nsm_use_hostnames is a module parameter and it will be exported to sysctl
procfs. This is to let user sometimes change it from userspace. But the
minimal unit for sysctl procfs read/write it sizeof(int).
In big endian system, the converting from/to bool to/from int will cause
error for proc items.
This patch introduces a new proc handler proc_dobool for nsm_use_hostnames.
Changes:
v5: Fix compilation error when CONFIG_PROC_SYSCTL is not set
v4: Change (u8 *) to (bool *)
v3: Introduce a new proc handler proc_dou8vec(suggested by Xinhui Pan)
v2: Change extern type in lockd.h
The test case I used:
/***************************************************************/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysctl.h>
bool __read_mostly nsm_use_hostnames;
module_param(nsm_use_hostnames, bool, 0644);
static struct ctl_table my_sysctl[] = {
{
.procname = "nsm_use_hostnames",
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{}
};
static struct ctl_table my_root[] = {
{
.procname = "mysysctl",
.mode = 0555,
.child = my_sysctl,
},
{}
};
static struct ctl_table_header * my_ctl_header;
static int __init sysctl_exam_init(void)
{
my_ctl_header = register_sysctl_table(&my_root);
if (my_ctl_header == NULL)
printk("error regiester sysctl");
return 0;
}
static void __exit sysctl_exam_exit(void)
{
unregister_sysctl_table(my_ctl_header);
}
module_init(sysctl_exam_init);
module_exit(sysctl_exam_exit);
MODULE_LICENSE("GPL");
/****************************************************************/
[root@bigendian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
[root@bigendian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
16777216
After I change the proc_dointvec to new handler proc_dou8vec with the
patch:
[root@bigendian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
[root@bigendian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
1
In little endian system, there is no such issue.
Already tested in both of big and little endian(ppc64 and ppc64le)
Jia He (2):
sysctl: introduce new proc handler proc_dobool
lockd: change the proc_handler for nsm_use_hostnames
fs/lockd/svc.c | 2 +-
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 44 insertions(+), 1 deletion(-)
--
2.5.5
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: Pan Xinhui <[email protected]>
Signed-off-by: Jia He <[email protected]>
---
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index adf4e51..255a9c7 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write,
extern int proc_dostring(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
+extern int proc_dobool(struct ctl_table *, int,
+ void __user *, size_t *, loff_t *);
extern int proc_dointvec(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_douintvec(struct ctl_table *, int,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 706309f..c4bec65 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c)
return 0;
}
+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;
+ }
+ return 0;
+}
+
static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
@@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write,
}
/**
+ * 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 __user *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
* @write: %TRUE if this is a write to the sysctl file
@@ -2885,6 +2919,12 @@ int proc_dostring(struct ctl_table *table, int write,
return -ENOSYS;
}
+int proc_dobool(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ return -ENOSYS;
+}
+
int proc_dointvec(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
@@ -2941,6 +2981,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
* 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);
--
2.5.5
在 2016/12/15 15:24, Jia He 写道:
> nsm_use_hostnames is a module parameter and it will be exported to sysctl
> procfs. This is to let user sometimes change it from userspace. But the
> minimal unit for sysctl procfs read/write it sizeof(int).
^^^is^^^
> In big endian system, the converting from/to bool to/from int will cause
> error for proc items.
>
> This patch use a new proc_handler proc_dobool to fixe it.
^^^fix^^^
> Signed-off-by: Jia He <[email protected]>
> ---
other than that is okay for me.
