[PATCH] lib/bitmap.c: rewrite __bitmap_parse && __bitmap_parselist

From: Pan Xinhui
Date: Tue Jun 30 2015 - 04:04:28 EST


add __bitmap_parse_common to match any contents and return expected result.

as __bitmap_parse_common need NULL-terminated string, we alloc a new buf.

this patch also fix some parse issues in __bitmap_parselist.
now it can handle grouping errors with input like " ", ",", etc.

Signed-off-by: xinhuix.pan <xinhuix.pan@xxxxxxxxx>
---
lib/bitmap.c | 232 ++++++++++++++++++++++++++++++++---------------------------
1 file changed, 128 insertions(+), 104 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 64c0926..bc53c4f 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -16,6 +16,8 @@
#include <asm/page.h>
#include <asm/uaccess.h>
+#include <linux/parser.h>
+#include <linux/slab.h>
/*
* bitmaps provide an array of bits, implemented using an an
* array of unsigned longs. The number of valid bits in a
@@ -331,6 +333,58 @@ again:
EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
/*
+ * __bitmap_parse_common - parse expected number from buf
+ * Return 0 on success.
+ * there two patterns.
+ * if buf's contents did not match any of them, reutrn equivalent error.
+ * Notice buf's contents may be changed.
+ */
+static int __bitmap_parse_common(char *buf, unsigned int buflen,
+ unsigned long *a, unsigned long *b)
+{
+ int ret;
+ int token;
+ const match_table_t table = {
+ {
+ .token = 1,
+ .pattern = "%u",
+ },
+ {
+ .token = 2,
+ .pattern = "%u-%u",
+ },
+ {
+ .token = 0,
+ .pattern = NULL,
+ }
+ };
+ substring_t substr[MAX_OPT_ARGS];
+
+ if (!buflen || !a)
+ return -EINVAL;
+
+ token = match_token((char *)buf, table, substr);
+ switch (token) {
+ case 1:
+ *substr[0].to = '\0';
+ ret = kstrtoul(substr[0].from, 0, a);
+ if (b)
+ *b = *a;
+ break;
+ case 2:
+ *substr[0].to = '\0';
+ *substr[1].to = '\0';
+ ret = kstrtoul(substr[0].from, 0, a);
+ ret |= b ? kstrtoul(substr[1].from, 0, b) : -EINVAL;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ return ret;
+}
+
+/*
* Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
* second version by Paul Jackson, third by Joe Korty.
*/
@@ -359,57 +413,44 @@ int __bitmap_parse(const char *buf, unsigned int buflen,
int is_user, unsigned long *maskp,
int nmaskbits)
{
- int c, old_c, totaldigits, ndigits, nchunks, nbits;
+ int nchunks, nbits, ret;
+ unsigned long a;
u32 chunk;
const char __user __force *ubuf = (const char __user __force *)buf;
+ char *kbuf, *endp;
+
+ if (!buflen)
+ return -EINVAL;
+ kbuf = kmalloc(buflen + 1, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+ if (is_user) {
+ if (copy_from_user(kbuf, ubuf, buflen) != 0) {
+ kfree(kbuf);
+ return -EFAULT;
+ }
+ } else
+ memcpy(kbuf, buf, buflen);
+ kbuf[buflen] = '\0';
+ buf = strim(kbuf);
bitmap_zero(maskp, nmaskbits);
- nchunks = nbits = totaldigits = c = 0;
+ nchunks = nbits = 0;
do {
- chunk = ndigits = 0;
-
- /* Get the next chunk of the bitmap */
- while (buflen) {
- old_c = c;
- if (is_user) {
- if (__get_user(c, ubuf++))
- return -EFAULT;
- }
- else
- c = *buf++;
- buflen--;
- if (isspace(c))
- continue;
-
- /*
- * If the last character was a space and the current
- * character isn't '\0', we've got embedded whitespace.
- * This is a no-no, so throw an error.
- */
