blob: ca080a129b335e140988a569cff3211037dfcaba [file] [log] [blame]
/*
* 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.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <asm/unistd.h>
#include <linux/kernel.h>
#include <linux/bpf.h>
#include <linux/list.h>
#include <libelf.h>
#include <gelf.h>
#include "libbpf.h"
#include "bpf.h"
#define __printf(a, b) __attribute__((format(printf, a, b)))
__printf(1, 2)
static int __base_pr(const char *format, ...)
{
va_list args;
int err;
va_start(args, format);
err = vfprintf(stderr, format, args);
va_end(args);
return err;
}
static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
static __printf(1, 2) libbpf_print_fn_t __pr_debug;
#define __pr(func, fmt, ...) \
do { \
if ((func)) \
(func)("libbpf: " fmt, ##__VA_ARGS__); \
} while (0)
#define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
#define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
#define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)
void libbpf_set_print(libbpf_print_fn_t warn,
libbpf_print_fn_t info,
libbpf_print_fn_t debug)
{
__pr_warning = warn;
__pr_info = info;
__pr_debug = debug;
}
#define STRERR_BUFSIZE 128
#define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
#define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
#define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
static const char *libbpf_strerror_table[NR_ERRNO] = {
[ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
[ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
[ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
[ERRCODE_OFFSET(ENDIAN)] = "Endian missmatch",
[ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
[ERRCODE_OFFSET(RELOC)] = "Relocation failed",
[ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
[ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
[ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
};
int libbpf_strerror(int err, char *buf, size_t size)
{
if (!buf || !size)
return -1;
err = err > 0 ? err : -err;
if (err < __LIBBPF_ERRNO__START) {
int ret;
ret = strerror_r(err, buf, size);
buf[size - 1] = '\0';
return ret;
}
if (err < __LIBBPF_ERRNO__END) {
const char *msg;
msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
snprintf(buf, size, "%s", msg);
buf[size - 1] = '\0';
return 0;
}
snprintf(buf, size, "Unknown libbpf error %d", err);
buf[size - 1] = '\0';
return -1;
}
#define CHECK_ERR(action, err, out) do { \
err = action; \
if (err) \
goto out; \
} while(0)
/* 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
/*
* 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 *section_name;
struct bpf_insn *insns;
size_t insns_cnt;
struct {
int insn_idx;
int map_idx;
} *reloc_desc;
int nr_reloc;
int fd;
struct bpf_object *obj;
void *priv;
bpf_program_clear_priv_t clear_priv;
};
static LIST_HEAD(bpf_objects_list);
struct bpf_object {
char license[64];
u32 kern_version;
void *maps_buf;
size_t maps_buf_sz;
struct bpf_program *programs;
size_t nr_programs;
int *map_fds;
/*
* This field is required because maps_buf will be freed and
* maps_buf_sz will be set to 0 after loaded.
*/
size_t nr_map_fds;
bool loaded;
/*
* Information when doing elf related work. Only valid if fd
* is valid.
*/
struct {
int fd;
void *obj_buf;
size_t obj_buf_sz;
Elf *elf;
GElf_Ehdr ehdr;
Elf_Data *symbols;
struct {
GElf_Shdr shdr;
Elf_Data *data;
} *reloc;
int nr_reloc;
} 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;
char path[];
};
#define obj_elf_valid(o) ((o)->efile.elf)
static void bpf_program__unload(struct bpf_program *prog)
{
if (!prog)
return;
zclose(prog->fd);
}
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->section_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
prog->insns_cnt = 0;
prog->idx = -1;
}
static int
bpf_program__init(void *data, size_t size, char *name, int idx,
struct bpf_program *prog)
{
if (size < sizeof(struct bpf_insn)) {
pr_warning("corrupted section '%s'\n", name);
return -EINVAL;
}
bzero(prog, sizeof(*prog));
prog->section_name = strdup(name);
if (!prog->section_name) {
pr_warning("failed to alloc name for prog %s\n",
name);
goto errout;
}
prog->insns = malloc(size);
if (!prog->insns) {
pr_warning("failed to alloc insns for %s\n", name);
goto errout;
}
prog->insns_cnt = size / sizeof(struct bpf_insn);
memcpy(prog->insns, data,
prog->insns_cnt * sizeof(struct bpf_insn));
prog->idx = idx;
prog->fd = -1;
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 *name, int idx)
{
struct bpf_program prog, *progs;
int nr_progs, err;
err = bpf_program__init(data, size, name, idx, &prog);
if (err)
return err;
progs = obj->programs;
nr_progs = obj->nr_programs;
progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
if (!progs) {
/*
* In this case the original obj->programs
* is still valid, so don't need special treat for
* bpf_close_object().
