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Fix the alignment of stack entrypoint

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Libc ABI requires 16-byte alignment of the stack entrypoint
This commit is contained in:
LI Qing 2020-11-04 10:38:26 +08:00 committed by Tate, Hongliang Tian
parent 1882458862
commit f87bbc586b
1 changed files with 50 additions and 14 deletions
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64
src/libos/src/process/do_spawn/init_stack.rs
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@ -58,10 +58,11 @@ pub fn do_init(
let stack_buf = unsafe { StackBuf::new(stack_top, init_area_size)? };
let envp_cloned = clone_cstrings_on_stack(&stack_buf, envp)?;
let argv_cloned = clone_cstrings_on_stack(&stack_buf, argv)?;
adjust_alignment(&stack_buf, auxtbl, &envp_cloned, &argv_cloned)?;
dump_auxtbl_on_stack(&stack_buf, auxtbl)?;
dump_cstrptrs_on_stack(&stack_buf, &envp_cloned);
dump_cstrptrs_on_stack(&stack_buf, &argv_cloned);
stack_buf.put(argv.len() as u64);
dump_cstrptrs_on_stack(&stack_buf, &envp_cloned)?;
dump_cstrptrs_on_stack(&stack_buf, &argv_cloned)?;
stack_buf.put(argv.len() as u64)?;
Ok(stack_buf.get_pos())
}
@ -159,21 +160,56 @@ fn clone_cstrings_on_stack<'a, 'b>(
Ok(cstrs_cloned)
}
fn dump_auxtbl_on_stack<'a, 'b>(stack: &'a StackBuf, auxtbl: &'b AuxVec) -> Result<()> {
// For every key-value pair, dump the value first, then the key
stack.put(0 as u64);
stack.put(AuxKey::AT_NULL as u64);
for (aux_key, aux_val) in auxtbl.table() {
stack.put(*aux_val as u64);
stack.put(*aux_key as u64);
fn adjust_alignment(
stack: &StackBuf,
auxtbl: &AuxVec,
envp: &[&CStr],
argv: &[&CStr],
) -> Result<()> {
// Put 8 byte to make the postion of stack 8-byte aligned
stack.put(0 as u64)?;
let current_pos = stack.get_pos();
let to_alloc_size = {
let auxtbl_size = calc_auxtbl_size_on_stack(auxtbl);
let envp_size = calc_cstrptrs_size_on_stack(&envp);
let argv_size = calc_cstrptrs_size_on_stack(&argv);
let argc_size = mem::size_of::<u64>();
auxtbl_size + envp_size + argv_size + argc_size
};
// Libc ABI requires 16-byte alignment of the stack entrypoint.
// Current postion of the stack is 8-byte aligned already, insert 8 byte
// to meet the requirement if necessary.
if (current_pos - to_alloc_size) % 16 != 0 {
stack.put(0 as u64)?;
}
Ok(())
}
fn dump_cstrptrs_on_stack<'a, 'b>(stack: &'a StackBuf, strptrs: &'b [&'a CStr]) -> Result<()> {
stack.put(0 as u64); // End with a NULL pointer
for sp in strptrs.iter().rev() {
stack.put(sp.as_ptr() as u64);
fn dump_auxtbl_on_stack<'a, 'b>(stack: &'a StackBuf, auxtbl: &'b AuxVec) -> Result<()> {
// For every key-value pair, dump the value first, then the key
stack.put(0 as u64)?;
stack.put(AuxKey::AT_NULL as u64)?;
for (aux_key, aux_val) in auxtbl.table() {
stack.put(*aux_val as u64)?;
stack.put(*aux_key as u64)?;
}
Ok(())
}
fn calc_auxtbl_size_on_stack(auxtbl: &AuxVec) -> usize {
let auxtbl_item_size = mem::size_of::<u64>() * 2;
(auxtbl.table().len() + 1) * auxtbl_item_size
}
fn dump_cstrptrs_on_stack<'a, 'b>(stack: &'a StackBuf, strptrs: &'b [&'a CStr]) -> Result<()> {
stack.put(0 as u64)?; // End with a NULL pointer
for sp in strptrs.iter().rev() {
stack.put(sp.as_ptr() as u64)?;
}
Ok(())
}
fn calc_cstrptrs_size_on_stack(strptrs: &[&CStr]) -> usize {
let cstrptrs_item_size = mem::size_of::<u64>();
(strptrs.len() + 1) * cstrptrs_item_size
}