struct_ops_kern_types(kern_btf, tname,
&kern_type, &kern_type_id,
&kern_vtype, &kern_vtype_id,
&kern_data_member);
if (err)
return err;
pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
map->def.value_size = kern_vtype->size;
map->btf_vmlinux_value_type_id = kern_vtype_id;
st_ops->kern_vdata = calloc(1, kern_vtype->size);
if (!st_ops->kern_vdata)
return -ENOMEM;
data = st_ops->data;
kern_data_off = kern_data_member->offset / 8;
kern_data = st_ops->kern_vdata + kern_data_off;
member = btf_members(type);
for (i = 0; i < btf_vlen(type); i++, member++) {
const struct btf_type *mtype, *kern_mtype;
__u32 mtype_id, kern_mtype_id;
void *mdata, *kern_mdata;
__s64 msize, kern_msize;
__u32 moff, kern_moff;
__u32 kern_member_idx;
const char *mname;
mname = btf__name_by_offset(btf, member->name_off);
kern_member = find_member_by_name(kern_btf, kern_type, mname);
if (!kern_member) {
pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
map->name, mname);
return -ENOTSUP;
}
kern_member_idx = kern_member - btf_members(kern_type);
if (btf_member_bitfield_size(type, i) ||
btf_member_bitfield_size(kern_type, kern_member_idx)) {
pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n",
map->name, mname);
return -ENOTSUP;
}
moff = member->offset / 8;
kern_moff = kern_member->offset / 8;
mdata = data + moff;
kern_mdata = kern_data + kern_moff;
mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type,
&kern_mtype_id);
if (BTF_INFO_KIND(mtype->info) !=
BTF_INFO_KIND(kern_mtype->info)) {
pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n",
map->name, mname, BTF_INFO_KIND(mtype->info),
BTF_INFO_KIND(kern_mtype->info));
return -ENOTSUP;
}
if (btf_is_ptr(mtype)) {
struct bpf_program *prog;
mtype = skip_mods_and_typedefs(btf, mtype->type, &mtype_id);
kern_mtype = skip_mods_and_typedefs(kern_btf,
kern_mtype->type,
&kern_mtype_id);
if (!btf_is_func_proto(mtype) ||
!btf_is_func_proto(kern_mtype)) {
pr_warn("struct_ops init_kern %s: non func ptr %s is not supported\n",
map->name, mname);
return -ENOTSUP;
}
prog = st_ops->progs[i];
if (!prog) {
pr_debug("struct_ops init_kern %s: func ptr %s is not set\n",
map->name, mname);
continue;
}
prog->attach_btf_id = kern_type_id;
prog->expected_attach_type = kern_member_idx;
st_ops->kern_func_off[i] = kern_data_off + kern_moff;
pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
map->name, mname, prog->name, moff,
kern_moff);
continue;
}
msize = btf__resolve_size(btf, mtype_id);
kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
map->name, mname, (ssize_t)msize,
(ssize_t)kern_msize);
return -ENOTSUP;
}
pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
map->name, mname, (unsigned int)msize,
moff, kern_moff);
memcpy(kern_mdata, mdata, msize);
}
return 0;
}
static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
{
struct bpf_map *map;
size_t i;
int err;
for (i = 0; i < obj->nr_maps; i++) {
map = &obj->maps[i];
if (!bpf_map__is_struct_ops(map))
continue;
err = bpf_map__init_kern_struct_ops(map, obj->btf,
obj->btf_vmlinux);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_struct_ops_maps(struct bpf_object *obj)
{
const struct btf_type *type, *datasec;
const struct btf_var_secinfo *vsi;
struct bpf_struct_ops *st_ops;
const char *tname, *var_name;
__s32 type_id, datasec_id;
const struct btf *btf;
struct bpf_map *map;
__u32 i;
if (obj->efile.st_ops_shndx == -1)
return 0;
btf = obj->btf;
datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC,
BTF_KIND_DATASEC);
if (datasec_id < 0) {
pr_warn("struct_ops init: DATASEC %s not found\n",
STRUCT_OPS_SEC);
return -EINVAL;
}
datasec = btf__type_by_id(btf, datasec_id);