*/
pr_warning("failed to alloc a new program '%s'\n",
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 struct bpf_object *bpf_object__new(const char *path,
void *obj_buf,
size_t obj_buf_sz)
{
struct bpf_object *obj;
obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
if (!obj) {
pr_warning("alloc memory failed for %s\n", path);
return ERR_PTR(-ENOMEM);
}
strcpy(obj->path, path);
obj->efile.fd = -1;
/*
* Caller of this function should also calls
* 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->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;
zfree(&obj->efile.reloc);
obj->efile.nr_reloc = 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_warning("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(obj->efile.obj_buf,
obj->efile.obj_buf_sz);
} else {
obj->efile.fd = open(obj->path, O_RDONLY);
if (obj->efile.fd < 0) {
pr_warning("failed to open %s: %s\n", obj->path,
strerror(errno));
return -errno;
}
obj->efile.elf = elf_begin(obj->efile.fd,
LIBBPF_ELF_C_READ_MMAP,
NULL);
}
if (!obj->efile.elf) {
pr_warning("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_warning("failed to get EHDR from %s\n",
obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
ep = &obj->efile.ehdr;
if ((ep->e_type != ET_REL) || (ep->e_machine != 0)) {
pr_warning("%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)
{
static unsigned int const endian = 1;
switch (obj->efile.ehdr.e_ident[EI_DATA]) {
case ELFDATA2LSB:
/* We are big endian, BPF obj is little endian. */
if (*(unsigned char const *)&endian != 1)
goto mismatch;
break;
case ELFDATA2MSB:
/* We are little endian, BPF obj is big endian. */
if (*(unsigned char const *)&endian != 0)
goto mismatch;
break;
default:
return -LIBBPF_ERRNO__ENDIAN;
}
return 0;
mismatch:
pr_warning("Error: 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_warning("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 int
bpf_object__init_maps(struct bpf_object *obj, void *data,
size_t size)
{
if (size == 0) {
pr_debug("%s doesn't need map definition\n",
obj->path);
return 0;
}
obj->maps_buf = malloc(size);
if (!obj->maps_buf) {
pr_warning("malloc maps failed: %s\n", obj->path);
return -ENOMEM;
}
obj->maps_buf_sz = size;
memcpy(obj->maps_buf, data, size);
pr_debug("maps in %s: %ld bytes\n", obj->path, (long)size);
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 int bpf_object__elf_collect(struct bpf_object *obj)
{
Elf *elf = obj->efile.elf;
GElf_Ehdr *ep = &obj->efile.ehdr;
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_warning("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_warning("failed to get section header from %s\n",
obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto out;
}
name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!name) {
pr_warning("failed to get section name from %s\n",
obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto out;
}
data = elf_getdata(scn, 0);
if (!data) {
pr_warning("failed to get section data from %s(%s)\n",
name, obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto out;
}
pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
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);
else if (strcmp(name, "version") == 0)
err = bpf_object__init_kversion(obj,
data->d_buf,
data->d_size);
else if (strcmp(name, "maps") == 0)
err = bpf_object__init_maps(obj, data->d_buf,
data->d_size);
else if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warning("bpf: multiple SYMTAB in %s\n",
obj->path);
err = -LIBBPF_ERRNO__FORMAT;
} else
obj->efile.symbols = data;
} else if ((sh.sh_type == SHT_PROGBITS) &&
(sh.sh_flags & SHF_EXECINSTR) &&
