From 55e600d7fb35ccff5c2a024b2f3392ba31cf48ab Mon Sep 17 00:00:00 2001 From: jhb Date: Fri, 19 Aug 2016 20:17:57 +0000 Subject: MFC 303001: Add PTRACE_VFORK to trace vfork events. First, PL_FLAG_FORKED events now also set a PL_FLAG_VFORKED flag when the new child was created via vfork() rather than fork(). Second, a new PL_FLAG_VFORK_DONE event can now be enabled via the PTRACE_VFORK event mask. This new stop is reported after the vfork parent resumes due to the child calling exit or exec. Debuggers can use this stop to reinsert breakpoints in the vfork parent process before it resumes. --- tests/sys/kern/ptrace_test.c | 126 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) (limited to 'tests') diff --git a/tests/sys/kern/ptrace_test.c b/tests/sys/kern/ptrace_test.c index be978ed..dede0f8 100644 --- a/tests/sys/kern/ptrace_test.c +++ b/tests/sys/kern/ptrace_test.c @@ -1549,6 +1549,130 @@ ATF_TC_BODY(ptrace__event_mask, tc) ATF_REQUIRE(errno == ECHILD); } +/* + * Verify that the expected ptrace events are reported for PTRACE_VFORK. + */ +ATF_TC_WITHOUT_HEAD(ptrace__ptrace_vfork); +ATF_TC_BODY(ptrace__ptrace_vfork, tc) +{ + struct ptrace_lwpinfo pl; + pid_t fpid, wpid; + int events, status; + + ATF_REQUIRE((fpid = fork()) != -1); + if (fpid == 0) { + trace_me(); + follow_fork_parent(true); + } + + /* The first wait() should report the stop from SIGSTOP. */ + wpid = waitpid(fpid, &status, 0); + ATF_REQUIRE(wpid == fpid); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + ATF_REQUIRE(ptrace(PT_GET_EVENT_MASK, fpid, (caddr_t)&events, + sizeof(events)) == 0); + events |= PTRACE_VFORK; + ATF_REQUIRE(ptrace(PT_SET_EVENT_MASK, fpid, (caddr_t)&events, + sizeof(events)) == 0); + + /* Continue the child ignoring the SIGSTOP. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, fpid, (caddr_t)1, 0) != -1); + + /* The next event should report the end of the vfork. */ + wpid = wait(&status); + ATF_REQUIRE(wpid == fpid); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGTRAP); + ATF_REQUIRE(ptrace(PT_LWPINFO, wpid, (caddr_t)&pl, sizeof(pl)) != -1); + ATF_REQUIRE((pl.pl_flags & PL_FLAG_VFORK_DONE) != 0); + + ATF_REQUIRE(ptrace(PT_CONTINUE, fpid, (caddr_t)1, 0) != -1); + + wpid = wait(&status); + ATF_REQUIRE(wpid == fpid); + ATF_REQUIRE(WIFEXITED(status)); + ATF_REQUIRE(WEXITSTATUS(status) == 1); + + wpid = wait(&status); + ATF_REQUIRE(wpid == -1); + ATF_REQUIRE(errno == ECHILD); +} + +ATF_TC_WITHOUT_HEAD(ptrace__ptrace_vfork_follow); +ATF_TC_BODY(ptrace__ptrace_vfork_follow, tc) +{ + struct ptrace_lwpinfo pl[2]; + pid_t children[2], fpid, wpid; + int events, status; + + ATF_REQUIRE((fpid = fork()) != -1); + if (fpid == 0) { + trace_me(); + follow_fork_parent(true); + } + + /* Parent process. */ + children[0] = fpid; + + /* The first wait() should report the stop from SIGSTOP. */ + wpid = waitpid(children[0], &status, 0); + ATF_REQUIRE(wpid == children[0]); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + ATF_REQUIRE(ptrace(PT_GET_EVENT_MASK, children[0], (caddr_t)&events, + sizeof(events)) == 0); + events |= PTRACE_FORK | PTRACE_VFORK; + ATF_REQUIRE(ptrace(PT_SET_EVENT_MASK, children[0], (caddr_t)&events, + sizeof(events)) == 0); + + /* Continue the child ignoring the SIGSTOP. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, children[0], (caddr_t)1, 0) != -1); + + /* Wait for both halves of the fork event to get reported. */ + children[1] = handle_fork_events(children[0], pl); + ATF_REQUIRE(children[1] > 0); + + ATF_REQUIRE((pl[0].pl_flags & PL_FLAG_VFORKED) != 0); + + ATF_REQUIRE(ptrace(PT_CONTINUE, children[0], (caddr_t)1, 0) != -1); + ATF_REQUIRE(ptrace(PT_CONTINUE, children[1], (caddr_t)1, 0) != -1); + + /* + * The child can't exit until the grandchild reports status, so the + * grandchild should report its exit first to the debugger. + */ + wpid = waitpid(children[1], &status, 0); + ATF_REQUIRE(wpid == children[1]); + ATF_REQUIRE(WIFEXITED(status)); + ATF_REQUIRE(WEXITSTATUS(status) == 2); + + /* + * The child should report it's vfork() completion before it + * exits. + */ + wpid = wait(&status); + ATF_REQUIRE(wpid == children[0]); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGTRAP); + ATF_REQUIRE(ptrace(PT_LWPINFO, wpid, (caddr_t)&pl[0], sizeof(pl[0])) != + -1); + ATF_REQUIRE((pl[0].pl_flags & PL_FLAG_VFORK_DONE) != 0); + + ATF_REQUIRE(ptrace(PT_CONTINUE, children[0], (caddr_t)1, 0) != -1); + + wpid = wait(&status); + ATF_REQUIRE(wpid == children[0]); + ATF_REQUIRE(WIFEXITED(status)); + ATF_REQUIRE(WEXITSTATUS(status) == 1); + + wpid = wait(&status); + ATF_REQUIRE(wpid == -1); + ATF_REQUIRE(errno == ECHILD); +} + ATF_TP_ADD_TCS(tp) { @@ -1574,6 +1698,8 @@ ATF_TP_ADD_TCS(tp) ATF_TP_ADD_TC(tp, ptrace__ptrace_exec_disable); ATF_TP_ADD_TC(tp, ptrace__ptrace_exec_enable); ATF_TP_ADD_TC(tp, ptrace__event_mask); + ATF_TP_ADD_TC(tp, ptrace__ptrace_vfork); + ATF_TP_ADD_TC(tp, ptrace__ptrace_vfork_follow); return (atf_no_error()); } -- cgit v1.1