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authorEric Dumazet <edumazet@google.com>2021-03-25 11:08:13 -0700
committerDavid S. Miller <davem@davemloft.net>2021-03-25 17:39:33 -0700
commitcb9444130662c6c13022579c861098f212db2562 (patch)
tree8284fffb678daa077898d0d65f36e6e9488585e1 /kernel/sysctl.c
parentd54e1348d8ef19d5b2cd555e22ffc356f755d66e (diff)
sysctl: add proc_dou8vec_minmax()
Networking has many sysctls that could fit in one u8. This patch adds proc_dou8vec_minmax() for this purpose. Note that the .extra1 and .extra2 fields are pointing to integers, because it makes conversions easier. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 62fbd09b5dc1..90d2892ef6a3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1034,6 +1034,65 @@ int proc_douintvec_minmax(struct ctl_table *table, int write,
do_proc_douintvec_minmax_conv, &param);
}
+/**
+ * proc_dou8vec_minmax - read a vector of unsigned chars with min/max values
+ * @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(u8) unsigned chars
+ * values from/to the user buffer, treated as an ASCII string. Negative
+ * strings are not allowed.
+ *
+ * This routine will ensure the values are within the range specified by
+ * table->extra1 (min) and table->extra2 (max).
+ *
+ * Returns 0 on success or an error on write when the range check fails.
+ */
+int proc_dou8vec_minmax(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct ctl_table tmp;
+ unsigned int min = 0, max = 255U, val;
+ u8 *data = table->data;
+ struct do_proc_douintvec_minmax_conv_param param = {
+ .min = &min,
+ .max = &max,
+ };
+ int res;
+
+ /* Do not support arrays yet. */
+ if (table->maxlen != sizeof(u8))
+ return -EINVAL;
+
+ if (table->extra1) {
+ min = *(unsigned int *) table->extra1;
+ if (min > 255U)
+ return -EINVAL;
+ }
+ if (table->extra2) {
+ max = *(unsigned int *) table->extra2;
+ if (max > 255U)
+ return -EINVAL;
+ }
+
+ tmp = *table;
+
+ tmp.maxlen = sizeof(val);
+ tmp.data = &val;
+ val = *data;
+ res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
+ do_proc_douintvec_minmax_conv, &param);
+ if (res)
+ return res;
+ if (write)
+ *data = val;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
+
static int do_proc_dopipe_max_size_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
@@ -1582,6 +1641,12 @@ int proc_douintvec_minmax(struct ctl_table *table, int write,
return -ENOSYS;
}
+int proc_dou8vec_minmax(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ return -ENOSYS;
+}
+
int proc_dointvec_jiffies(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{