Reviewed-by: Pan Xinhui <[email protected]>
> fs/lockd/svc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index fc4084e..bd6fcf9 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -561,7 +561,7 @@ static struct ctl_table nlm_sysctls[] = {
> .data = &nsm_use_hostnames,
> .maxlen = sizeof(int),
> .mode = 0644,
> - .proc_handler = proc_dointvec,
> + .proc_handler = proc_dobool,
> },
> {
> .procname = "nsm_local_state",
>
在 2016/12/15 15:24, Jia He 写道:
> 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: Pan Xinhui <[email protected]>
> Signed-off-by: Jia He <[email protected]>
> ---
> include/linux/sysctl.h | 2 ++
> kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
>
Reviewed-by: Pan Xinhui <[email protected]>
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index adf4e51..255a9c7 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write,
>
> extern int proc_dostring(struct ctl_table *, int,
> void __user *, size_t *, loff_t *);
> +extern int proc_dobool(struct ctl_table *, int,
> + void __user *, size_t *, loff_t *);
> extern int proc_dointvec(struct ctl_table *, int,
> void __user *, size_t *, loff_t *);
> extern int proc_douintvec(struct ctl_table *, int,
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 706309f..c4bec65 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c)
> return 0;
> }
>
> +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;
> + }
> + return 0;
> +}
> +
> static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
> int *valp,
> int write, void *data)
> @@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write,
> }
>
> /**
> + * 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 __user *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
> * @write: %TRUE if this is a write to the sysctl file
> @@ -2885,6 +2919,12 @@ int proc_dostring(struct ctl_table *table, int write,
> return -ENOSYS;
> }
>
> +int proc_dobool(struct ctl_table *table, int write,
> + void __user *buffer, size_t *lenp, loff_t *ppos)
> +{
> + return -ENOSYS;
> +}
> +
> int proc_dointvec(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp, loff_t *ppos)
> {
> @@ -2941,6 +2981,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
> * 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);
>
nsm_use_hostnames is a module parameter and it will be exported to sysctl
procfs. This is to let user sometimes change it from userspace. But the
minimal unit for sysctl procfs read/write it sizeof(int).
In big endian system, the converting from/to bool to/from int will cause
error for proc items.
This patch use a new proc_handler proc_dobool to fixe it.
Signed-off-by: Jia He <[email protected]>
---
fs/lockd/svc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index fc4084e..bd6fcf9 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -561,7 +561,7 @@ static struct ctl_table nlm_sysctls[] = {
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dobool,
},
{
.procname = "nsm_local_state",
--
2.5.5
Ping, any comments are welcome. Thanks
B.R.
Jia
On 15/12/2016 3:24 PM, Jia He wrote:
> nsm_use_hostnames is a module parameter and it will be exported to sysctl
> procfs. This is to let user sometimes change it from userspace. But the
> minimal unit for sysctl procfs read/write it sizeof(int).
> In big endian system, the converting from/to bool to/from int will cause
> error for proc items.
>
> This patch introduces a new proc handler proc_dobool for nsm_use_hostnames.
>
> Changes:
> v5: Fix compilation error when CONFIG_PROC_SYSCTL is not set
> v4: Change (u8 *) to (bool *)
> v3: Introduce a new proc handler proc_dou8vec(suggested by Xinhui Pan)
> v2: Change extern type in lockd.h
>
> The test case I used:
> /***************************************************************/
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/sysctl.h>
>
> bool __read_mostly nsm_use_hostnames;
> module_param(nsm_use_hostnames, bool, 0644);
>
> static struct ctl_table my_sysctl[] = {
> {
> .procname = "nsm_use_hostnames",
> .data = &nsm_use_hostnames,
> .maxlen = sizeof(int),
> .mode = 0644,
> .proc_handler = &proc_dointvec,
> },
> {}
> };
>
> static struct ctl_table my_root[] = {
> {
> .procname = "mysysctl",
> .mode = 0555,
> .child = my_sysctl,
> },
> {}
> };
>
> static struct ctl_table_header * my_ctl_header;
>
> static int __init sysctl_exam_init(void)
> {
> my_ctl_header = register_sysctl_table(&my_root);
> if (my_ctl_header == NULL)
> printk("error regiester sysctl");
>
> return 0;
> }
>
> static void __exit sysctl_exam_exit(void)
> {
> unregister_sysctl_table(my_ctl_header);
> }
>
> module_init(sysctl_exam_init);
> module_exit(sysctl_exam_exit);
> MODULE_LICENSE("GPL");
> /****************************************************************/
>
> [root@bigendian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
> [root@bigendian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
> 16777216
>
> After I change the proc_dointvec to new handler proc_dou8vec with the
> patch:
> [root@bigendian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
> [root@bigendian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
> 1
>
> In little endian system, there is no such issue.
