Adds rcmdsh() -- rcmd-alike using rsh (or specified shell).

2 files changed, 122 insertions, 2 deletions

diff --git a/lib/libc/net/Makefile.inc b/lib/libc/net/Makefile.inc
index e71a0f99fe5..708684876ab 100644
--- a/lib/libc/net/Makefile.inc
+++ b/lib/libc/net/Makefile.inc
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile.inc,v 1.6 1996/08/19 08:28:32 tholo Exp $
+#	$OpenBSD: Makefile.inc,v 1.7 1996/08/22 20:11:19 millert Exp $
 
 # net sources
 .PATH: ${.CURDIR}/arch/${MACHINE_ARCH}/net ${.CURDIR}/net
@@ -10,7 +10,7 @@ SRCS+=	gethostnamadr.c getnetbyaddr.c getnetbyname.c getnetent.c \
 	ipx_addr.c ipx_ntoa.c \
 	iso_addr.c linkaddr.c ns_addr.c ns_ntoa.c nsap_addr.c rcmd.c recv.c \
 	res_comp.c res_debug.c res_init.c res_mkquery.c res_query.c \
-	res_send.c send.c sethostent.c ethers.c
+	res_send.c send.c sethostent.c ethers.c rcmdsh.c
 
 # machine-dependent net sources
 # m-d Makefile.inc must include sources for:
diff --git a/lib/libc/net/rcmdsh.c b/lib/libc/net/rcmdsh.c
new file mode 100644
index 00000000000..47b200ed682
--- /dev/null
+++ b/lib/libc/net/rcmdsh.c
@@ -0,0 +1,120 @@
+/*	$OpenBSD: rcmdsh.c,v 1.1 1996/08/22 20:11:20 millert Exp $	*/ 
+
+/*
+ * This is an rcmd() replacement originally by 
+ * Chris Siebenmann <cks@utcc.utoronto.ca>.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char *rcsid = "$OpenBSD: rcmdsh.c,v 1.1 1996/08/22 20:11:20 millert Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+#include      <sys/types.h>
+#include      <sys/socket.h>
+#include      <sys/wait.h>
+#include      <signal.h>
+#include      <errno.h>
+#include      <netdb.h>
+#include      <stdio.h>
+#include      <string.h>
+#include      <pwd.h>
+#include      <paths.h>
+
+/*
+ * This is a replacement rcmd() function that uses the rsh(1)
+ * program in place of a direct rcmd(3) function call so as to
+ * avoid having to be root.  Note that rport is ignored.
+ */
+int
+rcmdsh(ahost, rport, locuser, remuser, cmd, rshprog)
+	char **ahost;
+	u_short	rport;
+	char *locuser, *remuser, *cmd;
+	char *rshprog;
+{
+	struct hostent *hp;
+	int cpid, sp[2];
+	char *p;
+	struct passwd *pw;
+
+	/* What rsh/shell to use. */
+	if (rshprog == NULL)
+		rshprog = _PATH_RSH;
+
+	/* locuser must exist on this host. */
+	if ((pw = getpwnam(locuser)) == NULL) {
+		(void) fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
+		return(-1);
+	}
+
+	/* Validate remote hostname. */
+	if ((hp = gethostbyname(*ahost)) == NULL) {
+		herror(*ahost);
+		return(-1);
+	}
+	*ahost = hp->h_name;
+
+	/* Get a socketpair we'll use for stdin and stdout. */
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) {
+		perror("rcmdsh: socketpair");
+		return(-1);
+	}
+
+	cpid = fork();
+	if (cpid < 0) {
+		perror("rcmdsh: fork failed");
+		return(-1);
+	} else if (cpid == 0) {
+		/*
+		 * Child.  We use sp[1] to be stdin/stdout, and close sp[0].
+		 */
+		(void) close(sp[0]);
+		if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0 || dup2(0, 2) < 0) {
+			perror("rcmdsh: dup2 failed");
+			_exit(255);
+		}
+		/* Fork again to lose parent. */
+		cpid = fork();
+		if (cpid < 0) {
+			perror("rcmdsh: fork to lose parent failed");
+			_exit(255);
+		}
+		if (cpid > 0)
+			_exit(0);
+
+		/* In grandchild here.  Become local user for rshprog. */
+		if (setuid(pw->pw_uid)) {
+			(void) fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
+				       pw->pw_uid, strerror(errno));
+			_exit(255);
+		}
+
+		/*
+		 * If remote host is "localhost" and local and remote user
+		 * are the same, avoid running remote shell for efficiency.
+		 */
+		if (!strcmp(*ahost, "localhost") && !strcmp(locuser, remuser)) {
+			if (pw->pw_shell[0] == '\0')
+				rshprog = _PATH_BSHELL;
+			else
+				rshprog = pw->pw_shell;
+			p = strrchr(rshprog, '/');
+			execlp(rshprog, p ? p+1 : rshprog, "-c", cmd,
+			       (char *) NULL);
+		} else {
+			p = strrchr(rshprog, '/');
+			execlp(rshprog, p ? p+1 : rshprog, *ahost, "-l",
+			       remuser, cmd, (char *) NULL);
+		}
+		(void) fprintf(stderr, "rcmdsh: execlp %s failed: %s\n",
+			       rshprog, strerror(errno));
+		_exit(255);
+	} else if (cpid > 0) {
+		/* Parent. close sp[1], return sp[0]. */
+		(void) close(sp[1]);
+		/* Reap child. */
+		(void) wait(NULL);
+		return(sp[0]);
+	}
+	/*NOTREACHED*/
+}