[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:44 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated ==
[1003.1(2013)/Issue7+TC1 0001044]: Calling setsid as part of posix_spawn
The following issue has been set as RELATED TO issue 0001208. == http://austingroupbugs.net/view.php?id=1044 == Reported By:daurnimator Assigned To: == Project:1003.1(2013)/Issue7+TC1 Issue ID: 1044 Category: System Interfaces Type: Enhancement Request Severity: Editorial Priority: normal Status: Resolved Name: Daurnimator Organization: User Reference: Section:posix_spawn Page Number:0 Line Number:0 Interp Status: --- Final Accepted Text:http://austingroupbugs.net/view.php?id=1044#c3650 Resolution: Accepted As Marked Fixed in Version: == Date Submitted: 2016-04-14 01:07 UTC Last Modified: 2017-04-07 12:23 UTC == Summary:Calling setsid as part of posix_spawn == Relationships ID Summary -- related to 0001208 calling chdir as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2016-04-14 01:07 daurnimatorNew Issue 2016-04-14 01:07 daurnimatorName => Daurnimator 2016-04-14 01:07 daurnimatorSection => posix_spawn 2016-04-14 01:07 daurnimatorPage Number => 0 2016-04-14 01:07 daurnimatorLine Number => 0 2016-04-14 01:43 daurnimatorIssue Monitored: daurnimator 2016-08-19 08:26 Florian Weimer Issue Monitored: Florian Weimer 2017-03-23 17:06 geoffclare Note Added: 0003650 2017-03-23 17:09 geoffclare Note Edited: 0003650 2017-03-30 15:13 geoffclare Interp Status => --- 2017-03-30 15:13 geoffclare Final Accepted Text => http://austingroupbugs.net/view.php?id=1044#c3650 2017-03-30 15:13 geoffclare Status New => Resolved 2017-03-30 15:13 geoffclare Resolution Open => Accepted As Marked 2017-03-30 15:13 geoffclare Tag Attached: issue8 2017-04-05 02:50 daurnimatorNote Added: 0003658 2017-04-07 10:52 geoffclare Note Edited: 0003650 2017-04-07 10:54 geoffclare Note Added: 0003665 2017-04-07 12:23 daurnimatorNote Added: 0003666 2018-09-07 18:39 eblake Relationship added related to 0001208 ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:46 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been set as RELATED TO issue 0001044. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:39 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been SUBMITTED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:39 UTC == Summary:calling chdir as part of posix_spawn Description: One notable missing feature from posix_spawn is the ability to change the initial working directory of the new process. Of course, in the common case, it is possible to exec a shim process that will change the directory (GNU coreutils has 'env -C dir program ...' that will do this, but the standard itself does not have such a shim program, so users have to come up with their own). But even more complex is the fact that posix_spawn can change access permissions with PSOIX_SPAWN_RESETIDS, such that the parent may have permission to change to a particular directory, but the child with a different id cannot do so. There is also the case that a multi-threaded parent process can use openat() to open files relative to a particular directory without changing the global state of the current working directory, but there is no interface for openat() within posix_spawn (and it may be prohibitively expensive to convert a relative name into an absolute one). Thus, it can be argued that changing the directory needs to be directly part of posix_spawn(). Solaris has implemented an extension for chdir with a _np suffix (non-portable), and documents that relative names for posix_spawn(,path) and posix_spawnp(,file) are interpreted to the working directory selected for the child: https://docs.oracle.com/cd/E86824_01/html/E54766/posix-spawn-file-actions-addchdir-np-3c.html I'm proposing that we standardize this, but drop the _np suffix (since by standardizing it, it will no longer be non-portable), and also add a counterpart for fchdir. The addition of fchdir makes it possible to simulate openat semantics without actually needing to add posix_spawn_file_actions_addopenat. Note that I did not standardize the notion of a chroot file action (in part due to no existing practice), although such an extension may still make sense. Fix a couple of issues in posix_spawn_file_addclose