1/*- 2 * Copyright (c) 2006 Joseph Koshy 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD$"); 29 30#include <sys/types.h> 31#include <sys/errno.h> 32#include <sys/mman.h> 33#include <sys/stat.h> 34 35#include <ar.h> 36#include <ctype.h> 37#include <libelf.h> 38#include <unistd.h> 39 40#include "_libelf.h" 41 42static Elf * 43_libelf_open_object(int fd, Elf_Cmd c) 44{ 45 Elf *e; 46 void *m; 47 struct stat sb; 48 49 /* 50 * 'Raw' files are always mapped with 'PROT_READ'. At 51 * elf_update(3) time for files opened with ELF_C_RDWR the 52 * mapping is unmapped, file data is written to using write(2) 53 * and then the raw data is immediately mapped back in. 54 */ 55 if (fstat(fd, &sb) < 0) { 56 LIBELF_SET_ERROR(IO, errno); 57 return (NULL); 58 } 59 60 m = NULL; 61 if ((m = mmap(NULL, (size_t) sb.st_size, PROT_READ, MAP_PRIVATE, fd, 62 (off_t) 0)) == MAP_FAILED) { 63 LIBELF_SET_ERROR(IO, errno); 64 return (NULL); 65 } 66 67 if ((e = elf_memory(m, (size_t) sb.st_size)) == NULL) { 68 (void) munmap(m, (size_t) sb.st_size); 69 return (NULL); 70 } 71 72 e->e_flags |= LIBELF_F_MMAP; 73 e->e_fd = fd; 74 e->e_cmd = c; 75 76 if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) { 77 (void) elf_end(e); 78 LIBELF_SET_ERROR(ARGUMENT, 0); 79 return (NULL); 80 } 81 82 return (e); 83} 84 85Elf * 86elf_begin(int fd, Elf_Cmd c, Elf *a) 87{ 88 Elf *e; 89 90 e = NULL; 91 92 if (LIBELF_PRIVATE(version) == EV_NONE) { 93 LIBELF_SET_ERROR(SEQUENCE, 0); 94 return (NULL); 95 } 96 97 switch (c) { 98 case ELF_C_NULL: 99 return (NULL); 100 101 case ELF_C_WRITE: 102 103 if (a != NULL) { /* not allowed for ar(1) archives. */ 104 LIBELF_SET_ERROR(ARGUMENT, 0); 105 return (NULL); 106 } 107 108 /* 109 * Check writeability of `fd' immediately and fail if 110 * not writeable. 111 */ 112 if (ftruncate(fd, (off_t) 0) < 0) { 113 LIBELF_SET_ERROR(IO, errno); 114 return (NULL); 115 } 116 117 if ((e = _libelf_allocate_elf()) != NULL) { 118 _libelf_init_elf(e, ELF_K_ELF); 119 e->e_byteorder = LIBELF_PRIVATE(byteorder); 120 e->e_fd = fd; 121 e->e_cmd = c; 122 } 123 return (e); 124 125 case ELF_C_RDWR: 126 if (a != NULL) { /* not allowed for ar(1) archives. */ 127 LIBELF_SET_ERROR(ARGUMENT, 0); 128 return (NULL); 129 } 130 /*FALLTHROUGH*/ 131 case ELF_C_READ: 132 /* 133 * Descriptor `a' could be for a regular ELF file, or 134 * for an ar(1) archive. If descriptor `a' was opened 135 * using a valid file descriptor, we need to check if 136 * the passed in `fd' value matches the original one. 137 */ 138 if (a && 139 ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) { 140 LIBELF_SET_ERROR(ARGUMENT, 0); 141 return (NULL); 142 } 143 break; 144 145 default: 146 LIBELF_SET_ERROR(ARGUMENT, 0); 147 return (NULL); 148 149 } 150 151 if (a == NULL) 152 e = _libelf_open_object(fd, c); 153 else if (a->e_kind == ELF_K_AR) 154 e = _libelf_ar_open_member(a->e_fd, c, a); 155 else 156 (e = a)->e_activations++; 157 158 return (e); 159} 160