> Already tested in both of big and little endian(ppc64 and ppc64le)
>
> Jia He (2):
> sysctl: introduce new proc handler proc_dobool
> lockd: change the proc_handler for nsm_use_hostnames
>
> fs/lockd/svc.c | 2 +-
> include/linux/sysctl.h | 2 ++
> kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 44 insertions(+), 1 deletion(-)
On Thu, Dec 15, 2016 at 03:24:20PM +0800, Jia He wrote:
> 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.
Did Alexey Debriyan agree that this dealt with his objections?
Also it'd be nice to have a sign-off from somebody that's actually
touched sysctl.c. Then I could take it through the nfsd tree if that
doesn't cause anyone trouble.
--b.
>
> Suggested-by: Pan Xinhui <[email protected]>
> Signed-off-by: Jia He <[email protected]>
> ---
> include/linux/sysctl.h | 2 ++
> kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index adf4e51..255a9c7 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write,
>
> extern int proc_dostring(struct ctl_table *, int,
> void __user *, size_t *, loff_t *);
> +extern int proc_dobool(struct ctl_table *, int,
> + void __user *, size_t *, loff_t *);
> extern int proc_dointvec(struct ctl_table *, int,
> void __user *, size_t *, loff_t *);
> extern int proc_douintvec(struct ctl_table *, int,
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 706309f..c4bec65 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c)
> return 0;
> }
>
> +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;
> + }
> + return 0;
> +}
> +
> static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
> int *valp,
> int write, void *data)
> @@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write,
> }
>
> /**
> + * 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 __user *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
> * @write: %TRUE if this is a write to the sysctl file
> @@ -2885,6 +2919,12 @@ int proc_dostring(struct ctl_table *table, int write,
> return -ENOSYS;
> }
>
> +int proc_dobool(struct ctl_table *table, int write,
> + void __user *buffer, size_t *lenp, loff_t *ppos)
> +{
> + return -ENOSYS;
> +}
> +
> int proc_dointvec(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp, loff_t *ppos)
> {
> @@ -2941,6 +2981,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
> * 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);
> --
> 2.5.5
On 05/01/2017 5:09 AM, J. Bruce Fields wrote:
> On Thu, Dec 15, 2016 at 03:24:20PM +0800, Jia He wrote:
>> 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.
> Did Alexey Debriyan agree that this dealt with his objections?
Hi Alexey, any thoughts? ;-)
Thanks
B.R.
Jia
> Also it'd be nice to have a sign-off from somebody that's actually
> touched sysctl.c. Then I could take it through the nfsd tree if that
> doesn't cause anyone trouble.
>
> --b.
>
>> Suggested-by: Pan Xinhui <[email protected]>
>> Signed-off-by: Jia He <[email protected]>
>> ---
>> include/linux/sysctl.h | 2 ++
>> kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 43 insertions(+)
>>
>> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
>> index adf4e51..255a9c7 100644
>> --- a/include/linux/sysctl.h
>> +++ b/include/linux/sysctl.h
>> @@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write,
>>
>> extern int proc_dostring(struct ctl_table *, int,
>> void __user *, size_t *, loff_t *);
>> +extern int proc_dobool(struct ctl_table *, int,
>> + void __user *, size_t *, loff_t *);
>> extern int proc_dointvec(struct ctl_table *, int,
>> void __user *, size_t *, loff_t *);
>> extern int proc_douintvec(struct ctl_table *, int,
>> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
>> index 706309f..c4bec65 100644
>> --- a/kernel/sysctl.c
>> +++ b/kernel/sysctl.c
>> @@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c)
>> return 0;
>> }
>>
>> +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;
>> + }
>> + return 0;
>> +}
>> +
>> static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
>> int *valp,
>> int write, void *data)
>> @@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write,
>> }
>>
>> /**
>> + * 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 __user *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
>> * @write: %TRUE if this is a write to the sysctl file
>> @@ -2885,6 +2919,12 @@ int proc_dostring(struct ctl_table *table, int write,
>> return -ENOSYS;
>> }
>>
>> +int proc_dobool(struct ctl_table *table, int write,
>> + void __user *buffer, size_t *lenp, loff_t *ppos)
>> +{
>> + return -ENOSYS;
>> +}
>> +
>> int proc_dointvec(struct ctl_table *table, int write,
>> void __user *buffer, size_t *lenp, loff_t *ppos)
>> {
>> @@ -2941,6 +2981,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
>> * 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);
>> --
>> 2.5.5