ttry harder to put background jobs in background; do not print in response to SIGPIPE - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit 4ee543e58c5e6cf5ef0b94dfec752dadbbd063d3
(DIR) parent ca30274bd90f09b6d19d36b87278fdb40efddada
(HTM) Author: rsc <devnull@localhost>
Date: Fri, 18 Mar 2005 19:03:25 +0000
ttry harder to put background jobs in background; do not print in response to SIGPIPE
Diffstat:
M src/cmd/rc/exec.c | 32 ++++++++++++++++++++++++++++++-
M src/cmd/rc/havefork.c | 10 ++++++++++
M src/cmd/rc/plan9ish.c | 1 +
M src/cmd/rc/rc.h | 3 +++
4 files changed, 45 insertions(+), 1 deletion(-)
---
(DIR) diff --git a/src/cmd/rc/exec.c b/src/cmd/rc/exec.c
t@@ -1,3 +1,6 @@
+#include <u.h>
+#include <signal.h>
+#include <sys/ioctl.h>
#include "rc.h"
#include "getflags.h"
#include "exec.h"
t@@ -220,6 +223,7 @@ void Xappend(void){
}
void Xasync(void){
int null=open("/dev/null", 0);
+ int tty;
int pid;
char npid[10];
if(null<0){
t@@ -232,7 +236,33 @@ void Xasync(void){
Xerror("try again");
break;
case 0:
- pushredir(ROPEN, null, 0);
+ /*
+ * I don't know what the right thing to do here is,
+ * so this is all experimentally determined.
+ * If we just dup /dev/null onto 0, then running
+ * ssh foo & will reopen /dev/tty, try to read a password,
+ * get a signal, and repeat, in a tight loop, forever.
+ * Arguably this is a bug in ssh (it behaves the same
+ * way under bash as under rc) but I'm fixing it here
+ * anyway. If we dissociate the process from the tty,
+ * then it won't be able to open /dev/tty ever again.
+ * The SIG_IGN on SIGTTOU makes writing the tty
+ * (via fd 1 or 2, for example) succeed even though
+ * our pgrp is not the terminal's controlling pgrp.
+ */
+ if((tty=open("/dev/tty", OREAD)) >= 0){
+ /*
+ * Should make reads of tty fail, writes succeed.
+ */
+ signal(SIGTTIN, SIG_IGN);
+ signal(SIGTTOU, SIG_IGN);
+ ioctl(tty, TIOCNOTTY);
+ close(tty);
+ }
+ if(isatty(0))
+ pushredir(ROPEN, null, 0);
+ else
+ close(null);
start(runq->code, runq->pc+1, runq->local);
runq->ret=0;
break;
(DIR) diff --git a/src/cmd/rc/havefork.c b/src/cmd/rc/havefork.c
t@@ -1,3 +1,5 @@
+#include <u.h>
+#include <signal.h>
#include "rc.h"
#include "getflags.h"
#include "exec.h"
t@@ -11,7 +13,9 @@ Xasync(void)
{
int null = open("/dev/null", 0);
int pid;
+ int tcpgrp, pgrp;
char npid[10];
+
if(null<0){
Xerror("Can't open /dev/null\n");
return;
t@@ -22,6 +26,12 @@ Xasync(void)
Xerror("try again");
break;
case 0:
+ /*
+ * Should make reads of tty fail, writes succeed.
+ */
+ signal(SIGTTIN, SIG_IGN);
+ signal(SIGTTOU, SIG_IGN);
+
pushredir(ROPEN, null, 0);
start(runq->code, runq->pc+1, runq->local);
runq->ret = 0;
(DIR) diff --git a/src/cmd/rc/plan9ish.c b/src/cmd/rc/plan9ish.c
t@@ -403,6 +403,7 @@ notifyf(void *unused0, char *s)
}
goto Out;
}
+ if(strcmp(s, "sys: write on closed pipe") != 0)
if(strcmp(s, "sys: child") != 0)
pfmt(err, "rc: note: %s\n", s);
noted(NDFLT);
(DIR) diff --git a/src/cmd/rc/rc.h b/src/cmd/rc/rc.h
t@@ -9,6 +9,9 @@
#ifdef Plan9
#include <u.h>
#include <libc.h>
+#undef NSIG
+#undef SIGINT
+#undef SIGQUIT
#define NSIG 32
#define SIGINT 2
#define SIGQUIT 3