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//! Defines functions and types for crate swapping, used in live evolution and fault recovery.
//!
#![no_std]
#![cfg_attr(loscd_eval, allow(unused_assignments, unused_variables))]
#[macro_use] extern crate alloc;
#[macro_use] extern crate log;
#[macro_use] extern crate lazy_static;
extern crate spin;
extern crate memory;
extern crate hashbrown;
extern crate mod_mgmt;
extern crate fs_node;
extern crate qp_trie;
extern crate path;
extern crate by_address;
#[cfg(loscd_eval)]
extern crate hpet;
use core::{
fmt,
ops::Deref,
};
use alloc::{
borrow::{Cow, ToOwned},
collections::BTreeSet,
string::{String, ToString},
sync::Arc,
vec::Vec,
};
use spin::Mutex;
use hashbrown::HashMap;
use memory::MmiRef;
use fs_node::{FsNode, FileOrDir, FileRef, DirRef};
use mod_mgmt::{
CrateNamespace,
NamespaceDir,
IntoCrateObjectFile,
write_relocation,
crate_name_from_path,
replace_containing_crate_name,
StrongSectionRef,
WeakDependent, StrRef,
};
use path::{Path, PathBuf, Component};
use by_address::ByAddress;
lazy_static! {
/// The set of crates that have been previously unloaded (e.g., swapped out) from a `CrateNamespace`.
/// These are kept in memory as a performance optimization, such that if
/// they are ever requested to be swapped in again, we can swap them back in
/// almost instantly by avoiding the expensive procedure of re-loading them into memory.
///
/// The unloaded cached crates are stored in the form of a CrateNamespace itself,
/// such that we can easily query the cache for crates and symbols by name.
///
/// This is soft state that can be removed at any time with no effect on correctness.
static ref UNLOADED_CRATE_CACHE: Mutex<HashMap<SwapRequestList, CrateNamespace>> = Mutex::new(HashMap::new());
}
/// Clears the cache of unloaded (swapped-out) crates saved from previous crate swapping operations.
pub fn clear_unloaded_crate_cache() {
UNLOADED_CRATE_CACHE.lock().clear();
}
/// A state transfer function is an arbitrary function called when swapping crates.
///
/// See the `swap_crates()` function for more details.
pub type StateTransferFunction = fn(&Arc<CrateNamespace>, &CrateNamespace) -> Result<(), &'static str>;
/// Swaps in new crates that can optionally replace existing crates in this `CrateNamespace`.
///
/// See the documentation of the [`SwapRequest`](#struct.SwapRequest.html) struct for more details.
///
/// In general, the strategy for replacing an old crate `C` with a new crate `C2` consists of three steps:
/// 1) Load the new replacement crate `C2` from its object file.
/// 2) Copy the .data and .bss sections from old crate `C` to the new crate `C2`
/// 3) Set up new relocation entries that redirect all dependencies on the old crate `C` to the new crate `C2`.
/// 4) Remove crate `C` and clean it up, e.g., removing its entries from the symbol map.
/// Save the removed crate (and its symbol subtrie) in a cache for later use to expedite future swapping operations.
///
/// The given `CrateNamespace` is used as the backup namespace for resolving unknown symbols,
/// in adddition to any recursive namespaces on which this namespace depends.
///
/// Upon a successful return, this namespace (and/or its recursive namespace) will have the new crates in place of the old ones,
/// and the old crates will be completely removed from this namespace.
/// In this namespace there will be no remaining dependencies on the old crates,
/// although crates in other namespaces may still include and depend upon those old crates.
///
/// # Arguments
/// * `swap_requests`: a list of several `SwapRequest`s, in order to allow swapping multiple crates all at once
/// as a single "atomic" procedure, which prevents weird linking/relocation errors,
/// such as a new crate linking against an old crate that already exists in this namespace
/// instead of linking against the new one that we want to replace that old crate with.
/// * `override_namespace_dir`: the directories of object files from which missing crates should be loaded.
/// If a crate cannot be found in this directory set, this namespace's directory set will be searched for the crate.
/// If `None`, only this `CrateNamespace`'s directory set (and its recursive namespace's) will be used to find missing crates to be loaded.
/// * `state_transfer_functions`: the fully-qualified symbol names of the state transfer functions,
/// arbitrary functions that are invoked after all of the new crates are loaded but before the old crates are unloaded,
/// in order to allow transfer of states from old crates to new crates or proper setup of states for the new crates.
/// These function should exist in the new namespace (or its directory set) and should take the form of a
/// [`StateTransferFunction`](../type.StateTransferFunction.html).
/// The given functions are invoked with the arguments `(current_namespace, new_namespace)`,
/// in which the `current_namespace` is the one currently running that contains the old crates,
/// and the `new_namespace` contains only newly-loaded crates that are not yet being used.
/// Both namespaces may (and likely will) contain more crates than just the old and new crates specified in the swap request list.
/// * `kernel_mmi_ref`: a reference to the kernel's `MemoryManagementInfo`.
/// * `verbose_log`: enable verbose logging.
///
/// # Warning: Correctness not guaranteed
/// This function currently makes no attempt to guarantee correct operation after a crate is swapped.
/// For example, if the new crate changes a function or data structure, there is no guarantee that
/// other crates will be swapped alongside that one.
/// It will most likely error out, but this responsibility is currently left to the caller.
///
/// # Crate swapping optimizations
/// When one or more crates is swapped out, they are not fully unloaded, but rather saved in a cache
/// in order to accelerate future swapping commands.
///
pub fn swap_crates(
this_namespace: &Arc<CrateNamespace>,
swap_requests: SwapRequestList,
override_namespace_dir: Option<NamespaceDir>,
state_transfer_functions: Vec<String>,
kernel_mmi_ref: &MmiRef,
verbose_log: bool,
cache_old_crates: bool
) -> Result<(), &'static str> {
#[cfg(not(loscd_eval))]
debug!("swap_crates()[0]: \n\t-->override dir: {:?}, \n\t-->cache_old_crates: {:?}, \n\t-->state transfer: {:?},\n\t-->swap_requests: {:?}",
override_namespace_dir.as_ref().map(|d| d.lock().get_name()),
cache_old_crates,
state_transfer_functions,
swap_requests
);
#[cfg(loscd_eval)]
let hpet = hpet::get_hpet().ok_or("couldn't get HPET timer")?;
#[cfg(loscd_eval)]
let hpet_start_swap = hpet.get_counter();
let (namespace_of_new_crates, is_optimized) = {
#[cfg(not(loscd_eval))] {
// First, before we perform any expensive crate loading, let's try an optimization
// based on cached crates that were unloaded during a previous swap operation.