(data->d_size > 0)) {
err = bpf_object__add_program(obj, data->d_buf,
data->d_size, name, idx);
if (err) {
char errmsg[STRERR_BUFSIZE];
strerror_r(-err, errmsg, sizeof(errmsg));
pr_warning("failed to alloc program %s (%s): %s",
name, obj->path, errmsg);
}
} else if (sh.sh_type == SHT_REL) {
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 */
if (!section_have_execinstr(obj, sec)) {
pr_debug("skip relo %s(%d) for section(%d)\n",
name, idx, sec);
continue;
}
reloc = realloc(reloc,
sizeof(*obj->efile.reloc) * nr_reloc);
if (!reloc) {
pr_warning("realloc failed\n");
err = -ENOMEM;
} else {
int n = nr_reloc - 1;
obj->efile.reloc = reloc;
obj->efile.nr_reloc = nr_reloc;
obj->efile.reloc[n].shdr = sh;
obj->efile.reloc[n].data = data;
}
}
if (err)
goto out;
}
out:
return err;
}
static struct bpf_program *
bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
{
struct bpf_program *prog;
size_t i;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
if (prog->idx == idx)
return prog;
}
return NULL;
}
static int
bpf_program__collect_reloc(struct bpf_program *prog,
size_t nr_maps, GElf_Shdr *shdr,
Elf_Data *data, Elf_Data *symbols)
{
int i, nrels;
pr_debug("collecting relocating info for: '%s'\n",
prog->section_name);
nrels = shdr->sh_size / shdr->sh_entsize;
prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
if (!prog->reloc_desc) {
pr_warning("failed to alloc memory in relocation\n");
return -ENOMEM;
}
prog->nr_reloc = nrels;
for (i = 0; i < nrels; i++) {
GElf_Sym sym;
GElf_Rel rel;
unsigned int insn_idx;
struct bpf_insn *insns = prog->insns;
size_t map_idx;
if (!gelf_getrel(data, i, &rel)) {
pr_warning("relocation: failed to get %d reloc\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
insn_idx = rel.r_offset / sizeof(struct bpf_insn);
pr_debug("relocation: insn_idx=%u\n", insn_idx);
if (!gelf_getsym(symbols,
GELF_R_SYM(rel.r_info),
&sym)) {
pr_warning("relocation: symbol %"PRIx64" not found\n",
GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
insn_idx, insns[insn_idx].code);
return -LIBBPF_ERRNO__RELOC;
}
map_idx = sym.st_value / sizeof(struct bpf_map_def);
if (map_idx >= nr_maps) {
pr_warning("bpf relocation: map_idx %d large than %d\n",
(int)map_idx, (int)nr_maps - 1);
return -LIBBPF_ERRNO__RELOC;
}
prog->reloc_desc[i].insn_idx = insn_idx;
prog->reloc_desc[i].map_idx = map_idx;
}
return 0;
}
static int
bpf_object__create_maps(struct bpf_object *obj)
{
unsigned int i;
size_t nr_maps;
int *pfd;
nr_maps = obj->maps_buf_sz / sizeof(struct bpf_map_def);
if (!obj->maps_buf || !nr_maps) {
pr_debug("don't need create maps for %s\n",
obj->path);
return 0;
}
obj->map_fds = malloc(sizeof(int) * nr_maps);
if (!obj->map_fds) {
pr_warning("realloc perf_bpf_map_fds failed\n");
return -ENOMEM;
}
obj->nr_map_fds = nr_maps;
/* fill all fd with -1 */
memset(obj->map_fds, -1, sizeof(int) * nr_maps);
pfd = obj->map_fds;
for (i = 0; i < nr_maps; i++) {
struct bpf_map_def def;
def = *(struct bpf_map_def *)(obj->maps_buf +
i * sizeof(struct bpf_map_def));
*pfd = bpf_create_map(def.type,
def.key_size,
def.value_size,
def.max_entries);
if (*pfd < 0) {
size_t j;
int err = *pfd;
pr_warning("failed to create map: %s\n",
strerror(errno));
for (j = 0; j < i; j++)
zclose(obj->map_fds[j]);
obj->nr_map_fds = 0;
zfree(&obj->map_fds);
return err;
}
pr_debug("create map: fd=%d\n", *pfd);
pfd++;
}
zfree(&obj->maps_buf);
obj->maps_buf_sz = 0;
return 0;
}
static int
bpf_program__relocate(struct bpf_program *prog, int *map_fds)
{
int i;
if (!prog || !prog->reloc_desc)
return 0;
for (i = 0; i < prog->nr_reloc; i++) {
int insn_idx, map_idx;
struct bpf_insn *insns = prog->insns;
