/* * 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. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; * version 2.1 of the License (not later!) * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, see <http://www.gnu.org/licenses> */ #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" #ifndef EM_BPF #define EM_BPF 247 #endif #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 mismatch", [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", [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type", }; 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; enum bpf_prog_type type; struct { int insn_idx; int map_idx; } *reloc_desc; int nr_reloc; struct { int nr; int *fds; } instances; bpf_program_prep_t preprocessor; struct bpf_object *obj; void *priv; bpf_program_clear_priv_t clear_priv; }; struct bpf_map { int fd; char *name; size_t offset; struct bpf_map_def def; void *priv; bpf_map_clear_priv_t clear_priv; }; static LIST_HEAD(bpf_objects_list); struct bpf_object { char license[64]; u32 kern_version; struct bpf_program *programs; size_t nr_programs; struct bpf_map *maps; size_t nr_maps; 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; size_t strtabidx; struct { GElf_Shdr shdr; Elf_Data *data; } *reloc; int nr_reloc; int maps_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; void *priv; bpf_object_clear_priv_t clear_priv; char path[]; }; #define obj_elf_valid(o) ((o)->efile.elf) static 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_warning("Internal error: instances.nr is %d\n", prog->instances.nr); } prog->instances.nr = -1; zfree(&prog->instances.fds); } 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->instances.fds = NULL; prog->instances.nr = -1; prog->type = BPF_PROG_TYPE_KPROBE; 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->efile.maps_shndx = -1; 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; /* Old LLVM set e_machine to EM_NONE */ if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) { 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__validate_maps(struct bpf_object *obj) { int i; /* * If there's only 1 map, the only error case should have been * catched in bpf_object__init_maps(). */ if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1)) return 0; for (i = 1; i < obj->nr_maps; i++) { const struct bpf_map *a = &obj->maps[i - 1]; const struct bpf_map *b = &obj->maps[i]; if (b->offset - a->offset < sizeof(struct bpf_map_def)) { pr_warning("corrupted map section in %s: map \"%s\" too small\n", obj->path, a->name); return -EINVAL; } } return 0; } static int compare_bpf_map(const void *_a, const void *_b) { const struct bpf_map *a = _a; const struct bpf_map *b = _b; return a->offset - b->offset; } static int bpf_object__init_maps(struct bpf_object *obj) { int i, map_idx, nr_maps = 0; Elf_Scn *scn; Elf_Data *data; Elf_Data *symbols = obj->efile.symbols; if (obj->efile.maps_shndx < 0) return -EINVAL; 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_warning("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. */ for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { GElf_Sym sym; if (!gelf_getsym(symbols, i, &sym)) continue; if (sym.st_shndx != obj->efile.maps_shndx) continue; nr_maps++; } /* Alloc obj->maps and fill nr_maps. */ pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, nr_maps, data->d_size); if (!nr_maps) return 0; obj->maps = calloc(nr_maps, sizeof(obj->maps[0])); if (!obj->maps) { pr_warning("alloc maps for object failed\n"); return -ENOMEM; } obj->nr_maps = nr_maps; /* * 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 = 0; i < nr_maps; i++) obj->maps[i].fd = -1; /* * Fill obj->maps using data in "maps" section. */ for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { GElf_Sym sym; const char *map_name; struct bpf_map_def *def; if (!gelf_getsym(symbols, i, &sym)) continue; if (sym.st_shndx != obj->efile.maps_shndx) continue; map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, sym.st_name); obj->maps[map_idx].offset = sym.st_value; if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) { pr_warning("corrupted maps section in %s: last map \"%s\" too small\n", obj->path, map_name); return -EINVAL; } obj->maps[map_idx].name = strdup(map_name); if (!obj->maps[map_idx].name) { pr_warning("failed to alloc map name\n"); return -ENOMEM; } pr_debug("map %d is \"%s\"\n", map_idx, obj->maps[map_idx].name); def = (struct bpf_map_def *)(data->d_buf + sym.st_value); obj->maps[map_idx].def = *def; map_idx++; } qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map); return bpf_object__validate_maps(obj); } 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) obj->efile.maps_shndx = idx; 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; obj->efile.strtabidx = sh.sh_link; } } 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; 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; } if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) { pr_warning("Corrupted ELF file: index of strtab invalid\n"); return LIBBPF_ERRNO__FORMAT; } if (obj->efile.maps_shndx >= 0) err = bpf_object__init_maps(obj); 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 maps_shndx) { 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; } 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 (sym.st_shndx != maps_shndx) { pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n", prog->section_name, sym.st_shndx); return -LIBBPF_ERRNO__RELOC; } insn_idx = rel.r_offset / sizeof(struct bpf_insn); pr_debug("relocation: insn_idx=%u\n", insn_idx); 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; for (i = 0; i < obj->nr_maps; i++) { struct bpf_map_def *def = &obj->maps[i].def; int *pfd = &obj->maps[i].fd; *pfd = bpf_create_map(def->type, def->key_size, def->value_size, def->max_entries, 0); 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->maps[j].fd); return err; } pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd); } return 0; } static int bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) { 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 = obj->maps[map_idx].fd; } 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); 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->nr_maps; 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, obj->efile.maps_shndx); if (err) return err; } return 0; } static int load_program(enum bpf_prog_type type, 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(type, 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 { /* Wrong program type? */ if (type != BPF_PROG_TYPE_KPROBE) { int fd; fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns, insns_cnt, license, kern_version, NULL, 0); if (fd >= 0) { close(fd); ret = -LIBBPF_ERRNO__PROGTYPE; goto out; } } if (log_buf) 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 = 0, fd, i; if (prog->instances.nr < 0 || !prog->instances.fds) { if (prog->preprocessor) { pr_warning("Internal error: can't load program '%s'\n", prog->section_name); return -LIBBPF_ERRNO__INTERNAL; } prog->instances.fds = malloc(sizeof(int)); if (!prog->instances.fds) { pr_warning("Not enough memory for BPF fds\n"); return -ENOMEM; } prog->instances.nr = 1; prog->instances.fds[0] = -1; } if (!prog->preprocessor) { if (prog->instances.nr != 1) { pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n", prog->section_name, prog->instances.nr); } err = load_program(prog->type, prog->insns, prog->insns_cnt, license, kern_version, &fd); if (!err) prog->instances.fds[0] = fd; goto out; } for (i = 0; i < prog->instances.nr; i++) { struct bpf_prog_prep_result result; bpf_program_prep_t preprocessor = prog->preprocessor; bzero(&result, sizeof(result)); err = preprocessor(prog, i, prog->insns, prog->insns_cnt, &result); if (err) { pr_warning("Preprocessing the %dth instance of program '%s' failed\n", i, prog->section_name); goto out; } if (!result.new_insn_ptr || !result.new_insn_cnt) { pr_debug("Skip loading the %dth instance of program '%s'\n", i, prog->section_name); prog->instances.fds[i] = -1; if (result.pfd) *result.pfd = -1; continue; } err = load_program(prog->type, result.new_insn_ptr, result.new_insn_cnt, license, kern_version, &fd); if (err) { pr_warning("Loading the %dth instance of program '%s' failed\n", i, prog->section_name); goto out; } if (result.pfd) *result.pfd = fd; prog->instances.fds[i] = fd; } out: 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_maps; i++) zclose(obj->maps[i].fd); 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; if (obj->clear_priv) obj->clear_priv(obj, obj->priv); bpf_object__elf_finish(obj); bpf_object__unload(obj); for (i = 0; i < obj->nr_maps; i++) { zfree(&obj->maps[i].name); if (obj->maps[i].clear_priv) obj->maps[i].clear_priv(&obj->maps[i], obj->maps[i].priv); obj->maps[i].priv = NULL; obj->maps[i].clear_priv = NULL; } zfree(&obj->maps); obj->nr_maps = 0; 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__name(struct bpf_object *obj) { return obj ? obj->path : ERR_PTR(-EINVAL); } unsigned int bpf_object__kversion(struct bpf_object *obj) { return obj ? obj->kern_version : 0; } int bpf_object__set_priv(struct bpf_object *obj, void *priv, bpf_object_clear_priv_t clear_priv) { if (obj->priv && obj->clear_priv) obj->clear_priv(obj, obj->priv); obj->priv = priv; obj->clear_priv = clear_priv; return 0; } void *bpf_object__priv(struct bpf_object *obj) { return obj ? obj->priv : ERR_PTR(-EINVAL); } 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_priv(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; } void *bpf_program__priv(struct bpf_program *prog) { return prog ? prog->priv : ERR_PTR(-EINVAL); } 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 bpf_program__nth_fd(prog, 0); } int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, bpf_program_prep_t prep) { int *instances_fds; if (nr_instances <= 0 || !prep) return -EINVAL; if (prog->instances.nr > 0 || prog->instances.fds) { pr_warning("Can't set pre-processor after loading\n"); return -EINVAL; } instances_fds = malloc(sizeof(int) * nr_instances); if (!instances_fds) { pr_warning("alloc memory failed for fds\n"); return -ENOMEM; } /* fill all fd with -1 */ memset(instances_fds, -1, sizeof(int) * nr_instances); prog->instances.nr = nr_instances; prog->instances.fds = instances_fds; prog->preprocessor = prep; return 0; } int bpf_program__nth_fd(struct bpf_program *prog, int n) { int fd; if (n >= prog->instances.nr || n < 0) { pr_warning("Can't get the %dth fd from program %s: only %d instances\n", n, prog->section_name, prog->instances.nr); return -EINVAL; } fd = prog->instances.fds[n]; if (fd < 0) { pr_warning("%dth instance of program '%s' is invalid\n", n, prog->section_name); return -ENOENT; } return fd; } static void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) { prog->type = type; } int bpf_program__set_tracepoint(struct bpf_program *prog) { if (!prog) return -EINVAL; bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT); return 0; } int bpf_program__set_kprobe(struct bpf_program *prog) { if (!prog) return -EINVAL; bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE); return 0; } static bool bpf_program__is_type(struct bpf_program *prog, enum bpf_prog_type type) { return prog ? (prog->type == type) : false; } bool bpf_program__is_tracepoint(struct bpf_program *prog) { return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT); } bool bpf_program__is_kprobe(struct bpf_program *prog) { return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE); } int bpf_map__fd(struct bpf_map *map) { return map ? map->fd : -EINVAL; } const struct bpf_map_def *bpf_map__def(struct bpf_map *map) { return map ? &map->def : ERR_PTR(-EINVAL); } const char *bpf_map__name(struct bpf_map *map) { return map ? map->name : NULL; } int bpf_map__set_priv(struct bpf_map *map, void *priv, bpf_map_clear_priv_t clear_priv) { if (!map) return -EINVAL; if (map->priv) { if (map->clear_priv) map->clear_priv(map, map->priv); } map->priv = priv; map->clear_priv = clear_priv; return 0; } void *bpf_map__priv(struct bpf_map *map) { return map ? map->priv : ERR_PTR(-EINVAL); } struct bpf_map * bpf_map__next(struct bpf_map *prev, struct bpf_object *obj) { size_t idx; struct bpf_map *s, *e; if (!obj || !obj->maps) return NULL; s = obj->maps; e = obj->maps + obj->nr_maps; if (prev == NULL) return s; if ((prev < s) || (prev >= e)) { pr_warning("error in %s: map handler doesn't belong to object\n", __func__); return NULL; } idx = (prev - obj->maps) + 1; if (idx >= obj->nr_maps) return NULL; return &obj->maps[idx]; } struct bpf_map * bpf_object__find_map_by_name(struct bpf_object *obj, const char *name) { struct bpf_map *pos; bpf_map__for_each(pos, obj) { if (pos->name && !strcmp(pos->name, name)) return pos; } return NULL; } struct bpf_map * bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) { int i; for (i = 0; i < obj->nr_maps; i++) { if (obj->maps[i].offset == offset) return &obj->maps[i]; } return ERR_PTR(-ENOENT); }