diff options
Diffstat (limited to 'vppinfra/tools/elftool.c')
| -rw-r--r-- | vppinfra/tools/elftool.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/vppinfra/tools/elftool.c b/vppinfra/tools/elftool.c new file mode 100644 index 00000000..c0184b5c --- /dev/null +++ b/vppinfra/tools/elftool.c @@ -0,0 +1,459 @@ +/* + * 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. + */ +/* + Copyright (c) 2008 Eliot Dresselhaus + + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + "Software"), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, subject to + the following conditions: + + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +*/ + +#include <vppinfra/elf.h> + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + +#ifndef CLIB_UNIX +#error "unix only" +#endif + +typedef struct { + elf_main_t elf_main; + char * input_file; + char * output_file; + char * set_interpreter; + char * set_rpath; + int unset_rpath; + int verbose; + int quiet; + int allow_elf_shared; + /* for use in the optimized / simplified case */ + u64 file_size; + u64 interpreter_offset; + u64 rpath_offset; +} elf_tool_main_t; + +static clib_error_t * elf_set_interpreter (elf_main_t * em, + elf_tool_main_t * tm) +{ + elf_segment_t * g; + elf_section_t * s; + clib_error_t * error; + char * interp = tm->set_interpreter; + + switch (em->first_header.file_type) + { + case ELF_EXEC: + break; + + case ELF_SHARED: + if (tm->allow_elf_shared) + break; + /* Note flowthrough */ + default: + return clib_error_return (0, "unacceptable file_type"); + } + + vec_foreach (g, em->segments) + { + if (g->header.type == ELF_SEGMENT_INTERP) + break; + } + + if (g >= vec_end (em->segments)) + return clib_error_return (0, "interpreter not found"); + + if (g->header.memory_size < 1 + strlen (interp)) + return clib_error_return (0, "given interpreter does not fit; must be less than %d bytes (`%s' given)", + g->header.memory_size, interp); + + error = elf_get_section_by_start_address (em, g->header.virtual_address, &s); + if (error) + return error; + + /* Put in new null terminated string. */ + memset (s->contents, 0, vec_len (s->contents)); + memcpy (s->contents, interp, strlen (interp)); + + return 0; +} + +static void +delete_rpath_for_section (elf_main_t * em, elf_section_t * s) +{ + elf64_dynamic_entry_t * e; + elf64_dynamic_entry_t * new_es = 0; + + vec_foreach (e, em->dynamic_entries) + { + switch (e->type) + { + case ELF_DYNAMIC_ENTRY_RPATH: + case ELF_DYNAMIC_ENTRY_RUN_PATH: + break; + + default: + vec_add1 (new_es, e[0]); + break; + } + } + + /* Pad so as to keep section size constant. */ + { + elf64_dynamic_entry_t e_end; + e_end.type = ELF_DYNAMIC_ENTRY_END; + e_end.data = 0; + while (vec_len (new_es) < vec_len (em->dynamic_entries)) + vec_add1 (new_es, e_end); + } + + vec_free (em->dynamic_entries); + em->dynamic_entries = new_es; + + elf_set_dynamic_entries (em); +} + +static void delete_rpath (elf_main_t * em) +{ + elf_section_t * s; + + vec_foreach (s, em->sections) + { + switch (s->header.type) + { + case ELF_SECTION_DYNAMIC: + delete_rpath_for_section (em, s); + break; + + default: + break; + } + } +} + +static clib_error_t * +set_rpath_for_section (elf_main_t * em, elf_section_t * s, char * new_rpath) +{ + elf64_dynamic_entry_t * e; + char * old_rpath; + int old_len, new_len = strlen (new_rpath); + u8 * new_string_table = vec_dup (em->dynamic_string_table); + + vec_foreach (e, em->dynamic_entries) + { + switch (e->type) + { + case ELF_DYNAMIC_ENTRY_RPATH: + case ELF_DYNAMIC_ENTRY_RUN_PATH: + old_rpath = (char *) new_string_table + e->data; + old_len = strlen (old_rpath); + if (old_len < new_len) + return clib_error_return (0, "rpath of `%s' does not fit (old rpath `%s')", + new_rpath, old_rpath); + strcpy (old_rpath, new_rpath); + break; + + default: + break; + } + } + + elf_set_section_contents (em, em->dynamic_string_table_section_index, + new_string_table, + vec_bytes (new_string_table)); + + return 0; +} + +static clib_error_t * +set_rpath (elf_main_t * em, char * rpath) +{ + clib_error_t * error = 0; + elf_section_t * s; + + vec_foreach (s, em->sections) + { + switch (s->header.type) + { + case ELF_SECTION_DYNAMIC: + error = set_rpath_for_section (em, s, rpath); + if (error) + return error; + break; + + default: + break; + } + } + + return error; +} + +static clib_error_t * +set_interpreter_rpath (elf_tool_main_t * tm) +{ + int ifd = -1, ofd = -1; + struct stat fd_stat; + u8 *idp = 0; /* warning be gone */ + u64 mmap_length = 0, i; + u32 run_length; + u8 in_run; + u64 offset0 = 0, offset1 = 0; + clib_error_t * error; + int fix_in_place = 0; + + if (!strcmp (tm->input_file, tm->output_file)) + fix_in_place = 1; + + ifd = open (tm->input_file, O_RDWR); + if (ifd < 0) + { + error = clib_error_return_unix (0, "open `%s'", tm->input_file); + goto done; + } + + if (fstat (ifd, &fd_stat) < 0) + { + error = clib_error_return_unix (0, "fstat `%s'", tm->input_file); + goto done; + } + + if (!