From a047e3ecf53f9995afe0422bce11f359a019e8be Mon Sep 17 00:00:00 2001 From: Art Yerkes Date: Sat, 10 Jan 2004 21:04:49 +0000 Subject: [PATCH] Added usage document. svn path=/trunk/; revision=7555 --- .../lib/kjs/Kernel_Javascript_Support.html | 112 ++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 reactos/lib/kjs/Kernel_Javascript_Support.html diff --git a/reactos/lib/kjs/Kernel_Javascript_Support.html b/reactos/lib/kjs/Kernel_Javascript_Support.html new file mode 100644 index 00000000000..ee287affee5 --- /dev/null +++ b/reactos/lib/kjs/Kernel_Javascript_Support.html @@ -0,0 +1,112 @@ + + + + + Kernel Javascript Support + + +

Kernel Javascript support

+
+This document details the kernel javascript debugging extension +recently added to the reactos kernel.
+

Enabling

+The extension is enabled when KDBG := 1 is set in config in the reactos source +tree.
+
+kdb presents the usual prompt when ReactOS starts, but the 'js' command initializes the +javascript system and allows the user to start working with the system +in javascript.  A welcome banner is displayed when the system is +ready, along with the prompt kjs:>.
+

Using

+You may type as many lines in each input as needed.  To cancel +some input, just enter '.' as the only character on an input +line.  To exit from the javascript interpreter, enter '.' on the +first input line.  In order to determine when the user is finished +typing, the kernel javascript system uses the harmless ';;' +sequence.  Entering ';;' anywhere in the input terminates input +and evaluates the current input buffer.  The buffer is emptied +afterward.  Any javascript error messages or output are printed +before the next prompt is displayed.  Note that the interpreter +does not automatically print the evaluation results, so it's useful to +wrap simple evaluations with write().
+
+

Sample Session

+
kdb:> js
JS Registry Init Complete.  Welcome to ReactOS kernel scripting
Kernel Debugger Script Interface (JavaScript :-)
Terminate input with ;; and end scripting with .
kjs:> write(System.getmodule(1));;                                              
hal.dll,3225501696                                                              
kjs:> write(System.getmodule(1)[1].toString(16));;                 
c0414000
kjs:> write(ebp().toString(16));;
cee8bf84

kjs:> function dump_sec(base) {
.....   base2 = peekw(base + 0x3c) + base;
.....   sec_off = 0xf8;
.....   for( i = 0; peekl(base2 + sec_off + (40 * i)); i++ ) {
.....     base_sec = base2 + sec_off + (40 * i);
.....     write("Section: " + System.mread(0,base_sec) + "\n");
.....     write("RVA:     " + peekl(base_sec + 12).toString(16) + "\n");
.....   }
..... }
..... ;;
kjs:> dump_sec(0xc0000000);;
Section: .text
RVA:     1000
Section: init
RVA:     e6000
Section: .data
RVA:     f4000
Section: .edata
RVA:     10d000
Section: .idata
RVA:     115000
Section: .rsrc
RVA:     116000
Section: .bss
RVA:     118000
Section: .reloc
RVA:     15a000

kjs:> var key = "\\registry\\machine\\system\\currentcontrolset\\services\\ne20001\\parameters\\tcpip";;
kjs:> write(regread(key,"defaultgateway"));;
10.0.0.1
+

Builtin and initialized functions

+These functions are available after a successful javascript +initialization:
+
+System.getmodule(n) => (string,int) +array
+
+Returns the name and base address of the nth module in the kernel +module list.
+
+System.mread(s,address) => +integer/string
+
+System.mread reads a value from memory and returns it.  s +determines what type of read is performed, and address specifies the +starting address of the operation.
+
+Valid values of s are:
+
+0 -- Read a null-terminated ascii string
+1 -- Read a byte
+2 -- Read a word
+4 -- Read a dword
+
+System.mwrite(s,address,value) => +bool
+
+System.mwrite writes a value to a memory address.  The operand +size depends on s, 1 for byte, 2 for word, 4 for dword.
+
+System.print(...) => undefined
+
+Uses DbgPrint to print the specified output.  In javascript, every +value is printable, so feel free to give any value type to print.
+Use C style escapes for tabs and newlines: \t and \n.
+
+System.regs(int) => int
+
+System.regs read the specified word value from the TRAP_FRAME given to +kdb when it was started.  This is useful for locating the stack, +along with various other queries.  The machine registers are also +provided as named functions by javascript, for example ebp() and eax().
+
+System.regread(key,value) => +string/undefined
+
+System.regread reads a string value from the registry (as a member of +the specified registry key).  If the read is successful, the +string value contained in it is returned.  If the value cannot be +read, then undefined is returned.
+
+This method is used by the registry initializer to read the +initialization strings.
+
+ebp(), eip(), esp() ... vm86_gs() +=> int
+
+Every register provided by the system trap frame is available as a +global function of the same name.  This makes reading specific +registers easy.
+
+peek,peekw,peekl(int addr) => int
+
+Aliases for System.mread([1,2,4],addr)
+
+poke,pokew,pokel(int addr, int value) +=> int
+
+Aliases for System.mwrite([1,2,4],addr,value)
+
+write(...) => undefined
+
+Alias for System.print
+ +