1#include <sys/stat.h> 2#include <fcntl.h> 3#include <errno.h> 4#include "syscall.h" 5 6int 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