1 /* Create descriptor for assembling. 2 Copyright (C) 2002 Red Hat, Inc. 3 This file is part of elfutils. 4 Written by Ulrich Drepper <drepper (at) redhat.com>, 2002. 5 6 This file is free software; you can redistribute it and/or modify 7 it under the terms of either 8 9 * the GNU Lesser General Public License as published by the Free 10 Software Foundation; either version 3 of the License, or (at 11 your option) any later version 12 13 or 14 15 * the GNU General Public License as published by the Free 16 Software Foundation; either version 2 of the License, or (at 17 your option) any later version 18 19 or both in parallel, as here. 20 21 elfutils is distributed in the hope that it will be useful, but 22 WITHOUT ANY WARRANTY; without even the implied warranty of 23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 24 General Public License for more details. 25 26 You should have received copies of the GNU General Public License and 27 the GNU Lesser General Public License along with this program. If 28 not, see <http://www.gnu.org/licenses/>. */ 29 30 #ifdef HAVE_CONFIG_H 31 # include <config.h> 32 #endif 33 34 #include <assert.h> 35 #include <errno.h> 36 #include <stdio.h> 37 #include <stdio_ext.h> 38 #include <stdlib.h> 39 #include <string.h> 40 #include <unistd.h> 41 42 #include <gelf.h> 43 #include "libasmP.h" 44 #include <system.h> 45 46 47 static AsmCtx_t * 48 prepare_text_output (AsmCtx_t *result) 49 { 50 if (result->fd == -1) 51 result->out.file = stdout; 52 else 53 { 54 result->out.file = fdopen (result->fd, "a"); 55 if (result->out.file == NULL) 56 { 57 close (result->fd); 58 free (result); 59 result = NULL; 60 } 61 62 __fsetlocking (result->out.file, FSETLOCKING_BYCALLER); 63 } 64 65 return result; 66 } 67 68 69 static AsmCtx_t * 70 prepare_binary_output (AsmCtx_t *result, Ebl *ebl) 71 { 72 GElf_Ehdr *ehdr; 73 GElf_Ehdr ehdr_mem; 74 75 /* Create the ELF descriptor for the file. */ 76 result->out.elf = elf_begin (result->fd, ELF_C_WRITE_MMAP, NULL); 77 if (result->out.elf == NULL) 78 { 79 err_libelf: 80 unlink (result->tmp_fname); 81 close (result->fd); 82 free (result); 83 __libasm_seterrno (ASM_E_LIBELF); 84 return NULL; 85 } 86 87 /* Create the ELF header for the output file. */ 88 int class = ebl_get_elfclass (ebl); 89 if (gelf_newehdr (result->out.elf, class) == 0) 90 goto err_libelf; 91 92 ehdr = gelf_getehdr (result->out.elf, &ehdr_mem); 93 /* If this failed we are in trouble. */ 94 assert (ehdr != NULL); 95 96 /* We create an object file. */ 97 ehdr->e_type = ET_REL; 98 /* Set the ELF version. */ 99 ehdr->e_version = EV_CURRENT; 100 101 /* Use the machine, class, and endianess values from the Ebl descriptor. */ 102 ehdr->e_machine = ebl_get_elfmachine (ebl); 103 ehdr->e_ident[EI_CLASS] = class; 104 ehdr->e_ident[EI_DATA] = ebl_get_elfdata (ebl); 105 106 memcpy (&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG); 107 108 /* Write the ELF header information back. */ 109 (void) gelf_update_ehdr (result->out.elf, ehdr); 110 111 /* No section so far. */ 112 result->section_list = NULL; 113 114 /* Initialize the hash table. */ 115 asm_symbol_tab_init (&result->symbol_tab, 67); 116 result->nsymbol_tab = 0; 117 /* And the string tables. */ 118 result->section_strtab = ebl_strtabinit (true); 119 result->symbol_strtab = ebl_strtabinit (true); 120 121 /* We have no section groups so far. */ 122 result->groups = NULL; 123 result->ngroups = 0; 124 125 return result; 126 } 127 128 129 AsmCtx_t * 130 asm_begin (const char *fname, Ebl *ebl, bool textp) 131 { 132 if (fname == NULL && ! textp) 133 return NULL; 134 135 size_t fname_len = fname != NULL ? strlen (fname) : 0; 136 137 /* Create the file descriptor. We do not generate the output file 138 right away. Instead we create a temporary file in the same 139 directory which, if everything goes alright, will replace a 140 possibly existing file with the given name. */ 141 AsmCtx_t *result 142 = (AsmCtx_t *) malloc (sizeof (AsmCtx_t) + 2 * fname_len + 9); 143 if (result == NULL) 144 return NULL; 145 146 /* Initialize the lock. */ 147 rwlock_init (result->lock); 148 149 if (fname != NULL) 150 { 151 /* Create the name of the temporary file. */ 152 result->fname = stpcpy (mempcpy (result->tmp_fname, fname, fname_len), 153 ".XXXXXX") + 1; 154 memcpy (result->fname, fname, fname_len + 1); 155 156 /* Create the temporary file. */ 157 result->fd = mkstemp (result->tmp_fname); 158 if (result->fd == -1) 159 { 160 int save_errno = errno; 161 free (result); 162 __libasm_seterrno (ASM_E_CANNOT_CREATE); 163 errno = save_errno; 164 return NULL; 165 } 166 } 167 else 168 result->fd = -1; 169 170 /* Initialize the counter for temporary symbols. */ 171 result->tempsym_count = 0; 172 173 /* Now we differentiate between textual and binary output. */ 174 result->textp = textp; 175 if (textp) 176 result = prepare_text_output (result); 177 else 178 result = prepare_binary_output (result, ebl); 179 180 return result; 181 } 182
