win32: ash: forkshell_prepare()

1 files changed, 70 insertions, 0 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 4710f7153..6a1e78e19 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -13172,6 +13172,14 @@ static short profile_buf[16384];
 extern int etext();
 #endif
 
+#if ENABLE_PLATFORM_MINGW32
+static const forkpoint_fn forkpoints[] = {
+        NULL
+};
+
+static struct forkshell* forkshell_prepare(struct forkshell *fs);
+#endif
+
 /*
  * Main routine.  We initialize things, parse the arguments, execute
  * profiles if we're a login shell, and then call cmdloop to execute
@@ -13315,6 +13323,16 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
 
 /*
  * forkshell_prepare() and friends
+ *
+ * The sequence is as follows:
+ * - funcblocksize, funcstringsize, nodeptrsize are initialized
+ * - forkshell_size(fs) is called to calculate the exact memory needed
+ * - a new struct is allocated
+ * - funcblock, funcstring, nodeptr are initialized from the new block
+ * - forkshell_copy(fs) is called to copy recursively everything over
+ *   it will record all pointers along the way, to nodeptr
+ *
+ * When this memory is mapped elsewhere, pointer fixup will be needed
  */
 #define SLIST_SIZE_BEGIN(name,type) \
 static void \
@@ -13676,6 +13694,58 @@ forkshell_copy(struct forkshell *fs)
         SAVE_PTR4(new->n, new->argv, new->string, new->strlist);
         return new;
 }
+
+static struct forkshell *
+forkshell_prepare(struct forkshell *fs)
+{
+        struct forkshell *new;
+        int size, fp, nodeptr_offset;
+        HANDLE h;
+        SECURITY_ATTRIBUTES sa;
+
+        for (fp = 0; forkpoints[fp] && forkpoints[fp] != fs->fp; fp++)
+                ;
+
+        if (!forkpoints[fp])
+                bb_error_msg_and_die("invalid forkpoint %08x", (int)fs->fp);
+        fs->fpid = fp;
+
+        /* Calculate size of "new" */
+        fs->gvp = ash_ptr_to_globals_var;
+        fs->gmp = ash_ptr_to_globals_misc;
+        fs->cmdtable = cmdtable;
+        fs->localvars = localvars;
+
+        nodeptrsize = 1;        /* NULL terminated */
+        funcblocksize = 0;
+        funcstringsize = 0;
+        forkshell_size(fs);
+        size = funcblocksize + funcstringsize + nodeptrsize*sizeof(int);
+
+        /* Allocate, initialize pointers */
+        memset(&sa, 0, sizeof(sa));
+        sa.nLength = sizeof(sa);
+        sa.lpSecurityDescriptor = NULL;
+        sa.bInheritHandle = TRUE;
+        h = CreateFileMapping(INVALID_HANDLE_VALUE, &sa, PAGE_READWRITE, 0, size, NULL);
+        new = (struct forkshell *)MapViewOfFile(h, FILE_MAP_WRITE, 0,0, 0);
+        /* new = ckmalloc(size); */
+        funcblock = new;
+        funcstring = (char *) funcblock + funcblocksize;
+        nodeptr = (int*)((char *) funcstring + funcstringsize);
+        nodeptr_offset = (int) nodeptr - (int) new;
+
+        /* Now pack them all */
+        forkshell_copy(fs);
+
+        /* Finish it up */
+        *nodeptr = 0;
+        new->size = size;
+        new->nodeptr_offset = nodeptr_offset;
+        new->old_base = new;
+        new->hMapFile = h;
+        return new;
+}
 /*-
  * Copyright (c) 1989, 1991, 1993, 1994
  *      The Regents of the University of California.  All rights reserved.