/* * Copyright (c) 2015 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vppinfra/elf_clib.h> #include <stdlib.h> #include <fcntl.h> #include <sys/stat.h> typedef struct { char **path; } path_search_t; always_inline void path_search_free (path_search_t * p) { uword i; for (i = 0; i < vec_len (p->path); i++) vec_free (p->path[i]); vec_free (p->path); } static char ** split_string (char *string, u8 delimiter) { char **result = 0; char *p, *start, *s; p = string; while (1) { start = p; while (*p != 0 && *p != delimiter) p++; s = 0; vec_add (s, start, p - start); vec_add1 (s, 0); vec_add1 (result, s); if (*p == 0) break; p++; } return result; } static int file_exists_and_is_executable (char *dir, char *file) { char *path = (char *) format (0, "%s/%s%c", dir, file, 0); struct stat s; uword yes; yes = (stat (path, &s) >= 0 && S_ISREG (s.st_mode) && 0 != (s.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))); vec_free (path); return yes; } static char * path_search (char *file) { path_search_t ps; uword i; char *result; /* Relative or absolute path. */ if (file[0] == '.' || file[0] == '/') return file; if (getenv ("PATH") == 0) return file; ps.path = split_string (getenv ("PATH"), ':'); for (i = 0; i < vec_len (ps.path); i++) if (file_exists_and_is_executable (ps.path[i], file)) break; result = 0; if (i < vec_len (ps.path)) result = (char *) format (0, "%s/%s%c", ps.path[i], file); path_search_free (&ps); return result; } static clib_error_t * clib_elf_parse_file (clib_elf_main_t * cem, char *file_name, void *link_address) { elf_main_t *em; elf_section_t *s; int fd; struct stat fd_stat; uword mmap_length = 0; void *data = 0; clib_error_t *error = 0; vec_add2 (cem->elf_mains, em, 1); fd = open (file_name, 0); if (fd < 0) { error = clib_error_return_unix (0, "open `%s'", file_name); goto done; } if (fstat (fd, &fd_stat) < 0) { error = clib_error_return_unix (0, "fstat `%s'", file_name); goto done; } mmap_length = fd_stat.st_size; data = mmap (0, mmap_length, PROT_READ, MAP_SHARED, fd, /* offset */ 0); if (~pointer_to_uword (data) == 0) { error = clib_error_return_unix (0, "mmap `%s'", file_name); goto done; } error = elf_parse (em, data, mmap_length); if (error) goto done; /* Look for CLIB special sections. */ { char *section_name_start = CLIB_ELF_SECTION_ADD_PREFIX (); uword section_name_start_len = strlen (section_name_start); vec_foreach (s, em->sections) { u8 *name = elf_section_name (em, s); uword *p; clib_elf_section_t *vs; clib_elf_section_bounds_t *b; /* Section name must begin with CLIB_ELF_SECTION key. */ if (memcmp (name, section_name_start, section_name_start_len)) continue; name += section_name_start_len; p = hash_get_mem (cem->section_by_name, name); if (p) vs = vec_elt_at_index (cem->sections, p[0]); else { name = format (0, "%s%c", name, 0); if (!cem->section_by_name) cem->section_by_name = hash_create_string (0, sizeof (uword)); hash_set_mem (cem->section_by_name, name, vec_len (cem->sections)); vec_add2 (cem->sections, vs, 1); vs->name = name; } vec_add2 (vs->bounds, b, 1); b->lo = link_address + s->header.exec_address; b->hi = b->lo + s->header.file_size; } } /* Parse symbols for this file. */ { elf_symbol_table_t *t; elf64_symbol_t *s; elf_parse_symbols (em); vec_foreach (t, em->symbol_tables) { vec_foreach (s, t->symbols) { s->value += pointer_to_uword (link_address); } } } /* No need to keep