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 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 */ 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 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 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 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 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 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 } 105 106 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 */ 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 */ 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