[FREELDR] Parse NT kernel load options in a consistent manner.

HBelusca · binarymaster · commit 4406c36be3ef · 2025-11-17T22:34:12.000+01:00
- Introduce a set of NtLdrGet(Next)Option(Ex) helpers that allow
  retrieving respectively, the "next" option in an options string,
  and retrieving a given named option in such an options string,
  by correctly parsing that string.

  Valid syntaxes:
      /OPTION1 /OPTION2/OPTION3 OPTION4 /OPTION5(=...) ...

  Options separators are slashes, or whitespace (space, tab), mandatory
  if no slash is used, and otherwise optional.

- Use these functions wherever NT load options are being parsed.

- Simplify the parsing of /DEBUGPORT=... using these functions.

- When parsing the /HAL=... or /KERNEL=... options, only the first
  encountered one is taken into account, any other ones are discarded.

- When parsing the other load options, only their first occurrences are
  taken into account, any other repetitions are discarded.
  * The NOPAE option overrides any previous PAE option.
  * Any NOEXECUTE(=) option should override any previous
    NOEXECUTE=ALWAYSOFF (or equivalently, EXECUTE) option.
diff --git a/boot/freeldr/freeldr/CMakeLists.txt b/boot/freeldr/freeldr/CMakeLists.txt
@@ -224,6 +224,7 @@ list(APPEND FREELDR_BASE_SOURCE
                      ## otherwise we get linking errors with Rtl**Bitmap** APIs.
                      ## Do not happen on MSVC builds however...
     ntldr/inffile.c
+    ntldr/ntldropts.c
     lib/rtl/libsupp.c)
 
 if(ARCH STREQUAL "i386")
diff --git a/boot/freeldr/freeldr/disk/ramdisk.c b/boot/freeldr/freeldr/disk/ramdisk.c
@@ -10,6 +10,7 @@
 /* INCLUDES *******************************************************************/
 
 #include <freeldr.h>
+#include "../ntldr/ntldropts.h"
 
 /* GLOBALS ********************************************************************/
 
@@ -241,30 +242,31 @@ RamDiskInitialize(
         /* If we don't have any load options, initialize an empty Ramdisk */
         if (LoadOptions)
         {
-            PCHAR Option;
+            PCSTR Option;
+            ULONG FileNameLength;
 
             /* Ramdisk image file name */
-            Option = strstr(LoadOptions, "/RDPATH=");
-            if (Option)
+            Option = NtLdrGetOptionEx(LoadOptions, "RDPATH=", &FileNameLength);
+            if (Option && (FileNameLength > 7))
             {
-                /* Copy the file name - everything until the next separator */
-                Option += 8;
+                /* Copy the file name */
+                Option += 7; FileNameLength -= 7;
                 RtlStringCbCopyNA(FileName, sizeof(FileName),
-                                  Option, strcspn(Option, " \t") * sizeof(CHAR));
+                                  Option, FileNameLength * sizeof(CHAR));
             }
 
             /* Ramdisk image length */
-            Option = strstr(LoadOptions, "/RDIMAGELENGTH=");
+            Option = NtLdrGetOption(LoadOptions, "RDIMAGELENGTH=");
             if (Option)
             {
-                RamDiskImageLength = _atoi64(Option + 15);
+                RamDiskImageLength = _atoi64(Option + 14);
             }
 
             /* Ramdisk image offset */
-            Option = strstr(LoadOptions, "/RDIMAGEOFFSET=");
+            Option = NtLdrGetOption(LoadOptions, "RDIMAGEOFFSET=");
             if (Option)
             {
-                RamDiskImageOffset = atol(Option + 15);
+                RamDiskImageOffset = atol(Option + 14);
             }
         }
 