vsi = btf_var_secinfos(datasec);
for (i = 0; i < btf_vlen(datasec); i++, vsi++) {
type = btf__type_by_id(obj->btf, vsi->type);
var_name = btf__name_by_offset(obj->btf, type->name_off);
type_id = btf__resolve_type(obj->btf, vsi->type);
if (type_id < 0) {
pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
vsi->type, STRUCT_OPS_SEC);
return -EINVAL;
}
type = btf__type_by_id(obj->btf, type_id);
tname = btf__name_by_offset(obj->btf, type->name_off);
if (!tname[0]) {
pr_warn("struct_ops init: anonymous type is not supported\n");
return -ENOTSUP;
}
if (!btf_is_struct(type)) {
pr_warn("struct_ops init: %s is not a struct\n", tname);
return -EINVAL;
}
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->sec_idx = obj->efile.st_ops_shndx;
map->sec_offset = vsi->offset;
map->name = strdup(var_name);
if (!map->name)
return -ENOMEM;
map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
map->def.key_size = sizeof(int);
map->def.value_size = type->size;
map->def.max_entries = 1;
map->st_ops = calloc(1, sizeof(*map->st_ops));
if (!map->st_ops)
return -ENOMEM;
st_ops = map->st_ops;
st_ops->data = malloc(type->size);
st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
st_ops->kern_func_off = malloc(btf_vlen(type) *
sizeof(*st_ops->kern_func_off));
if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
return -ENOMEM;
if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) {
pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n",
var_name, STRUCT_OPS_SEC);
return -EINVAL;
}
memcpy(st_ops->data,
obj->efile.st_ops_data->d_buf + vsi->offset,
type->size);
st_ops->tname = tname;
st_ops->type = type;
st_ops->type_id = type_id;
pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n",
tname, type_id, var_name, vsi->offset);
}
return 0;
}
static struct bpf_object *bpf_object__new(const char *path,
const void *obj_buf,
size_t obj_buf_sz,
const char *obj_name)
{
struct bpf_object *obj;
char *end;
obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
if (!obj) {
pr_warn("alloc memory failed for %s\n", path);
return ERR_PTR(-ENOMEM);
}
strcpy(obj->path, path);
if (obj_name) {
strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
obj->name[sizeof(obj->name) - 1] = 0;
} else {
/* Using basename() GNU version which doesn't modify arg. */
strncpy(obj->name, basename((void *)path),
sizeof(obj->name) - 1);
end = strchr(obj->name, '.');
if (end)
*end = 0;
}
obj->efile.fd = -1;
/*
* Caller of this function should also call
* bpf_object__elf_finish() after data collection to return
* obj_buf to user. If not, we should duplicate the buffer to
* avoid user freeing them before elf finish.
*/
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;
obj->efile.st_ops_shndx = -1;
obj->kconfig_map_idx = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
INIT_LIST_HEAD(&obj->list);
list_add(&obj->list, &bpf_objects_list);
return obj;
}
static void bpf_object__elf_finish(struct bpf_object *obj)
{
if (!obj_elf_valid(obj))
return;
if (obj->efile.elf) {
elf_end(obj->efile.elf);
obj->efile.elf = NULL;
}
obj->efile.symbols = NULL;
obj->efile.data = NULL;
obj->efile.rodata = NULL;
obj->efile.bss = NULL;
obj->efile.st_ops_data = NULL;
zfree(&obj->efile.reloc_sects);
obj->efile.nr_reloc_sects = 0;
zclose(obj->efile.fd);
obj->efile.obj_buf = NULL;
obj->efile.obj_buf_sz = 0;
}
static int bpf_object__elf_init(struct bpf_object *obj)
{
int err = 0;
GElf_Ehdr *ep;
if (obj_elf_valid(obj)) {
pr_warn("elf init: internal error\n");
return -LIBBPF_ERRNO__LIBELF;
}
if (obj->efile.obj_buf_sz > 0) {
/*
* obj_buf should have been validated by
* bpf_object__open_buffer().
