pub unsafe fn fstat(fd: i32, statbuf: &mut stat_t) -> Result<(), Errno>Expand description
Get file status about a file descriptor.
ยงexample
let path = "/tmp";
// Open folder directly.
let fd = unsafe { nc::openat(nc::AT_FDCWD, path, nc::O_PATH, 0) };
assert!(fd.is_ok());
let fd = fd.unwrap();
let mut stat = nc::stat_t::default();
let ret = unsafe { nc::fstat(fd, &mut stat) };
assert!(ret.is_ok());
// Check fd is a directory.
assert!(nc::S_ISDIR(stat.st_mode as nc::mode_t));
let ret = unsafe { nc::close(fd) };
assert!(ret.is_ok());Examples found in repository?
examples/mmap.rs (line 15)
8fn main() {
9 let path = "/etc/passwd";
10 let fd = unsafe { nc::openat(nc::AT_FDCWD, path, nc::O_RDONLY, 0o644) };
11 assert!(fd.is_ok());
12 let fd = fd.unwrap();
13
14 let mut sb = nc::stat_t::default();
15 let ret = unsafe { nc::fstat(fd, &mut sb) };
16 assert!(ret.is_ok());
17
18 let offset: usize = 0;
19 let length: usize = sb.st_size as usize - offset;
20 // Offset for mmap must be page aligned.
21 let pa_offset: usize = offset & !(nc::PAGE_SIZE - 1);
22 let map_length = length + offset - pa_offset;
23
24 #[cfg(target_arch = "arm")]
25 let addr = unsafe {
26 nc::mmap2(
27 ptr::null(),
28 map_length,
29 nc::PROT_READ,
30 nc::MAP_PRIVATE,
31 fd,
32 pa_offset as nc::off_t,
33 )
34 };
35 #[cfg(not(target_arch = "arm"))]
36 let addr = unsafe {
37 nc::mmap(
38 ptr::null(),
39 map_length,
40 nc::PROT_READ,
41 nc::MAP_PRIVATE,
42 fd,
43 pa_offset as nc::off_t,
44 )
45 };
46 assert!(addr.is_ok());
47 let addr: *const c_void = addr.unwrap();
48
49 let stdout = 1;
50 // Create the "fat pointer".
51 // let buf = unsafe {
52 // mem::transmute::<(usize, usize), &[u8]>((addr as usize + offset - pa_offset, length))
53 // };
54 // Create buffer slice.
55 let buf: &[u8] = unsafe {
56 &*ptr::slice_from_raw_parts(
57 addr.wrapping_add(offset)
58 .wrapping_sub(pa_offset)
59 .cast::<u8>(),
60 length,
61 )
62 };
63 let n_write = unsafe { nc::write(stdout, buf) };
64 assert!(n_write.is_ok());
65 assert_eq!(n_write, Ok(length as nc::ssize_t));
66 let ret = unsafe { nc::munmap(addr, map_length) };
67 assert!(ret.is_ok());
68 let ret = unsafe { nc::close(fd) };
69 assert!(ret.is_ok());
70}