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 #include "main.h"
  36
  37
  38 static G_CONST_RETURN guint8 *bundle_util_file_retrieve(guint32 *data_length_return,const gchar *basename)
  39 {
  40 const guint8 *data;
  41
  42         g_return_val_if_fail(data_length_return!=NULL,NULL);
  43         g_return_val_if_fail(basename!=NULL,NULL);
  44
  45         if (optarg_verbose)
  46                 g_message(_("Retrieving internally stored: %s"),basename);
  47         data=g_hash_table_lookup(bundle_hash_new(),basename);
  48         g_return_val_if_fail(data!=NULL,NULL);
  49         *data_length_return=GUINT32_FROM_BE(*(guint32 *)data);
  50         data+=sizeof(*data_length_return);
  51
  52         return data;
  53 }
  54
  55 /* Returns TRUE if it safe to overwrite/unlink the file.
  56  */
  57 static gboolean bundle_util_file_backup_conditional(const gchar *pathname,const gchar *basename)
  58 {
  59 const guint8 *data;
  60 guint32 data_length;
  61 int fd;
  62 guint8 *data_found;
  63 int got;
  64 char strftime_buffer[LINE_MAX];
  65 const gchar *destination;
  66 time_t time_current;
  67
  68         g_return_val_if_fail(pathname!=NULL,FALSE);
  69         g_return_val_if_fail(basename!=NULL,FALSE);
  70
  71         if (!(data=bundle_util_file_retrieve(&data_length,basename)))
  72                 return FALSE;
  73
  74         if (-1==(fd=open(pathname,O_RDONLY))) {
  75                 if (errno==ENOENT)
  76                         return TRUE;
  77                 else {
  78                         g_warning(_("Error checking file modifications of \"%s\": %m"),pathname);
  79                         return FALSE;
  80                         }
  81                 }
  82
  83         /* WARNING: 'data_found' allocated in this block! */
  84         data_found=g_malloc(data_length+1);
  85         if (-1==(got=read(fd,data_found,data_length+1)))
  86                 g_warning(_("Error reading during the check of file modifications of \"%s\": %m"),pathname);
  87         if (close(fd))
  88                 g_warning(_("Error closing the file \"%s\" during the check of its modifications: %m"),pathname);
  89         /* memcmp(3) requires 'data_found'! */
  90         if (got==(int)data_length && !memcmp(data_found,data,data_length)) {
  91                 g_free(data_found);
  92                 return TRUE;
  93                 }
  94         g_free(data_found);
  95
  96         time_current=time(NULL);        /* It is segfault to gmtime(NULL). */
  97         if (!strftime(strftime_buffer,sizeof(strftime_buffer),"GMT%FT%T",gmtime(&time_current))) {
  98                 g_warning("strftime(3): %m");   /* shouldn't happen */
  99                 return FALSE;
 100                 }
 101         destination=udpgate_printf_alloca("%s-%s-%d",pathname,strftime_buffer,(int)getpid());
 102         if (rename(pathname,destination)) {
 103                 g_warning(_("Error renaming your modified file \"%s\" to the backup \"%s\", giving up: %m"),
 104                                 pathname,destination);
 105                 return FALSE;
 106                 }
 107
 108         return TRUE;
 109 }
 110
 111 gboolean bundle_util_file_remove(const gchar *pathname,const gchar *basename)
 112 {
 113         g_return_val_if_fail(pathname!=NULL,FALSE);
 114         g_return_val_if_fail(basename!=NULL,FALSE);
 115
 116         if (!bundle_util_file_backup_conditional(pathname,basename))
 117                 return FALSE;
 118
 119         if (unlink(pathname) && errno!=ENOENT) {
 120                 g_warning(_("Error removing the file \"%s\": %m"),pathname);
 121                 return FALSE;
 122                 }
 123
 124         return TRUE;
 125 }
 126
 127 gboolean bundle_util_file_write(const gchar *pathname,const gchar *basename,mode_t pathname_mode,gboolean pathname_backup)
 128 {
 129 const guint8 *data;
 130 guint32 data_length;
 131 int fd;
 132
 133         g_return_val_if_fail(pathname!=NULL,FALSE);
 134         g_return_val_if_fail(basename!=NULL,FALSE);
 135
 136         if (!(data=bundle_util_file_retrieve(&data_length,basename)))
 137                 return FALSE;
 138
 139         if (pathname_backup && !bundle_util_file_backup_conditional(pathname,basename))
 140                 return FALSE;
 141
 142         if (-1==(fd=open(pathname,O_WRONLY|O_CREAT|O_TRUNC,pathname_mode))) {
 143                 g_warning(_("Error opening the file \"%s\" for rewrite: %m"),pathname);
 144                 return FALSE;
 145                 }
 146         if ((int)data_length!=write(fd,data,data_length)) {
 147                 g_warning(_("Error writing the data of the file \"%s\" being overwritten: %m"),pathname);
 148                 close(fd);      /* errors ignored */
 149                 return FALSE;
 150                 }
 151         if (close(fd)) {
 152                 g_warning(_("Error closing the file \"%s\" after its rewrite: %m"),pathname);
 153                 return FALSE;
 154                 }
 155         return TRUE;
 156 }