Committed: sim/cris: support open+fdopen syscall sequence.

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Committed: sim/cris: support open+fdopen syscall sequence.

Hans-Peter Nilsson
This supports a kind of open+fdopen sequence used in bzip2.
That sequence allegedly fixes a race condition appearing with
plain fopen, so perhaps it'll be seen in other programs that one
may want to run in a simulator.  Of course, I *could've*
introduced fcntl support in the callback machinery including
mapping forth and back and whatnot, but I don't think the added
complexity would do much good.

sim/:
        * cris/sim-main.h (struct _sim_cpu): New members last_syscall,
        last_open_fd, last_open_flags.
        * cris/traps.c: Don't include targ-vals.h.
        (TARGET_O_ACCMODE): Define.
        (cris_break_13_handler): Set new _sim_cpu members.
        <case TARGET_SYS_fcntl>: Support special case of F_GETFL.
        Rearrange code as switch.  Emit "unimplemented" abort for
        unimplemented fcntl calls.

Index: cris/sim-main.h
===================================================================
RCS file: /cvs/src/src/sim/cris/sim-main.h,v
retrieving revision 1.2
diff -p -u -r1.2 sim-main.h
--- cris/sim-main.h 24 Mar 2005 06:12:42 -0000 1.2
+++ cris/sim-main.h 17 Nov 2005 16:13:04 -0000
@@ -166,6 +166,17 @@ struct _sim_cpu {
      for sigmasks and sigpendings. */
   USI sighandler[64];
 
+  /* This is a hack to implement just the parts of fcntl F_GETFL that
+     are used in open+fdopen calls for the standard scenario: for such
+     a call we check that the last syscall was open, we check that the
+     passed fd is the same returned then, and so we return the same
+     flags passed to open.  This way, we avoid complicating the
+     generic sim callback machinery by introducing fcntl
+     mechanisms.  */
+  USI last_syscall;
+  USI last_open_fd;
+  USI last_open_flags;
+
   /* Function for initializing CPU thread context, which varies in size
      with each CPU model.  They should be in some constant parts or
      initialized in *_init_cpu, but we can't modify that for now.  */
Index: cris/traps.c
===================================================================
RCS file: /cvs/src/src/sim/cris/traps.c,v
retrieving revision 1.4
diff -p -u -r1.4 traps.c
--- cris/traps.c 17 Nov 2005 15:51:24 -0000 1.4
+++ cris/traps.c 17 Nov 2005 16:13:06 -0000
@@ -20,8 +20,9 @@ with this program; if not, write to the
 
 #include "sim-main.h"
 #include "sim-options.h"
-#include "targ-vals.h"
 #include "bfd.h"
+/* FIXME: get rid of targ-vals.h usage everywhere else.  */
+
 #ifdef HAVE_ERRNO_H
 #include <errno.h>
 #endif
@@ -663,6 +664,9 @@ static const CB_TARGET_DEFS_MAP errno_ma
    installation and removing synonyms and unnecessary items.  Don't
    forget the end-marker.  */
 
+/* This one we treat specially, as it's used in the fcntl syscall.  */
+#define TARGET_O_ACCMODE 3
+
 static const CB_TARGET_DEFS_MAP open_map[] = {
 #ifdef O_ACCMODE
   { O_ACCMODE, 0x3 },
@@ -1399,8 +1403,9 @@ cris_break_13_handler (SIM_CPU *current_
 
  case TARGET_SYS_fcntl64:
  case TARGET_SYS_fcntl:
-  if (arg2 == 1)
+  switch (arg2)
     {
+    case 1:
       /* F_GETFD.
  Glibc checks stdin, stdout and stderr fd:s for
  close-on-exec security sanity.  We just need to provide a
@@ -1408,12 +1413,35 @@ cris_break_13_handler (SIM_CPU *current_
  close-on-exec flag true, we could just do a real fcntl
  here.  */
       retval = 0;
-    }
-  else if (arg2 == 2)
-    {
+      break;
+
+    case 2:
       /* F_SETFD.  Just ignore attempts to set the close-on-exec
  flag.  */
       retval = 0;
+      break;
+
+    case 3:
+      /* F_GETFL.  Check for the special case for open+fdopen.  */
+      if (current_cpu->last_syscall == TARGET_SYS_open
+  && arg1 == current_cpu->last_open_fd)
+ {
+  retval = current_cpu->last_open_flags & TARGET_O_ACCMODE;
+  break;
+ }
+      /* FALLTHROUGH */
+      /* Abort for all other cases.  */
+    default:
+      sim_io_eprintf (sd, "Unimplemented %s syscall "
+      "(fd: 0x%lx: cmd: 0x%lx arg: 0x%lx)\n",
+      callnum == TARGET_SYS_fcntl
+      ? "fcntl" : "fcntl64",
+      (unsigned long) (USI) arg1,
+      (unsigned long) (USI) arg2,
+      (unsigned long) (USI) arg3);
+      sim_engine_halt (sd, current_cpu, NULL, pc, sim_stopped,
+       SIM_SIGILL);
+      break;
     }
   break;
 
@@ -2819,6 +2847,14 @@ cris_break_13_handler (SIM_CPU *current_
  }
     }
 
+  /* Minimal support for fcntl F_GETFL as used in open+fdopen.  */
+  if (callnum == TARGET_SYS_open)
+    {
+      current_cpu->last_open_fd = retval;
+      current_cpu->last_open_flags = arg2;
+    }
+  current_cpu->last_syscall = callnum;
+
   /* A system call is a rescheduling point.  For the time being, we don't
      reschedule anywhere else.  */
   if (current_cpu->m1threads != 0

brgds, H-P