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 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <stdio.h> 30 #include <string.h> 31 #include <sys/types.h> 32 #include <sys/stat.h> 33 #include <fcntl.h> 34 #include <unistd.h> 35 #include <libelf.h> 36 #include <gelf.h> 37 #include <errno.h> 38 39 /* 40 * symdef is a very simplified version of nm. It is used by upgrade and 41 * create_ramdisk in situations where we can't guarantee that nm will be around. 42 * 43 * Two arguments are expected: a binary and a symbol name. If the symbol is 44 * found in the name table of the binary, 0 is returned. If it is not found, 45 * 1 is returned. If an error occurs, a message is printed to stderr and -1 46 * is returned. 47 */ 48 49 50 static void 51 usage(void) 52 { 53 (void) fprintf(stderr, "USAGE: symdef file_name symbol\n"); 54 } 55 56 int 57 main(int argc, char *argv[]) 58 { 59 int fd = 0; 60 int rv = 1; 61 uint_t cnt, symcnt; 62 Elf *elfp = NULL; 63 Elf_Scn *scn = NULL; 64 size_t shstrndx; 65 GElf_Ehdr ehdr; 66 GElf_Shdr shdr; 67 GElf_Sym sym; 68 Elf32_Word shndx; 69 Elf_Data *symdata, *shndxdata; 70 71 if (argc != 3) { 72 usage(); 73 return (-1); 74 } 75 76 fd = open(argv[1], O_RDONLY); 77 if (fd == -1) { 78 (void) fprintf(stderr, "%s\n", strerror(errno)); 79 rv = -1; 80 goto done; 81 } 82 if (elf_version(EV_CURRENT) == EV_NONE) { 83 (void) fprintf(stderr, "Elf library version out of date\n"); 84 rv = -1; 85 goto done; 86 } 87 elfp = elf_begin(fd, ELF_C_READ, NULL); 88 if ((elfp == NULL) || (elf_kind(elfp) != ELF_K_ELF) || 89 ((gelf_getehdr(elfp, &ehdr)) == NULL) || 90 (elf_getshstrndx(elfp, &shstrndx) == 0)) 91 goto done; 92 93 while ((scn = elf_nextscn(elfp, scn)) != NULL) { 94 if ((gelf_getshdr(scn, &shdr) == NULL) || 95 ((shdr.sh_type != SHT_SYMTAB) && 96 (shdr.sh_type != SHT_DYNSYM)) || 97 ((symdata = elf_getdata(scn, NULL)) == NULL)) 98 continue; 99 symcnt = shdr.sh_size / shdr.sh_entsize; 100 shndxdata = NULL; 101 for (cnt = 0; cnt < symcnt; cnt++) { 102 if ((gelf_getsymshndx(symdata, shndxdata, cnt, 103 &sym, &shndx) != NULL) && 104 (strcmp(argv[2], elf_strptr(elfp, shdr.sh_link, 105 sym.st_name)) == 0)) { 106 rv = 0; 107 goto done; 108 } 109 } 110 } 111 done: 112 if (elfp) 113 (void) elf_end(elfp); 114 if (fd != -1) 115 (void) close(fd); 116 return (rv); 117 } 118