1 #include <sys/stat.h>
2 #include <fcntl.h>
3 #include <errno.h>
4 #include "syscall.h"
5
fchmodat(int fd,const char * path,mode_t mode,int flag)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 int ret;
10 #ifdef SYS_fchmodat2
11 ret = __syscall(SYS_fchmodat2, fd, path, mode, flag);
12 if (ret != -ENOSYS) return __syscall_ret(ret);
13 #endif
14
15 if (flag != AT_SYMLINK_NOFOLLOW)
16 return __syscall_ret(-EINVAL);
17
18 struct stat st;
19 int fd2;
20 char proc[15+3*sizeof(int)];
21
22 if (fstatat(fd, path, &st, flag))
23 return -1;
24 if (S_ISLNK(st.st_mode))
25 return __syscall_ret(-EOPNOTSUPP);
26
27 if ((fd2 = __syscall(SYS_openat, fd, path, O_RDONLY|O_PATH|O_NOFOLLOW|O_NOCTTY|O_CLOEXEC)) < 0) {
28 if (fd2 == -ELOOP)
29 return __syscall_ret(-EOPNOTSUPP);
30 return __syscall_ret(fd2);
31 }
32
33 __procfdname(proc, fd2);
34 ret = stat(proc, &st);
35 if (!ret) {
36 if (S_ISLNK(st.st_mode)) ret = __syscall_ret(-EOPNOTSUPP);
37 else ret = syscall(SYS_fchmodat, AT_FDCWD, proc, mode);
38 }
39
40 __syscall(SYS_close, fd2);
41 return ret;
42 }
43