*/
obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
obj->efile.obj_buf_sz);
} else {
obj->efile.fd = open(obj->path, O_RDONLY);
if (obj->efile.fd < 0) {
char errmsg[STRERR_BUFSIZE], *cp;
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to open %s: %s\n", obj->path, cp);
return err;
}
obj->efile.elf = elf_begin(obj->efile.fd,
LIBBPF_ELF_C_READ_MMAP, NULL);
}
if (!obj->efile.elf) {
pr_warn("failed to open %s as ELF file\n", obj->path);
err = -LIBBPF_ERRNO__LIBELF;
goto errout;
}
if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
pr_warn("failed to get EHDR from %s\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
ep = &obj->efile.ehdr;
/* Old LLVM set e_machine to EM_NONE */
if (ep->e_type != ET_REL ||
(ep->e_machine && ep->e_machine != EM_BPF)) {
pr_warn("%s is not an eBPF object file\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
return 0;
errout:
bpf_object__elf_finish(obj);
return err;
}
static int bpf_object__check_endianness(struct bpf_object *obj)
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return 0;
#elif __BYTE_ORDER == __BIG_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
return 0;
#else
# error "Unrecognized __BYTE_ORDER__"
#endif
pr_warn("endianness mismatch.\n");
return -LIBBPF_ERRNO__ENDIAN;
}
static int
bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
{
memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
pr_debug("license of %s is %s\n", obj->path, obj->license);
return 0;
}
static int
bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
{
__u32 kver;
if (size != sizeof(kver)) {
pr_warn("invalid kver section in %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
memcpy(&kver, data, sizeof(kver));
obj->kern_version = kver;
pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
return 0;
}
static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
{
if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
type == BPF_MAP_TYPE_HASH_OF_MAPS)
return true;
return false;
}
static int bpf_object_search_section_size(const struct bpf_object *obj,
const char *name, size_t *d_size)
{
const GElf_Ehdr *ep = &obj->efile.ehdr;
Elf *elf = obj->efile.elf;
Elf_Scn *scn = NULL;
int idx = 0;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
const char *sec_name;
Elf_Data *data;
GElf_Shdr sh;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, obj->path);
return -EIO;
}
sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!sec_name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, obj->path);
return -EIO;
}
if (strcmp(name, sec_name))
continue;
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
return -EIO;
}
*d_size = data->d_size;
return 0;
}
return -ENOENT;
}
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size)
{
int ret = -ENOENT;
size_t d_size;
*size = 0;
if (!name) {
return -EINVAL;
} else if (!strcmp(name, DATA_SEC)) {
if (obj->efile.data)
*size = obj->efile.data->d_size;
} else if (!strcmp(name, BSS_SEC)) {
if (obj->efile.bss)
*size = obj->efile.bss->d_size;
} else if (!strcmp(name, RODATA_SEC)) {
if (obj->efile.rodata)
*size = obj->efile.rodata->d_size;
} else if (!strcmp(name, STRUCT_OPS_SEC)) {
if (obj->efile.st_ops_data)
*size = obj->efile.st_ops_data->d_size;
} else {
ret = bpf_object_search_section_size(obj, name, &d_size);
if (!ret)
*size = d_size;
}
return *size ? 0 : ret;
}
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off)
{
Elf_Data *symbols = obj->efile.symbols;
const char *sname;
size_t si;
if (!name || !off)
return -EINVAL;
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
continue;
sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name);
if (!sname) {
pr_warn("failed to get sym name string for var %s\n",
name);
return -EIO;
}
if (strcmp(name, sname) == 0) {
*off = sym.st_value;
return 0;
}
}
return -ENOENT;
}
static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
{
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((size_t)4, obj->maps_cap * 3 / 2);
new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
if (!new_maps) {
pr_warn("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 size_t bpf_map_mmap_sz(const struct bpf_map *map)
{
long page_sz = sysconf(_SC_PAGE_SIZE);
size_t map_sz;
map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
map_sz = roundup(map_sz, page_sz);
return map_sz;
}
static char *internal_map_name(struct bpf_object *obj,
enum libbpf_map_type type)
{
char map_name[BPF_OBJ_NAME_LEN], *p;
const char *sfx = libbpf_type_to_btf_name[type];
int sfx_len = max((size_t)7, strlen(sfx));
int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
strlen(obj->name));
snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
sfx_len, libbpf_type_to_btf_name[type]);
/* sanitise map name to characters allowed by kernel */
for (p = map_name; *p && p < map_name + sizeof(map_name); p++)
if (!isalnum(*p) && *p != '_' && *p != '.')
