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
15 static char bad_path[] = "/bad-path/";
16 /*
17 * Two hacks:
18 */
19
get_perf_dir(void)20 static 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 */
strlcpy(char * dest,const char * src,size_t size)29 size_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
get_pathname(void)43 static 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
cleanup_path(char * path)51 static 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
perf_vsnpath(char * buf,size_t n,const char * fmt,va_list args)62 static 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);
77 bad:
78 strlcpy(buf, bad_path, n);
79 return buf;
80 }
81
perf_pathdup(const char * fmt,...)82 char *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
mkpath(const char * fmt,...)92 char *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
perf_path(const char * fmt,...)106 char *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 */
chomp_trailing_dir_sep(const char * path,int len)128 static 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 */
strip_path_suffix(const char * path,const char * suffix)140 char *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