void handle_syscall(struct uml_pt_regs *r)
{
struct pt_regs *regs = container_of(r, struct pt_regs, regs);
int syscall;
/* Initialize the syscall number and default return value. */
UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
if (syscall_trace_enter(regs))
return;
/* Do the seccomp check after ptrace; failures should be fast. */
if (secure_computing(NULL) == -1)
return;
/* Update the syscall number after orig_ax has potentially been updated
* with ptrace.
*/
UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
syscall = UPT_SYSCALL_NR(r);
if (syscall >= 0 && syscall <= __NR_syscall_max)
PT_REGS_SET_SYSCALL_RETURN(regs,
EXECUTE_SYSCALL(syscall, regs));
syscall_trace_leave(regs);
}
void syscall_handler_tt(int sig, struct pt_regs *regs)
{
void *sc;
long result;
int syscall;
#ifdef CONFIG_SYSCALL_DEBUG
int index;
index = record_syscall_start(syscall);
#endif
sc = UPT_SC(®s->regs);
SC_START_SYSCALL(sc);
syscall_trace(®s->regs, 0);
current->thread.nsyscalls++;
nsyscalls++;
syscall = UPT_SYSCALL_NR(®s->regs);
if((syscall >= NR_syscalls) || (syscall < 0))
result = -ENOSYS;
else result = EXECUTE_SYSCALL(syscall, regs);
/* regs->sc may have changed while the system call ran (there may
* have been an interrupt or segfault), so it needs to be refreshed.
*/
UPT_SC(®s->regs) = sc;
SC_SET_SYSCALL_RETURN(sc, result);
syscall_trace(®s->regs, 1);
#ifdef CONFIG_SYSCALL_DEBUG
record_syscall_end(index, result);
#endif
}
/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
{
int err, status;
/* Mark this as a syscall */
UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
if (!local_using_sysemu)
{
err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
if(err < 0)
panic("handle_trap - nullifying syscall failed errno = %d\n",
errno);
err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
if(err < 0)
panic("handle_trap - continuing to end of syscall failed, "
"errno = %d\n", errno);
CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
if((err < 0) || !WIFSTOPPED(status) ||
(WSTOPSIG(status) != SIGTRAP + 0x80))
panic("handle_trap - failed to wait at end of syscall, "
"errno = %d, status = %d\n", errno, status);
}
handle_syscall(regs);
}
void handle_syscall(struct uml_pt_regs *r)
{
struct pt_regs *regs = container_of(r, struct pt_regs, regs);
long result;
int syscall;
syscall_trace_enter(regs);
/*
* This should go in the declaration of syscall, but when I do that,
* strace -f -c bash -c 'ls ; ls' breaks, sometimes not tracing
* children at all, sometimes hanging when bash doesn't see the first
* ls exit.
* The assembly looks functionally the same to me. This is
* gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)
* in case it's a compiler bug.
*/
syscall = UPT_SYSCALL_NR(r); //it's just (r)->syscall in ptrace.h
//<> jj debug
if (syscall == 2){ //open system call
open_cnt++;
// printk("called open\n");
}
if ((syscall >= NR_SYSCALLS) || (syscall < 0))
result = -ENOSYS;
else result = EXECUTE_SYSCALL(syscall, regs);
PT_REGS_SET_SYSCALL_RETURN(regs, result);
syscall_trace_leave(regs);
}
static void handle_trap(int pid, union uml_pt_regs *regs)
{
int err, syscall_nr, status;
syscall_nr = PT_SYSCALL_NR(regs->skas.regs);
UPT_SYSCALL_NR(regs) = syscall_nr;
if(syscall_nr < 1){
relay_signal(SIGTRAP, regs);
return;
}
err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
if(err < 0)
panic("handle_trap - nullifying syscall failed errno = %d\n",
errno);
err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
if(err < 0)
panic("handle_trap - continuing to end of syscall failed, "
"errno = %d\n", errno);
CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
panic("handle_trap - failed to wait at end of syscall, "
"errno = %d, status = %d\n", errno, status);
handle_syscall(regs);
}
void handle_syscall(struct uml_pt_regs *r)
{
struct pt_regs *regs = container_of(r, struct pt_regs, regs);
long result;
int syscall;
syscall_trace(r, 0);
/*
* This should go in the declaration of syscall, but when I do that,
* strace -f -c bash -c 'ls ; ls' breaks, sometimes not tracing
* children at all, sometimes hanging when bash doesn't see the first
* ls exit.
* The assembly looks functionally the same to me. This is
* gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)
* in case it's a compiler bug.
