int fchmodat(int fd, const char *path, mode_t mode, int flag)
{
if (!flag) return syscall(SYS_fchmodat, fd, path, mode, flag);
if (flag != AT_SYMLINK_NOFOLLOW)
return __syscall_ret(-EINVAL);
struct stat st;
int ret, fd2;
char proc[15+3*sizeof(int)];
if ((ret = __syscall(SYS_fstatat, fd, path, &st, flag)))
return __syscall_ret(ret);
if (S_ISLNK(st.st_mode))
return __syscall_ret(-EOPNOTSUPP);
if ((fd2 = __syscall(SYS_openat, fd, path, O_RDONLY|O_PATH|O_NOFOLLOW|O_NOCTTY)) < 0) {
if (fd2 == -ELOOP)
return __syscall_ret(-EOPNOTSUPP);
return __syscall_ret(fd2);
}
__procfdname(proc, fd2);
if (!(ret = __syscall(SYS_stat, proc, &st)) && !S_ISLNK(st.st_mode))
ret = __syscall(SYS_chmod, proc, mode);
__syscall(SYS_close, fd2);
return __syscall_ret(ret);
}
int fexecve(int fd, char *const argv[], char *const envp[])
{
char buf[15 + 3*sizeof(int)];
__procfdname(buf, fd);
execve(buf, argv, envp);
if (errno == ENOENT) errno = EBADF;
return -1;
}
int fchdir(int fd)
{
int ret = __syscall(SYS_fchdir, fd);
if (ret != -EBADF || fd < 0) return __syscall_ret(ret);
char buf[15+3*sizeof(int)];
__procfdname(buf, fd);
return syscall(SYS_chdir, buf);
}
int fstat(int fd, struct stat *st)
{
int ret = __syscall(SYS_fstat, fd, mcfi_sandbox_mask(st));
if (ret != -EBADF || __syscall(SYS_fcntl, fd, F_GETFD) < 0)
return __syscall_ret(ret);
char buf[15+3*sizeof(int)];
__procfdname(buf, fd);
return syscall(SYS_stat, buf, mcfi_sandbox_mask(st));
}
int fexecve(int fd, char *const argv[], char *const envp[])
{
int r = __syscall(SYS_execveat, fd, "", argv, envp, AT_EMPTY_PATH);
if (r != -ENOSYS) return __syscall_ret(r);
char buf[15 + 3*sizeof(int)];
__procfdname(buf, fd);
execve(buf, argv, envp);
if (errno == ENOENT) errno = EBADF;
return -1;
}
int fstat(int fd, struct stat* st) {
int ret = __syscall(SYS_fstat, fd, st);
if (ret != -EBADF || __syscall(SYS_fcntl, fd, F_GETFD) < 0)
return __syscall_ret(ret);
char buf[15 + 3 * sizeof(int)];
__procfdname(buf, fd);
#ifdef SYS_stat
return syscall(SYS_stat, buf, st);
#else
return syscall(SYS_fstatat, AT_FDCWD, buf, st, 0);
#endif
}
int ttyname_r(int fd, char *name, size_t size)
{
char procname[sizeof "/proc/self/fd/" + 3*sizeof(int) + 2];
ssize_t l;
if (!isatty(fd)) return ENOTTY;
__procfdname(procname, fd);
l = readlink(procname, name, size);
if (l < 0) return errno;
else if (l == size) return ERANGE;
else {
name[l] = 0;
return 0;
}
}
int ttyname_r(int fd, char *name, size_t size)
{
struct stat st1, st2;
char procname[sizeof "/proc/self/fd/" + 3*sizeof(int) + 2];
ssize_t l;
if (!isatty(fd)) return errno;
__procfdname(procname, fd);
l = readlink(procname, name, size);
if (l < 0) return errno;
else if (l == size) return ERANGE;
name[l] = 0;
if (stat(name, &st1) || fstat(fd, &st2))
return errno;
if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
return ENODEV;
return 0;
}