while at it: you can't delete open/close actions from an existing file_actions object, only add more; and ENOMEM should be a 'shall fail' rather than 'may fail' error to match posix_spawn_file_adddup2. Yes, the additions to the XRAT example are just as borked as the existing implementation for handling an addopen action at lines 126723-126763 and 126852-126860 (very easy to write beyond end of fixed-length array, parse failure on filename containing '*', failure to fail with EBADF for negative filedes, etc) - but being consistently bad in something that is mainly for demo purposes isn't the end of the world. The use of _exit() instead of exit() in the example matches the resolution for http://austingroupbugs.net/view.php?id=1044. Desired Action: Proposed changes (2017 edition page and line numbers): On page 341 line 11588 (XBD ), insertint posix_spawn_file_actions_addchdir(posix_spawn_file_actions_t *restrict, const char *restrict); On page 341 line 11592 (), insertint posix_spawn_file_actions_addfchdir(posix_spawn_file_actions_t *, int); On page 1453 line 48227 (XSH posix_spawn DESCRIPTION), change:a pathname that identifies the new process image file to execute.to:a pathname that identifies the new process image file to execute; if the pathname does not start with a it shall be interpreted relative to the working directory of the child process after all file_actions have been performed. On page 1453 line 48229, change:the file parameter shall be used as the pathname for the new process image file.to:the file parameter shall be used as the pathname for the new process image file; if this pathname does not start with a it shall be interpreted relative to the working directory of the child process after all file_actions have been performed. On page 1453 line 48239, add a
Re: Status of pipefail for standardization
Date:Fri, 7 Sep 2018 09:35:39 +0100 From:Geoff Clare Message-ID: <20180907083539.GA5774@lt2.masqnet> | Since kre reported in bugnote 4102 that he added pipefail to the | NetBSD sh and it does not support arrays, it seems we have our | answer on that one. I am not sure that what we do necessarily provides proof for anything, but yes, pipefail is useful without being able to see the status of the individual processes (which is what the "support arrays" side issue is really all about.).It might be even more useful with that extra, but sometimes simply knowing "did the entire pipe work, or did anything fail?" is all that is needed - and my current impression is that in many cases, that is exactly what is needed. Before going on to the "what if" part of this message, I would also say that in the NetBSD man page description of pipefail we handle the exit status issue (with/without pipefail, with/without !) a little differently. Our text defines a pipestatus for a pipeline, which is the thing that pipefail controls, and then derives the exit status of a pipeline from the pipestatus of that pipeline based upon the presence, or not, of the ! word. The effect is the same as the big table, but it is rather more concise. For when more than success/fail is needed, I still don't believe that arrays are needed, the status information for a list of commands is just a list of integers, and can easily be handled as a list using traditional shell strings. (This is not a case where random unknown data needs to be handled, a space seeparated ordered list of numbers would be just fine.) And while in note 3905 Stephane provided a link to a web page showing how the status information can be extracted now (with no additional mechanism at all - not even pipefail) I kind of suspect that's rather more complex than most people would want, and too susceptible to minor errors (accidentally leave a \ out from ahead of one of the | and it fails in not so obvious ways). So, what would be needed, not to have pipefail, but to allow the status to be extracted (pipefail enabled or not) would be some new mechanism to provide the info (of which an array, or just a variable, with a magic name is certtainly a possibility.) I am not sure what the attitude is here to creating new special parameters, the ones we have all seem to have originated in the original Bourne shell, and no-one has ever added anything new (I