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Re: File descriptor 5 is held open

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On Saturday, January 6, 1996 at 2:00:00 PM UTC+6, Lloyd Parkes wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: alpha
> OS: OSF1
> Compiler: cc -migrate
> Compilation CFLAGS:  -DHAVE_SETLINEBUF -DHAVE_VFPRINTF -DHAVE_UNISTD_H -DHAVE_STDLIB_H -DHAVE_LIMITS_H  -DHAVE_GETGROUPS -DHAVE_RESOURCE -DHAVE_SYS_PARAM -DVOID_SIGHANDLER -DNLS -D_BSD -DHAVE_WAIT_H  -DHAVE_GETWD -DHAVE_DUP2 -DHAVE_STRERROR  -DHAVE_DIRENT_H -DHAVE_STRING_H  -DHAVE_VARARGS_H -DHAVE_STRCHR    -Dalpha -DOSF1 -DSHELL  -DHAVE_ALLOCA_H   -O4
> uname output: OSF1 pukatea.its.vuw.ac.nz V3.2 148 alpha
> 
> Bash Version: 1.14
> Patch Level: 5
> 
> Description:
>         When bash execs another program, the new program inherits an
> open file descriptor. File descriptor #5 to be precise. This file
> descriptor is open for reading and under various circumstances the new
> program will block waiting for input on that descriptor. I have seen
> this before on other platforms, but now is is becoming a pain in the
> neck, rather than just a bash foible.
> 
> Repeat-By:
> Take a minimal program e.g.
> 
> 	main ()
> 	{
> 	 sleep (3000);
> 	}
> 
> Compile it and run it under gdb. I use GDB 4.14
> (alpha-dec-osf3.0). Before the sleep terminates, interrupt the
> program. The gdb prompt will appear. Type the quit command. Gdb will
> ask you if you are sure because the program is still running. Type 'y'
> and then press enter. Gdb now hangs. You can interrupt gdb and it will
> terminate. 
> 
> You can now use ps to look for the process that was being
> debugged. You should find that it is blocked waiting for tty
> input. e.g. 
> 
> 	  PID TTY      S           TIME COMMAND
> 	19779 ttyp3    T        0:00.11 /u/its/lloyd/tmp/a.out
> 
> I have seen similar behaviour from rsh when used the the X11R5/R6
> program xon. I have seen this sort of behaviour on NetBSD/i386,
> NetBSD/sparc, SunOS 4, and Irix (these are all from memory though).

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Re: File descriptor 5 is held open mishurahman713@gmail.com - 2020-07-18 03:34 -0700

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