plink: updated to revision 10170 of putty

1 files changed, 530 insertions, 460 deletions

diff --git a/tools/plink/winmisc.c b/tools/plink/winmisc.c
index e8a35ee1d..3b57adf8f 100644
--- a/tools/plink/winmisc.c
+++ b/tools/plink/winmisc.c
@@ -1,460 +1,530 @@
-/*

- * winmisc.c: miscellaneous Windows-specific things

- */

-

-#include <stdio.h>

-#include <stdlib.h>

-#include "putty.h"

-#include <security.h>

-

-OSVERSIONINFO osVersion;

-

-char *platform_get_x_display(void) {

-    /* We may as well check for DISPLAY in case it's useful. */

-    return dupstr(getenv("DISPLAY"));

-}

-

-Filename *filename_from_str(const char *str)

-{

-    Filename *ret = snew(Filename);

-    ret->path = dupstr(str);

-    return ret;

-}

-

-Filename *filename_copy(const Filename *fn)

-{

-    return filename_from_str(fn->path);

-}

-

-const char *filename_to_str(const Filename *fn)

-{

-    return fn->path;

-}

-

-int filename_equal(const Filename *f1, const Filename *f2)

-{

-    return !strcmp(f1->path, f2->path);

-}

-

-int filename_is_null(const Filename *fn)

-{

-    return !*fn->path;

-}

-

-void filename_free(Filename *fn)

-{

-    sfree(fn->path);

-    sfree(fn);

-}

-

-int filename_serialise(const Filename *f, void *vdata)

-{

-    char *data = (char *)vdata;

-    int len = strlen(f->path) + 1;     /* include trailing NUL */

-    if (data) {

-        strcpy(data, f->path);

-    }

-    return len;

-}

-Filename *filename_deserialise(void *vdata, int maxsize, int *used)

-{

-    char *data = (char *)vdata;

-    char *end;

-    end = memchr(data, '\0', maxsize);

-    if (!end)

-        return NULL;

-    end++;

-    *used = end - data;

-    return filename_from_str(data);

-}

-

-char *get_username(void)

-{

-    DWORD namelen;

-    char *user;

-    int got_username = FALSE;

-    DECL_WINDOWS_FUNCTION(static, BOOLEAN, GetUserNameExA,

-			  (EXTENDED_NAME_FORMAT, LPSTR, PULONG));

-

-    {

-	static int tried_usernameex = FALSE;

-	if (!tried_usernameex) {

-	    /* Not available on Win9x, so load dynamically */

-	    HMODULE secur32 = load_system32_dll("secur32.dll");

-	    GET_WINDOWS_FUNCTION(secur32, GetUserNameExA);

-	    tried_usernameex = TRUE;

-	}

-    }

-

-    if (p_GetUserNameExA) {

-	/*

-	 * If available, use the principal -- this avoids the problem

-	 * that the local username is case-insensitive but Kerberos

-	 * usernames are case-sensitive.

-	 */

-

-	/* Get the length */

-	namelen = 0;

-	(void) p_GetUserNameExA(NameUserPrincipal, NULL, &namelen);

-

-	user = snewn(namelen, char);

-	got_username = p_GetUserNameExA(NameUserPrincipal, user, &namelen);

-	if (got_username) {

-	    char *p = strchr(user, '@');

-	    if (p) *p = 0;

-	} else {

-	    sfree(user);

-	}

-    }

-

-    if (!got_username) {

-	/* Fall back to local user name */

-	namelen = 0;

-	if (GetUserName(NULL, &namelen) == FALSE) {

-	    /*

-	     * Apparently this doesn't work at least on Windows XP SP2.

-	     * Thus assume a maximum of 256. It will fail again if it

-	     * doesn't fit.

-	     */

-	    namelen = 256;

-	}

-

-	user = snewn(namelen, char);

-	got_username = GetUserName(user, &namelen);

-	if (!got_username) {

-	    sfree(user);

-	}

-    }

-

-    return got_username ? user : NULL;

-}

-

-BOOL init_winver(void)

-{

-    ZeroMemory(&osVersion, sizeof(osVersion));

-    osVersion.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);

-    return GetVersionEx ( (OSVERSIONINFO *) &osVersion);

-}

-

-HMODULE load_system32_dll(const char *libname)

-{

-    /*

-     * Wrapper function to load a DLL out of c:\windows\system32

-     * without going through the full DLL search path. (Hence no

-     * attack is possible by placing a substitute DLL earlier on that

-     * path.)

