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 2021 OmniOS Community Edition (OmniOSce) Association.
26 */
27
28 /*
29 * getcwd() returns the pathname of the current working directory.
30 * On error, a NULL pointer is returned and errno is set.
31 */
32
33 #pragma weak _getcwd = getcwd
34
35 #include "lint.h"
36 #include <sys/param.h>
37 #include <sys/syscall.h>
38 #include <sys/types.h>
39 #include <errno.h>
40 #include <limits.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44
45 char *
getcwd(char * pathname,size_t size)46 getcwd(char *pathname, size_t size)
47 {
48 int alloc = 0;
49
50 if (size == 0 && pathname == NULL) {
51 /*
52 * If no size was provided, start with a buffer that should
53 * accommodate any normal path and, if it is not big enough,
54 * keep doubling it to try and make enough space.
55 *
56 * Any non-global zone path is longer when observed from the
57 * global zone, and some filesystems, including ZFS, support
58 * paths much longer than MAXPATHLEN/_PC_PATH_MAX.
59 *
60 * To protect against unbounded memory usage, cap to 128KiB.
61 * This is an arbitrary limit which is far bigger than the
62 * length of any practical path on the system.
63 */
64 if ((size = pathconf(".", _PC_PATH_MAX)) == -1)
65 size = MAXPATHLEN;
66
67 while (size <= 0x20000) {
68 if ((pathname = reallocf(pathname, size)) == NULL) {
69 errno = ENOMEM;
70 return (NULL);
71 }
72 if (syscall(SYS_getcwd, pathname, size) == 0) {
73 char *ret;
74
75 /*
76 * Shrink the buffer to the length actually
77 * required to hold the final path.
78 */
79 ret = realloc(pathname, strlen(pathname) + 1);
80 if (ret == NULL)
81 return (pathname);
82
83 return (ret);
84 }
85 if (errno != ERANGE)
86 break;
87 size <<= 1;
88 }
89 free(pathname);
90 return (NULL);
91 }
92
93 if (size == 0) {
94 errno = EINVAL;
95 return (NULL);
96 }
97
98 if (pathname == NULL) {
99 if ((pathname = malloc(size)) == NULL) {
100 errno = ENOMEM;
101 return (NULL);
102 }
103 alloc = 1;
104 }
105
106 if (syscall(SYS_getcwd, pathname, size) == 0)
107 return (pathname);
108
109 if (alloc)
110 free(pathname);
111
112 return (NULL);
113 }
114