abspath.c

   1 #include "cache.h"
   2
   3 /* We allow "recursive" symbolic links. Only within reason, though. */
   4 #define MAXDEPTH 5
   5
   6 const char *make_absolute_path(const char *path)
   7 {
   8         static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
   9         char cwd[1024] = "";
  10         int buf_index = 1, len;
  11
  12         int depth = MAXDEPTH;
  13         char *last_elem = NULL;
  14         struct stat st;
  15
  16         if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
  17                 die ("Too long path: %.*s", 60, path);
  18
  19         while (depth--) {
  20                 if (stat(buf, &st) || !S_ISDIR(st.st_mode)) {
  21                         char *last_slash = strrchr(buf, '/');
  22                         if (last_slash) {
  23                                 *last_slash = '\0';
  24                                 last_elem = xstrdup(last_slash + 1);
  25                         } else {
  26                                 last_elem = xstrdup(buf);
  27                                 *buf = '\0';
  28                         }
  29                 }
  30
  31                 if (*buf) {
  32                         if (!*cwd && !getcwd(cwd, sizeof(cwd)))
  33                                 die ("Could not get current working directory");
  34
  35                         if (chdir(buf))
  36                                 die ("Could not switch to '%s'", buf);
  37                 }
  38                 if (!getcwd(buf, PATH_MAX))
  39                         die ("Could not get current working directory");
  40
  41                 if (last_elem) {
  42                         int len = strlen(buf);
  43                         if (len + strlen(last_elem) + 2 > PATH_MAX)
  44                                 die ("Too long path name: '%s/%s'",
  45                                                 buf, last_elem);
  46                         buf[len] = '/';
  47                         strcpy(buf + len + 1, last_elem);
  48                         free(last_elem);
  49                         last_elem = NULL;
  50                 }
  51
  52                 if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
  53                         len = readlink(buf, next_buf, PATH_MAX);
  54                         if (len < 0)
  55                                 die ("Invalid symlink: %s", buf);
  56                         next_buf[len] = '\0';
  57                         buf = next_buf;
  58                         buf_index = 1 - buf_index;
  59                         next_buf = bufs[buf_index];
  60                 } else
  61                         break;
  62         }
  63
  64         if (*cwd && chdir(cwd))
  65                 die ("Could not change back to '%s'", cwd);
  66
  67         return buf;
  68 }