117 lines
2.4 KiB
C
117 lines
2.4 KiB
C
#include <sys/types.h>
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#include <stdio.h>
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#include <errno.h>
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#include <sys/acl.h>
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#include "reiserfs_lib.h"
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static inline unsigned short from32to16(unsigned int x)
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{
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/* add up 16-bit and 16-bit for 16+c bit */
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x = (x & 0xffff) + (x >> 16);
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/* add up carry.. */
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x = (x & 0xffff) + (x >> 16);
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return x;
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}
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static unsigned int do_csum(const unsigned char *buff, int len)
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{
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int odd;
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unsigned int result = 0;
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if (len <= 0)
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goto out;
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odd = 1 & (unsigned long) buff;
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if (odd) {
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#ifdef __LITTLE_ENDIAN
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result += (*buff << 8);
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#else
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result = *buff;
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#endif
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len--;
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buff++;
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}
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if (len >= 2) {
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if (2 & (unsigned long) buff) {
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result += *(unsigned short *) buff;
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len -= 2;
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buff += 2;
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}
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if (len >= 4) {
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const unsigned char *end = buff + ((unsigned)len & ~3);
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unsigned int carry = 0;
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do {
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unsigned int w = *(unsigned int *) buff;
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buff += 4;
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result += carry;
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result += w;
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carry = (w > result);
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} while (buff < end);
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result += carry;
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result = (result & 0xffff) + (result >> 16);
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}
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if (len & 2) {
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result += *(unsigned short *) buff;
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buff += 2;
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}
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}
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if (len & 1)
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#ifdef __LITTLE_ENDIAN
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result += *buff;
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#else
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result += (*buff << 8);
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#endif
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result = from32to16(result);
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if (odd)
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result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
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out:
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return result;
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}
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__wsum csum_partial(const void *buff, int len, __wsum wsum)
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{
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unsigned int sum = (__force unsigned int)wsum;
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unsigned int result = do_csum(buff, len);
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/* add in old sum, and carry.. */
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result += sum;
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if (sum > result)
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result += 1;
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return (__force __wsum)result;
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}
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inline __u32 reiserfs_xattr_hash(const char *msg, int len)
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{
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return csum_partial(msg, len, 0);
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}
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int reiserfs_check_xattr(const void *body, int len)
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{
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const struct reiserfs_xattr_header *xah = body;
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int hdrsz = sizeof(struct reiserfs_xattr_header);
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__u32 hash;
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if (len < hdrsz)
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return -EINVAL;
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hash = reiserfs_xattr_hash(body + hdrsz, len - hdrsz);
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return xah->h_magic == cpu_to_le32(REISERFS_XATTR_MAGIC) &&
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le32_to_cpu(xah->h_hash) == hash;
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}
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int reiserfs_acl_count(size_t size)
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{
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ssize_t s;
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size -= sizeof(struct reiserfs_acl_header);
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s = size - 4 * sizeof(struct reiserfs_acl_entry_short);
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if (s < 0) {
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if (size % sizeof(struct reiserfs_acl_entry_short))
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return -1;
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return size / sizeof(struct reiserfs_acl_entry_short);
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} else {
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if (s % sizeof(struct reiserfs_acl_entry))
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return -1;
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return s / sizeof(struct reiserfs_acl_entry) + 4;
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}
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}
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