Dailydave mailing list archives
Re: checkpointing page
From: Eduardo Tongson <propolice () gmail com>
Date: Tue, 28 Jun 2005 16:53:44 +0000
http://www.geocities.com/asimshankar/checkpointing/
fwiw DragonFlyBSD <dragonflybsd.org> has checkpointing in its base with similar caveats as the above implementation. a snip from sys_checkpoint(2) """ CHECKPOINT FEATURES The system checkpointing code will save the process register state (including floating point registers), signal state, file descriptors rep- resenting regular files or directories (anything that can be converted into a file handle for storage), and both shared and private memory map- pings. Private, writable mappings are copied to the checkpoint file while shared mappings and stored by referencing the file handle and off- set. Note that the system checkpointing code does not retain references to deleted files, so mappings and open descriptors of deleted files can- not be restored. Unpredictable operation will occur if a checkpoint- unaware program is restored and some of the underlying files mapped by the program have changed. The system checkpointing code is not able to retain the process pid, process group, user/group creds, or descriptors 0, 1, and 2. These will be inherited from whomever restores the checkpoint. When a checkpointed program is restored modified private mappings will be mapped from the checkpoint file itself, but major portions of the origi- nal program binary will be mapped from the original program binary. If the resumed program is checkpointed again the system will automatically copy any mappings from the original checkpoint file to the new one, since the original is likely being replaced. The caller must not truncate the existing checkpoint file when creating a new one or specify the existing file's file descriptor as the new one as this will destroy the data that the checkpoint operation needs to copy to the new file. """ -- Eduardo Tongson _______________________________________________ Dailydave mailing list Dailydave () lists immunitysec com https://lists.immunitysec.com/mailman/listinfo/dailydave
Current thread:
- checkpointing page Dave Aitel (Jun 28)
- Re: checkpointing page Eduardo Tongson (Jun 28)