[PATCH] tar-tree: add the "tar.applyUmask" config option

[PATCH] tar-tree: add the "tar.applyUmask" config option

[Willy Tarreau]

Hi Junio, Hi Rene,

While I agreed with Linus that the very permissive file modes set in tar
archives were not particularly a problem for kernel users, I'm finding
that for some other projects it sometimes becomes really annoying, to
the point that I finally considered using a plain tar instead. This is a
shame because tar-tree is really fast an powerful, and I like its ability
to enforce permissions when those of the local dir might be wrong for
various reasons.

So I added a config option to tell tar-tree to respect the user's umask
to the files and dirs listed in the output tar file. By default, this
option is not set, of course, but once set to true, the files look somewhat
better :

$ cat .git/config
[core]
        repositoryformatversion = 0
        filemode = true

[tar]
        applyUmask = true

$ ./git-tar-tree HEAD | tar tvf -|head
-rw-r--r-- git/git        1887 2006-07-19 23:23:00 .gitignore
-rw-r--r-- git/git       18787 2006-07-19 23:23:00 COPYING
drwxr-xr-x git/git           0 2006-07-19 23:23:00 Documentation/
-rw-r--r-- git/git          52 2006-07-19 23:23:00 Documentation/.gitignore
-rw-r--r-- git/git        2463 2006-07-19 23:23:00 Documentation/Makefile
-rw-r--r-- git/git       11550 2006-07-19 23:23:00 Documentation/SubmittingPatches
-rw-r--r-- git/git         822 2006-07-19 23:23:00 Documentation/asciidoc.conf
-rwxr-xr-x git/git        1049 2006-07-19 23:23:00 Documentation/build-docdep.perl
-rw-r--r-- git/git         596 2006-07-19 23:23:00 Documentation/callouts.xsl


Let me insist on the fact that the default behaviour is unchanged.
Would you consider this for inclusion ? I've made the patch below
against <master>. Please check on your side that the doc generates
valid output, as I've never managed to install the asciidoc/xmlto
toolchain.

Please keep me CCed in replies as I'm not subscribed to the git list.

Regards,
Willy

--

>From dcc976d83c3b9c85460329932ce22547b7f5f3f9 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Wed, 19 Jul 2006 23:23:00 +0200
Subject: tar-tree: add the "tar.applyUmask" config option

For some projects, producing tar files with world-writable files
can be problematic. This change introduces a the "tar.applyUmask"
config option to make tar-tree apply the umask to the permissions
set in the tar file.

Signed-off-by: Willy Tarreau <w@1wt.eu>
---
 Documentation/config.txt |    9 +++++++++
 builtin-tar-tree.c       |   19 ++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 0b434c1..32519a9 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -208,6 +208,15 @@ showbranch.default::
 	The default set of branches for gitlink:git-show-branch[1].
 	See gitlink:git-show-branch[1].
 
+tar.applyUmask::
+	By default, git-link:git-tar-tree[1] sets file and directories modes
+	to 0666 or 0777. While this is both useful and acceptable for projects
+	such as the Linux Kernel, it might be excessive for other projects.
+	Setting this variable to true makes git-link:git-tar-tree[1] apply the
+	umask to the modes above. This should be enough for most projects, as
+	it will lead to the same permissions as git-link:git-checkout[1] would
+	use. The default is false.
+
 user.email::
 	Your email address to be recorded in any newly created commits.
 	Can be overridden by the 'GIT_AUTHOR_EMAIL' and 'GIT_COMMITTER_EMAIL'
diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index f2e48aa..f66f6ad 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -20,6 +20,7 @@ static char block[BLOCKSIZE];
 static unsigned long offset;
 
 static time_t archive_time;
+static int tar_umask;
 
