xref: /illumos-gate/usr/src/lib/libc/port/gen/execvp.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
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  * Copyright 2024 Oxide Computer Company
26  */
27 
28 /*	Copyright (c) 1988 AT&T	*/
29 /*	  All Rights Reserved	*/
30 
31 /*
32  *	execlp(name, arg,...,0)	(like execl, but does path search)
33  *	execvp(name, argv)	(like execv, but does path search)
34  *	execvpe(name, argv, envp) (like execve, 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 #include <paths.h>
50 
51 static const char *execat(const char *, const char *, char *);
52 
53 extern  int __xpg4;	/* defined in xpg4.c; 0 if not xpg4-compiled program */
54 
55 /*VARARGS1*/
56 int
57 execlp(const char *name, const char *arg0, ...)
58 {
59 	char **argp;
60 	va_list args;
61 	char **argvec;
62 	int err;
63 	int nargs = 0;
64 	char *nextarg;
65 
66 	/*
67 	 * count the number of arguments in the variable argument list
68 	 * and allocate an argument vector for them on the stack,
69 	 * adding space for a terminating null pointer at the end
70 	 * and one additional space for argv[0] which is no longer
71 	 * counted by the varargs loop.
72 	 */
73 
74 	va_start(args, arg0);
75 
76 	while (va_arg(args, char *) != (char *)0)
77 		nargs++;
78 
79 	va_end(args);
80 
81 	/*
82 	 * load the arguments in the variable argument list
83 	 * into the argument vector and add the terminating null pointer
84 	 */
85 
86 	va_start(args, arg0);
87 	/* workaround for bugid 1242839 */
88 	argvec = alloca((size_t)((nargs + 2) * sizeof (char *)));
89 	nextarg = va_arg(args, char *);
90 	argp = argvec;
91 	*argp++ = (char *)arg0;
92 	while (nargs-- && nextarg != (char *)0) {
93 		*argp = nextarg;
94 		argp++;
95 		nextarg = va_arg(args, char *);
96 	}
97 	va_end(args);
98 	*argp = (char *)0;
99 
100 	/*
101 	 * call execvp()
102 	 */
103 
104 	err = execvp(name, argvec);
105 	return (err);
106 }
107 
108 static int
109 execvpe_int(const char *name, char *const *argv, char *const *envp,
110     boolean_t use_env)
111 {
112 	const char	*pathstr;
113 	char	fname[PATH_MAX+2];
114 	char	*newargs[256];
115 	int	i;
116 	const char *cp;
117 	unsigned etxtbsy = 1;
118 	int eacces = 0;
119 
120 	if (*name == '\0') {
121 		errno = ENOENT;
122 		return (-1);
123 	}
124 	if ((pathstr = getenv("PATH")) == NULL) {
125 		/*
126 		 * XPG4:  pathstr is equivalent to CSPATH, except that
127 		 * :/usr/sbin is appended when root, and pathstr must end
128 		 * with a colon when not root.  Keep these paths in sync
129 		 * with CSPATH in confstr.c.  Note that pathstr must end
130 		 * with a colon when not root so that when name doesn't
131 		 * contain '/', the last call to execat() will result in an
132 		 * attempt to execv name from the current directory.
133 		 */
134 		if (geteuid() == 0 || getuid() == 0) {
135 			if (__xpg4 == 0) {	/* not XPG4 */
136 				pathstr = "/usr/sbin:/usr/ccs/bin:/usr/bin";
137 			} else {		/* XPG4 (CSPATH + /usr/sbin) */
138 				pathstr = "/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:"
139 				    "/opt/SUNWspro/bin:/usr/sbin";
140 			}
141 		} else {
142 			if (__xpg4 == 0) {	/* not XPG4 */
143 				pathstr = "/usr/ccs/bin:/usr/bin:";
144 			} else {		/* XPG4 (CSPATH) */
145 				pathstr = "/usr/xpg4/bin:/usr/ccs/bin:"
146 				    "/usr/bin:/opt/SUNWspro/bin:";
147 			}
148 		}
149 	}
150 	cp = strchr(name, '/')? (const char *)"": pathstr;
151 
152 	do {
153 		cp = execat(cp, name, fname);
154 	retry:
155 		/*
156 		 * 4025035 and 4038378
157 		 * if a filename begins with a "-" prepend "./" so that
158 		 * the shell can't interpret it as an option
159 		 */
160 		if (*fname == '-') {
161 			size_t size = strlen(fname) + 1;
162 			if ((size + 2) > sizeof (fname)) {
163 				errno = E2BIG;
164 				return (-1);
165 			}
166 			(void) memmove(fname + 2, fname, size);
167 			fname[0] = '.';
168 			fname[1] = '/';
169 		}
170 		if (use_env) {
171 			(void) execve(fname, argv, envp);
172 		} else {
173 			(void) execv(fname, argv);
174 		}
175 		switch (errno) {
176 		case ENOEXEC:
177 			newargs[0] = "sh";
178 			newargs[1] = fname;
179 			for (i = 1; (newargs[i + 1] = argv[i]) != NULL; ++i) {
180 				if (i >= 254) {
181 					errno = E2BIG;
182 					return (-1);
183 				}
184 			}
185 			if (use_env) {
186 				(void) execve(_PATH_BSHELL, newargs, envp);
187 			} else {
188 				(void) execv(_PATH_BSHELL, newargs);
189 			}
190 			return (-1);
191 		case ETXTBSY:
192 			if (++etxtbsy > 5)
193 				return (-1);
194 			(void) sleep(etxtbsy);
195 			goto retry;
196 		case EACCES:
197 			++eacces;
198 			break;
199 		case ENOMEM:
200 		case E2BIG:
201 		case EFAULT:
202 			return (-1);
203 		}
204 	} while (cp);
205 	if (eacces)
206 		errno = EACCES;
207 	return (-1);
208 }
209 
210 int
211 execvp(const char *file, char *const *argv)
212 {
213 	return (execvpe_int(file, argv, NULL, B_FALSE));
214 }
215 
216 int
217 execvpe(const char *file, char *const *argv, char *const *envp)
218 {
219 	return (execvpe_int(file, argv, envp, B_TRUE));
220 }
221 
222 static const char *
223 execat(const char *s1, const char *s2, char *si)
224 {
225 	char	*s;
226 	int cnt = PATH_MAX + 1; /* number of characters in s2 */
227 
228 	s = si;
229 	while (*s1 && *s1 != ':') {
230 		if (cnt > 0) {
231 			*s++ = *s1++;
232 			cnt--;
233 		} else
234 			s1++;
235 	}
236 	if (si != s && cnt > 0) {
237 		*s++ = '/';
238 		cnt--;
239 	}
240 	while (*s2 && cnt > 0) {
241 		*s++ = *s2++;
242 		cnt--;
243 	}
244 	*s = '\0';
245 	return (*s1 ? ++s1: 0);
246 }
247