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_PACK_MODE	(S_IFREG | \
20 	S_IRUSR | S_IRGRP | S_IROTH)
21 #define GOT_DEFAULT_FILE_MODE	(S_IFREG | \
22 	S_IRUSR|S_IWUSR | S_IRGRP | S_IROTH)
23 #define GOT_DEFAULT_DIR_MODE	(S_IFDIR | \
24 	S_IRWXU | S_IRGRP|S_IXGRP | S_IROTH|S_IXOTH)
25 
26 struct dirent;
27 
28 /* Determine whether a path is an absolute path. */
29 int got_path_is_absolute(const char *);
30 
31 /*
32  * Canonicalize absolute paths by removing redundant path separators
33  * and resolving references to parent directories ("/../").
34  * Relative paths are copied from input to buf as-is.
35  */
36 const struct got_error *got_canonpath(const char *, char *, size_t);
37 
38 /*
39  * Get child part of two absolute paths. The second path must equal the first
40  * path up to some path component, and must be longer than the first path.
41  * The result is allocated with malloc(3).
42  */
43 const struct got_error *got_path_skip_common_ancestor(char **, const char *,
44     const char *);
45 
46 /*
47  * Remove leading components from path.  It's an error to strip more
48  * component than present.  The result is allocated dynamically.
49  */
50 const struct got_error *got_path_strip(char **, const char *, int);
51 
52 /* Determine whether a path points to the root directory "/" . */
53 int got_path_is_root_dir(const char *);
54 
55 /* Determine whether a path is a path-wise child of another path. */
56 int got_path_is_child(const char *, const char *, size_t);
57 
58 /*
59  * Like strcmp() but orders children in subdirectories directly after
60  * their parents. String lengths must also be passed in.
61  */
62 int got_path_cmp(const char *, const char *, size_t, size_t);
63 
64 /*
65  * Path lists allow for predictable concurrent iteration over multiple lists
66  * of paths obtained from disparate sources which don't all provide the same
67  * ordering guarantees (e.g. git trees, file index, and on-disk directories).
68  */
69 struct got_pathlist_entry {
70 	TAILQ_ENTRY(got_pathlist_entry) entry;
71 	const char *path;
72 	size_t path_len;
73 	void *data; /* data pointer provided to got_pathlist_insert() */
74 };
75 TAILQ_HEAD(got_pathlist_head, got_pathlist_entry);
76 
77 /*
78  * Insert a path into the list of paths in a predictable order.
79  * The caller should already have initialized the list head. This list stores
80  * the pointer to the path as-is, i.e. the path is not copied internally and
81  * must remain available until the list is freed with got_pathlist_free().
82  * If the first argument is not NULL, set it to a pointer to the newly inserted
83  * element, or to a NULL pointer in case the path was already on the list.
84  */
85 const struct got_error *got_pathlist_insert(struct got_pathlist_entry **,
86     struct got_pathlist_head *, const char *, void *);
87 
88 /*
89  * Append a path to the list of paths.
90  * The caller should already have initialized the list head. This list stores
91  * the pointer to the path as-is, i.e. the path is not copied internally and
92  * must remain available until the list is freed with got_pathlist_free().
93  */
94 const struct got_error *got_pathlist_append(struct got_pathlist_head *,
95     const char *, void *);
96 
97 /* Flags passed to got_pathlist_free() to control which pointers are freed. */
98 #define GOT_PATHLIST_FREE_NONE	0	  /* pathlist entry only */
99 #define GOT_PATHLIST_FREE_PATH	(1 << 0)  /* entry and path pointer */
100 #define GOT_PATHLIST_FREE_DATA	(1 << 1)  /* entry and data pointer */
101 #define GOT_PATHLIST_FREE_ALL	(GOT_PATHLIST_FREE_PATH|GOT_PATHLIST_FREE_DATA)
102 
103 /* Free resources allocated for a path list. */
104 void got_pathlist_free(struct got_pathlist_head *, int);
105 
106 /* Attempt to create a directory at a given path. */
107 const struct got_error *got_path_mkdir(const char *);
108 
109 /* Determine whether a directory has no files or directories in it. */
110 int got_path_dir_is_empty(const char *);
111 
112 /*
113  * dirname(3) with error handling, dynamically allocated result, and
114  * unmodified input.
115  */
116 const struct got_error *got_path_dirname(char **, const char *);
117 
118 /*
119  * Obtain the file type of a given directory entry.
120  *
121  * If the entry has some type other than DT_UNKNOWN, resolve to this type.
122  *
123  * Otherwise, attempt to resolve the type of a DT_UNKNOWN directory
124  * entry with lstat(2), though the result may still be DT_UNKNOWN.
125  * This is a fallback to accommodate filesystems which do not provide
126  * directory entry type information.
127  * DT_UNKNOWN directory entries occur on NFS mounts without "readdir plus" RPC.
128  */
129 const struct got_error *got_path_dirent_type(int *, const char *,
130     struct dirent *);
131 
132 /* basename(3) with dynamically allocated result and unmodified input. */
133 const struct got_error *got_path_basename(char **, const char *);
134 
135 /* Strip trailing slashes from a path; path will be modified in-place. */
136 void got_path_strip_trailing_slashes(char *);
137 
138 /* Look up the absolute path of a program in $PATH */
139 const struct got_error *got_path_find_prog(char **, const char *);
140 
141 /* Create a new file at a specified path, with optional content. */
142 const struct got_error *got_path_create_file(const char *, const char *);
143 
144 /*
145  * Attempt to move an existing file to a new path, creating missing parent
146  * directories at the destination path if necessary.
147  * (Cross-mount-point moves are not yet implemented.)
148  */
149 const struct got_error *got_path_move_file(const char *, const char *);