src/bundle-util.c

   1 /* $Id$
   2  * UDP Gateway single-file bundle utility functions
   3  * Copyright (C) 2004 Jan Kratochvil <project-udpgate@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 <glib/gmessages.h>
  23 #include <errno.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <glib/gmem.h>
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <time.h>
  31 #include <stdio.h>
  32
  33 #include "bundle-util.h"        /* self */
  34 #include "bundle.h"
  35
  36
  37 static const guint8 *bundle_util_file_retrieve(guint32 *data_length_return,const gchar *pathname,const gchar *basename)
  38 {
  39 const guint8 *data;
  40
  41         g_return_val_if_fail(data_length_return!=NULL,NULL);
  42         g_return_val_if_fail(pathname!=NULL,NULL);
  43         g_return_val_if_fail(basename!=NULL,NULL);
  44
  45         data=g_hash_table_lookup(bundle_hash_new(),basename);
  46         g_return_val_if_fail(data!=NULL,NULL);
  47         *data_length_return=GUINT32_FROM_BE(*(guint32 *)data);
  48         data+=sizeof(*data_length_return);
  49
  50         return data;
  51 }
  52
  53 /* Returns TRUE if it safe to overwrite/unlink the file.
  54  */
  55 static gboolean bundle_util_file_backup_conditional(const gchar *pathname,const gchar *basename)
  56 {
  57 const guint8 *data;
  58 guint32 data_length;
  59 int fd;
  60 guint8 *data_found;
  61 int got;
  62 char strftime_buffer[LINE_MAX];
  63 const gchar *destination;
  64 time_t time_current;
  65
  66         g_return_val_if_fail(pathname!=NULL,FALSE);
  67         g_return_val_if_fail(basename!=NULL,FALSE);
  68
  69         if (!(data=bundle_util_file_retrieve(&data_length,pathname,basename)))
  70                 return FALSE;
  71
  72         if (-1==(fd=open(pathname,O_RDONLY))) {
  73                 if (errno==ENOENT)
  74                         return TRUE;
  75                 else {
  76                         g_warning(_("Error checking file modifications of \"%s\": %m"),pathname);
  77                         return FALSE;
  78                         }
  79                 }
  80
  81         /* WARNING: 'data_found' allocated in this block! */
  82         data_found=g_malloc(data_length+1);
  83         if (-1==(got=read(fd,data_found,data_length+1)))
  84                 g_warning(_("Error reading during the check of file modifications of \"%s\": %m"),pathname);
  85         if (close(fd))
  86                 g_warning(_("Error closing the file \"%s\" during the check of its modifications: %m"),pathname);
  87         g_free(data_found);
  88
  89         if (got==(int)data_length && !memcmp(data_found,data,data_length))
  90                 return TRUE;
  91
  92         time_current=time(NULL);        /* It is segfault to gmtime(NULL). */
  93         if (!strftime(strftime_buffer,sizeof(strftime_buffer),"GMT%FT%T",gmtime(&time_current))) {
  94                 g_warning("strftime(3): %m");   /* shouldn't happen */
  95                 return FALSE;
  96                 }
  97         destination=udpgate_printf_alloca("%s-%s-%d",pathname,strftime_buffer,(int)getpid());
  98         if (rename(pathname,destination)) {
  99                 g_warning(_("Error renaming your modified file \"%s\" to the backup \"%s\", giving up: %m"),
 100                                 pathname,destination);
 101                 return FALSE;
 102                 }
 103
 104         return TRUE;
 105 }
 106
 107 gboolean bundle_util_file_remove(const gchar *pathname,const gchar *basename)
 108 {
 109         g_return_val_if_fail(pathname!=NULL,FALSE);
 110         g_return_val_if_fail(basename!=NULL,FALSE);
 111
 112         if (!bundle_util_file_backup_conditional(pathname,basename))
 113                 return FALSE;
 114
 115         if (unlink(pathname) && errno!=ENOENT) {
 116                 g_warning(_("Error removing the file \"%s\": %m"),pathname);
 117                 return FALSE;
 118                 }
 119
 120         return TRUE;
 121 }
 122
 123 gboolean bundle_util_file_write(const gchar *pathname,const gchar *basename,mode_t pathname_mode)
 124 {
 125 const guint8 *data;
 126 guint32 data_length;
 127 int fd;
 128
 129         g_return_val_if_fail(pathname!=NULL,FALSE);
 130         g_return_val_if_fail(basename!=NULL,FALSE);
 131
 132         if (!(data=bundle_util_file_retrieve(&data_length,pathname,basename)))
 133                 return FALSE;
 134
 135         if (!bundle_util_file_backup_conditional(pathname,basename))
 136                 return FALSE;
 137
 138         if (-1==(fd=open(pathname,O_WRONLY|O_CREAT|O_TRUNC,pathname_mode))) {
 139                 g_warning(_("Error opening the file \"%s\" for rewrite: %m"),pathname);
 140                 return FALSE;
 141                 }
 142         if ((int)data_length!=write(fd,data,data_length)) {
 143                 g_warning(_("Error writing the data of the file \"%s\" being overwritten: %m"),pathname);
 144                 close(fd);      /* errors ignored */
 145                 return FALSE;
 146                 }
 147         if (close(fd)) {
 148                 g_warning(_("Error closing the file \"%s\" after its rewrite: %m"),pathname);
 149                 return FALSE;
 150                 }
 151         return TRUE;
 152 }