InvokeContext: Add get_sysvar() helper to sdk (backport #17360) (#17368)

* Add get_sysvar() helper to sdk

(cherry picked from commit 2c99b23ad7)

# Conflicts:
#	runtime/src/message_processor.rs
#	sdk/src/process_instruction.rs

* Resolve conflicts

Co-authored-by: Michael Vines <mvines@gmail.com>

programs/bpf_loader/src/syscalls.rs

@@ -29,7 +29,7 @@ use solana_sdk::{
     keccak,
     keyed_account::KeyedAccount,
     native_loader,
-    process_instruction::{stable_log, ComputeMeter, InvokeContext, Logger},
+    process_instruction::{self, stable_log, ComputeMeter, InvokeContext, Logger},
     pubkey::{Pubkey, PubkeyError, MAX_SEEDS},
     rent::Rent,
     sysvar::{self, fees::Fees, Sysvar, SysvarId},
@@ -960,8 +960,8 @@ fn get_sysvar<T: std::fmt::Debug + Sysvar + SysvarId>(
     memory_mapping: &MemoryMapping,
     invoke_context: Rc<RefCell<&mut dyn InvokeContext>>,
 ) -> Result<u64, EbpfError<BpfError>> {
-    let mut invoke_context = invoke_context
-        .try_borrow_mut()
+    let invoke_context = invoke_context
+        .try_borrow()
         .map_err(|_| SyscallError::InvokeContextBorrowFailed)?;
 
     invoke_context.get_compute_meter().consume(
@@ -974,15 +974,8 @@ fn get_sysvar<T: std::fmt::Debug + Sysvar + SysvarId>(
         invoke_context.is_feature_active(&enforce_aligned_host_addrs::id()),
     )?;
 
-    let sysvar_data = invoke_context.get_sysvar_data(id).ok_or_else(|| {
-        ic_msg!(invoke_context, "Unable to get Sysvar {}", id);
-        SyscallError::InstructionError(InstructionError::UnsupportedSysvar)
-    })?;
-
-    *var = bincode::deserialize(&sysvar_data).map_err(|e| {
-        ic_msg!(invoke_context, "Unable to get Sysvar {}: {:?}", id, e);
-        SyscallError::InstructionError(InstructionError::UnsupportedSysvar)
-    })?;
+    *var = process_instruction::get_sysvar::<T>(*invoke_context, id)
+        .map_err(SyscallError::InstructionError)?;
 
     Ok(SUCCESS)
 }

runtime/src/message_processor.rs

@@ -270,7 +270,8 @@ pub struct ThisInvokeContext<'a> {
     pub timings: ExecuteDetailsTimings,
     account_db: Arc<Accounts>,
     ancestors: &'a Ancestors,
-    sysvars: Vec<(Pubkey, Option<Rc<Vec<u8>>>)>,
+    #[allow(clippy::type_complexity)]
+    sysvars: RefCell<Vec<(Pubkey, Option<Rc<Vec<u8>>>)>>,
 }
 impl<'a> ThisInvokeContext<'a> {
     #[allow(clippy::too_many_arguments)]
@@ -309,7 +310,7 @@ impl<'a> ThisInvokeContext<'a> {
             timings: ExecuteDetailsTimings::default(),
             account_db,
             ancestors,
-            sysvars: vec![],
+            sysvars: RefCell::new(vec![]),
         }
     }
 }
@@ -429,10 +430,10 @@ impl<'a> InvokeContext for ThisInvokeContext<'a> {
         self.timings.execute_us += execute_us;
         self.timings.deserialize_us += deserialize_us;
     }
-    fn get_sysvar_data(&mut self, id: &Pubkey) -> Option<Rc<Vec<u8>>> {
+    fn get_sysvar_data(&self, id: &Pubkey) -> Option<Rc<Vec<u8>>> {
+        if let Ok(mut sysvars) = self.sysvars.try_borrow_mut() {
             // Try share from cache
-        let mut result =
-            self.sysvars
+            let mut result = sysvars
                 .iter()
                 .find_map(|(key, sysvar)| if id == key { sysvar.clone() } else { None });
             if result.is_none() {
@@ -442,9 +443,12 @@ impl<'a> InvokeContext for ThisInvokeContext<'a> {
                     .load_slow(self.ancestors, id)
                     .map(|(account, _)| Rc::new(account.data().clone()));
                 // Cache it
-            self.sysvars.push((*id, result.clone()));
+                sysvars.push((*id, result.clone()));
             }
             result
+        } else {
+            None
+        }
     }
 }
 pub struct ThisLogger {

sdk/src/process_instruction.rs

@@ -4,6 +4,7 @@ use solana_sdk::{
     keyed_account::KeyedAccount,
     message::Message,
     pubkey::Pubkey,
+    sysvar::Sysvar,
 };
 use std::{cell::RefCell, fmt::Debug, rc::Rc, sync::Arc};
 
@@ -69,7 +70,7 @@ pub trait InvokeContext {
         deserialize_us: u64,
     );
     /// Get sysvar data
-    fn get_sysvar_data(&mut self, id: &Pubkey) -> Option<Rc<Vec<u8>>>;
+    fn get_sysvar_data(&self, id: &Pubkey) -> Option<Rc<Vec<u8>>>;
 }
 
 /// Convenience macro to log a message with an `Rc<RefCell<dyn Logger>>`
@@ -102,6 +103,21 @@ macro_rules! ic_msg {
     };
 }
 
+pub fn get_sysvar<T: Sysvar>(
+    invoke_context: &dyn InvokeContext,
+    id: &Pubkey,
+) -> Result<T, InstructionError> {
+    let sysvar_data = invoke_context.get_sysvar_data(id).ok_or_else(|| {
+        ic_msg!(invoke_context, "Unable to get sysvar {}", id);
+        InstructionError::UnsupportedSysvar
+    })?;
+
+    bincode::deserialize(&sysvar_data).map_err(|err| {
+        ic_msg!(invoke_context, "Unable to get sysvar {}: {:?}", id, err);
+        InstructionError::UnsupportedSysvar
+    })
+}
+
 #[derive(Clone, Copy, Debug, AbiExample)]
 pub struct BpfComputeBudget {
     /// Number of compute units that an instruction is allowed.  Compute units
@@ -302,6 +318,22 @@ impl Default for MockInvokeContext {
         }
     }
 }
+
+pub fn mock_set_sysvar<T: Sysvar>(
+    mock_invoke_context: &mut MockInvokeContext,
+    id: Pubkey,
+    sysvar: T,
+) -> Result<(), InstructionError> {
+    let mut data = Vec::with_capacity(T::size_of());
+
+    bincode::serialize_into(&mut data, &sysvar).map_err(|err| {
+        ic_msg!(mock_invoke_context, "Unable to serialize sysvar: {:?}", err);
+        InstructionError::GenericError
+    })?;
+    mock_invoke_context.sysvars.push((id, Some(Rc::new(data))));
+    Ok(())
+}
+
 impl InvokeContext for MockInvokeContext {
     fn push(&mut self, _key: &Pubkey) -> Result<(), InstructionError> {
         self.invoke_depth = self.invoke_depth.saturating_add(1);
@@ -361,7 +393,7 @@ impl InvokeContext for MockInvokeContext {
         _deserialize_us: u64,
     ) {
     }
-    fn get_sysvar_data(&mut self, id: &Pubkey) -> Option<Rc<Vec<u8>>> {
+    fn get_sysvar_data(&self, id: &Pubkey) -> Option<Rc<Vec<u8>>> {
         self.sysvars
             .iter()
             .find_map(|(key, sysvar)| if id == key { sysvar.clone() } else { None })