diff --git a/boot/freeldr/freeldr/ntldr/ntldropts.c b/boot/freeldr/freeldr/ntldr/ntldropts.c
@@ -0,0 +1,131 @@
+/*
+ * PROJECT:     FreeLoader
+ * LICENSE:     GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
+ * PURPOSE:     NT Kernel Load Options Support Functions
+ * COPYRIGHT:   Copyright 2020 Hermes Belusca-Maito
+ */
+
+/* INCLUDES ******************************************************************/
+
+#include <freeldr.h>
+#include "ntldropts.h"
+
+/* FUNCTIONS *****************************************************************/
+
+PCSTR
+NtLdrGetNextOption(
+    IN OUT PCSTR* Options,
+    OUT PULONG OptionLength OPTIONAL)
+{
+    PCSTR NextOption;
+    PCSTR Option = NULL;
+    ULONG Length = 0;
+
+    if (OptionLength)
+        *OptionLength = 0;
+
+    if (!Options || !*Options)
+        return NULL;
+
+    /* Loop over each option */
+    NextOption = *Options;
+    while (*NextOption)
+    {
+        /* Skip possible initial whitespace */
+        NextOption += strspn(NextOption, " \t");
+
+        /* Stop now if we have already found an option.
+         * NextOption points to the next following option. */
+        if (Option)
+            break;
+
+        /*
+         * Check whether a new option starts. Options are delimited
+         * with an option separator '/' or with whitespace.
+         */
+        if (*NextOption == '/')
+            ++NextOption;
+
+        /* Get the actual length of the option until
+         * the next whitespace or option separator. */
+        Length = (ULONG)strcspn(NextOption, " \t/");
+
+        /* Retrieve the option if present and go to the beginning of the next one */
+        if (Length != 0)
+            Option = NextOption;
+
+        /* Restart after the end of the option */
+        NextOption += Length;
+    }
+
+    *Options = NextOption;
+    if (Option && OptionLength)
+        *OptionLength = Length;
+    return Option;
+}
+
+/*
+ * OptionName specifies the option name, without any leading
+ * option separator '/', to search for within the Options.
+ * The search is made case-insensitive.
+ */
+PCSTR
+NtLdrGetOptionExN(
+    IN PCSTR Options,
+    IN PCCH OptionName,
+    IN ULONG OptNameLength,
+    OUT PULONG OptionLength OPTIONAL)
+{
+    PCSTR NextOptions;
+    PCSTR Option = NULL;
+    ULONG OptLength = 0;
+
+    if (OptionLength)
+        *OptionLength = 0;
+
+    if (!Options || !*Options)
+        return NULL;
+    if (!OptionName || (OptNameLength == 0) || !*OptionName)
+        return NULL;
+
+    NextOptions = Options;
+    while ((Option = NtLdrGetNextOption(&NextOptions, &OptLength)))
+    {
+        /*
+         * Check whether the option to find exactly matches the current
+         * load option, or is a prefix thereof if this is an option with
+         * appended data.
+         */
+        if ((OptLength >= OptNameLength) &&
+            (_strnicmp(Option, OptionName, OptNameLength) == 0))
+        {
+            if ((OptLength == OptNameLength) ||
+                (OptionName[OptNameLength-1] == '=') ||
+                (OptionName[OptNameLength-1] == ':'))
+            {
+                break;
+            }
+        }
+    }
+
+    if (Option && OptionLength)
+        *OptionLength = OptLength;
+    return Option;
+}
+
+PCSTR
+NtLdrGetOptionEx(
+    IN PCSTR Options,
+    IN PCSTR OptionName,
+    OUT PULONG OptionLength OPTIONAL)
+{
+    return NtLdrGetOptionExN(Options, OptionName, strlen(OptionName), OptionLength);
+}
+
+PCSTR
+NtLdrGetOption(
+    IN PCSTR Options,
+    IN PCSTR OptionName)
+{
+    return NtLdrGetOptionEx(Options, OptionName, NULL);
+}
diff --git a/boot/freeldr/freeldr/ntldr/ntldropts.h b/boot/freeldr/freeldr/ntldr/ntldropts.h
@@ -0,0 +1,31 @@
+/*
+ * PROJECT:     FreeLoader
+ * LICENSE:     GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
+ * PURPOSE:     NT Kernel Load Options Support Functions
+ * COPYRIGHT:   Copyright 2020 Hermes Belusca-Maito
+ */
+
+#pragma once
+
+PCSTR
+NtLdrGetNextOption(
+    IN OUT PCSTR* Options,
+    OUT PULONG OptionLength OPTIONAL);
+
+PCSTR
+NtLdrGetOptionExN(
+    IN PCSTR Options,
+    IN PCCH OptionName,
+    IN ULONG OptNameLength,
+    OUT PULONG OptionLength OPTIONAL);
+
+PCSTR
+NtLdrGetOptionEx(
+    IN PCSTR Options,
+    IN PCSTR OptionName,
+    OUT PULONG OptionLength OPTIONAL);
+
+PCSTR
+NtLdrGetOption(
+    IN PCSTR Options,
+    IN PCSTR OptionName);
diff --git a/boot/freeldr/freeldr/ntldr/setupldr.c b/boot/freeldr/freeldr/ntldr/setupldr.c
@@ -10,6 +10,7 @@
 #include <arc/setupblk.h>
 #include "winldr.h"
 #include "inffile.h"
+#include "ntldropts.h"
 
 #include <debug.h>
 DBG_DEFAULT_CHANNEL(WINDOWS);
@@ -140,6 +141,7 @@ LoadReactOSSetup(
     PCSTR SystemPartition;
     PCSTR SystemPath;
     PSTR FileName;
+    ULONG FileNameLength;
     BOOLEAN BootFromFloppy;
     BOOLEAN Success;
     HINF InfHandle;
@@ -236,16 +238,16 @@ LoadReactOSSetup(
     TRACE("BootOptions: '%s'\n", BootOptions2);
 
