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      1 /* Return program header table entry.
      2    Copyright (C) 1998-2010, 2015 Red Hat, Inc.
      3    This file is part of elfutils.
      4    Written by Ulrich Drepper <drepper (at) redhat.com>, 1998.
      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 <gelf.h>
     35 #include <string.h>
     36 #include <stdbool.h>
     37 
     38 #include "libelfP.h"
     39 
     40 
     41 GElf_Phdr *
     42 gelf_getphdr (Elf *elf, int ndx, GElf_Phdr *dst)
     43 {
     44   GElf_Phdr *result = NULL;
     45 
     46   if (elf == NULL)
     47     return NULL;
     48 
     49   if (unlikely (elf->kind != ELF_K_ELF))
     50     {
     51       __libelf_seterrno (ELF_E_INVALID_HANDLE);
     52       return NULL;
     53     }
     54 
     55   if (dst == NULL)
     56     {
     57       __libelf_seterrno (ELF_E_INVALID_OPERAND);
     58       return NULL;
     59     }
     60 
     61   rwlock_rdlock (elf->lock);
     62 
     63   if (elf->class == ELFCLASS32)
     64     {
     65       /* Copy the elements one-by-one.  */
     66       Elf32_Phdr *phdr = elf->state.elf32.phdr;
     67 
     68       if (phdr == NULL)
     69 	{
     70 	  rwlock_unlock (elf->lock);
     71 	  phdr = INTUSE(elf32_getphdr) (elf);
     72 	  if (phdr == NULL)
     73 	    /* The error number is already set.  */
     74 	    return NULL;
     75 	  rwlock_rdlock (elf->lock);
     76 	}
     77 
     78       /* Test whether the index is ok.  */
     79       size_t phnum;
     80       if (__elf_getphdrnum_chk_rdlock (elf, &phnum) != 0
     81 	  || (size_t) ndx >= phnum)
     82 	{
     83 	  __libelf_seterrno (ELF_E_INVALID_INDEX);
     84 	  goto out;
     85 	}
     86 
     87       /* We know the result now.  */
     88       result = dst;
     89 
     90       /* Now correct the pointer to point to the correct element.  */
     91       phdr += ndx;
     92 
     93 #define COPY(Name) result->Name = phdr->Name
     94       COPY (p_type);
     95       COPY (p_offset);
     96       COPY (p_vaddr);
     97       COPY (p_paddr);
     98       COPY (p_filesz);
     99       COPY (p_memsz);
    100       COPY (p_flags);
    101       COPY (p_align);
    102     }
    103   else
    104     {
    105       /* Copy the elements one-by-one.  */
    106       Elf64_Phdr *phdr = elf->state.elf64.phdr;
    107 
    108       if (phdr == NULL)
    109 	{
    110 	  rwlock_unlock (elf->lock);
    111 	  phdr = INTUSE(elf64_getphdr) (elf);
    112 	  if (phdr == NULL)
    113 	    /* The error number is already set.  */
    114 	    return NULL;
    115 	  rwlock_rdlock (elf->lock);
    116 	}
    117 
    118       /* Test whether the index is ok.  */
    119       size_t phnum;
    120       if (__elf_getphdrnum_chk_rdlock (elf, &phnum) != 0
    121 	  || (size_t) ndx >= phnum)
    122 	{
    123 	  __libelf_seterrno (ELF_E_INVALID_INDEX);
    124 	  goto out;
    125 	}
    126 
    127       /* We only have to copy the data.  */
    128       result = memcpy (dst, phdr + ndx, sizeof (GElf_Phdr));
    129     }
    130 
    131  out:
    132   rwlock_unlock (elf->lock);
    133 
    134   return result;
    135 }
    136