.TH PTRACE 2
.SH NAME
ptrace \- ptrace system call. 
.SH SYNOPSIS
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#include <sys/ptrace.h>

long ptrace( int req, pid_t pid, long addr, long data)

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.SH DESCRIPTION
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Ptrace(2) is called with following arguments:
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.br
req
request
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pid 
process id
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addr
address
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data
data
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.SH REQUESTS
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.I
T_STOP
stop the process.
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T_OK
enable tracing by parent for this process. 
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.I
T_GETINS
return value from instruction space 
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T_GETDATA
return value from data space. 
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T_GETUSER
return value from process table. See proc.h in kernel.
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T_SETINS
set value from instruction space. 
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T_SETDATA
set value from data space.
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T_SETUSER
set value in process table. 
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T_RESUME
resume execution.
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T_EXIT
exit. Turn off tracing.
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.I
T_STEP
set trace bit to enable single step.
.SH "SEE ALSO"
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mdb(1)
.SH DIAGNOSTICS
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errno is set by ptrace().
.SH FILES
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/usr/src/kernel/proc.h for process table info.