mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-31 16:38:12 +00:00
sysctl: add proc_do_large_bitmap
The new function can be used to read/write large bitmaps via /proc. A comma separated range format is used for compact output and input (e.g. 1,3-4,10-10). Writing into the file will first reset the bitmap then update it based on the given input. Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
00b7c3395a
commit
9f977fb7ae
2 changed files with 163 additions and 0 deletions
|
@ -980,6 +980,8 @@ extern int proc_doulongvec_minmax(struct ctl_table *, int,
|
|||
void __user *, size_t *, loff_t *);
|
||||
extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
|
||||
void __user *, size_t *, loff_t *);
|
||||
extern int proc_do_large_bitmap(struct ctl_table *, int,
|
||||
void __user *, size_t *, loff_t *);
|
||||
|
||||
/*
|
||||
* Register a set of sysctl names by calling register_sysctl_table
|
||||
|
|
161
kernel/sysctl.c
161
kernel/sysctl.c
|
@ -2049,6 +2049,16 @@ static size_t proc_skip_spaces(char **buf)
|
|||
return ret;
|
||||
}
|
||||
|
||||
static void proc_skip_char(char **buf, size_t *size, const char v)
|
||||
{
|
||||
while (*size) {
|
||||
if (**buf != v)
|
||||
break;
|
||||
(*size)--;
|
||||
(*buf)++;
|
||||
}
|
||||
}
|
||||
|
||||
#define TMPBUFLEN 22
|
||||
/**
|
||||
* proc_get_long - reads an ASCII formated integer from a user buffer
|
||||
|
@ -2675,6 +2685,157 @@ static int proc_do_cad_pid(struct ctl_table *table, int write,
|
|||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* proc_do_large_bitmap - read/write from/to a large bitmap
|
||||
* @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
|
||||
*
|
||||
* The bitmap is stored at table->data and the bitmap length (in bits)
|
||||
* in table->maxlen.
|
||||
*
|
||||
* We use a range comma separated format (e.g. 1,3-4,10-10) so that
|
||||
* large bitmaps may be represented in a compact manner. Writing into
|
||||
* the file will clear the bitmap then update it with the given input.
|
||||
*
|
||||
* Returns 0 on success.
|
||||
*/
|
||||
int proc_do_large_bitmap(struct ctl_table *table, int write,
|
||||
void __user *buffer, size_t *lenp, loff_t *ppos)
|
||||
{
|
||||
int err = 0;
|
||||
bool first = 1;
|
||||
size_t left = *lenp;
|
||||
unsigned long bitmap_len = table->maxlen;
|
||||
unsigned long *bitmap = (unsigned long *) table->data;
|
||||
unsigned long *tmp_bitmap = NULL;
|
||||
char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
|
||||
|
||||
if (!bitmap_len || !left || (*ppos && !write)) {
|
||||
*lenp = 0;
|
||||
return 0;
|
||||
}
|
||||
|
||||
if (write) {
|
||||
unsigned long page = 0;
|
||||
char *kbuf;
|
||||
|
||||
if (left > PAGE_SIZE - 1)
|
||||
left = PAGE_SIZE - 1;
|
||||
|
||||
page = __get_free_page(GFP_TEMPORARY);
|
||||
kbuf = (char *) page;
|
||||
if (!kbuf)
|
||||
return -ENOMEM;
|
||||
if (copy_from_user(kbuf, buffer, left)) {
|
||||
free_page(page);
|
||||
return -EFAULT;
|
||||
}
|
||||
kbuf[left] = 0;
|
||||
|
||||
tmp_bitmap = kzalloc(BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long),
|
||||
GFP_KERNEL);
|
||||
if (!tmp_bitmap) {
|
||||
free_page(page);
|
||||
return -ENOMEM;
|
||||
}
|
||||
proc_skip_char(&kbuf, &left, '\n');
|
||||
while (!err && left) {
|
||||
unsigned long val_a, val_b;
|
||||
bool neg;
|
||||
|
||||
err = proc_get_long(&kbuf, &left, &val_a, &neg, tr_a,
|
||||
sizeof(tr_a), &c);
|
||||
if (err)
|
||||
break;
|
||||
if (val_a >= bitmap_len || neg) {
|
||||
err = -EINVAL;
|
||||
break;
|
||||
}
|
||||
|
||||
val_b = val_a;
|
||||
if (left) {
|
||||
kbuf++;
|
||||
left--;
|
||||
}
|
||||
|
||||
if (c == '-') {
|
||||
err = proc_get_long(&kbuf, &left, &val_b,
|
||||
&neg, tr_b, sizeof(tr_b),
|
||||
&c);
|
||||
if (err)
|
||||
break;
|
||||
if (val_b >= bitmap_len || neg ||
|
||||
val_a > val_b) {
|
||||
err = -EINVAL;
|
||||
break;
|
||||
}
|
||||
if (left) {
|
||||
kbuf++;
|
||||
left--;
|
||||
}
|
||||
}
|
||||
|
||||
while (val_a <= val_b)
|
||||
set_bit(val_a++, tmp_bitmap);
|
||||
|
||||
first = 0;
|
||||
proc_skip_char(&kbuf, &left, '\n');
|
||||
}
|
||||
free_page(page);
|
||||
} else {
|
||||
unsigned long bit_a, bit_b = 0;
|
||||
|
||||
while (left) {
|
||||
bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
|
||||
if (bit_a >= bitmap_len)
|
||||
break;
|
||||
bit_b = find_next_zero_bit(bitmap, bitmap_len,
|
||||
bit_a + 1) - 1;
|
||||
|
||||
if (!first) {
|
||||
err = proc_put_char(&buffer, &left, ',');
|
||||
if (err)
|
||||
break;
|
||||
}
|
||||
err = proc_put_long(&buffer, &left, bit_a, false);
|
||||
if (err)
|
||||
break;
|
||||
if (bit_a != bit_b) {
|
||||
err = proc_put_char(&buffer, &left, '-');
|
||||
if (err)
|
||||
break;
|
||||
err = proc_put_long(&buffer, &left, bit_b, false);
|
||||
if (err)
|
||||
break;
|
||||
}
|
||||
|
||||
first = 0; bit_b++;
|
||||
}
|
||||
if (!err)
|
||||
err = proc_put_char(&buffer, &left, '\n');
|
||||
}
|
||||
|
||||
if (!err) {
|
||||
if (write) {
|
||||
if (*ppos)
|
||||
bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
|
||||
else
|
||||
memcpy(bitmap, tmp_bitmap,
|
||||
BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
|
||||
}
|
||||
kfree(tmp_bitmap);
|
||||
*lenp -= left;
|
||||
*ppos += *lenp;
|
||||
return 0;
|
||||
} else {
|
||||
kfree(tmp_bitmap);
|
||||
return err;
|
||||
}
|
||||
}
|
||||
|
||||
#else /* CONFIG_PROC_FS */
|
||||
|
||||
int proc_dostring(struct ctl_table *table, int write,
|
||||
|
|
Loading…
Reference in a new issue