The branch main has been updated by trasz:
URL:
https://cgit.FreeBSD.org/src/commit/?id=6e66030c4c05331f9b0adf87c31f2f233dd3ae1f
commit 6e66030c4c05331f9b0adf87c31f2f233dd3ae1f
Author: Edward Tomasz Napierala <tr...@freebsd.org>
AuthorDate: 2021-10-23 18:13:14 +0000
Commit: Edward Tomasz Napierala <tr...@freebsd.org>
CommitDate: 2021-10-23 18:46:26 +0000
linux: implement PTRACE_EVENT_EXEC
This fixes strace(1) from Ubuntu Focal.
Reviewed By: jhb
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D32367
---
sys/amd64/linux/linux_ptrace.c | 9 +++++++--
sys/kern/subr_syscall.c | 12 ++++++++++++
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/sys/amd64/linux/linux_ptrace.c b/sys/amd64/linux/linux_ptrace.c
index 37f136856ef0..d7dffc92dd11 100644
--- a/sys/amd64/linux/linux_ptrace.c
+++ b/sys/amd64/linux/linux_ptrace.c
@@ -71,6 +71,7 @@ __FBSDID("$FreeBSD$");
#define LINUX_PTRACE_SEIZE 0x4206
#define LINUX_PTRACE_GET_SYSCALL_INFO 0x420e
+#define LINUX_PTRACE_EVENT_EXEC 4
#define LINUX_PTRACE_EVENT_EXIT 6
#define LINUX_PTRACE_O_TRACESYSGOOD 1
@@ -151,8 +152,12 @@ linux_ptrace_status(struct thread *td, pid_t pid, int
status)
lwpinfo.pl_flags & PL_FLAG_SCE)
status |= (LINUX_SIGTRAP | 0x80) << 8;
if ((pem->ptrace_flags & LINUX_PTRACE_O_TRACESYSGOOD) &&
- lwpinfo.pl_flags & PL_FLAG_SCX)
- status |= (LINUX_SIGTRAP | 0x80) << 8;
+ lwpinfo.pl_flags & PL_FLAG_SCX) {
+ if (lwpinfo.pl_flags & PL_FLAG_EXEC)
+ status |= (LINUX_SIGTRAP | LINUX_PTRACE_EVENT_EXEC <<
8) << 8;
+ else
+ status |= (LINUX_SIGTRAP | 0x80) << 8;
+ }
if ((pem->ptrace_flags & LINUX_PTRACE_O_TRACEEXIT) &&
lwpinfo.pl_flags & PL_FLAG_EXITED)
status |= (LINUX_SIGTRAP | LINUX_PTRACE_EVENT_EXIT << 8) << 8;
diff --git a/sys/kern/subr_syscall.c b/sys/kern/subr_syscall.c
index ada2053bc87c..fab67a68b0a3 100644
--- a/sys/kern/subr_syscall.c
+++ b/sys/kern/subr_syscall.c
@@ -254,6 +254,18 @@ syscallret(struct thread *td)
if (__predict_false(traced ||
(td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0)) {
PROC_LOCK(p);
+ /*
+ * Linux debuggers expect an additional stop for exec,
+ * between the usual syscall entry and exit. Raise
+ * the exec event now and then clear TDB_EXEC so that
+ * the next stop is reported as a syscall exit by
+ * linux_ptrace_status().
+ */
+ if ((td->td_dbgflags & TDB_EXEC) != 0 &&
+ SV_PROC_ABI(td->td_proc) == SV_ABI_LINUX) {
+ ptracestop(td, SIGTRAP, NULL);
+ td->td_dbgflags &= ~TDB_EXEC;
+ }
/*
* If tracing the execed process, trap to the debugger
* so that breakpoints can be set before the program
