View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000692 | 1003.1(2013)/Issue7+TC1 | System Interfaces | public | 2013-05-07 17:57 | 2019-06-10 08:55 |
| Reporter | mdempsky | Assigned To | |||
| Priority | normal | Severity | Editorial | Type | Enhancement Request |
| Status | Closed | Resolution | Accepted As Marked | ||
| Name | Matthew Dempsky | ||||
| Organization | OpenBSD | ||||
| User Reference | |||||
| Section | XSI 2.4.3 Signal Actions | ||||
| Page Number | 494 | ||||
| Line Number | 16845 | ||||
| Interp Status | Approved | ||||
| Final Accepted Text | see 0000692:0001609 | ||||
| Summary | 0000692: More async-signal-safe functions | ||||
| Description | It's very tedious to not have access to functions like memcpy() and strlen() in an async signal handler. It would ease application developers if they didn't have to reimplement these functions themselves. | ||||
| Desired Action | Add the following functions to the table of async-signal-safe functions: memccpy, memchr, memcmp, memcpy, memmove, memset, stpcpy, stpncpy, strcat, strchr, strcmp, strcpy, strcspn, strlen, strncat, strncmp, strncpy, strnlen, strpbrk, strrchr, strspn, strstr, strtok_r Alternatively, add a note explaining why these functions aren't async-signal-safe. | ||||
| Tags | tc2-2008 | ||||
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Oops, Eric Blake points out the second "strchr" in the list should actually be "strrchr". |
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The Desired Action has been updated as suggested in 0000692:0001592. |
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It might be worth scrubbing for other functions which don't alter errno, and don't depend on or alter global state, where the result is always determined solely by the parameters. For example, <strings.h> ffs() seems like something useful to declare async-signal safe, and is the sort of bit-twiddling operation that might actually be useful in a signal handler. Likewise for <arpa/inet.h> with ntohl, ntohs, htonl, htons. The proposal of <endian.h> in 0000162 would add another set of candidates. |
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Interpretation response ------------------------ The standard states that various string functions are not async-signal-safe, and therefore must not be used in signal handlers or between fork and exec in a multithreaded program, and conforming applications must conform to this. However, concerns have been raised about this which are being referred to the sponsor. Rationale: ---------- Since these functions do not modify or depend on global state, there are no known implementations where these functions cannot be safely used in aysnc-signal-safe code. Notes to the Editor (not part of this interpretation): ------------------------------------------------------- At page 494 line 16845-16879 [XSH 2.4.3 table of async-signal-safe functions], add the following in proper sorted order: ffs, htonl, htons, memccpy, memchr, memcmp, memcpy, memmove, memset, ntohl, ntohs, stpcpy, stpncpy, strcat, strchr, strcmp, strcpy, strcspn, strlen, strncat, strncmp, strncpy, strnlen, strpbrk, strrchr, strspn, strstr, strtok_r, wcpcpy, wcpncpy, wcscat, wcschr, wcscmp, wcscpy, wcscspn, wcslen, wcsncat, wcsncmp, wcsncpy, wcsnlen, wcspbrk, wcsrchr, wcsspn, wcsstr, wcstok, wmemchr, wmemcmp, wmemcpy, wmemmove, wmemset |
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Interpretation Proposed 6 Sep 2013 |
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Interpretation approved 14 October 2013 |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2013-05-07 17:57 | mdempsky | New Issue | |
| 2013-05-07 17:57 | mdempsky | Name | => Matthew Dempsky |
| 2013-05-07 17:57 | mdempsky | Organization | => OpenBSD |
| 2013-05-07 17:57 | mdempsky | Section | => XSI 2.4.3 Signal Actions |
| 2013-05-07 18:05 | mdempsky | Note Added: 0001592 | |
| 2013-05-07 18:25 | Don Cragun | Interp Status | => --- |
| 2013-05-07 18:25 | Don Cragun | Desired Action Updated | |
| 2013-05-07 18:26 | Don Cragun | Note Added: 0001593 | |
| 2013-05-07 19:15 | eblake | Note Added: 0001594 | |
| 2013-05-16 16:30 | eblake | Note Added: 0001609 | |
| 2013-05-16 16:34 | eblake | Note Edited: 0001609 | |
| 2013-05-16 16:35 | eblake | Note Edited: 0001609 | |
| 2013-05-16 16:36 | eblake | Page Number | => 494 |
| 2013-05-16 16:36 | eblake | Line Number | => 16845 |
| 2013-05-16 16:36 | eblake | Interp Status | --- => Pending |
| 2013-05-16 16:36 | eblake | Final Accepted Text | => see 0000692:0001609 |
| 2013-05-16 16:36 | eblake | Status | New => Interpretation Required |
| 2013-05-16 16:36 | eblake | Resolution | Open => Accepted As Marked |
| 2013-05-16 16:36 | eblake | Tag Attached: tc2-2008 | |
| 2013-05-16 16:36 | eblake | Relationship added | related to 0000162 |
| 2013-09-06 04:56 | ajosey | Interp Status | Pending => Proposed |
| 2013-09-06 04:56 | ajosey | Note Added: 0001811 | |
| 2013-10-14 13:06 | ajosey | Interp Status | Proposed => Approved |
| 2013-10-14 13:06 | ajosey | Note Added: 0001890 | |
| 2019-06-10 08:55 | agadmin | Status | Interpretation Required => Closed |