*p = '_';
return strdup(map_name);
}
static int
bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
int sec_idx, void *data, size_t data_sz)
{
struct bpf_map_def *def;
struct bpf_map *map;
int err;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->libbpf_type = type;
map->sec_idx = sec_idx;
map->sec_offset = 0;
map->name = internal_map_name(obj, type);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
def = &map->def;
def->type = BPF_MAP_TYPE_ARRAY;
def->key_size = sizeof(int);
def->value_size = data_sz;
def->max_entries = 1;
def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
? BPF_F_RDONLY_PROG : 0;
def->map_flags |= BPF_F_MMAPABLE;
pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
map->name, map->sec_idx, map->sec_offset, def->map_flags);
map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (map->mmaped == MAP_FAILED) {
err = -errno;
map->mmaped = NULL;
pr_warn("failed to alloc map '%s' content buffer: %d\n",
map->name, err);
zfree(&map->name);
return err;
}
if (data)
memcpy(map->mmaped, data, data_sz);
pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
return 0;
}
static int bpf_object__init_global_data_maps(struct bpf_object *obj)
{
int err;
/*
* 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_shndx,
obj->efile.data->d_buf,
obj->efile.data->d_size);
if (err)
return err;
}
if (obj->efile.rodata_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
obj->efile.rodata_shndx,
obj->efile.rodata->d_buf,
obj->efile.rodata->d_size);
if (err)
return err;
}
if (obj->efile.bss_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
obj->efile.bss_shndx,
NULL,
obj->efile.bss->d_size);
if (err)
return err;
}
return 0;
}
static struct extern_desc *find_extern_by_name(const struct bpf_object *obj,
const void *name)
{
int i;
for (i = 0; i < obj->nr_extern; i++) {
if (strcmp(obj->externs[i].name, name) == 0)
return &obj->externs[i];
}
return NULL;
}
static int set_ext_value_tri(struct extern_desc *ext, void *ext_val,
char value)
{
switch (ext->type) {
case EXT_BOOL:
if (value == 'm') {
pr_warn("extern %s=%c should be tristate or char\n",
ext->name, value);
return -EINVAL;
}
*(bool *)ext_val = value == 'y' ? true : false;
break;
case EXT_TRISTATE:
if (value == 'y')
*(enum libbpf_tristate *)ext_val = TRI_YES;
else if (value == 'm')
*(enum libbpf_tristate *)ext_val = TRI_MODULE;
else /* value == 'n' */
*(enum libbpf_tristate *)ext_val = TRI_NO;
break;
case EXT_CHAR:
*(char *)ext_val = value;
break;
case EXT_UNKNOWN:
case EXT_INT:
case EXT_CHAR_ARR:
default:
pr_warn("extern %s=%c should be bool, tristate, or char\n",
ext->name, value);
return -EINVAL;
}
ext->is_set = true;
return 0;
}
static int set_ext_value_str(struct extern_desc *ext, char *ext_val,
const char *value)
{
size_t len;
if (ext->type != EXT_CHAR_ARR) {
pr_warn("extern %s=%s should char array\n", ext->name, value);
return -EINVAL;
}
len = strlen(value);
if (value[len - 1] != '"') {
pr_warn("extern '%s': invalid string config '%s'\n",
ext->name, value);
return -EINVAL;
}
/* strip quotes */
len -= 2;
if (len >= ext->sz) {
pr_warn("extern '%s': long string config %s of (%zu bytes) truncated to %d bytes\n",
ext->name, value, len, ext->sz - 1);
len = ext->sz - 1;
}
memcpy(ext_val, value + 1, len);
ext_val[len] = '\0';
ext->is_set = true;
return 0;
}
static int parse_u64(const char *value, __u64 *res)
{
char *value_end;
int err;
errno = 0;
*res = strtoull(value, &value_end, 0);
if (errno) {
err = -errno;
pr_warn("failed to parse '%s' as integer: %d\n", value, err);
return err;
}
if (*value_end) {
pr_warn("failed to parse '%s' as integer completely\n", value);
return -EINVAL;
}
return 0;
}
static bool is_ext_value_in_range(const struct extern_desc *ext, __u64 v)
{
int bit_sz = ext->sz * 8;
if (ext->sz == 8)
return true;
/* Validate that value stored in u64 fits in integer of `ext->sz`
* bytes size without any loss of information. If the target integer
* is signed, we rely on the following limits of integer type of
* Y bits and subsequent transformation:
*
* -2^(Y-1) <= X <= 2^(Y-1) - 1
* 0 <= X + 2^(Y-1) <= 2^Y - 1
* 0 <= X + 2^(Y-1) < 2^Y
*
* For unsigned target integer, check that all the (64 - Y) bits are
* zero.
