1 /* $OpenBSD: rcmdsh.c,v 1.5 1998/04/25 16:23:58 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
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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
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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 1.2 2003/06/17 04:26:44 dillon 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(ahost, rport, locuser, remuser, cmd, rshprog)
64 const char *locuser, *remuser, *cmd, *rshprog;
66 struct addrinfo hints, *res;
67 int cpid, sp[2], error;
71 static char hbuf[NI_MAXHOST];
73 /* What rsh/shell to use. */
77 /* locuser must exist on this host. */
78 if ((pw = getpwnam(locuser)) == NULL) {
79 (void)fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
83 /* Validate remote hostname. */
84 if (strcmp(*ahost, "localhost") != 0) {
85 memset(&hints, 0, sizeof(hints));
86 hints.ai_flags = AI_CANONNAME;
87 hints.ai_family = PF_UNSPEC;
88 hints.ai_socktype = SOCK_STREAM;
89 (void)snprintf(num, sizeof(num), "%d", ntohs(rport));
90 error = getaddrinfo(*ahost, num, &hints, &res);
92 fprintf(stderr, "rcmdsh: getaddrinfo: %s\n",
96 if (res->ai_canonname) {
97 strncpy(hbuf, res->ai_canonname, sizeof(hbuf) - 1);
98 hbuf[sizeof(hbuf) - 1] = '\0';
104 /* Get a socketpair we'll use for stdin and stdout. */
105 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sp) == -1) {
106 perror("rcmdsh: socketpair");
112 perror("rcmdsh: fork failed");
114 } else if (cpid == 0) {
116 * Child. We use sp[1] to be stdin/stdout, and close sp[0].
119 if (dup2(sp[1], 0) == -1 || dup2(0, 1) == -1) {
120 perror("rcmdsh: dup2 failed");
123 /* Fork again to lose parent. */
126 perror("rcmdsh: fork to lose parent failed");
132 /* In grandchild here. Become local user for rshprog. */
133 if (setuid(pw->pw_uid) == -1) {
134 (void)fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
135 pw->pw_uid, strerror(errno));
140 * If remote host is "localhost" and local and remote users
141 * are the same, avoid running remote shell for efficiency.
143 if (strcmp(*ahost, "localhost") == 0 &&
144 strcmp(locuser, remuser) == 0) {
145 if (pw->pw_shell[0] == '\0')
146 rshprog = _PATH_BSHELL;
148 rshprog = pw->pw_shell;
149 p = strrchr(rshprog, '/');
150 execlp(rshprog, p ? p + 1 : rshprog, "-c", cmd,
153 p = strrchr(rshprog, '/');
154 execlp(rshprog, p ? p + 1 : rshprog, *ahost, "-l",
155 remuser, cmd, (char *)NULL);
157 (void)fprintf(stderr, "rcmdsh: execlp %s failed: %s\n",
158 rshprog, strerror(errno));
161 /* Parent. close sp[1], return sp[0]. */