The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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

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    1 /*      $NetBSD: kern_ctf.c,v 1.8 2021/04/06 07:57:03 simonb Exp $      */
    2 /*-
    3  * Copyright (c) 2008 John Birrell <jb@freebsd.org>
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   25  * SUCH DAMAGE.
   26  *
   27  * $FreeBSD: src/sys/kern/kern_ctf.c,v 1.1.4.1 2009/08/03 08:13:06 kensmith Exp $
   28  */
   29 
   30 #define ELFSIZE ARCH_ELFSIZE
   31 #include <sys/proc.h>
   32 #include <sys/module.h>
   33 #include <sys/exec.h>
   34 #include <sys/exec_elf.h>
   35 #include <sys/kmem.h>
   36 #include <sys/malloc.h>
   37 #include <sys/kobj_impl.h>
   38 #include <sys/kobj.h>
   39 #include <sys/kern_ctf.h>
   40 
   41 #define _KSYMS_PRIVATE
   42 #include <sys/ksyms.h>
   43 
   44 #include <net/zlib.h>
   45 
   46 /*
   47  * Note this file is included by both link_elf.c and link_elf_obj.c.
   48  *
   49  * The CTF header structure definition can't be used here because it's
   50  * (annoyingly) covered by the CDDL. We will just use a few bytes from
   51  * it as an integer array where we 'know' what they mean.
   52  */
   53 #define CTF_HDR_SIZE            36
   54 #define CTF_HDR_STRTAB_U32      7
   55 #define CTF_HDR_STRLEN_U32      8
   56 
   57 static void *
   58 z_alloc(void *nil, u_int items, u_int size)
   59 {
   60         void *ptr;
   61 
   62         ptr = malloc(items * size, M_TEMP, M_NOWAIT);
   63         return ptr;
   64 }
   65 
   66 static void
   67 z_free(void *nil, void *ptr)
   68 {
   69         free(ptr, M_TEMP);
   70 }
   71 
   72 int
   73 mod_ctf_get(struct module *mod, mod_ctf_t **mcp)
   74 {
   75         mod_ctf_t *mc;
   76         struct ksyms_symtab *st;
   77         void * ctftab = NULL;
   78         size_t sz;
   79         int error = 0;
   80         int compressed = 0;
   81 
   82         void *ctfbuf = NULL;
   83         uint8_t *ctfaddr;
   84         uint16_t ctfmagic;
   85         size_t ctfsize;
   86 
   87         /*
   88          * Return the cached mc if there is one already.
   89          */
   90 
   91         extern specificdata_key_t fbt_module_key;
   92 
   93         mc = module_getspecific(mod, fbt_module_key);
   94         if (mc != NULL) {
   95                 *mcp = mc;
   96                 return (0);
   97         }
   98 
   99         /*
  100          * Allocate and initialize a new mc.
  101          */
  102 
  103         mc = kmem_zalloc(sizeof(mod_ctf_t), KM_SLEEP);
  104         st = ksyms_get_mod(module_name(mod));
  105         if (st != NULL) {
  106                 mc->nmap     = st->sd_nmap;
  107                 mc->nmapsize = st->sd_nmapsize;
  108         }
  109 
  110         if (mod->mod_kobj == NULL) {
  111                 /* no kobj entry, try building from ksyms list */
  112                 if (st == NULL) {
  113                         error = ENOENT;
  114                         goto out;
  115                 }
  116 
  117                 ctfaddr = st->sd_ctfstart;
  118                 ctfsize = st->sd_ctfsize;
  119 
  120                 mc->symtab = st->sd_symstart;
  121                 mc->strtab = st->sd_strstart;
  122                 mc->strcnt = 0;         /* XXX TBD */
  123                 mc->nsym   = st->sd_symsize / sizeof(Elf_Sym);
  124         } else {
  125                 if (kobj_find_section(mod->mod_kobj, ".SUNW_ctf", (void **)&ctfaddr, &ctfsize)) {
  126                         error = ENOENT;
  127                         goto out;
  128                 }
  129 
  130                 mc->symtab = mod->mod_kobj->ko_symtab;
  131                 mc->strtab = mod->mod_kobj->ko_strtab;
  132                 mc->strcnt = 0;         /* XXX TBD */
  133                 mc->nsym   = mod->mod_kobj->ko_symcnt;
  134         }
  135 
  136         if (ctfaddr == NULL) {
  137                 error = ENOENT;
