1 /****************************************************************************
2  * Copyright (c) 1998-2011,2012 Free Software Foundation, Inc.              *
3  *                                                                          *
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5  * copy of this software and associated documentation files (the            *
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9  * copies of the Software, and to permit persons to whom the Software is    *
10  * furnished to do so, subject to the following conditions:                 *
11  *                                                                          *
12  * The above copyright notice and this permission notice shall be included  *
13  * in all copies or substantial portions of the Software.                   *
14  *                                                                          *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
16  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
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21  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
22  *                                                                          *
23  * Except as contained in this notice, the name(s) of the above copyright   *
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27  ****************************************************************************/
28 
29 /****************************************************************************
30  *  Author: Thomas E. Dickey                                                *
31  ****************************************************************************/
32 
33 #include <curses.priv.h>
34 
35 #include <ctype.h>
36 
37 #include <tic.h>
38 
39 MODULE_ID("$Id: access.c,v 1.23 2012/09/01 19:21:29 tom Exp $")
40 
41 #ifdef __TANDEM
42 #define ROOT_UID 65535
43 #endif
44 
45 #ifndef ROOT_UID
46 #define ROOT_UID 0
47 #endif
48 
49 #define LOWERCASE(c) ((isalpha(UChar(c)) && isupper(UChar(c))) ? tolower(UChar(c)) : (c))
50 
51 NCURSES_EXPORT(char *)
52 _nc_rootname(char *path)
53 {
54     char *result = _nc_basename(path);
55 #if !MIXEDCASE_FILENAMES || defined(PROG_EXT)
56     static char *temp;
57     char *s;
58 
59     temp = strdup(result);
60     result = temp;
61 #if !MIXEDCASE_FILENAMES
62     for (s = result; *s != '\0'; ++s) {
63 	*s = (char) LOWERCASE(*s);
64     }
65 #endif
66 #if defined(PROG_EXT)
67     if ((s = strrchr(result, '.')) != 0) {
68 	if (!strcmp(s, PROG_EXT))
69 	    *s = '\0';
70     }
71 #endif
72 #endif
73     return result;
74 }
75 
76 /*
77  * Check if a string appears to be an absolute pathname.
78  */
79 NCURSES_EXPORT(bool)
80 _nc_is_abs_path(const char *path)
81 {
82 #if defined(__EMX__) || defined(__DJGPP__)
83 #define is_pathname(s) ((((s) != 0) && ((s)[0] == '/')) \
84 		  || (((s)[0] != 0) && ((s)[1] == ':')))
85 #else
86 #define is_pathname(s) ((s) != 0 && (s)[0] == '/')
87 #endif
88     return is_pathname(path);
89 }
90 
91 /*
92  * Return index of the basename
93  */
94 NCURSES_EXPORT(unsigned)
95 _nc_pathlast(const char *path)
96 {
97     const char *test = strrchr(path, '/');
98 #ifdef __EMX__
99     if (test == 0)
100 	test = strrchr(path, '\\');
101 #endif
102     if (test == 0)
103 	test = path;
104     else
105 	test++;
106     return (unsigned) (test - path);
107 }
108 
109 NCURSES_EXPORT(char *)
110 _nc_basename(char *path)
111 {
112     return path + _nc_pathlast(path);
113 }
114 
115 NCURSES_EXPORT(int)
116 _nc_access(const char *path, int mode)
117 {
118     int result;
119 
120     if (path == 0) {
121 	result = -1;
122     } else if (access(path, mode) < 0) {
123 	if ((mode & W_OK) != 0
124 	    && errno == ENOENT
125 	    && strlen(path) < PATH_MAX) {
126 	    char head[PATH_MAX];
127 	    char *leaf;
128 
129 	    _nc_STRCPY(head, path, sizeof(head));
130 	    leaf = _nc_basename(head);
131 	    if (leaf == 0)
132 		leaf = head;
133 	    *leaf = '\0';
134 	    if (head == leaf)
135 		_nc_STRCPY(head, ".", sizeof(head));
136 
137 	    result = access(head, R_OK | W_OK | X_OK);
138 	} else {
139 	    result = -1;
140 	}
141     } else {
142 	result = 0;
143     }
144     return result;
145 }
146 
147 NCURSES_EXPORT(bool)
148 _nc_is_dir_path(const char *path)
149 {
150     bool result = FALSE;
151     struct stat sb;
152 
153     if (stat(path, &sb) == 0
154 	&& S_ISDIR(sb.st_mode)) {
155 	result = TRUE;
156     }
157     return result;
158 }
159 
160 NCURSES_EXPORT(bool)
161 _nc_is_file_path(const char *path)
162 {
163     bool result = FALSE;
164     struct stat sb;
165 
166     if (stat(path, &sb) == 0
167 	&& S_ISREG(sb.st_mode)) {
168 	result = TRUE;
169     }
170     return result;
171 }
172 
173 #ifndef USE_ROOT_ENVIRON
174 /*
175  * Returns true if we allow application to use environment variables that are
176  * used for searching lists of directories, etc.
177  */
178 NCURSES_EXPORT(int)
179 _nc_env_access(void)
180 {
181 #if HAVE_ISSETUGID
182     if (issetugid())
183 	return FALSE;
184 #elif HAVE_GETEUID && HAVE_GETEGID
185     if (getuid() != geteuid()
186 	|| getgid() != getegid())
187 	return FALSE;
188 #endif
189     /* ...finally, disallow root */
190     return (getuid() != ROOT_UID) && (geteuid() != ROOT_UID);
191 }
192 #endif
193