>Number: 158206 >Category: misc >Synopsis: /bin/sh doesn't properly return IO errors to conditionals in a >script >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Jun 23 16:10:14 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Chris Ulrich >Release: amd64 freebsd 8.2-RELEASE >Organization: CSN Stores >Environment: FreeBSD svn.csnzoo.com 8.2-RELEASE FreeBSD 8.2-RELEASE #0: Thu Feb 17 02:41:51 UTC 2011 [email protected]:/usr/obj/usr/src/sys/GENERIC amd64 >Description: a /bin/sh script writing to a closed file descriptor doesn't pass the IO error it receives from the write to the script itself.
>How-To-Repeat: write these two scripts: #!/bin/sh while echo -n . ; do : ; done and #!/bin/sh while printf . ; do : ; done now run each script with std-out closed, ie (assuming your interactive shell is bourne shell or similar): $ sh ./bomb-echo.sh >&- or $ sh ./bomb-printf.sh >&- both should exit instantly because echo *should* get an error from writing to a closed file descriptor. Instead both spin madly until they get a kill signal or you truss them (the last bit of stuff you see when you truss them is: 72238: sigprocmask(SIG_SETMASK,0x0,0x0) = 0 (0x0) 72238: write(1,".",1) ERR#9 'Bad file descriptor' 72238: process exit, rval = 0 which itself is another >Fix: sorry. don't know C. >Release-Note: >Audit-Trail: >Unformatted: _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "[email protected]"
