1 /* $OpenBSD: rcmdsh.c,v 1.7 2002/03/12 00:05:44 millert Exp $ */
4 * Copyright (c) 2001, MagniComp
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the MagniComp nor the names of its contributors may
16 * be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
26 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
28 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 * $FreeBSD: src/lib/libc/net/rcmdsh.c,v 1.3.2.2 2002/04/22 17:38:53 ume Exp $
31 * $DragonFly: src/lib/libc/net/rcmdsh.c,v 1.4 2005/11/13 02:04:47 swildner Exp $
35 * This is an rcmd() replacement originally by
36 * Chris Siebenmann <cks@utcc.utoronto.ca>.
39 #include <sys/types.h>
40 #include <sys/socket.h>
52 #define _PATH_RSH "/usr/bin/rsh"
56 * This is a replacement rcmd() function that uses the rsh(1)
57 * program in place of a direct rcmd(3) function call so as to
58 * avoid having to be root. Note that rport is ignored.
61 rcmdsh(char **ahost
, int rport
, const char *locuser
, const char *remuser
,
62 const char *cmd
, const char *rshprog
)
64 struct addrinfo hints
, *res
;
70 static char hbuf
[NI_MAXHOST
];
72 /* What rsh/shell to use. */
76 /* locuser must exist on this host. */
77 if ((pw
= getpwnam(locuser
)) == NULL
) {
78 fprintf(stderr
, "rcmdsh: unknown user: %s\n", locuser
);
82 /* Validate remote hostname. */
83 if (strcmp(*ahost
, "localhost") != 0) {
84 memset(&hints
, 0, sizeof(hints
));
85 hints
.ai_flags
= AI_CANONNAME
;
86 hints
.ai_family
= PF_UNSPEC
;
87 hints
.ai_socktype
= SOCK_STREAM
;
88 snprintf(num
, sizeof(num
), "%d", ntohs(rport
));
89 error
= getaddrinfo(*ahost
, num
, &hints
, &res
);
91 fprintf(stderr
, "rcmdsh: getaddrinfo: %s\n",
95 if (res
->ai_canonname
) {
96 strncpy(hbuf
, res
->ai_canonname
, sizeof(hbuf
) - 1);
97 hbuf
[sizeof(hbuf
) - 1] = '\0';
103 /* Get a socketpair we'll use for stdin and stdout. */
104 if (socketpair(AF_UNIX
, SOCK_STREAM
, PF_UNSPEC
, sp
) == -1) {
105 perror("rcmdsh: socketpair");
111 perror("rcmdsh: fork failed");
113 } else if (cpid
== 0) {
115 * Child. We use sp[1] to be stdin/stdout, and close sp[0].
118 if (dup2(sp
[1], 0) == -1 || dup2(0, 1) == -1) {
119 perror("rcmdsh: dup2 failed");
122 /* Fork again to lose parent. */
125 perror("rcmdsh: fork to lose parent failed");
131 /* In grandchild here. Become local user for rshprog. */
132 if (setuid(pw
->pw_uid
) == -1) {
133 fprintf(stderr
, "rcmdsh: setuid(%u): %s\n",
134 pw
->pw_uid
, strerror(errno
));
139 * If remote host is "localhost" and local and remote users
140 * are the same, avoid running remote shell for efficiency.
142 if (strcmp(*ahost
, "localhost") == 0 &&
143 strcmp(locuser
, remuser
) == 0) {
144 if (pw
->pw_shell
[0] == '\0')
145 rshprog
= _PATH_BSHELL
;
147 rshprog
= pw
->pw_shell
;
148 p
= strrchr(rshprog
, '/');
149 execlp(rshprog
, p
? p
+ 1 : rshprog
, "-c", cmd
,
152 p
= strrchr(rshprog
, '/');
153 execlp(rshprog
, p
? p
+ 1 : rshprog
, *ahost
, "-l",
154 remuser
, cmd
, (char *)NULL
);
156 fprintf(stderr
, "rcmdsh: execlp %s failed: %s\n",
157 rshprog
, strerror(errno
));
160 /* Parent. close sp[1], return sp[0]. */