[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
The following issue has a resolution that has been APPLIED. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: Applied Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text:See Desired Action Resolution: Accepted Fixed in Version: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2019-11-05 12:01 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 2017-06-10 02:13 dancol Note Added: 0003757 2017-06-12 09:18 geoffclare Note Added: 0003759 2018-07-24 17:53 dancol Note Added: 0004059 2018-07-25 08:44 geoffclare Note Added: 0004060 2018-10-25 16:25 nick Interp Status => --- 2018-10-25 16:25 nick Final Accepted Text => See Desired Action 2018-10-25 16:25 nick Status New => Resolved 2018-10-25 16:25 nick Resolution Open => Accepted 2018-10-25 16:25 nick Tag Attached: tc3-2008 2019-11-05 12:01 geoffclare Status Resolved => Applied ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
The following issue has been RESOLVED. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: Resolved Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text:See Desired Action Resolution: Accepted Fixed in Version: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2018-10-25 16:25 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 2017-06-10 02:13 dancol Note Added: 0003757 2017-06-12 09:18 geoffclare Note Added: 0003759 2018-07-24 17:53 dancol Note Added: 0004059 2018-07-25 08:44 geoffclare Note Added: 0004060 2018-10-25 16:25 nick Interp Status => --- 2018-10-25 16:25 nick Final Accepted Text => See Desired Action 2018-10-25 16:25 nick Status New => Resolved 2018-10-25 16:25 nick Resolution Open => Accepted ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2018-07-25 08:44 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == -- (0004060) geoffclare (manager) - 2018-07-25 08:44 http://austingroupbugs.net/view.php?id=1142#c4060 -- The weekly teleconferences have reached bug 1118, so a little way to go yet before this one gets its turn. Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 2017-06-10 02:13 dancol Note Added: 0003757 2017-06-12 09:18 geoffclare Note Added: 0003759 2018-07-24 17:53 dancol Note Added: 0004059 2018-07-25 08:44 geoffclare Note Added: 0004060 ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2018-07-24 17:53 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == -- (0004059) dancol (reporter) - 2018-07-24 17:53 http://austingroupbugs.net/view.php?id=1142#c4059 -- Ping? Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 2017-06-10 02:13 dancol Note Added: 0003757 2017-06-12 09:18 geoffclare Note Added: 0003759 2018-07-24 17:53 dancol Note Added: 0004059 ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2017-06-12 09:18 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == -- (0003759) geoffclare (manager) - 2017-06-12 09:18 http://austingroupbugs.net/view.php?id=1142#c3759 -- dancol, when this bug is reached in the weekly teleconferences, I expect that your proposed change will be accepted. There is nothing more you need to do. Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 2017-06-10 02:13 dancol Note Added: 0003757 2017-06-12 09:18 geoffclare Note Added: 0003759 ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2017-06-10 02:13 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == -- (0003757) dancol (reporter) - 2017-06-10 02:13 http://austingroupbugs.net/view.php?id=1142#c3757 -- shware_systems, in practice, pread and pwrite are direct system calls, so there are no particular userspace constraints preventing trivially (by definition) making these calls async-signal-safe. geoffclare, do you plan to change the standard to fix this omission? Is there anything you need me to do? Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 2017-06-10 02:13 dancol Note Added: 0003757 ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2017-06-06 13:48 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == -- (0003754) geoffclare (manager) - 2017-06-06 13:48 http://austingroupbugs.net/view.php?id=1142#c3754 -- The standard already requires pread() and pwrite() to be async-signal-safe. The fact that they are missing from the list in 2.4.3 is simply an editorial omission (and Daniel correctly classified this bug as such). This is because the description of pread() says "The pread() function shall be equivalent to read(), except that it shall read from a given position in the file without changing the file offset." In order for pread() not to be required to be async-signal-safe, the standard would instead have to say "The pread() function shall be equivalent to read(), except that it shall read from a given position in the file without changing the file offset and it need not be async-signal-safe." Likewise for pwrite(). Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 2017-06-06 13:48 geoffclare Note Added: 0003754 ==
Re: [1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
>-- > (0003753) shware_systems (reporter) - 2017-06-06 12:14 > http://austingroupbugs.net/view.php?id=1142#c3753 >-- >While this looks reasonable, the restriction on pread() and pwrite() of not >disturbing the seek position is problematic. It means an effective >dup();lseek();read() or write();close() sequence occurs on each invoke. This doesn't make sense: dup() creates a file pointer with: osame file pointer (that is, both file descriptors share one file pointer) lseek() on a dup()'ed file will move the lseek on the original file pointer as well. (That makes it possible to write an "lseek(1)" utility which can be used to change the file pointer for inherited file descriptors) Casper
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
A NOTE has been added to this issue. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2017-06-06 12:14 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe == -- (0003753) shware_systems (reporter) - 2017-06-06 12:14 http://austingroupbugs.net/view.php?id=1142#c3753 -- While this looks reasonable, the restriction on pread() and pwrite() of not disturbing the seek position is problematic. It means an effective dup();lseek();read() or write();close() sequence occurs on each invoke. While each of these operations is supposed to be asynch-safe, how they're combined, or implemented otherwise internally, may not be; so requiring this could break existing implementations. If the routines use malloc() to get space for temporary descriptors or buffers, as example, this would make the entire routine unsafe, since malloc() is also not in the safe list. Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions 2017-06-06 12:14 shware_systems Note Added: 0003753 ==
[1003.1(2016)/Issue7+TC2 0001142]: pread(2) and pwrite(2) should be async-signal-safe
The following issue has been SUBMITTED. == http://austingroupbugs.net/view.php?id=1142 == Reported By:dancol Assigned To: == Project:1003.1(2016)/Issue7+TC2 Issue ID: 1142 Category: Base Definitions and Headers Type: Omission Severity: Editorial Priority: normal Status: New Name: Daniel Colascione Organization: User Reference: Section:2.4.3 Signal Actions Page Number: Line Number: Interp Status: --- Final Accepted Text: == Date Submitted: 2017-06-03 23:42 UTC Last Modified: 2017-06-03 23:42 UTC == Summary:pread(2) and pwrite(2) should be async-signal-safe Description: Shouldn't pread(2) and pwrite(2) be, by analogy to read(2) and write(2), be marked as async-signal-safe? Without these facilities being available to signal handlers, concurrent IO (say, between two different signal handlers running concurrently in different threads) requires explicit synchronization (so as to avoid disturbing the file pointer via lseek(2)). This synchronization is itself awkward given only the set of primitives available in the async-signal-safety list. Desired Action: Add pread and pwrite to the list of async-signal-safe functions in section 2.4.3. == Issue History Date ModifiedUsername FieldChange == 2017-06-03 23:42 dancol New Issue 2017-06-03 23:42 dancol Name => Daniel Colascione 2017-06-03 23:42 dancol Section => 2.4.3 Signal Actions ==
