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, flag);
   9
  10         if (flag != AT_SYMLINK_NOFOLLOW)
  11                 return __syscall_ret(-EINVAL);
  12
  13         struct stat st;
  14         int ret, fd2;
  15         char proc[15+3*sizeof(int)];
  16
  17         if ((ret = __syscall(SYS_fstatat, fd, path, &st, flag)))
  18                 return __syscall_ret(ret);
  19         if (S_ISLNK(st.st_mode))
  20                 return __syscall_ret(-EOPNOTSUPP);
  21
  22         if ((fd2 = __syscall(SYS_openat, fd, path, O_RDONLY|O_PATH|O_NOFOLLOW|O_NOCTTY|O_CLOEXEC)) < 0) {
  23                 if (fd2 == -ELOOP)
  24                         return __syscall_ret(-EOPNOTSUPP);
  25                 return __syscall_ret(fd2);
  26         }
  27
  28         __procfdname(proc, fd2);
  29         ret = __syscall(SYS_fstatat, AT_FDCWD, proc, &st, 0);
  30         if (!ret) {
  31                 if (S_ISLNK(st.st_mode)) ret = -EOPNOTSUPP;
  32                 else ret = __syscall(SYS_fchmodat, AT_FDCWD, proc, mode);
  33         }
  34
  35         __syscall(SYS_close, fd2);
  36         return __syscall_ret(ret);
  37 }