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 static char *perf_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
  45 {
  46         const char *perf_dir = get_perf_dir();
  47         size_t len;
  48
  49         len = strlen(perf_dir);
  50         if (n < len + 1)
  51                 goto bad;
  52         memcpy(buf, perf_dir, len);
  53         if (len && !is_dir_sep(perf_dir[len-1]))
  54                 buf[len++] = '/';
  55         len += vsnprintf(buf + len, n - len, fmt, args);
  56         if (len >= n)
  57                 goto bad;
  58         return cleanup_path(buf);
  59 bad:
  60         strlcpy(buf, bad_path, n);
  61         return buf;
  62 }
  63
  64 char *perf_pathdup(const char *fmt, ...)
  65 {
  66         char path[PATH_MAX];
  67         va_list args;
  68         va_start(args, fmt);
  69         (void)perf_vsnpath(path, sizeof(path), fmt, args);
  70         va_end(args);
  71         return xstrdup(path);
  72 }
  73
  74 char *mkpath(const char *fmt, ...)
  75 {
  76         va_list args;
  77         unsigned len;
  78         char *pathname = get_pathname();
  79
  80         va_start(args, fmt);
  81         len = vsnprintf(pathname, PATH_MAX, fmt, args);
  82         va_end(args);
  83         if (len >= PATH_MAX)
  84                 return bad_path;
  85         return cleanup_path(pathname);
  86 }
  87
  88 char *perf_path(const char *fmt, ...)
  89 {
  90         const char *perf_dir = get_perf_dir();
  91         char *pathname = get_pathname();
  92         va_list args;
  93         unsigned len;
  94
  95         len = strlen(perf_dir);
  96         if (len > PATH_MAX-100)
  97                 return bad_path;
  98         memcpy(pathname, perf_dir, len);
  99         if (len && perf_dir[len-1] != '/')
 100                 pathname[len++] = '/';
 101         va_start(args, fmt);
 102         len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
 103         va_end(args);
 104         if (len >= PATH_MAX)
 105                 return bad_path;
 106         return cleanup_path(pathname);
 107 }
 108
 109 /* strip arbitrary amount of directory separators at end of path */
 110 static inline int chomp_trailing_dir_sep(const char *path, int len)
 111 {
 112         while (len && is_dir_sep(path[len - 1]))
 113                 len--;
 114         return len;
 115 }
 116
 117 /*
 118  * If path ends with suffix (complete path components), returns the
 119  * part before suffix (sans trailing directory separators).
 120  * Otherwise returns NULL.
 121  */
 122 char *strip_path_suffix(const char *path, const char *suffix)
 123 {
 124         int path_len = strlen(path), suffix_len = strlen(suffix);
 125
 126         while (suffix_len) {
 127                 if (!path_len)
 128                         return NULL;
 129
 130                 if (is_dir_sep(path[path_len - 1])) {
 131                         if (!is_dir_sep(suffix[suffix_len - 1]))
 132                                 return NULL;
 133                         path_len = chomp_trailing_dir_sep(path, path_len);
 134                         suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
 135                 }
 136                 else if (path[--path_len] != suffix[--suffix_len])
 137                         return NULL;
 138         }
 139
 140         if (path_len && !is_dir_sep(path[path_len - 1]))
 141                 return NULL;
 142         return strndup(path, chomp_trailing_dir_sep(path, path_len));
 143 }