1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /* Utilities for dealing with filesystem paths. */
18 
19 #define GOT_DEFAULT_FILE_MODE	(S_IFREG | \
20 	S_IRUSR|S_IWUSR | S_IRGRP | S_IROTH)
21 #define GOT_DEFAULT_DIR_MODE	(S_IFDIR | \
22 	S_IRWXU | S_IRGRP|S_IXGRP | S_IROTH|S_IXOTH)
23 
24 struct dirent;
25 
26 /* Determine whether a path is an absolute path. */
27 int got_path_is_absolute(const char *);
28 
29 /*
30  * Canonicalize absolute paths by removing redundant path separators
31  * and resolving references to parent directories ("/../").
32  * Relative paths are copied from input to buf as-is.
33  */
34 const struct got_error *got_canonpath(const char *, char *, size_t);
35 
36 /*
37  * Get child part of two absolute paths. The second path must equal the first
38  * path up to some path component, and must be longer than the first path.
39  * The result is allocated with malloc(3).
40  */
41 const struct got_error *got_path_skip_common_ancestor(char **, const char *,
42     const char *);
43 
44 /*
45  * Remove leading components from path.  It's an error to strip more
46  * component than present.  The result is allocated dynamically.
47  */
48 const struct got_error *got_path_strip(char **, const char *, int);
49 
50 /* Determine whether a path points to the root directory "/" . */
51 int got_path_is_root_dir(const char *);
52 
53 /* Determine whether a path is a path-wise child of another path. */
54 int got_path_is_child(const char *, const char *, size_t);
55 
56 /*
57  * Like strcmp() but orders children in subdirectories directly after
58  * their parents. String lengths must also be passed in.
59  */
60 int got_path_cmp(const char *, const char *, size_t, size_t);
61 
62 /*
63  * Path lists allow for predictable concurrent iteration over multiple lists
64  * of paths obtained from disparate sources which don't all provide the same
65  * ordering guarantees (e.g. git trees, file index, and on-disk directories).
66  */
67 struct got_pathlist_entry {
68 	TAILQ_ENTRY(got_pathlist_entry) entry;
69 	const char *path;
70 	size_t path_len;
71 	void *data; /* data pointer provided to got_pathlist_insert() */
72 };
73 TAILQ_HEAD(got_pathlist_head, got_pathlist_entry);
74 
75 /*
76  * Insert a path into the list of paths in a predictable order.
77  * The caller should already have initialized the list head. This list stores
78  * the pointer to the path as-is, i.e. the path is not copied internally and
79  * must remain available until the list is freed with got_pathlist_free().
80  * If the first argument is not NULL, set it to a pointer to the newly inserted
81  * element, or to a NULL pointer in case the path was already on the list.
82  */
83 const struct got_error *got_pathlist_insert(struct got_pathlist_entry **,
84     struct got_pathlist_head *, const char *, void *);
85 
86 /*
87  * Append a path to the list of paths.
88  * The caller should already have initialized the list head. This list stores
89  * the pointer to the path as-is, i.e. the path is not copied internally and
90  * must remain available until the list is freed with got_pathlist_free().
91  */
92 const struct got_error *got_pathlist_append(struct got_pathlist_head *,
93     const char *, void *);
94 
95 /* Free resources allocated for a path list. */
96 void got_pathlist_free(struct got_pathlist_head *);
97 
98 /* Attempt to create a directory at a given path. */
99 const struct got_error *got_path_mkdir(const char *);
100 
101 /* Determine whether a directory has no files or directories in it. */
102 int got_path_dir_is_empty(const char *);
103 
104 /*
105  * dirname(3) with error handling, dynamically allocated result, and
106  * unmodified input.
107  */
108 const struct got_error *got_path_dirname(char **, const char *);
109 
110 /*
111  * Obtain the file type of a given directory entry.
112  *
113  * If the entry has some type other than DT_UNKNOWN, resolve to this type.
114  *
115  * Otherwise, attempt to resolve the type of a DT_UNKNOWN directory
116  * entry with lstat(2), though the result may still be DT_UNKNOWN.
117  * This is a fallback to accommodate filesystems which do not provide
118  * directory entry type information.
119  * DT_UNKNOWN directory entries occur on NFS mounts without "readdir plus" RPC.
120  */
121 const struct got_error *got_path_dirent_type(int *, const char *,
122     struct dirent *);
123 
124 /* basename(3) with dynamically allocated result and unmodified input. */
125 const struct got_error *got_path_basename(char **, const char *);
126 
127 /* Strip trailing slashes from a path; path will be modified in-place. */
128 void got_path_strip_trailing_slashes(char *);
129 
130 /* Look up the absolute path of a program in $PATH */
131 const struct got_error *got_path_find_prog(char **, const char *);
132 
133 /* Create a new file at a specified path, with optional content. */
134 const struct got_error *got_path_create_file(const char *, const char *);
135 
136 /*
137  * Attempt to move an existing file to a new path, creating missing parent
138  * directories at the destination path if necessary.
139  * (Cross-mount-point moves are not yet implemented.)
140  */
141 const struct got_error *got_path_move_file(const char *, const char *);