1 /* $OpenBSD: library_mquery.c,v 1.41 2012/05/08 14:32:01 jsing Exp $ */ 2 3 /* 4 * Copyright (c) 2002 Dale Rahn 5 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 17 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 */ 29 30 #define _DYN_LOADER 31 32 #include <sys/types.h> 33 #include <sys/param.h> 34 #include <fcntl.h> 35 #include <sys/mman.h> 36 #include "dl_prebind.h" 37 38 #include "syscall.h" 39 #include "archdep.h" 40 #include "resolve.h" 41 #include "sod.h" 42 43 #define PFLAGS(X) ((((X) & PF_R) ? PROT_READ : 0) | \ 44 (((X) & PF_W) ? PROT_WRITE : 0) | \ 45 (((X) & PF_X) ? PROT_EXEC : 0)) 46 47 void 48 _dl_load_list_free(struct load_list *load_list) 49 { 50 struct load_list *next; 51 Elf_Addr align = _dl_pagesz - 1; 52 53 while (load_list != NULL) { 54 if (load_list->start != NULL) 55 _dl_munmap(load_list->start, 56 ((load_list->size) + align) & ~align); 57 next = load_list->next; 58 _dl_free(load_list); 59 load_list = next; 60 } 61 } 62 63 64 void 65 _dl_unload_shlib(elf_object_t *object) 66 { 67 struct dep_node *n; 68 69 DL_DEB(("unload_shlib called on %s\n", object->load_name)); 70 if (OBJECT_REF_CNT(object) == 0 && 71 (object->status & STAT_UNLOADED) == 0) { 72 object->status |= STAT_UNLOADED; 73 TAILQ_FOREACH(n, &object->child_list, next_sib) 74 _dl_unload_shlib(n->data); 75 TAILQ_FOREACH(n, &object->grpref_list, next_sib) 76 _dl_unload_shlib(n->data); 77 DL_DEB(("unload_shlib unloading on %s\n", object->load_name)); 78 _dl_load_list_free(object->load_list); 79 _dl_remove_object(object); 80 } 81 } 82 83 84 elf_object_t * 85 _dl_tryload_shlib(const char *libname, int type, int flags) 86 { 87 int libfile, i; 88 struct load_list *ld, *lowld = NULL; 89 elf_object_t *object; 90 Elf_Dyn *dynp = 0; 91 Elf_Ehdr *ehdr; 92 Elf_Phdr *phdp; 93 Elf_Addr load_end = 0; 94 Elf_Addr align = _dl_pagesz - 1, off, size; 95 struct stat sb; 96 void *prebind_data; 97 char hbuf[4096]; 98 99 #define ROUND_PG(x) (((x) + align) & ~(align)) 100 #define TRUNC_PG(x) ((x) & ~(align)) 101 102 libfile = _dl_open(libname, O_RDONLY); 103 if (libfile < 0) { 104 _dl_errno = DL_CANT_OPEN; 105 return(0); 106 } 107 108 if ( _dl_fstat(libfile, &sb) < 0) { 109 _dl_errno = DL_CANT_OPEN; 110 return(0); 111 } 112 113 for (object = _dl_objects; object != NULL; object = object->next) { 114 if (object->dev == sb.st_dev && 115 object->inode == sb.st_ino) { 116 object->obj_flags |= flags & DF_1_GLOBAL; 117 _dl_close(libfile); 118 if (_dl_loading_object == NULL) 119 _dl_loading_object = object; 120 if (object->load_object != _dl_objects && 121 object->load_object != _dl_loading_object) { 122 _dl_link_grpref(object->load_object, 123 _dl_loading_object); 124 } 125 return(object); 126 } 127 } 128 129 _dl_read(libfile, hbuf, sizeof(hbuf)); 130 ehdr = (Elf_Ehdr *)hbuf; 131 if (ehdr->e_ident[0] != ELFMAG0 || ehdr->e_ident[1] != ELFMAG1 || 132 ehdr->e_ident[2] != ELFMAG2 || ehdr->e_ident[3] != ELFMAG3 || 133 ehdr->e_type != ET_DYN || ehdr->e_machine != MACHID) { 134 _dl_close(libfile); 135 _dl_errno = DL_NOT_ELF; 136 return(0); 137 } 138 139 /* Insertion sort */ 140 #define LDLIST_INSERT(ld) do { \ 141 struct load_list **_ld; \ 142 for (_ld = &lowld; *_ld != NULL; _ld = &(*_ld)->next) \ 143 if ((*_ld)->moff > ld->moff) \ 144 break; \ 145 ld->next = *_ld; \ 146 *_ld = ld; \ 147 } while (0) 148 /* 149 * Alright, we might have a winner! 150 * Figure out how much VM space we need and set up the load 151 * list that we'll use to find free VM space. 