-     */

-    static char *sysdir = NULL;

-    char *fullpath;

-    HMODULE ret;

-

-    if (!sysdir) {

-	int size = 0, len;

-	do {

-	    size = 3*size/2 + 512;

-	    sysdir = sresize(sysdir, size, char);

-	    len = GetSystemDirectory(sysdir, size);

-	} while (len >= size);

-    }

-

-    fullpath = dupcat(sysdir, "\\", libname, NULL);

-    ret = LoadLibrary(fullpath);

-    sfree(fullpath);

-    return ret;

-}

-

-#ifdef DEBUG

-static FILE *debug_fp = NULL;

-static HANDLE debug_hdl = INVALID_HANDLE_VALUE;

-static int debug_got_console = 0;

-

-void dputs(char *buf)

-{

-    DWORD dw;

-

-    if (!debug_got_console) {

-	if (AllocConsole()) {

-	    debug_got_console = 1;

-	    debug_hdl = GetStdHandle(STD_OUTPUT_HANDLE);

-	}

-    }

-    if (!debug_fp) {

-	debug_fp = fopen("debug.log", "w");

-    }

-

-    if (debug_hdl != INVALID_HANDLE_VALUE) {

-	WriteFile(debug_hdl, buf, strlen(buf), &dw, NULL);

-    }

-    fputs(buf, debug_fp);

-    fflush(debug_fp);

-}

-#endif

-

-#ifdef MINEFIELD

-/*

- * Minefield - a Windows equivalent for Electric Fence

- */

-

-#define PAGESIZE 4096

-

-/*

- * Design:

- * 

- * We start by reserving as much virtual address space as Windows

- * will sensibly (or not sensibly) let us have. We flag it all as

- * invalid memory.

- * 

- * Any allocation attempt is satisfied by committing one or more

- * pages, with an uncommitted page on either side. The returned

- * memory region is jammed up against the _end_ of the pages.

- * 

- * Freeing anything causes instantaneous decommitment of the pages

- * involved, so stale pointers are caught as soon as possible.

- */

-

-static int minefield_initialised = 0;

-static void *minefield_region = NULL;

-static long minefield_size = 0;

-static long minefield_npages = 0;

-static long minefield_curpos = 0;

-static unsigned short *minefield_admin = NULL;

-static void *minefield_pages = NULL;

-

-static void minefield_admin_hide(int hide)

-{

-    int access = hide ? PAGE_NOACCESS : PAGE_READWRITE;

-    VirtualProtect(minefield_admin, minefield_npages * 2, access, NULL);

-}

-

-static void minefield_init(void)

-{

-    int size;

-    int admin_size;

-    int i;

-

-    for (size = 0x40000000; size > 0; size = ((size >> 3) * 7) & ~0xFFF) {

-	minefield_region = VirtualAlloc(NULL, size,

-					MEM_RESERVE, PAGE_NOACCESS);

-	if (minefield_region)

-	    break;

-    }

-    minefield_size = size;

-

-    /*

-     * Firstly, allocate a section of that to be the admin block.

-     * We'll need a two-byte field for each page.

-     */

-    minefield_admin = minefield_region;

-    minefield_npages = minefield_size / PAGESIZE;

-    admin_size = (minefield_npages * 2 + PAGESIZE - 1) & ~(PAGESIZE - 1);

-    minefield_npages = (minefield_size - admin_size) / PAGESIZE;

-    minefield_pages = (char *) minefield_region + admin_size;

-

-    /*

-     * Commit the admin region.

-     */

-    VirtualAlloc(minefield_admin, minefield_npages * 2,

-		 MEM_COMMIT, PAGE_READWRITE);

-

-    /*

-     * Mark all pages as unused (0xFFFF).

-     */

-    for (i = 0; i < minefield_npages; i++)

-	minefield_admin[i] = 0xFFFF;

-

-    /*

-     * Hide the admin region.

