* ptrace(PTRACE_SYSCALL) and data field
@ 2009-03-18 3:46 Mike Frysinger
[not found] ` <200903172346.32372.vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
0 siblings, 1 reply; 10+ messages in thread
From: Mike Frysinger @ 2009-03-18 3:46 UTC (permalink / raw)
To: linux-man-u79uwXL29TY76Z2rM5mHXA
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the ptrace(2) page doesnt say anything about the data field (ignored or
otherwise). it seems to be ignored, but i didnt trace the kernel
exhaustively. the examples found via google shows that it's ignored. strace
usage seems odd (it passes in an irrelevant pointer), which would indicate
it's ignored as well ...
-mike
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <200903172346.32372.vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org> @ 2009-03-29 22:00 ` Michael Kerrisk [not found] ` <cfd18e0f0903291500s42eb323nd0d9ab8c1f7c4dbc-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2009-03-30 0:38 ` Michael Kerrisk 1 sibling, 1 reply; 10+ messages in thread From: Michael Kerrisk @ 2009-03-29 22:00 UTC (permalink / raw) To: Mike Frysinger; +Cc: linux-man-u79uwXL29TY76Z2rM5mHXA, Roland McGrath Hi Mike, (Roland may be able to help out here.) On Wed, Mar 18, 2009 at 4:46 PM, Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org> wrote: > the ptrace(2) page doesnt say anything about the data field (ignored or > otherwise). it seems to be ignored, but i didnt trace the kernel > exhaustively. the examples found via google shows that it's ignored. strace > usage seems odd (it passes in an irrelevant pointer), which would indicate > it's ignored as well ... It's true that this looks like a defect in the man page. But I'm not sure what the fix is. In the kernel source file kernel/ptrace.c, function ptrace_resume() we have the line child->exit_code = data; which seems to be executed by the PRACE_SYSCALL code path. That implies that data is treated as a signal number (like PTRACE_CONT). That seems consistent with the following in the strace.c source file of strace(1): if (ptrace(PTRACE_SYSCALL, pid, (char *) 1, WSTOPSIG(status)) < 0) { perror("trace: ptrace(PTRACE_SYSCALL, ...)"); cleanup(); return -1; } Did I misunderstand something? Your thoughts? Cheers, Michael -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <cfd18e0f0903291500s42eb323nd0d9ab8c1f7c4dbc-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> @ 2009-03-29 22:35 ` Roland McGrath [not found] ` <20090329223508.4521DFC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> 0 siblings, 1 reply; 10+ messages in thread From: Roland McGrath @ 2009-03-29 22:35 UTC (permalink / raw) To: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA All of the "resuming" ptracer requests treat the data argument the same. Those are PTRACE_CONT, PTRACE_SYSCALL, PTRACE_*STEP, PTRACE_SYSEMU*. The data argument is either 0 or a signal number. The addr argument is ignored by all these. Roland -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <20090329223508.4521DFC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> @ 2009-03-29 22:47 ` Michael Kerrisk [not found] ` <cfd18e0f0903291547s75749b01icbf99b6eab335cce-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 0 siblings, 1 reply; 10+ messages in thread From: Michael Kerrisk @ 2009-03-29 22:47 UTC (permalink / raw) To: Roland McGrath; +Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA On Mon, Mar 30, 2009 at 11:35 AM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: > All of the "resuming" ptracer requests treat the data argument the same. > Those are PTRACE_CONT, PTRACE_SYSCALL, PTRACE_*STEP, PTRACE_SYSEMU*. > The data argument is either 0 or a signal number. > The addr argument is ignored by all these. Thanks for jumping in Roland. So, for PTRACE_SYSCALL, the sameantics are like PTRACE_CONT, that is, it is interpreted as a signal to be sent to the child. Right? Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <cfd18e0f0903291547s75749b01icbf99b6eab335cce-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> @ 2009-03-29 23:34 ` Roland McGrath [not found] ` <20090329233402.9C695FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> 0 siblings, 1 reply; 10+ messages in thread From: Roland McGrath @ 2009-03-29 23:34 UTC (permalink / raw) To: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA > On Mon, Mar 30, 2009 at 11:35 AM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: > > All of the "resuming" ptracer requests treat the data argument the same. > > Those are PTRACE_CONT, PTRACE_SYSCALL, PTRACE_*STEP, PTRACE_SYSEMU*. > > The data argument is either 0 or a signal number. > > The addr argument is ignored by all these. > > Thanks for jumping in Roland. > > So, for PTRACE_SYSCALL, the sameantics are like PTRACE_CONT, that is, > it is interpreted as a signal to be sent to the child. Right? For all those requests, yes. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <20090329233402.9C695FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> @ 2009-03-29 23:43 ` Michael Kerrisk 2009-03-29 23:54 ` Michael Kerrisk 1 sibling, 0 replies; 10+ messages in thread From: Michael Kerrisk @ 2009-03-29 23:43 UTC (permalink / raw) To: Roland McGrath; +Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA On Mon, Mar 30, 2009 at 12:34 PM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: >> On Mon, Mar 30, 2009 at 11:35 AM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: >> > All of the "resuming" ptracer requests treat the data argument the same. >> > Those are PTRACE_CONT, PTRACE_SYSCALL, PTRACE_*STEP, PTRACE_SYSEMU*. >> > The data argument is either 0 or a signal number. >> > The addr argument is ignored by all these. >> >> Thanks for jumping in Roland. >> >> So, for PTRACE_SYSCALL, the sameantics are like PTRACE_CONT, that is, >> it is interpreted as a signal to be sent to the child. Right? > > For all those requests, yes. Thanks for the confirmation, Roland. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <20090329233402.9C695FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> 2009-03-29 23:43 ` Michael Kerrisk @ 2009-03-29 23:54 ` Michael Kerrisk [not found] ` <cfd18e0f0903291654uea58687x5fb16d0b794e69cf-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 1 sibling, 1 reply; 10+ messages in thread From: Michael Kerrisk @ 2009-03-29 23:54 UTC (permalink / raw) To: Roland McGrath; +Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA On Mon, Mar 30, 2009 at 12:34 PM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: >> On Mon, Mar 30, 2009 at 11:35 AM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: >> > All of the "resuming" ptracer requests treat the data argument the same. >> > Those are PTRACE_CONT, PTRACE_SYSCALL, PTRACE_*STEP, PTRACE_SYSEMU*. >> > The data argument is either 0 or a signal number. >> > The addr argument is ignored by all these. >> >> Thanks for jumping in Roland. >> >> So, for PTRACE_SYSCALL, the sameantics are like PTRACE_CONT, that is, >> it is interpreted as a signal to be sent to the child. Right? > > For all those requests, yes. Hmmm. The existing man page includes this text: PTRACE_SYSEMU, PTRACE_SYSEMU_SINGLESTEP (since Linux 2.6.14) ... (addr and data are ignored; ... which according to what you've said (and also according to my reading of the source), is wrong. Correct? Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <cfd18e0f0903291654uea58687x5fb16d0b794e69cf-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> @ 2009-03-30 0:07 ` Roland McGrath [not found] ` <20090330000712.C0B54FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> 0 siblings, 1 reply; 10+ messages in thread From: Roland McGrath @ 2009-03-30 0:07 UTC (permalink / raw) To: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA > Hmmm. The existing man page includes this text: > > PTRACE_SYSEMU, PTRACE_SYSEMU_SINGLESTEP (since Linux 2.6.14) > ... > (addr and data are ignored; ... > > which according to what you've said (and also according to my reading > of the source), is wrong. Correct? Yes, those also treat the signal argument like PTRACE_CONT et al. Thanks, Roland -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <20090330000712.C0B54FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org> @ 2009-03-30 0:31 ` Michael Kerrisk 0 siblings, 0 replies; 10+ messages in thread From: Michael Kerrisk @ 2009-03-30 0:31 UTC (permalink / raw) To: Roland McGrath; +Cc: Mike Frysinger, linux-man-u79uwXL29TY76Z2rM5mHXA On Mon, Mar 30, 2009 at 1:07 PM, Roland McGrath <roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote: >> Hmmm. The existing man page includes this text: >> >> PTRACE_SYSEMU, PTRACE_SYSEMU_SINGLESTEP (since Linux 2.6.14) >> ... >> (addr and data are ignored; ... >> >> which according to what you've said (and also according to my reading >> of the source), is wrong. Correct? > > Yes, those also treat the signal argument like PTRACE_CONT et al. Thanks! -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: ptrace(PTRACE_SYSCALL) and data field [not found] ` <200903172346.32372.vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org> 2009-03-29 22:00 ` Michael Kerrisk @ 2009-03-30 0:38 ` Michael Kerrisk 1 sibling, 0 replies; 10+ messages in thread From: Michael Kerrisk @ 2009-03-30 0:38 UTC (permalink / raw) To: Mike Frysinger; +Cc: linux-man-u79uwXL29TY76Z2rM5mHXA, Roland McGrath On Wed, Mar 18, 2009 at 4:46 PM, Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org> wrote: > the ptrace(2) page doesnt say anything about the data field (ignored or > otherwise). it seems to be ignored, but i didnt trace the kernel > exhaustively. the examples found via google shows that it's ignored. strace > usage seems odd (it passes in an irrelevant pointer), which would indicate > it's ignored as well ... > -mike Mike, For man-pages-3.20, I've upated the PTRACE_SYSCALL documentation to note that 'data' is used as for PTRACE_CONT. I've also added similar text to PTRAC_SYSEMU*. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 10+ messages in thread
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2009-03-18 3:46 ptrace(PTRACE_SYSCALL) and data field Mike Frysinger
[not found] ` <200903172346.32372.vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>
2009-03-29 22:00 ` Michael Kerrisk
[not found] ` <cfd18e0f0903291500s42eb323nd0d9ab8c1f7c4dbc-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-03-29 22:35 ` Roland McGrath
[not found] ` <20090329223508.4521DFC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org>
2009-03-29 22:47 ` Michael Kerrisk
[not found] ` <cfd18e0f0903291547s75749b01icbf99b6eab335cce-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-03-29 23:34 ` Roland McGrath
[not found] ` <20090329233402.9C695FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org>
2009-03-29 23:43 ` Michael Kerrisk
2009-03-29 23:54 ` Michael Kerrisk
[not found] ` <cfd18e0f0903291654uea58687x5fb16d0b794e69cf-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-03-30 0:07 ` Roland McGrath
[not found] ` <20090330000712.C0B54FC2A8-nL1rrgvulkc2UH6IwYuUx0EOCMrvLtNR@public.gmane.org>
2009-03-30 0:31 ` Michael Kerrisk
2009-03-30 0:38 ` Michael Kerrisk
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