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 * 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