Function relname

zic.c:1675–1714

Create symlink contents suitable for symlinking TARGET to LINKNAME, as a freshly allocated string. TARGET should be a relative file name, and is relative to the global variable DIRECTORY. LINKNAME can be either relative or absolute. Return a null pointer if the symlink contents was not computed because LINKNAME is absolute but DIRECTORY is not. */

remove_temp(char const *temp)
{
  if (remove(temp) < 0)
    fprintf(stderr, _("%s: Can't remove temporary file %s%s%s: %s\n"),
	    progname, diagdir(temp), diagslash(temp), temp, strerror(errno));
}

/* Create symlink contents suitable for symlinking TARGET to LINKNAME, as a
   freshly allocated string.  TARGET should be a relative file name, and
   is relative to the global variable DIRECTORY.  LINKNAME can be either
   relative or absolute.  Return a null pointer if the symlink contents
   was not computed because LINKNAME is absolute but DIRECTORY is not.  */
static char *
relname(char const *target, char const *linkname)
{
  size_t i, taillen, dir_len = 0, dotdots = 0;
  ptrdiff_t dotdotetcsize, linksize = INDEX_MAX;
  char const *f = target;
  char *result = NULL;
  if (*linkname == '/') {
    /* Make F absolute too.  */
    size_t len = strlen(directory);
    bool needs_slash = len && directory[len - 1] != '/';
    size_t lenslash = len + needs_slash;
    size_t targetsize = strlen(target) + 1;
    char *cp;
    if (*directory != '/')
      return NULL;
    linksize = size_sum(lenslash, targetsize);
    f = cp = result = xmalloc(linksize);
    cp = mempcpy(cp, directory, len);
    *cp = '/';
    memcpy(cp + needs_slash, target, targetsize);
  }
  for (i = 0; f[i] && f[i] == linkname[i]; i++)
    if (f[i] == '/')
      dir_len = i + 1;
  for (; linkname[i]; i++)
    dotdots += linkname[i] == '/' && linkname[i - 1] != '/';
  taillen = strlen(f + dir_len);
  dotdotetcsize = size_sum(size_product(dotdots, 3), taillen + 1);
  if (dotdotetcsize <= linksize) {
    char *cp;
    if (!result)
      result = xmalloc(dotdotetcsize);