kern_ctf.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    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  * $FreeBSD$
   29  */
   30 
   31 #include <sys/ctf.h>
   32 
   33 /*
   34  * Note this file is included by both link_elf.c and link_elf_obj.c.
   35  */
   36 
   37 #ifdef DDB_CTF
   38 #include <contrib/zlib/zlib.h>
   39 #endif
   40 
   41 static int
   42 link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
   43 {
   44 #ifdef DDB_CTF
   45         Elf_Ehdr *hdr = NULL;
   46         Elf_Shdr *shdr = NULL;
   47         caddr_t ctftab = NULL;
   48         caddr_t raw = NULL;
   49         caddr_t shstrtab = NULL;
   50         elf_file_t ef = (elf_file_t) lf;
   51         int flags;
   52         int i;
   53         int nbytes;
   54         size_t sz;
   55         struct nameidata nd;
   56         struct thread *td = curthread;
   57         struct ctf_header cth;
   58 #endif
   59         int error = 0;
   60 
   61         if (lf == NULL || lc == NULL)
   62                 return (EINVAL);
   63 
   64         /* Set the defaults for no CTF present. That's not a crime! */
   65         bzero(lc, sizeof(*lc));
   66 
   67 #ifdef DDB_CTF
   68         /*
   69          * First check if we've tried to load CTF data previously and the
   70          * CTF ELF section wasn't found. We flag that condition by setting
   71          * ctfcnt to -1. See below.
   72          */
   73         if (ef->ctfcnt < 0)
   74                 return (EFTYPE);
   75 
   76         /* Now check if we've already loaded the CTF data.. */
   77         if (ef->ctfcnt > 0) {
   78                 /* We only need to load once. */
   79                 lc->ctftab = ef->ctftab;
   80                 lc->ctfcnt = ef->ctfcnt;
   81                 lc->symtab = ef->ddbsymtab;
   82                 lc->strtab = ef->ddbstrtab;
   83                 lc->strcnt = ef->ddbstrcnt;
   84                 lc->nsym   = ef->ddbsymcnt;
   85                 lc->ctfoffp = (uint32_t **) &ef->ctfoff;
   86                 lc->typoffp = (uint32_t **) &ef->typoff;
   87                 lc->typlenp = &ef->typlen;
   88                 return (0);
   89         }
   90 
   91         /*
   92          * We need to try reading the CTF data. Flag no CTF data present
   93          * by default and if we actually succeed in reading it, we'll
   94          * update ctfcnt to the number of bytes read.
   95          */
   96         ef->ctfcnt = -1;
   97 
   98         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, lf->pathname, td);
   99         flags = FREAD;
  100         error = vn_open(&nd, &flags, 0, NULL);
  101         if (error)
  102                 return (error);
  103         NDFREE(&nd, NDF_ONLY_PNBUF);
  104 
  105         /* Allocate memory for the FLF header. */
  106         hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
  107 
  108         /* Read the ELF header. */
  109         if ((error = vn_rdwr(UIO_READ, nd.ni_vp, hdr, sizeof(*hdr),
  110             0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL,
  111             td)) != 0)
  112                 goto out;
  113 
  114         /* Sanity check. */
  115         if (!IS_ELF(*hdr)) {
  116                 error = ENOEXEC;
  117                 goto out;
  118         }
  119 
  120         nbytes = hdr->e_shnum * hdr->e_shentsize;
  121         if (nbytes == 0 || hdr->e_shoff == 0 ||
  122             hdr->e_shentsize != sizeof(Elf_Shdr)) {
  123                 error = ENOEXEC;
  124                 goto out;
  125         }
  126 
  127         /* Allocate memory for all the section headers */
  128         shdr = malloc(nbytes, M_LINKER, M_WAITOK);
  129 
  130         /* Read all the section headers */
  131         if ((error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes,
  132             hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
  133             NULL, td)) != 0)
  134                 goto out;
  135 
  136         /*
  137          * We need to search for the CTF section by name, so if the
  138          * section names aren't present, then we can't locate the
  139          * .SUNW_ctf section containing the CTF data.
