From a48b462e4464c762fac0c8fa0af18d05db2a725f Mon Sep 17 00:00:00 2001 From: cinap_lenrek Date: Sat, 30 May 2020 02:03:18 +0200 Subject: [PATCH] rc: avoid forking for final command that has variable assignments (to get $apid right) basically, we want the following commands to print the same pid twice: rc -c 'cat /dev/pid &;echo $apid' vs: rc -c 'a=1 cat /dev/pid &;echo $apid' basically, Xsimple() calls exitnext() to determine if a simple command should be promoted to exec, by peeking ahead into the code and searching for Xexit instruction. Xexit might not follow immediately after the Xsimple instruction because of redirections, which exitnext() would skip. but it would not skip the Xunlocal instructions that where added by the variable assignment. --- sys/src/cmd/rc/simple.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/src/cmd/rc/simple.c b/sys/src/cmd/rc/simple.c index 982b73cda..8971f201f 100644 --- a/sys/src/cmd/rc/simple.c +++ b/sys/src/cmd/rc/simple.c @@ -12,7 +12,7 @@ int exitnext(void){ union code *c=&runq->code[runq->pc]; - while(c->f==Xpopredir) c++; + while(c->f==Xpopredir || c->f==Xunlocal) c++; return c->f==Xexit; }