View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000943 | 1003.1(2013)/Issue7+TC1 | System Interfaces | public | 2015-05-01 08:14 | 2019-06-10 08:54 |
| Reporter | EdSchouten | Assigned To | ajosey | ||
| Priority | normal | Severity | Comment | Type | Omission |
| Status | Closed | Resolution | Accepted As Marked | ||
| Name | Ed Schouten | ||||
| Organization | Nuxi | ||||
| User Reference | |||||
| Section | open() and openat() | ||||
| Page Number | 1395 | ||||
| Line Number | 46152 | ||||
| Interp Status | Approved | ||||
| Final Accepted Text | See 0000943:0002710. | ||||
| Summary | 0000943: open() and openat() fail to describe what happens when opening a socket | ||||
| Description | When I take a look at various operating systems, I observe the following: NetBSD: $ ls -l /var/run/log srw-rw-rw- 1 root wheel 0 May 1 10:01 /var/run/log $ cat /var/run/log cat: /var/run/log: Operation not supported FreeBSD: $ ls -l /var/run/log srw-rw-rw- 1 root wheel 0 Mar 15 15:32 /var/run/log= $ cat /var/run/log cat: /var/run/log: Protocol wrong type for socket Linux: $ ls -l /var/run/acpid.socket srw-rw-rw- 1 root root 0 mei 1 09:58 /var/run/acpid.socket= $ cat /var/run/acpid.socket cat: /var/run/acpid.socket: No such device or address Three different systems, three different error codes. If I look at the description of open() and openat(), it seems that there's also no error code reserved for this situation. | ||||
| Desired Action | Pick a relevant error code and have it documented, so that operating systems can come up with a uniform way of dealing with this condition. | ||||
| Tags | tc2-2008 | ||||
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It could be argued that the standard already requires EOPNOTSUPP for this, as XSH 2.3 describes this error as "Operation not supported on socket" and says in the introductory paragraphs "Implementations shall not generate a different error number from one required by this volume of POSIX.1-2008 for an error condition described in this volume of POSIX.1-2008". In this case, it would be just an editorial oversight that EOPNOTSUPP is not listed for open(). Solaris and HP-UX both give EOPNOTSUPP (which I assume is what the reported NetBSD error text corresponds to). |
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FreeBSD's [EPROTOTYPE] error is caused by an extension in cat, where catting a socket causes cat to connect to it (as a stream socket) and receives from it until the connection is closed. Trying to open a socket using open() fails with [EOPNOTSUPP] as in NetBSD. |
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How do you get EOPNOTSUPP? It is in the man page... If you create a socket with mknod(), Solaris allows to open this socket and returns EIO for a read() attempt. EOPNOTSUPP seems to be the open() error for (still) actice sockets that have been created in the filesystem namespace using a socket() call. |
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If there is a way to create a socket in the file system for which open() succeeds, then we should add EOPNOTSUPP as a "may fail" error instead of "shall fail". However, I tried creating a socket using mknod() on Solaris 11.1 and got EOPNOTSUPP when trying to open it: # truss ./a.out 2>&1 | grep mknod mknod("/tmp/mysock2", 0140600, 0x00000000) = 0 # ls -l /tmp/mysock2 srw------- 1 root root 0 May 6 16:22 /tmp/mysock2 # truss cat /tmp/mysock2 2>&1 | grep mysock open64("/tmp/mysock2", O_RDONLY) Err#122 EOPNOTSUPP |
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Then the result seems to depend on the filesystem type. The open() call fails for "tmpfs" and "ufs" (did not yet test ZFS), but it succeeds on "lofs" as my first test has been made on /home/uname/* My previous assumption about the status (active or not) seems to be wrong. |
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Interpretation response ------------------------ The standard clearly states that errno must be set to EOPNOTSUPP if an attempt is made to perform an operation on a socket that is not supported, and conforming implementations must conform to this. Rationale: ------------- The standard requires EOPNOTSUPP if open() fails to open a socket, as XSH 2.3 describes this error as "Operation not supported on socket" and says in the introductory paragraphs "Implementations shall not generate a different error number from one required by this volume of POSIX.1-2008 for an error condition described in this volume of POSIX.1-2008". Notes to the Editor (not part of this interpretation): ------------------------------------------------------- On page 1395 line 46152 insert before [ETXTBSY]:
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Interpretation Proposed: June 19 2015 |
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Interpretation approved: 7 Sep 2015 |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2015-05-01 08:14 | EdSchouten | New Issue | |
| 2015-05-01 08:14 | EdSchouten | Status | New => Under Review |
| 2015-05-01 08:14 | EdSchouten | Assigned To | => ajosey |
| 2015-05-01 08:14 | EdSchouten | Name | => Ed Schouten |
| 2015-05-01 08:14 | EdSchouten | Organization | => Nuxi |
| 2015-05-01 08:14 | EdSchouten | Section | => open() and openat() |
| 2015-05-01 08:14 | EdSchouten | Page Number | => unknown |
| 2015-05-01 08:14 | EdSchouten | Line Number | => unknown |
| 2015-05-01 08:38 | geoffclare | Note Added: 0002645 | |
| 2015-05-01 15:36 | jilles | Note Added: 0002646 | |
| 2015-05-06 14:13 | joerg | Note Added: 0002653 | |
| 2015-05-06 15:27 | geoffclare | Note Added: 0002655 | |
| 2015-05-06 15:34 | joerg | Note Added: 0002656 | |
| 2015-05-06 15:36 | joerg | Note Edited: 0002656 | |
| 2015-05-06 15:36 | joerg | Note Edited: 0002656 | |
| 2015-06-11 16:34 | geoffclare | Project | 1003.1(2008)/Issue 7 => 1003.1(2013)/Issue7+TC1 |
| 2015-06-11 16:39 | Don Cragun | Note Added: 0002710 | |
| 2015-06-11 16:42 | Don Cragun | Page Number | unknown => 1395 |
| 2015-06-11 16:42 | Don Cragun | Line Number | unknown => 46152 |
| 2015-06-11 16:42 | Don Cragun | Interp Status | => Pending |
| 2015-06-11 16:42 | Don Cragun | Final Accepted Text | => See 0000943:0002710. |
| 2015-06-11 16:42 | Don Cragun | Status | Under Review => Interpretation Required |
| 2015-06-11 16:42 | Don Cragun | Resolution | Open => Accepted As Marked |
| 2015-06-11 16:42 | Don Cragun | Tag Attached: tc2-2008 | |
| 2015-06-19 07:07 | ajosey | Interp Status | Pending => Proposed |
| 2015-06-19 07:07 | ajosey | Note Added: 0002724 | |
| 2015-09-07 11:33 | ajosey | Interp Status | Proposed => Approved |
| 2015-09-07 11:33 | ajosey | Note Added: 0002820 | |
| 2019-06-10 08:54 | agadmin | Status | Interpretation Required => Closed |
