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 (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. 24 */ 25 26 #include <stdio.h> 27 #include <string.h> 28 #include <link.h> 29 #include <debug.h> 30 #include "msg.h" 31 #include "_libld.h" 32 33 /* 34 * Determine whether a (COMDAT) group has already been encountered. If so, 35 * indicate that the group descriptor has an overriding group (gd_oisc). This 36 * indication triggers the ld_place_section() to discard this group, while the 37 * gd_oisc information provides for complete diagnostics of the override. 38 * Otherwise, this is the first occurrence of this group, therefore the group 39 * descriptor is saved for future comparisons. 40 */ 41 static uintptr_t 42 gpavl_loaded(Ofl_desc *ofl, Group_desc *gdp) 43 { 44 Isd_node isd, *isdp; 45 avl_tree_t *avlt; 46 avl_index_t where; 47 48 /* 49 * Create a groups avl tree if required. 50 */ 51 if ((avlt = ofl->ofl_groups) == NULL) { 52 if ((avlt = libld_calloc(sizeof (avl_tree_t), 1)) == NULL) 53 return (S_ERROR); 54 avl_create(avlt, isdavl_compare, sizeof (Isd_node), 55 SGSOFFSETOF(Isd_node, isd_avl)); 56 ofl->ofl_groups = avlt; 57 } 58 59 /* 60 * An SHT_GROUP section is identified by the name of its signature 61 * symbol rather than section name. Although the section names are 62 * often unique, this is not required, and some compilers set it to 63 * a generic name like ".group". 64 */ 65 isd.isd_name = gdp->gd_name; 66 isd.isd_hash = sgs_str_hash(isd.isd_name); 67 68 if ((isdp = avl_find(avlt, &isd, &where)) != NULL) { 69 gdp->gd_oisc = isdp->isd_isp; 70 return (1); 71 } 72 73 /* 74 * This is a new group - so keep it. 75 */ 76 if ((isdp = libld_calloc(sizeof (Isd_node), 1)) == NULL) 77 return (S_ERROR); 78 79 isdp->isd_name = isd.isd_name; 80 isdp->isd_hash = isd.isd_hash; 81 isdp->isd_isp = gdp->gd_isc; 82 83 avl_insert(avlt, isdp, where); 84 return (0); 85 } 86 87 Group_desc * 88 ld_get_group(Ofl_desc *ofl, Is_desc *isp) 89 { 90 Ifl_desc *ifl = isp->is_file; 91 uint_t scnndx = isp->is_scnndx; 92 Group_desc *gdp; 93 Aliste idx; 94 95 /* 96 * Scan the GROUP sections associated with this file to find the 97 * matching group section. 98 */ 99 for (ALIST_TRAVERSE(ifl->ifl_groups, idx, gdp)) { 100 size_t ndx; 101 Word *data; 102 103 if (isp->is_shdr->sh_type == SHT_GROUP) { 104 if (isp->is_scnndx == gdp->gd_isc->is_scnndx) 105 return (gdp); 106 continue; 107 } 108 109 data = gdp->gd_data; 110 for (ndx = 1; ndx < gdp->gd_cnt; ndx++) { 111 if (data[ndx] == scnndx) 112 return (gdp); 113 } 114 } 115 116 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ELF_NOGROUPSECT), 117 ifl->ifl_name, EC_WORD(isp->is_scnndx), isp->is_name); 118 return (NULL); 119 } 120 121 /* 122 * When creating a .debug_macro section, in an attempt to make certain DWARF 123 * macro information shareable, the GNU compiler must construct group sections 124 * with a repeatable signature symbol while nevertheless having no actual 125 * symbol to refer to (because it relates to macros). 126 * 127 * We use this as yet another way to clue ourselves in that sloppy relocation 128 * will likely be required. 129 * 130 * The format of these gensym'd names is: 131 * wm<offset size>.<encoded path name>.<lineno>.<32byte hash> 132 * Where the encoded file name may be absent. 133 */ 134 static boolean_t 135 is_header_gensym(const char *name) 136 { 137 const char *c = NULL; 138 size_t len = strlen(name); 139 140 /* No room for leader, hash, and periods */ 141 if (len < 37) 142 return (B_FALSE); 143 144 if ((strncmp(name, "wm4.", 4) != 0) && 145 strncmp(name, "wm8.", 4) != 0) 146 return (B_FALSE); 147 148 c = &name[len - 33]; 149 if (*c++ != '.') 150 return (B_FALSE); 151 152 for (; *c != '\0'; c++) { 153 if (!