if let Some(previously_cached_crates) = UNLOADED_CRATE_CACHE.lock().remove(&swap_requests) {
warn!("Using optimized swap routine to swap in previously cached crates: {:?}", previously_cached_crates.crate_names(true));
(previously_cached_crates, true)
} else {
// If no optimization is possible (no cached crates exist for this swap request),
// then create a new CrateNamespace and load all of the new crate modules into it from scratch.
let nn = CrateNamespace::new(
String::from("temp_swap"), // format!("temp_swap--{:?}", swap_requests),
// use the optionally-provided directory of crates instead of the current namespace's directories.
override_namespace_dir.unwrap_or_else(|| this_namespace.dir().clone()),
None,
);
// Note that we only need to load the crates that are replacing already-loaded old crates in the old namespace.
let crate_file_iter = swap_requests.iter().filter_map(|swap_req| {
swap_req.old_crate_name.as_deref()
.and_then(|ocn| swap_req.old_namespace.get_crate(ocn))
.map(|_old_loaded_crate| swap_req.new_crate_object_file.deref())
});
nn.load_crates(crate_file_iter, Some(this_namespace), kernel_mmi_ref, verbose_log)?;
(nn, false)
}
}
#[cfg(loscd_eval)] {
let nn = CrateNamespace::new(
String::from("temp_swap"), // format!("temp_swap--{:?}", swap_requests),
// use the optionally-provided directory of crates instead of the current namespace's directories.
override_namespace_dir.unwrap_or_else(|| this_namespace.dir().clone()),
None,
);
// Note that we only need to load the crates that are replacing already-loaded old crates in the old namespace.
let crate_file_iter = swap_requests.iter().filter_map(|swap_req| {
swap_req.old_crate_name.as_deref()
.and_then(|ocn| swap_req.old_namespace.get_crate(ocn))
.map(|_old_loaded_crate| swap_req.new_crate_object_file.deref())
});
nn.load_crates(crate_file_iter, Some(this_namespace), kernel_mmi_ref, verbose_log)?;
(nn, false)
}
};
#[cfg(loscd_eval)]
let hpet_after_load_crates = hpet.get_counter();
#[cfg(not(loscd_eval))]
let (mut future_swap_requests, cached_crates) = if cache_old_crates {
(
SwapRequestList::with_capacity(swap_requests.len()),
CrateNamespace::new(
format!("cached_crates--{swap_requests:?}"),
this_namespace.dir().clone(),
None
),
)
} else {
// When not caching old crates, these won't be used, so just make them empty dummy values.
(SwapRequestList::new(), CrateNamespace::new(String::new(), this_namespace.dir().clone(), None))
};
#[cfg(loscd_eval)]
let mut hpet_total_symbol_finding = 0;
#[cfg(loscd_eval)]
let mut hpet_total_rewriting_relocations = 0;
#[cfg(loscd_eval)]
let mut hpet_total_fixing_dependencies = 0;
#[cfg(loscd_eval)]
let mut hpet_total_bss_transfer = 0;
// The name of the new crate in each swap request. There is one entry per swap request.
let mut new_crate_names: Vec<String> = Vec::with_capacity(swap_requests.len());
// Whether the old crate was actually loaded into the old namespace. There is one entry per swap request.
let mut old_crates_are_loaded: Vec<bool> = Vec::with_capacity(swap_requests.len());
// Now that we have loaded all of the new modules into the new namepsace in isolation,
// we simply need to fix up all of the relocations `WeakDependents` for each of the existing sections
// that depend on the old crate that we're replacing here,
// such that they refer to the new_module instead of the old_crate.
for req in &swap_requests {
let SwapRequest { old_crate_name, old_namespace, new_crate_object_file, new_namespace: _new_ns, reexport_new_symbols_as_old } = req;
let reexport_new_symbols_as_old = *reexport_new_symbols_as_old;
// Populate the list of new crate names for future usage.
let new_crate_name = crate_name_from_path(&PathBuf::from(new_crate_object_file.lock().get_name())).ok_or("invalid crate path")?.to_owned();
new_crate_names.push(new_crate_name.clone());
// Get a reference to the old crate that is currently loaded into the `old_namespace`.
let old_crate_ref = match old_crate_name.as_deref().and_then(|ocn| CrateNamespace::get_crate_and_namespace(old_namespace, ocn)) {
Some((ocr, _ns)) => {
old_crates_are_loaded.push(true);
ocr
}
_ => {
// If the `old_crate_name` was `None`, or the old crate wasn't found, that means it wasn't currently loaded.
// Therefore, we don't need to do any symbol dependency replacement.
// All we need to do is replace that old crate's object file in the old namespace's directory.
if let Some(ref ocn) = old_crate_name {
#[cfg(not(loscd_eval))]
info!("swap_crates(): note: old crate {:?} was not currently loaded into old_namespace {:?}", ocn, old_namespace.name());
}
old_crates_are_loaded.push(false);
continue;
}
};
let old_crate = old_crate_ref.lock_as_mut().ok_or_else(|| {
error!("Unimplemented: swap_crates(), old_crate: {:?}, doesn't yet support deep copying shared crates to get a new exclusive mutable instance", old_crate_ref);
"Unimplemented: swap_crates() doesn't yet support deep copying shared crates to get a new exclusive mutable instance"
})?;
let new_crate_ref = if is_optimized {
debug!("swap_crates(): OPTIMIZED: looking for new crate {:?} in cache", new_crate_name);
namespace_of_new_crates.get_crate(&new_crate_name)
.ok_or("BUG: swap_crates(): Couldn't get new crate from optimized cache")?
} else {
#[cfg(not(loscd_eval))]
debug!("looking for newly-loaded crate {:?} in temp namespace", new_crate_name);
namespace_of_new_crates.get_crate(&new_crate_name)
.ok_or("BUG: Couldn't get new crate that should've just been loaded into a new temporary namespace")?
};
// scope the lock on the `new_crate_ref`
{
let mut new_crate = new_crate_ref.lock_as_mut().ok_or(
"BUG: swap_crates(): new_crate was unexpectedly shared in another namespace (couldn't get as exclusively mutable)...?"
