LCOV - code coverage report
Current view: top level - libasm - asm_newscn.c (source / functions) Hit Total Coverage
Test: elfutils-0.191 Lines: 37 68 54.4 %
Date: 2024-07-04 23:21:52 Functions: 2 3 66.7 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 9 38 23.7 %

           Branch data     Line data    Source code
       1                 :            : /* Create new section in output file.
       2                 :            :    Copyright (C) 2002-2011, 2016 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Written by Ulrich Drepper <drepper@redhat.com>, 2002.
       5                 :            : 
       6                 :            :    This file is free software; you can redistribute it and/or modify
       7                 :            :    it under the terms of either
       8                 :            : 
       9                 :            :      * the GNU Lesser General Public License as published by the Free
      10                 :            :        Software Foundation; either version 3 of the License, or (at
      11                 :            :        your option) any later version
      12                 :            : 
      13                 :            :    or
      14                 :            : 
      15                 :            :      * the GNU General Public License as published by the Free
      16                 :            :        Software Foundation; either version 2 of the License, or (at
      17                 :            :        your option) any later version
      18                 :            : 
      19                 :            :    or both in parallel, as here.
      20                 :            : 
      21                 :            :    elfutils is distributed in the hope that it will be useful, but
      22                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      23                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      24                 :            :    General Public License for more details.
      25                 :            : 
      26                 :            :    You should have received copies of the GNU General Public License and
      27                 :            :    the GNU Lesser General Public License along with this program.  If
      28                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      29                 :            : 
      30                 :            : #ifdef HAVE_CONFIG_H
      31                 :            : # include <config.h>
      32                 :            : #endif
      33                 :            : 
      34                 :            : #include <assert.h>
      35                 :            : #include <stdlib.h>
      36                 :            : #include <string.h>
      37                 :            : 
      38                 :            : #include <libasmP.h>
      39                 :            : #include <libelf.h>
      40                 :            : #include <system.h>
      41                 :            : 
      42                 :            : 
      43                 :            : /* Memory for the default pattern.  The type uses a flexible array
      44                 :            :    which does work well with a static initializer.  Work around this by
      45                 :            :    wrapping it in a union, whose second member is a char array 1 byte larger
      46                 :            :    than struct FillPattern.  According to 6.7.9, this does what we need:
      47                 :            : 
      48                 :            :         If an object that has static or thread storage duration is not
      49                 :            :         initialized explicitly, then ... if it is a union, the first named
      50                 :            :         member is initialized (recursively) according to these rules, and
      51                 :            :         any padding is initialized to zero bits.  */
      52                 :            : 
      53                 :            : static const union
      54                 :            : {
      55                 :            :   struct FillPattern pattern;
      56                 :            :   char zeroes[sizeof(struct FillPattern) + 1];
      57                 :            : } xdefault_pattern =
      58                 :            :   {
      59                 :            :     .pattern =
      60                 :            :     {
      61                 :            :       .len = 1
      62                 :            :     },
      63                 :            :   };
      64                 :            : const struct FillPattern *__libasm_default_pattern = &xdefault_pattern.pattern;
      65                 :            : 
      66                 :            : 
      67                 :            : static AsmScn_t *
      68                 :          0 : text_newscn (AsmScn_t *result, GElf_Word type, GElf_Xword flags)
      69                 :            : {
      70                 :            :   /* Buffer where we construct the flag string.  */
      71                 :          0 :   char flagstr[sizeof (GElf_Xword) * 8 + 5];
      72                 :          0 :   char *wp = flagstr;
      73                 :          0 :   const char *typestr = "";
      74                 :            : 
      75                 :            :   /* Only write out the flag string if this is the first time the
      76                 :            :      section is selected.  Some assemblers cannot cope with the
      77                 :            :      .section pseudo-op otherwise.  */
      78         [ #  # ]:          0 :   wp = stpcpy (wp, ", \"");
      79                 :            : 
      80         [ #  # ]:          0 :   if (flags & SHF_WRITE)
      81                 :          0 :     *wp++ = 'w';
      82         [ #  # ]:          0 :   if (flags & SHF_ALLOC)
      83                 :          0 :     *wp++ = 'a';
      84         [ #  # ]:          0 :   if (flags & SHF_EXECINSTR)
      85                 :          0 :     *wp++ = 'x';
      86         [ #  # ]:          0 :   if (flags & SHF_MERGE)
      87                 :          0 :     *wp++ = 'M';
      88         [ #  # ]:          0 :   if (flags & SHF_STRINGS)
      89                 :          0 :     *wp++ = 'S';
      90         [ #  # ]:          0 :   if (flags & SHF_LINK_ORDER)
      91                 :          0 :     *wp++ = 'L';
      92                 :            : 
      93                 :          0 :   *wp++ = '"';
      94                 :            : 
      95         [ #  # ]:          0 :   if (type == SHT_PROGBITS)
      96                 :            :     typestr = ",@progbits";
      97         [ #  # ]:          0 :   else if (type == SHT_NOBITS)
      98                 :          0 :     typestr = ",@nobits";
      99                 :            : 
     100                 :            :   /* Terminate the string.  */
     101                 :          0 :   *wp = '\0';
     102                 :            : 
     103                 :          0 :   fprintf (result->ctx->out.file, "\t.section \"%s\"%s%s\n",
     104                 :          0 :            result->name, flagstr, typestr);
     105                 :            : 
