diff options
-rw-r--r-- | tools/lib/bpf/libbpf.c | 124 | ||||
-rw-r--r-- | tools/lib/bpf/libbpf.h | 13 |
2 files changed, 137 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e8088f8214d1..ac69ae3bd628 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9,6 +9,7 @@ #include <stdlib.h> #include <stdio.h> #include <stdarg.h> +#include <inttypes.h> #include <string.h> #include <unistd.h> #include <fcntl.h> @@ -88,6 +89,12 @@ struct bpf_program { char *section_name; struct bpf_insn *insns; size_t insns_cnt; + + struct { + int insn_idx; + int map_idx; + } *reloc_desc; + int nr_reloc; }; struct bpf_object { @@ -127,6 +134,9 @@ static void bpf_program__exit(struct bpf_program *prog) zfree(&prog->section_name); zfree(&prog->insns); + zfree(&prog->reloc_desc); + + prog->nr_reloc = 0; prog->insns_cnt = 0; prog->idx = -1; } @@ -481,6 +491,118 @@ 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 -EINVAL; + } + + 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 -EINVAL; + } + + 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 -EINVAL; + } + + 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 -EINVAL; + } + + prog->reloc_desc[i].insn_idx = insn_idx; + prog->reloc_desc[i].map_idx = map_idx; + } + 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 -EINVAL; + } + + 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 -EINVAL; + } + + prog = bpf_object__find_prog_by_idx(obj, idx); + if (!prog) { + pr_warning("relocation failed: no %d section\n", + idx); + return -ENOENT; + } + + err = bpf_program__collect_reloc(prog, nr_maps, + shdr, data, + obj->efile.symbols); + if (err) + return -EINVAL; + } + return 0; +} + static int bpf_object__validate(struct bpf_object *obj) { if (obj->kern_version == 0) { @@ -511,6 +633,8 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) goto out; if (bpf_object__elf_collect(obj)) goto out; + if (bpf_object__collect_reloc(obj)) + goto out; if (bpf_object__validate(obj)) goto out; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index dc966dd9fd75..6e75acdb9112 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -30,4 +30,17 @@ struct bpf_object *bpf_object__open_buffer(void *obj_buf, size_t obj_buf_sz); void bpf_object__close(struct bpf_object *object); +/* + * We don't need __attribute__((packed)) now since it is + * unnecessary for 'bpf_map_def' because they are all aligned. + * In addition, using it will trigger -Wpacked warning message, + * and will be treated as an error due to -Werror. + */ +struct bpf_map_def { + unsigned int type; + unsigned int key_size; + unsigned int value_size; + unsigned int max_entries; +}; + #endif |