src/libcaptive/rtl/file.c

   1 /* $Id$
   2  * File handling utilities of libcaptive
   3  * Copyright (C) 2002 Jan Kratochvil <project-captive@jankratochvil.net>
   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; exactly version 2 of June 1991 is required
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19
  20 #include "config.h"
  21
  22 #include "captive/file.h"       /* self */
  23 #include <glib/gtypes.h>
  24 #include <glib/gmessages.h>
  25 #include <glib/ghash.h>
  26 #include <sys/types.h>
  27 #include <unistd.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <fcntl.h>
  31 #include <sys/mman.h>
  32
  33
  34 /* map: address -> GSIZE_TO_POINTER(length) */
  35 static GHashTable *captive_file_mmap_hash;
  36
  37 /* initialize 'captive_file_mmap_hash' */
  38 static void captive_file_mmap_hash_init(void)
  39 {
  40         if (captive_file_mmap_hash)
  41                 return;
  42         captive_file_mmap_hash=g_hash_table_new(g_direct_hash,g_direct_equal);
  43 }
  44
  45 /**
  46  * captive_file_mmap:
  47  * @lenp: returns the file length if successful. %NULL pointer permitted.
  48  * @path: File pathname to open(2).
  49  * @open_flags: open(2) parameter #flags such as %O_RDONLY.
  50  * @mmap_prot: mmap(2) parameter #prot such as %PROT_READ.
  51  * @mmap_flags: mmap(2) parameter #flags such as %MAP_SHARED.
  52  *
  53  * mmap(2) the whole file into memory.
  54  *
  55  * Returns: address base with mmap(2)ed file (and @lenp filled) or #NULL if error.
  56  */
  57 gpointer captive_file_mmap(size_t *lenp,const gchar *path,int open_flags,int mmap_prot,int mmap_flags)
  58 {
  59 gpointer r;
  60 int fd;
  61 size_t len;
  62 off_t lenoff;
  63
  64         captive_file_mmap_hash_init();
  65
  66         /* FIXME: use g_filename_from_utf8() on 'path' */
  67         fd=open(path,open_flags);
  68         if (fd==-1) {
  69                 g_error("captive_file_mmap(\"%s\"): open: %m",path);
  70                 goto err;
  71                 }
  72
  73         lenoff=lseek(fd,0,SEEK_END);
  74         if (lenoff==(off_t)-1) {
  75                 g_assert_not_reached();
  76                 goto err_close;
  77                 }
  78         len=(size_t)lenoff;
  79         if (lenp)
  80                 *lenp=len;
  81
  82         r=mmap(
  83                         0,      /* start */
  84                         len,    /* len */
  85                         mmap_prot,
  86                         mmap_flags,
  87                         fd,
  88                         0       /* offset */
  89                         );
  90         if (r==NULL) {
  91                 g_assert_not_reached();
  92                 goto err_close;
  93                 }
  94
  95         if (close(fd)) {
  96                 g_assert_not_reached();
  97                 goto err_munmap;
  98                 }
  99
 100         /* should make no difference with g_hash_table_replace()
 101          * as we are using (g_direct_hash,g_direct_equal)
 102          */
 103         g_hash_table_insert(captive_file_mmap_hash,
 104                         r,GSIZE_TO_POINTER(len));       /* key,value */
 105
 106         return r;
 107
 108 err_munmap:
 109         /* errors ignored */
 110         munmap(r,len);
 111 err_close:
 112         /* errors ignored */
 113         close(fd);
 114 err:
 115         g_return_val_if_reached(NULL);
 116 }
 117
 118 /**
 119  * captive_file_munmap:
 120  * @base: file base address returned by captive_file_mmap(). %NULL pointer forbidden.
 121  *
 122  * munmap(2) the whole file and destroy all its resources.
 123  */
 124 void captive_file_munmap(gpointer base)
 125 {
 126 gpointer len_ptr;       /* GSIZE_TO_POINTER(off_t len) */
 127 gboolean found;
 128
 129         g_return_if_fail(base!=NULL);
 130
 131         captive_file_mmap_hash_init();
 132
 133         /* report if 'base' not found */
 134         found=g_hash_table_lookup_extended(captive_file_mmap_hash,
 135                         base,   /* lookup_key */
 136                         NULL,   /* orig_key */
 137                         &len_ptr);      /* value */
 138         g_return_if_fail(found==TRUE);
 139
 140         /* remove 'base' from our database */
 141         found=g_hash_table_remove(captive_file_mmap_hash,
 142                         base);  /* key */
 143         g_return_if_fail(found==TRUE);  /* just a warning would be also possible */
 144
 145         /* munmap() has no return value */
 146         munmap(base,GPOINTER_TO_SIZE(len_ptr));
 147 }