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 #ifdef NO_STRLCPY
  26 size_t strlcpy(char *dest, const char *src, size_t size)
  27 {
  28         size_t ret = strlen(src);
  29
  30         if (size) {
  31                 size_t len = (ret >= size) ? size - 1 : ret;
  32                 memcpy(dest, src, len);
  33                 dest[len] = '\0';
  34         }
  35         return ret;
  36 }
  37 #endif
  38
  39 static char *get_pathname(void)
  40 {
  41         static char pathname_array[4][PATH_MAX];
  42         static int idx;
  43
  44         return pathname_array[3 & ++idx];
  45 }
  46
  47 static char *cleanup_path(char *path)
  48 {
  49         /* Clean it up */
  50         if (!memcmp(path, "./", 2)) {
  51                 path += 2;
  52                 while (*path == '/')
  53                         path++;
  54         }
  55         return path;
  56 }
  57
  58 static char *perf_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
  59 {
  60         const char *perf_dir = get_perf_dir();
  61         size_t len;
  62
  63         len = strlen(perf_dir);
  64         if (n < len + 1)
  65                 goto bad;
  66         memcpy(buf, perf_dir, len);
  67         if (len && !is_dir_sep(perf_dir[len-1]))
  68                 buf[len++] = '/';
  69         len += vsnprintf(buf + len, n - len, fmt, args);
  70         if (len >= n)
  71                 goto bad;
  72         return cleanup_path(buf);
  73 bad:
  74         strlcpy(buf, bad_path, n);
  75         return buf;
  76 }
  77
  78 char *perf_pathdup(const char *fmt, ...)
  79 {
  80         char path[PATH_MAX];
  81         va_list args;
  82         va_start(args, fmt);
  83         (void)perf_vsnpath(path, sizeof(path), fmt, args);
  84         va_end(args);
  85         return xstrdup(path);
  86 }
  87
  88 char *mkpath(const char *fmt, ...)
  89 {
  90         va_list args;
  91         unsigned len;
  92         char *pathname = get_pathname();
  93
  94         va_start(args, fmt);
  95         len = vsnprintf(pathname, PATH_MAX, fmt, args);
  96         va_end(args);
  97         if (len >= PATH_MAX)
  98                 return bad_path;
  99         return cleanup_path(pathname);
 100 }
 101
 102 char *perf_path(const char *fmt, ...)
 103 {
 104         const char *perf_dir = get_perf_dir();
 105         char *pathname = get_pathname();
 106         va_list args;
 107         unsigned len;
 108
 109         len = strlen(perf_dir);
 110         if (len > PATH_MAX-100)
 111                 return bad_path;
 112         memcpy(pathname, perf_dir, len);
 113         if (len && perf_dir[len-1] != '/')
 114                 pathname[len++] = '/';
 115         va_start(args, fmt);
 116         len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
 117         va_end(args);
 118         if (len >= PATH_MAX)
 119                 return bad_path;
 120         return cleanup_path(pathname);
 121 }
 122
 123 /* strip arbitrary amount of directory separators at end of path */
 124 static inline int chomp_trailing_dir_sep(const char *path, int len)
 125 {
 126         while (len && is_dir_sep(path[len - 1]))
 127                 len--;
 128         return len;
 129 }
 130
 131 /*
 132  * If path ends with suffix (complete path components), returns the
 133  * part before suffix (sans trailing directory separators).
 134  * Otherwise returns NULL.
 135  */
 136 char *strip_path_suffix(const char *path, const char *suffix)
 137 {
 138         int path_len = strlen(path), suffix_len = strlen(suffix);
 139
 140         while (suffix_len) {
 141                 if (!path_len)
 142                         return NULL;
 143
 144                 if (is_dir_sep(path[path_len - 1])) {
 145                         if (!is_dir_sep(suffix[suffix_len - 1]))
 146                                 return NULL;
 147                         path_len = chomp_trailing_dir_sep(path, path_len);
 148                         suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
 149                 }
 150                 else if (path[--path_len] != suffix[--suffix_len])
 151                         return NULL;
 152         }
 153
 154         if (path_len && !is_dir_sep(path[path_len - 1]))
 155                 return NULL;
 156         return strndup(path, chomp_trailing_dir_sep(path, path_len));
 157 }