include/linux/kmod.h

   1 #ifndef __LINUX_KMOD_H__
   2 #define __LINUX_KMOD_H__
   3
   4 /*
   5  *      include/linux/kmod.h
   6  *
   7  *      This program is free software; you can redistribute it and/or modify
   8  *      it under the terms of the GNU General Public License as published by
   9  *      the Free Software Foundation; either version 2 of the License, or
  10  *      (at your option) any later version.
  11  *
  12  *      This program is distributed in the hope that it will be useful,
  13  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *      GNU General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License
  18  *      along with this program; if not, write to the Free Software
  19  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <linux/gfp.h>
  23 #include <linux/stddef.h>
  24 #include <linux/errno.h>
  25 #include <linux/compiler.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/sysctl.h>
  28
  29 #define KMOD_PATH_LEN 256
  30
  31 #ifdef CONFIG_MODULES
  32 extern char modprobe_path[]; /* for sysctl */
  33 /* modprobe exit status on success, -ve on error.  Return value
  34  * usually useless though. */
  35 extern __printf(2, 3)
  36 int __request_module(bool wait, const char *name, ...);
  37 #define request_module(mod...) __request_module(true, mod)
  38 #define request_module_nowait(mod...) __request_module(false, mod)
  39 #define try_then_request_module(x, mod...) \
  40         ((x) ?: (__request_module(true, mod), (x)))
  41 #else
  42 static inline int request_module(const char *name, ...) { return -ENOSYS; }
  43 static inline int request_module_nowait(const char *name, ...) { return -ENOSYS; }
  44 #define try_then_request_module(x, mod...) (x)
  45 #endif
  46
  47
  48 struct cred;
  49 struct file;
  50
  51 enum umh_wait {
  52         UMH_NO_WAIT = -1,       /* don't wait at all */
  53         UMH_WAIT_EXEC = 0,      /* wait for the exec, but not the process */
  54         UMH_WAIT_PROC = 1,      /* wait for the process to complete */
  55 };
  56
  57 struct subprocess_info {
  58         struct work_struct work;
  59         struct completion *complete;
  60         char *path;
  61         char **argv;
  62         char **envp;
  63         enum umh_wait wait;
  64         int retval;
  65         int (*init)(struct subprocess_info *info, struct cred *new);
  66         void (*cleanup)(struct subprocess_info *info);
  67         void *data;
  68 };
  69
  70 /* Allocate a subprocess_info structure */
  71 struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
  72                                                   char **envp, gfp_t gfp_mask);
  73
  74 /* Set various pieces of state into the subprocess_info structure */
  75 void call_usermodehelper_setfns(struct subprocess_info *info,
  76                     int (*init)(struct subprocess_info *info, struct cred *new),
  77                     void (*cleanup)(struct subprocess_info *info),
  78                     void *data);
  79
  80 /* Actually execute the sub-process */
  81 int call_usermodehelper_exec(struct subprocess_info *info, enum umh_wait wait);
  82
  83 /* Free the subprocess_info. This is only needed if you're not going
  84    to call call_usermodehelper_exec */
  85 void call_usermodehelper_freeinfo(struct subprocess_info *info);
  86
  87 static inline int
  88 call_usermodehelper_fns(char *path, char **argv, char **envp,
  89                         enum umh_wait wait,
  90                         int (*init)(struct subprocess_info *info, struct cred *new),
  91                         void (*cleanup)(struct subprocess_info *), void *data)
  92 {
  93         struct subprocess_info *info;
  94         gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
  95
  96         info = call_usermodehelper_setup(path, argv, envp, gfp_mask);
  97
  98         if (info == NULL)
  99                 return -ENOMEM;
 100
 101         call_usermodehelper_setfns(info, init, cleanup, data);
 102
 103         return call_usermodehelper_exec(info, wait);
 104 }
 105
 106 static inline int
 107 call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait)
 108 {
 109         return call_usermodehelper_fns(path, argv, envp, wait,
 110                                        NULL, NULL, NULL);
 111 }
 112
 113 extern struct ctl_table usermodehelper_table[];
 114
 115 enum umh_disable_depth {
 116         UMH_ENABLED = 0,
 117         UMH_FREEZING,
 118         UMH_DISABLED,
 119 };
 120
 121 extern void usermodehelper_init(void);
 122
 123 extern int __usermodehelper_disable(enum umh_disable_depth depth);
 124 extern void __usermodehelper_set_disable_depth(enum umh_disable_depth depth);
 125
 126 static inline int usermodehelper_disable(void)
 127 {
 128         return __usermodehelper_disable(UMH_DISABLED);
 129 }
 130
 131 static inline void usermodehelper_enable(void)
 132 {
 133         __usermodehelper_set_disable_depth(UMH_ENABLED);
 134 }
 135
 136 extern int usermodehelper_read_trylock(void);
 137 extern long usermodehelper_read_lock_wait(long timeout);
 138 extern void usermodehelper_read_unlock(void);
 139
 140 #endif /* __LINUX_KMOD_H__ */