LCOV - code coverage report
Current view: top level - src - arlib.c (source / functions) Hit Total Coverage
Test: elfutils-0.179 Lines: 99 110 90.0 %
Date: 2020-03-30 14:24:38 Functions: 5 5 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /* Functions to handle creation of Linux archives.
       2             :    Copyright (C) 2007-2012, 2016 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             :    Written by Ulrich Drepper <drepper@redhat.com>, 2007.
       5             : 
       6             :    This file is free software; you can redistribute it and/or modify
       7             :    it under the terms of the GNU General Public License as published by
       8             :    the Free Software Foundation; either version 3 of the License, or
       9             :    (at your option) any later version.
      10             : 
      11             :    elfutils is distributed in the hope that it will be useful, but
      12             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      13             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14             :    GNU General Public License for more details.
      15             : 
      16             :    You should have received a copy of the GNU General Public License
      17             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      18             : 
      19             : #ifdef HAVE_CONFIG_H
      20             : # include <config.h>
      21             : #endif
      22             : 
      23             : #include <assert.h>
      24             : #include <gelf.h>
      25             : #include <inttypes.h>
      26             : #include <libintl.h>
      27             : #include <stdio.h>
      28             : #include <stdlib.h>
      29             : #include <time.h>
      30             : 
      31             : #include <libeu.h>
      32             : 
      33             : #include "system.h"
      34             : #include "arlib.h"
      35             : 
      36             : 
      37             : /* The one symbol table we hanble.  */
      38             : struct arlib_symtab symtab;
      39             : 
      40             : 
      41             : /* Initialize ARLIB_SYMTAB structure.  */
      42             : void
      43           6 : arlib_init (void)
      44             : {
      45             : #define obstack_chunk_alloc xmalloc
      46             : #define obstack_chunk_free free
      47           6 :   obstack_init (&symtab.symsoffob);
      48           6 :   obstack_init (&symtab.symsnameob);
      49           6 :   obstack_init (&symtab.longnamesob);
      50             : 
      51             :   /* We add the archive header here as well, that avoids allocating
      52             :      another memory block.  */
      53           6 :   struct ar_hdr ar_hdr;
      54           6 :   memcpy (ar_hdr.ar_name, "/               ", sizeof (ar_hdr.ar_name));
      55             :   /* Using snprintf here has a problem: the call always wants to add a
      56             :      NUL byte.  We could use a trick whereby we specify the target
      57             :      buffer size longer than it is and this would not actually fail,
      58             :      since all the fields are consecutive and we fill them in
      59             :      sequence (i.e., the NUL byte gets overwritten).  But
      60             :      _FORTIFY_SOURCE=2 would not let us play these games.  Therefore
      61             :      we play it safe.  */
      62           6 :   char tmpbuf[sizeof (ar_hdr.ar_date) + 1];
      63           6 :   int s = snprintf (tmpbuf, sizeof (tmpbuf), "%-*lld",
      64             :                     (int) sizeof (ar_hdr.ar_date),
      65           6 :                     (arlib_deterministic_output ? 0
      66           6 :                      : (long long int) time (NULL)));
      67           6 :   memcpy (ar_hdr.ar_date, tmpbuf, s);
      68           6 :   assert ((sizeof (struct ar_hdr)  % sizeof (uint32_t)) == 0);
      69             : 
      70             :   /* Note the string for the ar_uid and ar_gid cases is longer than
      71             :      necessary.  This does not matter since we copy only as much as
      72             :      necessary but it helps the compiler to use the same string for
      73             :      the ar_mode case.  */
      74           6 :   memcpy (ar_hdr.ar_uid, "0       ", sizeof (ar_hdr.ar_uid));
      75           6 :   memcpy (ar_hdr.ar_gid, "0       ", sizeof (ar_hdr.ar_gid));
      76           6 :   memcpy (ar_hdr.ar_mode, "0       ", sizeof (ar_hdr.ar_mode));
      77           6 :   memcpy (ar_hdr.ar_fmag, ARFMAG, sizeof (ar_hdr.ar_fmag));
      78             : 
      79             :   /* Add the archive header to the file content.  */
      80           6 :   obstack_grow (&symtab.symsoffob, &ar_hdr, sizeof (ar_hdr));
      81             : 
      82             :   /* The first word in the offset table specifies the size.  Create
      83             :      such an entry now.  The real value will be filled-in later.  For
      84             :      all supported platforms the following is true.  */
      85           6 :   assert (sizeof (uint32_t) == sizeof (int));
      86           6 :   obstack_int_grow (&symtab.symsoffob, 0);
      87             : 
      88             :   /* The long name obstack also gets its archive header.  As above,
