[patch, sim, mips] Implement unlink, lseek, and stat for MIPS

["Steve Ellcey " <sellcey@mips.com>]

A while back I submitted a GCC patch that allowed me to build the Fortran
compiler on a newlib based cross compiler.  While using the GNU simulator
to test that, I found that a number of tests failed due to unimplemented
system calls on the MIPS GNU simulator.  This patch implements unlink,
lseek, and stat in the GNU simulator for MIPS.  There is a second small
patch that I sent to newlib that generates the necessary functions for
the simulator to see and intercept these functions like it does others
that are already implemented such as open and close.

OK to checkin?

Steve Ellcey
sellcey@mips.com


Steve Ellcey  <sellcey@mips.com>

	* interp.c (sim_monitor): Add switch entries for unlink (13),
	lseek (14), and stat (15).


diff --git a/sim/mips/interp.c b/sim/mips/interp.c
index 032570a..766a113 100644
--- a/sim/mips/interp.c
+++ b/sim/mips/interp.c
@@ -47,6 +47,7 @@ code on the hardware.
 #include <ansidecl.h>
 #include <ctype.h>
 #include <limits.h>
+#include <byteswap.h>
 #include <math.h>
 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
@@ -1342,6 +1343,60 @@ sim_monitor (SIM_DESC sd,
 	break;
       }
 
+    case 13: /* int unlink(const char *path) */
+      {
+	char *path = fetch_str (sd, A0);
+	V0 = sim_io_unlink (sd, path);
+	free (path);
+	break;
+      }
+
+    case 14: /* int lseek(int fd, int offset, int whence) */
+      {
+	V0 = sim_io_lseek (sd, A0, A1, A2);
+	break;
+      }
+
+/* We may need to swap stat data around before passing it on to the
+   program being run.  */
+#define copy16(x) (BigEndianMem ? bswap_16(x) : (x))
+#define copy32(x) (BigEndianMem ? bswap_32(x) : (x))
+
+    case 15: /* int stat(const char *path, struct stat *buf); */
+      {
+	/* We need to put the data into the type of stat structure
+	   that MIPS uses and make sure it has the correct endianness.
+	   We are assuming that the host and MIPS agree on what the bits
+	   in st_mode mean.  That appears to be true for x86 linux and
+	   MIPS.  */
+        struct stat host_stat;
+	struct __attribute__ ((__packed__)) mips_stat {
+		short st_dev;
+		unsigned short st_ino;
+		unsigned int st_mode;
+		unsigned short st_nlink;
+		unsigned short st_uid;
+		unsigned short st_gid;
+		short st_rdev;
+		int st_size;
+	} mips_stat;
+	char *buf;
+        char *path = fetch_str (sd, A0);
+	buf = (char *) A1;
+	V0 = sim_io_stat (sd, path, &host_stat);
+	free (path);
+	mips_stat.st_dev = copy16((short) host_stat.st_dev);
+	mips_stat.st_ino = copy16((unsigned short) host_stat.st_ino);
+	mips_stat.st_mode = copy32((int) host_stat.st_mode);
+	mips_stat.st_nlink = copy16((unsigned short) host_stat.st_nlink);
+	mips_stat.st_uid = copy16((unsigned short) host_stat.st_uid);
+	mips_stat.st_gid = copy16((unsigned short) host_stat.st_gid);
+	mips_stat.st_rdev = copy16((short) host_stat.st_rdev);
+	mips_stat.st_size = copy32((int) host_stat.st_size);
+	sim_write (sd, A1, (char *) &mips_stat, 20);
+	break;
+      }
+
     case 17: /* void _exit() */
       {
 	sim_io_eprintf (sd, "sim_monitor(17): _exit(int reason) to be coded\n");