Date: Sat, 23 Oct 2021 18:46:34 GMT From: Edward Tomasz Napierala <trasz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 6e66030c4c05 - main - linux: implement PTRACE_EVENT_EXEC Message-ID: <202110231846.19NIkYg9047888@gitrepo.freebsd.org>
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The branch main has been updated by trasz: URL: https://cgit.FreeBSD.org/src/commit/?id=6e66030c4c05331f9b0adf87c31f2f233dd3ae1f commit 6e66030c4c05331f9b0adf87c31f2f233dd3ae1f Author: Edward Tomasz Napierala <trasz@FreeBSD.org> AuthorDate: 2021-10-23 18:13:14 +0000 Commit: Edward Tomasz Napierala <trasz@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
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