      89             :      some of the input strings are longer than required but we only
      90             :      copy the necessary part.  */
      91           6 :   memcpy (ar_hdr.ar_name, "//              ", sizeof (ar_hdr.ar_name));
      92           6 :   memcpy (ar_hdr.ar_date, "            ", sizeof (ar_hdr.ar_date));
      93           6 :   memcpy (ar_hdr.ar_uid, "            ", sizeof (ar_hdr.ar_uid));
      94           6 :   memcpy (ar_hdr.ar_gid, "            ", sizeof (ar_hdr.ar_gid));
      95           6 :   memcpy (ar_hdr.ar_mode, "            ", sizeof (ar_hdr.ar_mode));
      96             :   /* The ar_size field will be filled in later and ar_fmag is already OK.  */
      97           6 :   obstack_grow (&symtab.longnamesob, &ar_hdr, sizeof (ar_hdr));
      98             : 
      99             :   /* All other members are zero.  */
     100           6 :   symtab.symsofflen = 0;
     101           6 :   symtab.symsoff = NULL;
     102           6 :   symtab.symsnamelen = 0;
     103           6 :   symtab.symsname = NULL;
     104           6 : }
     105             : 
     106             : 
     107             : /* Finalize ARLIB_SYMTAB content.  */
     108             : void
     109           6 : arlib_finalize (void)
     110             : {
     111             :   /* Note that the size is stored as decimal string in 10 chars,
     112             :      without zero terminator (we add + 1 here only so snprintf can
     113             :      put it at the end, we then don't use it when we memcpy it).  */
     114           6 :   char tmpbuf[sizeof (((struct ar_hdr *) NULL)->ar_size) + 1];
     115             : 
     116           6 :   symtab.longnameslen = obstack_object_size (&symtab.longnamesob);
     117           6 :   if (symtab.longnameslen != sizeof (struct ar_hdr))
     118             :     {
     119           0 :       if ((symtab.longnameslen & 1) != 0)
     120             :         {
     121             :           /* Add one more byte to make length even.  */
     122           0 :           obstack_grow (&symtab.longnamesob, "\n", 1);
     123           0 :           ++symtab.longnameslen;
     124             :         }
     125             : 
     126           0 :       symtab.longnames = obstack_finish (&symtab.longnamesob);
     127             : 
     128           0 :       int s = snprintf (tmpbuf, sizeof (tmpbuf), "%-*" PRIu32 "",
     129             :                         (int) sizeof (((struct ar_hdr *) NULL)->ar_size),
     130           0 :                         (uint32_t) (symtab.longnameslen - sizeof (struct ar_hdr)));
     131           0 :       memcpy (&((struct ar_hdr *) symtab.longnames)->ar_size, tmpbuf, s);
     132             :     }
     133             : 
     134           6 :   symtab.symsofflen = obstack_object_size (&symtab.symsoffob);
     135           6 :   assert (symtab.symsofflen % sizeof (uint32_t) == 0);
     136           6 :   if (symtab.symsofflen != 0)
     137             :     {
     138           6 :       symtab.symsoff = (uint32_t *) obstack_finish (&symtab.symsoffob);
     139             : 
     140             :       /* Fill in the number of offsets now.  */
     141          12 :       symtab.symsoff[AR_HDR_WORDS] = le_bswap_32 ((symtab.symsofflen
     142             :                                                     - sizeof (struct ar_hdr))
     143             :                                                    / sizeof (uint32_t) - 1);
     144             :     }
     145             : 
     146           6 :   symtab.symsnamelen = obstack_object_size (&symtab.symsnameob);
     147           6 :   if ((symtab.symsnamelen & 1) != 0)
     148             :     {
     149             :       /* Add one more NUL byte to make length even.  */
     150           3 :       obstack_grow (&symtab.symsnameob, "", 1);
     151           3 :       ++symtab.symsnamelen;
     152             :     }
     153           6 :   symtab.symsname = obstack_finish (&symtab.symsnameob);
     154             : 
     155             :   /* Determine correction for the offsets in the symbol table.   */
     156           6 :   off_t disp = 0;
     157           6 :   if (symtab.symsnamelen > 0)
     158           3 :     disp = symtab.symsofflen + symtab.symsnamelen;
     159           6 :   if (symtab.longnameslen > sizeof (struct ar_hdr))
     160           0 :     disp += symtab.longnameslen;
     161             : 
     162           6 :   if (disp != 0 && symtab.symsoff != NULL)
     163             :     {
     164           3 :       uint32_t nsyms = le_bswap_32 (symtab.symsoff[AR_HDR_WORDS]);
     165             : 
     166          69 :       for (uint32_t cnt = 1; cnt <= nsyms; ++cnt)
     167             :         {
     168          66 :           uint32_t val = le_bswap_32 (symtab.symsoff[AR_HDR_WORDS + cnt]);
     169          66 :           val += disp;
     170         132 :           symtab.symsoff[AR_HDR_WORDS + cnt] = le_bswap_32 (val);
     171             :         }
     172             :     }
     173             : 
     174             :   /* See comment for ar_date above.  */
     175          18 :   memcpy (&((struct ar_hdr *) symtab.symsoff)->ar_size, tmpbuf,
     176          12 :           snprintf (tmpbuf, sizeof (tmpbuf), "%-*" PRIu32 "",
     177             :                     (int) sizeof (((struct ar_hdr *) NULL)->ar_size),