actually had $+ for a short while - never released anywhere - which was a comlpement to $- and contained the single letter options that were not set ... more for symmetry than to solve any real problem ... so it went away again). But if anything cries out for a new special parameter it would be this - to make the exit status of the processes that form a pipeline available. If I had to pick something, I'd use $| and define it to be the a space separated list of exit status values ($?) for the commands that form a pipeline. It would be set (and have a lifetime) exactly the same as applies to $? - and in the case of a degenerate pipeline (a pipeline with no pipe operators, ie: a simple command), $| and $? would be identical (as they would be before any command had run.) I have not implemented that, as there has been no demand, so I cannot state that it will work (it is obviously implementable, just as it is obviously possible to implement the array method, for shells willing to add all the mechanism necessary to support arrays as a general concept) - and so it is way too early to even consider standardising anything in this area - this is just so I can get a general "sense of the room" as to whether this would be an acceptable solution, or simply considered out of the question. kre
Re: Status of pipefail for standardization
Drew DeVault wrote, on 05 Sep 2018: > > On 2018-09-05 8:18 AM, Drew DeVault wrote: > > Copying David on the thread. David, do you have some time to look over > > this proposal for the POSIX shell? > > My email to David bounced and I don't have a better address for him. > Does anyone else have a way of getting in touch? As discussed in yesterday's call, it seems unlikely that we will get any input from David. So the options are to try and get input from someone else who works on ksh93 (e.g. Glenn Fowler?) or just to proceed with what we have already. I think the main question we were hoping for input on is whether it is worth standardising pipefail without support for arrays. Since kre reported in bugnote 4102 that he added pipefail to the NetBSD sh and it does not support arrays, it seems we have our answer on that one. -- Geoff Clare The Open Group, Apex Plaza, Forbury Road, Reading, RG1 1AX, England
[1003.1(2016)/Issue7+TC2 0001130]: Address 0 does not make sense for the c command
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1130 == Reported By:Antonio Diaz Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1130 Category: Shell and Utilities Type: Error Severity: Objection Priority: normal Status: Resolved Name: Antonio Diaz Organization: GNU User Reference: Section:ed Page Number:2682 Line Number:87448-87449 Interp Status: --- Final Accepted Text:See http://austingroupbugs.net/view.php?id=1130#c4105 Resolution: Accepted As Marked Fixed in Version: == Date Submitted: 2017-03-21 17:07 UTC Last Modified: 2018-09-07 08:17 UTC == Summary:Address 0 does not make sense for the c command == Relationships ID Summary -- related to 0001131 The synopsis of the i command is wrong ... == Issue History Date ModifiedUsername FieldChange == 2017-03-21 17:07 Antonio Diaz New Issue 2017-03-21 17:07 Antonio Diaz Name => Antonio Diaz 2017-03-21 17:07 Antonio Diaz Organization => GNU 2017-03-21 17:07 Antonio Diaz Section => ed 2017-03-21 17:07 Antonio Diaz Page Number => 0 2017-03-21 17:07 Antonio Diaz Line Number => 0 2017-03-21 17:10 Antonio Diaz Issue Monitored: Antonio Diaz 2017-03-21 18:26 salty-horseIssue Monitored: salty-horse 2018-08-30 16:24 nick Page Number 0 => 2682 2018-08-30 16:24 nick Line Number 0 => 87448-87449 2018-08-30 16:24 nick Interp Status => --- 2018-08-31 14:16 geoffclare Note Added: 0004098 2018-09-06 16:33 geoffclare Relationship added related to 0001131 2018-09-06 16:36 nick Note Added: 0004105 2018-09-06 16:37 nick Final Accepted Text => See Bugnote:0004105 2018-09-06 16:37 nick Status New => Resolution Proposed 2018-09-06 16:37 nick Resolution Open => Accepted As Marked 2018-09-06 16:37 nick Tag Attached: tc3-2008 2018-09-06 16:38 nick Status Resolution Proposed => Resolved 2018-09-06 16:43 nick Note Added: 0004107 2018-09-06 16:43 nick Note Edited: 0004107 2018-09-07 08:17 geoffclare Final Accepted Text See Bugnote:0004105 => See