tools/perf/util/path.c

   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 static char *get_pathname(void)
  26 {
  27         static char pathname_array[4][PATH_MAX];
  28         static int idx;
  29
  30         return pathname_array[3 & ++idx];
  31 }
  32
  33 static char *cleanup_path(char *path)
  34 {
  35         /* Clean it up */
  36         if (!memcmp(path, "./", 2)) {
  37                 path += 2;
  38                 while (*path == '/')
  39                         path++;
  40         }
  41         return path;
  42 }
  43
  44 char *mkpath(const char *fmt, ...)
  45 {
  46         va_list args;
  47         unsigned len;
  48         char *pathname = get_pathname();
  49
  50         va_start(args, fmt);
  51         len = vsnprintf(pathname, PATH_MAX, fmt, args);
  52         va_end(args);
  53         if (len >= PATH_MAX)
  54                 return bad_path;
  55         return cleanup_path(pathname);
  56 }
  57
  58 char *perf_path(const char *fmt, ...)
  59 {
  60         const char *perf_dir = get_perf_dir();
  61         char *pathname = get_pathname();
  62         va_list args;
  63         unsigned len;
  64
  65         len = strlen(perf_dir);
  66         if (len > PATH_MAX-100)
  67                 return bad_path;
  68         memcpy(pathname, perf_dir, len);
  69         if (len && perf_dir[len-1] != '/')
  70                 pathname[len++] = '/';
  71         va_start(args, fmt);
  72         len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
  73         va_end(args);
  74         if (len >= PATH_MAX)
  75                 return bad_path;
  76         return cleanup_path(pathname);
  77 }
  78
  79 /* strip arbitrary amount of directory separators at end of path */
  80 static inline int chomp_trailing_dir_sep(const char *path, int len)
  81 {
  82         while (len && is_dir_sep(path[len - 1]))
  83                 len--;
  84         return len;
  85 }
  86
  87 /*
  88  * If path ends with suffix (complete path components), returns the
  89  * part before suffix (sans trailing directory separators).
  90  * Otherwise returns NULL.
  91  */
  92 char *strip_path_suffix(const char *path, const char *suffix)
  93 {
  94         int path_len = strlen(path), suffix_len = strlen(suffix);
  95
  96         while (suffix_len) {
  97                 if (!path_len)
  98                         return NULL;
  99
 100                 if (is_dir_sep(path[path_len - 1])) {
 101                         if (!is_dir_sep(suffix[suffix_len - 1]))
 102                                 return NULL;
 103                         path_len = chomp_trailing_dir_sep(path, path_len);
 104                         suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
 105                 }
 106                 else if (path[--path_len] != suffix[--suffix_len])
 107                         return NULL;
 108         }
 109
 110         if (path_len && !is_dir_sep(path[path_len - 1]))
 111                 return NULL;
 112         return strndup(path, chomp_trailing_dir_sep(path, path_len));
 113 }