diff options
Diffstat (limited to 'usr/src/cmd/csh/sh.proc.c')
| -rw-r--r-- | usr/src/cmd/csh/sh.proc.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/usr/src/cmd/csh/sh.proc.c b/usr/src/cmd/csh/sh.proc.c index 195d2b07a1..2e4bfc4ea9 100644 --- a/usr/src/cmd/csh/sh.proc.c +++ b/usr/src/cmd/csh/sh.proc.c @@ -1,5 +1,5 @@ /* - * Copyright 2004 Sun Microsystems, Inc. All rights reserved. + * Copyright 2005 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ @@ -230,7 +230,29 @@ pjwait(pp) while ((fp = (fp->p_friends)) != pp); if ((jobflags & PRUNNING) == 0) break; - sigpause(sigblock(0) &~ sigmask(SIGCHLD)); + /* + * At this point, csh used to call: + * sigpause(sigblock(0) &~ sigmask(SIGCHLD)); + * expecting to receive a SIGCHLD signal from the + * termination of the child and to invoke the + * signal handler, pchild(), as a result. + * + * However, vfork() now causes a vfork()'d child to + * have all of its active signal handlers reset to + * SIG_DFL, to forstall parent memory corruption due + * to race conditions with signal handling. + * + * If this instance of csh is itself a child of vfork(), + * which can happen when the top-level csh performs a + * command substitution inside an i/o redirection, like: + * /bin/echo foo >`/bin/echo trash` + * then we will never receive SIGCHLD. To accommodate + * this, we wait until one of our children terminates + * (without actually reaping the child) and call the + * SIGCHLD signal handler (pchild()) directly. + */ + if (csh_wait_noreap() > 0) + pchild(); /* simulate receipt of SIGCHLD */ } (void) sigsetmask(omask); if (tpgrp > 0) /* get tty back */ |