86 lines
3.3 KiB
Plaintext
86 lines
3.3 KiB
Plaintext
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========================================================================
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This is the unmodified README from Paul Kranenburg's release of strace
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for SunOS 4.1.x. Some of the notes and instructions are no longer valid
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however the file has been retained for its historical value. -- jrs
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========================================================================
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/*
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* @(#)README 2.4 92/01/21
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*
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* Copyright (C) 1991 Paul Kranenburg.
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*
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* Please send comments, enhancements or any other useful ideas to
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* the address at the end of this file.
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*
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*/
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strace(1) is a system call tracer for Sun(tm) systems much like the
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Sun supplied program trace(1). strace(1) is a useful utility to sort
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of debug programs for which no source is available which unfortunately
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includes almost all of the Sun supplied system software.
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Like trace(1), strace displays each system call and its arguments as it
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is invoked by the traced process, but tries to do a better job of
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decoding the arguments, displaying them in symbolic format whenever
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possible. Passed structures/character arrays are read from the process'
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address space and displayed in an appropriate format.
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It is also possible to instruct strace to trace child processes as
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they are created by the fork(2) system call. However, this is slightly
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involved for two reasons: 1) the trace flag is cleared in the child
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process by the fork system call, so we must make a special effort to
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gain control of the child (see NOTES below), 2) our tracing manipulations
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of the child may interfere with a possible wait(2) system call executed
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by the (also traced) parent process. In this case we don't allow the parent
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to continue until one of its children enters a state that may cause the
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parent's wait(2) call to return.
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NOTES.
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o Not all system calls have been implemented yet as described
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above (see dummy.h for a list), these calls only have their args
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displayed as hex numbers.
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o The program draws heavily on Sun's extensions to the ptrace(2)
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system call.
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o This release is based upon SunOS 4.1.1. The syscall list (syscall.h)
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and ioctl's (ioctlent.m4) are probably most critically dependant
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on the OS version (see also /sys/os/init_sysent.c).
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You may have to edit `ioctlsort.c' and/or `ioctlent.m4' to get
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`ioctlsort.c' to compile with your suite of system header files.
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o The way in which child processes are caught and attached to after
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the fork() call is Sparc-specific (in fact it has the looks of a
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terrible hack). Also, this trick won't work with vfork(2).
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Enhancements are sollicited for.
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o Dynamically linked executables can be convinced to use the fork(2)
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system call in stead of vfork(2) by modifying their (internal)
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symbol table immediately after such a program is exec'ed. Be
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warned that programs which depend on vfork's peculiar semantics
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may not run as expected. Enable by the `-F' switch.
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INSTALLATION.
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Edit the paths in the Makefile to suit your local system.
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Enter the usual make commands (`make debug' to enable the
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compiler `-g' flag).
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Not all sites have a complete set of include files, depending
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on the selected software categories at OS install time. The
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makefile tries to detect the presence of the Sunview category,
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if other files are missing you may have to edit `ioctlent.h'.
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COMMENTS TO:
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P. Kranenburg
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Department of Computer Science
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Erasmus University Rotterdam
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P.O. Box 1738
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NL-3000 DR Rotterdam
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e-mail: pk@cs.few.eur.nl
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