| commit | 238903ea53fe33a5d1d6f5f81d2fd00c33c1140b | |
| author | Ben Kibbey <bjk@luxsci.net> | |
| Tue, 4 Aug 2015 02:30:06 +0000 (3 22:30 -0400) | ||
| committer | Ben Kibbey <bjk@luxsci.net> | |
| Sat, 8 Aug 2015 14:11:26 +0000 (8 10:11 -0400) | ||
| tree | 702bd8ffee22132d7d64f1b84b7036b0cfab50eb | treesnapshot (tar.gz zip) |
| parent | 6d7f0666060ba88aadad4f3584c6450a1b0118f4 | commitdiff |
Add advisory file locking.
These advisory locks are not enforced by the kernel. This means another
non-pwmd process may do with the data file what it wants. It is mainly
for use with multiple instances of pwmd that share a common
"data_directory". The SAVE and PASSWD commands are the only commands
that do an exclusive (write) lock for their duration. The OPEN and
KEYGRIP commands keeps a shared (read-only) lock for its duration. All
other commands do a shared lock upon startup when checking the checksum
of the data file; then the lock is released.
There is the problem that these advisory locks, obtained via flock(),
aren't POSIX. Noteably, they aren't implemented on at least Solaris.
These advisory locks are not enforced by the kernel. This means another
non-pwmd process may do with the data file what it wants. It is mainly
for use with multiple instances of pwmd that share a common
"data_directory". The SAVE and PASSWD commands are the only commands
that do an exclusive (write) lock for their duration. The OPEN and
KEYGRIP commands keeps a shared (read-only) lock for its duration. All
other commands do a shared lock upon startup when checking the checksum
of the data file; then the lock is released.
There is the problem that these advisory locks, obtained via flock(),
aren't POSIX. Noteably, they aren't implemented on at least Solaris.