lroot@devvax.JPL.NASA.GOV (The Superuser) (02/05/88)
System: perl version 1.0 Patch #: 20 Priority: MEDIUM Subject: missing chop from example; system fails ungracefully. From: David L. Edwards <DLE@csl.sri.com> From: bdr@neti2.uucp (Brian Renaud) Description: The example of finding user names from the password file in the section on chown is missing a chop($user) to remove the newline; If system doesn't find the program to execute, the vforked child process thinks it's supposed to continue processing. Fix: From rn, say "| patch -p0 -N -d DIR", where DIR is your perl source directory. Outside of rn, say "cd DIR; patch -p0 -N <thisarticle". If you don't have the patch program, apply the following by hand, or get patch (version 2.0, latest patchlevel). After patching: make make test make install If patch indicates that patchlevel is the wrong version, you may need to apply one or more previous patches, or the patch may already have been applied. See the patchlevel.h file to find out what has or has not been applied. In any event, don't continue with the patch. If you are missing previous patches they can be obtained from me: Larry Wall lwall@jpl-devvax.jpl.nasa.gov If you send a mail message of the following form it will greatly speed processing: Subject: Command @SH mailpatch PATH perl 1.0 LIST ^ note the c where PATH is a return path FROM ME TO YOU in Internet notation, and LIST is the number of one or more patches you need, separated by spaces, commas, and/or hyphens. Saying 35- says everything from 35 to the end. You can also get the patches via anonymous FTP from jpl-devvax.jpl.nasa.gov (128.149.8.43). Index: patchlevel.h Prereq: 19 1c1 < #define PATCHLEVEL 19 --- > #define PATCHLEVEL 20 Index: arg.c Prereq: 1.0.1.8 *** arg.c.old Thu Feb 4 17:49:41 1988 --- arg.c Thu Feb 4 17:49:47 1988 *************** *** 1,6 **** ! /* $Header: arg.c,v 1.0.1.8 88/02/04 11:14:58 root Exp $ * * $Log: arg.c,v $ * Revision 1.0.1.8 88/02/04 11:14:58 root * patch18: regularized includes. * --- 1,9 ---- ! /* $Header: arg.c,v 1.0.1.9 88/02/04 17:47:31 root Exp $ * * $Log: arg.c,v $ + * Revision 1.0.1.9 88/02/04 17:47:31 root + * patch20: made failing fork/exec exit. + * * Revision 1.0.1.8 88/02/04 11:14:58 root * patch18: regularized includes. * *************** *** 2032,2038 **** value = (double)argflags; goto donumset; } ! /* FALL THROUGH */ case O_EXEC: if (arg[1].arg_flags & AF_SPECIAL) value = (double)do_aexec(arg); --- 2035,2046 ---- value = (double)argflags; goto donumset; } ! if (arg[1].arg_flags & AF_SPECIAL) ! value = (double)do_aexec(arg); ! else { ! value = (double)do_exec(str_get(sarg[1])); ! } ! _exit(-1); case O_EXEC: if (arg[1].arg_flags & AF_SPECIAL) value = (double)do_aexec(arg); Index: t/op.exec Prereq: 1.0 *** t/op.exec.old Thu Feb 4 17:50:21 1988 --- t/op.exec Thu Feb 4 17:50:22 1988 *************** *** 1,12 **** #!./perl ! # $Header: op.exec,v 1.0 87/12/18 13:13:26 root Exp $ $| = 1; # flush stdout ! print "1..4\n"; ! system "echo ok \\1"; # shell interpreted ! system "echo ok 2"; # split and directly called ! system "echo", "ok", "3"; # directly called ! exec "echo","ok","4"; --- 1,18 ---- #!./perl ! # $Header: op.exec,v 1.0.1.1 88/02/04 17:49:08 root Exp $ $| = 1; # flush stdout ! print "1..7\n"; ! print "not ok 1\n" if system "echo ok \\1"; # shell interpreted ! print "not ok 2\n" if system "echo ok 2"; # split and directly called ! print "not ok 3\n" if system "echo", "ok", "3"; # directly called ! if ((system "false") == 256) {print "ok 4\n";} else {print "not ok 4\n";} ! ! if ((system "lskdfj") == 255 * 256) {print "ok 5\n";} else {print "not ok 5\n";} ! ! unless (exec "lskdjfalksdjfdjfkls") {print "ok 6\n";} else {print "not ok 6\n";} ! ! exec "echo","ok","7"; Index: perl.man.1 Prereq: 1.0.1.2 *** perl.man.1.old Thu Feb 4 17:50:00 1988 --- perl.man.1 Thu Feb 4 17:50:02 1988 *************** *** 1,7 **** .rn '' }` ! ''' $Header: perl.man.1,v 1.0.1.2 88/01/30 17:04:07 root Exp $ ''' ''' $Log: perl.man.1,v $ ''' Revision 1.0.1.2 88/01/30 17:04:07 root ''' patch 11: random cleanup ''' --- 1,10 ---- .rn '' }` ! ''' $Header: perl.man.1,v 1.0.1.3 88/02/04 17:48:02 root Exp $ ''' ''' $Log: perl.man.1,v $ + ''' Revision 1.0.1.3 88/02/04 17:48:02 root + ''' patch20: added missing chop($user); to example in chown. + ''' ''' Revision 1.0.1.2 88/01/30 17:04:07 root ''' patch 11: random cleanup ''' *************** *** 862,867 **** --- 865,871 ---- print "User: "; $user = <stdin>; + chop($user); open(pass,'/etc/passwd') || die "Can't open passwd"; while (<pass>) { ($login,$pass,$uid,$gid) = split(/:/); Index: perl.man.2 Prereq: 1.0.1.3 *** perl.man.2.old Thu Feb 4 17:50:11 1988 --- perl.man.2 Thu Feb 4 17:50:14 1988 *************** *** 1,7 **** ''' Beginning of part 2 ! ''' $Header: perl.man.2,v 1.0.1.3 88/02/01 17:33:03 root Exp $ ''' ''' $Log: perl.man.2,v $ ''' Revision 1.0.1.3 88/02/01 17:33:03 root ''' patch12: documented split more adequately. ''' --- 1,10 ---- ''' Beginning of part 2 ! ''' $Header: perl.man.2,v 1.0.1.4 88/02/04 17:48:31 root Exp $ ''' ''' $Log: perl.man.2,v $ + ''' Revision 1.0.1.4 88/02/04 17:48:31 root + ''' patch20: documented return values of system better. + ''' ''' Revision 1.0.1.3 88/02/01 17:33:03 root ''' patch12: documented split more adequately. ''' *************** *** 401,408 **** Does exactly the same thing as \*(L"exec LIST\*(R" except that a fork is done first, and the parent process waits for the child process to complete. Note that argument processing varies depending on the number of arguments. ! The return value is the exit status of the program. ! See exec. .Ip "tell(FILEHANDLE)" 8 6 .Ip "tell" 8 Returns the current file position for FILEHANDLE. --- 404,413 ---- Does exactly the same thing as \*(L"exec LIST\*(R" except that a fork is done first, and the parent process waits for the child process to complete. Note that argument processing varies depending on the number of arguments. ! The return value is the exit status of the program as returned by the wait() ! call. ! To get the actual exit value divide by 256. ! See also exec. .Ip "tell(FILEHANDLE)" 8 6 .Ip "tell" 8 Returns the current file position for FILEHANDLE.