*/
if (ext->is_signed)
return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz);
else
return (v >> bit_sz) == 0;
}
static int set_ext_value_num(struct extern_desc *ext, void *ext_val,
__u64 value)
{
if (ext->type != EXT_INT && ext->type != EXT_CHAR) {
pr_warn("extern %s=%llu should be integer\n",
ext->name, (unsigned long long)value);
return -EINVAL;
}
if (!is_ext_value_in_range(ext, value)) {
pr_warn("extern %s=%llu value doesn't fit in %d bytes\n",
ext->name, (unsigned long long)value, ext->sz);
return -ERANGE;
}
switch (ext->sz) {
case 1: *(__u8 *)ext_val = value; break;
case 2: *(__u16 *)ext_val = value; break;
case 4: *(__u32 *)ext_val = value; break;
case 8: *(__u64 *)ext_val = value; break;
default:
return -EINVAL;
}
ext->is_set = true;
return 0;
}
static int bpf_object__process_kconfig_line(struct bpf_object *obj,
char *buf, void *data)
{
struct extern_desc *ext;
char *sep, *value;
int len, err = 0;
void *ext_val;
__u64 num;
if (strncmp(buf, "CONFIG_", 7))
return 0;
sep = strchr(buf, '=');
if (!sep) {
pr_warn("failed to parse '%s': no separator\n", buf);
return -EINVAL;
}
/* Trim ending '\n' */
len = strlen(buf);
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
/* Split on '=' and ensure that a value is present. */
*sep = '\0';
if (!sep[1]) {
*sep = '=';
pr_warn("failed to parse '%s': no value\n", buf);
return -EINVAL;
}
ext = find_extern_by_name(obj, buf);
if (!ext || ext->is_set)
return 0;
ext_val = data + ext->data_off;
value = sep + 1;
switch (*value) {
case 'y': case 'n': case 'm':
err = set_ext_value_tri(ext, ext_val, *value);
break;
case '"':
err = set_ext_value_str(ext, ext_val, value);
break;
default:
/* assume integer */
err = parse_u64(value, &num);
if (err) {
pr_warn("extern %s=%s should be integer\n",
ext->name, value);
return err;
}
err = set_ext_value_num(ext, ext_val, num);
break;
}
if (err)
return err;
pr_debug("extern %s=%s\n", ext->name, value);
return 0;
}
static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data)
{
char buf[PATH_MAX];
struct utsname uts;
int len, err = 0;
gzFile file;
uname(&uts);
len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
/* gzopen also accepts uncompressed files. */
file = gzopen(buf, "r");
if (!file)
file = gzopen("/proc/config.gz", "r");
if (!file) {
pr_warn("failed to open system Kconfig\n");
return -ENOENT;
}
while (gzgets(file, buf, sizeof(buf))) {
err = bpf_object__process_kconfig_line(obj, buf, data);
if (err) {
pr_warn("error parsing system Kconfig line '%s': %d\n",
buf, err);
goto out;
}
}
out:
gzclose(file);
return err;
}
static int bpf_object__read_kconfig_mem(struct bpf_object *obj,
const char *config, void *data)
{
char buf[PATH_MAX];
int err = 0;
FILE *file;
file = fmemopen((void *)config, strlen(config), "r");
if (!file) {
err = -errno;
pr_warn("failed to open in-memory Kconfig: %d\n", err);
return err;
}
while (fgets(buf, sizeof(buf), file)) {
err = bpf_object__process_kconfig_line(obj, buf, data);
if (err) {
pr_warn("error parsing in-memory Kconfig line '%s': %d\n",
buf, err);
break;
}
}
fclose(file);
return err;
}
static int bpf_object__init_kconfig_map(struct bpf_object *obj)
{
struct extern_desc *last_ext;
size_t map_sz;
int err;
if (obj->nr_extern == 0)
return 0;
last_ext = &obj->externs[obj->nr_extern - 1];
map_sz = last_ext->data_off + last_ext->sz;
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
obj->efile.symbols_shndx,
NULL, map_sz);
if (err)
return err;
obj->kconfig_map_idx = obj->nr_maps - 1;
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 (!symbols)
return -EINVAL;
scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
if (scn)
data = elf_getdata(scn, NULL);
if (!scn || !data) {
pr_warn("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.
*/
nr_syms = symbols->d_size / sizeof(GElf_Sym);
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
nr_maps++;
}
/* Assume equally sized map definitions */
pr_debug("maps in %s: %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
pr_warn("unable to determine map definition size section %s, %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
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++) {
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 = 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_warn("failed to get map #%d name sym string for obj %s\n",
i, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
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("failed to alloc map name\n");
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));
}
}
return 0;
}
static const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
{
const struct btf_type *t = btf__type_by_id(btf, id);
if (res_id)
*res_id = id;
while (btf_is_mod(t) || btf_is_typedef(t)) {
if (res_id)
*res_id = t->type;
t = btf__type_by_id(btf, t->type);
}
return t;
}
static const struct btf_type *
resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
{
const struct btf_type *t;
t = skip_mods_and_typedefs(btf, id, NULL);
if (!btf_is_ptr(t))
return NULL;
t = skip_mods_and_typedefs(btf, t->type, res_id);
return btf_is_func_proto(t) ? t : NULL;
}
/*
* Fetch integer attribute of BTF map definition. Such attributes are
* represented using a pointer to an array, in which dimensionality of array
* encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
* encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
* type definition, while using only sizeof(void *) space in ELF data section.
