699 lines
16 KiB
C
699 lines
16 KiB
C
/*++
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Copyright (c) 1991 Microsoft Corporation
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Module Name:
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jxenvirv.c
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Abstract:
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This module implements the HAL get and set environment variable routines
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for a MIPS system.
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Author:
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Environment:
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Kernel mode
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Revision History:
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--*/
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#include "halp.h"
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#include "arccodes.h"
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#include "jazznvr.h"
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#include "string.h"
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//
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// Define base address at which to map NVRAM.
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//
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#define NVRAM_MEMORY_BASE PTE_BASE
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//
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// Define local upcase macro.
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//
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#define UpCase(c) ((c) >= 'a' && (c) <= 'z' ? (c) - ('a' - 'A') : (c))
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KIRQL
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HalpMapNvram (
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IN PENTRYLO SavedPte
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)
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/*++
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Routine Description:
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This function is called to map the NVRAM into the address space of
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the current process.
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Arguments:
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SavedPte - Supplies a pointer to an array which receives the old NVRAM
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PTE values.
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Return Value:
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The previous IRQL is returned as the function value.
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--*/
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{
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KIRQL OldIrql;
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ENTRYLO NvramPte;
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PENTRYLO PtePointer;
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//
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// Construct a PTE to map NVRAM into the address space of the current
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// process.
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//
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NvramPte.X1 = 0;
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NvramPte.PFN = NVRAM_PHYSICAL_BASE >> PAGE_SHIFT;
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NvramPte.G = 0;
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NvramPte.V = 1;
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NvramPte.D = 1;
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#if defined(R3000)
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NvramPte.N = 1;
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#endif
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#if defined(R4000)
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NvramPte.C = UNCACHED_POLICY;
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#endif
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//
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// Raise IRQL to the highest level, flush the TB, map the NVRAM into
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// the address space of the current process, and return the previous
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// IRQL.
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//
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PtePointer = (PENTRYLO)PDE_BASE;
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KeRaiseIrql(HIGH_LEVEL, &OldIrql);
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SavedPte[0] = PtePointer[0];
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SavedPte[1] = PtePointer[1];
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KeFlushCurrentTb();
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PtePointer[0] = NvramPte;
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NvramPte.PFN += 1;
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PtePointer[1] = NvramPte;
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return OldIrql;
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}
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VOID
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HalpUnmapNvram (
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IN PENTRYLO SavedPte,
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IN KIRQL OldIrql
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)
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/*++
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Routine Description:
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This function is called to unmap the NVRAM from the address space of
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the current process.
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Arguments:
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SavedPte - Supplies a pointer to an array which contains the old NVRAM
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PTE values.
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OldIrql - Supplies the previous IRQL value.
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Return Value:
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None.
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--*/
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{
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PENTRYLO PtePointer;
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//
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// Restore the previous mapping for the current process, flush the TB,
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// and lower IRQL to its previous level.
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//
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PtePointer = (PENTRYLO)PDE_BASE;
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KeFlushCurrentTb();
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PtePointer[0] = SavedPte[0];
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PtePointer[1] = SavedPte[1];
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KeLowerIrql(OldIrql);
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return;
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}
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ARC_STATUS
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HalpEnvironmentCheckChecksum (
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VOID
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)
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/*++
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Routine Description:
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This routine checks the NVRAM environment area checksum.
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N.B. The NVRAM must be mapped before this routine is called.
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Arguments:
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None.
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Return Value:
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ESUCCESS is returned if the checksum matches. Otherwise, EIO is returned.
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--*/
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{
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ULONG Checksum1;
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ULONG Checksum2;
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PUCHAR Environment;
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ULONG Index;
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PNV_CONFIGURATION NvConfiguration;
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//
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// Compute the NVRAM environment area checksum.
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//
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NvConfiguration = (PNV_CONFIGURATION)NVRAM_MEMORY_BASE;
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Environment = &NvConfiguration->Environment[0];
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Checksum1 = 0;
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for (Index = 0; Index < LENGTH_OF_ENVIRONMENT; Index += 1) {
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Checksum1 += (ULONG)READ_REGISTER_UCHAR(&Environment[Index]);
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}
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//
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// Merge the checksum bytes from the NVRAM and compare to computed value.
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//
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Checksum2 = (ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[0]) |
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(ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[1]) << 8 |
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(ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[2]) << 16 |
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(ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[3]) << 24;
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//
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// If the checksum mismatches, then return an I/O error. Otherwise,
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// return a success status.
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//
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if (Checksum1 != Checksum2) {
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return EIO;
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} else {
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return ESUCCESS;
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}
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}
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VOID
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HalpEnvironmentSetChecksum (
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VOID
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)
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/*++
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Routine Description:
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This routine sets the NVRAM environment area checksum.
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N.B. The NVRAM must be mapped before this routine is called.
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Arguments:
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None.
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Return Value:
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None.
