Date:	Thu, 19 Jun 1997 15:29:34 +0200 (METDST)
From:	Robert Hoehne <robert DOT hoehne AT mathematik DOT tu-chemnitz DOT de>
To:	DJGPP workers <djgpp-workers AT delorie DOT com>
Subject:	symlink patch (2/6)
Message-Id:	<Pine.HPP.3.95q.970619152902.4123F-100000@newton.mathematik.tu-chemnitz.de>
Mime-Version:	1.0

--- src/libc/dos/process/chkv2prg.c~	Wed Jun 18 09:57:58 1997
+++ src/libc/dos/process/chkv2prg.c	Thu Jun 19 13:43:34 1997
@@ -0,0 +1,123 @@
+/* Copyright (C) 1997 DJ Delorie, see COPYING.DJ for details */
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define STUB_INFO_MAGIC "StubInfoMagic!!"
+
+static _v2_prog_type type;
+static int type_initialized = 0;
+
+const _v2_prog_type *_check_v2_prog(const char *program, int pf)
+{
+  unsigned short header[5];
+
+  if (type_initialized && type.stubinfo)
+    free(type.stubinfo);
+  type_initialized = 1;
+
+  memset(&type, 0, sizeof(type));
+
+  if (program)
+  {
+    pf = open(program, O_RDONLY|O_BINARY);
+    if (pf < 0)
+      return &type;
+  }
+
+  lseek(pf, 0, SEEK_SET);
+  if (read(pf, header, sizeof(header)) != sizeof(header))
+    return &type;
+  if (header[0] == 0x010b || header[0] == 0x014c)
+  {
+    unsigned char firstbytes[1];
+    unsigned long coffhdr[40];
+
+    /* Seems to be an unstubbed COFF.  See what the first opcode
+       is to determine if it's v1.x or v2 COFF (or an impostor).
+
+       FIXME: the code here assumes that any COFF that's not a V1
+       can only be V2.  What about other compilers that use COFF?  */
+    type.object_format = _V2_OBJECT_FORMAT_COFF;
+    if (lseek(pf, 2, 1) < 0
+	|| read(pf, coffhdr, sizeof(coffhdr)) != sizeof(coffhdr)
+	|| lseek(pf, coffhdr[10 + 5], 0) < 0
+	|| read(pf, firstbytes, 1) != 1) /* scnptr */
+        /* "Aha! An impostor!" (The Adventure game) */
+      type.object_format = _V2_OBJECT_FORMAT_UNKNOWN;
+    else if (firstbytes[0] != 0xa3) /* opcode of movl %eax, 0x12345678 (V1) */
+           type.version.v.major = 2;
+         else
+           type.version.v.major = 1;
+    type.exec_format = _V2_EXEC_FORMAT_COFF;
+  }
+  else if (header[0] == 0x5a4d)	/* "MZ" */
+  {
+    char go32stub[9];
+    unsigned long coff_start = (unsigned long)header[2]*512L;
+    unsigned long exe_start;
+    type.exec_format = _V2_EXEC_FORMAT_EXE;
+    if (header[1])
+      coff_start += (long)header[1] - 512L;
+    exe_start = (unsigned long)header[4]*16L;
+    if (lseek(pf, exe_start, SEEK_SET) != exe_start)
+      return &type;
+    if (read(pf, go32stub, 8) != 8)
+      return &type;
+    go32stub[8] = 0;
+    if (strcmp(go32stub, "go32stub") == 0)
+    {
+      type.version.v.major = 2;
+      type.object_format = _V2_OBJECT_FORMAT_COFF;
+      type.exec_format = _V2_EXEC_FORMAT_STUBCOFF;
+    }
+    else
+    {
+      int stub_offset;
+      char magic[16];
+      int struct_length;
+      unsigned short coff_id;
+      type.version.v.major = 1;
+      if (lseek(pf, coff_start - 4, SEEK_SET) != coff_start-4)
+        return &type;
+      if (read(pf, &stub_offset, 4) != 4)
+        return &type;
+      if (read(pf, &coff_id, 2) != 2)
+        return &type;
+      if (coff_id == 0x010b || coff_id == 0x014c)
+      {
+        type.object_format = _V2_OBJECT_FORMAT_COFF;
+        type.exec_format = _V2_EXEC_FORMAT_STUBCOFF;
+      }
+      if (lseek(pf, stub_offset, 0) != stub_offset)
+        return &type;
+      if (read(pf, magic, 16) != 16)
+        return &type;
+      if (memcmp(STUB_INFO_MAGIC, magic, 16) == 0)
+      {
+        if (read(pf, &struct_length, 4) != 4)
+          return &type;
+        type.stubinfo = (_v1_stubinfo *)malloc(struct_length);
+        memcpy(type.stubinfo->magic, magic, 16);
+        type.stubinfo->struct_length = struct_length;
+        if (read(pf, type.stubinfo->go32, struct_length - 20)
+            != struct_length - 20)
+          return &type;
+        type.has_stubinfo = 1;
+      }
+    }
+  }
+  else if (header[0] == 0x2123)	/* "#!" */
+  {
+    type.exec_format = _V2_EXEC_FORMAT_UNIXSCRIPT;
+  }
+
+  if (program)
+    close(pf);
+
+  type.valid = 1;
+  return &type;
+}
+
+

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