http://austingroupbugs.net/view.php?id=1130#c4105 ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 19:29 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated 2018-09-07 18:55 eblake Tag Attached: issue8 2018-09-07 19:02 eblake Note Added: 0004109 2018-09-07 19:04 eblake Desired Action Updated 2018-09-07 19:29 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 19:02 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == -- (0004109) eblake (manager) - 2018-09-07 19:02 http://austingroupbugs.net/view.php?id=1208#c4109 -- Perhaps the two cleanups in posix_spawn_file_actions_addclose (deleting a spurious "or delete", and turning ENOMEM into shall fail instead of may fail) should be split into a separate bug targeted at TC3. Also, such a separate bug could add even more disclaimers into the XRAT example code about how insecure it is, and that it exists merely as a starting point rather than a robust implementation. Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated 2018-09-07 18:55 eblake Tag Attached: issue8 2018-09-07 19:02 eblake Note Added: 0004109 ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 19:35 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated 2018-09-07 18:55 eblake Tag Attached: issue8 2018-09-07 19:02 eblake Note Added: 0004109 2018-09-07 19:04 eblake Desired Action Updated 2018-09-07 19:29 eblake Desired Action Updated 2018-09-07 19:35 eblake Description Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:49 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:55 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:51 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 18:53 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
The following issue has been UPDATED. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 19:04 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated 2018-09-07 18:55 eblake Tag Attached: issue8 2018-09-07 19:02 eblake Note Added: 0004109 2018-09-07 19:04 eblake Desired Action Updated ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 22:18 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == -- (0004110) eblake (manager) - 2018-09-07 22:18 http://austingroupbugs.net/view.php?id=1208#c4110 -- As a side note: Windows CreateProcess() already supports changing directories at the time of spawning a child. While you wouldn't typically see posix_spawn() and CreateProcess() mixed in the same program, it is nice to know that the concept of changing directory for the child process is already common in an existing OS. Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated 2018-09-07 18:55 eblake Tag Attached: issue8 2018-09-07 19:02 eblake Note Added: 0004109 2018-09-07 19:04 eblake Desired Action Updated 2018-09-07 19:29 eblake Desired Action Updated 2018-09-07 19:35 eblake Description Updated 2018-09-07 22:18 eblake Note Added: 0004110 ==
[1003.1(2016)/Issue7+TC2 0001208]: calling chdir as part of posix_spawn
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1208 == Reported By:eblake Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1208 Category: System Interfaces Type: Enhancement Request Severity: Objection Priority: normal Status: New Name: Eric Blake Organization: Red Hat User Reference: posix_spawn.chdir Section:posix_spawn Page Number:1452 ff. Line Number:48227 ff. Interp Status: --- Final Accepted Text: == Date Submitted: 2018-09-07 18:39 UTC Last Modified: 2018-09-07 22:44 UTC == Summary:calling chdir as part of posix_spawn == Relationships ID Summary -- related to 0001044 Calling setsid as part of posix_spawn == -- (0004111) eblake (manager) - 2018-09-07 22:44 http://austingroupbugs.net/view.php?id=1208#c4111 -- In fact, we could get by with JUST posix_spawn_file_actions_addfchdir(posix_spawn_file_actions_t*, int), since: posix_spawn_file_actions_addchdir(, "foo"); can be rewritten as: posix_spawn_file_actions_addopen(, 5, "foo", O_RDONLY|O_DIRECTORY|O_CLOEXEC, 0); posix_spawn_file_actions_addfchdir(, 5); modulo any issues with running out of available fds. Since the existing Solaris implementation uses const char* for the _addchdir() name, we'd definitely want to spell things as addfchdir() for an int version rather than risk confusion why addchdir() takes a different type than addchdir_n(). But with that said, here's