  140          */
  141         if (hdr->e_shstrndx == 0 || shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
  142                 printf("%s(%d): module %s e_shstrndx is %d, sh_type is %d\n",
  143                     __func__, __LINE__, lf->pathname, hdr->e_shstrndx,
  144                     shdr[hdr->e_shstrndx].sh_type);
  145                 error = EFTYPE;
  146                 goto out;
  147         }
  148 
  149         /* Allocate memory to buffer the section header strings. */
  150         shstrtab = malloc(shdr[hdr->e_shstrndx].sh_size, M_LINKER, M_WAITOK);
  151 
  152         /* Read the section header strings. */
  153         if ((error = vn_rdwr(UIO_READ, nd.ni_vp, shstrtab,
  154             shdr[hdr->e_shstrndx].sh_size, shdr[hdr->e_shstrndx].sh_offset,
  155             UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, NULL, td)) != 0)
  156                 goto out;
  157 
  158         /* Search for the section containing the CTF data. */
  159         for (i = 0; i < hdr->e_shnum; i++)
  160                 if (strcmp(".SUNW_ctf", shstrtab + shdr[i].sh_name) == 0)
  161                         break;
  162 
  163         /* Check if the CTF section wasn't found. */
  164         if (i >= hdr->e_shnum) {
  165                 printf("%s(%d): module %s has no .SUNW_ctf section\n",
  166                     __func__, __LINE__, lf->pathname);
  167                 error = EFTYPE;
  168                 goto out;
  169         }
  170 
  171         /* Read the CTF header. */
  172         if ((error = vn_rdwr(UIO_READ, nd.ni_vp, &cth, sizeof(cth),
  173             shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
  174             NOCRED, NULL, td)) != 0)
  175                 goto out;
  176 
  177         /* Check the CTF magic number. */
  178         if (cth.cth_magic != CTF_MAGIC) {
  179                 printf("%s(%d): module %s has invalid format\n",
  180                     __func__, __LINE__, lf->pathname);
  181                 error = EFTYPE;
  182                 goto out;
  183         }
  184 
  185         if (cth.cth_version != CTF_VERSION_2 &&
  186             cth.cth_version != CTF_VERSION_3) {
  187                 printf(
  188                     "%s(%d): module %s CTF format has unsupported version %d\n",
  189                     __func__, __LINE__, lf->pathname, cth.cth_version);
  190                 error = EFTYPE;
  191                 goto out;
  192         }
  193 
  194         /* Check if the data is compressed. */
  195         if ((cth.cth_flags & CTF_F_COMPRESS) != 0) {
  196                 /*
  197                  * The last two fields in the CTF header are the offset
  198                  * from the end of the header to the start of the string
  199                  * data and the length of that string data. Use this
  200                  * information to determine the decompressed CTF data
  201                  * buffer required.
  202                  */
  203                 sz = cth.cth_stroff + cth.cth_strlen + sizeof(cth);
  204 
  205                 /*
  206                  * Allocate memory for the compressed CTF data, including
  207                  * the header (which isn't compressed).
  208                  */
  209                 raw = malloc(shdr[i].sh_size, M_LINKER, M_WAITOK);
  210         } else {
  211                 /*
  212                  * The CTF data is not compressed, so the ELF section
  213                  * size is the same as the buffer size required.
  214                  */
  215                 sz = shdr[i].sh_size;
  216         }
  217 
  218         /*
  219          * Allocate memory to buffer the CTF data in its decompressed
  220          * form.
  221          */
  222         ctftab = malloc(sz, M_LINKER, M_WAITOK);
  223 
  224         /*
  225          * Read the CTF data into the raw buffer if compressed, or
  226          * directly into the CTF buffer otherwise.
  227          */
  228         if ((error = vn_rdwr(UIO_READ, nd.ni_vp, raw == NULL ? ctftab : raw,
  229             shdr[i].sh_size, shdr[i].sh_offset, UIO_SYSSPACE, IO_NODELOCKED,
  230             td->td_ucred, NOCRED, NULL, td)) != 0)
  231                 goto out;
  232 
  233         /* Check if decompression is required. */
  234         if (raw != NULL) {
  235                 uLongf destlen;
  236                 int ret;
  237 
  238                 /*
  239                  * The header isn't compressed, so copy that into the
  240                  * CTF buffer first.
  241                  */
  242                 bcopy(&cth, ctftab, sizeof(cth));
  243 
  244                 destlen = sz - sizeof(cth);
  245                 ret = uncompress(ctftab + sizeof(cth), &destlen,
  246                     raw + sizeof(cth), shdr[i].sh_size - sizeof(cth));
  247                 if (ret != Z_OK) {
  248                         printf("%s(%d): zlib uncompress returned %d\n",
  249                             __func__, __LINE__, ret);
  250                         error = EIO;
  251                         goto out;
  252                 }
  253         }
  254 
  255         /* Got the CTF data! */
  256         ef->ctftab = ctftab;
  257         ef->ctfcnt = shdr[i].sh_size;
  258 
  259         /* We'll retain the memory allocated for the CTF data. */
  260         ctftab = NULL;
  261 
  262         /* Let the caller use the CTF data read. */
  263         lc->ctftab = ef->ctftab;
  264         lc->ctfcnt = ef->ctfcnt;
  265         lc->symtab = ef->ddbsymtab;
  266         lc->strtab = ef->ddbstrtab;
  267         lc->strcnt = ef->ddbstrcnt;
  268         lc->nsym   = ef->ddbsymcnt;
  269         lc->ctfoffp = (uint32_t **) &ef->ctfoff;
  270         lc->typoffp = (uint32_t **) &ef->typoff;
  271         lc->typlenp = &ef->typlen;
  272 
  273 out:
  274         VOP_UNLOCK(nd.ni_vp);
  275         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
  276 
  277         if (hdr != NULL)
  278                 free(hdr, M_LINKER);
  279         if (shdr != NULL)
  280                 free(shdr, M_LINKER);
  281         if (shstrtab != NULL)
  282                 free(shstrtab, M_LINKER);
  283         if (ctftab != NULL)
  284                 free(ctftab, M_LINKER);
  285         if (raw != NULL)
  286                 free(raw, M_LINKER);
  287 #else
  288         error = EOPNOTSUPP;
  289 #endif
  290 
  291         return (error);
  292 }
Cache object: 88e26951adbfc092e9dafaaec043b80a
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_ctf.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ctf.c