 /* tries hard to write, either succeeds or dies in the attempt */
 static void reliable_write(const void *data, unsigned long size)
@@ -188,13 +189,13 @@ static void write_entry(const unsigned c
 	} else {
 		if (S_ISDIR(mode)) {
 			*header.typeflag = TYPEFLAG_DIR;
-			mode |= 0777;
+			mode |= 0777 & ~tar_umask;
 		} else if (S_ISLNK(mode)) {
 			*header.typeflag = TYPEFLAG_LNK;
 			mode |= 0777;
 		} else if (S_ISREG(mode)) {
 			*header.typeflag = TYPEFLAG_REG;
-			mode |= (mode & 0100) ? 0777 : 0666;
+			mode |= ((mode & 0100) ? 0777 : 0666) &	~tar_umask;
 		} else {
 			error("unsupported file mode: 0%o (SHA1: %s)",
 			      mode, sha1_to_hex(sha1));
@@ -293,6 +294,18 @@ static void traverse_tree(struct tree_de
 	}
 }
 
+int git_tar_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "tar.applyumask")) {
+		if (git_config_bool(var, value)) {
+			tar_umask = umask(0);
+			umask(tar_umask);
+		}
+		return 0;
+	}
+	return git_default_config(var, value);
+}
+
 static int generate_tar(int argc, const char **argv, char** envp)
 {
 	unsigned char sha1[20], tree_sha1[20];
@@ -305,7 +318,7 @@ static int generate_tar(int argc, const 
 	current_path.len = current_path.eof = 0;
 
 	setup_git_directory();
-	git_config(git_default_config);
+	git_config(git_tar_config);
 
 	switch (argc) {
 	case 3:
-- 
1.4.1

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Junio C Hamano]

Willy Tarreau <w@1wt.eu> writes:

> While I agreed with Linus that the very permissive file modes set in tar
> archives were not particularly a problem for kernel users, I'm finding
> that for some other projects it sometimes becomes really annoying, to
> the point that I finally considered using a plain tar instead. This is a
> shame because tar-tree is really fast an powerful, and I like its ability
> to enforce permissions when those of the local dir might be wrong for
> various reasons.

I do not have problem with an option to allow a non-default
behaviour in this area.  Maybe we might want to be able to set
the mask in the configuration file as well, perhaps like...

	tar.umask = user ;# use from the current process'
        tar.umask = 0    ;# same as default
        tar.umask = 002  ;# group friendly

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Johannes Schindelin]

Hi,

while at it, you could ask an explicit "--umask=<n>" flag, no?

Ciao,
Dscho

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Willy Tarreau]

On Wed, Jul 19, 2006 at 03:33:48PM -0700, Junio C Hamano wrote:
> Willy Tarreau <w@1wt.eu> writes:
> 
> > While I agreed with Linus that the very permissive file modes set in tar
> > archives were not particularly a problem for kernel users, I'm finding
> > that for some other projects it sometimes becomes really annoying, to
> > the point that I finally considered using a plain tar instead. This is a
> > shame because tar-tree is really fast an powerful, and I like its ability
> > to enforce permissions when those of the local dir might be wrong for
> > various reasons.
> 
> I do not have problem with an option to allow a non-default
> behaviour in this area.  Maybe we might want to be able to set
> the mask in the configuration file as well, perhaps like...
> 
> 	tar.umask = user ;# use from the current process'
>         tar.umask = 0    ;# same as default
>         tar.umask = 002  ;# group friendly

This is an excellent idea. I will try to find some spare time tomorrow
to implement it. I've also seen the proposal about the --umask= option.
I don't think it's absolutely necessary since the umask has little reason
to change during the repo's life, but if the implementation is obvious,
I will do it too.

Thanks for your suggestion,
Willy

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Rene Scharfe]

Hi Willy,

I kind of like the change, because it gives the user more control.
Theoretically this would not be needed, because tar can apply the
umask at extract time just fine.  In practice I can't see why we
should forbid users from creating the archives just the way they
like them, no matter what their reasoning might be.