)?;
// currently we're always clearing out the new crate's reexports because we recalculate them every time
new_crate.reexported_symbols.clear();
let old_crate_name_without_hash = String::from(old_crate.crate_name_without_hash());
let new_crate_name_without_hash = String::from(new_crate.crate_name_without_hash());
let crates_have_same_name = old_crate_name_without_hash == new_crate_name_without_hash;
#[cfg(loscd_eval)]
let hpet_start_bss_transfer = hpet.get_counter();
// Go through all the `.data` and `.bss` sections and copy over the old_sec into the new source_sec,
// as they represent static variables that would otherwise result in a loss of data.
for old_sec in old_crate.data_sections_iter() {
let old_sec_name_without_hash = old_sec.name_without_hash();
// get the section from the new crate that corresponds to the `old_sec`
let prefix = if crates_have_same_name {
Cow::from(old_sec_name_without_hash)
} else if let Some(s) = replace_containing_crate_name(old_sec_name_without_hash, &old_crate_name_without_hash, &new_crate_name_without_hash) {
Cow::from(s)
} else {
Cow::from(old_sec_name_without_hash)
};
let new_dest_sec = {
let mut iter = new_crate.data_sections_iter().filter(|sec| sec.name.starts_with(&*prefix));
iter.next()
.filter(|_| iter.next().is_none()) // ensure single element
.ok_or("couldn't find destination section in new crate to copy old_sec's data into (.data/.bss state transfer)")
}?;
#[cfg(not(loscd_eval))]
debug!("swap_crates(): copying .data or .bss section from old {:?} to new {:?}", old_sec, new_dest_sec);
old_sec.copy_section_data_to(new_dest_sec)?;
}
#[cfg(loscd_eval)] {
let hpet_end_bss_transfer = hpet.get_counter();
hpet_total_bss_transfer += hpet_end_bss_transfer - hpet_start_bss_transfer;
}
// We need to find all of the "weak dependents" (sections that depend on the sections in the old crate)
// and replace them by rewriting their relocation entries to point to the corresponding new section in the new_crate.
//
// Note that we only need to iterate through sections from the old crate that are public/global,
// i.e., those that were previously added to this namespace's symbol map,
// because other crates could not possibly depend on non-public sections in the old crate.
for old_sec in old_crate.global_sections_iter() {
#[cfg(not(loscd_eval))]
debug!("swap_crates(): looking for old_sec_name: {:?}", old_sec.name);
let old_sec_ns = this_namespace.get_symbol_and_namespace(&old_sec.name)
.map(|(_weak_sec, ns)| ns)
.ok_or_else(|| {
error!("BUG: swap_crates(): couldn't get old crate's section: {:?}", old_sec.name);
"BUG: swap_crates(): couldn't get old crate's section"
})?;
#[cfg(not(loscd_eval))]
debug!("swap_crates(): old_sec_name: {:?}, old_sec: {:?}", old_sec.name, old_sec);
let old_sec_name_without_hash = old_sec.name_without_hash();
// This closure finds the section in the `new_crate` that corresponds to the given `old_sec` from the `old_crate`.
// And, if enabled, it will reexport that new section under the same name as the `old_sec`.
// We put this procedure in a closure because it's relatively expensive, allowing us to run it only when necessary.
let find_corresponding_new_section = |new_crate_reexported_symbols: &mut BTreeSet<StrRef>| -> Result<StrongSectionRef, &'static str> {
// Use the new namespace to find the new source_sec that old target_sec should point to.
// The new source_sec must have the same name as the old one (old_sec here),
// otherwise it wouldn't be a valid swap -- the target_sec's parent crate should have also been swapped.
// The new namespace should already have that symbol available (i.e., we shouldn't have to load it on demand);
// if not, the swapping action was never going to work and we shouldn't go through with it.
// Find the section in the new crate that matches (or "fuzzily" matches) the current section from the old crate.
let new_crate_source_sec = if crates_have_same_name {
namespace_of_new_crates.get_symbol(&old_sec.name).upgrade()
.or_else(|| namespace_of_new_crates.get_symbol_starting_with(old_sec_name_without_hash).upgrade())
} else {
// here, the crates *don't* have the same name
if let Some(s) = replace_containing_crate_name(old_sec_name_without_hash, &old_crate_name_without_hash, &new_crate_name_without_hash) {
namespace_of_new_crates.get_symbol(&s).upgrade()
.or_else(|| namespace_of_new_crates.get_symbol_starting_with(&s).upgrade())
} else {
// same as the default case above (crates have same name)
namespace_of_new_crates.get_symbol(&old_sec.name).upgrade()
.or_else(|| namespace_of_new_crates.get_symbol_starting_with(old_sec_name_without_hash).upgrade())
}
}.ok_or_else(|| {
error!("swap_crates(): couldn't find section in the new crate that corresponds to a match of the old section {:?}", old_sec.name);
"couldn't find section in the new crate that corresponds to a match of the old section"
})?;
#[cfg(not(loscd_eval))]
debug!("swap_crates(): found match for old source_sec {:?}, new source_sec: {:?}", old_sec, &*new_crate_source_sec);
if reexport_new_symbols_as_old && old_sec.global {
// reexport the new source section under the old sec's name, i.e., redirect the old mapping to the new source sec
let reexported_name = old_sec.name.clone();
new_crate_reexported_symbols.insert(reexported_name.clone());
let _old_val = old_sec_ns.symbol_map().lock().insert(reexported_name, Arc::downgrade(&new_crate_source_sec));
if _old_val.is_none() {
warn!("swap_crates(): reexported new crate section that replaces old section {:?}, but that old section unexpectedly didn't exist in the symbol map", old_sec.name);
}
}
Ok(new_crate_source_sec)
};
// the section from the `new_crate` that corresponds to the `old_sec` from the `old_crate`
let mut new_sec: Option<StrongSectionRef> = None;
// Iterate over all sections that depend on the old_sec.
let mut dead_weak_deps_to_remove: Vec<usize> = Vec::new();
for (i, weak_dep) in old_sec.inner.read().sections_dependent_on_me.iter().enumerate() {
let target_sec = if let Some(sr) = weak_dep.section.upgrade() {
sr
} else {
#[cfg(not(loscd_eval))]
trace!("Removing dead weak dependency on old_sec: {}", old_sec.name);
dead_weak_deps_to_remove.push(i);
continue;
};
let relocation_entry = weak_dep.relocation;
#[cfg(loscd_eval)]
let start_symbol_finding = hpet.get_counter();
// get the section from the new crate that corresponds to the `old_sec`
let new_source_sec = if let Some(ref nsr) = new_sec {
#[cfg(not(loscd_eval))]
trace!("using cached version of new source section");
nsr
} else {
#[cfg(not(loscd_eval))]
trace!("Finding new source section from scratch");
let nsr = find_corresponding_new_section(&mut new_crate.reexported_symbols)?;
new_sec.get_or_insert(nsr)
};
#[cfg(loscd_eval)] {
let end_symbol_finding = hpet.get_counter();
hpet_total_symbol_finding += end_symbol_finding - start_symbol_finding;
}
#[cfg(not(loscd_eval))]
debug!(" swap_crates(): target_sec: {:?}, old source sec: {:?}, new source sec: {:?}", target_sec, old_sec, new_source_sec);
// If the target_sec's mapped pages aren't writable (which is common in the case of swapping),
// then we need to temporarily remap them as writable here so we can fix up the target_sec's new relocation entry.
