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Fix ptrace bug when reattaching to a detached process

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This commit is contained in:
David van Moolenbroek 2009-11-09 08:12:25 +00:00
parent ebbce7507b
commit a07f8d7646
3 changed files with 92 additions and 1 deletions
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4
kernel/system/do_trace.c
View file

@ -163,6 +163,10 @@ register message *m_ptr;
m_ptr->CTL_DATA = 0;
break;
case T_DETACH: /* detach tracer */
rp->p_misc_flags &= ~MF_SC_ACTIVE;
/* fall through */
case T_RESUME: /* resume execution */
RTS_LOCK_UNSET(rp, P_STOP);
m_ptr->CTL_DATA = 0;

1
servers/pm/trace.c
View file

@ -175,7 +175,6 @@ PUBLIC int do_trace()
/* Resume the child as if nothing ever happened. */
child->mp_flags &= ~STOPPED;
child->mp_trace_flags = 0;
req = T_RESUME;
check_pending(child);

88
test/test42.c
View file

@ -7,6 +7,7 @@
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/select.h>
#include <sys/ptrace.h>
#define ITERATIONS 3
@ -56,6 +57,8 @@ _PROTOTYPE(void test_syscall_child, (void));
_PROTOTYPE(void test_syscall, (void));
_PROTOTYPE(void test_tracefork_child, (void));
_PROTOTYPE(void test_tracefork, (void));
_PROTOTYPE(void test_reattach_child, (void));
_PROTOTYPE(void test_reattach, (void));
_PROTOTYPE(void altexec, (int setflag, int *traps, int *stop));
_PROTOTYPE(void test_altexec, (void));
_PROTOTYPE(void test_noaltexec, (void));
@ -120,6 +123,7 @@ int a;
if (m & 0020000) test_tracefork();
if (m & 0040000) test_altexec();
if (m & 0100000) test_noaltexec();
if (m & 0200000) test_reattach();
}
pid_t traced_fork(c)
@ -1322,6 +1326,90 @@ void test_noaltexec()
if (stop >= 0) e(14);
}
void test_reattach_child()
{
struct timeval tv;
if (READ() != 0) e(100);
tv.tv_sec = 2;
tv.tv_usec = 0;
if (select(0, NULL, NULL, NULL, &tv) != 0) e(101);
exit(42);
}
void test_reattach()
{
pid_t pid;
int r, status, count;
subtest = 17;
pid = traced_fork(test_reattach_child);
if (kill(pid, SIGSTOP) != 0) e(1);
if (waitpid(pid, &status, 0) != pid) e(2);
if (!_WIFSTOPPED(status)) e(3);
if (WSTOPSIG(status) != SIGSTOP) e(4);
WRITE(0);
signal(SIGALRM, dummy_handler);
alarm(1);
/* Start tracing system calls. We don't know how many there will be until
* we reach the child's select(), so we have to interrupt ourselves.
*/
if (ptrace(T_SYSCALL, pid, 0, 0) != 0) e(5);
for (count = 0; (r = waitpid(pid, &status, 0)) == pid; count++) {
if (!_WIFSTOPPED(status)) e(6);
if (WSTOPSIG(status) != SIGTRAP) e(7);
if (ptrace(T_SYSCALL, pid, 0, 0) != 0) e(8);
}
if (r != -1 || errno != EINTR) e(9);
/* We always start with syscall enter event; the last event we should have
* seen before the alarm was entering the select() call.
*/
if (!(count % 2)) e(10);
/* Detach, and immediately attach again. */
detach_running(pid);
if (ptrace(T_ATTACH, pid, 0, 0) != 0) e(11);
if (waitpid(pid, &status, 0) != pid) e(12);
if (!_WIFSTOPPED(status)) e(13);
if (WSTOPSIG(status) != SIGSTOP) e(14);
if (ptrace(T_SYSCALL, pid, 0, 0) != 0) e(15);
if (waitpid(pid, &status, 0) != pid) e(16);
for (count = 0; _WIFSTOPPED(status); count++) {
if (WSTOPSIG(status) != SIGTRAP) e(17);
if (ptrace(T_SYSCALL, pid, 0, 0) != 0) e(18);
if (waitpid(pid, &status, 0) != pid) e(19);
}
if (!_WIFEXITED(status)) e(20);
if ((r = WEXITSTATUS(status)) != 42) e(r);
/* We must not have seen the select()'s syscall leave event, and the last
* event will be the syscall enter for the exec().
*/
if (!(count % 2)) e(21);
traced_wait();
}
void e(n)
int n;
{