     /* Check if a RAM disk file was given */
-    FileName = strstr(BootOptions2, "/RDPATH=");
-    if (FileName)
+    FileName = (PSTR)NtLdrGetOptionEx(BootOptions2, "RDPATH=", &FileNameLength);
+    if (FileName && (FileNameLength > 7))
     {
         /* Load the RAM disk */
         Status = RamDiskInitialize(FALSE, BootOptions2, SystemPartition);
         if (Status != ESUCCESS)
         {
-            FileName += 8;
+            FileName += 7; FileNameLength -= 7;
             UiMessageBox("Failed to load RAM disk file '%.*s'",
-                         strcspn(FileName, " \t"), FileName);
+                         FileNameLength, FileName);
             return Status;
         }
     }
@@ -263,7 +265,8 @@ LoadReactOSSetup(
             UiMessageBox("Failed to open txtsetup.sif");
             return ENOENT;
         }
-        RtlStringCbCopyA(FileName, sizeof(BootPath) - (FileName - BootPath)*sizeof(CHAR), SystemPath);
+        FileNameLength = (ULONG)(sizeof(BootPath) - (FileName - BootPath)*sizeof(CHAR));
+        RtlStringCbCopyA(FileName, FileNameLength, SystemPath);
         RtlStringCbCopyA(FilePath, sizeof(FilePath), BootPath);
         RtlStringCbCatA(FilePath, sizeof(FilePath), "txtsetup.sif");
         if (InfOpenFile(&InfHandle, FilePath, &ErrorLine))
diff --git a/boot/freeldr/freeldr/ntldr/winldr.c b/boot/freeldr/freeldr/ntldr/winldr.c

Original file line number	Diff line number	Diff line change
`@@ -10,6 +10,7 @@`
`10`	`10`	`/* INCLUDES *******************************************************************/`
`11`	`11`
`12`	`12`	`#include <freeldr.h>`
	`13`	`+#include "../ntldr/ntldropts.h"`
`13`	`14`
`14`	`15`	`/* GLOBALS ********************************************************************/`
`15`	`16`
`@@ -241,30 +242,31 @@ RamDiskInitialize(`
`241`	`242`	`/* If we don't have any load options, initialize an empty Ramdisk */`
`242`	`243`	`if (LoadOptions)`
`243`	`244`	`{`
`244`		`- PCHAR Option;`
	`245`	`+ PCSTR Option;`
	`246`	`+ ULONG FileNameLength;`
`245`	`247`
`246`	`248`	`/* Ramdisk image file name */`
`247`		`- Option = strstr(LoadOptions, "/RDPATH=");`
`248`		`- if (Option)`
	`249`	`+ Option = NtLdrGetOptionEx(LoadOptions, "RDPATH=", &FileNameLength);`
	`250`	`+ if (Option && (FileNameLength > 7))`
`249`	`251`	`{`
`250`		`- /* Copy the file name - everything until the next separator */`
`251`		`- Option += 8;`
	`252`	`+ /* Copy the file name */`
	`253`	`+ Option += 7; FileNameLength -= 7;`
`252`	`254`	`RtlStringCbCopyNA(FileName, sizeof(FileName),`
`253`		`- Option, strcspn(Option, " \t") * sizeof(CHAR));`
	`255`	`+ Option, FileNameLength * sizeof(CHAR));`
`254`	`256`	`}`
`255`	`257`
`256`	`258`	`/* Ramdisk image length */`
`257`		`- Option = strstr(LoadOptions, "/RDIMAGELENGTH=");`
	`259`	`+ Option = NtLdrGetOption(LoadOptions, "RDIMAGELENGTH=");`
`258`	`260`	`if (Option)`
`259`	`261`	`{`
`260`		`- RamDiskImageLength = _atoi64(Option + 15);`
	`262`	`+ RamDiskImageLength = _atoi64(Option + 14);`
`261`	`263`	`}`
`262`	`264`
`263`	`265`	`/* Ramdisk image offset */`
`264`		`- Option = strstr(LoadOptions, "/RDIMAGEOFFSET=");`
	`266`	`+ Option = NtLdrGetOption(LoadOptions, "RDIMAGEOFFSET=");`
`265`	`267`	`if (Option)`
`266`	`268`	`{`
`267`		`- RamDiskImageOffset = atol(Option + 15);`
	`269`	`+ RamDiskImageOffset = atol(Option + 14);`
`268`	`270`	`}`
`269`	`271`	`}`
`270`	`272`