mirror of
https://github.com/linuxkit/linuxkit.git
synced 2025-11-27 03:21:49 +00:00
3bc7060843
As we released this in the beta channel, and it is a nice feature that our users love, backporting this to 4.4 so we don't have to revert it or conditionally behave differently. This is upstream Linux commits - 9a08c352d05305ca7651540c3b107da1e4e1f40b fs: add filp_clone_open API - 948b701a607f123df92ed29084413e5dd8cda2ed binfmt_misc: add persistent opened binary handler for containers Signed-off-by: Justin Cormack <justin.cormack@docker.com>
133 lines
3.6 KiB
Diff
133 lines
3.6 KiB
Diff
From 948b701a607f123df92ed29084413e5dd8cda2ed Mon Sep 17 00:00:00 2001
|
|
From: James Bottomley <James.Bottomley@HansenPartnership.com>
|
|
Date: Wed, 17 Feb 2016 16:51:16 -0800
|
|
Subject: [PATCH] binfmt_misc: add persistent opened binary handler for
|
|
containers
|
|
|
|
This patch adds a new flag 'F' to the binfmt handlers. If you pass in
|
|
'F' the binary that runs the emulation will be opened immediately and
|
|
in future, will be cloned from the open file.
|
|
|
|
The net effect is that the handler survives both changeroots and mount
|
|
namespace changes, making it easy to work with foreign architecture
|
|
containers without contaminating the container image with the
|
|
emulator.
|
|
|
|
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
|
|
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
|
|
---
|
|
fs/binfmt_misc.c | 41 +++++++++++++++++++++++++++++++++++++++--
|
|
1 file changed, 39 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
|
|
index 3a3ced7..8a108c4 100644
|
|
--- a/fs/binfmt_misc.c
|
|
+++ b/fs/binfmt_misc.c
|
|
@@ -26,6 +26,8 @@
|
|
#include <linux/fs.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
+#include "internal.h"
|
|
+
|
|
#ifdef DEBUG
|
|
# define USE_DEBUG 1
|
|
#else
|
|
@@ -43,6 +45,7 @@ enum {
|
|
#define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
|
|
#define MISC_FMT_OPEN_BINARY (1 << 30)
|
|
#define MISC_FMT_CREDENTIALS (1 << 29)
|
|
+#define MISC_FMT_OPEN_FILE (1 << 28)
|
|
|
|
typedef struct {
|
|
struct list_head list;
|
|
@@ -54,6 +57,7 @@ enum {
|
|
char *interpreter; /* filename of interpreter */
|
|
char *name;
|
|
struct dentry *dentry;
|
|
+ struct file *interp_file;
|
|
} Node;
|
|
|
|
static DEFINE_RWLOCK(entries_lock);
|
|
@@ -201,7 +205,13 @@ static int load_misc_binary(struct linux_binprm *bprm)
|
|
if (retval < 0)
|
|
goto error;
|
|
|
|
- interp_file = open_exec(iname);
|
|
+ if (fmt->flags & MISC_FMT_OPEN_FILE && fmt->interp_file) {
|
|
+ interp_file = filp_clone_open(fmt->interp_file);
|
|
+ if (!IS_ERR(interp_file))
|
|
+ deny_write_access(interp_file);
|
|
+ } else {
|
|
+ interp_file = open_exec(iname);
|
|
+ }
|
|
retval = PTR_ERR(interp_file);
|
|
if (IS_ERR(interp_file))
|
|
goto error;
|
|
@@ -285,6 +295,11 @@ static char *check_special_flags(char *sfs, Node *e)
|
|
e->flags |= (MISC_FMT_CREDENTIALS |
|
|
MISC_FMT_OPEN_BINARY);
|
|
break;
|
|
+ case 'F':
|
|
+ pr_debug("register: flag: F: open interpreter file now\n");
|
|
+ p++;
|
|
+ e->flags |= MISC_FMT_OPEN_FILE;
|
|
+ break;
|
|
default:
|
|
cont = 0;
|
|
}
|
|
@@ -543,6 +558,8 @@ static void entry_status(Node *e, char *page)
|
|
*dp++ = 'O';
|
|
if (e->flags & MISC_FMT_CREDENTIALS)
|
|
*dp++ = 'C';
|
|
+ if (e->flags & MISC_FMT_OPEN_FILE)
|
|
+ *dp++ = 'F';
|
|
*dp++ = '\n';
|
|
|
|
if (!test_bit(Magic, &e->flags)) {
|
|
@@ -590,6 +607,11 @@ static void kill_node(Node *e)
|
|
}
|
|
write_unlock(&entries_lock);
|
|
|
|
+ if ((e->flags & MISC_FMT_OPEN_FILE) && e->interp_file) {
|
|
+ filp_close(e->interp_file, NULL);
|
|
+ e->interp_file = NULL;
|
|
+ }
|
|
+
|
|
if (dentry) {
|
|
drop_nlink(d_inode(dentry));
|
|
d_drop(dentry);
|
|
@@ -698,6 +720,21 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
|
|
goto out2;
|
|
}
|
|
|
|
+ if (e->flags & MISC_FMT_OPEN_FILE) {
|
|
+ struct file *f;
|
|
+
|
|
+ f = open_exec(e->interpreter);
|
|
+ if (IS_ERR(f)) {
|
|
+ err = PTR_ERR(f);
|
|
+ pr_notice("register: failed to install interpreter file %s\n", e->interpreter);
|
|
+ simple_release_fs(&bm_mnt, &entry_count);
|
|
+ iput(inode);
|
|
+ inode = NULL;
|
|
+ goto out2;
|
|
+ }
|
|
+ e->interp_file = f;
|
|
+ }
|
|
+
|
|
e->dentry = dget(dentry);
|
|
inode->i_private = e;
|
|
inode->i_fop = &bm_entry_operations;
|
|
@@ -716,7 +753,7 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
|
|
|
|
if (err) {
|
|
kfree(e);
|
|
- return -EINVAL;
|
|
+ return err;
|
|
}
|
|
return count;
|
|
}
|
|
--
|
|
1.9.1
|
|
|