  138                 goto out;
  139         }
  140 
  141         /* Check the CTF magic number. */
  142         memcpy(&ctfmagic, ctfaddr, sizeof ctfmagic);
  143         if (ctfmagic != CTF_MAGIC) {
  144                 error = EINVAL;
  145                 goto out;
  146         }
  147 
  148         /* Check if version 2. */
  149         if (ctfaddr[2] != 2) {
  150                 error = EINVAL;
  151                 goto out;
  152         }
  153 
  154         /* Check if the data is compressed. */
  155         if ((ctfaddr[3] & 0x1) != 0) {
  156                 uint32_t *u32 = (uint32_t *) ctfaddr;
  157 
  158                 /*
  159                  * The last two fields in the CTF header are the offset
  160                  * from the end of the header to the start of the string
  161                  * data and the length of that string data. se this
  162                  * information to determine the decompressed CTF data
  163                  * buffer required.
  164                  */
  165                 sz = u32[CTF_HDR_STRTAB_U32] + u32[CTF_HDR_STRLEN_U32] +
  166                     CTF_HDR_SIZE;
  167 
  168                 compressed = 1;
  169         } else {
  170                 /*
  171                  * The CTF data is not compressed, so the ELF section
  172                  * size is the same as the buffer size required.
  173                  */
  174                 sz = ctfsize;
  175         }
  176 
  177         /*
  178          * Allocate memory to buffer the CTF data in its decompressed
  179          * form.
  180          */
  181         if (compressed) {
  182                 if ((ctfbuf = malloc(sz, M_TEMP, M_WAITOK)) == NULL) {
  183                         error = ENOMEM;
  184                         goto out;
  185                 }
  186                 ctftab = ctfbuf;
  187                 mc->ctfalloc = 1;
  188         } else {
  189                 ctftab = (void *)ctfaddr;
  190         }
  191 
  192         /* Check if decompression is required. */
  193         if (compressed) {
  194                 z_stream zs;
  195                 int ret;
  196 
  197                 /*
  198                  * The header isn't compressed, so copy that into the
  199                  * CTF buffer first.
  200                  */
  201                 memcpy(ctftab, ctfaddr, CTF_HDR_SIZE);
  202 
  203                 /* Initialise the zlib structure. */
  204                 memset(&zs, 0, sizeof(zs));
  205                 zs.zalloc = z_alloc;
  206                 zs.zfree = z_free;
  207 
  208                 if (inflateInit2(&zs, MAX_WBITS) != Z_OK) {
  209                         error = EIO;
  210                         goto out;
  211                 }
  212 
  213                 zs.avail_in = ctfsize - CTF_HDR_SIZE;
  214                 zs.next_in = ctfaddr + CTF_HDR_SIZE;
  215                 zs.avail_out = sz - CTF_HDR_SIZE;
  216                 zs.next_out = ((uint8_t *) ctftab) + CTF_HDR_SIZE;
  217                 inflateReset(&zs);
  218                 if ((ret = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
  219                         printf("%s(%d): zlib inflate returned %d\n", __func__, __LINE__, ret);
  220                         error = EIO;
  221                         goto out;
  222                 }
  223         }
  224 
  225         /* Got the CTF data! */
  226         mc->ctfcnt = ctfsize;
  227         mc->ctftab = ctftab;
  228         ctfbuf = NULL;
  229 
  230         module_setspecific(mod, fbt_module_key, mc);
  231         *mcp = mc;
  232         mc = NULL;
  233 
  234 out:
  235         if (ctfbuf != NULL)
  236                 free(ctfbuf, M_TEMP);
  237         if (mc != NULL)
  238                 kmem_free(mc, sizeof(*mc));
  239 
  240         return (error);
  241 }

Cache object: 9e226a144556a7c5c26e58531948dbf3


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