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Implement the mmap64 foreign item.

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`mmap64` is like `mmap` but uses a 64-bit integer instead of `off_t` for
the offset parameter.
This commit is contained in:
Dan Gohman 2024-01-30 08:28:12 -05:00
parent 71f8f4949e
commit a6f1dbac79
3 changed files with 122 additions and 2 deletions
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7
src/tools/miri/src/shims/unix/foreign_items.rs
View file

@ -262,9 +262,16 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
"mmap" => {
let [addr, length, prot, flags, fd, offset] = this.check_shim(abi, Abi::C {unwind: false}, link_name, args)?;
let offset = this.read_scalar(offset)?.to_int(this.libc_ty_layout("off_t").size)?;
let ptr = this.mmap(addr, length, prot, flags, fd, offset)?;
this.write_scalar(ptr, dest)?;
}
"mmap64" => {
let [addr, length, prot, flags, fd, offset] = this.check_shim(abi, Abi::C {unwind: false}, link_name, args)?;
let offset = this.read_scalar(offset)?.to_i64()?;
let ptr = this.mmap(addr, length, prot, flags, fd, offset.into())?;
this.write_scalar(ptr, dest)?;
}
"munmap" => {
let [addr, length] = this.check_shim(abi, Abi::C {unwind: false}, link_name, args)?;
let result = this.munmap(addr, length)?;

3
src/tools/miri/src/shims/unix/mem.rs
View file

@ -26,7 +26,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
prot: &OpTy<'tcx, Provenance>,
flags: &OpTy<'tcx, Provenance>,
fd: &OpTy<'tcx, Provenance>,
offset: &OpTy<'tcx, Provenance>,
offset: i128,
) -> InterpResult<'tcx, Scalar<Provenance>> {
let this = self.eval_context_mut();
@ -36,7 +36,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
let prot = this.read_scalar(prot)?.to_i32()?;
let flags = this.read_scalar(flags)?.to_i32()?;
let fd = this.read_scalar(fd)?.to_i32()?;
let offset = this.read_target_usize(offset)?;
let map_private = this.eval_libc_i32("MAP_PRIVATE");
let map_anonymous = this.eval_libc_i32("MAP_ANONYMOUS");

114
src/tools/miri/tests/pass-dep/shims/mmap.rs
View file

@ -116,6 +116,118 @@ fn test_mmap() {
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::EINVAL);
}
#[cfg(target_os = "linux")]
fn test_mmap64() {
let page_size = page_size::get();
let ptr = unsafe {
libc::mmap64(
ptr::null_mut(),
page_size,
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_PRIVATE | libc::MAP_ANONYMOUS,
-1,
0,
)
};
assert!(!ptr.is_null());
// Ensure that freshly mapped allocations are zeroed
let slice = unsafe { slice::from_raw_parts_mut(ptr as *mut u8, page_size) };
assert!(slice.iter().all(|b| *b == 0));
// Do some writes, make sure they worked
for b in slice.iter_mut() {
*b = 1;
}
assert!(slice.iter().all(|b| *b == 1));
// Ensure that we can munmap
let res = unsafe { libc::munmap(ptr, page_size) };
assert_eq!(res, 0i32);
// Test all of our error conditions
let ptr = unsafe {
libc::mmap64(
ptr::null_mut(),
page_size,
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_PRIVATE | libc::MAP_SHARED, // Can't be both private and shared
-1,
0,
)
};
assert_eq!(ptr, libc::MAP_FAILED);
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::EINVAL);
let ptr = unsafe {
libc::mmap64(
ptr::null_mut(),
0, // Can't map no memory
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_PRIVATE | libc::MAP_ANONYMOUS,
-1,
0,
)
};
assert_eq!(ptr, libc::MAP_FAILED);
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::EINVAL);
let ptr = unsafe {
libc::mmap64(
ptr::invalid_mut(page_size * 64),
page_size,
libc::PROT_READ | libc::PROT_WRITE,
// We don't support MAP_FIXED
libc::MAP_PRIVATE | libc::MAP_ANONYMOUS | libc::MAP_FIXED,
-1,
0,
)
};
assert_eq!(ptr, libc::MAP_FAILED);
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::ENOTSUP);
// We don't support protections other than read+write
for prot in [libc::PROT_NONE, libc::PROT_EXEC, libc::PROT_READ, libc::PROT_WRITE] {
let ptr = unsafe {
libc::mmap64(
ptr::null_mut(),
page_size,
prot,
libc::MAP_PRIVATE | libc::MAP_ANONYMOUS,
-1,
0,
)
};
assert_eq!(ptr, libc::MAP_FAILED);
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::ENOTSUP);
}
// We report an error for mappings whose length cannot be rounded up to a multiple of
// the page size.
let ptr = unsafe {
libc::mmap64(
ptr::null_mut(),
usize::MAX - 1,
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_PRIVATE | libc::MAP_ANONYMOUS,
-1,
0,
)
};
assert_eq!(ptr, libc::MAP_FAILED);
// We report an error when trying to munmap an address which is not a multiple of the page size
let res = unsafe { libc::munmap(ptr::invalid_mut(1), page_size) };
assert_eq!(res, -1);
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::EINVAL);
// We report an error when trying to munmap a length that cannot be rounded up to a multiple of
// the page size.
let res = unsafe { libc::munmap(ptr::invalid_mut(page_size), usize::MAX - 1) };
assert_eq!(res, -1);
assert_eq!(Error::last_os_error().raw_os_error().unwrap(), libc::EINVAL);
}
#[cfg(target_os = "linux")]
fn test_mremap() {
let page_size = page_size::get();
@ -165,5 +277,7 @@ fn test_mremap() {
fn main() {
test_mmap();
#[cfg(target_os = "linux")]
test_mmap64();
#[cfg(target_os = "linux")]
test_mremap();
}