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Code Issues Releases Activity

Do not read away the target directory entry when encountering deleted

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files after a seekdir().

The seekdir shall set the position for the next readdir operation.
When the _readdir_unlocked() encounters deleted entry, dd_loc is
already advanced. Continuing the loop leads to premature read of
the target entry.

Submitted by:	Marc Balmer <mbalmer at openbsd org>
Obtained from:	OpenBSD
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2008-05-05 14:05:23 +00:00
parent f2db8876a0
commit 90c68c1799
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=178772
3 changed files with 9 additions and 8 deletions
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13
lib/libc/gen/readdir.c
View File

@ -48,8 +48,9 @@ __FBSDID("$FreeBSD$");
* get next entry in a directory.
*/
struct dirent *
_readdir_unlocked(dirp)
_readdir_unlocked(dirp, skip)
DIR *dirp;
int skip;
{
struct dirent *dp;
@ -72,7 +73,7 @@ _readdir_unlocked(dirp)
dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
return (NULL);
dirp->dd_loc += dp->d_reclen;
if (dp->d_ino == 0)
if (dp->d_ino == 0 && skip)
continue;
if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
continue;
@ -88,11 +89,11 @@ readdir(dirp)
if (__isthreaded) {
_pthread_mutex_lock(&dirp->dd_lock);
dp = _readdir_unlocked(dirp);
dp = _readdir_unlocked(dirp, 1);
_pthread_mutex_unlock(&dirp->dd_lock);
}
else
dp = _readdir_unlocked(dirp);
dp = _readdir_unlocked(dirp, 1);
return (dp);
}
@ -109,11 +110,11 @@ readdir_r(dirp, entry, result)
errno = 0;
if (__isthreaded) {
_pthread_mutex_lock(&dirp->dd_lock);
if ((dp = _readdir_unlocked(dirp)) != NULL)
if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
_pthread_mutex_unlock(&dirp->dd_lock);
}
else if ((dp = _readdir_unlocked(dirp)) != NULL)
else if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
if (errno != 0) {

2
lib/libc/gen/telldir.c
View File

@ -98,7 +98,7 @@ _seekdir(dirp, loc)
dirp->dd_seek = lp->loc_seek;
dirp->dd_loc = 0;
while (dirp->dd_loc < lp->loc_loc) {
dp = _readdir_unlocked(dirp);
dp = _readdir_unlocked(dirp, 0);
if (dp == NULL)
break;
}

2
lib/libc/gen/telldir.h
View File

@ -59,7 +59,7 @@ struct _telldir {
long td_loccnt; /* index of entry for sequential readdir's */
};
struct dirent *_readdir_unlocked(DIR *);
struct dirent *_readdir_unlocked(DIR *, int);
void _reclaim_telldir(DIR *);
void _seekdir(DIR *, long);