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 int resid; 72 int vfslocked; 73 size_t sz; 74 struct nameidata nd; 75 struct thread *td = curthread; 76 uint8_t ctf_hdr[CTF_HDR_SIZE]; 77 #endif 78 int error = 0; 79 80 if (lf == NULL || lc == NULL) 81 return (EINVAL); 82 83 /* Set the defaults for no CTF present. That's not a crime! */ 84 bzero(lc, sizeof(*lc)); 85 86 #ifdef DDB_CTF 87 /* 88 * First check if we've tried to load CTF data previously and the 89 * CTF ELF section wasn't found. We flag that condition by setting 90 * ctfcnt to -1. See below. 91 */ 92 if (ef->ctfcnt < 0) 93 return (0); 94 95 /* Now check if we've already loaded the CTF data.. */ 96 if (ef->ctfcnt > 0) { 97 /* We only need to load once. */ 98 lc->ctftab = ef->ctftab; 99 lc->ctfcnt = ef->ctfcnt; 100 lc->symtab = ef->ddbsymtab; 101 lc->strtab = ef->ddbstrtab; 102 lc->strcnt = ef->ddbstrcnt; 103 lc->nsym = ef->ddbsymcnt; 104 lc->ctfoffp = (uint32_t **) &ef->ctfoff; 105 lc->typoffp = (uint32_t **) &ef->typoff; 106 lc->typlenp = &ef->typlen; 107 return (0); 108 } 109 110 /* 111 * We need to try reading the CTF data. Flag no CTF data present 112 * by default and if we actually succeed in reading it, we'll 113 * update ctfcnt to the number of bytes read. 114 */ 115 ef->ctfcnt = -1; 116 117 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, lf->pathname, td); 118 flags = FREAD; 119 error = vn_open(&nd, &flags, 0, NULL); 120 if (error) 121 return (error); 122 vfslocked = NDHASGIANT(&nd); 123 NDFREE(&nd, NDF_ONLY_PNBUF); 124 125 /* Allocate memory for the FLF header. */ 126 if ((hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK)) == NULL) { 127 error = ENOMEM; 128 goto out; 129 } 130 131 /* Read the ELF header. */ 132 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr), 133 0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, 134 td)) != 0) 135 goto out; 136 137 /* Sanity check. */ 138 if (!IS_ELF(*hdr)) { 139 error = ENOEXEC; 140 goto out; 141 } 142 143 nbytes = hdr->e_shnum * hdr->e_shentsize; 144 if (nbytes == 0 || hdr->e_shoff == 0 || 145 hdr->e_shentsize != sizeof(Elf_Shdr)) { 146 error = ENOEXEC; 147 goto out; 148 } 149 150 /* Allocate memory for all the section headers */ 151 if ((shdr = malloc(nbytes, M_LINKER, M_WAITOK)) == NULL) { 152 error = ENOMEM; 153 goto out; 154 } 155 156 /* Read all the section headers */ 157 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, 158 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 159 &resid, td)) != 0) 160 goto out; 161 162 /* 163 * We need to search for the CTF section by name, so if the 164 * section names aren't present, then we can't locate the 165 * .SUNW_ctf section containing the CTF data. 166 */ 167 if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) 168 goto out; 169 170 /* Allocate memory to buffer the section header strings. */ 171 if ((shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER, 172 M_WAITOK)) == NULL) { 173 error = ENOMEM; 174 goto out; 175 } 176 177 /* Read the section header strings. */ 178 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab, 179 shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset, 180 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, 181 td)) != 0) 182 goto out; 183 184 /* Search for the section containing the CTF data. */ 185 for (i = 0; i < hdr->e_shnum; i++) 186 if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0) 187 break; 188 189 /* Check if the CTF section wasn't found. */ 190 if (i >= hdr->e_shnum) 191 goto out; 192 193 /* Read the CTF header. */ 194 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, ctf_hdr, sizeof(ctf_hdr), 195 shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 196 NOCRED, &resid, td)) != 0) 197 goto out; 198 199 /* Check the CTF magic number. (XXX check for big endian!) */ 200 if (ctf_hdr[0] != 0xf1 || ctf_hdr[1] != 0xcf) 201 goto out; 202 203 /* Check if version 2. */ 204 if (ctf_hdr[2] != 2) 205 goto out; 206 207 /* Check if the data is compressed. */ 208 if ((ctf_hdr[3] & 0x1) != 0) { 209 uint32_t *u32 = (uint32_t *) ctf_hdr; 210 211 /* 212 * The last two fields in the CTF header are the offset 213 * from the end of the header to the start of the string 214 * data and the length of that string data. se this 215 * information to determine the decompressed CTF data 216 * buffer required. 217 */ 218 sz = u32[CTF_HDR_STRTAB_U32] + u32[CTF_HDR_STRLEN_U32] + 219 sizeof(ctf_hdr); 220 221 /* 222 * Allocate memory for the compressed CTF data, including 223 * the header (which isn't compressed). 224 */ 225 if ((raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK)) == NULL) { 226 error = ENOMEM; 227 goto out; 228 } 229 } else { 230 /* 231 * The CTF data is not compressed, so the ELF section 232 * size is the same as the buffer size required. 233 */ 234 sz = shdr[i].sh_size; 235 } 236 237 /* 238 * Allocate memory to buffer the CTF data in it's decompressed 239 * form. 240 */ 241 if ((ctftab = malloc(sz, M_LINKER, M_WAITOK)) == NULL) { 242 error = ENOMEM; 243 goto out; 244 } 245 246 /* 247 * Read the CTF data into the raw buffer if compressed, or 248 * directly into the CTF buffer otherwise. 249 */ 250 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw, 251 shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 252 td->td_ucred, NOCRED, &resid, td)) != 0) 253 goto out; 254 255 /* Check if decompression is required. */ 256 if (raw != NULL) { 257 z_stream zs; 258 int ret; 259 260 /* 261 * The header isn't compressed, so copy that into the 262 * CTF buffer first. 263 */ 264 bcopy(ctf_hdr, ctftab, sizeof(ctf_hdr)); 265 266 /* Initialise the zlib structure. */ 267 bzero(&zs, sizeof(zs)); 268 zs.zalloc = z_alloc; 269 zs.zfree = z_free; 270 271 if (inflateInit(&zs) != Z_OK) { 272 error = EIO; 273 goto out; 274 } 275 276 zs.avail_in = shdr[i].sh_size - sizeof(ctf_hdr); 277 zs.next_in = ((uint8_t *) raw) + sizeof(ctf_hdr); 278 zs.avail_out = sz - sizeof(ctf_hdr); 279 zs.next_out = ((uint8_t *) ctftab) + sizeof(ctf_hdr); 280 if ((ret = inflate(&zs, Z_FINISH)) != 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 VFS_UNLOCK_GIANT(vfslocked); 309 310 if (hdr != NULL) 311 free(hdr, M_LINKER); 312 if (shdr != NULL) 313 free(shdr, M_LINKER); 314 if (shstrtab != NULL) 315 free(shstrtab, M_LINKER); 316 if (ctftab != NULL) 317 free(ctftab, M_LINKER); 318 if (raw != NULL) 319 free(raw, M_LINKER); 320 #else 321 error = EOPNOTSUPP; 322 #endif 323 324 return (error); 325 } 326