1 /* Create new section in output file. 2 Copyright (C) 2002-2011 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Written by Ulrich Drepper <drepper (at) redhat.com>, 2002. 5 6 Red Hat elfutils is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by the 8 Free Software Foundation; version 2 of the License. 9 10 Red Hat elfutils is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 General Public License for more details. 14 15 You should have received a copy of the GNU General Public License along 16 with Red Hat elfutils; if not, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 18 19 Red Hat elfutils is an included package of the Open Invention Network. 20 An included package of the Open Invention Network is a package for which 21 Open Invention Network licensees cross-license their patents. No patent 22 license is granted, either expressly or impliedly, by designation as an 23 included package. Should you wish to participate in the Open Invention 24 Network licensing program, please visit www.openinventionnetwork.com 25 <http://www.openinventionnetwork.com>. */ 26 27 #ifdef HAVE_CONFIG_H 28 # include <config.h> 29 #endif 30 31 #include <assert.h> 32 #include <error.h> 33 #include <libintl.h> 34 #include <stdlib.h> 35 #include <string.h> 36 37 #include <libasmP.h> 38 #include <libelf.h> 39 #include <system.h> 40 41 42 /* Memory for the default pattern. The type uses a flexible array 43 which does work well with a static initializer. So we play some 44 dirty tricks here. */ 45 static const struct 46 { 47 struct FillPattern pattern; 48 char zero; 49 } xdefault_pattern = 50 { 51 .pattern = 52 { 53 .len = 1 54 }, 55 .zero = '\0' 56 }; 57 const struct FillPattern *__libasm_default_pattern = &xdefault_pattern.pattern; 58 59 60 static AsmScn_t * 61 text_newscn (AsmScn_t *result, GElf_Word type, GElf_Xword flags) 62 { 63 /* Buffer where we construct the flag string. */ 64 char flagstr[sizeof (GElf_Xword) * 8 + 5]; 65 char *wp = flagstr; 66 const char *typestr = ""; 67 68 /* Only write out the flag string if this is the first time the 69 section is selected. Some assemblers cannot cope with the 70 .section pseudo-op otherwise. */ 71 wp = stpcpy (wp, ", \""); 72 73 if (flags & SHF_WRITE) 74 *wp++ = 'w'; 75 if (flags & SHF_ALLOC) 76 *wp++ = 'a'; 77 if (flags & SHF_EXECINSTR) 78 *wp++ = 'x'; 79 if (flags & SHF_MERGE) 80 *wp++ = 'M'; 81 if (flags & SHF_STRINGS) 82 *wp++ = 'S'; 83 if (flags & SHF_LINK_ORDER) 84 *wp++ = 'L'; 85 86 *wp++ = '"'; 87 88 if (type == SHT_PROGBITS) 89 typestr = ",@progbits"; 90 else if (type == SHT_NOBITS) 91 typestr = ",@nobits"; 92 93 /* Terminate the string. */ 94 *wp = '\0'; 95 96 fprintf (result->ctx->out.file, "\t.section \"%s\"%s%s\n", 97 result->name, flagstr, typestr); 98 99 return result; 100 } 101 102 103 static AsmScn_t * 104 binary_newscn (AsmScn_t *result, GElf_Word type, GElf_Xword flags, 105 size_t scnname_len) 106 { 107 GElf_Shdr shdr_mem; 108 GElf_Shdr *shdr; 109 Elf_Scn *scn; 110 111 /* The initial subsection has the number zero. */ 112 result->subsection_id = 0; 113 114 /* We start at offset zero. */ 115 result->offset = 0; 116 /* And generic alignment. */ 117 result->max_align = 1; 118 119 /* No output yet. */ 120 result->content = NULL; 121 122 /* Put the default fill pattern in place. */ 123 result->pattern = (struct FillPattern *) __libasm_default_pattern; 124 125 /* There are no subsections so far. */ 126 result->subnext = NULL; 127 128 /* Add the name to the section header string table. */ 129 result->data.main.strent = ebl_strtabadd (result->ctx->section_strtab, 130 result->name, scnname_len); 131 assert (result->data.main.strent != NULL); 132 133 /* Create the new ELF section. */ 134 result->data.main.scn = scn = elf_newscn (result->ctx->out.elf); 135 if (scn == NULL) 136 { 137 free (result); 138 __libasm_seterrno (ASM_E_LIBELF); 139 return NULL; 140 } 141 142 /* Not part of a section group (yet). */ 143 result->data.main.next_in_group = NULL; 144 145 /* Remember the flags. */ 146 shdr = gelf_getshdr (scn, &shdr_mem); 147 148 shdr->sh_flags = flags; 149 result->type = shdr->sh_type = type; 150 151 (void) gelf_update_shdr (scn, shdr); 152 153 return result; 154 } 155 156 157 AsmScn_t * 158 asm_newscn (ctx, scnname, type, flags) 159 AsmCtx_t *ctx; 160 const char *scnname; 161 GElf_Word type; 162 GElf_Xword flags; 163 { 164 size_t scnname_len = strlen (scnname) + 1; 165 AsmScn_t *result; 166 167 /* If no context is given there might be an earlier error. */ 168 if (ctx == NULL) 169 return NULL; 170 171 /* Check whether only flags are set which areselectable by the user. */ 172 if (unlikely ((flags & ~(SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR | SHF_MERGE 173 | SHF_STRINGS | SHF_LINK_ORDER)) != 0) 174 /* We allow only two section types: data and data without file 175 representation. */ 176 || (type != SHT_PROGBITS && unlikely (type != SHT_NOBITS))) 177 { 178 __libasm_seterrno (ASM_E_INVALID); 179 return NULL; 180 } 181 182 rwlock_wrlock (ctx->lock); 183 184 /* This is a new section. */ 185 result = (AsmScn_t *) malloc (sizeof (AsmScn_t) + scnname_len); 186 if (result != NULL) 187 { 188 /* Add the name. */ 189 memcpy (result->name, scnname, scnname_len); 190 191 /* Add the reference to the context. */ 192 result->ctx = ctx; 193 194 /* Perform operations according to output mode. */ 195 result = (unlikely (ctx->textp) 196 ? text_newscn (result, type, flags) 197 : binary_newscn (result, type, flags, scnname_len)); 198 199 /* If everything went well finally add the new section to the hash 200 table. */ 201 if (result != NULL) 202 { 203 result->allnext = ctx->section_list; 204 ctx->section_list = result; 205 } 206 } 207 208 rwlock_unlock (ctx->lock); 209 210 return result; 211 } 212 INTDEF(asm_newscn) 213
