-
A few years ago, I was involved in a project planning to use
-Windows file servers as home directory servers for Debian
-Edu/Skolelinux machines. This was thought to be no problem, as the
-access would be through the SMB network file system protocol, and we
-knew other sites used SMB with unix and samba as the file server to
-mount home directories without any problems. But, after months of
-struggling, we had to conclude that our goal was impossible.
-
-
The reason is simply that while SMB can be used for home
-directories when the file server is Samba running on Unix, this only
-work because of Samba have some extensions and the fact that the
-underlying file system is a unix file system. When using a Windows
-file server, the underlying file system do not have POSIX semantics,
-and several programs will fail if the users home directory where they
-want to store their configuration lack POSIX semantics.
-
-
As part of this work, I wrote a small C program I want to share
-with you all, to replicate a few of the problematic applications (like
-OpenOffice.org and GCompris) and see if the file system was working as
-it should. If you find yourself in spooky file system land, it might
-help you find your way out again. This is the fs-test.c source:
-
-
-/*
- * Some tests to check the file system sematics. Used to verify that
- * CIFS from a windows server do not work properly as a linux home
- * directory.
- * License: GPL v2 or later
- *
- * needs libsqlite3-dev and build-essential installed
- * compile with: gcc -Wall -lsqlite3 -DTEST_SQLITE fs-test.c -o fs-test
-*/
-
-#define _FILE_OFFSET_BITS 64
-#define _LARGEFILE_SOURCE 1
-#define _LARGEFILE64_SOURCE 1
-
-#define _GNU_SOURCE /* for asprintf() */
-
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <sys/file.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#ifdef TEST_SQLITE
-/*
- * Test sqlite open, as done by gcompris require the libsqlite3-dev
- * package and linking with -lsqlite3. A more low level test is
- * below.
- * See also <URL: http://www.sqlite.org./faq.html#q5 >.
- */
-#include <sqlite3.h>
-#define CREATE_TABLE_USERS \
- "CREATE TABLE users (user_id INT UNIQUE, login TEXT, lastname TEXT, firstname TEXT, birthdate TEXT, class_id INT ); "
-int test_sqlite_open(void) {
- char *zErrMsg;
- char *name = "testsqlite.db";
- sqlite3 *db=NULL;
- unlink(name);
- int rc = sqlite3_open(name, &db);
- if( rc ){
- printf("error: sqlite open of %s failed: %s\n", name, sqlite3_errmsg(db));
- sqlite3_close(db);
- return -1;
- }
-
- /* create tables */
- rc = sqlite3_exec(db,CREATE_TABLE_USERS, NULL, 0, &zErrMsg);
- if( rc != SQLITE_OK ){
- printf("error: sqlite table create failed: %s\n", zErrMsg);
- sqlite3_close(db);
- return -1;
- }
- printf("info: sqlite worked\n");
- sqlite3_close(db);
- return 0;
-}
-#endif /* TEST_SQLITE */
-
-/*
- * Demonstrate locking issue found in gcompris using sqlite3. This
- * work with ext3, but not with cifs server on Windows 2003. This is
- * done in the sqlite3 library.
- * See also
- * <URL:http://www.cygwin.com/ml/cygwin/2001-08/msg00854.html> and the
- * POSIX specification
- * <URL:http://www.opengroup.org/onlinepubs/009695399/functions/fcntl.html>.
- */
-int test_gcompris_locking(void) {
- struct flock fl;
- char *name = "testsqlite.db";
- unlink(name);
- int fd = open(name, O_RDWR|O_CREAT|O_LARGEFILE, 0644);
- printf("info: testing fcntl locking\n");
-
- fl.l_whence = SEEK_SET;
- fl.l_pid = getpid();
- printf(" Read-locking 1 byte from 1073741824");
- fl.l_start = 1073741824;
- fl.l_len = 1;
- fl.l_type = F_RDLCK;
- if (0 != fcntl(fd, F_SETLK, &fl) ) printf(" - error!\n"); else printf("\n");
-
- printf(" Read-locking 510 byte from 1073741826");
- fl.l_start = 1073741826;
- fl.l_len = 510;
- fl.l_type = F_RDLCK;
- if (0 != fcntl(fd, F_SETLK, &fl) ) printf(" - error!\n"); else printf("\n");
-
- printf(" Unlocking 1 byte from 1073741824");
- fl.l_start = 1073741824;
- fl.l_len = 1;
- fl.l_type = F_UNLCK;
- if (0 != fcntl(fd, F_SETLK, &fl) ) printf(" - error!\n"); else printf("\n");
-
- printf(" Write-locking 1 byte from 1073741824");
- fl.l_start = 1073741824;
- fl.l_len = 1;
- fl.l_type = F_WRLCK;
- if (0 != fcntl(fd, F_SETLK, &fl) ) printf(" - error!\n"); else printf("\n");
-
- printf(" Write-locking 510 byte from 1073741826");
- fl.l_start = 1073741826;
- fl.l_len = 510;
- if (0 != fcntl(fd, F_SETLK, &fl) ) printf(" - error!\n"); else printf("\n");
-
- printf(" Unlocking 2 byte from 1073741824");
- fl.l_start = 1073741824;
- fl.l_len = 2;
- fl.l_type = F_UNLCK;
- if (0 != fcntl(fd, F_SETLK, &fl) ) printf(" - error!\n"); else printf("\n");
-
- close(fd);
- return 0;
-}
-
-/*
- * Test if permissions of freshly created directories allow entries
- * below them. This was a problem with OpenOffice.org and gcompris.
