From: Alastair Robertson Date: Wed, 11 Dec 2024 16:40:29 +0000 (-0800) Subject: libbpf: Pull file-opening logic up to top-level functions X-Git-Tag: v6.14-rc1~133^2~48^2~1 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=b641712925bfe89ff7217cc2d0b7a8e042df556b;p=linux-block.git libbpf: Pull file-opening logic up to top-level functions Move the filename arguments and file-descriptor handling from init_output_elf() and linker_load_obj_file() and instead handle them at the top-level in bpf_linker__new() and bpf_linker__add_file(). This will allow the inner functions to be shared with a new, non-filename-based, API in the next commit. Signed-off-by: Alastair Robertson Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20241211164030.573042-2-ajor@meta.com --- diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index e56ba6e67451..c49e94506d9c 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -157,10 +157,9 @@ struct bpf_linker { #define pr_warn_elf(fmt, ...) \ libbpf_print(LIBBPF_WARN, "libbpf: " fmt ": %s\n", ##__VA_ARGS__, elf_errmsg(-1)) -static int init_output_elf(struct bpf_linker *linker, const char *file); +static int init_output_elf(struct bpf_linker *linker); -static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, - const struct bpf_linker_file_opts *opts, +static int linker_load_obj_file(struct bpf_linker *linker, struct src_obj *obj); static int linker_sanity_check_elf(struct src_obj *obj); static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec); @@ -233,9 +232,20 @@ struct bpf_linker *bpf_linker__new(const char *filename, struct bpf_linker_opts if (!linker) return errno = ENOMEM, NULL; - linker->fd = -1; + linker->filename = strdup(filename); + if (!linker->filename) { + err = -ENOMEM; + goto err_out; + } + + linker->fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0644); + if (linker->fd < 0) { + err = -errno; + pr_warn("failed to create '%s': %d\n", filename, err); + goto err_out; + } - err = init_output_elf(linker, filename); + err = init_output_elf(linker); if (err) goto err_out; @@ -294,23 +304,12 @@ static Elf64_Sym *add_new_sym(struct bpf_linker *linker, size_t *sym_idx) return sym; } -static int init_output_elf(struct bpf_linker *linker, const char *file) +static int init_output_elf(struct bpf_linker *linker) { int err, str_off; Elf64_Sym *init_sym; struct dst_sec *sec; - linker->filename = strdup(file); - if (!linker->filename) - return -ENOMEM; - - linker->fd = open(file, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0644); - if (linker->fd < 0) { - err = -errno; - pr_warn("failed to create '%s': %s\n", file, errstr(err)); - return err; - } - linker->elf = elf_begin(linker->fd, ELF_C_WRITE, NULL); if (!linker->elf) { pr_warn_elf("failed to create ELF object"); @@ -440,7 +439,7 @@ int bpf_linker__add_file(struct bpf_linker *linker, const char *filename, const struct bpf_linker_file_opts *opts) { struct src_obj obj = {}; - int err = 0; + int err = 0, fd; if (!OPTS_VALID(opts, bpf_linker_file_opts)) return libbpf_err(-EINVAL); @@ -448,7 +447,17 @@ int bpf_linker__add_file(struct bpf_linker *linker, const char *filename, if (!linker->elf) return libbpf_err(-EINVAL); - err = err ?: linker_load_obj_file(linker, filename, opts, &obj); + fd = open(filename, O_RDONLY | O_CLOEXEC); + if (fd < 0) { + err = -errno; + pr_warn("failed to open file '%s': %s\n", filename, errstr(err)); + return libbpf_err(err); + } + + obj.filename = filename; + obj.fd = fd; + + err = err ?: linker_load_obj_file(linker, &obj); err = err ?: linker_append_sec_data(linker, &obj); err = err ?: linker_append_elf_syms(linker, &obj); err = err ?: linker_append_elf_relos(linker, &obj); @@ -534,8 +543,7 @@ static struct src_sec *add_src_sec(struct src_obj *obj, const char *sec_name) return sec; } -static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, - const struct bpf_linker_file_opts *opts, +static int linker_load_obj_file(struct bpf_linker *linker, struct src_obj *obj) { int err = 0; @@ -554,26 +562,18 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, #error "Unknown __BYTE_ORDER__" #endif - pr_debug("linker: adding object file '%s'...