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--*/
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{
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ULONG Checksum;
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PUCHAR Environment;
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ULONG Index;
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PNV_CONFIGURATION NvConfiguration;
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//
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// Compute the NVRAM environment area checksum.
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//
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NvConfiguration = (PNV_CONFIGURATION)NVRAM_MEMORY_BASE;
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Environment = &NvConfiguration->Environment[0];
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Checksum = 0;
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for (Index = 0; Index < LENGTH_OF_ENVIRONMENT; Index += 1) {
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Checksum += (ULONG)READ_REGISTER_UCHAR(&Environment[Index]);
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}
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//
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// Write the NVRAM environment area checksum.
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//
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WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[0],
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(UCHAR)(Checksum & 0xFF));
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WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[1],
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(UCHAR)((Checksum >> 8) & 0xFF));
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WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[2],
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(UCHAR)((Checksum >> 16) & 0xFF));
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WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[3],
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(UCHAR)(Checksum >> 24));
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return;
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}
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ARC_STATUS
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HalpFindEnvironmentVariable (
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IN PCHAR Variable,
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OUT PULONG VariableIndex,
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OUT PULONG ValueIndex
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)
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/*++
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Routine Description:
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This routine performs a case insensitive search of the NVRAM environment
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area for the specified variable name.
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N.B. The NVRAM must be mapped before this routine is called.
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Arguments:
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Variable - Supplies a pointer to a zero terminated string containing an
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environment variable name.
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Return Value:
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ESUCCESS is returned if the specified variable name is located. Otherwise,
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ENOENT is returned.
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--*/
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{
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PUCHAR Environment;
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ULONG Index;
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PUCHAR Name;
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//
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// If the variable name is null, then return no entry found.
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//
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if (*Variable == 0) {
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return ENOENT;
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}
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//
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// Search the environment section of the NVRAM for a variable name match.
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//
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Environment = &((PNV_CONFIGURATION)NVRAM_MEMORY_BASE)->Environment[0];
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Index = 0;
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do {
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//
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// Set name to the beginning of the variable name and record the
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// current index value.
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//
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Name = Variable;
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*VariableIndex = Index;
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//
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// Search until the end of the current environment variable, the
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// end of the specified variable name, or the end of the NVRAM is
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// reached.
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//
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while ((Index < LENGTH_OF_ENVIRONMENT) &&
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(READ_REGISTER_UCHAR(&Environment[Index]) != 0) && (*Name != 0)) {
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if (READ_REGISTER_UCHAR(&Environment[Index]) != UpCase(*Name)) {
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break;
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}
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Name += 1;
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Index += 1;
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}
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//
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// Check for a match which is signified by the end of the variable
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// name and the equal separator in the current environment variable.
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//
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if ((*Name == 0) && (READ_REGISTER_UCHAR(&Environment[Index]) == '=')) {
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*ValueIndex = Index + 1;
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return ESUCCESS;
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}
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//
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// Advance to the start of the next variable.
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//
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while ((Index < LENGTH_OF_ENVIRONMENT) &&
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(READ_REGISTER_UCHAR(&Environment[Index]) != 0)) {
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Index += 1;
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}
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Index += 1;
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} while (Index < LENGTH_OF_ENVIRONMENT);
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return ENOENT;
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}
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ARC_STATUS
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HalGetEnvironmentVariable (
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IN PCHAR Variable,
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IN USHORT Length,
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OUT PCHAR Buffer
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)
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/*++
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Routine Description:
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This function locates an environment variable and returns its value.
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Arguments:
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Variable - Supplies a pointer to a zero terminated environment variable
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name.
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Length - Supplies the length of the value buffer in bytes.
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Buffer - Supplies a pointer to a buffer that receives the variable value.
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Return Value:
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ESUCCESS is returned if the enviroment variable is located. Otherwise,
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ENOENT is returned.
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--*/
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{
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PUCHAR Environment;
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ULONG Index;
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KIRQL OldIrql;
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ENTRYLO SavedPte[2];
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ARC_STATUS Status;
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ULONG ValueIndex;
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ULONG VariableIndex;
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//
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// Map the NVRAM into the address space of the current process.
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//
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OldIrql = HalpMapNvram(&SavedPte[0]);
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//
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// If the checksum does not match or the specified variable cannot
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// be located, then set the status to no entry found. Otherwise, copy
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// the respective variable value to the specified output buffer.
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//
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Environment = &((PNV_CONFIGURATION)NVRAM_MEMORY_BASE)->Environment[0];
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if ((HalpEnvironmentCheckChecksum() != ESUCCESS) ||
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(HalpFindEnvironmentVariable(Variable,
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&VariableIndex,
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&ValueIndex) != ESUCCESS)) {
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Status = ENOENT;
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} else {
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//
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// Copy the specified value to the output buffer.
