- {
- struct stat proc_self_fd_dotdot_st;
- struct stat proc_self_st;
- char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof ".." - 1)];
- sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "..");
- proc_status =
- ((stat (dotdot_buf, &proc_self_fd_dotdot_st) == 0
- && stat ("/proc/self", &proc_self_st) == 0
- && SAME_INODE (proc_self_fd_dotdot_st, proc_self_st))
- ? 1 : -1);
- close (proc_self_fd);
- }
+ {
+ /* Detect whether /proc/self/fd/%i/../fd exists, where %i is the
+ number of a file descriptor open on /proc/self/fd. On Linux,
+ that name resolves to /proc/self/fd, which was opened above.
+ However, on Solaris, it may resolve to /proc/self/fd/fd, which
+ cannot exist, since all names in /proc/self/fd are numeric. */
+ char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof "../fd" - 1)];
+ sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "../fd");
+ proc_status = access (dotdot_buf, F_OK) ? -1 : 1;
+ close (proc_self_fd);
+ }