View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000489 | 1003.1(2008)/Issue 7 | System Interfaces | public | 2011-09-01 15:48 | 2019-06-10 08:55 |
| Reporter | eblake | Assigned To | ajosey | ||
| Priority | normal | Severity | Objection | Type | Error |
| Status | Closed | Resolution | Accepted | ||
| Name | Eric Blake | ||||
| Organization | Red Hat | ||||
| User Reference | ebb.truncate | ||||
| Section | truncate | ||||
| Page Number | 2136 | ||||
| Line Number | 67570 | ||||
| Interp Status | --- | ||||
| Final Accepted Text | |||||
| Summary | 0000489: truncate should affect timestamps even for no size change | ||||
| Description | The wording for ftruncate() requires mtime and ctime updates on successful completion, even when no change in file size occurs. However, truncate() does not describe what happens when no size change occurs, which is inconsistent with ftruncate(), and which is at odds with XBD 4.8 stating that ctime updates occur even if the metadata written (in this case, the file size) is identical to what it already was. | ||||
| Desired Action | At line 67570 [XSH truncate() DESCRIPTION], change the sentence: "Upon successful completion, if the file size is changed, truncate( ) shall mark for update the last data modification and last file status change timestamps of the file, and the S_ISUID and S_ISGID bits of the file mode may be cleared." to: "Upon successful completion, truncate( ) shall mark for update the last data modification and last file status change timestamps of the file, and the S_ISUID and S_ISGID bits of the file mode may be cleared." | ||||
| Tags | tc2-2008 | ||||
|
|
While I agree with Eric about the strange inconsistency between truncate() and ftruncate(), the approved change *will* make Linux nonconformant. On Linux, the ftruncate() system call always changes the file timestamps, even if the file size is not changed. However, Linux truncate() only changes the timestamps if the file size changes. (This observation is based on my reading of the kernel source and some userspace programs to test these details.) I haven't delved into the history, but quite possibly the Linux behavior occurs because the implementers looked closely at the specifications for these two functions. I think some consideration should be given to existing Linux behavior before modifying the standard in a way that renders Linux nonconformant. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2011-09-01 15:48 | eblake | New Issue | |
| 2011-09-01 15:48 | eblake | Status | New => Under Review |
| 2011-09-01 15:48 | eblake | Assigned To | => ajosey |
| 2011-09-01 15:48 | eblake | Name | => Eric Blake |
| 2011-09-01 15:48 | eblake | Organization | => Red Hat |
| 2011-09-01 15:48 | eblake | User Reference | => ebb.truncate |
| 2011-09-01 15:48 | eblake | Section | => truncate |
| 2011-09-01 15:48 | eblake | Page Number | => 2136 |
| 2011-09-01 15:48 | eblake | Line Number | => 67570 |
| 2011-09-01 15:48 | eblake | Interp Status | => --- |
| 2011-09-01 15:50 | eblake | Relationship added | related to 0000485 |
| 2011-09-08 15:32 | nick | Status | Under Review => Resolved |
| 2011-09-08 15:32 | nick | Resolution | Open => Accepted |
| 2011-09-08 15:32 | nick | Tag Attached: tc2-2008 | |
| 2012-02-14 10:36 | mkerrisk | Note Added: 0001127 | |
| 2019-06-10 08:55 | agadmin | Status | Resolved => Closed |