{
#[cfg(loscd_eval)]
let start_rewriting_relocations = hpet.get_counter();
let mut target_sec_mapped_pages = target_sec.mapped_pages.lock();
let target_sec_initial_flags = target_sec_mapped_pages.flags();
if !target_sec_initial_flags.is_writable() {
target_sec_mapped_pages.remap(&mut kernel_mmi_ref.lock().page_table, target_sec_initial_flags.writable(true))?;
}
write_relocation(
relocation_entry,
target_sec_mapped_pages.as_slice_mut(0, target_sec.mapped_pages_offset + target_sec.size)?,
target_sec.mapped_pages_offset,
new_source_sec.virt_addr,
verbose_log
)?;
#[cfg(loscd_eval)] {
let end_rewriting_relocations = hpet.get_counter();
hpet_total_rewriting_relocations += end_rewriting_relocations - start_rewriting_relocations;
}
#[cfg(not(loscd_eval))] {
// If we temporarily remapped the target_sec's mapped pages as writable, undo that here
if !target_sec_initial_flags.is_writable() {
target_sec_mapped_pages.remap(&mut kernel_mmi_ref.lock().page_table, target_sec_initial_flags)?;
};
}
}
#[cfg(loscd_eval)]
let start_fixing_dependencies = hpet.get_counter();
// Tell the new source_sec that the existing target_sec depends on it.
// Note that we don't need to do this if we're re-swapping in a cached crate,
// because that crate's sections' dependents are already properly set up from when it was first swapped in.
if !is_optimized {
new_source_sec.inner.write().sections_dependent_on_me.push(WeakDependent {
section: Arc::downgrade(&target_sec),
relocation: relocation_entry,
});
}
// Tell the existing target_sec that it no longer depends on the old source section (old_sec),
// and that it now depends on the new source_sec.
let mut found_strong_dependency = false;
for strong_dep in target_sec.inner.write().sections_i_depend_on.iter_mut() {
if Arc::ptr_eq(&strong_dep.section, old_sec) && strong_dep.relocation == relocation_entry {
strong_dep.section = Arc::clone(new_source_sec);
found_strong_dependency = true;
break;
}
}
if !found_strong_dependency {
error!("Couldn't find/remove the existing StrongDependency from target_sec {:?} to old_sec {:?}",
target_sec.name, old_sec.name);
return Err("Couldn't find/remove the target_sec's StrongDependency on the old crate section");
}
#[cfg(loscd_eval)] {
let end_fixing_dependencies = hpet.get_counter();
hpet_total_fixing_dependencies += end_fixing_dependencies - start_fixing_dependencies;
}
} // end of loop that iterates over all weak deps in the old_sec
{
let mut old_sec_inner = old_sec.inner.write();
for index in dead_weak_deps_to_remove {
old_sec_inner.sections_dependent_on_me.remove(index);
}
}
} // end of loop that rewrites dependencies for sections that depend on the old_crate
} // end of scope, drops lock on `new_crate_ref`
} // end of iterating over all swap requests to fix up old crate dependents
// Execute the provided state transfer functions
for symbol in state_transfer_functions {
let state_transfer_fn_sec = namespace_of_new_crates.get_symbol_or_load(&symbol, Some(this_namespace), kernel_mmi_ref, verbose_log).upgrade()
// as a backup, search fuzzily to accommodate state transfer function symbol names without full hashes
.or_else(|| namespace_of_new_crates.get_symbol_starting_with(&symbol).upgrade())
.ok_or("couldn't find specified state transfer function in the new CrateNamespace")?;
// FIXME SAFETY: None. swap_crates should probably be unsafe as there is no guaranteed that the state transfer functions have the correct signature.
let st_fn = unsafe { state_transfer_fn_sec.as_func::<StateTransferFunction>() }?;
#[cfg(not(loscd_eval))]
debug!("swap_crates(): invoking the state transfer function {:?} with old_ns: {:?}, new_ns: {:?}", symbol, this_namespace.name(), namespace_of_new_crates.name());
st_fn(this_namespace, &namespace_of_new_crates)?;
}
// Sanity check that we correctly populated the lists "new_crate_names" and "old_crates_are_loaded".
if swap_requests.len() != new_crate_names.len() && swap_requests.len() != old_crates_are_loaded.len() {
return Err("BUG: swap_crates(): didn't properly populate the list of `new_crate_names` and/or `old_crates_are_loaded`.");
}
// Remove all of the old crates now that we're fully done using them.
// This doesn't mean each crate will be immediately dropped -- they still might be in use by other crates or tasks.
for ((req, new_crate_name), is_old_crate_loaded) in swap_requests.iter().zip(new_crate_names.iter()).zip(old_crates_are_loaded.iter()) {
if !is_old_crate_loaded { continue; }
let SwapRequest { old_crate_name, old_namespace, new_crate_object_file: _, new_namespace, reexport_new_symbols_as_old } = req;
let old_crate_name = match old_crate_name {
Some(ocn) => ocn,
_ => continue,
};
// Remove the old crate from the namespace that it was previously in, and remove its sections' symbols too.
if let Some(old_crate_ref) = old_namespace.crate_tree().lock().remove(old_crate_name.as_bytes()) {
{
let old_crate = old_crate_ref.lock_as_ref();
core::mem::forget(old_crate_ref.clone());
#[cfg(not(loscd_eval))]
info!(" Removed old crate {:?} ({:?}) from namespace {}", old_crate_name, &*old_crate, old_namespace.name());
if cache_old_crates {
#[cfg(not(loscd_eval))]
{
// Here, we setup the crate cache to enable the removed old crate to be quickly swapped back in in the future.
// This removed old crate will be useful when a future swap request includes the following:
// (1) the future `new_crate_object_file` == the current `old_crate.object_file`
// (2) the future `old_crate_name` == the current `new_crate_name`
// (3) the future `reexport_new_symbols_as_old` == true if the old crate had any reexported symbols
// -- to understand this, see the docs for `LoadedCrate.reexported_prefix`
let future_swap_req = SwapRequest {
old_crate_name: Some(new_crate_name.clone()),
old_namespace: ByAddress(Arc::clone(new_namespace)),
new_crate_object_file: ByAddress(old_crate.object_file.clone()),
new_namespace: ByAddress(Arc::clone(old_namespace)),
reexport_new_symbols_as_old: !old_crate.reexported_symbols.is_empty(),
};
future_swap_requests.push(future_swap_req);
}
}
// Remove all of the symbols belonging to the old crate from the namespace it was in.
