Annotation of src/usr.bin/rdist/rshrcmd.c, Revision 1.6
1.6 ! millert 1: /* $OpenBSD: rshrcmd.c,v 1.5 1996/09/07 03:14:27 millert Exp $ */
1.3 deraadt 2:
1.1 dm 3:
4: /*
5: * This is an rcmd() replacement originally by
6: * Chris Siebenmann <cks@utcc.utoronto.ca>.
7: */
8:
9: #ifndef lint
10: static char RCSid[] =
1.6 ! millert 11: "$OpenBSD: rshrcmd.c,v 1.5 1996/09/07 03:14:27 millert Exp $";
1.1 dm 12: #endif
13:
1.5 millert 14: #include "defs.h"
1.1 dm 15:
16: #if !defined(DIRECT_RCMD)
17:
18: #include <sys/types.h>
19: #include <sys/socket.h>
20: #include <sys/wait.h>
21: #include <signal.h>
22: #include <errno.h>
23: #include <netdb.h>
24: #include <stdio.h>
25:
26: /*
27: * This is a replacement rcmd() function that uses the rsh(1c)
28: * program in place of a direct rcmd() function call so as to
29: * avoid having to be root.
30: */
31: rshrcmd(ahost, port, luser, ruser, cmd, fd2p)
32: char **ahost;
33: u_short port;
34: char *luser, *ruser, *cmd;
35: int *fd2p;
36: {
37: int cpid;
38: struct hostent *hp;
39: int sp[2];
40:
41: /* insure that we are indeed being used as we thought. */
42: if (fd2p != 0)
43: return -1;
44: /* validate remote hostname. */
45: hp = gethostbyname(*ahost);
46: if (hp == 0) {
47: error("%s: unknown host", *ahost);
48: return -1;
49: }
50: /* *ahost = hp->h_name; /* This makes me nervous. */
51:
52: /* get a socketpair we'll use for stdin and stdout. */
53: if (getsocketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) {
54: error("socketpair(AF_UNIX, SOCK_STREAM, 0) failed: %s.",
55: SYSERR);
56: return -1;
57: }
58:
59: cpid = fork();
60: if (cpid < 0) {
61: error("fork failed: %s.", SYSERR);
62: return -1; /* error. */
63: }
64: if (cpid == 0) {
65: /* child. we use sp[1] to be stdin/stdout, and close
66: sp[0]. */
67: (void) close(sp[0]);
1.6 ! millert 68: if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) {
1.1 dm 69: error("dup2 failed: %s.", SYSERR);
70: _exit(255);
71: }
72: /* fork again to lose parent. */
73: cpid = fork();
74: if (cpid < 0) {
75: error("fork to lose parent failed: %s.", SYSERR);
76: _exit(255);
77: }
78: if (cpid > 0)
79: _exit(0);
80: /* in grandchild here. */
81:
82: /*
83: * If we are rdist'ing to "localhost" as the same user
84: * as we are, then avoid running remote shell for efficiency.
85: */
86: if (strcmp(*ahost, "localhost") == 0 &&
87: strcmp(luser, ruser) == 0) {
88: execlp(_PATH_BSHELL, xbasename(_PATH_BSHELL), "-c",
89: cmd, (char *) NULL);
90: error("execlp %s failed: %s.", _PATH_BSHELL, SYSERR);
91: } else {
92: execlp(path_remsh, xbasename(path_remsh),
93: *ahost, "-l", ruser, cmd, (char *) NULL);
94: error("execlp %s failed: %s.", path_remsh, SYSERR);
95: }
96: _exit(255);
97: }
98: if (cpid > 0) {
99: /* parent. close sp[1], return sp[0]. */
100: (void) close(sp[1]);
101: /* reap child. */
102: (void) wait(0);
103: return sp[0];
104: }
105: /*NOTREACHED*/
106: }
107:
108: #endif /* !DIRECT_RCMD */