src/stat/fchmodat.c

   1 #include <sys/stat.h>
   2 #include <fcntl.h>
   3 #include <errno.h>
   4 #include "syscall.h"
   5
   6 int fchmodat(int fd, const char *path, mode_t mode, int flag)
   7 {
   8         if (!flag) return syscall(SYS_fchmodat, fd, path, mode);
   9
  10         int ret = __syscall(SYS_fchmodat2, fd, path, mode, flag);
  11         if (ret != -ENOSYS) return __syscall_ret(ret);
  12
  13         if (flag != AT_SYMLINK_NOFOLLOW)
  14                 return __syscall_ret(-EINVAL);
  15
  16         struct stat st;
  17         int fd2;
  18         char proc[15+3*sizeof(int)];
  19
  20         if (fstatat(fd, path, &st, flag))
  21                 return -1;
  22         if (S_ISLNK(st.st_mode))
  23                 return __syscall_ret(-EOPNOTSUPP);
  24
  25         if ((fd2 = __syscall(SYS_openat, fd, path, O_RDONLY|O_PATH|O_NOFOLLOW|O_NOCTTY|O_CLOEXEC)) < 0) {
  26                 if (fd2 == -ELOOP)
  27                         return __syscall_ret(-EOPNOTSUPP);
  28                 return __syscall_ret(fd2);
  29         }
  30
  31         __procfdname(proc, fd2);
  32         ret = stat(proc, &st);
  33         if (!ret) {
  34                 if (S_ISLNK(st.st_mode)) ret = __syscall_ret(-EOPNOTSUPP);
  35                 else ret = syscall(SYS_fchmodat, AT_FDCWD, proc, mode);
  36         }
  37
  38         __syscall(SYS_close, fd2);
  39         return ret;
  40 }