// If reexport_new_symbols_as_old is true, we MUST NOT remove the old_crate's symbols from this symbol map,
// because we already replaced them above with mappings that redirect to the corresponding new crate sections.
if !reexport_new_symbols_as_old {
let mut old_ns_symbol_map = old_namespace.symbol_map().lock();
for old_sec in old_crate.global_sections_iter() {
if old_ns_symbol_map.remove(&old_sec.name).is_none() {
error!("swap_crates(): couldn't find old symbol {:?} in the old crate's namespace: {}.", old_sec.name, old_namespace.name());
return Err("couldn't find old symbol {:?} in the old crate's namespace");
}
}
}
// If the old crate had reexported its symbols, we should remove those reexports here,
// because they're no longer active since the old crate is being removed.
for sym in &old_crate.reexported_symbols {
let _old_reexported_symbol = old_namespace.symbol_map().lock().remove(sym);
if _old_reexported_symbol.is_none() {
warn!("swap_crates(): the old_crate {:?}'s reexported symbol was not in its old namespace, couldn't be removed.", sym);
}
}
if cache_old_crates {
// TODO: could maybe optimize transfer of old symbols from this namespace to cached_crates namespace
// by saving the removed symbols above and directly adding them to the cached_crates.symbol_map instead of iterating over all old_crate.sections.
// This wil only really be faster once qp_trie supports a non-iterator-based (non-extend) Trie merging function.
#[cfg(not(loscd_eval))]
cached_crates.add_symbols(old_crate.sections.values(), verbose_log);
}
} // drops lock for `old_crate_ref`
if cache_old_crates {
#[cfg(not(loscd_eval))]
cached_crates.crate_tree().lock().insert(old_crate_name.as_str().into(), old_crate_ref);
}
#[cfg(loscd_eval)]
core::mem::forget(old_crate_ref);
}
else {
error!("swap_crates(): couldn't remove old crate {} from old namespace {}!", old_crate_name, old_namespace.name());
continue;
}
}
#[cfg(loscd_eval)]
let start_symbol_cleanup = hpet.get_counter();
// Here, we move all of the new crates into the actual new namespace where they belong.
for ((req, new_crate_name), is_old_crate_loaded) in swap_requests.iter().zip(new_crate_names.iter()).zip(old_crates_are_loaded.iter()) {
// We only expect the new crate to have been loaded into the temp namespace if the old crate was actually loaded in the old namespace
if !is_old_crate_loaded { continue; }
let new_crate_ref = namespace_of_new_crates.crate_tree().lock().remove(new_crate_name.as_bytes())
.ok_or("BUG: swap_crates(): new crate specified by swap request was not found in the new namespace")?;
#[cfg(not(loscd_eval))]
debug!("swap_crates(): adding new crate {:?} to namespace {}", new_crate_ref, req.new_namespace.name());
req.new_namespace.add_symbols(new_crate_ref.lock_as_ref().sections.values(), verbose_log);
req.new_namespace.crate_tree().lock().insert(new_crate_name.as_str().into(), new_crate_ref.clone());
}
// Other crates may have been loaded from their object files into the `namespace_of_new_crates` as dependendencies (required by the new crates specified by swap requests).
// Thus, we need to move all **newly-loaded** crates from the `namespace_of_new_crates` into the proper new namespace;
// for this, we add only the non-shared (exclusive) crates, because shared crates are those that were previously loaded (and came from the backup namespace).
namespace_of_new_crates.for_each_crate(true, |new_crate_name, new_crate_ref| {
if !new_crate_ref.is_shared() {
// TODO FIXME: we may not want to add the new crate to this namespace, we might want to add it to one of its recursive namespaces
// (e.g., `this_namespace` could be an application ns, but the new_crate could be a kernel crate that belongs in `this_namespaces`'s recursive kernel namespace).
//
// To infer which actual namespace this newly-loaded crate should be added to (we don't want to add kernel crates to an application namespace),
// we could iterate over all of the new crates in the swap requests that transitively depend on this new_crate,
// and then look at which `new_namespace` those new crates in the swap requests were destined for.
// Then, we use the highest-level namespace that we can, but it cannot be higher than any one `new_namespace'.
//
// As an example, suppose there are 3 new crates from the swap request list that depend on this new_crate_ref here.
// If two of those were application crates that belong to a higher-level "applications" namespace (their `new_namespace`),
// but one of them was a kernel crate that belonged to a lower "kernel" namespace that was found in that "applications" namespace recursive children,
// the highest-level namespace we could add this `new_crate_ref` to would be that "kernel" namespace,
// meaning that we had inferred that this `new_crate_ref` was also a kernel crate that belonged in the "kernel" namespace.
//
// This follows the rule that crates in a lower-level namespace cannot depend on those in a higher-level namespace.
//
// Note that we don't just want to put the crate in the lowest namespace we can,
// because that could result in putting an application crate in a kernel namespace.
//
let mut target_ns = this_namespace;
// FIXME: currently we use a hack to determine which namespace this freshly-loaded crate should be added to,
// based on which directory its object file
{
let objfile_path = PathBuf::from(new_crate_ref.lock_as_ref().object_file.lock().get_absolute_path());
if objfile_path.components().nth(1) == Some(Component::Normal(mod_mgmt::CrateType::Kernel.default_namespace_name())) {
let new_target_ns = this_namespace.recursive_namespace().unwrap_or(this_namespace);
#[cfg(not(loscd_eval))]
warn!("temp fix: changing target_ns from {} to {}, for crate {:?}", this_namespace.name(), new_target_ns.name(), new_crate_ref);
target_ns = new_target_ns;
}
}
// #[cfg(not(loscd_eval))]
// warn!("swap_crates(): untested scenario of adding new non-requested (dependency) crate {:?} to namespace {}", new_crate_ref, target_ns.name());
target_ns.add_symbols(new_crate_ref.lock_as_ref().sections.values(), verbose_log);
target_ns.crate_tree().lock().insert(new_crate_name.into(), new_crate_ref.clone());
}
else {
#[cfg(not(loscd_eval))] {
if this_namespace.get_crate(new_crate_name).is_none() {
error!("BUG: shared crate {} was not already in the current (backup) namespace", new_crate_name);
}
// else {
// debug!("shared crate {} was in the current namespace like we expected.", new_crate_name);
// }
}
}
true
});
#[cfg(loscd_eval)]
let end_symbol_cleanup = hpet.get_counter();
// Here, we move all of the new crate object files from the temp namespace directory into the namespace directory where they belong,
// and any crate object files that get replaced will be moved to the temp namespace directory.
// This ensures that future usage of the newly swapped-in crates will use the new updated crate object files, not the old ones.
// Effectively, we're swapping the new crate object file with the old.
