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Fix cache handling in utils_attr_get_name. (Thanks to Bogdan for finding this bug)

edge.strict_endians
Yura Pakhuchiy 2007-09-07 15:31:33 +03:00
parent 82df6c1fea
commit ec2afb736c
1 changed files with 10 additions and 5 deletions
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15
ntfsprogs/utils.c
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@ -642,7 +642,10 @@ int utils_attr_get_name(ntfs_volume *vol, ATTR_RECORD *attr, char *buffer, int b
*
* This function has a static buffer in which it caches a section of $Bitmap.
* If the lcn, being tested, lies outside the range, the buffer will be
* refreshed.
* refreshed. @bmplcn stores offset to the first bit (in bits) stored in the
* buffer.
*
* NOTE: Be very carefull with shifts by 3 everywhere in this function.
*
* Return: 1 Cluster is in use
* 0 Cluster is free space
@ -651,8 +654,7 @@ int utils_attr_get_name(ntfs_volume *vol, ATTR_RECORD *attr, char *buffer, int b
int utils_cluster_in_use(ntfs_volume *vol, long long lcn)
{
static unsigned char buffer[512];
static long long bmplcn = -sizeof(buffer) - 1; /* Which bit of $Bitmap is in the buffer */
static long long bmplcn = -(sizeof(buffer) << 3);
int byte, bit;
ntfs_attr *attr;
@ -674,7 +676,8 @@ int utils_cluster_in_use(ntfs_volume *vol, long long lcn)
memset(buffer, 0xFF, sizeof(buffer));
bmplcn = lcn & (~((sizeof(buffer) << 3) - 1));
if (ntfs_attr_pread(attr, (bmplcn>>3), sizeof(buffer), buffer) < 0) {
if (ntfs_attr_pread(attr, (bmplcn >> 3), sizeof(buffer),
buffer) < 0) {
ntfs_log_perror("Couldn't read $Bitmap");
ntfs_attr_close(attr);
return -1;
@ -686,7 +689,9 @@ int utils_cluster_in_use(ntfs_volume *vol, long long lcn)
bit = 1 << (lcn & 7);
byte = (lcn >> 3) & (sizeof(buffer) - 1);
ntfs_log_debug("cluster = %lld, bmplcn = %lld, byte = %d, bit = %d, in use %d\n", lcn, bmplcn, byte, bit, buffer[byte] & bit);
ntfs_log_debug("cluster = %lld, bmplcn = %lld, byte = %d, bit = %d, "
"in use %d\n", lcn, bmplcn, byte, bit, buffer[byte] &
bit);
return (buffer[byte] & bit);
}