There as been no easy way to wrap the default sysctl strategy routine
except for returning 0. Which is not always what we want. The few
instances I have seen that want different behaviour have written their own
version of sysctl_data. While not too hard it is unnecessary code and
has the potential for extra bugs.
So to make these situnations easier and make that part of sysctl
more symetric I have factord sysctl_data out of do_sysctl_strategy
and exported as a function everyone can use.
Further having sysctl_data be an explicit function makes checking
for badly formed sysctl tables much easier.
Signed-off-by: Eric W. Biederman <[EMAIL PROTECTED]>
---
include/linux/sysctl.h | 1 +
kernel/sysctl.c | 66 +++++++++++++++++++++++++++++++++--------------
2 files changed, 47 insertions(+), 20 deletions(-)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index f73be4c..5ca510b 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -972,6 +972,7 @@ extern int do_sysctl_strategy (struct ctl_table *table,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen);
+extern ctl_handler sysctl_data;
extern ctl_handler sysctl_string;
extern ctl_handler sysctl_intvec;
extern ctl_handler sysctl_jiffies;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6723f92..cf4c632 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1406,7 +1406,6 @@ int do_sysctl_strategy (struct ctl_table *table,
void __user *newval, size_t newlen)
{
int op = 0, rc;
- size_t len;
if (oldval)
op |= 004;
@@ -1427,25 +1426,10 @@ int do_sysctl_strategy (struct ctl_table *table,
/* If there is no strategy routine, or if the strategy returns
* zero, proceed with automatic r/w */
if (table->data && table->maxlen) {
- if (oldval && oldlenp) {
- if (get_user(len, oldlenp))
- return -EFAULT;
- if (len) {
- if (len > table->maxlen)
- len = table->maxlen;
- if(copy_to_user(oldval, table->data, len))
- return -EFAULT;
- if(put_user(len, oldlenp))
- return -EFAULT;
- }
- }
- if (newval && newlen) {
- len = newlen;
- if (len > table->maxlen)
- len = table->maxlen;
- if(copy_from_user(table->data, newval, len))
- return -EFAULT;
- }
+ rc = sysctl_data(table, name, nlen, oldval, oldlenp,
+ newval, newlen);
+ if (rc < 0)
+ return rc;
}
return 0;
}
@@ -2344,6 +2328,40 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table
*table, int write,
* General sysctl support routines
*/
+/* The generic sysctl data routine (used if no strategy routine supplied) */
+int sysctl_data(struct ctl_table *table, int __user *name, int nlen,
+ void __user *oldval, size_t __user *oldlenp,
+ void __user *newval, size_t newlen)
+{
+ size_t len;
+
+ /* Get out of I don't have a variable */
+ if (!table->data || !table->maxlen)
+ return -ENOTDIR;
+
+ if (oldval && oldlenp) {
+ if (get_user(len, oldlenp))
+ return -EFAULT;
+ if (len) {
+ if (len > table->maxlen)
+ len = table->maxlen;
+ if (copy_to_user(oldval, table->data, len))
+ return -EFAULT;
+ if (put_user(len, oldlenp))
+ return -EFAULT;
+ }
+ }
+
+ if (newval && newlen) {
+ if (newlen > table->maxlen)
+ newlen = table->maxlen;
+
+ if (copy_from_user(table->data, newval, newlen))
+ return -EFAULT;
+ }
+ return 1;
+}
+
/* The generic string strategy routine: */
int sysctl_string(struct ctl_table *table, int __user *name, int nlen,
void __user *oldval, size_t __user *oldlenp,
@@ -2532,6 +2550,13 @@ out:
return -ENOSYS;
}
+int sysctl_data(struct ctl_table *table, int __user *name, int nlen,
+ void __user *oldval, size_t __user *oldlenp,
+ void __user *newval, size_t newlen)
+{
+ return -ENOSYS;
+}
+
int sysctl_string(struct ctl_table *table, int __user *name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
@@ -2579,4 +2604,5 @@ EXPORT_SYMBOL(sysctl_intvec);
EXPORT_SYMBOL(sysctl_jiffies);
EXPORT_SYMBOL(sysctl_ms_jiffies);
EXPORT_SYMBOL(sysctl_string);
+EXPORT_SYMBOL(sysctl_data);
EXPORT_SYMBOL(unregister_sysctl_table);
--
1.5.1.1.181.g2de0
-
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