From ce94282e1cf3f6a415ebb960e053f5f0ebdea3a1 Mon Sep 17 00:00:00 2001
From: edef <edef@unfathomable.blue>
Date: Fri, 29 Jul 2022 17:10:40 +0000
Subject: ripple/minitrace: interpret CString arguments to syscalls

Change-Id: Ib8ddefb7a969e5cfd7e891233d083670a0c72596
---
 ripple/minitrace/src/main.rs | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/ripple/minitrace/src/main.rs b/ripple/minitrace/src/main.rs
index eaabad0..09b694c 100644
--- a/ripple/minitrace/src/main.rs
+++ b/ripple/minitrace/src/main.rs
@@ -108,11 +108,11 @@ macro_rules! define_syscalls {
 		}
 
 		impl $SyscallEntry {
-			fn from_regs(regs: libc::user_regs_struct) -> Result<$SyscallEntry> {
+			fn from_regs(process: &Process, regs: libc::user_regs_struct) -> Result<$SyscallEntry> {
 				Ok(match (regs.orig_rax, [regs.rdi, regs.rsi, regs.rdx, regs.r10, regs.r8, regs.r9]) {
 					$(
 						($nr, [$($arg),*, ..]) => $SyscallEntry::$syscall {
-							$($arg: match SyscallArg::try_from_reg($arg) {
+							$($arg: match ProcessSyscallArg::try_from_process_reg(process, $arg) {
 								Some(x) => x,
 								None => bail!("couldn't parse {}(2) {}: 0x{:08x}", stringify!($syscall), stringify!($arg), $arg)
 							}),*
@@ -178,6 +178,22 @@ macro_rules! syscall_bitflags {
 	};
 }
 
+trait ProcessSyscallArg: Sized {
+	fn try_from_process_reg(process: &Process, reg: u64) -> Option<Self>;
+}
+
+impl ProcessSyscallArg for CString {
+	fn try_from_process_reg(process: &Process, reg: u64) -> Option<Self> {
+		process.read_mem_cstr(reg).ok()
+	}
+}
+
+impl<T: SyscallArg> ProcessSyscallArg for T {
+	fn try_from_process_reg(_process: &Process, reg: u64) -> Option<Self> {
+		SyscallArg::try_from_reg(reg)
+	}
+}
+
 trait SyscallArg: Sized {
 	fn try_from_reg(reg: u64) -> Option<Self>;
 }
@@ -328,7 +344,7 @@ fn main() -> Result<()> {
 				assert_eq!(tid, event_tid);
 
 				let regs = ptrace::getregs(event_tid.as_pid())?;
-				let entry = match SyscallEntry::from_regs(regs) {
+				let entry = match SyscallEntry::from_regs(&process, regs) {
 					Ok(entry) => entry,
 					Err(err) => {
 						ptrace::kill(event_tid.as_pid())?;
-- 
cgit 1.4.1