xref: /titanic_41/usr/src/lib/libc/port/gen/execvp.c (revision 52ccf843e173e2a4a657360b0a22853fd413905f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 /*
33  *	execlp(name, arg,...,0)	(like execl, but does path search)
34  *	execvp(name, argv)	(like execv, but does path search)
35  */
36 
37 #pragma weak _execlp = execlp
38 #pragma weak _execvp = execvp
39 
40 #include "lint.h"
41 #include <sys/types.h>
42 #include <unistd.h>
43 #include <string.h>
44 #include <alloca.h>
45 #include <errno.h>
46 #include <limits.h>
47 #include <stdarg.h>
48 #include <stdlib.h>
49 
50 static const char *execat(const char *, const char *, char *);
51 
52 extern  int __xpg4;	/* defined in xpg4.c; 0 if not xpg4-compiled program */
53 
54 /*VARARGS1*/
55 int
56 execlp(const char *name, const char *arg0, ...)
57 {
58 	char **argp;
59 	va_list args;
60 	char **argvec;
61 	int err;
62 	int nargs = 0;
63 	char *nextarg;
64 
65 	/*
66 	 * count the number of arguments in the variable argument list
67 	 * and allocate an argument vector for them on the stack,
68 	 * adding space for a terminating null pointer at the end
69 	 * and one additional space for argv[0] which is no longer
70 	 * counted by the varargs loop.
71 	 */
72 
73 	va_start(args, arg0);
74 
75 	while (va_arg(args, char *) != (char *)0)
76 		nargs++;
77 
78 	va_end(args);
79 
80 	/*
81 	 * load the arguments in the variable argument list
82 	 * into the argument vector and add the terminating null pointer
83 	 */
84 
85 	va_start(args, arg0);
86 	/* workaround for bugid 1242839 */
87 	argvec = alloca((size_t)((nargs + 2) * sizeof (char *)));
88 	nextarg = va_arg(args, char *);
89 	argp = argvec;
90 	*argp++ = (char *)arg0;
91 	while (nargs-- && nextarg != (char *)0) {
92 		*argp = nextarg;
93 		argp++;
94 		nextarg = va_arg(args, char *);
95 	}
96 	va_end(args);
97 	*argp = (char *)0;
98 
99 	/*
100 	 * call execvp()
101 	 */
102 
103 	err = execvp(name, argvec);
104 	return (err);
105 }
106 
107 int
108 execvp(const char *name, char *const *argv)
109 {
110 	const char	*pathstr;
111 	char	fname[PATH_MAX+2];
112 	char	*newargs[256];
113 	int	i;
114 	const char *cp;
115 	unsigned etxtbsy = 1;
116 	int eacces = 0;
117 	char *shpath;
118 	static const char *sun_path = "/bin/sh";
119 	static const char *xpg4_path = "/usr/xpg4/bin/sh";
120 	static const char *shell = "sh";
121 
122 	if (*name == '\0') {
123 		errno = ENOENT;
124 		return (-1);
125 	}
126 	if ((pathstr = getenv("PATH")) == NULL) {
127 		/*
128 		 * XPG4:  pathstr is equivalent to CSPATH, except that
129 		 * :/usr/sbin is appended when root, and pathstr must end
130 		 * with a colon when not root.  Keep these paths in sync
131 		 * with CSPATH in confstr.c.  Note that pathstr must end
132 		 * with a colon when not root so that when name doesn't
133 		 * contain '/', the last call to execat() will result in an
134 		 * attempt to execv name from the current directory.
135 		 */
136 		if (geteuid() == 0 || getuid() == 0) {
137 			if (__xpg4 == 0) {	/* not XPG4 */
138 				pathstr = "/usr/sbin:/usr/ccs/bin:/usr/bin";
139 			} else {		/* XPG4 (CSPATH + /usr/sbin) */
140 		pathstr = "/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:"
141 		    "/opt/SUNWspro/bin:/usr/sbin";
142 			}
143 		} else {
144 			if (__xpg4 == 0) {	/* not XPG4 */
145 				pathstr = "/usr/ccs/bin:/usr/bin:";
146 			} else {		/* XPG4 (CSPATH) */
147 				pathstr = "/usr/xpg4/bin:/usr/ccs/bin:"
148 				    "/usr/bin:/opt/SUNWspro/bin:";
149 			}
150 		}
151 	}
152 	cp = strchr(name, '/')? (const char *)"": pathstr;
153 
154 	do {
155 		cp = execat(cp, name, fname);
156 	retry:
157 		/*
158 		 * 4025035 and 4038378
159 		 * if a filename begins with a "-" prepend "./" so that
160 		 * the shell can't interpret it as an option
161 		 */
162 		if (*fname == '-') {
163 			size_t size = strlen(fname) + 1;
164 			if ((size + 2) > sizeof (fname)) {
165 				errno = E2BIG;
166 				return (-1);
167 			}
168 			(void) memmove(fname + 2, fname, size);
169 			fname[0] = '.';
170 			fname[1] = '/';
171 		}
172 		(void) execv(fname, argv);
173 		switch (errno) {
174 		case ENOEXEC:
175 			if (__xpg4 == 0) {	/* not XPG4 */
176 				shpath = (char *)sun_path;
177 			} else {		/* XPG4 */
178 				shpath = (char *)xpg4_path;
179 			}
180 			newargs[0] = (char *)shell;
181 			newargs[1] = fname;
182 			for (i = 1; (newargs[i + 1] = argv[i]) != NULL; ++i) {
183 				if (i >= 254) {
184 					errno = E2BIG;
185 					return (-1);
186 				}
187 			}
188 			(void) execv((const char *)shpath, newargs);
189 			return (-1);
190 		case ETXTBSY:
191 			if (++etxtbsy > 5)
192 				return (-1);
193 			(void) sleep(etxtbsy);
194 			goto retry;
195 		case EACCES:
196 			++eacces;
197 			break;
198 		case ENOMEM:
199 		case E2BIG:
200 		case EFAULT:
201 			return (-1);
202 		}
203 	} while (cp);
204 	if (eacces)
205 		errno = EACCES;
206 	return (-1);
207 }
208 
209 static const char *
210 execat(const char *s1, const char *s2, char *si)
211 {
212 	char	*s;
213 	int cnt = PATH_MAX + 1; /* number of characters in s2 */
214 
215 	s = si;
216 	while (*s1 && *s1 != ':') {
217 		if (cnt > 0) {
218 			*s++ = *s1++;
219 			cnt--;
220 		} else
221 			s1++;
222 	}
223 	if (si != s && cnt > 0) {
224 		*s++ = '/';
225 		cnt--;
226 	}
227 	while (*s2 && cnt > 0) {
228 		*s++ = *s2++;
229 		cnt--;
230 	}
231 	*s = '\0';
232 	return (*s1 ? ++s1: 0);
233 }
234