1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2008 John Birrell <jb@freebsd.org> 5 * All rights reserved. 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 AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY 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 #include <sys/ctf.h> 30 31 /* 32 * Note this file is included by both link_elf.c and link_elf_obj.c. 33 */ 34 35 #ifdef DDB_CTF 36 #include <contrib/zlib/zlib.h> 37 #endif 38 39 static int 40 link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc) 41 { 42 #ifdef DDB_CTF 43 Elf_Ehdr *hdr = NULL; 44 Elf_Shdr *shdr = NULL; 45 caddr_t ctftab = NULL; 46 caddr_t raw = NULL; 47 caddr_t shstrtab = NULL; 48 elf_file_t ef = (elf_file_t) lf; 49 int flags; 50 int i; 51 int nbytes; 52 size_t sz; 53 struct nameidata nd; 54 struct thread *td = curthread; 55 struct ctf_header cth; 56 #endif 57 int error = 0; 58 59 if (lf == NULL || lc == NULL) 60 return (EINVAL); 61 62 /* Set the defaults for no CTF present. That's not a crime! */ 63 bzero(lc, sizeof(*lc)); 64 65 #ifdef DDB_CTF 66 /* 67 * First check if we've tried to load CTF data previously and the 68 * CTF ELF section wasn't found. We flag that condition by setting 69 * ctfcnt to -1. See below. 70 */ 71 if (ef->ctfcnt < 0) 72 return (EFTYPE); 73 74 /* Now check if we've already loaded the CTF data.. */ 75 if (ef->ctfcnt > 0) { 76 /* We only need to load once. */ 77 lc->ctftab = ef->ctftab; 78 lc->ctfcnt = ef->ctfcnt; 79 lc->symtab = ef->ddbsymtab; 80 lc->strtab = ef->ddbstrtab; 81 lc->strcnt = ef->ddbstrcnt; 82 lc->nsym = ef->ddbsymcnt; 83 lc->ctfoffp = (uint32_t **) &ef->ctfoff; 84 lc->typoffp = (uint32_t **) &ef->typoff; 85 lc->typlenp = &ef->typlen; 86 return (0); 87 } 88 89 /* 90 * We need to try reading the CTF data. Flag no CTF data present 91 * by default and if we actually succeed in reading it, we'll 92 * update ctfcnt to the number of bytes read. 93 */ 94 ef->ctfcnt = -1; 95 96 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, lf->pathname); 97 flags = FREAD; 98 error = vn_open(&nd, &flags, 0, NULL); 99 if (error) 100 return (error); 101 NDFREE_PNBUF(&nd); 102 103 /* Allocate memory for the FLF header. */ 104 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 105 106 /* Read the ELF header. */ 107 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr), 108 0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL, 109 td)) != 0) 110 goto out; 111 112 /* Sanity check. */ 113 if (!IS_ELF(*hdr)) { 114 error = ENOEXEC; 115 goto out; 116 } 117 118 nbytes = hdr->e_shnum * hdr->e_shentsize; 119 if (nbytes == 0 || hdr->e_shoff == 0 || 120 hdr->e_shentsize != sizeof(Elf_Shdr)) { 121 error = ENOEXEC; 122 goto out; 123 } 124 125 /* Allocate memory for all the section headers */ 126 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 127 128 /* Read all the section headers */ 129 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, 130 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 131 NULL, td)) != 0) 132 goto out; 133 134 /* 135 * We need to search for the CTF section by name, so if the 136 * section names aren't present, then we can't locate the 137 * .SUNW_ctf section containing the CTF data. 138 */ 139 if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { 140 printf("%s(%d): module %s e_shstrndx is %d, sh_type is %d\n", 141 __func__, __LINE__, lf->pathname, hdr->e_shstrndx, 142 shdr[hdr->e_shstrndx].sh_type); 143 error = EFTYPE; 144 goto out; 145 } 146 147 /* Allocate memory to buffer the section header strings. */ 148 shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER, M_WAITOK); 149 150 /* Read the section header strings. */ 151 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab, 152 shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset, 153 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL, td)) != 