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authorEric W. Biederman <ebiederm@xmission.com>2020-02-19 10:37:15 -0600
committerEric W. Biederman <ebiederm@xmission.com>2020-02-28 12:04:33 -0600
commit76313c70c52f930af4afd21684509ca52297ea71 (patch)
tree831848faa7388eb7b7cc5e0c03cfbfff1d9f724d /arch/um
parentaf1abab986b85fdeb3e98c037988cfa4bf9d4018 (diff)
downloadlinux-76313c70c52f930af4afd21684509ca52297ea71.tar.bz2
uml: Create a private mount of proc for mconsole
The mconsole code only ever accesses proc for the initial pid namespace. Instead of depending upon the proc_mnt which is for proc_flush_task have uml create it's own mount of proc instead. This allows proc_flush_task to evolve and remove the need for having a proc_mnt to do it's job. Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/drivers/mconsole_kern.c28
1 files changed, 27 insertions, 1 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index e8f5c81c2c6c..30575bd92975 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -36,6 +36,8 @@
#include "mconsole_kern.h"
#include <os.h>
+static struct vfsmount *proc_mnt = NULL;
+
static int do_unlink_socket(struct notifier_block *notifier,
unsigned long what, void *data)
{
@@ -123,7 +125,7 @@ void mconsole_log(struct mc_request *req)
void mconsole_proc(struct mc_request *req)
{
- struct vfsmount *mnt = init_pid_ns.proc_mnt;
+ struct vfsmount *mnt = proc_mnt;
char *buf;
int len;
struct file *file;
@@ -134,6 +136,10 @@ void mconsole_proc(struct mc_request *req)
ptr += strlen("proc");
ptr = skip_spaces(ptr);
+ if (!mnt) {
+ mconsole_reply(req, "Proc not available", 1, 0);
+ goto out;
+ }
file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
if (IS_ERR(file)) {
mconsole_reply(req, "Failed to open file", 1, 0);
@@ -683,6 +689,24 @@ void mconsole_stack(struct mc_request *req)
with_console(req, stack_proc, to);
}
+static int __init mount_proc(void)
+{
+ struct file_system_type *proc_fs_type;
+ struct vfsmount *mnt;
+
+ proc_fs_type = get_fs_type("proc");
+ if (!proc_fs_type)
+ return -ENODEV;
+
+ mnt = kern_mount(proc_fs_type);
+ put_filesystem(proc_fs_type);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+
+ proc_mnt = mnt;
+ return 0;
+}
+
/*
* Changed by mconsole_setup, which is __setup, and called before SMP is
* active.
@@ -696,6 +720,8 @@ static int __init mconsole_init(void)
int err;
char file[UNIX_PATH_MAX];
+ mount_proc();
+
if (umid_file_name("mconsole", file, sizeof(file)))
return -1;
snprintf(mconsole_socket_name, sizeof(file), "%s", file);