Implement esyscmd

1 files changed, 54 insertions, 1 deletions

diff --git a/usr.bin/m4/gnum4.c b/usr.bin/m4/gnum4.c
index 9fd15a7dc2b..d1efae77903 100644
--- a/usr.bin/m4/gnum4.c
+++ b/usr.bin/m4/gnum4.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: gnum4.c,v 1.7 2000/06/28 10:01:27 espie Exp $ */
+/* $OpenBSD: gnum4.c,v 1.8 2000/07/24 23:08:25 espie Exp $ */
 
 /*
  * Copyright (c) 1999 Marc Espie
@@ -31,13 +31,17 @@
 
 #include <sys/param.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <ctype.h>
+#include <paths.h>
 #include <regex.h>
 #include <stddef.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <err.h>
+#include <errno.h>
+#include <unistd.h>
 #include "mdef.h"
 #include "stdd.h"
 #include "extern.h"
@@ -478,3 +482,52 @@ doregexp(argv, argc)
 	free(pmatch);
 	regfree(&re);
 }
+
+void
+doesyscmd(cmd)
+	const char *cmd;
+{
+	int p[2];
+	pid_t pid, cpid;
+	char *argv[4];
+	int cc;
+	int status;
+
+	/* Follow gnu m4 documentation: first flush buffers. */
+	fflush(NULL);
+
+	argv[0] = "sh";
+	argv[1] = "-c";
+	argv[2] = (char *)cmd;
+	argv[3] = NULL;
+
+	/* Just set up standard output, share stderr and stdin with m4 */
+	if (pipe(p) == -1)
+		err(1, "bad pipe");
+	switch(cpid = fork()) {
+	case -1:
+		err(1, "bad fork");
+		/* NOTREACHED */
+	case 0:
+		(void) close(p[0]);
+		(void) dup2(p[1], 1);
+		(void) close(p[1]);
+		execv(_PATH_BSHELL, argv);
+		exit(1);
+	default:
+		/* Read result in two stages, since m4's buffer is
+		 * pushback-only. */
+		(void) close(p[1]);
+		do {
+			char result[BUFSIZE];
+			cc = read(p[0], result, sizeof result);
+			if (cc > 0)
+				addchars(result, cc);
+		} while (cc > 0 || (cc == -1 && errno == EINTR));
+
+		(void) close(p[0]);
+		while ((pid = wait(&status)) != cpid && pid >= 0)
+			continue;
+		pbstr(getstring());
+	}
+}