0) 154 goto out; 155 156 /* Search for the section containing the CTF data. */ 157 for (i = 0; i < hdr->e_shnum; i++) 158 if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0) 159 break; 160 161 /* Check if the CTF section wasn't found. */ 162 if (i >= hdr->e_shnum) { 163 printf("%s(%d): module %s has no .SUNW_ctf section\n", 164 __func__, __LINE__, lf->pathname); 165 error = EFTYPE; 166 goto out; 167 } 168 169 /* Read the CTF header. */ 170 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, &cth, sizeof(cth), 171 shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 172 NOCRED, NULL, td)) != 0) 173 goto out; 174 175 /* Check the CTF magic number. */ 176 if (cth.cth_magic != CTF_MAGIC) { 177 printf("%s(%d): module %s has invalid format\n", 178 __func__, __LINE__, lf->pathname); 179 error = EFTYPE; 180 goto out; 181 } 182 183 if (cth.cth_version != CTF_VERSION_2 && 184 cth.cth_version != CTF_VERSION_3) { 185 printf( 186 "%s(%d): module %s CTF format has unsupported version %d\n", 187 __func__, __LINE__, lf->pathname, cth.cth_version); 188 error = EFTYPE; 189 goto out; 190 } 191 192 /* Check if the data is compressed. */ 193 if ((cth.cth_flags & CTF_F_COMPRESS) != 0) { 194 /* 195 * The last two fields in the CTF header are the offset 196 * from the end of the header to the start of the string 197 * data and the length of that string data. Use this 198 * information to determine the decompressed CTF data 199 * buffer required. 200 */ 201 sz = cth.cth_stroff + cth.cth_strlen + sizeof(cth); 202 203 /* 204 * Allocate memory for the compressed CTF data, including 205 * the header (which isn't compressed). 206 */ 207 raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK); 208 } else { 209 /* 210 * The CTF data is not compressed, so the ELF section 211 * size is the same as the buffer size required. 212 */ 213 sz = shdr[i].sh_size; 214 } 215 216 /* 217 * Allocate memory to buffer the CTF data in its decompressed 218 * form. 219 */ 220 ctftab = malloc(sz, M_LINKER, M_WAITOK); 221 222 /* 223 * Read the CTF data into the raw buffer if compressed, or 224 * directly into the CTF buffer otherwise. 225 */ 226 if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw, 227 shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 228 td->td_ucred, NOCRED, NULL, td)) != 0) 229 goto out; 230 231 /* Check if decompression is required. */ 232 if (raw != NULL) { 233 uLongf destlen; 234 int ret; 235 236 /* 237 * The header isn't compressed, so copy that into the 238 * CTF buffer first. 239 */ 240 bcopy(&cth, ctftab, sizeof(cth)); 241 242 destlen = sz - sizeof(cth); 243 ret = uncompress(ctftab + sizeof(cth), &destlen, 244 raw + sizeof(cth), shdr[i].sh_size - sizeof(cth)); 245 if (ret != Z_OK) { 246 printf("%s(%d): zlib uncompress returned %d\n", 247 __func__, __LINE__, ret); 248 error = EIO; 249 goto out; 250 } 251 } 252 253 /* Got the CTF data! */ 254 ef->ctftab = ctftab; 255 ef->ctfcnt = shdr[i].sh_size; 256 257 /* We'll retain the memory allocated for the CTF data. */ 258 ctftab = NULL; 259 260 /* Let the caller use the CTF data read. */ 261 lc->ctftab = ef->ctftab; 262 lc->ctfcnt = ef->ctfcnt; 263 lc->symtab = ef->ddbsymtab; 264 lc->strtab = ef->ddbstrtab; 265 lc->strcnt = ef->ddbstrcnt; 266 lc->nsym = ef->ddbsymcnt; 267 lc->ctfoffp = (uint32_t **) &ef->ctfoff; 268 lc->typoffp = (uint32_t **) &ef->typoff; 269 lc->typlenp = &ef->typlen; 270 271 out: 272 VOP_UNLOCK(nd.ni_vp); 273 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 274 275 if (hdr != NULL) 276 free(hdr, M_LINKER); 277 if (shdr != NULL) 278 free(shdr, M_LINKER); 279 if (shstrtab != NULL) 280 free(shstrtab, M_LINKER); 281 if (ctftab != NULL) 282 free(ctftab, M_LINKER); 283 if (raw != NULL) 284 free(raw, M_LINKER); 285 #else 286 error = EOPNOTSUPP; 287 #endif 288 289 return (error); 290 } 291