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 #include <glib/gstrfuncs.h>
  33
  34 #include "bundle-util.h"        /* self */
  35 #include "bundle.h"
  36 #include "main.h"
  37
  38
  39 static G_CONST_RETURN guint8 *bundle_util_file_retrieve(guint32 *data_length_return,const gchar *basename)
  40 {
  41 const guint8 *data;
  42
  43         g_return_val_if_fail(data_length_return!=NULL,NULL);
  44         g_return_val_if_fail(basename!=NULL,NULL);
  45
  46         if (optarg_verbose)
  47                 g_message(_("Retrieving internally stored: %s"),basename);
  48         data=g_hash_table_lookup(bundle_hash_new(),basename);
  49         g_return_val_if_fail(data!=NULL,NULL);
  50         *data_length_return=GUINT32_FROM_BE(*(guint32 *)data);
  51         data+=sizeof(*data_length_return);
  52
  53         return data;
  54 }
  55
  56 /* Returns TRUE if it safe to overwrite/unlink the file.
  57  */
  58 static gboolean bundle_util_file_backup_conditional(const gchar *pathname,const gchar *basename)
  59 {
  60 const guint8 *data;
  61 guint32 data_length;
  62 int fd;
  63 guint8 *data_found;
  64 int got;
  65 char strftime_buffer[LINE_MAX];
  66 const gchar *destination;
  67 time_t time_current;
  68
  69         g_return_val_if_fail(pathname!=NULL,FALSE);
  70         g_return_val_if_fail(basename!=NULL,FALSE);
  71
  72         if (!(data=bundle_util_file_retrieve(&data_length,basename)))
  73                 return FALSE;
  74
  75         if (-1==(fd=open(pathname,O_RDONLY))) {
  76                 if (errno==ENOENT)
  77                         return TRUE;
  78                 else {
  79                         g_warning(_("Error checking file modifications of \"%s\": %m"),pathname);
  80                         return FALSE;
  81                         }
  82                 }
  83
  84         /* WARNING: 'data_found' allocated in this block! */
  85         data_found=g_malloc(data_length+1);
  86         if (-1==(got=read(fd,data_found,data_length+1)))
  87                 g_warning(_("Error reading during the check of file modifications of \"%s\": %m"),pathname);
  88         if (close(fd))
  89                 g_warning(_("Error closing the file \"%s\" during the check of its modifications: %m"),pathname);
  90         /* memcmp(3) requires 'data_found'! */
  91         if (got==(int)data_length && !memcmp(data_found,data,data_length)) {
  92                 g_free(data_found);
  93                 return TRUE;
  94                 }
  95         g_free(data_found);
  96
  97         time_current=time(NULL);        /* It is segfault to gmtime(NULL). */
  98         if (!strftime(strftime_buffer,sizeof(strftime_buffer),"GMT%FT%T",gmtime(&time_current))) {
  99                 g_warning("strftime(3): %m");   /* shouldn't happen */
 100                 return FALSE;
 101                 }
 102         destination=udpgate_printf_alloca("%s-%s-%d",pathname,strftime_buffer,(int)getpid());
 103         if (rename(pathname,destination)) {
 104                 g_warning(_("Error renaming your modified file \"%s\" to the backup \"%s\", giving up: %m"),
 105                                 pathname,destination);
 106                 return FALSE;
 107                 }
 108
 109         return TRUE;
 110 }
 111
 112 gboolean bundle_util_file_remove(const gchar *pathname,const gchar *basename)
 113 {
 114         g_return_val_if_fail(pathname!=NULL,FALSE);
 115         g_return_val_if_fail(basename!=NULL,FALSE);
 116
 117         if (!bundle_util_file_backup_conditional(pathname,basename))
 118                 return FALSE;
 119
 120         if (unlink(pathname) && errno!=ENOENT) {
 121                 g_warning(_("Error removing the file \"%s\": %m"),pathname);
 122                 return FALSE;
 123                 }
 124
 125         return TRUE;
 126 }
 127
 128 struct dir_stack {
 129         struct dir_stack *next;
 130         gchar *dirname; /* in fact 'pathname' */
 131         };
 132
 133 /* Always creates up to 'dirname(pathname)', never 'pathname' itself! */
 134 static struct dir_stack *pathname_mkdirs(const gchar *pathname,mode_t mode)
 135 {
 136 gchar *dirname;
 137 struct dir_stack *r;
 138
 139         g_return_val_if_fail(pathname!=NULL,NULL);
 140
 141         dirname=g_path_get_dirname(pathname);
 142         if (!strcmp(dirname,pathname)) {
 143                 g_free(dirname);
 144                 dirname=NULL;
 145                 }
 146         if (!dirname)
 147                 return NULL;
 148         r=pathname_mkdirs(dirname,mode);
 149         if (mkdir(dirname,mode))
 150                 g_free(dirname);
 151         else {
 152 struct dir_stack *dir_stack;
 153
 154                 udpgate_new(dir_stack);
 155                 dir_stack->dirname=dirname;
 156                 dir_stack->next=r;
 157                 r=dir_stack;
 158                 }
 159         return r;
 160 }
 161
