From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
klibc@zytor.com, Al Viro <viro@ftp.linux.org.uk>,
hpa@zytor.com, miltonm@bga.com
Subject: [PATCH] initramfs: CPIO unpacking fix
Date: Fri, 07 Apr 2006 10:33:20 -0700 [thread overview]
Message-ID: <4436A260.9070603@zytor.com> (raw)
In-Reply-To: <20060217160621.99b0ffd4.mikey@neuling.org>
Unlink files, symlinks, FIFOs, devices etc. (except directories) before
writing them when extracting CPIOs. This stops weird behaviour like:
1) writing through symlinks created in earlier CPIOs. eg foo->bar in
the first CPIO. Having foo as a non-link in a subsequent CPIO,
results in bar being written and foo remaining as a symlink.
2) if the first version of file foo is larger than foo in a
subsequent CPIO, we end up with a mix of the two. ie. neither
the first or second version of /foo.
3) special files like devices, fifo etc. can't be overwritten in
subsequent CPIOS.
With this, the kernel will more closely replicate
for i in *.cpio; do cpio --extract --unconditional < $i ; done
This is a change but it's regarded as fixing broken functionality.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
init/initramfs.c | 3 +++
1 files changed, 3 insertions(+)
Index: linux-2.6.15/init/initramfs.c
===================================================================
--- linux-2.6.15.orig/init/initramfs.c
+++ linux-2.6.15/init/initramfs.c
@@ -249,6 +249,7 @@ static int __init do_name(void)
if (dry_run)
return 0;
if (S_ISREG(mode)) {
+ sys_unlink(collected);
if (maybe_link() >= 0) {
wfd = sys_open(collected, O_WRONLY|O_CREAT, mode);
if (wfd >= 0) {
@@ -263,6 +264,7 @@ static int __init do_name(void)
sys_chmod(collected, mode);
} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
S_ISFIFO(mode) || S_ISSOCK(mode)) {
+ sys_unlink(collected);
if (maybe_link() == 0) {
sys_mknod(collected, mode, rdev);
sys_chown(collected, uid, gid);
@@ -291,6 +293,7 @@ static int __init do_copy(void)
static int __init do_symlink(void)
{
collected[N_ALIGN(name_len) + body_len] = '\0';
+ sys_unlink(collected);
sys_symlink(collected + N_ALIGN(name_len), collected);
sys_lchown(collected, uid, gid);
state = SkipIt;
prev parent reply other threads:[~2006-04-07 17:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-16 7:37 [PATCH] Chained CPIOs writing to the same file bug Michael Neuling
[not found] ` <20060217160621.99b0ffd4.mikey@neuling.org>
2006-02-21 23:45 ` [PATCH] initramfs: multiple CPIO unpacking fix Michael Neuling
2006-02-22 2:14 ` [klibc] " Jeff Bailey
2006-02-22 2:17 ` H. Peter Anvin
2006-03-22 6:12 ` [PATCH] initramfs: " Michael Neuling
2006-03-22 7:14 ` Jeff Garzik
2006-03-22 16:05 ` [klibc] " H. Peter Anvin
2006-03-22 22:23 ` Rob Landley
2006-03-22 23:22 ` Jeff Garzik
2006-04-07 17:33 ` H. Peter Anvin [this message]
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