From cabf1ab5da244a22f50146e3ebe638c11ce55b7e Mon Sep 17 00:00:00 2001 From: jhb Date: Thu, 14 Aug 2014 20:20:21 +0000 Subject: MFC 268531,269079,269204: Fix various edge cases with rewinddir(), seekdir(), and telldir(): - In the unionfs case, opendir() and fdopendir() read the directory's full contents and cache it. This cache is not refreshed when rewinddir() is called, so rewinddir() will not notice updates to a directory. Fix this by splitting the code to fetch a directory's contents out of __opendir_common() into a new _filldir() function and call this from rewinddir() when operating on a unionfs directory. - If rewinddir() is called on a directory opened with fdopendir() before any directory entries are fetched, rewinddir() will not adjust the seek location of the backing file descriptor. If the file descriptor passed to fdopendir() had a non-zero offset, the rewinddir() will not rewind to the beginning. Fix this by always seeking back to 0 in rewinddir(). This means the dd_rewind hack can also be removed. - Add missing locking to rewinddir() - POSIX says that passing a location returned by telldir() to seekdir() after an intervening call to rewinddir() is undefined, so reclaim any pending telldir() cookies in the directory when rewinddir() is called. - If telldir() is called immediately after a call to seekdir(), POSIX requires the return value of telldir() to equal the value passed to seekdir(). The current seekdir code with SINGLEUSE enabled breaks this case as each call to telldir() allocates a new cookie. Instead, remove the SINGLEUSE code and change telldir() to look for an existing cookie for the directory's current location rather than always creating a new cookie. PR: 121656 --- lib/libc/gen/readdir.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'lib/libc/gen/readdir.c') diff --git a/lib/libc/gen/readdir.c b/lib/libc/gen/readdir.c index 324870b..69f59d1 100644 --- a/lib/libc/gen/readdir.c +++ b/lib/libc/gen/readdir.c @@ -61,12 +61,14 @@ _readdir_unlocked(dirp, skip) return (NULL); dirp->dd_loc = 0; } - if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) { + if (dirp->dd_loc == 0 && + !(dirp->dd_flags & (__DTF_READALL | __DTF_SKIPREAD))) { dirp->dd_size = _getdirentries(dirp->dd_fd, dirp->dd_buf, dirp->dd_len, &dirp->dd_seek); if (dirp->dd_size <= 0) return (NULL); } + dirp->dd_flags &= ~__DTF_SKIPREAD; dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc); if ((long)dp & 03L) /* bogus pointer check */ return (NULL); -- cgit v1.1