1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #include <stdio.h> 28 #include <string.h> 29 #include <sys/types.h> 30 #include <sys/stat.h> 31 #include <fcntl.h> 32 #include <unistd.h> 33 #include <libelf.h> 34 #include <gelf.h> 35 #include <errno.h> 36 37 /* 38 * symdef is a very simplified version of nm. It is used by upgrade and 39 * create_ramdisk in situations where we can't guarantee that nm will be around. 40 * 41 * Two arguments are expected: a binary and a symbol name. If the symbol is 42 * found in the name table of the binary, 0 is returned. If it is not found, 43 * 1 is returned. If an error occurs, a message is printed to stderr and -1 44 * is returned. 45 */ 46 47 48 static void 49 usage(void) 50 { 51 (void) fprintf(stderr, "USAGE: symdef file_name symbol\n"); 52 } 53 54 int 55 main(int argc, char *argv[]) 56 { 57 int fd = 0; 58 int rv = 1; 59 uint_t cnt, symcnt; 60 Elf *elfp = NULL; 61 Elf_Scn *scn = NULL; 62 size_t shstrndx; 63 GElf_Ehdr ehdr; 64 GElf_Shdr shdr; 65 GElf_Sym sym; 66 Elf32_Word shndx; 67 Elf_Data *symdata, *shndxdata; 68 69 if (argc != 3) { 70 usage(); 71 return (-1); 72 } 73 74 fd = open(argv[1], O_RDONLY); 75 if (fd == -1) { 76 (void) fprintf(stderr, "%s\n", strerror(errno)); 77 rv = -1; 78 goto done; 79 } 80 if (elf_version(EV_CURRENT) == EV_NONE) { 81 (void) fprintf(stderr, "Elf library version out of date\n"); 82 rv = -1; 83 goto done; 84 } 85 elfp = elf_begin(fd, ELF_C_READ, NULL); 86 if ((elfp == NULL) || (elf_kind(elfp) != ELF_K_ELF) || 87 ((gelf_getehdr(elfp, &ehdr)) == NULL) || 88 (elf_getshstrndx(elfp, &shstrndx) == 0)) 89 goto done; 90 91 while ((scn = elf_nextscn(elfp, scn)) != NULL) { 92 if ((gelf_getshdr(scn, &shdr) == NULL) || 93 ((shdr.sh_type != SHT_SYMTAB) && 94 (shdr.sh_type != SHT_DYNSYM)) || 95 ((symdata = elf_getdata(scn, NULL)) == NULL)) 96 continue; 97 symcnt = shdr.sh_size / shdr.sh_entsize; 98 shndxdata = NULL; 99 for (cnt = 0; cnt < symcnt; cnt++) { 100 if ((gelf_getsymshndx(symdata, shndxdata, cnt, 101 &sym, &shndx) != NULL) && 102 (strcmp(argv[2], elf_strptr(elfp, shdr.sh_link, 103 sym.st_name)) == 0)) { 104 rv = 0; 105 goto done; 106 } 107 } 108 } 109 done: 110 if (elfp) 111 (void) elf_end(elfp); 112 if (fd != -1) 113 (void) close(fd); 114 return (rv); 115 } 116