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      1 /* Create descriptor from file descriptor for processing file.
      2    Copyright (C) 2002, 2003, 2004 Red Hat, Inc.
      3    Written by Ulrich Drepper <drepper (at) redhat.com>, 2002.
      4 
      5    This program is Open Source software; you can redistribute it and/or
      6    modify it under the terms of the Open Software License version 1.0 as
      7    published by the Open Source Initiative.
      8 
      9    You should have received a copy of the Open Software License along
     10    with this program; if not, you may obtain a copy of the Open Software
     11    License version 1.0 from http://www.opensource.org/licenses/osl.php or
     12    by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
     13    3001 King Ranch Road, Ukiah, CA 95482.   */
     14 
     15 #ifdef HAVE_CONFIG_H
     16 # include <config.h>
     17 #endif
     18 
     19 #include <errno.h>
     20 #include <stddef.h>
     21 #include <sys/stat.h>
     22 
     23 #include <libdwP.h>
     24 
     25 
     26 Dwarf *
     27 dwarf_begin (fd, cmd)
     28      int fd;
     29      Dwarf_Cmd cmd;
     30 {
     31   Elf *elf;
     32   Elf_Cmd elfcmd;
     33   Dwarf *result = NULL;
     34 
     35   switch (cmd)
     36     {
     37     case DWARF_C_READ:
     38       elfcmd = ELF_C_READ_MMAP;
     39       break;
     40     case DWARF_C_WRITE:
     41       elfcmd = ELF_C_WRITE;
     42       break;
     43     case DWARF_C_RDWR:
     44       elfcmd = ELF_C_RDWR;
     45       break;
     46     default:
     47       /* No valid mode.  */
     48       __libdw_seterrno (DWARF_E_INVALID_CMD);
     49       return NULL;
     50     }
     51 
     52   /* We have to call `elf_version' here since the user might have not
     53      done it or initialized libelf with a different version.  This
     54      would break libdwarf since we are using the ELF data structures
     55      in a certain way.  */
     56   elf_version (EV_CURRENT);
     57 
     58   /* Get an ELF descriptor.  */
     59   elf = elf_begin (fd, elfcmd, NULL);
     60   if (elf == NULL)
     61     {
     62       /* Test why the `elf_begin" call failed.  */
     63       struct stat64 st;
     64 
     65       if (fstat64 (fd, &st) == 0 && ! S_ISREG (st.st_mode))
     66 	__libdw_seterrno (DWARF_E_NO_REGFILE);
     67       else if (errno == EBADF)
     68 	__libdw_seterrno (DWARF_E_INVALID_FILE);
     69       else
     70 	__libdw_seterrno (DWARF_E_IO_ERROR);
     71     }
     72   else
     73     {
     74       /* Do the real work now that we have an ELF descriptor.  */
     75       result = dwarf_begin_elf (elf, cmd, NULL);
     76 
     77       /* If this failed, free the resources.  */
     78       if (result == NULL)
     79 	elf_end (elf);
     80       else
     81 	result->free_elf = true;
     82     }
     83 
     84   return result;
     85 }
     86