152 */ 153 phdp = (Elf_Phdr *)(hbuf + ehdr->e_phoff); 154 for (i = 0; i < ehdr->e_phnum; i++, phdp++) { 155 switch (phdp->p_type) { 156 case PT_LOAD: 157 off = (phdp->p_vaddr & align); 158 size = off + phdp->p_filesz; 159 160 if (size != 0) { 161 ld = _dl_malloc(sizeof(struct load_list)); 162 ld->start = NULL; 163 ld->size = size; 164 ld->moff = TRUNC_PG(phdp->p_vaddr); 165 ld->foff = TRUNC_PG(phdp->p_offset); 166 ld->prot = PFLAGS(phdp->p_flags); 167 LDLIST_INSERT(ld); 168 } 169 170 if ((PFLAGS(phdp->p_flags) & PROT_WRITE) == 0 || 171 ROUND_PG(size) == ROUND_PG(off + phdp->p_memsz)) 172 break; 173 /* This phdr has a zfod section */ 174 ld = _dl_malloc(sizeof(struct load_list)); 175 ld->start = NULL; 176 ld->size = ROUND_PG(off + phdp->p_memsz) - 177 ROUND_PG(size); 178 ld->moff = TRUNC_PG(phdp->p_vaddr) + 179 ROUND_PG(size); 180 ld->foff = -1; 181 ld->prot = PFLAGS(phdp->p_flags); 182 LDLIST_INSERT(ld); 183 break; 184 case PT_DYNAMIC: 185 dynp = (Elf_Dyn *)phdp->p_vaddr; 186 break; 187 case PT_TLS: 188 _dl_printf("%s: unsupported TLS program header in %s\n", 189 _dl_progname, libname); 190 _dl_close(libfile); 191 _dl_errno = DL_CANT_LOAD_OBJ; 192 return(0); 193 default: 194 break; 195 } 196 } 197 198 #define LOFF ((Elf_Addr)lowld->start - lowld->moff) 199 200 retry: 201 for (ld = lowld; ld != NULL; ld = ld->next) { 202 off_t foff; 203 int fd, flags; 204 205 /* 206 * We don't want to provide the fd/off hint for anything 207 * but the first mapping, all other might have 208 * cache-incoherent aliases and will cause this code to 209 * loop forever. 210 */ 211 if (ld == lowld) { 212 fd = libfile; 213 foff = ld->foff; 214 flags = 0; 215 } else { 216 fd = -1; 217 foff = 0; 218 flags = MAP_FIXED; 219 } 220 221 ld->start = (void *)(LOFF + ld->moff); 222 223 /* 224 * Magic here. 225 * The first mquery is done with MAP_FIXED to see if 226 * the mapping we want is free. If it's not, we redo the 227 * mquery without MAP_FIXED to get the next free mapping, 228 * adjust the base mapping address to match this free mapping 229 * and restart the process again. 230 */ 231 ld->start = _dl_mquery(ld->start, ROUND_PG(ld->size), ld->prot, 232 flags, fd, foff); 233 if (_dl_mmap_error(ld->start)) { 234 ld->start = (void *)(LOFF + ld->moff); 235 ld->start = _dl_mquery(ld->start, ROUND_PG(ld->size), 236 ld->prot, flags & ~MAP_FIXED, fd, foff); 237 if (_dl_mmap_error(ld->start)) 238 goto fail; 239 } 240 241 if (ld->start != (void *)(LOFF + ld->moff)) { 242 lowld->start = ld->start - ld->moff + lowld->moff; 243 goto retry; 244 } 245 /* 246 * XXX - we need some kind of boundary condition here, 247 * or fix mquery to not run into the stack 248 */ 249 } 250 251 for (ld = lowld; ld != NULL; ld = ld->next) { 252 int fd, flags; 253 off_t foff; 254 void *res; 255 256 if (ld->foff < 0) { 257 fd = -1; 258 foff = 0; 259 flags = MAP_FIXED|MAP_PRIVATE|MAP_ANON; 260 } else { 261 fd = libfile; 262 foff = ld->foff; 263 flags = MAP_FIXED|MAP_PRIVATE; 264 } 265 res = _dl_mmap(ld->start, ROUND_PG(ld->size), ld->prot, flags, 266 fd, foff); 267 if (_dl_mmap_error(res)) 268 goto fail; 269 /* Zero out everything past the EOF */ 270 if ((ld->prot & PROT_WRITE) != 0 && (ld->size & align) != 0) 271 _dl_memset((char *)ld->start + ld->size, 0, 272 _dl_pagesz - (ld->size & align)); 273 load_end = (Elf_Addr)ld->start + ROUND_PG(ld->size); 274 } 275 276 prebind_data = prebind_load_fd(libfile, libname); 277 278 _dl_close(libfile); 279 280 dynp = (Elf_Dyn *)((unsigned long)dynp + LOFF); 281 object = _dl_finalize_object(libname, dynp, 282 (Elf_Phdr *)((char *)lowld->start + ehdr->e_phoff), ehdr->e_phnum, 283 type, (Elf_Addr)lowld->start, LOFF); 284 if (object) { 285 object->prebind_data = prebind_data; 286 object->load_size = (Elf_Addr)load_end - (Elf_Addr)lowld->start; 287 object->load_list = lowld; 288 /* set inode, dev from stat info */ 289 object->dev = sb.st_dev; 290 object->inode = sb.st_ino; 291 object->obj_flags |= flags; 292 _dl_build_sod(object->load_name, &object->sod); 293 } else { 294 /* XXX no point. object is never returned NULL */ 295 _dl_load_list_free(lowld); 296 } 297 return(object); 298 fail: 299 _dl_printf("%s: rtld mmap failed mapping %s.\n", 300 _dl_progname, libname); 301 _dl_close(libfile); 302 _dl_errno = DL_CANT_MMAP; 303 _dl_load_list_free(lowld); 304 return(0); 305 } 306