-     */

-    minefield_admin_hide(1);

-

-    minefield_initialised = 1;

-}

-

-static void minefield_bomb(void)

-{

-    div(1, *(int *) minefield_pages);

-}

-

-static void *minefield_alloc(int size)

-{

-    int npages;

-    int pos, lim, region_end, region_start;

-    int start;

-    int i;

-

-    npages = (size + PAGESIZE - 1) / PAGESIZE;

-

-    minefield_admin_hide(0);

-

-    /*

-     * Search from current position until we find a contiguous

-     * bunch of npages+2 unused pages.

-     */

-    pos = minefield_curpos;

-    lim = minefield_npages;

-    while (1) {

-	/* Skip over used pages. */

-	while (pos < lim && minefield_admin[pos] != 0xFFFF)

-	    pos++;

-	/* Count unused pages. */

-	start = pos;

-	while (pos < lim && pos - start < npages + 2 &&

-	       minefield_admin[pos] == 0xFFFF)

-	    pos++;

-	if (pos - start == npages + 2)

-	    break;

-	/* If we've reached the limit, reset the limit or stop. */

-	if (pos >= lim) {

-	    if (lim == minefield_npages) {

-		/* go round and start again at zero */

-		lim = minefield_curpos;

-		pos = 0;

-	    } else {

-		minefield_admin_hide(1);

-		return NULL;

-	    }

-	}

-    }

-

-    minefield_curpos = pos - 1;

-

-    /*

-     * We have npages+2 unused pages starting at start. We leave

-     * the first and last of these alone and use the rest.

-     */

-    region_end = (start + npages + 1) * PAGESIZE;

-    region_start = region_end - size;

-    /* FIXME: could align here if we wanted */

-

-    /*

-     * Update the admin region.

-     */

-    for (i = start + 2; i < start + npages + 1; i++)

-	minefield_admin[i] = 0xFFFE;   /* used but no region starts here */

-    minefield_admin[start + 1] = region_start % PAGESIZE;

-

-    minefield_admin_hide(1);

-

-    VirtualAlloc((char *) minefield_pages + region_start, size,

-		 MEM_COMMIT, PAGE_READWRITE);

-    return (char *) minefield_pages + region_start;

-}

-

-static void minefield_free(void *ptr)

-{

-    int region_start, i, j;

-

-    minefield_admin_hide(0);

-

-    region_start = (char *) ptr - (char *) minefield_pages;

-    i = region_start / PAGESIZE;

-    if (i < 0 || i >= minefield_npages ||

-	minefield_admin[i] != region_start % PAGESIZE)

-	minefield_bomb();

-    for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++) {

-	minefield_admin[j] = 0xFFFF;

-    }

-

-    VirtualFree(ptr, j * PAGESIZE - region_start, MEM_DECOMMIT);

-

-    minefield_admin_hide(1);

-}

-

-static int minefield_get_size(void *ptr)

-{

-    int region_start, i, j;

-

-    minefield_admin_hide(0);

-

-    region_start = (char *) ptr - (char *) minefield_pages;

-    i = region_start / PAGESIZE;

-    if (i < 0 || i >= minefield_npages ||

-	minefield_admin[i] != region_start % PAGESIZE)

-	minefield_bomb();

-    for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++);

-

-    minefield_admin_hide(1);

-

-    return j * PAGESIZE - region_start;

-}

-

-void *minefield_c_malloc(size_t size)

-{

-    if (!minefield_initialised)

-	minefield_init();

-    return minefield_alloc(size);

-}

-

-void minefield_c_free(void *p)

-{

-    if (!minefield_initialised)

-	minefield_init();

-    minefield_free(p);

-}

-

-/*

- * realloc _always_ moves the chunk, for rapid detection of code

- * that assumes it won't.

- */

-void *minefield_c_realloc(void *p, size_t size)

-{

-    size_t oldsize;

-    void *q;

-    if (!minefield_initialised)

-	minefield_init();

-    q = minefield_alloc(size);

-    oldsize = minefield_get_size(p);

-    memcpy(q, p, (oldsize < size ? oldsize : size));

-    minefield_free(p);

-    return q;

-}

-

-#endif				/* MINEFIELD */

-

-FontSpec *fontspec_new(const char *name,

-                        int bold, int height, int charset)

-{

-    FontSpec *f = snew(FontSpec);

-    f->name = dupstr(name);

-    f->isbold = bold;

-    f->height = height;

-    f->charset = charset;

-    return f;

-}

-FontSpec *fontspec_copy(const FontSpec *f)

