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| author | Al Viro <viro@zeniv.linux.org.uk> | 2010-06-06 23:49:18 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-08-09 16:48:15 -0400 |
| commit | f8ad850f11e11d10e7de1a16ca53cb193afc9313 (patch) | |
| tree | 4812193c6be29f41d3de3ae74705e95a9566546c /fs/hostfs/hostfs.h | |
| parent | f8d7e1877e5121841bc9a4d284a04dbc13f45bea (diff) | |
| download | lwn-f8ad850f11e11d10e7de1a16ca53cb193afc9313.tar.gz lwn-f8ad850f11e11d10e7de1a16ca53cb193afc9313.zip | |
try to get rid of races in hostfs open()
In case of mode mismatch, do *not* blindly close the descriptor
another openers might be using right now. Open the underlying
file with currently sufficient mode, then
* if current mode has grown so that it's sufficient for
us now, just close our new fd
* if current mode has grown and our fd is *not* enough
to cover it, close and repeat.
* otherwise, install our fd if the file hadn't been
opened at all or dup2() our fd over the current one (and close
our fd).
Critical section is protected by mutex; yes, system-wide. All
we do under it is a bunch of comparison and maybe an overwriting
dup2() on host.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/hostfs/hostfs.h')
| -rw-r--r-- | fs/hostfs/hostfs.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h index ea87e224ed97..6bbd75c5589b 100644 --- a/fs/hostfs/hostfs.h +++ b/fs/hostfs/hostfs.h @@ -74,6 +74,7 @@ extern void *open_dir(char *path, int *err_out); extern char *read_dir(void *stream, unsigned long long *pos, unsigned long long *ino_out, int *len_out); extern void close_file(void *stream); +extern int replace_file(int oldfd, int fd); extern void close_dir(void *stream); extern int read_file(int fd, unsigned long long *offset, char *buf, int len); extern int write_file(int fd, unsigned long long *offset, const char *buf, |