// Also, since the SwapRequest struct uses direct file references, we don't need to update them when we move the file.
for req in swap_requests.iter() {
let SwapRequest { old_crate_name, old_namespace, new_crate_object_file, new_namespace, reexport_new_symbols_as_old: _ } = req;
let source_dir_ref = new_crate_object_file.lock().get_parent_dir().ok_or("BUG: new_crate_object_file has no parent directory")?;
let dest_dir_ref = new_namespace.dir().deref();
// // If the directories are the same (not overridden), we don't need to do anything.
if Arc::ptr_eq(&source_dir_ref, dest_dir_ref) {
#[cfg(not(loscd_eval))]
trace!("swap_crates(): skipping crate file swap for {:?}", req);
continue;
}
// Move the new crate object file from the temp namespace dir into the namespace dir that it belongs to.
if let Some((mut replaced_old_crate_file, original_source_dir)) = move_file(new_crate_object_file, dest_dir_ref)? {
// If we replaced a crate object file, put that replaced file back in the source directory, thus completing the "swap" operation.
// (Note that the file that we replaced should be the same as the old_crate_file.)
#[cfg(not(loscd_eval))]
trace!("swap_crates(): new_crate_object_file replaced existing (old_crate) object file {:?}", replaced_old_crate_file.get_name());
replaced_old_crate_file.set_parent_dir(Arc::downgrade(&original_source_dir));
if let Some(_f) = original_source_dir.lock().insert(replaced_old_crate_file)? {
// There shouldn't be a similarly-named file in the original source dir anymore, since we moved it.
// However, this isn't necessarily a real problem; we can continue execution, but I'd like to log an error for sanity checking purposes.
error!("swap_crates(): unexpectedly replaced file {:?} that was in source directory {:?}", _f.get_name(), original_source_dir.lock().get_absolute_path());
}
} else {
// If inserting the new crate object file didn't end up replacing the existing crate object file (the old_crate's object file),
// then we need to remove the old_crate's object file here, if one was specified.
if let Some(ocn) = old_crate_name {
#[cfg(not(loscd_eval))]
trace!("swap_crates(): new_crate_object_file did not replace old_crate's object file, so we're removing the old_crate's object file now");
let (old_crate_object_file, _old_ns) = CrateNamespace::get_crate_object_file_starting_with(old_namespace, ocn).ok_or_else(|| {
error!("BUG: swap_crates(): couldn't find old crate's object file starting with {:?} in old namespace {:?}.", ocn, old_namespace.name());
"BUG: swap_crates(): couldn't find old crate's object file in old namespace!"
})?;
let mut removed_old_crate_file = old_namespace.dir().lock().remove(&FileOrDir::File(Arc::clone(&old_crate_object_file))).ok_or_else(|| {
error!("BUG: swap_crates(): couldn't remove old crate's object file {:?} from old namespace {:?}.", old_crate_object_file.lock().get_name(), old_namespace.name());
"BUG: swap_crates(): couldn't remove old crate's object file from old namespace!"
})?;
removed_old_crate_file.set_parent_dir(Arc::downgrade(&source_dir_ref));
if let Some(_f) = source_dir_ref.lock().insert(removed_old_crate_file)? {
// This is not necessarily a problem, but is currently unexpected behavior.
warn!("swap_crates(): unexpectedly replaced file {:?} that was in source directory {:?}", _f.get_name(), source_dir_ref.lock().get_absolute_path());
}
} else {
// If there's no old crate to be replaced (we're just adding a new crate), then we don't need to do anything here.
}
}
}
if cache_old_crates {
#[cfg(not(loscd_eval))]
{
debug!("swap_crates() [end]: adding old_crates to cache. \n future_swap_requests: {:?}, \n old_crates: {:?}",
future_swap_requests, cached_crates.crate_names(true));
UNLOADED_CRATE_CACHE.lock().insert(future_swap_requests, cached_crates);
}
}
#[cfg(loscd_eval)] {
// done with everything, print out values
warn!("Measured time in units of HPET ticks:
load crates, {}
find symbols, {}
rewrite relocations, {}
fix dependencies, {}
BSS transfer, {}
symbol cleanup, {}
HPET PERIOD (femtosec): {}
",
hpet_after_load_crates - hpet_start_swap,
hpet_total_symbol_finding,
hpet_total_rewriting_relocations,
hpet_total_fixing_dependencies,
hpet_total_bss_transfer,
end_symbol_cleanup - start_symbol_cleanup,
hpet.counter_period_femtoseconds(),
);
}
Ok(())
// here, "namespace_of_new_crates is dropped, but its crates have already been added to the current namespace
}
/// Convenience function that removes the given `file` from its parent directory
/// and inserts it into the given destination directory.
///
/// # Return
/// If the file ends up replacing a file/dir node in the `dest_dir`, this returns a tuple of:
/// 1. The node that was in the `dest_dir` that got replaced by the given `file`,
/// 2. The parent directory that originally contained the given `file`. This is useful for realizing a file "swap" operation.
///
/// # Locking / Deadlock
/// This function obtains the lock on both `file`, the `file`'s parent directory, and the `dest_dir`.
fn move_file(file: &FileRef, dest_dir: &DirRef) -> Result<Option<(FileOrDir, DirRef)>, &'static str> {
let parent = file.lock().get_parent_dir().ok_or("couldn't get file's parent directory")?;
// This section is redundent as it is checked before calling the function
// if Arc::ptr_eq(&parent, dest_dir) {
// trace!("swap_crates::move_file(): skipping move between same directory {:?} for file {:?}",
// dest_dir.try_lock().map(|f| f.get_absolute_path()), file.try_lock().map(|f| f.get_absolute_path())
// );
// return Ok(None);
// }
// Perform the actual move operation.
let mut removed_file = parent.lock().remove(&FileOrDir::File(Arc::clone(file))).ok_or("Couldn't remove file from its parent directory")?;
removed_file.set_parent_dir(Arc::downgrade(dest_dir));
let res = dest_dir.lock().insert(removed_file.clone());
// Log success or failure
match res {
Ok(replaced_file) => {
#[cfg(not(loscd_eval))]
debug!("swap_crates::move_file(): moved file {:?} ({:?}) from {:?} to {:?}",
file.try_lock().map(|f| f.get_name()), removed_file.get_name(), parent.try_lock().map(|p| p.get_name()), dest_dir.try_lock().map(|d| d.get_name())
);
Ok(replaced_file.map(|f| (f, parent)))
}
Err(e) => {
#[cfg(not(loscd_eval))]
error!("swap_crates::move_file(): failed to moved file {:?} ({:?}) from {:?} to {:?}.\n Error: {:?}",
file.try_lock().map(|f| f.get_name()), removed_file.get_name(), parent.try_lock().map(|p| p.get_name()), dest_dir.try_lock().map(|d| d.get_name()), e
);
Err(e)
}
}
}
/// A list of one or more `SwapRequest`s that is used by the `swap_crates` function.
pub type SwapRequestList = Vec<SwapRequest>;
/// This struct is used to specify the details of a crate-swapping operation,
/// in which an "old" crate is replaced with a "new" crate that is then used in place of that old crate.
