1/*
2 * I'm tired of doing "vsnprintf()" etc just to open a
3 * file, so here's a "return static buffer with printf"
4 * interface for paths.
5 *
6 * It's obviously not thread-safe. Sue me. But it's quite
7 * useful for doing things like
8 *
9 *   f = open(mkpath("%s/%s.perf", base, name), O_RDONLY);
10 *
11 * which is what it's designed for.
12 */
13#include "cache.h"
14
15static char bad_path[] = "/bad-path/";
16/*
17 * Two hacks:
18 */
19
20static const char *get_perf_dir(void)
21{
22	return ".";
23}
24
25/*
26 * If libc has strlcpy() then that version will override this
27 * implementation:
28 */
29size_t __weak strlcpy(char *dest, const char *src, size_t size)
30{
31	size_t ret = strlen(src);
32
33	if (size) {
34		size_t len = (ret >= size) ? size - 1 : ret;
35
36		memcpy(dest, src, len);
37		dest[len] = '\0';
38	}
39
40	return ret;
41}
42
43static char *get_pathname(void)
44{
45	static char pathname_array[4][PATH_MAX];
46	static int idx;
47
48	return pathname_array[3 & ++idx];
49}
50
51static char *cleanup_path(char *path)
52{
53	/* Clean it up */
54	if (!memcmp(path, "./", 2)) {
55		path += 2;
56		while (*path == '/')
57			path++;
58	}
59	return path;
60}
61
62static char *perf_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
63{
64	const char *perf_dir = get_perf_dir();
65	size_t len;
66
67	len = strlen(perf_dir);
68	if (n < len + 1)
69		goto bad;
70	memcpy(buf, perf_dir, len);
71	if (len && !is_dir_sep(perf_dir[len-1]))
72		buf[len++] = '/';
73	len += vsnprintf(buf + len, n - len, fmt, args);
74	if (len >= n)
75		goto bad;
76	return cleanup_path(buf);
77bad:
78	strlcpy(buf, bad_path, n);
79	return buf;
80}
81
82char *perf_pathdup(const char *fmt, ...)
83{
84	char path[PATH_MAX];
85	va_list args;
86	va_start(args, fmt);
87	(void)perf_vsnpath(path, sizeof(path), fmt, args);
88	va_end(args);
89	return xstrdup(path);
90}
91
92char *mkpath(const char *fmt, ...)
93{
94	va_list args;
95	unsigned len;
96	char *pathname = get_pathname();
97
98	va_start(args, fmt);
99	len = vsnprintf(pathname, PATH_MAX, fmt, args);
100	va_end(args);
101	if (len >= PATH_MAX)
102		return bad_path;
103	return cleanup_path(pathname);
104}
105
106char *perf_path(const char *fmt, ...)
107{
108	const char *perf_dir = get_perf_dir();
109	char *pathname = get_pathname();
110	va_list args;
111	unsigned len;
112
113	len = strlen(perf_dir);
114	if (len > PATH_MAX-100)
115		return bad_path;
116	memcpy(pathname, perf_dir, len);
117	if (len && perf_dir[len-1] != '/')
118		pathname[len++] = '/';
119	va_start(args, fmt);
120	len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
121	va_end(args);
122	if (len >= PATH_MAX)
123		return bad_path;
124	return cleanup_path(pathname);
125}
126
127/* strip arbitrary amount of directory separators at end of path */
128static inline int chomp_trailing_dir_sep(const char *path, int len)
129{
130	while (len && is_dir_sep(path[len - 1]))
131		len--;
132	return len;
133}
134
135/*
136 * If path ends with suffix (complete path components), returns the
137 * part before suffix (sans trailing directory separators).
138 * Otherwise returns NULL.
139 */
140char *strip_path_suffix(const char *path, const char *suffix)
141{
142	int path_len = strlen(path), suffix_len = strlen(suffix);
143
144	while (suffix_len) {
145		if (!path_len)
146			return NULL;
147
148		if (is_dir_sep(path[path_len - 1])) {
149			if (!is_dir_sep(suffix[suffix_len - 1]))
150				return NULL;
151			path_len = chomp_trailing_dir_sep(path, path_len);
152			suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
153		}
154		else if (path[--path_len] != suffix[--suffix_len])
155			return NULL;
156	}
157
158	if (path_len && !is_dir_sep(path[path_len - 1]))
159		return NULL;
160	return strndup(path, chomp_trailing_dir_sep(path, path_len));
161}
162