Commit a2071573 authored by Jia He's avatar Jia He Committed by Chuck Lever
Browse files

sysctl: introduce new proc handler proc_dobool 



This is to let bool variable could be correctly displayed in
big/little endian sysctl procfs. sizeof(bool) is arch dependent,
proc_dobool should work in all arches.

Suggested-by: default avatarPan Xinhui <xinhui@linux.vnet.ibm.com>
Signed-off-by: default avatarJia He <hejianet@gmail.com>
[thuth: rebased the patch to the current kernel version]
Signed-off-by: default avatarThomas Huth <thuth@redhat.com>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 5c117207

include/linux/sysctl.h

+2 −0
Original line number Diff line number Diff line
@@ -48,6 +48,8 @@ typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer, 
		size_t *lenp, loff_t *ppos);



int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);

int proc_dobool(struct ctl_table *table, int write, void *buffer,

		size_t *lenp, loff_t *ppos);

int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);

int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);

int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);

kernel/sysctl.c

+42 −0
Original line number Diff line number Diff line
@@ -536,6 +536,21 @@ static void proc_put_char(void **buf, size_t *size, char c) 
	}

}



static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,

				int *valp,

				int write, void *data)

{

	if (write) {

		*(bool *)valp = *lvalp;

	} else {

		int val = *(bool *)valp;



		*lvalp = (unsigned long)val;

		*negp = false;

	}

	return 0;

}



static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,

				 int *valp,

				 int write, void *data)
@@ -798,6 +813,26 @@ static int do_proc_douintvec(struct ctl_table *table, int write, 
				   buffer, lenp, ppos, conv, data);

}



/**

 * proc_dobool - read/write a bool

 * @table: the sysctl table

 * @write: %TRUE if this is a write to the sysctl file

 * @buffer: the user buffer

 * @lenp: the size of the user buffer

 * @ppos: file position

 *

 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer

 * values from/to the user buffer, treated as an ASCII string.

 *

 * Returns 0 on success.

 */

int proc_dobool(struct ctl_table *table, int write, void *buffer,

		size_t *lenp, loff_t *ppos)

{

	return do_proc_dointvec(table, write, buffer, lenp, ppos,

				do_proc_dobool_conv, NULL);

}



/**

 * proc_dointvec - read a vector of integers

 * @table: the sysctl table
@@ -1630,6 +1665,12 @@ int proc_dostring(struct ctl_table *table, int write, 
	return -ENOSYS;

}



int proc_dobool(struct ctl_table *table, int write,

		void *buffer, size_t *lenp, loff_t *ppos)

{

	return -ENOSYS;

}



int proc_dointvec(struct ctl_table *table, int write,

		  void *buffer, size_t *lenp, loff_t *ppos)

{
@@ -3425,6 +3466,7 @@ int __init sysctl_init(void) 
 * No sense putting this after each symbol definition, twice,

 * exception granted :-)

 */

EXPORT_SYMBOL(proc_dobool);

EXPORT_SYMBOL(proc_dointvec);

EXPORT_SYMBOL(proc_douintvec);

EXPORT_SYMBOL(proc_dointvec_jiffies);