(((*c >= 'a') && (*c <= 'f')) || 154 ((*c >= '0') && (*c <= '9')))) { 155 return (B_FALSE); 156 } 157 } 158 159 return (B_TRUE); 160 } 161 162 uintptr_t 163 ld_group_process(Is_desc *gisc, Ofl_desc *ofl) 164 { 165 Ifl_desc *gifl = gisc->is_file; 166 Shdr *sshdr, *gshdr = gisc->is_shdr; 167 Is_desc *isc; 168 Sym *sym; 169 const char *str; 170 Group_desc gd; 171 size_t ndx; 172 int gnu_stt_section; 173 174 /* 175 * Confirm that the sh_link points to a valid section. 176 */ 177 if ((gshdr->sh_link == SHN_UNDEF) || 178 (gshdr->sh_link >= gifl->ifl_shnum) || 179 ((isc = gifl->ifl_isdesc[gshdr->sh_link]) == NULL)) { 180 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_FIL_INVSHLINK), 181 gifl->ifl_name, EC_WORD(gisc->is_scnndx), 182 gisc->is_name, EC_XWORD(gshdr->sh_link)); 183 return (0); 184 } 185 if (gshdr->sh_entsize == 0) { 186 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_FIL_INVSHENTSIZE), 187 gifl->ifl_name, EC_WORD(gisc->is_scnndx), gisc->is_name, 188 EC_XWORD(gshdr->sh_entsize)); 189 return (0); 190 } 191 192 /* 193 * Get the associated symbol table. Sanity check the sh_info field 194 * (which points to the signature symbol table entry) against the size 195 * of the symbol table. 196 */ 197 sshdr = isc->is_shdr; 198 sym = (Sym *)isc->is_indata->d_buf; 199 200 if ((sshdr->sh_info == SHN_UNDEF) || 201 (gshdr->sh_info >= (Word)(sshdr->sh_size / sshdr->sh_entsize)) || 202 ((isc = gifl->ifl_isdesc[sshdr->sh_link]) == NULL)) { 203 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_FIL_INVSHINFO), 204 gifl->ifl_name, EC_WORD(gisc->is_scnndx), gisc->is_name, 205 EC_XWORD(gshdr->sh_info)); 206 return (0); 207 } 208 209 sym += gshdr->sh_info; 210 211 /* 212 * Get the symbol name from the associated string table. 213 */ 214 str = (char *)isc->is_indata->d_buf; 215 str += sym->st_name; 216 217 /* 218 * The GNU assembler can use section symbols as the signature symbol 219 * as described by this comment in the gold linker (found via google): 220 * 221 * It seems that some versions of gas will create a section group 222 * associated with a section symbol, and then fail to give a name 223 * to the section symbol. In such a case, use the name of the 224 * section. 225 * 226 * In order to support such objects, we do the same. 227 */ 228 gnu_stt_section = ((sym->st_name == 0) || (*str == '\0')) && 229 (ELF_ST_TYPE(sym->st_info) == STT_SECTION); 230 if (gnu_stt_section) 231 str = gisc->is_name; 232 233 234 /* 235 * Generate a group descriptor. 236 */ 237 gd.gd_isc = gisc; 238 gd.gd_oisc = NULL; 239 gd.gd_name = str; 240 gd.gd_data = gisc->is_indata->d_buf; 241 gd.gd_cnt = gisc->is_indata->d_size / sizeof (Word); 242 243 /* 244 * If the signature symbol is a name generated by the GNU compiler to 245 * refer to a header, we need sloppy relocation. 246 */ 247 if (is_header_gensym(str)) { 248 if ((ofl->ofl_flags1 & FLG_OF1_NRLXREL) == 0) 249 ofl->ofl_flags1 |= FLG_OF1_RLXREL; 250 DBG_CALL(Dbg_sec_gnu_comdat(ofl->ofl_lml, gisc, TRUE, 251 (ofl->ofl_flags1 & FLG_OF1_RLXREL) != 0)); 252 } 253 254 /* 255 * Validate the section indices within the group. If this is a COMDAT 256 * group, mark each section as COMDAT. 257 */ 258 for (ndx = 1; ndx < gd.gd_cnt; ndx++) { 259 Word gndx; 260 261 if ((gndx = gd.gd_data[ndx]) >= gifl->ifl_shnum) { 262 ld_eprintf(ofl, ERR_FATAL, 263 MSG_INTL(MSG_GRP_INVALNDX), gifl->ifl_name, 264 EC_WORD(gisc->is_scnndx), gisc->is_name, ndx, gndx); 265 return (0); 266 } 267 268 if (gd.gd_data[0] & GRP_COMDAT) 269 gifl->ifl_isdesc[gndx]->is_flags |= FLG_IS_COMDAT; 270 } 271 272 /* 273 * If this is a COMDAT group, determine whether this group has already 274 * been encountered, or whether this is the first instance of the group. 275 */ 276 if ((gd.gd_data[0] & GRP_COMDAT) && 277 (gpavl_loaded(ofl, &gd) == S_ERROR)) 278 return (S_ERROR); 279 280 /* 281 * Associate the group descriptor with this input file. 282 */ 283 if (alist_append(&(gifl->ifl_groups), &gd, sizeof (Group_desc), 284 AL_CNT_IFL_GROUPS) == NULL) 285 return (S_ERROR); 286 287 return (1); 288 } 289