-{

-    return fontspec_new(f->name, f->isbold, f->height, f->charset);

-}

-void fontspec_free(FontSpec *f)

-{

-    sfree(f->name);

-    sfree(f);

-}

-int fontspec_serialise(FontSpec *f, void *vdata)

-{

-    char *data = (char *)vdata;

-    int len = strlen(f->name) + 1;     /* include trailing NUL */

-    if (data) {

-        strcpy(data, f->name);

-        PUT_32BIT_MSB_FIRST(data + len, f->isbold);

-        PUT_32BIT_MSB_FIRST(data + len + 4, f->height);

-        PUT_32BIT_MSB_FIRST(data + len + 8, f->charset);

-    }

-    return len + 12;                   /* also include three 4-byte ints */

-}

-FontSpec *fontspec_deserialise(void *vdata, int maxsize, int *used)

-{

-    char *data = (char *)vdata;

-    char *end;

-    if (maxsize < 13)

-        return NULL;

-    end = memchr(data, '\0', maxsize-12);

-    if (!end)

-        return NULL;

-    end++;

-    *used = end - data + 12;

-    return fontspec_new(data,

-                        GET_32BIT_MSB_FIRST(end),

-                        GET_32BIT_MSB_FIRST(end + 4),

-                        GET_32BIT_MSB_FIRST(end + 8));