\n", filename); - - obj->filename = filename; + pr_debug("linker: adding object file '%s'...\n", obj->filename); - obj->fd = open(filename, O_RDONLY | O_CLOEXEC); - if (obj->fd < 0) { - err = -errno; - pr_warn("failed to open file '%s': %s\n", filename, errstr(err)); - return err; - } obj->elf = elf_begin(obj->fd, ELF_C_READ_MMAP, NULL); if (!obj->elf) { - pr_warn_elf("failed to parse ELF file '%s'", filename); + pr_warn_elf("failed to parse ELF file '%s'", obj->filename); return -EINVAL; } /* Sanity check ELF file high-level properties */ ehdr = elf64_getehdr(obj->elf); if (!ehdr) { - pr_warn_elf("failed to get ELF header for %s", filename); + pr_warn_elf("failed to get ELF header for %s", obj->filename); return -EINVAL; } @@ -581,7 +581,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, obj_byteorder = ehdr->e_ident[EI_DATA]; if (obj_byteorder != ELFDATA2LSB && obj_byteorder != ELFDATA2MSB) { err = -EOPNOTSUPP; - pr_warn("unknown byte order of ELF file %s\n", filename); + pr_warn("unknown byte order of ELF file %s\n", obj->filename); return err; } if (link_byteorder == ELFDATANONE) { @@ -591,7 +591,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, obj_byteorder == ELFDATA2MSB ? "big" : "little"); } else if (link_byteorder != obj_byteorder) { err = -EOPNOTSUPP; - pr_warn("byte order mismatch with ELF file %s\n", filename); + pr_warn("byte order mismatch with ELF file %s\n", obj->filename); return err; } @@ -599,12 +599,12 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, || ehdr->e_machine != EM_BPF || ehdr->e_ident[EI_CLASS] != ELFCLASS64) { err = -EOPNOTSUPP; - pr_warn_elf("unsupported kind of ELF file %s", filename); + pr_warn_elf("unsupported kind of ELF file %s", obj->filename); return err; } if (elf_getshdrstrndx(obj->elf, &obj->shstrs_sec_idx)) { - pr_warn_elf("failed to get SHSTRTAB section index for %s", filename); + pr_warn_elf("failed to get SHSTRTAB section index for %s", obj->filename); return -EINVAL; } @@ -616,21 +616,21 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, shdr = elf64_getshdr(scn); if (!shdr) { pr_warn_elf("failed to get section #%zu header for %s", - sec_idx, filename); + sec_idx, obj->filename); return -EINVAL; } sec_name = elf_strptr(obj->elf, obj->shstrs_sec_idx, shdr->sh_name); if (!sec_name) { pr_warn_elf("failed to get section #%zu name for %s", - sec_idx, filename); + sec_idx, obj->filename); return -EINVAL; } data = elf_getdata(scn, 0); if (!data) { pr_warn_elf("failed to get section #%zu (%s) data from %s", - sec_idx, sec_name, filename); + sec_idx, sec_name, obj->filename); return -EINVAL; } @@ -666,7 +666,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, err = libbpf_get_error(obj->btf); if (err) { pr_warn("failed to parse .BTF from %s: %s\n", - filename, errstr(err)); + obj->filename, errstr(err)); return err; } sec->skipped = true; @@ -677,7 +677,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, err = libbpf_get_error(obj->btf_ext); if (err) { pr_warn("failed to parse .BTF.ext from '%s': %s\n", - filename, errstr(err)); + obj->filename, errstr(err)); return err; } sec->skipped = true; @@ -694,7 +694,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, break; default: pr_warn("unrecognized section #%zu (%s) in %s\n", - sec_idx, sec_name, filename); + sec_idx, sec_name, obj->filename); err = -EINVAL; return err; }