(fd_stat.st_mode & S_IFREG)) + { + error = clib_error_return (0, "%s is not a regular file", tm->input_file); + goto done; + } + + mmap_length = fd_stat.st_size; + if (mmap_length < 4) + { + error = clib_error_return (0, "%s too short", tm->input_file); + goto done; + } + + /* COW-mapping, since we intend to write the fixups */ + if (fix_in_place) + idp = mmap (0, mmap_length, PROT_READ | PROT_WRITE, MAP_SHARED, + ifd, /* offset */ 0); + else + idp = mmap (0, mmap_length, PROT_READ | PROT_WRITE, MAP_PRIVATE, + ifd, /* offset */ 0); + if (~pointer_to_uword (idp) == 0) + { + mmap_length = 0; + error = clib_error_return_unix (0, "mmap `%s'", tm->input_file); + goto done; + } + + if (idp[0] != 0x7f || idp[1] != 'E' || idp[2] != 'L' || idp[3] != 'F') + { + error = clib_error_return (0, "not an ELF file '%s'", tm->input_file); + goto done; + } + + in_run = 0; + run_length = 0; + + for (i = 0; i < mmap_length; i++) + { + if (idp[i] == '/') + { + if (in_run) + run_length++; + else + { + in_run = 1; + run_length = 1; + } + } + else + { + if (in_run && run_length >= 16) + { + if (offset0 == 0) + offset0 = (i - run_length); + else if (offset1 == 0) + { + offset1 = (i - run_length); + goto found_both; + } + } + in_run = 0; + run_length = 0; + } + } + + if (offset0 == 0) + { + error = clib_error_return (0, "no fixup markers in %s", + tm->input_file); + goto done; + } + + found_both: + if (0) + clib_warning ("offset0 %lld (0x%llx), offset1 %lld (0x%llx)", + offset0, offset0, offset1, offset1); + + /* Executable file case */ + if (offset0 && offset1) + { + tm->interpreter_offset = offset0; + tm->rpath_offset = offset1; + } + else /* shared library case */ + { + tm->interpreter_offset = 0; + tm->rpath_offset = offset0; + } + + if (tm->interpreter_offset) + memcpy (&idp[tm->interpreter_offset], tm->set_interpreter, + strlen (tm->set_interpreter)+1); + + if (tm->rpath_offset) + memcpy (&idp[tm->rpath_offset], tm->set_rpath, + strlen (tm->set_rpath)+1); + + /* Write the output file... */ + if (fix_in_place == 0) + { + ofd = open (tm->output_file, O_RDWR | O_CREAT | O_TRUNC, 0644); + if (ofd < 0) + { + error = clib_error_return_unix (0, "create `%s'", tm->output_file); + goto done; + } + + if (write (ofd, idp, mmap_length) != mmap_length) + error = clib_error_return_unix (0, "write `%s'", tm->output_file); + } + + done: + if (mmap_length > 0) + munmap (idp, mmap_length); + close (ifd); + close (ofd); + return error; +} + + +int main (int argc, char * argv[]) +{ + elf_tool_main_t _tm, * tm = &_tm; + elf_main_t * em = &tm->elf_main; + unformat_input_t i; + clib_error_t * error = 0; + + memset (tm, 0, sizeof (tm[0])); + unformat_init_command_line (&i, argv); + + while (unformat_check_input (&i) != UNFORMAT_END_OF_INPUT) + { + if (unformat (&i, "in %s", &tm->input_file)) + ; + else if (unformat (&i, "out %s", &tm->output_file)) + ; + else if (unformat (&i, "set-interpreter %s", &tm->set_interpreter)) + ; + else if (unformat (&i, "set-rpath %s", &tm->set_rpath)) + ; + else if (unformat (&i, "unset-rpath")) + tm->unset_rpath = 1; + else if (unformat (&i, "verbose")) + tm->verbose = ~0; + else if (unformat (&i, "verbose-symbols")) + tm->verbose |= FORMAT_ELF_MAIN_SYMBOLS; + else if (unformat (&i, "verbose-relocations")) + tm->verbose |= FORMAT_ELF_MAIN_RELOCATIONS; + else if (unformat (&i, "verbose-dynamic")) + tm->verbose |= FORMAT_ELF_MAIN_DYNAMIC; + else if (unformat (&i, "quiet")) + tm->quiet = 1; + else if (unformat (&i, "allow-elf-shared")) + tm->allow_elf_shared = 1; + else + { + error = unformat_parse_error (&i); + goto done; + } + } + + if (! tm->input_file) + clib_error ("no input file"); + + /* Do the typical case a stone-simple way... */ + if (tm->quiet && tm->set_interpreter && tm->set_rpath && tm->output_file) + { + error = set_interpreter_rpath (tm); + goto done; + } + + error = elf_read_file (em, tm->input_file); + + if (error) + goto done; + + if (tm->verbose) + fformat (stdout, "%U", format_elf_main, em, tm->verbose); + + if (tm->set_interpreter) + { + error = elf_set_interpreter (em, tm); + if (error) + goto done; + } + + if (tm->set_rpath) + { + error = set_rpath (em, tm->set_rpath); + if (error) + goto done; + } + + if (tm->unset_rpath) + delete_rpath (em); + + if (tm->output_file) + error = elf_write_file (em, tm->output_file); + + elf_main_free (em); + + done: + if (error) + { + if (tm->quiet == 0) + clib_error_report (error); + return 1; + } + else + return 0; +} |