     106                 :          0 :   return result;
     107                 :            : }
     108                 :            : 
     109                 :            : 
     110                 :            : static AsmScn_t *
     111                 :     352010 : binary_newscn (AsmScn_t *result, GElf_Word type, GElf_Xword flags,
     112                 :            :                size_t scnname_len)
     113                 :            : {
     114                 :     352010 :   GElf_Shdr shdr_mem;
     115                 :     352010 :   GElf_Shdr *shdr;
     116                 :     352010 :   Elf_Scn *scn;
     117                 :            : 
     118                 :            :   /* The initial subsection has the number zero.  */
     119                 :     352010 :   result->subsection_id = 0;
     120                 :            : 
     121                 :            :   /* We start at offset zero.  */
     122                 :     352010 :   result->offset = 0;
     123                 :            :   /* And generic alignment.  */
     124                 :     352010 :   result->max_align = 1;
     125                 :            : 
     126                 :            :   /* No output yet.  */
     127                 :     352010 :   result->content = NULL;
     128                 :            : 
     129                 :            :   /* Put the default fill pattern in place.  */
     130                 :     352010 :   result->pattern = (struct FillPattern *) __libasm_default_pattern;
     131                 :            : 
     132                 :            :   /* There are no subsections so far.  */
     133                 :     352010 :   result->subnext = NULL;
     134                 :            : 
     135                 :            :   /* Add the name to the section header string table.  */
     136                 :     704020 :   result->data.main.strent = dwelf_strtab_add_len (result->ctx->section_strtab,
     137                 :     352010 :                                                    result->name, scnname_len);
     138         [ -  + ]:     352010 :   assert (result->data.main.strent != NULL);
     139                 :            : 
     140                 :            :   /* Create the new ELF section.  */
     141                 :     352010 :   result->data.main.scn = scn = elf_newscn (result->ctx->out.elf);
     142         [ -  + ]:     352010 :   if (scn == NULL)
     143                 :            :     {
     144                 :          0 :       free (result);
     145                 :          0 :       __libasm_seterrno (ASM_E_LIBELF);
     146                 :          0 :       return NULL;
     147                 :            :     }
     148                 :            : 
     149                 :            :   /* Not part of a section group (yet).  */
     150                 :     352010 :   result->data.main.next_in_group = NULL;
     151                 :            : 
     152                 :            :   /* Remember the flags.  */
     153                 :     352010 :   shdr = gelf_getshdr (scn, &shdr_mem);
     154                 :            : 
     155                 :     352010 :   shdr->sh_flags = flags;
     156                 :     352010 :   result->type = shdr->sh_type = type;
     157                 :            : 
     158                 :     352010 :   (void) gelf_update_shdr (scn, shdr);
     159                 :            : 
     160                 :     352010 :   return result;
     161                 :            : }
     162                 :            : 
     163                 :            : 
     164                 :            : AsmScn_t *
     165                 :     352010 : asm_newscn (AsmCtx_t *ctx, const char *scnname, GElf_Word type,
     166                 :            :             GElf_Xword flags)
     167                 :            : {
     168                 :     352010 :   size_t scnname_len = strlen (scnname) + 1;
     169                 :     352010 :   AsmScn_t *result;
     170                 :            : 
     171                 :            :   /* If no context is given there might be an earlier error.  */
     172         [ -  + ]:     352010 :   if (ctx == NULL)
     173                 :            :     return NULL;
     174                 :            : 
     175                 :            :   /* Check whether only flags are set which areselectable by the user.  */
     176         [ +  - ]:     352010 :   if (unlikely ((flags & ~(SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR | SHF_MERGE
     177                 :            :                            | SHF_STRINGS | SHF_LINK_ORDER)) != 0)
     178                 :            :       /* We allow only two section types: data and data without file
     179                 :            :          representation.  */
     180   [ -  +  -  - ]:     352010 :       || (type != SHT_PROGBITS && unlikely (type != SHT_NOBITS)))
     181                 :            :     {
     182                 :          0 :       __libasm_seterrno (ASM_E_INVALID);
     183                 :          0 :       return NULL;
     184                 :            :     }
     185                 :            : 
     186                 :     352010 :   rwlock_wrlock (ctx->lock);
     187                 :            : 
     188                 :            :   /* This is a new section.  */
     189                 :     352010 :   result = malloc (sizeof (AsmScn_t) + scnname_len);
     190         [ -  + ]:     352010 :   if (result != NULL)
     191                 :            :     {
     192                 :            :       /* Add the name.  */
     193         [ -  + ]:     352010 :       memcpy (result->name, scnname, scnname_len);
     194                 :            : 
     195                 :            :       /* Add the reference to the context.  */
     196                 :     352010 :       result->ctx = ctx;
     197                 :            : 
     198                 :            :       /* Perform operations according to output mode.  */
     199                 :     704020 :       result = (unlikely (ctx->textp)
     200                 :          0 :                 ? text_newscn (result, type, flags)
     201         [ -  + ]:     352010 :                 : binary_newscn (result, type, flags, scnname_len));
     202                 :            : 
     203                 :            :       /* If everything went well finally add the new section to the hash
     204                 :            :          table.  */
     205         [ -  + ]:     352010 :       if (result != NULL)
     206                 :            :         {
     207                 :     352010 :           result->allnext = ctx->section_list;
     208                 :     352010 :           ctx->section_list = result;
     209                 :            :         }
     210                 :            :     }
     211                 :            : 
     212                 :            :   rwlock_unlock (ctx->lock);
     213                 :            : 
     214                 :            :   return result;
     215                 :            : }
     216                 :            : INTDEF(asm_newscn)

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