*/
static bool get_map_field_int(const char *map_name, const struct btf *btf,
const struct btf_type *def,
const struct btf_member *m, __u32 *res)
{
const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
const char *name = btf__name_by_offset(btf, m->name_off);
const struct btf_array *arr_info;
const struct btf_type *arr_t;
if (!btf_is_ptr(t)) {
pr_warn("map '%s': attr '%s': expected PTR, got %u.\n",
map_name, name, btf_kind(t));
return false;
}
arr_t = btf__type_by_id(btf, t->type);
if (!arr_t) {
pr_warn("map '%s': attr '%s': type [%u] not found.\n",
map_name, name, t->type);
return false;
}
if (!btf_is_array(arr_t)) {
pr_warn("map '%s': attr '%s': expected ARRAY, got %u.\n",
map_name, name, btf_kind(arr_t));
return false;
}
arr_info = btf_array(arr_t);
*res = arr_info->nelems;
return true;
}
static int build_map_pin_path(struct bpf_map *map, const char *path)
{
char buf[PATH_MAX];
int err, len;
if (!path)
path = "/sys/fs/bpf";
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__set_pin_path(map, buf);
if (err)
return err;
return 0;
}
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 char *pin_root_path)
{
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 char *map_name;
struct bpf_map *map;
int vlen, i;
vi = btf_var_secinfos(sec) + var_idx;
var = btf__type_by_id(obj->btf, vi->type);
var_extra = btf_var(var);
map_name = btf__name_by_offset(obj->btf, var->name_off);
vlen = btf_vlen(var);
if (map_name == NULL || map_name[0] == '\0') {
pr_warn("map #%d: empty name.\n", var_idx);
return -EINVAL;
}
if ((__u64)vi->offset + vi->size > data->d_size) {
pr_warn("map '%s' BTF data is corrupted.\n", map_name);
return -EINVAL;
}
if (!btf_is_var(var)) {
pr_warn("map '%s': unexpected var kind %u.\n",
map_name, btf_kind(var));
return -EINVAL;
}
if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
var_extra->linkage != BTF_VAR_STATIC) {
pr_warn("map '%s': unsupported var linkage %u.\n",
map_name, var_extra->linkage);
return -EOPNOTSUPP;
}
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (!btf_is_struct(def)) {
pr_warn("map '%s': unexpected def kind %u.\n",
map_name, btf_kind(var));
return -EINVAL;
}
if (def->size > vi->size) {
pr_warn("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_warn("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);
vlen = btf_vlen(def);
m = btf_members(def);
for (i = 0; i < vlen; i++, m++) {
const char *name = btf__name_by_offset(obj->btf, m->name_off);
if (!name) {
pr_warn("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,
&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,
&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,
&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,
&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_warn("map '%s': conflicting 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_warn("map '%s': key type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': key spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
map_name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found key [%u], sz = %zd.\n",
map_name, t->type, (ssize_t)sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %zd.\n",
map_name, map->def.key_size, (ssize_t)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,
&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_warn("map '%s': conflicting 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_warn("map '%s': value type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': value spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
map_name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found value [%u], sz = %zd.\n",
map_name, t->type, (ssize_t)sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %zd.\n",
map_name, map->def.value_size, (ssize_t)sz);
return -EINVAL;
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
} else if (strcmp(name, "pinning") == 0) {
__u32 val;
int err;
if (!get_map_field_int(map_name, obj->btf, def, m,
&val))
return -EINVAL;
pr_debug("map '%s': found pinning = %u.\n",
map_name, val);
if (val != LIBBPF_PIN_NONE &&
val != LIBBPF_PIN_BY_NAME) {
pr_warn("map '%s': invalid pinning value %u.\n",
map_name, val);
return -EINVAL;
}
if (val == LIBBPF_PIN_BY_NAME) {
err = build_map_pin_path(map, pin_root_path);
if (err) {
pr_warn("map '%s': couldn't build pin path.\n",
map_name);
return err;
}
}
} else {
if (strict) {
pr_warn("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_warn("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 char *pin_root_path)
{
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_warn("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_is_datasec(t))
continue;
name = btf__name_by_offset(obj->btf, t->name_off);
if (strcmp(name, MAPS_ELF_SEC) == 0) {
sec = t;
break;
}
}
if (!sec) {
pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
return -ENOENT;
}
vlen = btf_vlen(sec);
for (i = 0; i < vlen; i++) {
err = bpf_object__init_user_btf_map(obj, sec, i,
obj->efile.btf_maps_shndx,
data, strict,
pin_root_path);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_maps(struct bpf_object *obj,
const struct bpf_object_open_opts *opts)
{
const char *pin_root_path;
bool strict;
int err;
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);
err = err ?: bpf_object__init_struct_ops_maps(obj);
if (err)
return err;
return 0;
}
static bool section_have_execinstr(struct bpf_object *obj, int idx)
{
Elf_Scn *scn;
GElf_Shdr sh;
scn = elf_getscn(obj->efile.elf, idx);
if (!scn)
return false;
if (gelf_getshdr(scn, &sh) != &sh)
return false;
if (sh.sh_flags & SHF_EXECINSTR)
return true;
return false;
}
static void bpf_object__sanitize_btf(struct bpf_object *obj)
{
bool has_func_global = obj->caps.btf_func_global;
bool has_datasec = obj->caps.btf_datasec;
bool has_func = obj->caps.btf_func;
struct btf *btf = obj->btf;
struct btf_type *t;
int i, j, vlen;
if (!obj->btf || (has_func && has_datasec && has_func_global))
return;
for (i = 1; i <= btf__get_nr_types(btf); i++) {
t = (struct btf_type *)btf__type_by_id(btf, i);
if (!has_datasec && btf_is_var(t)) {
/* replace VAR with INT */
t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
/*
* using size = 1 is the safest choice, 4 will be too
* big and cause kernel BTF validation failure if
* original variable took less than 4 bytes
*/
t->size = 1;
*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
} else if (!has_datasec && btf_is_datasec(t)) {
/* replace DATASEC with STRUCT */
const struct btf_var_secinfo *v = btf_var_secinfos(t);
struct btf_member *m = btf_members(t);
struct btf_type *vt;
char *name;
name = (char *)btf__name_by_offset(btf, t->name_off);
while (*name) {
if (*name == '.')