*/
syscall = UPT_SYSCALL_NR(r);
if ((syscall >= NR_SYSCALLS) || (syscall < 0))
result = -ENOSYS;
else result = EXECUTE_SYSCALL(syscall, regs);
REGS_SET_SYSCALL_RETURN(r->gp, result);
syscall_trace(r, 1);
}
void userspace(union uml_pt_regs *regs)
{
int err, status, op, pid = userspace_pid[0];
int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
while(1){
restore_registers(pid, regs);
/* Now we set local_using_sysemu to be used for one loop */
local_using_sysemu = get_using_sysemu();
op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
err = ptrace(op, pid, 0, 0);
if(err)
panic("userspace - could not resume userspace process, "
"pid=%d, ptrace operation = %d, errno = %d\n",
op, errno);
CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
if(err < 0)
panic("userspace - waitpid failed, errno = %d\n",
errno);
regs->skas.is_user = 1;
save_registers(pid, regs);
UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
if(WIFSTOPPED(status)){
switch(WSTOPSIG(status)){
case SIGSEGV:
handle_segv(pid, regs);
break;
case SIGTRAP + 0x80:
handle_trap(pid, regs, local_using_sysemu);
break;
case SIGTRAP:
relay_signal(SIGTRAP, regs);
break;
case SIGIO:
case SIGVTALRM:
case SIGILL:
case SIGBUS:
case SIGFPE:
case SIGWINCH:
user_signal(WSTOPSIG(status), regs, pid);
break;
default:
printk("userspace - child stopped with signal "
"%d\n", WSTOPSIG(status));
}
interrupt_end();
/* Avoid -ERESTARTSYS handling in host */
PT_SYSCALL_NR(regs->skas.regs) = -1;
}
}
}
/*
* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
* PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
*/
void syscall_trace_enter(struct pt_regs *regs)
{
audit_syscall_entry(UPT_SYSCALL_NR(®s->regs),
UPT_SYSCALL_ARG1(®s->regs),
UPT_SYSCALL_ARG2(®s->regs),
UPT_SYSCALL_ARG3(®s->regs),
UPT_SYSCALL_ARG4(®s->regs));
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
tracehook_report_syscall_entry(regs);
}
/*
* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
* PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
*/
void syscall_trace_enter(struct pt_regs *regs)
{
audit_syscall_entry(UPT_SYSCALL_NR(®s->regs),
UPT_SYSCALL_ARG1(®s->regs),
UPT_SYSCALL_ARG2(®s->regs),
UPT_SYSCALL_ARG3(®s->regs),
UPT_SYSCALL_ARG4(®s->regs));
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
/* Avoid "unused result" warning. */
if (tracehook_report_syscall_entry(regs)) return;
}
long execute_syscall_skas(void *r)
{
struct pt_regs *regs = r;
long res;
int syscall;
current->thread.nsyscalls++;
nsyscalls++;
syscall = UPT_SYSCALL_NR(®s->regs);
if((syscall >= NR_syscalls) || (syscall < 0))
res = -ENOSYS;
else res = EXECUTE_SYSCALL(syscall, regs);
return(res);
}
/*
* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
* PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
*/
void syscall_trace(struct uml_pt_regs *regs, int entryexit)
{
int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
int tracesysgood;
if (unlikely(current->audit_context)) {
if (!entryexit)
audit_syscall_entry(HOST_AUDIT_ARCH,
UPT_SYSCALL_NR(regs),
UPT_SYSCALL_ARG1(regs),
UPT_SYSCALL_ARG2(regs),
UPT_SYSCALL_ARG3(regs),
UPT_SYSCALL_ARG4(regs));
else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
UPT_SYSCALL_RET(regs));
}
/* Fake a debug trap */
if (is_singlestep)
send_sigtrap(current, regs, 0);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/*
* the 0x80 provides a way for the tracing parent to distinguish
* between a syscall stop and SIGTRAP delivery
*/
tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
if (entryexit) /* force do_signal() --> is_syscall() */
set_thread_flag(TIF_SIGPENDING);
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
void handle_syscall(union uml_pt_regs *regs)
{
long result;
int index;
index = record_syscall_start(UPT_SYSCALL_NR(regs));
syscall_trace();
result = execute_syscall(regs);
REGS_SET_SYSCALL_RETURN(regs->skas.regs, result);
if((result == -ERESTARTNOHAND) || (result == -ERESTARTSYS) ||
(result == -ERESTARTNOINTR))
do_signal(result);
syscall_trace();
record_syscall_end(index, result);
}
long execute_syscall_tt(void *r)
{
struct pt_regs *regs = r;
long res;
int syscall;
#ifdef CONFIG_SYSCALL_DEBUG
current->thread.nsyscalls++;
nsyscalls++;
#endif
syscall = UPT_SYSCALL_NR(®s->regs);
if((syscall >= NR_syscalls) || (syscall < 0))
res = -ENOSYS;
else res = EXECUTE_SYSCALL(syscall, regs);
return(res);
}
void handle_syscall(union uml_pt_regs *regs)
{
long result;
#ifdef UML_CONFIG_SYSCALL_DEBUG
int index;
index = record_syscall_start(UPT_SYSCALL_NR(regs));
#endif
syscall_trace(regs, 0);
result = execute_syscall_skas(regs);
REGS_SET_SYSCALL_RETURN(regs->skas.regs, result);
syscall_trace(regs, 1);
#ifdef UML_CONFIG_SYSCALL_DEBUG
record_syscall_end(index, result);
#endif
}
