Date: Tue, 23 Jun 2009 21:50:06 +0000 (UTC) From: Jilles Tjoelker <jilles@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r194774 - head/bin/sh Message-ID: <200906232150.n5NLo6ws091320@svn.freebsd.org>
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Author: jilles Date: Tue Jun 23 21:50:06 2009 New Revision: 194774 URL: http://svn.freebsd.org/changeset/base/194774 Log: Do not fork for a subshell if it is the last thing this shell is doing (EV_EXIT). The fork is still done as normal if any traps are active. In many cases, the fork can be avoided even without this change by using {} instead of (), but in practice many scripts use (), likely because the syntax is simpler. Example: sh -c '(/bin/sleep 10)& sleep 1;ps -p $! -o comm=' Now prints "sleep" instead of "sh". $! is more useful this way. Most shells (dash, bash, pdksh, ksh93, zsh) seem to print "sleep" for this. Example: sh -c '( ( ( (ps jT))))' Now shows no waiting shell processes instead of four. Most shells (dash, bash, pdksh, ksh93, zsh) seem to show zero or one. PR: bin/74404 Approved by: ed (mentor) (implicit) Modified: head/bin/sh/eval.c Modified: head/bin/sh/eval.c ============================================================================== --- head/bin/sh/eval.c Tue Jun 23 21:48:04 2009 (r194773) +++ head/bin/sh/eval.c Tue Jun 23 21:50:06 2009 (r194774) @@ -401,8 +401,8 @@ evalsubshell(union node *n, int flags) int backgnd = (n->type == NBACKGND); expredir(n->nredir.redirect); - jp = makejob(n, 1); - if (forkshell(jp, n, backgnd) == 0) { + if ((!backgnd && flags & EV_EXIT && !have_traps()) || + forkshell(jp = makejob(n, 1), n, backgnd) == 0) { if (backgnd) flags &=~ EV_TESTED; redirect(n->nredir.redirect, 0);
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