*name = '_';
name++;
}
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
for (j = 0; j < vlen; j++, v++, m++) {
/* order of field assignments is important */
m->offset = v->offset * 8;
m->type = v->type;
/* preserve variable name as member name */
vt = (void *)btf__type_by_id(btf, v->type);
m->name_off = vt->name_off;
}
} else if (!has_func && btf_is_func_proto(t)) {
/* replace FUNC_PROTO with ENUM */
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
t->size = sizeof(__u32); /* kernel enforced */
} else if (!has_func && btf_is_func(t)) {
/* replace FUNC with TYPEDEF */
t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
} else if (!has_func_global && btf_is_func(t)) {
/* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
}
}
}
static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
{
if (!obj->btf_ext)
return;
if (!obj->caps.btf_func) {
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
}
}
static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
{
return obj->efile.btf_maps_shndx >= 0 ||
obj->efile.st_ops_shndx >= 0 ||
obj->nr_extern > 0;
}
static int bpf_object__init_btf(struct bpf_object *obj,
Elf_Data *btf_data,
Elf_Data *btf_ext_data)
{
int err = -ENOENT;
if (btf_data) {
obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
if (IS_ERR(obj->btf)) {
err = PTR_ERR(obj->btf);
obj->btf = NULL;
pr_warn("Error loading ELF section %s: %d.\n",
BTF_ELF_SEC, err);
goto out;
}
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);
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_warn("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;
}
}
out:
if (err && bpf_object__is_btf_mandatory(obj)) {
pr_warn("BTF is required, but is missing or corrupted.\n");
return err;
}
return 0;
}
static int bpf_object__finalize_btf(struct bpf_object *obj)
{
int err;
if (!obj->btf)
return 0;
err = btf__finalize_data(obj, obj->btf);
if (!err)
return 0;
pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
btf__free(obj->btf);
obj->btf = NULL;
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
if (bpf_object__is_btf_mandatory(obj)) {
pr_warn("BTF is required, but is missing or corrupted.\n");
return -ENOENT;
}
return 0;
}
static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
{
if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
return true;
/* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
* also need vmlinux BTF
*/
if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
return true;
return false;
}
static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
{
struct bpf_program *prog;
int err;
bpf_object__for_each_program(prog, obj) {
if (libbpf_prog_needs_vmlinux_btf(prog)) {
obj->btf_vmlinux = libbpf_find_kernel_btf();
if (IS_ERR(obj->btf_vmlinux)) {
err = PTR_ERR(obj->btf_vmlinux);
pr_warn("Error loading vmlinux BTF: %d\n", err);
obj->btf_vmlinux = NULL;
return err;
}
return 0;
}
}
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_warn("Error loading %s into kernel: %d.\n",
BTF_ELF_SEC, err);
btf__free(obj->btf);
obj->btf = NULL;
/* btf_ext can't exist without btf, so free it as well */
if (obj->btf_ext) {
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
}
if (bpf_object__is_btf_mandatory(obj))
return err;
}
return 0;
}
static int bpf_object__elf_collect(struct bpf_object *obj)
{
Elf *elf = obj->efile.elf;
GElf_Ehdr *ep = &obj->efile.ehdr;
Elf_Data *btf_ext_data = NULL;
Elf_Data *btf_data = NULL;
Elf_Scn *scn = NULL;
int idx = 0, err = 0;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
pr_warn("failed to get e_shstrndx from %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
while ((scn = elf_nextscn(elf, scn)) != NULL) {
char *name;
GElf_Shdr sh;
Elf_Data *data;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
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,
(int)sh.sh_link, (unsigned long)sh.sh_flags,
(int)sh.sh_type);
if (strcmp(name, "license") == 0) {