insn_idx = prog->reloc_desc[i].insn_idx;
map_idx = prog->reloc_desc[i].map_idx;
if (insn_idx >= (int)prog->insns_cnt) {
pr_warning("relocation out of range: '%s'\n",
prog->section_name);
return -LIBBPF_ERRNO__RELOC;
}
insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
insns[insn_idx].imm = map_fds[map_idx];
}
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
return 0;
}
static int
bpf_object__relocate(struct bpf_object *obj)
{
struct bpf_program *prog;
size_t i;
int err;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
err = bpf_program__relocate(prog, obj->map_fds);
if (err) {
pr_warning("failed to relocate '%s'\n",
prog->section_name);
return err;
}
}
return 0;
}
static int bpf_object__collect_reloc(struct bpf_object *obj)
{
int i, err;
if (!obj_elf_valid(obj)) {
pr_warning("Internal error: elf object is closed\n");
return -LIBBPF_ERRNO__INTERNAL;
}
for (i = 0; i < obj->efile.nr_reloc; i++) {
GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
Elf_Data *data = obj->efile.reloc[i].data;
int idx = shdr->sh_info;
struct bpf_program *prog;
size_t nr_maps = obj->maps_buf_sz /
sizeof(struct bpf_map_def);
if (shdr->sh_type != SHT_REL) {
pr_warning("internal error at %d\n", __LINE__);
return -LIBBPF_ERRNO__INTERNAL;
}
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
pr_warning("relocation failed: no %d section\n",
idx);
return -LIBBPF_ERRNO__RELOC;
}
err = bpf_program__collect_reloc(prog, nr_maps,
shdr, data,
obj->efile.symbols);
if (err)
return err;
}
return 0;
}
static int
load_program(struct bpf_insn *insns, int insns_cnt,
char *license, u32 kern_version, int *pfd)
{
int ret;
char *log_buf;
if (!insns || !insns_cnt)
return -EINVAL;
log_buf = malloc(BPF_LOG_BUF_SIZE);
if (!log_buf)
pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
insns_cnt, license, kern_version,
log_buf, BPF_LOG_BUF_SIZE);
if (ret >= 0) {
*pfd = ret;
ret = 0;
goto out;
}
ret = -LIBBPF_ERRNO__LOAD;
pr_warning("load bpf program failed: %s\n", strerror(errno));
if (log_buf && log_buf[0] != '\0') {
ret = -LIBBPF_ERRNO__VERIFY;
pr_warning("-- BEGIN DUMP LOG ---\n");
pr_warning("\n%s\n", log_buf);
pr_warning("-- END LOG --\n");
} else {
if (insns_cnt >= BPF_MAXINSNS) {
pr_warning("Program too large (%d insns), at most %d insns\n",
insns_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
} else if (log_buf) {
pr_warning("log buffer is empty\n");
ret = -LIBBPF_ERRNO__KVER;
}
}
out:
free(log_buf);
return ret;
}
static int
bpf_program__load(struct bpf_program *prog,
char *license, u32 kern_version)
{
int err, fd;
err = load_program(prog->insns, prog->insns_cnt,
license, kern_version, &fd);
if (!err)
prog->fd = fd;
if (err)
pr_warning("failed to load program '%s'\n",
prog->section_name);
zfree(&prog->insns);
prog->insns_cnt = 0;
return err;
}
static int
bpf_object__load_progs(struct bpf_object *obj)
{
size_t i;
int err;
for (i = 0; i < obj->nr_programs; i++) {
err = bpf_program__load(&obj->programs[i],
obj->license,
obj->kern_version);
if (err)
return err;
}
return 0;
}
static int bpf_object__validate(struct bpf_object *obj)
{
if (obj->kern_version == 0) {
pr_warning("%s doesn't provide kernel version\n",
obj->path);
return -LIBBPF_ERRNO__KVERSION;
}
return 0;
}
static struct bpf_object *
__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
{
struct bpf_object *obj;
int err;
if (elf_version(EV_CURRENT) == EV_NONE) {
pr_warning("failed to init libelf for %s\n", path);
return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
}
obj = bpf_object__new(path, obj_buf, obj_buf_sz);
if (IS_ERR(obj))
return obj;
CHECK_ERR(bpf_object__elf_init(obj), err, out);
