GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/net/rcmdsh.c Lines: 0 89 0.0 %
Date: 2017-11-13 Branches: 0 50 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: rcmdsh.c,v 1.19 2016/05/28 15:46:00 millert Exp $	*/
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/*
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 * Copyright (c) 2001, MagniComp
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in
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 *    the documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the MagniComp nor the names of its contributors may
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 *    be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
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 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/*
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 * This is an rcmd() replacement originally by
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 * Chris Siebenmann <cks@utcc.utoronto.ca>.
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 */
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#include      <sys/types.h>
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#include      <sys/socket.h>
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#include      <sys/wait.h>
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#include      <signal.h>
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#include      <errno.h>
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#include      <limits.h>
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#include      <netdb.h>
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#include      <stdio.h>
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#include      <stdlib.h>
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#include      <string.h>
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#include      <pwd.h>
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#include      <paths.h>
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#include      <unistd.h>
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/*
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 * This is a replacement rcmd() function that uses the ssh(1)
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 * program in place of a direct rcmd(3) function call so as to
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 * avoid having to be root.  Note that rport is ignored.
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 */
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int
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rcmdsh(char **ahost, int rport, const char *locuser, const char *remuser,
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    const char *cmd, char *rshprog)
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{
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	static char hbuf[HOST_NAME_MAX+1];
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	struct addrinfo hint, *res;
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	int sp[2];
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	pid_t cpid;
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	char *p, pwbuf[_PW_BUF_LEN];
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	struct passwd pwstore, *pw = NULL;
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	/* What rsh/shell to use. */
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	if (rshprog == NULL)
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		rshprog = _PATH_RSH;
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	/* locuser must exist on this host. */
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	getpwnam_r(locuser, &pwstore, pwbuf, sizeof(pwbuf), &pw);
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	if (pw == NULL) {
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		(void) fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
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		return(-1);
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	}
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	/* Validate remote hostname. */
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	if (strcmp(*ahost, "localhost") != 0) {
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		memset(&hint, 0, sizeof(hint));
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		hint.ai_family = PF_UNSPEC;
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		hint.ai_flags = AI_CANONNAME;
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		if (getaddrinfo(*ahost, NULL, &hint, &res) == 0) {
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			if (res->ai_canonname) {
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				strlcpy(hbuf, res->ai_canonname, sizeof(hbuf));
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				*ahost = hbuf;
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			}
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			freeaddrinfo(res);
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		}
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	}
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	/* Get a socketpair we'll use for stdin and stdout. */
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	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sp) < 0) {
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		perror("rcmdsh: socketpair");
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		return(-1);
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	}
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	cpid = fork();
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	if (cpid < 0) {
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		perror("rcmdsh: fork failed");
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		return(-1);
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	} else if (cpid == 0) {
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		/*
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		 * Child.  We use sp[1] to be stdin/stdout, and close sp[0].
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		 */
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		(void) close(sp[0]);
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		if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) {
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			perror("rcmdsh: dup2 failed");
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			_exit(255);
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		}
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		/* Fork again to lose parent. */
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		cpid = fork();
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		if (cpid < 0) {
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			perror("rcmdsh: fork to lose parent failed");
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			_exit(255);
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		}
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		if (cpid > 0)
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			_exit(0);
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		/* In grandchild here.  Become local user for rshprog. */
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		if (setuid(pw->pw_uid)) {
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			(void) fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
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				       pw->pw_uid, strerror(errno));
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			_exit(255);
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		}
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		/*
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		 * If remote host is "localhost" and local and remote user
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		 * are the same, avoid running remote shell for efficiency.
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		 */
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		if (!strcmp(*ahost, "localhost") && !strcmp(locuser, remuser)) {
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			char *argv[4];
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			if (pw->pw_shell[0] == '\0')
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				rshprog = _PATH_BSHELL;
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			else
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				rshprog = pw->pw_shell;
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			p = strrchr(rshprog, '/');
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			argv[0] = p ? p + 1 : rshprog;
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			argv[1] = "-c";
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			argv[2] = (char *)cmd;
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			argv[3] = NULL;
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			execvp(rshprog, argv);
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		} else if ((p = strchr(rshprog, ' ')) == NULL) {
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			/* simple case */
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			char *argv[6];
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			p = strrchr(rshprog, '/');
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			argv[0] = p ? p + 1 : rshprog;
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			argv[1] = "-l";
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			argv[2] = (char *)remuser;
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			argv[3] = *ahost;
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			argv[4] = (char *)cmd;
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			argv[5] = NULL;
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			execvp(rshprog, argv);
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		} else {
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			/* must pull args out of rshprog and dyn alloc argv */
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			char **argv, **ap;
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			int n;
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			for (n = 7; (p = strchr(++p, ' ')) != NULL; n++)
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				continue;
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			rshprog = strdup(rshprog);
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			ap = argv = calloc(sizeof(char *), n);
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			if (rshprog == NULL || argv == NULL) {
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				perror("rcmdsh");
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				_exit(255);
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			}
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			while ((p = strsep(&rshprog, " ")) != NULL) {
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				if (*p == '\0')
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					continue;
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				*ap++ = p;
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			}
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			if (ap != argv)		/* all spaces?!? */
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				rshprog = argv[0];
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			if ((p = strrchr(argv[0], '/')) != NULL)
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				argv[0] = p + 1;
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			*ap++ = "-l";
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			*ap++ = (char *)remuser;
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			*ap++ = *ahost;
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			*ap++ = (char *)cmd;
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			*ap++ = NULL;
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			execvp(rshprog, argv);
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		}
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		(void) fprintf(stderr, "rcmdsh: execvp %s failed: %s\n",
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			       rshprog, strerror(errno));
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		_exit(255);
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	} else {
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		/* Parent. close sp[1], return sp[0]. */
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		(void) close(sp[1]);
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		/* Reap child. */
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		while (waitpid(cpid, NULL, 0) == -1 && errno == EINTR)
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			;
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		return(sp[0]);
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	}
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	/* NOTREACHED */
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}
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DEF_WEAK(rcmdsh);