1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  * Copyright (c) 2015 Theo de Raadt <deraadt@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <limits.h>
19 #include <stdlib.h>
20 #include <unistd.h>
21 #include <stdio.h>
22 #include <string.h>
23 
24 #include "got_error.h"
25 
26 #include "got_lib_path.h"
27 
28 int
29 got_path_is_absolute(const char *path)
30 {
31 	return path[0] == '/';
32 }
33 
34 char *
35 got_path_get_absolute(const char *relpath) 
36 {
37 	char cwd[PATH_MAX];
38 	char *abspath;
39 
40 	if (getcwd(cwd, sizeof(cwd)) == NULL)
41 		return NULL;
42 
43 	if (asprintf(&abspath, "%s/%s/", cwd, relpath) == -1)
44 		return NULL;
45 
46 	return abspath;
47 }
48 
49 char *
50 got_path_normalize(const char *path)
51 {
52 	char *resolved;
53 
54 	resolved = realpath(path, NULL);
55 	if (resolved == NULL)
56 		return NULL;
57 	
58 	if (!got_path_is_absolute(resolved)) {
59 		char *abspath = got_path_get_absolute(resolved);
60 		free(resolved);
61 		resolved = abspath;
62 	}
63 
64 	return resolved;
65 }
66 
67 /* based on canonpath() from kern_pledge.c */
68 const struct got_error *
69 got_canonpath(const char *input, char *buf, size_t bufsize)
70 {
71 	const char *p;
72 	char *q;
73 
74 	/* can't canon relative paths, don't bother */
75 	if (!got_path_is_absolute(input)) {
76 		if (strlcpy(buf, input, bufsize) >= bufsize)
77 			return got_error(GOT_ERR_NO_SPACE);
78 		return NULL;
79 	}
80 
81 	p = input;
82 	q = buf;
83 	while (*p && (q - buf < bufsize)) {
84 		if (p[0] == '/' && (p[1] == '/' || p[1] == '\0')) {
85 			p += 1;
86 
87 		} else if (p[0] == '/' && p[1] == '.' &&
88 		    (p[2] == '/' || p[2] == '\0')) {
89 			p += 2;
90 
91 		} else if (p[0] == '/' && p[1] == '.' && p[2] == '.' &&
92 		    (p[3] == '/' || p[3] == '\0')) {
93 			p += 3;
94 			if (q != buf)	/* "/../" at start of buf */
95 				while (*--q != '/')
96 					continue;
97 
98 		} else {
99 			*q++ = *p++;
100 		}
101 	}
102 	if ((*p == '\0') && (q - buf < bufsize)) {
103 		*q = 0;
104 		return NULL;
105 	} else
106 		return got_error(GOT_ERR_NO_SPACE);
107 }
108 
109 const struct got_error *
110 got_path_skip_common_ancestor(char **child, const char *parent_abspath,
111     const char *abspath)
112 {
113 	const struct got_error *err = NULL;
114 	size_t len_parent, len, bufsize;
115 
116 	len_parent = strlen(parent_abspath);
117 	len = strlen(abspath);
118 	if (len_parent >= len)
119 		return got_error(GOT_ERR_BAD_PATH);
120 	if (strncmp(parent_abspath, abspath, len_parent) != 0)
121 		return got_error(GOT_ERR_BAD_PATH);
122 	if (abspath[len_parent] != '/')
123 		return got_error(GOT_ERR_BAD_PATH);
124 	bufsize = len - len_parent + 1;
125 	*child = malloc(bufsize);
126 	if (*child == NULL)
127 		return got_error_from_errno();
128 	if (strlcpy(*child, abspath + len_parent, bufsize) >= bufsize) {
129 		err = got_error_from_errno();
130 		free(*child);
131 		*child = NULL;
132 		return err;
133 	}
134 	return NULL;
135 }
136 
137 int
138 got_path_is_root_dir(const char *path)
139 {
140 	return (path[0] == '/' && path[1] == '\0');
141 }