/// The old crate is removed from its old `CrateNamespace` while the new crate
/// is added to the new `CrateNamespace`; typically the old and new namespaces are the same.
///
/// # Important Note: Reexporting Symbols
/// When swapping out an old crate, the new crate must satisfy all of the dependencies
/// that other crates had on that old crate.
/// However, the swapping procedure will completely remove the old crate and its symbols from its containing `CrateNamespace`,
/// so it may be useful to re-expose or "mirror" the new crate's sections as symbols with names
/// that match the relevant sections from the old crate.
/// This satisfies other crates' dependenices on the old crate while allowing the new crate to exist normally,
/// which means that the new crate's symbols appear both as those from the new crate itself
/// in addition to those from the old crate that was replaced.
/// To do this, set the `reexport_new_symbols_as_old` option to `true`.
///
/// However, **enabling this option is potentially dangerous**, as you must take responsibility
/// for ensuring that the new crate can safely and correctly replace the old crate,
/// and that using the new crate in place of the old crate will not break any other dependent crates.
/// This will necessarily ignore the hashes when matching symbols across the old and new crate,
/// and hashes are how Theseus ensures that different crates and functions are linked to the correct version of each other.
/// However, this does make the swapping operation much simpler to use,
/// because you will likely need to swap far fewer crates at once,
/// and as a convenience bonus, you don't have to specify the exact versions (hashes) of each crate.
///
/// ## Example of Reexporting Symbols
/// There exists a function `drivers::init::h...` in the `drivers` crate
/// that depends on the function `keyboard::init::hABC` in the `keyboard` crate.
/// We call `swap_crates()` to replace the `keyboard` crate with a new crate called `keyboard_new`.
///
/// If `reexport_new_symbols_as_old` is `true`, the new `keyboard_new` crate's function called `keyboard_new::init::hDEF`
/// will now appear in the namespace's symbol map twice:
/// 1. in its normal form `keyboard_new::init::hDEF`, which is the normal behavior when loading a crate, and
/// 2. in its reexported form `keyboard::init::hABC`, which exactly matches the function from the old `keyboard` crate.
///
/// In this way, the single function in the new crate `keyboard_new` appears twice in the symbol map
/// under different names, allowing it to fulfill dependencies on both the old crate and the new crate.
/// In general, this option is not needed.
///
#[derive(Eq, PartialEq, Hash)]
pub struct SwapRequest {
// Note: the usage of `ByAddress` is to allow us to hash and compare reference types like Arc
// to make sure that they point to the same file rather than having the same actual contents.
// It makes hashing extremely cheap and fast!
/// The full name of the old crate that will be replaced by the new crate.
/// This will be used to search the `CrateNamespace` to find an existing `LoadedCrate`.
/// The `SwapRequest` constructor ensures this is fully-qualified (includes a hash value)
/// and is unique within the `old_namespace`.
old_crate_name: Option<String>,
/// The `CrateNamespace` that contains the given old crate,
/// from which that old crate and its symbols should be removed.
old_namespace: ByAddress<Arc<CrateNamespace>>,
/// The object file for the new crate that will replace the old crate.
new_crate_object_file: ByAddress<FileRef>,
/// The `CrateNamespace` into which the replacement new crate and its symbols should be loaded.
/// Typically, this is the same namespace as the `old_namespace`.
new_namespace: ByAddress<Arc<CrateNamespace>>,
/// Whether to expose the new crate's sections with symbol names that match those from the old crate.
/// For more details, see the above docs for this struct.
reexport_new_symbols_as_old: bool,
}
impl fmt::Debug for SwapRequest {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("SwapRequest")
.field("old_crate", &self.old_crate_name)
.field("old_namespace", &self.old_namespace.name())
.field("new_crate", &self.new_crate_object_file.try_lock()
.map(|f| f.get_absolute_path())
.unwrap_or_else(|| "<Locked>".to_string())
)
.field("new_namespace", &self.new_namespace.name())
.field("reexport_symbols", &self.reexport_new_symbols_as_old)
.finish()
}
}
impl SwapRequest {
/// Create a new `SwapRequest` that, when given to `swap_crates()`,
/// will swap out the given old crate and replace it with the given new crate,
/// and optionally re-export the new crate's symbols.
///
/// # Arguments
/// * `old_crate_name`: the name of the old crate that should be unloaded and removed from the `old_namespace`.
/// An `old_crate_name` of `None` (or an empty string) signifies there is no old crate to be removed,
/// and that only a new crate will be added.
///
/// Note that `old_crate_name` can be any string prefix, so long as it can uniquely identify a crate object file
/// in the given `old_namespace` or any of its recursive namespaces.
/// Thus, to be more accurate, it is wise to specify a full crate name with hash, e.g., `"my_crate-<hash>"`.
///
/// * `old_namespace`: the `CrateNamespace` that contains the old crate;
/// that old crate and its symbols will be removed from this namespace.
///
/// If `old_crate_name` is `None`, then `old_namespace` should be the same namespace
/// as the `this_namespace` argument that `swap_crates()` is invoked with.
///
/// * `new_crate_object_file`: a type that can be converted into a crate object file.
/// This can either be a direct reference to the file, an absolute `PathBuf` that points to the file,
/// or a prefix string used to find the file in the new namespace's directory of crate object files.
///
/// * `new_namespace`: the `CrateNamespace` to which the new crate will be loaded and its symbols added.
/// If `None`, then the new crate will be loaded into the `old_namespace`, which is a common case for swapping.
///
/// * `reexport_new_symbols_as_old`: if `true`, all public symbols the new crate will be reexported
/// in the `new_namespace` with the same full name those symbols had from the old crate in the `old_namespace`.
/// See the "Important Note" in the struct-level documentation for more details.
///
pub fn new(
// We could change this to `Option<&str>`
old_crate_name: Option<&str>,
old_namespace: Arc<CrateNamespace>,
new_crate_object_file: IntoCrateObjectFile,
new_namespace: Option<Arc<CrateNamespace>>,
reexport_new_symbols_as_old: bool,
) -> Result<SwapRequest, InvalidSwapRequest> {
// Check that the old crate is actually in the old namespace;
// it may be currently loaded into the old namespace,
// but if not, we look to see if its crate object file is there.
let (old_crate_full_name, real_old_namespace) = match old_crate_name {
None | Some("") => {
// If the old crate name is empty, that means there is no old crate to replace.
