x=foo; @{x=bar}; echo `{cat /env/x}
yields "foo" but
x=foo; echo; @{x=bar}; echo `{cat /env/x}
yields "bar"
the problem is that the environment variables are
only flushed to /env on exec, but not on fork.
in the first example, after executing the
subshell, x is still marked as "modified" by
us and the cat/echo will cause the old value
to be flushed and the changed value from the
subshell be overridden.
havntfork.c does flush the variables on fork tho.
i think it would be more consistent todo this for
havefork.c as well.
is there a good reason not to?
the following patch seems to work fine:
diff -r 5a4a76cd3657 sys/src/cmd/rc/havefork.c
--- a/sys/src/cmd/rc/havefork.c Mon Aug 19 16:07:07 2013 +0200
+++ b/sys/src/cmd/rc/havefork.c Mon Aug 19 21:31:06 2013 +0200
@@ -12,10 +12,12 @@
int null = open("/dev/null", 0);
int pid;
char npid[10];
+
if(null<0){
Xerror("Can't open /dev/null\n");
return;
}
+ Updenv();
switch(pid = rfork(RFFDG|RFPROC|RFNOTEG)){
case -1:
close(null);
@@ -45,10 +47,12 @@
int lfd = p->code[pc++].i;
int rfd = p->code[pc++].i;
int pfd[2];
+
if(pipe(pfd)<0){
Xerror("can't get pipe");
return;
}
+ Updenv();
switch(forkid = fork()){
case -1:
Xerror("try again");
@@ -91,6 +95,7 @@
Xerror("can't make pipe");
return;
}
+ Updenv();
switch(pid = fork()){
case -1:
Xerror("try again");
@@ -152,6 +157,7 @@
char name[40];
int pfd[2];
int sidefd, mainfd;
+
if(pipe(pfd)<0){
Xerror("can't get pipe");
return;
@@ -164,6 +170,7 @@
sidefd = pfd[PRD];
mainfd = pfd[PWR];
}
+ Updenv();
switch(pid = fork()){
case -1:
Xerror("try again");
@@ -191,6 +198,8 @@
Xsubshell(void)
{
int pid;
+
+ Updenv();
switch(pid = fork()){
case -1:
Xerror("try again");
--
cinap