     178           6 :                     (uint32_t) (symtab.symsofflen + symtab.symsnamelen
     179             :                                 - sizeof (struct ar_hdr))));
     180           6 : }
     181             : 
     182             : 
     183             : /* Free resources for ARLIB_SYMTAB.  */
     184             : void
     185           6 : arlib_fini (void)
     186             : {
     187           6 :   obstack_free (&symtab.symsoffob, NULL);
     188           6 :   obstack_free (&symtab.symsnameob, NULL);
     189           6 :   obstack_free (&symtab.longnamesob, NULL);
     190           6 : }
     191             : 
     192             : 
     193             : /* Add name a file offset of a symbol.  */
     194             : void
     195          66 : arlib_add_symref (const char *symname, off_t symoff)
     196             : {
     197             :   /* For all supported platforms the following is true.  */
     198          66 :   assert (sizeof (uint32_t) == sizeof (int));
     199          66 :   obstack_int_grow (&symtab.symsoffob, (int) le_bswap_32 (symoff));
     200             : 
     201          66 :   size_t symname_len = strlen (symname) + 1;
     202          66 :   obstack_grow (&symtab.symsnameob, symname, symname_len);
     203          66 : }
     204             : 
     205             : 
     206             : /* Add symbols from ELF with value OFFSET to the symbol table SYMTAB.  */
     207             : void
     208          30 : arlib_add_symbols (Elf *elf, const char *arfname, const char *membername,
     209             :                    off_t off)
     210             : {
     211          30 :   if (sizeof (off) > sizeof (uint32_t) && off > ~((uint32_t) 0))
     212             :     /* The archive is too big.  */
     213           0 :     error (EXIT_FAILURE, 0, gettext ("the archive '%s' is too large"),
     214             :            arfname);
     215             : 
     216             :   /* We only add symbol tables for ELF files.  It makes not much sense
     217             :      to add symbols from executables but we do so for compatibility.
     218             :      For DSOs and executables we use the dynamic symbol table, for
     219             :      relocatable files all the DT_SYMTAB tables.  */
     220          30 :   if (elf_kind (elf) != ELF_K_ELF)
     221           4 :     return;
     222             : 
     223          26 :   GElf_Ehdr ehdr_mem;
     224          26 :   GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
     225          26 :   if (ehdr == NULL)
     226           0 :     error (EXIT_FAILURE, 0, gettext ("cannot read ELF header of %s(%s): %s"),
     227             :            arfname, membername, elf_errmsg (-1));
     228             : 
     229          26 :   GElf_Word symtype;
     230          26 :   if (ehdr->e_type == ET_REL)
     231             :     symtype = SHT_SYMTAB;
     232           0 :   else if (ehdr->e_type == ET_EXEC || ehdr->e_type == ET_DYN)
     233             :     symtype = SHT_DYNSYM;
     234             :   else
     235             :     /* We do not handle that type.  */
     236             :     return;
     237             : 
     238             :   /* Iterate over all sections.  */
     239          26 :   Elf_Scn *scn = NULL;
     240         881 :   while ((scn = elf_nextscn (elf, scn)) != NULL)
     241             :     {
     242             :       /* Get the section header.  */
     243         855 :       GElf_Shdr shdr_mem;
     244         855 :       GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
     245         855 :       if (shdr == NULL)
     246         829 :         continue;
     247             : 
     248         855 :       if (shdr->sh_type != symtype)
     249             :         continue;
     250             : 
     251          26 :       Elf_Data *data = elf_getdata (scn, NULL);
     252          26 :       if (data == NULL)
     253             :         continue;
     254             : 
     255          26 :       if (shdr->sh_entsize == 0)
     256             :         continue;
     257             : 
     258          26 :       int nsyms = shdr->sh_size / shdr->sh_entsize;
     259        1355 :       for (int ndx = shdr->sh_info; ndx < nsyms; ++ndx)
     260             :         {
     261        1329 :           GElf_Sym sym_mem;
     262        1329 :           GElf_Sym *sym = gelf_getsym (data, ndx, &sym_mem);
     263        1329 :           if (sym == NULL)
     264        1263 :             continue;
     265             : 
     266             :           /* Ignore undefined symbols.  */
     267        1329 :           if (sym->st_shndx == SHN_UNDEF)
     268             :             continue;
     269             : 
     270             :           /* Use this symbol.  */
     271          66 :           const char *symname = elf_strptr (elf, shdr->sh_link, sym->st_name);
     272          66 :           if (symname != NULL)
     273          66 :             arlib_add_symref (symname, off);
     274             :         }
     275             : 
     276             :       /* Only relocatable files can have more than one symbol table.  */
     277          26 :       if (ehdr->e_type != ET_REL)
     278             :         break;
     279             :     }
     280             : }

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