- * Mounting with option 'sync' seem to solve this problem while
- * slowing down file operations.
- */
-int test_subdirectory_creation(void) {
-#define LEVELS 5
- char *path = strdup("test");
- char *dirs[LEVELS];
- int level;
- printf("info: testing subdirectory creation\n");
- for (level = 0; level < LEVELS; level++) {
- char *newpath = NULL;
- if (-1 == mkdir(path, 0777)) {
- printf(" error: Unable to create directory '%s': %s\n",
- path, strerror(errno));
- break;
- }
- asprintf(&newpath, "%s/%s", path, "test");
- free(path);
- path = newpath;
- }
- return 0;
-}
-
-/*
- * Test if symlinks can be created. This was a problem detected with
- * KDE.
- */
-int test_symlinks(void) {
- printf("info: testing symlink creation\n");
- unlink("symlink");
- if (-1 == symlink("file", "symlink"))
- printf(" error: Unable to create symlink\n");
- return 0;
-}
-
-int main(int argc, char **argv) {
- printf("Testing POSIX/Unix sematics on file system\n");
- test_symlinks();
- test_subdirectory_creation();
-#ifdef TEST_SQLITE
- test_sqlite_open();
-#endif /* TEST_SQLITE */
- test_gcompris_locking();
- return 0;
-}
-
-
-
When everything is working, it should print something like
-this:
-
-
-Testing POSIX/Unix sematics on file system
-info: testing symlink creation
-info: testing subdirectory creation
-info: sqlite worked
-info: testing fcntl locking
- Read-locking 1 byte from 1073741824
- Read-locking 510 byte from 1073741826
- Unlocking 1 byte from 1073741824
- Write-locking 1 byte from 1073741824
- Write-locking 510 byte from 1073741826
- Unlocking 2 byte from 1073741824
-
-
-
I do not remember the exact details of the problems we saw, but one
-of them was with locking, where if I remember correctly, POSIX allow a
-read-only lock to be upgraded to a read-write lock without unlocking
-the read-only lock (while Windows do not). Another was a bug in the
-CIFS/SMB client implementation in the Linux kernel where directory
-meta information would be wrong for a fraction of a second, making
-OpenOffice.org fail to create its deep directory tree because it was
-not allowed to create files in its freshly created directory.
-
-
Anyway, here is a nice tool for your tool box, might you never need
-it. :)
+
In the Debian
+popularity-contest numbers, the adobe-flashplugin package the
+second most popular used package that is missing in Debian. The sixth
+most popular is flashplayer-mozilla. This is a clear indication that
+working flash is important for Debian users. Around 10 percent of the
+users submitting data to popcon.debian.org have this package
+installed.
+
+
In the report written by Lars Risan in August 2008
+(«Skolelinux
+i bruk â Rapport for Hurum kommune, Universitetet i Agder og
+stiftelsen SLX Debian Labs»), one of the most important problems
+schools experienced with Debian
+Edu/Skolelinux was the lack of working Flash. A lot of educational
+web sites require Flash to work, and lacking working Flash support in
+the web browser and the problems with installing it was perceived as a
+good reason to stay with Windows.
+
+
I once saw a funny and sad comment in a web forum, where Linux was
+said to be the retarded cousin that did not really understand
+everything you told him but could work fairly well. This was a
+comment regarding the problems Linux have with proprietary formats and
+non-standard web pages, and is sad because it exposes a fairly common
+understanding of whose fault it is if web pages that only work in for
+example Internet Explorer 6 fail to work on Firefox, and funny because
+it explain very well how annoying it is for users when Linux
+distributions do not work with the documents they receive or the web
+pages they want to visit.
+
+
This is part of the reason why I believe it is important for Debian
+and Debian Edu to have a well working Flash implementation in the
+distribution, to get at least popular sites as Youtube and Google
+Video to working out of the box. For Squeeze, Debian have the chance
+to include the latest version of Gnash that will make this happen, as
+the new release 0.8.8 was published a few weeks ago and is resting in
+unstable. The new version work with more sites that version 0.8.7.
+The Gnash maintainers have asked for a freeze exception, but the
+release team have not had time to reply to it yet. I hope they agree
+with me that Flash is important for the Debian desktop users, and thus
+accept the new package into Squeeze.