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ptrace.2: Minor fixes 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2013-02-16 10:22:49 +01:00
parent ba8f446e0b
commit f04ba477c4
1 changed files with 24 additions and 16 deletions
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40
man2/ptrace.2
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@ -42,7 +42,7 @@
.\" (Thanks to Blaisorblade, Daniel Jacobowitz and others who helped.)
.\" 2011-09, major update by Denys Vlasenko <vda.linux@googlemail.com>
.\"
.TH PTRACE 2 2013-01-27 "Linux" "Linux Programmer's Manual"
.TH PTRACE 2 2013-02-16 "Linux" "Linux Programmer's Manual"
.SH NAME
ptrace \- process trace
.SH SYNOPSIS
@ -238,22 +238,23 @@ are not present on all architectures.
.BR PTRACE_GETREGSET " (since Linux 2.6.34)"
Read the tracee's registers.
.I addr
specifies, in an architecture-dependent way, the type of registers to be read.
specifies, in an architecture-dependent way, the type of registers to be read.
.B NT_PRSTATUS
(with numerical value 1)
usually results in reading of general-purpose registers. If CPU has, for example,
usually results in reading of general-purpose registers.
If the CPU has, for example,
floating-point and/or vector registers, they can be retrieved by setting
.I addr
to corresponding
to the corresponding
.B NT_foo
constant.
.I data
points to a
.BR "struct iovec" ,
which describes destination buffer's location and length.
On return, kernel modifies
which describes ithe destination buffer's location and length.
On return, the kernel modifies
.B iov.len
to indicate actual number of bytes returned.
to indicate the actual number of bytes returned.
.TP
.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
Retrieve information about the signal that caused the stop.
@ -293,7 +294,8 @@ and
are not present on all architectures.
.TP
.BR PTRACE_SETREGSET " (since Linux 2.6.34)"
Modify the tracee's registers. The meaning of
Modify the tracee's registers.
The meaning of
.I addr
and
.I data
@ -559,7 +561,9 @@ supported only on x86.
.BR PTRACE_LISTEN " (since Linux 3.4)"
Restart the stopped tracee, but prevent it from executing.
The resulting state of the tracee is similar to a process which
has been stopped by a SIGSTOP (or other stopping signal).
has been stopped by a
.B SIGSTOP
(or other stopping signal).
See the "group-stop" subsection for additional information.
.B PTRACE_LISTEN
only works on tracees attached by
@ -594,9 +598,10 @@ directly has no such limitation.
.\" instead of describing (and needing to support) PTRACE_KILL's quirks.]
.TP
.BR PTRACE_INTERRUPT " (since Linux 3.4)"
Stop a tracee. If tracee is running, it will stop with
Stop a tracee.
If the tracee is running, it will stop with
.BR PTRACE_EVENT_STOP .
If tracee is already stopped by a signal, or receives a signal
If the tracee is already stopped by a signal, or receives a signal
in parallel with
.BR PTRACE_INTERRUPT ,
it may report a group-stop
@ -641,7 +646,8 @@ making it a tracee of the calling process.
Unlike
.BR PTRACE_ATTACH ,
.B PTRACE_SEIZE
does not stop the process. Only
does not stop the process.
Only a
.BR PTRACE_SEIZE d
process can accept
.B PTRACE_INTERRUPT
@ -1040,7 +1046,7 @@ then it is definitely a group-stop.
.B SIGKILL
killed the tracee.)
.LP
As of kernel 2.6.38,
As of Linux 2.6.38,
after the tracer sees the tracee ptrace-stop and until it
restarts or kills it, the tracee will not run,
and will not send notifications (except
@ -1063,12 +1069,14 @@ this would cause the
.B SIGCONT
signals to have no effect on the tracee.
.LP
Since kernel 3.4, there is a method to overcome this problem: instead of
Since Linux 3.4, there is a method to overcome this problem: instead of
.BR PTRACE_CONT ,
a
.B PTRACE_LISTEN
command can be used to restart a tracee in a way where it does not execute,
but waits for a new event which it can report via waitpid (such as when
but waits for a new event which it can report via
.BR waitpid (2)
(such as when
it is restarted by a
.BR SIGCONT ).
.SS PTRACE_EVENT stops
@ -1430,7 +1438,7 @@ and the tracer usually suppresses it, this may cause a stray
return from the currently executing system call in the tracee,
as described in the "Signal injection and suppression" section.
.LP
Since kernel 3.4,
Since Linux 3.4,
.B PTRACE_SEIZE
can be used instead of
.BR PTRACE_ATTACH .