Willy Tarreau schrieb:
> +tar.applyUmask::
> +	By default, git-link:git-tar-tree[1] sets file and directories modes
> +	to 0666 or 0777. While this is both useful and acceptable for projects
> +	such as the Linux Kernel, it might be excessive for other projects.
> +	Setting this variable to true makes git-link:git-tar-tree[1] apply the
> +	umask to the modes above. This should be enough for most projects, as
> +	it will lead to the same permissions as git-link:git-checkout[1] would
> +	use. The default is false.

Comments about why this change is needed and that it is sufficient
should go into the commit message.  For the rest of the patch:

Acked-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Willy Tarreau]

Hi Junio,

On Wed, Jul 19, 2006 at 03:33:48PM -0700, Junio C Hamano wrote:
> Willy Tarreau <w@1wt.eu> writes:
> 
> > While I agreed with Linus that the very permissive file modes set in tar
> > archives were not particularly a problem for kernel users, I'm finding
> > that for some other projects it sometimes becomes really annoying, to
> > the point that I finally considered using a plain tar instead. This is a
> > shame because tar-tree is really fast an powerful, and I like its ability
> > to enforce permissions when those of the local dir might be wrong for
> > various reasons.
> 
> I do not have problem with an option to allow a non-default
> behaviour in this area.  Maybe we might want to be able to set
> the mask in the configuration file as well, perhaps like...
> 
> 	tar.umask = user ;# use from the current process'
>         tar.umask = 0    ;# same as default
>         tar.umask = 002  ;# group friendly

Here's the new version following your suggestion above. I really liked it.
I've also added a configuration example in the doc. Once again, please
ensure that the doc generates correctly.

Thanks,
Willy


>From d8a0d2bbd2365b719a7f68edd78c77a0fd903cab Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Thu, 20 Jul 2006 11:23:40 +0200
Subject: tar-tree: add the "tar.umask" config option

By default, git-tar-tree(1) sets file and directories modes to 0666
or 0777. While this is both useful and acceptable for projects such
as the Linux Kernel, it might be excessive for other projects. With
this variable, it becomes possible to tell git-tar-tree(1) to apply
a specific umask to the modes above. The special value "user"
indicates that the user's current umask will be used. This should be
enough for most projects, as it will lead to the same permissions as
git-checkout(1) would use. The default value remains 0, which means
world read-write.

Signed-off-by: Willy Tarreau <w@1wt.eu>
---
 Documentation/config.txt       |   11 +++++++++++
 Documentation/git-tar-tree.txt |   15 ++++++++++++++-
 builtin-tar-tree.c             |   21 ++++++++++++++++++---
 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 0b434c1..f4985d4 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -208,6 +208,17 @@ showbranch.default::
 	The default set of branches for gitlink:git-show-branch[1].
 	See gitlink:git-show-branch[1].
 
+tar.umask::
+	By default, git-link:git-tar-tree[1] sets file and directories modes
+	to 0666 or 0777. While this is both useful and acceptable for projects
+	such as the Linux Kernel, it might be excessive for other projects.
+	With this variable, it becomes possible to tell
+	git-link:git-tar-tree[1] to apply a specific umask to the modes above.
+	The special value "user" indicates that the user's current umask will
+	be used. This should be enough for most projects, as it will lead to
+	the same permissions as git-link:git-checkout[1] would use. The default
+	value remains 0, which means world read-write.
+
 user.email::
 	Your email address to be recorded in any newly created commits.
 	Can be overridden by the 'GIT_AUTHOR_EMAIL' and 'GIT_COMMITTER_EMAIL'
diff --git a/Documentation/git-tar-tree.txt b/Documentation/git-tar-tree.txt
index f2675c4..7a99acf 100644
--- a/Documentation/git-tar-tree.txt
+++ b/Documentation/git-tar-tree.txt
@@ -37,7 +37,20 @@ OPTIONS
 	Instead of making a tar archive from local repository,
 	retrieve a tar archive from a remote repository.
 
