PlaneteCasio
/
libc
1
0
Fork 0
Code Issues 6 Pull Requests Releases Wiki Activity

Introduce the 'usertemp' filesystem type 

* mount.cc (mount_info::from_fstab_line): Support mounting the current
	user's temp folder as /tmp/.  This is particularly useful a feature
	when Cygwin's own files are write-protected.

	* pathnames.xml: document the new usertemp file system type

Detailed explanation:

In the context of Windows, there is a per-user directory for temporary
files, by default specified via the environment variable %TEMP%. Let's
allow to use that directory for our /tmp/ directory.

With this patch, we introduce the special filesystem type "usertemp":
By specifying

	none /tmp usertemp binary,posix=0 0 0

in /etc/fstab, the /tmp/ directory gets auto-mounted to the directory
specified by the %TEMP% variable.

This feature comes handy in particularly in scenarios where the
administrator might want to write-protect the entire Cygwin directory
yet still needs to allow users to write into the /tmp/ directory.
This is the case in the context of Git for Windows, where the
Cygwin (MSys2) root directory lives inside C:\Program Files and hence
/tmp/ would not be writable otherwise.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This commit is contained in:
Johannes Schindelin 2015-12-01 15:02:14 +01:00 committed by Corinna Vinschen
parent 5644f71428
commit fb71716d2c
5 changed files with 54 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,9 @@
2015-12-07 Johannes Schindelin <johannes.schindelin@gmx.de>
* mount.cc (mount_info::from_fstab_line): Support mounting the current
user's temp folder as /tmp/. This is particularly useful a feature
when Cygwin's own files are write-protected.
2015-12-07 Corinna Vinschen <corinna@vinschen.de>
* include/sys/select.h: Move select(2) macros from newlib's sys/types.h

3
winsup/cygwin/include/sys/mount.h
View File

@ -44,7 +44,8 @@ enum
MOUNT_DOS = 0x40000, /* convert leading spaces and trailing
dots and spaces to private use area */
MOUNT_IHASH = 0x80000, /* Enforce hash values for inode numbers */
MOUNT_BIND = 0x100000 /* Allows bind syntax in fstab file. */
MOUNT_BIND = 0x100000, /* Allows bind syntax in fstab file. */
MOUNT_USER_TEMP = 0x200000 /* Mount the user's $TMP. */
};
int mount (const char *, const char *, unsigned __flags);

21
winsup/cygwin/mount.cc
View File

@ -1186,6 +1186,8 @@ mount_info::from_fstab_line (char *line, bool user)
unsigned mount_flags = MOUNT_SYSTEM | MOUNT_BINARY;
if (!strcmp (fs_type, "cygdrive"))
mount_flags |= MOUNT_NOPOSIX;
if (!strcmp (fs_type, "usertemp"))
mount_flags |= MOUNT_IMMUTABLE;
if (!fstab_read_flags (&c, mount_flags, false))
return true;
if (mount_flags & MOUNT_BIND)
@ -1210,6 +1212,22 @@ mount_info::from_fstab_line (char *line, bool user)
slashify (posix_path, cygdrive, 1);
cygdrive_len = strlen (cygdrive);
}
else if (!strcmp (fs_type, "usertemp"))
{
WCHAR tmp[PATH_MAX + 1];
if (GetTempPathW (PATH_MAX, tmp))
{
tmp_pathbuf tp;
char *mb_tmp = tp.c_get ();
sys_wcstombs (mb_tmp, PATH_MAX, tmp);
mount_flags |= MOUNT_USER_TEMP;
int res = mount_table->add_item (mb_tmp, posix_path, mount_flags);
if (res && get_errno () == EMFILE)
return false;
}
}
else
{
int res = mount_table->add_item (native_path, posix_path, mount_flags);
@ -1667,6 +1685,9 @@ fillout_mntent (const char *native_path, const char *posix_path, unsigned flags)
if (flags & (MOUNT_BIND))
strcat (_my_tls.locals.mnt_opts, (char *) ",bind");
if (flags & (MOUNT_USER_TEMP))
strcat (_my_tls.locals.mnt_opts, (char *) ",usertemp");
ret.mnt_opts = _my_tls.locals.mnt_opts;
ret.mnt_freq = 1;

4
winsup/doc/ChangeLog
View File

@ -1,3 +1,7 @@
2015-12-07 Johannes Schindelin <johannes.schindelin@gmx.de>
* pathnames.xml: Document the new usertemp file system type.
2015-12-06 Corinna Vinschen <corinna@vinschen.de>
* new-features.xml (ov-new2.4): Document cygpath -U option.

24
winsup/doc/pathnames.xml
View File

@ -74,9 +74,10 @@ doesn't matter if you write <literal>FAT</literal> into this field even if
the filesystem is NTFS. Cygwin figures out the filesystem type and its
capabilities by itself.</para>
<para>The only exception is the file system type cygdrive. This type is
used to set the cygdrive prefix. For a description of the cygdrive prefix
see <xref linkend="cygdrive"></xref></para>
<para>The only two exceptions are the file system types cygdrive and usertemp.
The cygdrive type is used to set the cygdrive prefix. For a description of
the cygdrive prefix see <xref linkend="cygdrive"></xref>, for a description of
the usertemp file system type see <xref linkend="usertemp"></xref></para>
<para>The fourth field describes the mount options associated
with the filesystem. It is formatted as a comma separated list of
@ -354,6 +355,23 @@ independently from the current cygdrive prefix:</para>
</sect2>
<sect2 id="usertemp"><title>The usertemp file system type</title>
<para>On Windows, the environment variable <literal>TEMP</literal> specifies
the location of the temp folder. It serves the same purpose as the /tmp/
directory in Unix systems. In contrast to /tmp/, it is by default a
different folder for every Windows. By using the special purpose usertemp
file system, that temp folder can be mapped to /tmp/. This is particularly
useful in setups where the administrator wants to write-protect the entire
Cygwin directory. The usertemp file system can be configured in /etc/fstab
like this:</para>
<screen>
none /tmp usertemp binary,posix=0 0 0
</screen>
</sect2>
<sect2 id="pathnames-symlinks"><title>Symbolic links</title>
<para>Symbolic links are not present and supported on Windows until Windows