Re: [PATCH] sim: mips: Add handlers to simulator monitor for unlink, lseek and stat

[Faraz Shahbazker <fshahbazker@wavecomp.com>]

Tagging global maintainers.
________________________________
From: Faraz Shahbazker <fshahbazker@wavecomp.com>
Sent: Sunday, March 28, 2021 2:32 AM
To: gdb-patches@sourceware.org <gdb-patches@sourceware.org>
Cc: Faraz Shahbazker <fshahbazker@wavecomp.com>; Chao-ying Fu <cfu@wavecomp.com>
Subject: [PATCH] sim: mips: Add handlers to simulator monitor for unlink, lseek and stat

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

Derived from patch authored by Steve Ellcey <sellcey@mips.com>
---
 sim/mips/ChangeLog |  6 +++++
 sim/mips/interp.c  | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/sim/mips/ChangeLog b/sim/mips/ChangeLog
index 12347a7..88dd7dc 100644
--- a/sim/mips/ChangeLog
+++ b/sim/mips/ChangeLog
@@ -1,3 +1,9 @@
+2021-03-28  Steve Ellcey  <sellcey@mips.com>
+           Faraz Shahbazker  <fshahbazker@wavecomp.com>
+
+       * interp.c (sim_monitor): Add switch entries for unlink (13),
+       lseek (14), and stat (15).
+
 2021-02-28  Mike Frysinger  <vapier@gentoo.org>

         * configure: Regenerate.
diff --git a/sim/mips/interp.c b/sim/mips/interp.c
index fd93a12..13e9129 100644
--- a/sim/mips/interp.c
+++ b/sim/mips/interp.c
@@ -40,6 +40,7 @@ code on the hardware.
 #include <ansidecl.h>
 #include <ctype.h>
 #include <limits.h>
+#include <byteswap.h>
 #include <math.h>
 #include <stdlib.h>
 #include <string.h>
@@ -1167,7 +1168,7 @@ sim_monitor (SIM_DESC sd,

   /* The following callback functions are available, however the
      monitor we are simulating does not make use of them: get_errno,
-     isatty, lseek, rename, system, time and unlink */
+     isatty, rename, system and time.  */
   switch (reason)
     {

@@ -1241,6 +1242,71 @@ 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))
+#define copy64(x) (BigEndianMem ? bswap_64 (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;
+         union {
+           int b32;
+           long b64;
+         } st_size;
+       } mips_stat;
+       char *buf;
+       char *path = fetch_str (sd, A0);
+       bfd *prog_bfd = STATE_PROG_BFD (sd);
+       int is_elf32bit = (elf_elfheader(prog_bfd)->e_ident[EI_CLASS] ==
+                          ELFCLASS32);
+       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);
+       if (is_elf32bit)
+         mips_stat.st_size.b32 = copy32 ((int) host_stat.st_size);
+       else
+         mips_stat.st_size.b64 = copy64 ((long) host_stat.st_size);
+       sim_write (sd, A1, (char *) &mips_stat,
+                  sizeof(mips_stat) - (is_elf32bit? 4 : 0));
+       break;
+      }
+
     case 17: /* void _exit() */
       {
         sim_io_eprintf (sd, "sim_monitor(17): _exit(int reason) to be coded\n");
--
2.9.5