diff options
Diffstat (limited to 'src/libmach/linux.c')
| -rw-r--r-- | src/libmach/linux.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/src/libmach/linux.c b/src/libmach/linux.c index 30b4da240..6ce18957f 100644 --- a/src/libmach/linux.c +++ b/src/libmach/linux.c @@ -238,8 +238,7 @@ fixup: PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE | PTRACE_O_TRACEEXEC | - PTRACE_O_TRACEVFORKDONE | - PTRACE_O_TRACEEXIT; + PTRACE_O_TRACEVFORKDONE; if(ptrace(PTRACE_SETOPTIONS, tid, 0, (void*)flags) < 0) { fprint(2, "ptrace PTRACE_SETOPTIONS %d: %r\n", tid); return nil; @@ -358,6 +357,12 @@ wait1(int nohang) break; case PTRACE_EVENT_EXIT: + // We won't see this unless we set PTRACE_O_TRACEEXIT. + // The debuggers assume that a read or write on a Map + // will fail for a thread that has exited. This event + // breaks that assumption. It's not a big deal: we + // only lose the ability to see the register state at + // the time of exit. if(trace) fprint(2, "tid %d: exiting %#x\n", tid, status); t->state = Exiting; @@ -755,13 +760,19 @@ static int ptracerw(int type, int xtype, int isr, int pid, uvlong addr, void *v, uint n) { int i; - uintptr u; + uintptr u, a; uchar buf[sizeof(uintptr)]; for(i=0; i<n; i+=sizeof(uintptr)){ + // Tread carefully here. On recent versions of glibc, + // ptrace is a variadic function which means the third + // argument will be pushed onto the stack as a uvlong. + // This is fine on amd64 but will not work for 386. + // We must convert addr to a uintptr. + a = addr+i; if(isr){ errno = 0; - u = ptrace(type, pid, addr+i, 0); + u = ptrace(type, pid, a, 0); if(errno) goto ptraceerr; if(n-i >= sizeof(uintptr)) @@ -775,14 +786,14 @@ ptracerw(int type, int xtype, int isr, int pid, uvlong addr, void *v, uint n) u = *(uintptr*)((char*)v+i); else{ errno = 0; - u = ptrace(xtype, pid, addr+i, 0); + u = ptrace(xtype, pid, a, 0); if(errno) return -1; memmove(buf, &u, sizeof u); memmove(buf, (char*)v+i, n-i); memmove(&u, buf, sizeof u); } - if(ptrace(type, pid, addr+i, u) < 0) + if(ptrace(type, pid, a, u) < 0) goto ptraceerr; } } |