-}

+/*
+ * winmisc.c: miscellaneous Windows-specific things
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "putty.h"
+#include <security.h>
+
+OSVERSIONINFO osVersion;
+
+char *platform_get_x_display(void) {
+    /* We may as well check for DISPLAY in case it's useful. */
+    return dupstr(getenv("DISPLAY"));
+}
+
+Filename *filename_from_str(const char *str)
+{
+    Filename *ret = snew(Filename);
+    ret->path = dupstr(str);
+    return ret;
+}
+
+Filename *filename_copy(const Filename *fn)
+{
+    return filename_from_str(fn->path);
+}
+
+const char *filename_to_str(const Filename *fn)
+{
+    return fn->path;
+}
+
+int filename_equal(const Filename *f1, const Filename *f2)
+{
+    return !strcmp(f1->path, f2->path);
+}
+
+int filename_is_null(const Filename *fn)
+{
+    return !*fn->path;
+}
+
+void filename_free(Filename *fn)
+{
+    sfree(fn->path);
+    sfree(fn);
+}
+
+int filename_serialise(const Filename *f, void *vdata)
+{
+    char *data = (char *)vdata;
+    int len = strlen(f->path) + 1;     /* include trailing NUL */
+    if (data) {
+        strcpy(data, f->path);
+    }
+    return len;
+}
+Filename *filename_deserialise(void *vdata, int maxsize, int *used)
+{
+    char *data = (char *)vdata;
+    char *end;
+    end = memchr(data, '\0', maxsize);
+    if (!end)
+        return NULL;
+    end++;
+    *used = end - data;
+    return filename_from_str(data);
+}
+
+#ifndef NO_SECUREZEROMEMORY
+/*
+ * Windows implementation of smemclr (see misc.c) using SecureZeroMemory.
+ */
+void smemclr(void *b, size_t n) {
+    if (b && n > 0)
+        SecureZeroMemory(b, n);
+}
+#endif
+
+char *get_username(void)
+{
+    DWORD namelen;
+    char *user;
+    int got_username = FALSE;
+    DECL_WINDOWS_FUNCTION(static, BOOLEAN, GetUserNameExA,
+			  (EXTENDED_NAME_FORMAT, LPSTR, PULONG));
+
+    {
+	static int tried_usernameex = FALSE;
+	if (!tried_usernameex) {
+	    /* Not available on Win9x, so load dynamically */
+	    HMODULE secur32 = load_system32_dll("secur32.dll");
+	    GET_WINDOWS_FUNCTION(secur32, GetUserNameExA);
+	    tried_usernameex = TRUE;
+	}
+    }
+
+    if (p_GetUserNameExA) {
+	/*
+	 * If available, use the principal -- this avoids the problem
+	 * that the local username is case-insensitive but Kerberos
+	 * usernames are case-sensitive.
+	 */
+
+	/* Get the length */
+	namelen = 0;
+	(void) p_GetUserNameExA(NameUserPrincipal, NULL, &namelen);
+
+	user = snewn(namelen, char);
+	got_username = p_GetUserNameExA(NameUserPrincipal, user, &namelen);
+	if (got_username) {
+	    char *p = strchr(user, '@');
+	    if (p) *p = 0;
+	} else {
+	    sfree(user);
+	}
+    }
+
+    if (!got_username) {
+	/* Fall back to local user name */
+	namelen = 0;
+	if (GetUserName(NULL, &namelen) == FALSE) {
+	    /*
+	     * Apparently this doesn't work at least on Windows XP SP2.
+	     * Thus assume a maximum of 256. It will fail again if it
+	     * doesn't fit.
+	     */
+	    namelen = 256;
+	}
+
+	user = snewn(namelen, char);
+	got_username = GetUserName(user, &namelen);
+	if (!got_username) {
+	    sfree(user);
+	}
+    }
+
+    return got_username ? user : NULL;
+}
+
+BOOL init_winver(void)
+{
+    ZeroMemory(&osVersion, sizeof(osVersion));
+    osVersion.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
+    return GetVersionEx ( (OSVERSIONINFO *) &osVersion);
+}
+
+HMODULE load_system32_dll(const char *libname)
+{
+    /*
+     * Wrapper function to load a DLL out of c:\windows\system32
+     * without going through the full DLL search path. (Hence no
+     * attack is possible by placing a substitute DLL earlier on that
+     * path.)
+     */
+    static char *sysdir = NULL;
+    char *fullpath;
+    HMODULE ret;
+
+    if (!sysdir) {
+	int size = 0, len;
+	do {
+	    size = 3*size/2 + 512;
+	    sysdir = sresize(sysdir, size, char);
+	    len = GetSystemDirectory(sysdir, size);
+	} while (len >= size);
+    }
+
+    fullpath = dupcat(sysdir, "\\", libname, NULL);
+    ret = LoadLibrary(fullpath);
+    sfree(fullpath);
+    return ret;
+}
+
+/*
+ * A tree234 containing mappings from system error codes to strings.
+ */
+
+struct errstring {
+    int error;
+    char *text;
+};
+
+static int errstring_find(void *av, void *bv)
+{
+    int *a = (int *)av;
+    struct errstring *b = (struct errstring *)bv;
+    if (*a < b->error)
+        return -1;
+    if (*a > b->error)
+        return +1;
+    return 0;
+}
+static int errstring_compare(void *av, void *bv)
