alistair23-linux/include/linux/umh.h
Taehee Yoo 73ab1cb2de umh: add exit routine for UMH process
A UMH process which is created by the fork_usermode_blob() such as
bpfilter needs to release members of the umh_info when process is
terminated.
But the do_exit() does not release members of the umh_info. hence module
which uses UMH needs own code to detect whether UMH process is
terminated or not.
But this implementation needs extra code for checking the status of
UMH process. it eventually makes the code more complex.

The new PF_UMH flag is added and it is used to identify UMH processes.
The exit_umh() does not release members of the umh_info.
Hence umh_info->cleanup callback should release both members of the
umh_info and the private data.

Suggested-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-11 18:05:40 -08:00

85 lines
2.3 KiB
C

#ifndef __LINUX_UMH_H__
#define __LINUX_UMH_H__
#include <linux/gfp.h>
#include <linux/stddef.h>
#include <linux/errno.h>
#include <linux/compiler.h>
#include <linux/workqueue.h>
#include <linux/sysctl.h>
struct cred;
struct file;
#define UMH_NO_WAIT 0 /* don't wait at all */
#define UMH_WAIT_EXEC 1 /* wait for the exec, but not the process */
#define UMH_WAIT_PROC 2 /* wait for the process to complete */
#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */
struct subprocess_info {
struct work_struct work;
struct completion *complete;
const char *path;
char **argv;
char **envp;
struct file *file;
int wait;
int retval;
pid_t pid;
int (*init)(struct subprocess_info *info, struct cred *new);
void (*cleanup)(struct subprocess_info *info);
void *data;
} __randomize_layout;
extern int
call_usermodehelper(const char *path, char **argv, char **envp, int wait);
extern struct subprocess_info *
call_usermodehelper_setup(const char *path, char **argv, char **envp,
gfp_t gfp_mask,
int (*init)(struct subprocess_info *info, struct cred *new),
void (*cleanup)(struct subprocess_info *), void *data);
struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
int (*init)(struct subprocess_info *info, struct cred *new),
void (*cleanup)(struct subprocess_info *), void *data);
struct umh_info {
const char *cmdline;
struct file *pipe_to_umh;
struct file *pipe_from_umh;
struct list_head list;
void (*cleanup)(struct umh_info *info);
pid_t pid;
};
int fork_usermode_blob(void *data, size_t len, struct umh_info *info);
extern int
call_usermodehelper_exec(struct subprocess_info *info, int wait);
extern struct ctl_table usermodehelper_table[];
enum umh_disable_depth {
UMH_ENABLED = 0,
UMH_FREEZING,
UMH_DISABLED,
};
extern int __usermodehelper_disable(enum umh_disable_depth depth);
extern void __usermodehelper_set_disable_depth(enum umh_disable_depth depth);
static inline int usermodehelper_disable(void)
{
return __usermodehelper_disable(UMH_DISABLED);
}
static inline void usermodehelper_enable(void)
{
__usermodehelper_set_disable_depth(UMH_ENABLED);
}
extern int usermodehelper_read_trylock(void);
extern long usermodehelper_read_lock_wait(long timeout);
extern void usermodehelper_read_unlock(void);
#endif /* __LINUX_UMH_H__ */