section contents around. */ { elf_section_t *s; vec_foreach (s, em->sections) { if (s->header.type != ELF_SECTION_STRING_TABLE) vec_free (s->contents); } } done: if (error) elf_main_free (em); if (fd >= 0) close (fd); if (data) munmap (data, mmap_length); return error; } #define __USE_GNU #include <link.h> static int add_section (struct dl_phdr_info *info, size_t size, void *opaque) { clib_elf_main_t *cem = opaque; clib_error_t *error; char *name = (char *) info->dlpi_name; void *addr = (void *) info->dlpi_addr; uword is_main; is_main = strlen (name) == 0; if (is_main) { static int done; /* Only do main program once. */ if (done++) return 0; name = path_search (cem->exec_path); if (!name) { clib_error ("failed to find %s on PATH", cem->exec_path); return 0; } addr = 0; } error = clib_elf_parse_file (cem, name, addr); if (error) clib_error_report (error); if (is_main && name != cem->exec_path) vec_free (name); return 0; } static clib_elf_main_t clib_elf_main; void clib_elf_main_init (char *exec_path) { clib_elf_main_t *cem = &clib_elf_main; cem->exec_path = exec_path; dl_iterate_phdr (add_section, cem); } clib_elf_section_bounds_t * clib_elf_get_section_bounds (char *name) { clib_elf_main_t *em = &clib_elf_main; uword *p = hash_get (em->section_by_name, name); return p ? vec_elt_at_index (em->sections, p[0])->bounds : 0; } static uword symbol_by_address_or_name (char *by_name, uword by_address, clib_elf_symbol_t * s) { clib_elf_main_t *cem = &clib_elf_main; elf_main_t *em; vec_foreach (em, cem->elf_mains) { elf_symbol_table_t *t; s->elf_main_index = em - cem->elf_mains; vec_foreach (t, em->symbol_tables) { s->symbol_table_index = t - em->symbol_tables; if (by_name) { uword *p = hash_get (t->symbol_by_name, by_name); if (p) { s->symbol = vec_elt (t->symbols, p[0]); return 1; } } else { elf64_symbol_t *x; /* FIXME linear search. */ vec_foreach (x, t->symbols) { if (by_address >= x->value && by_address < x->value + x->size) { s->symbol = x[0]; return 1; } } } } } return 0; } uword clib_elf_symbol_by_name (char *by_name, clib_elf_symbol_t * s) { return symbol_by_address_or_name (by_name, /* by_address */ 0, s); } uword clib_elf_symbol_by_address (uword by_address, clib_elf_symbol_t * s) { return symbol_by_address_or_name ( /* by_name */ 0, by_address, s); } u8 * format_clib_elf_symbol (u8 * s, va_list * args) { clib_elf_main_t *cem = &clib_elf_main; clib_elf_symbol_t *sym = va_arg (*args, clib_elf_symbol_t *); elf_main_t *em; elf_symbol_table_t *t; if (!sym) /* Just print table headings. */ return format (s, "%U", format_elf_symbol, 0, 0, 0); else { em = vec_elt_at_index (cem->elf_mains, sym->elf_main_index); t = vec_elt_at_index (em->symbol_tables, sym->symbol_table_index); return format (s, "%U", format_elf_symbol, em, t, &sym->symbol); } } u8 * format_clib_elf_symbol_with_address (u8 * s, va_list * args) { uword address = va_arg (*args, uword); clib_elf_main_t *cem = &clib_elf_main; clib_elf_symbol_t sym; elf_main_t *em; elf_symbol_table_t *t; if (clib_elf_symbol_by_address (address, &sym)) { em = vec_elt_at_index (cem->elf_mains, sym.elf_main_index); t = vec_elt_at_index (em->symbol_tables, sym.symbol_table_index); s = format (s, "%s + 0x%wx", elf_symbol_name (t, &sym.symbol), address - sym.symbol.value); } else s = format (s, "0x%wx", address); return s; } /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */