1 /*- 2 * Copyright (c) 2008 John Birrell <jb@freebsd.org> 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 * $FreeBSD$ 27 */ 28 29 /* 30 * Note this file is included by both link_elf.c and link_elf_obj.c. 31 * 32 * The CTF header structure definition can't be used here because it's 33 * (annoyingly) covered by the CDDL. We will just use a few bytes from 34 * it as an integer array where we 'know' what they mean. 35 */ 36 #define CTF_HDR_SIZE 36 37 #define CTF_HDR_STRTAB_U32 7 38 #define CTF_HDR_STRLEN_U32 8 39 40 #ifdef DDB_CTF 41 static void * 42 z_alloc(void *nil, u_int items, u_int size) 43 { 44 void *ptr; 45 46 ptr = malloc(items * size, M_TEMP, M_NOWAIT); 47 return ptr; 48 } 49 50 static void 51 z_free(void *nil, void *ptr) 52 { 53 free(ptr, M_TEMP); 54 } 55 56 #endif 57 58 static int 59 link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc) 60 { 61 #ifdef DDB_CTF 62 Elf_Ehdr *hdr = NULL; 63 Elf_Shdr *shdr = NULL; 64 caddr_t ctftab = NULL; 65 caddr_t raw = NULL; 66 caddr_t shstrtab = NULL; 67 elf_file_t ef = (elf_file_t) lf; 68 int flags; 69 int i; 70 int nbytes; 71 size_t sz; 72 struct nameidata nd; 73 struct thread *td = curthread; 74 uint8_t ctf_hdr[CTF_HDR_SIZE]; 75 #endif 76 int error = 0; 77 78 if (lf == NULL || lc == NULL) 79 return (EINVAL); 80 81 /* Set the defaults for no CTF present. That's not a crime! */ 82 bzero(lc, sizeof(*lc)); 83 84 #ifdef DDB_CTF 85 /* 86 * First check if we've tried to load CTF data previously and the 87 * CTF ELF section wasn't found. We flag that condition by setting 88 * ctfcnt to -1. See below. 89 */ 90 if (ef->ctfcnt < 0) 91 return (EFTYPE); 92 93 /* Now check if we've already loaded the CTF data.. */ 94 if (ef->ctfcnt > 0) { 95 /* We only need to load once. */ 96 lc->ctftab = ef->ctftab; 97 lc->ctfcnt = ef->ctfcnt; 98 lc->symtab = ef->ddbsymtab; 99 lc->strtab = ef->ddbstrtab; 100 lc->strcnt = ef->ddbstrcnt; 101 lc->nsym = ef->ddbsymcnt; 102 lc->ctfoffp = (uint32_t **) &ef->ctfoff; 103 lc->typoffp = (uint32_t **) &ef->typoff; 104 lc->typlenp = &ef->typlen; 105 return (0); 106 } 107 108 /* 109 * We need to try reading the CTF data. Flag no CTF data present 110 * by default and if we actually succeed in reading it, we'll 111 * update ctfcnt to the number of bytes read. 112 */ 113 ef->ctfcnt = -1; 114 115 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, lf->pathname, td); 116 flags = FREAD; 117 error = vn_open(&nd, &flags, 0, NULL); 118 if (error) 119 return (error); 120 NDFREE(&nd, NDF_ONLY_PNBUF); 121 122 /* Allocate memory for the FLF header. */ 123 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 124 125 /* Read the ELF header. */ 126 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr), 127 0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL, 128 td)) != 0) 129 goto out; 130 131 /* Sanity check. */ 132 if (!IS_ELF(*hdr)) { 133 error = ENOEXEC; 134 goto out; 135 } 136 137 nbytes = hdr->e_shnum * hdr->e_shentsize; 138 if (nbytes == 0 || hdr->e_shoff == 0 || 139 hdr->e_shentsize != sizeof(Elf_Shdr)) { 140 error = ENOEXEC; 141 goto out; 142 } 143 144 /* Allocate memory for all the section headers */ 145 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 146 147 /* Read all the section headers */ 148 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, 149 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 150 NULL, td)) != 0) 151 goto out; 152 153 /* 154 * We need to search for the CTF section by name, so if the 155 * section names aren't present, then we can't locate the 156 * .SUNW_ctf section containing the CTF data. 157 */ 158 if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 159 printf("%s(%d): module %s e_shstrndx is %d, sh_type is %d\n", 160 __func__, __LINE__, lf->pathname, hdr->e_shstrndx, 161 shdr[hdr->e_shstrndx].sh_type); 162 error = EFTYPE; 163 goto out; 164 } 165 166 /* Allocate memory to buffer the section header strings. */ 167 shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER, M_WAITOK); 168 169 /* Read the section header strings. */ 170 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab, 171 shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset, 172 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL, td)) != 0) 173 goto out; 174 175 /* Search for the section containing the CTF data. */ 176 for (i = 0; i < hdr->e_shnum; i++) 177 if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0) 178 break; 179 180 /* Check if the CTF section wasn't found. */ 181 if (i >= hdr->e_shnum) { 182 printf("%s(%d): module %s has no .SUNW_ctf section\n", 183 __func__, __LINE__, lf->pathname); 184 error = EFTYPE; 185 goto out; 186 } 187 188 /* Read the CTF header. */ 189 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, ctf_hdr, sizeof(ctf_hdr), 190 shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 191 NOCRED, NULL, td)) != 0) 192 goto out; 193 194 /* Check the CTF magic number. (XXX check for big endian!) */ 195 if (ctf_hdr[0] != 0xf1 || ctf_hdr[1] != 0xcf) { 196 printf("%s(%d): module %s has invalid format\n", 197 __func__, __LINE__, lf->pathname); 198 error = EFTYPE; 199 goto out; 200 } 201 202 /* Check if version 2. */ 203 if (ctf_hdr[2] != 2) { 204 printf("%s(%d): module %s CTF format version is %d " 205 "(2 expected)\n", 206 __func__, __LINE__, lf->pathname, ctf_hdr[2]); 207 error = EFTYPE; 208 goto out; 209 } 210 211 /* Check if the data is compressed. */ 212 if ((ctf_hdr[3] & 0x1) != 0) { 213 uint32_t *u32 = (uint32_t *) ctf_hdr; 214 215 /* 216 * The last two fields in the CTF header are the offset 217 * from the end of the header to the start of the string 218 * data and the length of that string data. se this 219 * information to determine the decompressed CTF data 220 * buffer required. 221 */ 222 sz = u32[CTF_HDR_STRTAB_U32] + u32[CTF_HDR_STRLEN_U32] + 223 sizeof(ctf_hdr); 224 225 /* 226 * Allocate memory for the compressed CTF data, including 227 * the header (which isn't compressed). 228 */ 229 raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK); 230 } else { 231 /* 232 * The CTF data is not compressed, so the ELF section 233 * size is the same as the buffer size required. 234 */ 235 sz = shdr[i].sh_size; 236 } 237 238 /* 239 * Allocate memory to buffer the CTF data in it's decompressed 240 * form. 241 */ 242 ctftab = malloc(sz, M_LINKER, M_WAITOK); 243 244 /* 245 * Read the CTF data into the raw buffer if compressed, or 246 * directly into the CTF buffer otherwise. 247 */ 248 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw, 249 shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 250 td->td_ucred, NOCRED, NULL, td)) != 0) 251 goto out; 252 253 /* Check if decompression is required. */ 254 if (raw != NULL) { 255 z_stream zs; 256 int ret; 257 258 /* 259 * The header isn't compressed, so copy that into the 260 * CTF buffer first. 261 */ 262 bcopy(ctf_hdr, ctftab, sizeof(ctf_hdr)); 263 264 /* Initialise the zlib structure. */ 265 bzero(&zs, sizeof(zs)); 266 zs.zalloc = z_alloc; 267 zs.zfree = z_free; 268 269 if (inflateInit(&zs) != Z_OK) { 270 error = EIO; 271 goto out; 272 } 273 274 zs.avail_in = shdr[i].sh_size - sizeof(ctf_hdr); 275 zs.next_in = ((uint8_t *) raw) + sizeof(ctf_hdr); 276 zs.avail_out = sz - sizeof(ctf_hdr); 277 zs.next_out = ((uint8_t *) ctftab) + sizeof(ctf_hdr); 278 ret = inflate(&zs, Z_FINISH); 279 inflateEnd(&zs); 280 if (ret != Z_STREAM_END) { 281 printf("%s(%d): zlib inflate returned %d\n", __func__, __LINE__, ret); 282 error = EIO; 283 goto out; 284 } 285 } 286 287 /* Got the CTF data! */ 288 ef->ctftab = ctftab; 289 ef->ctfcnt = shdr[i].sh_size; 290 291 /* We'll retain the memory allocated for the CTF data. */ 292 ctftab = NULL; 293 294 /* Let the caller use the CTF data read. */ 295 lc->ctftab = ef->ctftab; 296 lc->ctfcnt = ef->ctfcnt; 297 lc->symtab = ef->ddbsymtab; 298 lc->strtab = ef->ddbstrtab; 299 lc->strcnt = ef->ddbstrcnt; 300 lc->nsym = ef->ddbsymcnt; 301 lc->ctfoffp = (uint32_t **) &ef->ctfoff; 302 lc->typoffp = (uint32_t **) &ef->typoff; 303 lc->typlenp = &ef->typlen; 304 305 out: 306 VOP_UNLOCK(nd.ni_vp, 0); 307 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 308 309 if (hdr != NULL) 310 free(hdr, M_LINKER); 311 if (shdr != NULL) 312 free(shdr, M_LINKER); 313 if (shstrtab != NULL) 314 free(shstrtab, M_LINKER); 315 if (ctftab != NULL) 316 free(ctftab, M_LINKER); 317 if (raw != NULL) 318 free(raw, M_LINKER); 319 #else 320 error = EOPNOTSUPP; 321 #endif 322 323 return (error); 324 } 325