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