diff options
| author | Ben Pfaff <blp@nicira.com> | 2012-07-26 14:42:58 -0700 |
|---|---|---|
| committer | Ben Pfaff <blp@nicira.com> | 2012-08-01 10:05:34 -0700 |
| commit | 01ca539f5c89fab1ea9a355d4cb75383dfb25da5 (patch) | |
| tree | 57884161802e8a7fb3ef9a2e7bb2dc73813e5bd6 /ovsdb | |
| parent | 77c513a44ab85264aed7c38387ef221ad30e461c (diff) | |
ovsdb: Make "ovsdb-tool create" work through a dangling symlink.
open() with O_CREAT|O_EXCL yields EEXIST if the name passed in is a
symlink, but we would like "ovsdb-tool create /etc/openvswitch/conf.db" to
work if /etc/openvswitch/conf.db is a symlink to elsewhere in the file
system. This commit fixes the problem. It introduces a theoretical race,
but no one should be doing "ovsdb-tool create" in parallel anyhow; O_EXCL
is just an idiot check here, not required to be fail-safe.
Debian bug #681880.
CC: 681880@bugs.debian.org
Reported-by: Bastian Blank <waldi@debian.org>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'ovsdb')
| -rw-r--r-- | ovsdb/log.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/ovsdb/log.c b/ovsdb/log.c index ab4a150c..9b882dc4 100644 --- a/ovsdb/log.c +++ b/ovsdb/log.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2009, 2010, 2011 Nicira, Inc. +/* Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -95,7 +95,16 @@ ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode, } else if (open_mode == OVSDB_LOG_READ_WRITE) { flags = O_RDWR; } else if (open_mode == OVSDB_LOG_CREATE) { - flags = O_RDWR | O_CREAT | O_EXCL; + if (stat(name, &s) == -1 && errno == ENOENT + && lstat(name, &s) == 0 && S_ISLNK(s.st_mode)) { + /* 'name' is a dangling symlink. We want to create the file that + * the symlink points to, but POSIX says that open() with O_EXCL + * must fail with EEXIST if the named file is a symlink. So, we + * have to leave off O_EXCL and accept the race. */ + flags = O_RDWR | O_CREAT; + } else { + flags = O_RDWR | O_CREAT | O_EXCL; + } } else { NOT_REACHED(); } |