LCOV - code coverage report
Current view: top level - libtasn1-2.x/gl - read-file.c (source / functions) Hit Total Coverage
Test: GNU Libtasn1 Lines: 31 59 52.5 %
Date: 2012-09-24 Functions: 3 4 75.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 11 32 34.4 %

           Branch data     Line data    Source code
       1                 :            : /* read-file.c -- read file contents into a string
       2                 :            :    Copyright (C) 2006, 2009-2012 Free Software Foundation, Inc.
       3                 :            :    Written by Simon Josefsson and Bruno Haible.
       4                 :            : 
       5                 :            :    This program is free software; you can redistribute it and/or modify
       6                 :            :    it under the terms of the GNU General Public License as published by
       7                 :            :    the Free Software Foundation; either version 3, or (at your option)
       8                 :            :    any later version.
       9                 :            : 
      10                 :            :    This program is distributed in the hope that it will be useful,
      11                 :            :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      12                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13                 :            :    GNU General Public License for more details.
      14                 :            : 
      15                 :            :    You should have received a copy of the GNU General Public License
      16                 :            :    along with this program; if not, see <http://www.gnu.org/licenses/>.  */
      17                 :            : 
      18                 :            : #include <config.h>
      19                 :            : 
      20                 :            : #include "read-file.h"
      21                 :            : 
      22                 :            : /* Get fstat.  */
      23                 :            : #include <sys/stat.h>
      24                 :            : 
      25                 :            : /* Get ftello.  */
      26                 :            : #include <stdio.h>
      27                 :            : 
      28                 :            : /* Get SIZE_MAX.  */
      29                 :            : #include <stdint.h>
      30                 :            : 
      31                 :            : /* Get malloc, realloc, free. */
      32                 :            : #include <stdlib.h>
      33                 :            : 
      34                 :            : /* Get errno. */
      35                 :            : #include <errno.h>
      36                 :            : 
      37                 :            : /* Read a STREAM and return a newly allocated string with the content,
      38                 :            :    and set *LENGTH to the length of the string.  The string is
      39                 :            :    zero-terminated, but the terminating zero byte is not counted in
      40                 :            :    *LENGTH.  On errors, *LENGTH is undefined, errno preserves the
      41                 :            :    values set by system functions (if any), and NULL is returned.  */
      42                 :            : char *
      43                 :          1 : fread_file (FILE *stream, size_t *length)
      44                 :            : {
      45                 :          1 :   char *buf = NULL;
      46                 :          1 :   size_t alloc = BUFSIZ;
      47                 :            : 
      48                 :            :   /* For a regular file, allocate a buffer that has exactly the right
      49                 :            :      size.  This avoids the need to do dynamic reallocations later.  */
      50                 :            :   {
      51                 :            :     struct stat st;
      52                 :            : 
      53 [ +  - ][ +  - ]:          1 :     if (fstat (fileno (stream), &st) >= 0 && S_ISREG (st.st_mode))
      54                 :            :       {
      55                 :          1 :         off_t pos = ftello (stream);
      56                 :            : 
      57 [ +  - ][ +  - ]:          1 :         if (pos >= 0 && pos < st.st_size)
      58                 :            :           {
      59                 :          1 :             off_t alloc_off = st.st_size - pos;
      60                 :            : 
      61                 :            :             /* '1' below, accounts for the trailing NUL.  */
      62         [ -  + ]:          1 :             if (SIZE_MAX - 1 < alloc_off)
      63                 :            :               {
      64                 :          0 :                 errno = ENOMEM;
      65                 :          0 :                 return NULL;
      66                 :            :               }
      67                 :            : 
      68                 :          1 :             alloc = alloc_off + 1;
      69                 :            :           }
      70                 :            :       }
      71                 :            :   }
      72                 :            : 
      73         [ -  + ]:          1 :   if (!(buf = malloc (alloc)))
      74                 :          0 :     return NULL; /* errno is ENOMEM.  */
      75                 :            : 
      76                 :            :   {
      77                 :          1 :     size_t size = 0; /* number of bytes read so far */
      78                 :            :     int save_errno;
      79                 :            : 
      80                 :            :     for (;;)
      81                 :            :       {
      82                 :            :         /* This reads 1 more than the size of a regular file
      83                 :            :            so that we get eof immediately.  */
      84                 :          1 :         size_t requested = alloc - size;
      85                 :          1 :         size_t count = fread (buf + size, 1, requested, stream);
      86                 :          1 :         size += count;
      87                 :            : 
      88         [ +  - ]:          1 :         if (count != requested)
      89                 :            :           {