+{
+    struct errstring *a = (struct errstring *)av;
+    return errstring_find(&a->error, bv);
+}
+
+static tree234 *errstrings = NULL;
+
+const char *win_strerror(int error)
+{
+    struct errstring *es;
+
+    if (!errstrings)
+        errstrings = newtree234(errstring_compare);
+
+    es = find234(errstrings, &error, errstring_find);
+
+    if (!es) {
+        char msgtext[65536]; /* maximum size for FormatMessage is 64K */
+
+        es = snew(struct errstring);
+        es->error = error;
+        if (!FormatMessage((FORMAT_MESSAGE_FROM_SYSTEM |
+                            FORMAT_MESSAGE_IGNORE_INSERTS), NULL, error,
+                           MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                           msgtext, lenof(msgtext)-1, NULL)) {
+            sprintf(msgtext,
+                    "(unable to format: FormatMessage returned %d)", 
+                    error, GetLastError());
+        } else {
+            int len = strlen(msgtext);
+            if (len > 0 && msgtext[len-1] == '\n')
+                msgtext[len-1] = '\0';
+        }
+        es->text = dupprintf("Error %d: %s", error, msgtext);
+        add234(errstrings, es);
+    }
+
+    return es->text;
+}
+
+#ifdef DEBUG
+static FILE *debug_fp = NULL;
+static HANDLE debug_hdl = INVALID_HANDLE_VALUE;
+static int debug_got_console = 0;
+
+void dputs(char *buf)
+{
+    DWORD dw;
+
+    if (!debug_got_console) {
+	if (AllocConsole()) {
+	    debug_got_console = 1;
+	    debug_hdl = GetStdHandle(STD_OUTPUT_HANDLE);
+	}
+    }
+    if (!debug_fp) {
+	debug_fp = fopen("debug.log", "w");
+    }
+
+    if (debug_hdl != INVALID_HANDLE_VALUE) {
+	WriteFile(debug_hdl, buf, strlen(buf), &dw, NULL);
+    }
+    fputs(buf, debug_fp);
+    fflush(debug_fp);
+}
+#endif
+
+#ifdef MINEFIELD
+/*
+ * Minefield - a Windows equivalent for Electric Fence
+ */
+
+#define PAGESIZE 4096
+
+/*
+ * Design:
+ * 
+ * We start by reserving as much virtual address space as Windows
+ * will sensibly (or not sensibly) let us have. We flag it all as
+ * invalid memory.
+ * 
+ * Any allocation attempt is satisfied by committing one or more
+ * pages, with an uncommitted page on either side. The returned
+ * memory region is jammed up against the _end_ of the pages.
+ * 
+ * Freeing anything causes instantaneous decommitment of the pages
+ * involved, so stale pointers are caught as soon as possible.
+ */
+
+static int minefield_initialised = 0;
+static void *minefield_region = NULL;
+static long minefield_size = 0;
+static long minefield_npages = 0;
+static long minefield_curpos = 0;
+static unsigned short *minefield_admin = NULL;
+static void *minefield_pages = NULL;
+
+static void minefield_admin_hide(int hide)
+{
+    int access = hide ? PAGE_NOACCESS : PAGE_READWRITE;
+    VirtualProtect(minefield_admin, minefield_npages * 2, access, NULL);
+}
+
+static void minefield_init(void)
+{
+    int size;
+    int admin_size;
+    int i;
+
+    for (size = 0x40000000; size > 0; size = ((size >> 3) * 7) & ~0xFFF) {
+	minefield_region = VirtualAlloc(NULL, size,
+					MEM_RESERVE, PAGE_NOACCESS);
+	if (minefield_region)
+	    break;
+    }
+    minefield_size = size;
+
+    /*
+     * Firstly, allocate a section of that to be the admin block.
+     * We'll need a two-byte field for each page.
+     */
+    minefield_admin = minefield_region;
+    minefield_npages = minefield_size / PAGESIZE;
+    admin_size = (minefield_npages * 2 + PAGESIZE - 1) & ~(PAGESIZE - 1);
+    minefield_npages = (minefield_size - admin_size) / PAGESIZE;
+    minefield_pages = (char *) minefield_region + admin_size;
+
+    /*
+     * Commit the admin region.
+     */
+    VirtualAlloc(minefield_admin, minefield_npages * 2,
+		 MEM_COMMIT, PAGE_READWRITE);
+
+    /*
+     * Mark all pages as unused (0xFFFF).
+     */
+    for (i = 0; i < minefield_npages; i++)
+	minefield_admin[i] = 0xFFFF;
+
+    /*
+     * Hide the admin region.
+     */
+    minefield_admin_hide(1);
+
+    minefield_initialised = 1;
+}
+
+static void minefield_bomb(void)
+{
+    div(1, *(int *) minefield_pages);
+}
+
+static void *minefield_alloc(int size)
+{
+    int npages;
+    int pos, lim, region_end, region_start;
+    int start;
+    int i;
+
+    npages = (size + PAGESIZE - 1) / PAGESIZE;
+
+    minefield_admin_hide(0);
+
+    /*
+     * Search from current position until we find a contiguous
+     * bunch of npages+2 unused pages.
+     */