-Examples
+CONFIGURATION
+-------------
+By default, file and directories modes are set to 0666 or 0777. It is
+possible to change this by setting the "umask" variable in the
+repository configuration as follows :
+
+[tar]
+        umask = 002	;# group friendly
+
+The special umask value "user" indicates that the user's current umask
+will be used instead. The default value remains 0, which means world
+readable/writable files and directories.
+
+EXAMPLES
 --------
 git tar-tree HEAD junk | (cd /var/tmp/ && tar xf -)::
 
diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index f2e48aa..e5aaded 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -20,6 +20,7 @@ static char block[BLOCKSIZE];
 static unsigned long offset;
 
 static time_t archive_time;
+static int tar_umask;
 
 /* tries hard to write, either succeeds or dies in the attempt */
 static void reliable_write(const void *data, unsigned long size)
@@ -188,13 +189,13 @@ static void write_entry(const unsigned c
 	} else {
 		if (S_ISDIR(mode)) {
 			*header.typeflag = TYPEFLAG_DIR;
-			mode |= 0777;
+			mode = (mode | 0777) & ~tar_umask;
 		} else if (S_ISLNK(mode)) {
 			*header.typeflag = TYPEFLAG_LNK;
 			mode |= 0777;
 		} else if (S_ISREG(mode)) {
 			*header.typeflag = TYPEFLAG_REG;
-			mode |= (mode & 0100) ? 0777 : 0666;
+			mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 		} else {
 			error("unsupported file mode: 0%o (SHA1: %s)",
 			      mode, sha1_to_hex(sha1));
@@ -293,6 +294,20 @@ static void traverse_tree(struct tree_de
 	}
 }
 
+int git_tar_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "tar.umask")) {
+		if (!strcmp(value, "user")) {
+			tar_umask = umask(0);
+			umask(tar_umask);
+		} else {
+			tar_umask = git_config_int(var, value);
+		}
+		return 0;
+	}
+	return git_default_config(var, value);
+}
+
 static int generate_tar(int argc, const char **argv, char** envp)
 {
 	unsigned char sha1[20], tree_sha1[20];
@@ -305,7 +320,7 @@ static int generate_tar(int argc, const 
 	current_path.len = current_path.eof = 0;
 
 	setup_git_directory();
-	git_config(git_default_config);
+	git_config(git_tar_config);
 
 	switch (argc) {
 	case 3:
-- 
1.4.1

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Rogan Dawes]

Willy Tarreau wrote:
> +int git_tar_config(const char *var, const char *value)
> +{
> +	if (!strcmp(var, "tar.umask")) {
> +		if (!strcmp(value, "user")) {
> +			tar_umask = umask(0);
> +			umask(tar_umask);
> +		} else {
> +			tar_umask = git_config_int(var, value);

Looks like you forgot:
    			umask(tar_umask);

> +		}
> +		return 0;
> +	}
> +	return git_default_config(var, value);
> +}

Or else move it to just before the "return 0;" line.

Rogan

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Willy Tarreau]

On Thu, Jul 20, 2006 at 11:44:26AM +0200, Rogan Dawes wrote:
> Willy Tarreau wrote:
> >+int git_tar_config(const char *var, const char *value)
> >+{
> >+	if (!strcmp(var, "tar.umask")) {
> >+		if (!strcmp(value, "user")) {
> >+			tar_umask = umask(0);
> >+			umask(tar_umask);
> >+		} else {
> >+			tar_umask = git_config_int(var, value);
> 
> Looks like you forgot:
>    			umask(tar_umask);

not at all : we don't want to change the process's umask, but set the
mask that will be used to position file modes in the output archive.

The reason for umask(tar_umask) above is because you cannot read the
process umask without changing it, so you have to do it twice with a
dummy value first.

> >+		}
> >+		return 0;
> >+	}
> >+	return git_default_config(var, value);
> >+}
> 
> Or else move it to just before the "return 0;" line.
> 
> Rogan

Regards,
Willy

Re: [PATCH] tar-tree: add the "tar.applyUmask" config option

[Junio C Hamano]

Thanks.