- if (totaldigits && c && isspace(old_c))
- return -EINVAL;
-
- /* A '\0' or a ',' signal the end of the chunk */
- if (c == '\0' || c == ',')
- break;
-
- if (!isxdigit(c))
- return -EINVAL;
-
- /*
- * Make sure there are at least 4 free bits in 'chunk'.
- * If not, this hexdigit will overflow 'chunk', so
- * throw an error.
- */
- if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
- return -EOVERFLOW;
-
- chunk = (chunk << 4) | hex_to_bin(c);
- ndigits++; totaldigits++;
+ endp = strchr(buf, ',');
+ if (endp)
+ *endp = '\0';
+ ret = __bitmap_parse_common((char *)buf, strlen(buf), &a, NULL);
+ if (ret)
+ break;
+ buf = endp + 1;
+
+ if (unlikely(a > U32_MAX)) {
+ ret = -ERANGE;
+ break;
}
- if (ndigits == 0)
- return -EINVAL;
+ chunk = (u32)a;
if (nchunks == 0 && chunk == 0)
continue;
@@ -417,11 +458,13 @@ int __bitmap_parse(const char *buf, unsigned int buflen,
*maskp |= chunk;
nchunks++;
nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
- if (nbits > nmaskbits)
- return -EOVERFLOW;
- } while (buflen && c == ',');
-
- return 0;
+ if (nbits > nmaskbits) {
+ ret = -EOVERFLOW;
+ break;
+ }
+ } while (endp);
+ kfree(kbuf);
+ return ret;
}
EXPORT_SYMBOL(__bitmap_parse);
@@ -503,70 +546,51 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
int is_user, unsigned long *maskp,
int nmaskbits)
{
- unsigned a, b;
- int c, old_c, totaldigits;
+ unsigned long a, b;
+ int ret = 0;
const char __user __force *ubuf = (const char __user __force *)buf;
- int exp_digit, in_range;
+ char *kbuf, *endp;
+
+ if (!buflen)
+ return -EINVAL;
+ kbuf = kmalloc(buflen + 1, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+ if (is_user) {
+ if (copy_from_user(kbuf, ubuf, buflen) != 0) {
+ kfree(kbuf);
+ return -EFAULT;
+ }
+ } else
+ memcpy(kbuf, buf, buflen);
+ kbuf[buflen] = '\0';
+ buf = strim(kbuf);
- totaldigits = c = 0;
bitmap_zero(maskp, nmaskbits);
do {
- exp_digit = 1;
- in_range = 0;
- a = b = 0;
-
- /* Get the next cpu# or a range of cpu#'s */
- while (buflen) {
- old_c = c;
- if (is_user) {
- if (__get_user(c, ubuf++))
- return -EFAULT;
- } else
- c = *buf++;
- buflen--;
- if (isspace(c))
- continue;
-
- /*
- * If the last character was a space and the current
- * character isn't '\0', we've got embedded whitespace.
- * This is a no-no, so throw an error.
- */
- if (totaldigits && c && isspace(old_c))
- return -EINVAL;
-
- /* A '\0' or a ',' signal the end of a cpu# or range */
- if (c == '\0' || c == ',')
- break;
-
- if (c == '-') {
- if (exp_digit || in_range)
- return -EINVAL;
- b = 0;
- in_range = 1;
- exp_digit = 1;
- continue;
- }
-
- if (!isdigit(c))
- return -EINVAL;
-
- b = b * 10 + (c - '0');
- if (!in_range)
- a = b;
- exp_digit = 0;
- totaldigits++;
+ endp = strchr(buf, ',');
+ if (endp)
+ *endp = '\0';
+ ret = __bitmap_parse_common((char *)buf, strlen(buf), &a, &b);
+ if (ret)
+ break;
+ buf = endp + 1;
+
+ if (!(a <= b)) {
+ ret = -EINVAL;
+ break;
+ }
+ if (b >= nmaskbits) {
+ ret = -ERANGE;
+ break;
}
- if (!(a <= b))
- return -EINVAL;
- if (b >= nmaskbits)
- return -ERANGE;
while (a <= b) {
set_bit(a, maskp);
a++;
}
- } while (buflen && c == ',');
- return 0;
+ } while (endp);
+ kfree(kbuf);
+ return ret;
}
int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
--
1.9.1
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