 162 static struct dir_stack *bundle_util_file_write_atexit_dir_stack_head;
 163 struct file_stack {
 164         struct file_stack *next;
 165         gchar *pathname;
 166         gchar *basename;
 167         };
 168 static struct file_stack *bundle_util_file_write_atexit_file_stack_head;
 169
 170 static void bundle_util_file_write_atexit(void)
 171 {
 172 struct file_stack *file_stack;
 173 struct dir_stack *dir_stack;
 174
 175         /* Always remove files first before their directories! */
 176         while ((file_stack=bundle_util_file_write_atexit_file_stack_head)) {
 177                 /* Errors already reported: */
 178                 bundle_util_file_remove(file_stack->pathname,file_stack->basename);
 179                 g_free(file_stack->pathname);
 180                 g_free(file_stack->basename);
 181                 bundle_util_file_write_atexit_file_stack_head=file_stack->next;
 182                 g_free(file_stack);
 183                 }
 184
 185         while ((dir_stack=bundle_util_file_write_atexit_dir_stack_head)) {
 186                 if (rmdir(dir_stack->dirname))
 187                         g_warning(_("Error cleaning up created temporary directory: %s"),dir_stack->dirname);
 188                 g_free(dir_stack->dirname);
 189                 bundle_util_file_write_atexit_dir_stack_head=dir_stack->next;
 190                 g_free(dir_stack);
 191                 }
 192 }
 193
 194 gboolean bundle_util_file_write(const gchar *pathname,const gchar *basename,mode_t pathname_mode,
 195                 enum bundle_util_flags flags)
 196 {
 197 const guint8 *data;
 198 guint32 data_length;
 199 int fd;
 200 struct dir_stack *mkdirs=NULL;
 201 static gboolean atexited=FALSE;
 202
 203         g_return_val_if_fail(pathname!=NULL,FALSE);
 204         g_return_val_if_fail(basename!=NULL,FALSE);
 205         g_return_val_if_fail(flags&(BUNDLE_UTIL_BACKUP_MASK|BUNDLE_UTIL_MKDIRS_MASK|BUNDLE_UTIL_TEMPORARY_MASK),FALSE);
 206         /* Currently just unsupported: */
 207         g_return_val_if_fail((flags&(BUNDLE_UTIL_MKDIRS_MASK|BUNDLE_UTIL_TEMPORARY_MASK))!=BUNDLE_UTIL_MKDIRS_MASK,FALSE);
 208
 209         if (!(data=bundle_util_file_retrieve(&data_length,basename)))
 210                 return FALSE;
 211
 212         if ((flags&BUNDLE_UTIL_BACKUP_MASK) && !bundle_util_file_backup_conditional(pathname,basename))
 213                 return FALSE;
 214
 215         if (flags&BUNDLE_UTIL_MKDIRS_MASK) {
 216 mode_t dir_mode=pathname_mode;
 217
 218                 dir_mode|=(pathname_mode&0444)>>2;      /* mode|=('r'->'x') */
 219                 mkdirs=pathname_mkdirs(pathname,dir_mode);
 220                 }
 221
 222         if (!atexited) {
 223                 atexited=TRUE;
 224                 g_atexit(bundle_util_file_write_atexit);
 225                 }
 226
 227         if (flags&BUNDLE_UTIL_TEMPORARY_MASK) {
 228 struct dir_stack **mkdirs_tail_pointer;
 229 struct file_stack *file_stack;
 230
 231                 /* Stack current 'mkdirs' in front of the current: bundle_util_file_write_atexit_dir_stack_head
 232                  * to remove them in the reverse order than created.
 233                  * Removal ordering of the current 'mkdirs' stack is preserved
 234                  * as it is already reversed.
 235                  */
 236                 for (mkdirs_tail_pointer=&mkdirs;*mkdirs_tail_pointer;mkdirs_tail_pointer=&(*mkdirs_tail_pointer)->next);
 237                 *mkdirs_tail_pointer=bundle_util_file_write_atexit_dir_stack_head;
 238                 bundle_util_file_write_atexit_dir_stack_head=mkdirs;
 239                 mkdirs=NULL;
 240
 241                 /* Register also the file itself. */
 242                 udpgate_new(file_stack);
 243                 file_stack->pathname=g_strdup(pathname);
 244                 file_stack->basename=g_strdup(basename);
 245                 file_stack->next=bundle_util_file_write_atexit_file_stack_head;
 246                 bundle_util_file_write_atexit_file_stack_head=file_stack;
 247                 }
 248         /* Currently just unsupported: */
 249         g_assert(!mkdirs);
 250
 251         if (-1==(fd=open(pathname,O_WRONLY|O_CREAT|O_TRUNC,pathname_mode))) {
 252                 if (errno!=EPERM)
 253                         g_warning(_("Error opening the file \"%s\" for rewrite: %m"),pathname);
 254                 return FALSE;
 255                 }
 256         if ((int)data_length!=write(fd,data,data_length)) {
 257                 g_warning(_("Error writing the data of the file \"%s\" being overwritten: %m"),pathname);
 258                 close(fd);      /* errors ignored */
 259                 return FALSE;
 260                 }
 261         if (close(fd)) {
 262                 g_warning(_("Error closing the file \"%s\" after its rewrite: %m"),pathname);
 263                 return FALSE;
 264                 }
 265         return TRUE;
 266 }