+    pos = minefield_curpos;
+    lim = minefield_npages;
+    while (1) {
+	/* Skip over used pages. */
+	while (pos < lim && minefield_admin[pos] != 0xFFFF)
+	    pos++;
+	/* Count unused pages. */
+	start = pos;
+	while (pos < lim && pos - start < npages + 2 &&
+	       minefield_admin[pos] == 0xFFFF)
+	    pos++;
+	if (pos - start == npages + 2)
+	    break;
+	/* If we've reached the limit, reset the limit or stop. */
+	if (pos >= lim) {
+	    if (lim == minefield_npages) {
+		/* go round and start again at zero */
+		lim = minefield_curpos;
+		pos = 0;
+	    } else {
+		minefield_admin_hide(1);
+		return NULL;
+	    }
+	}
+    }
+
+    minefield_curpos = pos - 1;
+
+    /*
+     * We have npages+2 unused pages starting at start. We leave
+     * the first and last of these alone and use the rest.
+     */
+    region_end = (start + npages + 1) * PAGESIZE;
+    region_start = region_end - size;
+    /* FIXME: could align here if we wanted */
+
+    /*
+     * Update the admin region.
+     */
+    for (i = start + 2; i < start + npages + 1; i++)
+	minefield_admin[i] = 0xFFFE;   /* used but no region starts here */
+    minefield_admin[start + 1] = region_start % PAGESIZE;
+
+    minefield_admin_hide(1);
+
+    VirtualAlloc((char *) minefield_pages + region_start, size,
+		 MEM_COMMIT, PAGE_READWRITE);
+    return (char *) minefield_pages + region_start;
+}
+
+static void minefield_free(void *ptr)
+{
+    int region_start, i, j;
+
+    minefield_admin_hide(0);
+
+    region_start = (char *) ptr - (char *) minefield_pages;
+    i = region_start / PAGESIZE;
+    if (i < 0 || i >= minefield_npages ||
+	minefield_admin[i] != region_start % PAGESIZE)
+	minefield_bomb();
+    for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++) {
+	minefield_admin[j] = 0xFFFF;
+    }
+
+    VirtualFree(ptr, j * PAGESIZE - region_start, MEM_DECOMMIT);
+
+    minefield_admin_hide(1);
+}
+
+static int minefield_get_size(void *ptr)
+{
+    int region_start, i, j;
+
+    minefield_admin_hide(0);
+
+    region_start = (char *) ptr - (char *) minefield_pages;
+    i = region_start / PAGESIZE;
+    if (i < 0 || i >= minefield_npages ||
+	minefield_admin[i] != region_start % PAGESIZE)
+	minefield_bomb();
+    for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++);
+
+    minefield_admin_hide(1);
+
+    return j * PAGESIZE - region_start;
+}
+
+void *minefield_c_malloc(size_t size)
+{
+    if (!minefield_initialised)
+	minefield_init();
+    return minefield_alloc(size);
+}
+
+void minefield_c_free(void *p)
+{
+    if (!minefield_initialised)
+	minefield_init();
+    minefield_free(p);
+}
+
+/*
+ * realloc _always_ moves the chunk, for rapid detection of code
+ * that assumes it won't.
+ */
+void *minefield_c_realloc(void *p, size_t size)
+{
+    size_t oldsize;
+    void *q;
+    if (!minefield_initialised)
+	minefield_init();
+    q = minefield_alloc(size);
+    oldsize = minefield_get_size(p);
+    memcpy(q, p, (oldsize < size ? oldsize : size));
+    minefield_free(p);
+    return q;
+}
+
+#endif				/* MINEFIELD */
+
+FontSpec *fontspec_new(const char *name,
+                        int bold, int height, int charset)
+{
+    FontSpec *f = snew(FontSpec);
+    f->name = dupstr(name);
+    f->isbold = bold;
+    f->height = height;
+    f->charset = charset;
+    return f;
+}
+FontSpec *fontspec_copy(const FontSpec *f)
+{
+    return fontspec_new(f->name, f->isbold, f->height, f->charset);
+}
+void fontspec_free(FontSpec *f)
+{
+    sfree(f->name);
+    sfree(f);
+}
+int fontspec_serialise(FontSpec *f, void *vdata)
+{
+    char *data = (char *)vdata;
+    int len = strlen(f->name) + 1;     /* include trailing NUL */
+    if (data) {
+        strcpy(data, f->name);
+        PUT_32BIT_MSB_FIRST(data + len, f->isbold);
+        PUT_32BIT_MSB_FIRST(data + len + 4, f->height);
+        PUT_32BIT_MSB_FIRST(data + len + 8, f->charset);
+    }
+    return len + 12;                   /* also include three 4-byte ints */
+}
+FontSpec *fontspec_deserialise(void *vdata, int maxsize, int *used)
+{
+    char *data = (char *)vdata;
+    char *end;
+    if (maxsize < 13)
+        return NULL;
+    end = memchr(data, '\0', maxsize-12);
+    if (!end)
+        return NULL;
+    end++;
+    *used = end - data + 12;
+    return fontspec_new(data,
+                        GET_32BIT_MSB_FIRST(end),
+                        GET_32BIT_MSB_FIRST(end + 4),
+                        GET_32BIT_MSB_FIRST(end + 8));
+}