vasilito/RedBear-OS
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

redox-rt: Use non-fixed and anonymous remote mmap

Browse Source
This commit is contained in:
bjorn3
2025-12-09 20:56:56 +01:00
parent 02f6dd3faf
commit 0158b111e0
2 changed files with 48 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files
redox-rt/src/proc.rs
+48 -55
View File
@@ -68,7 +68,6 @@ pub fn fexec_impl(
image_file: FdGuardUpper,
thread_fd: &FdGuardUpper,
proc_fd: &FdGuardUpper,
memory_scheme_fd: &FdGuardUpper,
path: &[u8],
args: &[&[u8]],
envs: &[&[u8]],
@@ -161,12 +160,12 @@ pub fn fexec_impl(
return Err(Error::new(ENOEXEC));
}
allocate_remote(
mmap_anon_remote(
&grants_fd,
memory_scheme_fd,
0,
vaddr,
total_page_count * PAGE_SIZE,
flags,
flags | MapFlags::MAP_FIXED_NOREPLACE,
)?;
// TODO: Attempt to mmap with MAP_PRIVATE directly from the image file instead.
@@ -202,12 +201,12 @@ pub fn fexec_impl(
}
}
allocate_remote(
mmap_anon_remote(
&grants_fd,
memory_scheme_fd,
0,
STACK_TOP - STACK_SIZE,
STACK_SIZE,
MapFlags::PROT_READ | MapFlags::PROT_WRITE,
MapFlags::PROT_READ | MapFlags::PROT_WRITE | MapFlags::MAP_FIXED_NOREPLACE,
)?;
tree.insert(STACK_TOP - STACK_SIZE, STACK_SIZE);
@@ -258,15 +257,14 @@ pub fn fexec_impl(
&*phs_raw
};
let pheaders_size_aligned = pheaders_to_convey.len().next_multiple_of(PAGE_SIZE);
let pheaders = find_free_target_addr(&tree, pheaders_size_aligned).ok_or(Error::new(ENOMEM))?;
tree.insert(pheaders, pheaders_size_aligned);
allocate_remote(
let pheaders = mmap_anon_remote(
&grants_fd,
memory_scheme_fd,
pheaders,
0,
0,
pheaders_size_aligned,
MapFlags::PROT_READ | MapFlags::PROT_WRITE,
)?;
tree.insert(pheaders, pheaders_size_aligned);
unsafe {
let (_guard, memory) =
MmapGuard::map_mut_anywhere(&grants_fd, pheaders, pheaders_size_aligned)?;
@@ -307,12 +305,10 @@ pub fn fexec_impl(
+ envs.iter().map(|env| env.len() + 1).sum::<usize>()
+ extrainfo.cwd.map_or(0, |s| s.len() + 1);
let args_envs_size_aligned = total_args_envs_auxvpointee_size.next_multiple_of(PAGE_SIZE);
let target_args_env_address =
find_free_target_addr(&tree, args_envs_size_aligned).ok_or(Error::new(ENOMEM))?;
allocate_remote(
let target_args_env_address = mmap_anon_remote(
&grants_fd,
memory_scheme_fd,
target_args_env_address,
0,
0,
args_envs_size_aligned,
MapFlags::PROT_READ | MapFlags::PROT_WRITE,
)?;
@@ -474,18 +470,8 @@ pub fn fexec_impl(
unreachable!();
}
fn write_usizes<const N: usize>(fd: &FdGuardUpper, usizes: [usize; N]) -> Result<()> {
fd.write(unsafe { plain::as_bytes(&usizes) })?;
Ok(())
}
fn allocate_remote(
addrspace_fd: &FdGuardUpper,
memory_scheme_fd: &FdGuardUpper,
dst_addr: usize,
len: usize,
flags: MapFlags,
) -> Result<()> {
mmap_remote(addrspace_fd, memory_scheme_fd, 0, dst_addr, len, flags)
fn write_usizes<const N: usize>(fd: &FdGuardUpper, usizes: [usize; N]) -> Result<usize> {
fd.write(unsafe { plain::as_bytes(&usizes) })
}
pub fn mmap_remote(
addrspace_fd: &FdGuardUpper,
@@ -494,7 +480,7 @@ pub fn mmap_remote(
dst_addr: usize,
len: usize,
flags: MapFlags,
) -> Result<()> {
) -> Result<usize> {
write_usizes(
addrspace_fd,
[
@@ -509,7 +495,32 @@ pub fn mmap_remote(
// size
len,
// flags
(flags | MapFlags::MAP_FIXED_NOREPLACE).bits(),
flags.bits(),
],
)
}
pub fn mmap_anon_remote(
addrspace_fd: &FdGuardUpper,
offset: usize,
dst_addr: usize,
len: usize,
flags: MapFlags,
) -> Result<usize> {
write_usizes(
addrspace_fd,
[
// op
syscall::flag::ADDRSPACE_OP_MMAP,
// fd
!0,
// "offset"
offset,
// address
dst_addr,
// size
len,
// flags
flags.bits(),
],
)
}
@@ -531,7 +542,8 @@ pub fn mprotect_remote(
// flags
flags.bits(),
],
)
)?;
Ok(())
}
pub fn munmap_remote(addrspace_fd: &FdGuardUpper, addr: usize, len: usize) -> Result<()> {
write_usizes(
@@ -544,7 +556,8 @@ pub fn munmap_remote(addrspace_fd: &FdGuardUpper, addr: usize, len: usize) -> Re
// size
len,
],
)
)?;
Ok(())
}
pub fn munmap_transfer(
src: &FdGuardUpper,
@@ -570,7 +583,8 @@ pub fn munmap_transfer(
// flags
(flags | MapFlags::MAP_FIXED_NOREPLACE).bits(),
],
)
)?;
Ok(())
}
fn pread_all(fd: &FdGuardUpper, offset: u64, buf: &mut [u8]) -> Result<()> {
fd.lseek(offset as isize, SEEK_SET)?;
@@ -586,27 +600,6 @@ fn pread_all(fd: &FdGuardUpper, offset: u64, buf: &mut [u8]) -> Result<()> {
Ok(())
}
// TODO: With the introduction of remote mmaps, remove this and let the kernel handle address
// allocation.
fn find_free_target_addr(tree: &BTreeMap<usize, usize>, size: usize) -> Option<usize> {
let mut iterator = tree.iter().peekable();
// Ignore the space between zero and the first region, to avoid null pointers.
while let Some((cur_address, entry_size)) = iterator.next() {
let end = *cur_address + entry_size;
if let Some((next_address, _)) = iterator.peek() {
if **next_address - end > size {
return Some(end);
}
}
// No need to check last entry, since the stack will always be put at the highest
// possible address.
}
None
}
pub struct MmapGuard<'a> {
fd: &'a FdGuardUpper,
base: usize,
src/platform/redox/exec.rs
-4
View File
@@ -29,8 +29,6 @@ fn fexec_impl(
extrainfo: &ExtraInfo,
interp_override: Option<InterpOverride>,
) -> Result<Infallible> {
let memory = FdGuard::open("/scheme/memory", O_CLOEXEC)?.to_upper()?;
let FexecResult::Interp {
image_file,
path,
@@ -39,7 +37,6 @@ fn fexec_impl(
exec_file,
&RtTcb::current().thread_fd(),
redox_rt::current_proc_fd(),
&memory,
path,
args,
envs,
@@ -48,7 +45,6 @@ fn fexec_impl(
)?;
drop(image_file);
drop(memory);
// According to elf(5), PT_INTERP requires that the interpreter path be
// null-terminated. Violating this should therefore give the "format error" ENOEXEC.