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, 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) {
btf_ext_data = data;
} else if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warn("bpf: multiple SYMTAB in %s\n",
obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
obj->efile.symbols = data;
obj->efile.symbols_shndx = idx;
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)
obj->efile.text_shndx = idx;
err = bpf_object__add_program(obj, data->d_buf,
data->d_size,
name, idx);
if (err) {
char errmsg[STRERR_BUFSIZE];
char *cp;
cp = libbpf_strerror_r(-err, errmsg,
sizeof(errmsg));
pr_warn("failed to alloc program %s (%s): %s",
name, obj->path, cp);
return err;
}
} else if (strcmp(name, DATA_SEC) == 0) {
obj->efile.data = data;
obj->efile.data_shndx = idx;
} else if (strcmp(name, RODATA_SEC) == 0) {
obj->efile.rodata = data;
obj->efile.rodata_shndx = idx;
} else if (strcmp(name, STRUCT_OPS_SEC) == 0) {
obj->efile.st_ops_data = data;
obj->efile.st_ops_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
} else if (sh.sh_type == SHT_REL) {
int nr_sects = obj->efile.nr_reloc_sects;
void *sects = obj->efile.reloc_sects;
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
if (!section_have_execinstr(obj, sec) &&
strcmp(name, ".rel" STRUCT_OPS_SEC)) {
pr_debug("skip relo %s(%d) for section(%d)\n",
name, idx, sec);
continue;
}
sects = reallocarray(sects, nr_sects + 1,
sizeof(*obj->efile.reloc_sects));
if (!sects) {
pr_warn("reloc_sects realloc failed\n");
return -ENOMEM;
}
obj->efile.reloc_sects = sects;
obj->efile.nr_reloc_sects++;
obj->efile.reloc_sects[nr_sects].shdr = sh;
obj->efile.reloc_sects[nr_sects].data = data;
} else if (sh.sh_type == SHT_NOBITS &&
strcmp(name, BSS_SEC) == 0) {
obj->efile.bss = data;
obj->efile.bss_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
}
if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
pr_warn("Corrupted ELF file: index of strtab invalid\n");
return -LIBBPF_ERRNO__FORMAT;
}
return bpf_object__init_btf(obj, btf_data, btf_ext_data);
}
static bool sym_is_extern(const GElf_Sym *sym)
{
int bind = GELF_ST_BIND(sym->st_info);
/* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */
return sym->st_shndx == SHN_UNDEF &&
(bind == STB_GLOBAL || bind == STB_WEAK) &&
GELF_ST_TYPE(sym->st_info) == STT_NOTYPE;
}
static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
{
const struct btf_type *t;
const char *var_name;
int i, n;
if (!btf)
return -ESRCH;
n = btf__get_nr_types(btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(btf, i);
if (!btf_is_var(t))
continue;
var_name = btf__name_by_offset(btf, t->name_off);
if (strcmp(var_name, ext_name))
continue;
if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
return -EINVAL;
return i;
}
return -ENOENT;
}
static enum extern_type find_extern_type(const struct btf *btf, int id,
bool *is_signed)
{
const struct btf_type *t;
const char *name;
t = skip_mods_and_typedefs(btf, id, NULL);
name = btf__name_by_offset(btf, t->name_off);
if (is_signed)
*is_signed = false;
switch (btf_kind(t)) {
case BTF_KIND_INT: {
int enc = btf_int_encoding(t);
if (enc & BTF_INT_BOOL)
return t->size == 1 ? EXT_BOOL : EXT_UNKNOWN;
if (is_signed)
*is_signed = enc & BTF_INT_SIGNED;
if (t->size == 1)
return EXT_CHAR;
if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1)))
return EXT_UNKNOWN;
return EXT_INT;
}
case BTF_KIND_ENUM:
if (t->size != 4)
return EXT_UNKNOWN;
if (strcmp(name, "libbpf_tristate"))
return EXT_UNKNOWN;
return EXT_TRISTATE;
case BTF_KIND_ARRAY:
if (btf_array(t)->nelems == 0)
return EXT_UNKNOWN;
if (find_extern_type(btf, btf_array(t)->type, NULL) != EXT_CHAR)
return EXT_UNKNOWN;
return EXT_CHAR_ARR;
default:
return EXT_UNKNOWN;
}
}
static int cmp_externs(const void *_a, const void *_b)
{
const struct extern_desc *a = _a;
const struct extern_desc *b = _b;
/* descending order by alignment requirements */
if (a->align != b->align)