an exploratory patch originally proposed to glibc implementing an fchdir action under the name addchdir() (but which never went anywhere at the time) - 8 years ago! https://sourceware.org/ml/libc-alpha/2010-08/msg00107.html Issue History Date ModifiedUsername FieldChange == 2018-09-07 18:39 eblake New Issue 2018-09-07 18:39 eblake Name => Eric Blake 2018-09-07 18:39 eblake Organization => Red Hat 2018-09-07 18:39 eblake User Reference=> posix_spawn.chdir 2018-09-07 18:39 eblake Section => posix_spawn 2018-09-07 18:39 eblake Page Number => 1452 ff. 2018-09-07 18:39 eblake Line Number => 48227 ff. 2018-09-07 18:39 eblake Interp Status => --- 2018-09-07 18:39 eblake Relationship added related to 0001044 2018-09-07 18:44 eblake Desired Action Updated 2018-09-07 18:46 eblake Desired Action Updated 2018-09-07 18:49 eblake Desired Action Updated 2018-09-07 18:51 eblake Desired Action Updated 2018-09-07 18:53 eblake Desired Action Updated 2018-09-07 18:55 eblake Desired Action Updated 2018-09-07 18:55 eblake Tag Attached: issue8 2018-09-07 19:02 eblake Note Added: 0004109 2018-09-07 19:04 eblake Desired Action Updated 2018-09-07 19:29 eblake Desired Action Updated 2018-09-07 19:35 eblake Description Updated 2018-09-07 22:18 eblake Note Added: 0004110 2018-09-07 22:44 eblake Note Added: 0004111 ==
Re: [RFC/PATCH glibc 0/2] setting working dir in posix_spawn()
[reviving a REALLY old thread]
https://sourceware.org/ml/libc-alpha/2010-08/msg00107.html
On 08/27/2010 01:35 AM, Jonathan Nieder wrote:
(pruned cc's, +cc:libc-alpha)
Eric Blake wrote:
On 08/26/2010 12:18 AM, Jonathan Nieder wrote:
Do you think there would be any interest in a posix_spawn() variant
that takes a dir parameter? I am imagining something like this:
Of your variants, I would most prefer:
int posix_spawn_file_actions_addchdir(posix_spawn_file_actions_t
*file_actions, int dirfd);
Today, I just submitted http://austingroupbugs.net/view.php?id=1208,
then in searching my mail archives, I found this related thread that
never had a response at the time, so I'm now offering a reply. Compared
to my thoughts 8 years ago, my new writeup proposed
int posix_spawn_file_actions_addchdir(posix_spawn_file_actions_t
*restrict file_actions, const char *restrict name);
int posix_spawn_file_actions_addfchdir(posix_spawn_file_actions_t
*file_actions, int dirfd);
which is slightly different from your RFC based on my older thoughts.
But in re-reading your email, I see that we could indeed get by with
JUST the fchdir() signature, since chdir("foo") can generally be
decomposed into fchdir(open("foo", O_RDONLY|O_DIRECTORY)).
Okay, here's a proof of concept (for the easy case --- a fork()-
based implementation for Linux). Patches apply to 8b2b771^.
For that matter, it may also be worth adding
posix_spawn_file_actions_addopenat, which mirrors the recent
addition of openat() semantics.
Sounds like a good idea. I did not try it because I did not want to
think about whether it would cause the __spawn_action struct to grow
(and if so, what ramifications that would have, if any).
Also, I've realized that we do NOT need
posix_spawn_file_actions_addopenat(). The main benefit of openat() is
that you can redirect relative file names according to an fd of your
choice, without affecting global state. But during posix_spawn(), there
are no other threads competing for global state (if you are doing a
library implementation where the chdir() is done between fork() and
exec()), so:
openat(mydir, "file", mode);
can be decomposed to:
posix_spawn_file_actions_addopen(, 5, ".", O_RDONLY|O_DIRECTORY, 0);
posix_spawn_file_actions_addfchdir(, mydir);
posix_spawn_file_actions_addopen(, 4, "file", mode, 0);
posix_spawn_file_actions_addfchdir(, 5);
posix_spawn_file_actions_addclose(, 5);
We don't need to add posix_spawn_file_actions_addFOO for every possible
FOO that typically gets called between fork/exec, as long as we can
string together enough bare components to get the feature parity within
the single-threaded context of posix_spawn() for what is otherwise
expensive if done in the parent as a wrapper around posix_spawn(), even
if it adds more verbosity into the posix_spawn_* calls require to get
the same desired effects.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
