Initial revision

1 files changed, 77 insertions, 0 deletions

diff --git a/redir.c b/redir.c
new file mode 100644
index 0000000..b582341
--- /dev/null
+++ b/redir.c
@@ -0,0 +1,77 @@
+/* redir.c: code for opening files and piping heredocs after fork but before exec. */
+
+#include "rc.h"
+
+/*
+   Walk the redirection queue, and open files and dup2 to them. Also,
+   here-documents are treated here by dumping them down a pipe. (this
+   should make here-documents fast on systems with lots of memory which
+   do pipes right. Under sh, a file is copied to /tmp, and then read
+   out of /tmp again. I'm interested in knowing how much faster, say,
+   shar runs when unpacking when invoked with rc instead of sh. On my
+   sun4/280, it runs in about 60-75% of the time of sh for unpacking
+   the rc source distribution.)
+*/
+
+extern void doredirs() {
+	List *fname;
+	int fd, p[2];
+	Rq *r;
+	for (r = redirq; r != NULL; r = r->n) {
+		switch(r->r->type) {
+		default:
+			panic("unexpected node in doredirs");
+			/* NOTREACHED */
+		case nRedir:
+			if (r->r->u[0].i == rHerestring) {
+				fname = flatten(glom(r->r->u[2].p)); /* fname is really a string */
+				if (pipe(p) < 0) {
+					uerror("pipe");
+					rc_error(NULL);
+				}
+				if (rc_fork() == 0) { /* child writes to pipe */
+					setsigdefaults(FALSE);
+					close(p[0]);
+					if (fname != NULL)
+						writeall(p[1], fname->w, strlen(fname->w));
+					exit(0);
+				} else {
+					close(p[1]);
+					if (mvfd(p[0], r->r->u[1].i) < 0)
+						rc_error(NULL);
+				}
+			} else {
+				fname = glob(glom(r->r->u[2].p));
+				if (fname == NULL)
+					rc_error("null filename in redirection");
+				if (fname->n != NULL)
+					rc_error("multi-word filename in redirection");
+				switch (r->r->u[0].i) {
+				default:
+					panic("unexpected node in doredirs");
+					/* NOTREACHED */
+				case rCreate: case rAppend: case rFrom:
+					fd = rc_open(fname->w, r->r->u[0].i);
+					break;
+				}
+				if (fd < 0) {
+					uerror(fname->w);
+					rc_error(NULL);
+				}
+				if (mvfd(fd, r->r->u[1].i) < 0)
+					rc_error(NULL);
+			}
+			break;
+		case nDup:
+			if (r->r->u[2].i == -1)
+				close(r->r->u[1].i);
+			else if (r->r->u[2].i != r->r->u[1].i) {
+				if (dup2(r->r->u[2].i, r->r->u[1].i) < 0) {
+					uerror("dup2");
+					rc_error(NULL);
+				}
+			}
+		}
+	}
+	redirq = NULL;
+}