diff options
Diffstat (limited to 'src/vppinfra/elf_clib.c')
| -rw-r--r-- | src/vppinfra/elf_clib.c | 377 |
1 files changed, 377 insertions, 0 deletions
diff --git a/src/vppinfra/elf_clib.c b/src/vppinfra/elf_clib.c new file mode 100644 index 00000000..7bb72ee3 --- /dev/null +++ b/src/vppinfra/elf_clib.c @@ -0,0 +1,377 @@ +/* + * 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: + */ |