Unify per-architecture post-execve SIGTRAP check.
Move post-execve SIGTRAP check from get_scno_on_sysenter
(multitude of places on many architectures) to a single location
in trace_syscall_entering. This loosens the logic for some arches,
since many of them had additional checks such as scno == 0.
However, on non-ancient Linux kernels we should never have post-execve
SIGTRAP in the first place, by virtue of using PTRACE_O_TRACEEXEC.
* syscall.c (get_scno_on_sysenter): Remove tcp->flags & TCB_WAITEXECVE checks.
(trace_syscall_entering): Do tcp->flags & TCB_WAITEXECVE check here.
(get_scno_on_sysexit): Tweak comment.
(syscall_fixup): Likewise.
(trace_syscall_exiting): Likewise.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/syscall.c b/syscall.c
index fc502bf..8ffa4a6 100644
--- a/syscall.c
+++ b/syscall.c
@@ -754,12 +754,6 @@
#ifdef LINUX
# if defined(S390) || defined(S390X)
- if (tcp->flags & TCB_WAITEXECVE) {
- /* This is the post-execve SIGTRAP. */
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
-
if (upeek(tcp, PT_GPR2, &syscall_mode) < 0)
return -1;
@@ -843,11 +837,6 @@
# elif defined (POWERPC)
if (upeek(tcp, sizeof(unsigned long)*PT_R0, &scno) < 0)
return -1;
- /* Check if this is the post-execve SIGTRAP. */
- if (scno == 0 && (tcp->flags & TCB_WAITEXECVE)) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# ifdef POWERPC64
/* TODO: speed up strace by not doing this at every syscall.
* We only need to do it after execve.
@@ -872,19 +861,10 @@
}
# endif
# elif defined(AVR32)
- /*
- * Read complete register set in one go.
- */
+ /* Read complete register set in one go. */
if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, ®s) < 0)
return -1;
-
scno = regs.r8;
-
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# elif defined(BFIN)
if (upeek(tcp, PT_ORIG_P0, &scno))
return -1;
@@ -969,15 +949,8 @@
if (upeek(tcp, PT_R15, &scno) < 0)
return -1;
}
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# elif defined (ARM)
- /*
- * Read complete register set in one go.
- */
+ /* Read complete register set in one go. */
if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (void *)®s) == -1)
return -1;
@@ -985,12 +958,6 @@
* We only need to grab the syscall number on syscall entry.
*/
if (regs.ARM_ip == 0) {
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
-
/*
* Note: we only deal with only 32-bit CPUs here.
*/
@@ -1008,14 +975,6 @@
if (errno)
return -1;
- /* FIXME: bogus check? it is already done before,
- * so we never can see it here?
- */
- if (scno == 0 && (tcp->flags & TCB_WAITEXECVE)) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
-
/* Handle the EABI syscall convention. We do not
bother converting structures between the two
ABIs, but basic functionality should work even
@@ -1061,13 +1020,6 @@
r2 = regs[REG_V0];
scno = r2;
-
- /* Check if this is the post-execve SIGTRAP. */
- if (scno == 0 && tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
-
if (scno < 0 || scno > nsyscalls) {
if (a3 == 0 || a3 == -1) {
if (debug)
@@ -1081,12 +1033,6 @@
if (upeek(tcp, REG_V0, &scno) < 0)
return -1;
- /* Check if this is the post-execve SIGTRAP. */
- if (scno == 0 && tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
-
if (scno < 0 || scno > nsyscalls) {
if (a3 == 0 || a3 == -1) {
if (debug)
@@ -1097,16 +1043,9 @@
# elif defined (ALPHA)
if (upeek(tcp, REG_A3, &a3) < 0)
return -1;
-
if (upeek(tcp, REG_R0, &scno) < 0)
return -1;
- /* Check if this is the post-execve SIGTRAP. */
- if (scno == 0 && tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
-
/*
* Do some sanity checks to figure out if it's
* really a syscall entry
@@ -1162,11 +1101,6 @@
set_personality(1);
break;
default:
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# if defined (SPARC64)
fprintf(stderr, "syscall: unknown syscall trap %08lx %016lx\n", trap, regs.tpc);
# else
@@ -1187,11 +1121,6 @@
# elif defined(HPPA)
if (upeek(tcp, PT_GR20, &scno) < 0)
return -1;
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# elif defined(SH)
/*
* In the new syscall ABI, the system call number is in R3.
@@ -1212,34 +1141,16 @@
correct_scno);
scno = correct_scno;
}
-
- /* Check if this is the post-execve SIGTRAP. */
- if (scno == 0 && tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# elif defined(SH64)
if (upeek(tcp, REG_SYSCALL, &scno) < 0)
return -1;
scno &= 0xFFFF;
-
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# elif defined(CRISV10) || defined(CRISV32)
if (upeek(tcp, 4*PT_R9, &scno) < 0)
return -1;
# elif defined(TILE)
if (upeek(tcp, PTREGS_OFFSET_REG(10), &scno) < 0)
return -1;
-
- /* Check if this is the post-execve SIGTRAP. */
- if (tcp->flags & TCB_WAITEXECVE) {
- tcp->flags &= ~TCB_WAITEXECVE;
- return 0;
- }
# elif defined(MICROBLAZE)
if (upeek(tcp, 0, &scno) < 0)
return -1;
@@ -1300,9 +1211,7 @@
# if defined(S390) || defined(S390X)
# elif defined (POWERPC)
# elif defined(AVR32)
- /*
- * Read complete register set in one go.
- */
+ /* Read complete register set in one go. */
if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, ®s) < 0)
return -1;
# elif defined(BFIN)
@@ -1321,9 +1230,7 @@
if (upeek(tcp, PT_R10, &r10) < 0)
return -1;
# elif defined (ARM)
- /*
- * Read complete register set in one go.
- */
+ /* Read complete register set in one go. */
if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (void *)®s) == -1)
return -1;
# elif defined (M68K)
@@ -1511,6 +1418,7 @@
== (TCB_INSYSCALL|TCB_WAITEXECVE))
&& (gpr2 == -ENOSYS || gpr2 == tcp->scno)) {
/*
+ * Return from execve.
* Fake a return value of zero. We leave the TCB_WAITEXECVE
* flag set for the post-execve SIGTRAP to see and reset.
*/
@@ -2308,6 +2216,14 @@
{
int res, scno_good;
+#if defined TCB_WAITEXECVE
+ if (tcp->flags & TCB_WAITEXECVE) {
+ /* This is the post-execve SIGTRAP. */
+ tcp->flags &= ~TCB_WAITEXECVE;
+ return 0;
+ }
+#endif
+
scno_good = res = get_scno_on_sysenter(tcp);
if (res == 0)
return res;
@@ -2477,9 +2393,6 @@
if (dtime || cflag)
gettimeofday(&tv, NULL);
- /* BTW, why we don't just memorize syscall no. on entry
- * in tcp->something?
- */
scno_good = res = get_scno_on_sysexit(tcp);
if (res == 0)
return res;