Messages in this thread | | | Date | Fri, 28 Aug 2015 11:31:54 +0800 | Subject | Re: [PATCH] kernel/sysctl.c: If "count" including the terminating byte '\0' the write system call should retrun success. | From | Sean Fu <> |
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On Thu, Aug 27, 2015 at 4:32 PM, Sean Fu <fxinrong@gmail.com> wrote: > On Thu, Aug 27, 2015 at 10:32 AM, Steven Rostedt <rostedt@goodmis.org> wrote: >> On Thu, 27 Aug 2015 08:17:29 +0800 >> Sean Fu <fxinrong@gmail.com> wrote: >> >>> On Thu, Aug 27, 2015 at 4:36 AM, Steven Rostedt <rostedt@goodmis.org> wrote: >>> > On Wed, 26 Aug 2015 23:48:01 +0800 >>> > Sean Fu <fxinrong@gmail.com> wrote: >>> > >>> > >>> >> > Defending the patch, I can't imagine any user space code expecting the >>> >> > current behavior. The current behavior is that if you write "1\0" it >>> >> > will error out instead of accepting the "1". I can't come up with a >>> >> > scenario that would require userspace to expect "1\0" to fail. Can you? >>> >> Thanks >>> > >>> > Although, with the current patch, would "1\02" fail? It should. >>> Yes, "1\02" is equal to "1\2"(count=2) or "1\2\0"(count=3), So it should fail. >> >> Sorry, I meant "1\0 2" > In this case, The patch behavior is accepting the "1" and discarding > other bytes. > for (; left && vleft--; i++, first=0) { //vleft is 1 for integer > type or unsigned long type proc file > >> >> -- Steve >> >>> >>> code >>> len = write(fd, "1\0\2", 3); >>> >>> strace execute result: >>> write(3, "1\2\0", 3) = -1 EINVAL (Invalid argument) If vleft > 1, "1\0 2" is treated as invalid paraments and all string include '\0' will be invalid.
>>> >>> > >>> > -- Steve >>
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