xref: /illumos-gate/usr/src/lib/libc/port/gen/execvp.c (revision 6a5408e6)
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 /*
31  *	execlp(name, arg,...,0)	(like execl, but does path search)
32  *	execvp(name, argv)	(like execv, but does path search)
33  */
34 
35 #pragma weak _execlp = execlp
36 #pragma weak _execvp = execvp
37 
38 #include "lint.h"
39 #include <sys/types.h>
40 #include <unistd.h>
41 #include <string.h>
42 #include <alloca.h>
43 #include <errno.h>
44 #include <limits.h>
45 #include <stdarg.h>
46 #include <stdlib.h>
47 #include <paths.h>
48 
49 static const char *execat(const char *, const char *, char *);
50 
51 extern  int __xpg4;	/* defined in xpg4.c; 0 if not xpg4-compiled program */
52 
53 /*VARARGS1*/
54 int
execlp(const char * name,const char * arg0,...)55 execlp(const char *name, const char *arg0, ...)
56 {
57 	char **argp;
58 	va_list args;
59 	char **argvec;
60 	int err;
61 	int nargs = 0;
62 	char *nextarg;
63 
64 	/*
65 	 * count the number of arguments in the variable argument list
66 	 * and allocate an argument vector for them on the stack,
67 	 * adding space for a terminating null pointer at the end
68 	 * and one additional space for argv[0] which is no longer
69 	 * counted by the varargs loop.
70 	 */
71 
72 	va_start(args, arg0);
73 
74 	while (va_arg(args, char *) != (char *)0)
75 		nargs++;
76 
77 	va_end(args);
78 
79 	/*
80 	 * load the arguments in the variable argument list
81 	 * into the argument vector and add the terminating null pointer
82 	 */
83 
84 	va_start(args, arg0);
85 	/* workaround for bugid 1242839 */
86 	argvec = alloca((size_t)((nargs + 2) * sizeof (char *)));
87 	nextarg = va_arg(args, char *);
88 	argp = argvec;
89 	*argp++ = (char *)arg0;
90 	while (nargs-- && nextarg != (char *)0) {
91 		*argp = nextarg;
92 		argp++;
93 		nextarg = va_arg(args, char *);
94 	}
95 	va_end(args);
96 	*argp = (char *)0;
97 
98 	/*
99 	 * call execvp()
100 	 */
101 
102 	err = execvp(name, argvec);
103 	return (err);
104 }
105 
106 int
execvp(const char * name,char * const * argv)107 execvp(const char *name, char *const *argv)
108 {
109 	const char	*pathstr;
110 	char	fname[PATH_MAX+2];
111 	char	*newargs[256];
112 	int	i;
113 	const char *cp;
114 	unsigned etxtbsy = 1;
115 	int eacces = 0;
116 
117 	if (*name == '\0') {
118 		errno = ENOENT;
119 		return (-1);
120 	}
121 	if ((pathstr = getenv("PATH")) == NULL) {
122 		/*
123 		 * XPG4:  pathstr is equivalent to CSPATH, except that
124 		 * :/usr/sbin is appended when root, and pathstr must end
125 		 * with a colon when not root.  Keep these paths in sync
126 		 * with CSPATH in confstr.c.  Note that pathstr must end
127 		 * with a colon when not root so that when name doesn't
128 		 * contain '/', the last call to execat() will result in an
129 		 * attempt to execv name from the current directory.
130 		 */
131 		if (geteuid() == 0 || getuid() == 0) {
132 			if (__xpg4 == 0) {	/* not XPG4 */
133 				pathstr = "/usr/sbin:/usr/ccs/bin:/usr/bin";
134 			} else {		/* XPG4 (CSPATH + /usr/sbin) */
135 				pathstr = "/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:"
136 				    "/opt/SUNWspro/bin:/usr/sbin";
137 			}
138 		} else {
139 			if (__xpg4 == 0) {	/* not XPG4 */
140 				pathstr = "/usr/ccs/bin:/usr/bin:";
141 			} else {		/* XPG4 (CSPATH) */
142 				pathstr = "/usr/xpg4/bin:/usr/ccs/bin:"
143 				    "/usr/bin:/opt/SUNWspro/bin:";
144 			}
145 		}
146 	}
147 	cp = strchr(name, '/')? (const char *)"": pathstr;
148 
149 	do {
150 		cp = execat(cp, name, fname);
151 	retry:
152 		/*
153 		 * 4025035 and 4038378
154 		 * if a filename begins with a "-" prepend "./" so that
155 		 * the shell can't interpret it as an option
156 		 */
157 		if (*fname == '-') {
158 			size_t size = strlen(fname) + 1;
159 			if ((size + 2) > sizeof (fname)) {
160 				errno = E2BIG;
161 				return (-1);
162 			}
163 			(void) memmove(fname + 2, fname, size);
164 			fname[0] = '.';
165 			fname[1] = '/';
166 		}
167 		(void) execv(fname, argv);
168 		switch (errno) {
169 		case ENOEXEC:
170 			newargs[0] = "sh";
171 			newargs[1] = fname;
172 			for (i = 1; (newargs[i + 1] = argv[i]) != NULL; ++i) {
173 				if (i >= 254) {
174 					errno = E2BIG;
175 					return (-1);
176 				}
177 			}
178 			(void) execv(_PATH_BSHELL, newargs);
179 			return (-1);
180 		case ETXTBSY:
181 			if (++etxtbsy > 5)
182 				return (-1);
183 			(void) sleep(etxtbsy);
184 			goto retry;
185 		case EACCES:
186 			++eacces;
187 			break;
188 		case ENOMEM:
189 		case E2BIG:
190 		case EFAULT:
191 			return (-1);
192 		}
193 	} while (cp);
194 	if (eacces)
195 		errno = EACCES;
196 	return (-1);
197 }
198 
199 static const char *
execat(const char * s1,const char * s2,char * si)200 execat(const char *s1, const char *s2, char *si)
201 {
202 	char	*s;
203 	int cnt = PATH_MAX + 1; /* number of characters in s2 */
204 
205 	s = si;
206 	while (*s1 && *s1 != ':') {
207 		if (cnt > 0) {
208 			*s++ = *s1++;
209 			cnt--;
210 		} else
211 			s1++;
212 	}
213 	if (si != s && cnt > 0) {
214 		*s++ = '/';
215 		cnt--;
216 	}
217 	while (*s2 && cnt > 0) {
218 		*s++ = *s2++;
219 		cnt--;
220 	}
221 	*s = '\0';
222 	return (*s1 ? ++s1: 0);
223 }
224