trc: implement and document <>{cmd} notation - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit 38b62735e4e151b626c46dd284d19fb6b0b3f59b
(DIR) parent 7a7e8ed6b227902528cf8a6bc594bee842d0ea90
(HTM) Author: Michael Teichgräber <mt4swm@googlemail.com>
Date: Sun, 13 Sep 2009 18:26:51 -0400
rc: implement and document <>{cmd} notation
http://codereview.appspot.com/105061
Diffstat:
M man/man1/rc.1 | 14 ++++++++++++++
M src/cmd/rc/havefork.c | 64 +++++++++++++++++++++++--------
2 files changed, 61 insertions(+), 17 deletions(-)
---
(DIR) diff --git a/man/man1/rc.1 b/man/man1/rc.1
t@@ -264,6 +264,20 @@ to compare their outputs
cmp <{old} <{new}
.EE
.HP
+.BI <>{ command }
+.br
+The
+.I command
+is executed asynchronously with its standard input and
+output each connected to a pipe. The value of the argument
+is a pair of file names referring to the two other ends
+of the pipes, in the order corresponding to the symbols
+.B <
+and
+.B >
+(first the pipe connected to the command's standard output,
+then the pipe connected to its standard input).
+.HP
.IB argument ^ argument
.br
The
(DIR) diff --git a/src/cmd/rc/havefork.c b/src/cmd/rc/havefork.c
t@@ -177,18 +177,33 @@ Xpipefd(void)
int pc = p->pc, pid;
char name[40];
int pfd[2];
- int sidefd, mainfd;
- if(pipe(pfd)<0){
- Xerror("can't get pipe");
- return;
+ struct { int sidefd, mainfd; } fd[2], *r, *w;
+
+ r = &fd[0];
+ w = &fd[1];
+ switch(p->code[pc].i){
+ case READ:
+ w = nil;
+ break;
+ case WRITE:
+ r = nil;
}
- if(p->code[pc].i==READ){
- sidefd = pfd[PWR];
- mainfd = pfd[PRD];
+
+ if(r){
+ if(pipe(pfd)<0){
+ Xerror("can't get pipe");
+ return;
+ }
+ r->sidefd = pfd[PWR];
+ r->mainfd = pfd[PRD];
}
- else{
- sidefd = pfd[PRD];
- mainfd = pfd[PWR];
+ if(w){
+ if(pipe(pfd)<0){
+ Xerror("can't get pipe");
+ return;
+ }
+ w->sidefd = pfd[PRD];
+ w->mainfd = pfd[PWR];
}
switch(pid = fork()){
case -1:
t@@ -197,17 +212,32 @@ Xpipefd(void)
case 0:
clearwaitpids();
start(p->code, pc+2, runq->local);
- close(mainfd);
- pushredir(ROPEN, sidefd, p->code[pc].i==READ?1:0);
+ if(r){
+ close(r->mainfd);
+ pushredir(ROPEN, r->sidefd, 1);
+ }
+ if(w){
+ close(w->mainfd);
+ pushredir(ROPEN, w->sidefd, 0);
+ }
runq->ret = 0;
break;
default:
addwaitpid(pid);
- close(sidefd);
- pushredir(ROPEN, mainfd, mainfd); /* isn't this a noop? */
- strcpy(name, Fdprefix);
- inttoascii(name+strlen(name), mainfd);
- pushword(name);
+ if(w){
+ close(w->sidefd);
+ pushredir(ROPEN, w->mainfd, w->mainfd); /* so that Xpopredir can close it later */
+ strcpy(name, Fdprefix);
+ inttoascii(name+strlen(name), w->mainfd);
+ pushword(name);
+ }
+ if(r){
+ close(r->sidefd);
+ pushredir(ROPEN, r->mainfd, r->mainfd);
+ strcpy(name, Fdprefix);
+ inttoascii(name+strlen(name), r->mainfd);
+ pushword(name);
+ }
p->pc = p->code[pc+1].i;
break;
}