CHECK_ERR(bpf_object__check_endianness(obj), err, out);
CHECK_ERR(bpf_object__elf_collect(obj), err, out);
CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
CHECK_ERR(bpf_object__validate(obj), err, out);
bpf_object__elf_finish(obj);
return obj;
out:
bpf_object__close(obj);
return ERR_PTR(err);
}
struct bpf_object *bpf_object__open(const char *path)
{
/* param validation */
if (!path)
return NULL;
pr_debug("loading %s\n", path);
return __bpf_object__open(path, NULL, 0);
}
struct bpf_object *bpf_object__open_buffer(void *obj_buf,
size_t obj_buf_sz,
const char *name)
{
char tmp_name[64];
/* param validation */
if (!obj_buf || obj_buf_sz <= 0)
return NULL;
if (!name) {
snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
(unsigned long)obj_buf,
(unsigned long)obj_buf_sz);
tmp_name[sizeof(tmp_name) - 1] = '\0';
name = tmp_name;
}
pr_debug("loading object '%s' from buffer\n",
name);
return __bpf_object__open(name, obj_buf, obj_buf_sz);
}
int bpf_object__unload(struct bpf_object *obj)
{
size_t i;
if (!obj)
return -EINVAL;
for (i = 0; i < obj->nr_map_fds; i++)
zclose(obj->map_fds[i]);
zfree(&obj->map_fds);
obj->nr_map_fds = 0;
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
return 0;
}
int bpf_object__load(struct bpf_object *obj)
{
int err;
if (!obj)
return -EINVAL;
if (obj->loaded) {
pr_warning("object should not be loaded twice\n");
return -EINVAL;
}
obj->loaded = true;
CHECK_ERR(bpf_object__create_maps(obj), err, out);
CHECK_ERR(bpf_object__relocate(obj), err, out);
CHECK_ERR(bpf_object__load_progs(obj), err, out);
return 0;
out:
bpf_object__unload(obj);
pr_warning("failed to load object '%s'\n", obj->path);
return err;
}
void bpf_object__close(struct bpf_object *obj)
{
size_t i;
if (!obj)
return;
bpf_object__elf_finish(obj);
bpf_object__unload(obj);
zfree(&obj->maps_buf);
if (obj->programs && obj->nr_programs) {
for (i = 0; i < obj->nr_programs; i++)
bpf_program__exit(&obj->programs[i]);
}
zfree(&obj->programs);
list_del(&obj->list);
free(obj);
}
struct bpf_object *
bpf_object__next(struct bpf_object *prev)
{
struct bpf_object *next;
if (!prev)
next = list_first_entry(&bpf_objects_list,
struct bpf_object,
list);
else
next = list_next_entry(prev, list);
/* Empty list is noticed here so don't need checking on entry. */
if (&next->list == &bpf_objects_list)
return NULL;
return next;
}
const char *
bpf_object__get_name(struct bpf_object *obj)
{
if (!obj)
return ERR_PTR(-EINVAL);
return obj->path;
}
unsigned int
bpf_object__get_kversion(struct bpf_object *obj)
{
if (!obj)
return 0;
return obj->kern_version;
}
struct bpf_program *
bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
{
size_t idx;
if (!obj->programs)
return NULL;
/* First handler */
if (prev == NULL)
return &obj->programs[0];
if (prev->obj != obj) {
pr_warning("error: program handler doesn't match object\n");
return NULL;
}
idx = (prev - obj->programs) + 1;
if (idx >= obj->nr_programs)
return NULL;
return &obj->programs[idx];
}
int bpf_program__set_private(struct bpf_program *prog,
void *priv,
bpf_program_clear_priv_t clear_priv)
{
if (prog->priv && prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = priv;
prog->clear_priv = clear_priv;
return 0;
}
int bpf_program__get_private(struct bpf_program *prog, void **ppriv)
{
*ppriv = prog->priv;
return 0;
}
const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
{
const char *title;
title = prog->section_name;
if (needs_copy) {
title = strdup(title);
if (!title) {
pr_warning("failed to strdup program title\n");
return ERR_PTR(-ENOMEM);
}
}
return title;
}
int bpf_program__fd(struct bpf_program *prog)
{
return prog->fd;
}