src/stat/fchmodat.c

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