      90                 :          1 :             save_errno = errno;
      91         [ -  + ]:          1 :             if (ferror (stream))
      92                 :          0 :               break;
      93                 :            : 
      94                 :            :             /* Shrink the allocated memory if possible.  */
      95         [ -  + ]:          1 :             if (size < alloc - 1)
      96                 :            :               {
      97                 :          0 :                 char *smaller_buf = realloc (buf, size + 1);
      98         [ #  # ]:          0 :                 if (smaller_buf != NULL)
      99                 :          0 :                   buf = smaller_buf;
     100                 :            :               }
     101                 :            : 
     102                 :          1 :             buf[size] = '\0';
     103                 :          1 :             *length = size;
     104                 :          1 :             return buf;
     105                 :            :           }
     106                 :            : 
     107                 :            :         {
     108                 :            :           char *new_buf;
     109                 :            : 
     110         [ #  # ]:          0 :           if (alloc == SIZE_MAX)
     111                 :            :             {
     112                 :          0 :               save_errno = ENOMEM;
     113                 :          0 :               break;
     114                 :            :             }
     115                 :            : 
     116         [ #  # ]:          0 :           if (alloc < SIZE_MAX - alloc / 2)
     117                 :          0 :             alloc = alloc + alloc / 2;
     118                 :            :           else
     119                 :          0 :             alloc = SIZE_MAX;
     120                 :            : 
     121         [ #  # ]:          0 :           if (!(new_buf = realloc (buf, alloc)))
     122                 :            :             {
     123                 :          0 :               save_errno = errno;
     124                 :          0 :               break;
     125                 :            :             }
     126                 :            : 
     127                 :          0 :           buf = new_buf;
     128                 :            :         }
     129                 :          0 :       }
     130                 :            : 
     131                 :          0 :     free (buf);
     132                 :          0 :     errno = save_errno;
     133                 :          1 :     return NULL;
     134                 :            :   }
     135                 :            : }
     136                 :            : 
     137                 :            : static char *
     138                 :          1 : internal_read_file (const char *filename, size_t *length, const char *mode)
     139                 :            : {
     140                 :          1 :   FILE *stream = fopen (filename, mode);
     141                 :            :   char *out;
     142                 :            :   int save_errno;
     143                 :            : 
     144         [ -  + ]:          1 :   if (!stream)
     145                 :          0 :     return NULL;
     146                 :            : 
     147                 :          1 :   out = fread_file (stream, length);
     148                 :            : 
     149                 :          1 :   save_errno = errno;
     150                 :            : 
     151         [ -  + ]:          1 :   if (fclose (stream) != 0)
     152                 :            :     {
     153         [ #  # ]:          0 :       if (out)
     154                 :            :         {
     155                 :          0 :           save_errno = errno;
     156                 :          0 :           free (out);
     157                 :            :         }
     158                 :          0 :       errno = save_errno;
     159                 :          0 :       return NULL;
     160                 :            :     }
     161                 :            : 
     162                 :          1 :   return out;
     163                 :            : }
     164                 :            : 
     165                 :            : /* Open and read the contents of FILENAME, and return a newly
     166                 :            :    allocated string with the content, and set *LENGTH to the length of
     167                 :            :    the string.  The string is zero-terminated, but the terminating
     168                 :            :    zero byte is not counted in *LENGTH.  On errors, *LENGTH is
     169                 :            :    undefined, errno preserves the values set by system functions (if
     170                 :            :    any), and NULL is returned.  */
     171                 :            : char *
     172                 :          0 : read_file (const char *filename, size_t *length)
     173                 :            : {
     174                 :          0 :   return internal_read_file (filename, length, "r");
     175                 :            : }
     176                 :            : 
     177                 :            : /* Open (on non-POSIX systems, in binary mode) and read the contents
     178                 :            :    of FILENAME, and return a newly allocated string with the content,
     179                 :            :    and set LENGTH to the length of the string.  The string is
     180                 :            :    zero-terminated, but the terminating zero byte is not counted in
     181                 :            :    the LENGTH variable.  On errors, *LENGTH is undefined, errno
     182                 :            :    preserves the values set by system functions (if any), and NULL is
     183                 :            :    returned.  */
     184                 :            : char *
     185                 :          1 : read_binary_file (const char *filename, size_t *length)
     186                 :            : {
     187                 :          1 :   return internal_read_file (filename, length, "rb");
     188                 :            : }

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