fake_execve() called before trace process (child) ready (strace-4.5.8, LINUX(#ifndef USE_PROCFS))
ptushnik at gmail.com
Thu Nov 18 06:44:03 UTC 2004
I'v found issue, that fake_execve() called before trace process (child) ready.
It is not important in common use, because fake_execve() just print
pretty formatted line (with argc, argv and environ). But if we pass
"-i" arg to strace, fake_execve() -> printleader() -> if(iflag)
->printcall() try to determine "Instruction Pointer" by calling
upeek() -> ptrace(PTRACE_PEEKUSER, ...). And very often (on fast CPU)
ptrace() fail in case that trace process (child) not ready for it.
$ strace -i cat /dev/null
upeek: ptrace(PTRACE_PEEKUSER,13426,48,0): No such process
[????????] execve("/bin/cat", ["cat", "/dev/null"], [/* 37 vars */]) = 0
My solution is remove fake_execve() function call and insert
kill(getpid(), SIGSTOP) function before execve(TARGET_BIN,....).
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