[Valgrind-developers] valgrind: r7184 - trunk/coregrind

[<sv...@va...>]

Author: sewardj
Date: 2007-11-19 02:01:01 +0000 (Mon, 19 Nov 2007)
New Revision: 7184

Log:
Minor tidyings to the debugger-attach code, as part of a failed
attempt to fix debugger attach on ppc32-linux and ppc64-linux (see
#151908).  The fork/ptrace-based mechanism works fine for x86-linux
and amd64-linux but not on ppc.  I have no idea what is going on.

It seems like the forked child process (to which we will attach GDB)
does not stop when it does PTRACE_TRACE_ME and so things go downhill
very rapidly after that.

Modified:
   trunk/coregrind/m_debugger.c
   trunk/coregrind/m_errormgr.c


Modified: trunk/coregrind/m_debugger.c
===================================================================
--- trunk/coregrind/m_debugger.c	2007-11-19 00:58:18 UTC (rev 7183)
+++ trunk/coregrind/m_debugger.c	2007-11-19 02:01:01 UTC (rev 7184)
@@ -170,13 +170,20 @@
 void VG_(start_debugger) ( ThreadId tid )
 {
 #  define N_BUF 4096
-   Int pid;
+   Int pid, rc;
 
-   if ((pid = VG_(fork)()) == 0) {
-      VG_(ptrace)(VKI_PTRACE_TRACEME, 0, NULL, NULL);
-      VG_(kill)(VG_(getpid)(), VKI_SIGSTOP);
+   pid = VG_(fork)();
 
+   if (pid == 0) {
+      vki_sigset_t set;
+      /* child */
+      rc = VG_(ptrace)(VKI_PTRACE_TRACEME, 0, NULL, NULL);
+      vg_assert(rc == 0);
+      rc = VG_(kill)(VG_(getpid)(), VKI_SIGSTOP);
+      vg_assert(rc == 0);
+
    } else if (pid > 0) {
+      /* parent */
       Int status;
       Int res;
 

Modified: trunk/coregrind/m_errormgr.c
===================================================================
--- trunk/coregrind/m_errormgr.c	2007-11-19 00:58:18 UTC (rev 7183)
+++ trunk/coregrind/m_errormgr.c	2007-11-19 02:01:01 UTC (rev 7184)
@@ -455,7 +455,7 @@
    if (allow_db_attach &&
        VG_(is_action_requested)( "Attach to debugger", & VG_(clo_db_attach) ))
    {   
-      VG_(printf)("starting debugger\n");
+      if (0) VG_(printf)("starting debugger\n");
       VG_(start_debugger)( err->tid );
    }  
    /* Or maybe we want to generate the error's suppression? */