(None, &old_namespace)
}
Some(ocn) => {
// Look for a single loaded crate that matches the `old_crate_name` prefix.
let mut matching_crates = CrateNamespace::get_crates_starting_with(&old_namespace, ocn);
if matching_crates.len() == 1 {
let (old_crate_full_name, _ocr, real_old_namespace) = matching_crates.remove(0);
(Some(old_crate_full_name.to_string()), real_old_namespace)
} else {
// If we couldn't find a single loaded crate, then the old crate may not be loaded yet.
// Thus, we should instead look for a single crate **object file** that matches the `old_crate_name` prefix.
let mut matching_files = CrateNamespace::get_crate_object_files_starting_with(&old_namespace, ocn);
if matching_files.len() == 1 {
let (old_crate_file, real_old_namespace) = matching_files.remove(0);
let old_crate_file_path = PathBuf::from(old_crate_file.lock().get_name());
let old_crate_full_name = crate_name_from_path(&old_crate_file_path)
.ok_or(InvalidSwapRequest::OldCrateNotFound(old_crate_name.map(|name| name.to_owned()), old_namespace.clone(), Vec::new()))?
.into();
(Some(old_crate_full_name), real_old_namespace)
} else {
// Here, we couldn't find a single matching loaded crate or crate object file, so we return an error.
let matches_vec = if !matching_crates.is_empty() {
matching_crates.into_iter().map(|(c_name, _c_ref, ns)| (c_name.to_string(), Arc::clone(ns))).collect::<Vec<_>>()
} else if !matching_files.is_empty() {
matching_files.into_iter()
.map(|(file, ns)| (
file.try_lock().map(|f| f.get_absolute_path()).unwrap_or_else(|| "<Locked>".to_string()),
Arc::clone(ns)
))
.collect::<Vec<_>>()
} else {
Vec::new()
};
return Err(InvalidSwapRequest::OldCrateNotFound(
old_crate_name.map(ToString::to_string),
old_namespace,
matches_vec,
));
}
}
}
};
if !Arc::ptr_eq(&old_namespace, real_old_namespace) {
trace!("SwapRequest::new(): changing old namespace from {:?} to {:?}", old_namespace.name(), real_old_namespace.name());
}
// If no new namespace was given, use the same namespace that the old crate was found in.
let mut new_namespace = new_namespace.unwrap_or_else(|| {
trace!("SwapRequest::new(): new namespace was None, using old namespace {:?}", real_old_namespace.name());
Arc::clone(real_old_namespace)
});
// Try to resolve the new crate argument into an actual file.
let verified_new_crate_file = match new_crate_object_file {
IntoCrateObjectFile::File(f) => f,
IntoCrateObjectFile::AbsolutePath(path) => match Path::get_absolute(&path) {
Some(FileOrDir::File(f)) => f,
_ => if path.is_absolute() {
return Err(InvalidSwapRequest::NewCrateAbsolutePathNotFound(path));
} else {
return Err(InvalidSwapRequest::NewCratePathBufNotAbsolute(path));
},
}
IntoCrateObjectFile::Prefix(prefix) => {
let (new_crate_file, real_new_namespace) = {
let mut matching_files = CrateNamespace::get_crate_object_files_starting_with(&new_namespace, &prefix);
if matching_files.len() == 1 {
matching_files.remove(0)
} else {
return Err(InvalidSwapRequest::NewCratePrefixNotFound(
prefix,
Arc::clone(&new_namespace),
matching_files.into_iter().map(|(f, ns_ref)| (f, Arc::clone(ns_ref))).collect::<Vec<_>>()
));
}
};
if !Arc::ptr_eq(&new_namespace, real_new_namespace) {
trace!("SwapRequest::new(): changing new namespace from {:?} to {:?}", new_namespace.name(), real_new_namespace.name());
new_namespace = Arc::clone(real_new_namespace);
}
new_crate_file
}
};
Ok(SwapRequest {
old_crate_name: old_crate_full_name,
old_namespace: ByAddress(Arc::clone(real_old_namespace)),
new_crate_object_file: ByAddress(verified_new_crate_file),
new_namespace: ByAddress(new_namespace),
reexport_new_symbols_as_old,
})
}
}
/// The possible errors that can occur when trying to create a valid `SwapRequest`.
pub enum InvalidSwapRequest {
/// The old crate was not found in the old `CrateNamespace`.
/// The enclosed `String` is the `old_crate_name` passed into `SwapRequest::new()`.
/// The enclosed vector is the list of matching crate names or crate object file names
/// along with the `CrateNamespace` in which they were found.
OldCrateNotFound(Option<String>, Arc<CrateNamespace>, Vec<(String, Arc<CrateNamespace>)>),
/// The given absolute `PathBuf` for the new crate object file could not be resolved.
NewCrateAbsolutePathNotFound(PathBuf),
/// The given `PathBuf` for the new crate object file was not an absolute path, as expected.
NewCratePathBufNotAbsolute(PathBuf),
/// A single crate object file could not be found by matching the given prefix `String`
/// within the given new `CrateNamespace` (which was searched recursively).
/// Either zero or multiple crate object files matched the prefix,
/// the results of the match are given by the enclosed vector.
NewCratePrefixNotFound(String, Arc<CrateNamespace>, Vec<(FileRef, Arc<CrateNamespace>)>),
}
impl fmt::Debug for InvalidSwapRequest {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let mut dbg = f.debug_struct("InvalidSwapRequest");
match self {
Self::OldCrateNotFound(old_crate_name, old_namespace, matches) => {
if matches.is_empty() {
dbg.field("reason", &"No Matches for Old Crate Name");
} else {
dbg.field("reason", &"Multiple Matches for Old Crate Name");
}
dbg.field("old_crate_name", old_crate_name)
.field("old_namespace", &old_namespace.name());
for (f, ns) in matches {
dbg.field("match", &format!("{:?} in namespace {:?}", f, ns.name()));
}
}
Self::NewCrateAbsolutePathNotFound(path) => {
dbg.field("reason", &"New Crate Absolute PathBuf Not Found")
.field("path", &path);
}
Self::NewCratePathBufNotAbsolute(path) => {
dbg.field("reason", &"New Crate PathBuf Not Absolute")
.field("path", &path);
}
Self::NewCratePrefixNotFound(prefix, new_namespace, matches) => {
if matches.is_empty() {
dbg.field("reason", &"No Matches for New Crate File Prefix");
} else {
dbg.field("reason", &"Multiple Matches for New Crate File Prefix");
}
dbg.field("prefix", &prefix)
.field("searched in new_namespace", &new_namespace.name());
for (file, ns) in matches {
let s = format!("{:?} in namespace {:?}",
file.try_lock().map(|f| f.get_absolute_path()).unwrap_or_else(|| "<Locked>".to_string()),
ns.name(),
);
dbg.field("matching file", &s);
}
}
};
dbg.finish()
}
}