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//
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for (Index = 0; Index < Length; Index += 1) {
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*Buffer = READ_REGISTER_UCHAR(&Environment[ValueIndex]);
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if (*Buffer == 0) {
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break;
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}
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Buffer += 1;
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ValueIndex += 1;
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}
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//
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// If the length terminated the loop, then return not enough memory.
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// Otherwise, return success.
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//
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if (Index == Length) {
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Status = ENOMEM;
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} else {
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Status = ESUCCESS;
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}
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}
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//
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// Unmap the NVRAM from the address space of the current process and
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// return the function status.
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//
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HalpUnmapNvram(&SavedPte[0], OldIrql);
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return Status;
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}
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ARC_STATUS
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HalSetEnvironmentVariable (
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IN PCHAR Variable,
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IN PCHAR Value
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)
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/*++
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Routine Description:
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This function creates an environment variable with the specified value.
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Arguments:
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Variable - Supplies a pointer to an environment variable name.
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Value - Supplies a pointer to the environment variable value.
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Return Value:
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ESUCCESS is returned if the environment variable is created. Otherwise,
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ENOMEM is returned.
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--*/
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{
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UCHAR Character;
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PUCHAR Environment;
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KIRQL OldIrql;
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ENTRYLO SavedPte[2];
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ARC_STATUS Status;
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ULONG TopIndex;
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ULONG VariableIndex;
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ULONG VariableLength;
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ULONG ValueEnd;
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ULONG ValueIndex;
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ULONG ValueLength;
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//
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// Map the NVRAM into the address space of the current process.
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//
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OldIrql = HalpMapNvram(&SavedPte[0]);
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Environment = &((PNV_CONFIGURATION)NVRAM_MEMORY_BASE)->Environment[0];
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//
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// If the checksum does not match, then set status to an I/O error.
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//
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if (HalpEnvironmentCheckChecksum() != ESUCCESS) {
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Status = EIO;
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goto Unmap;
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}
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//
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// Determine the top of the environment area by scanning backwards until
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// the a non-null character is found or the beginning of the environment
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// area is reached.
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//
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for (TopIndex = (LENGTH_OF_ENVIRONMENT - 1); TopIndex > 0; TopIndex -= 1) {
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if (READ_REGISTER_UCHAR(&Environment[TopIndex]) != '\0') {
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break;
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}
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}
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//
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// If the environment area contains any data, then adjust the top index
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// to the first free byte.
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//
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if (TopIndex != 0) {
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TopIndex += 2;
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}
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//
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// Compute the length of the variable name and the variable value.
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//
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VariableLength = strlen(Variable) + 1;
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ValueLength = strlen(Value) + 1;
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//
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// Check to determine if the specified variable is currently defined.
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//
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if (HalpFindEnvironmentVariable(Variable,
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&VariableIndex,
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&ValueIndex) == ESUCCESS) {
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//
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// The specified variable is currently defined. Determine the end
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// of the variable value by scanning forward to the zero termination
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// byte.
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//
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ValueEnd = ValueIndex;
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while (READ_REGISTER_UCHAR(&Environment[ValueEnd]) != '\0') {
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ValueEnd += 1;
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}
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ValueEnd += 1;
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//
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// If there is enough free space for the new variable value, then
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// remove the current variable name and value from the environment
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// area, insert the new variable value at the end of the environment
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// if it is not null, and set the status to success. Otherwise, set
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// the status to no space available.
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//
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if ((ValueEnd - ValueIndex + LENGTH_OF_ENVIRONMENT - TopIndex) >= ValueLength) {
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while (ValueEnd != TopIndex) {
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Character = READ_REGISTER_UCHAR(&Environment[ValueEnd]);
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WRITE_REGISTER_UCHAR(&Environment[VariableIndex], Character);
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ValueEnd += 1;
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VariableIndex += 1;
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}
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ValueIndex = VariableIndex;
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while (ValueIndex != TopIndex) {
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WRITE_REGISTER_UCHAR(&Environment[ValueIndex], '\0');
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ValueIndex += 1;
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}
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//
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// If the new variable value is not null, then copy the variable
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// name and the variable value into the enviroment area.
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//
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if (*Value != '\0') {
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//
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// copy the variable name to the environment area.
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//
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do {
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WRITE_REGISTER_UCHAR(&Environment[VariableIndex], UpCase(*Variable));
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VariableIndex += 1;
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Variable += 1;
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} while (*Variable != '\0');
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//
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// Insert separator character and copy variable value to the
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// environment area.
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//
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WRITE_REGISTER_UCHAR(&Environment[VariableIndex], '=');
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VariableIndex += 1;
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do {
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WRITE_REGISTER_UCHAR(&Environment[VariableIndex], *Value);
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VariableIndex += 1;
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Value += 1;
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} while (*Value != '\0');
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}
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Status = ESUCCESS;
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} else {
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Status = ENOSPC;
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}
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} else {
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//
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// The specified variable does not currently have a value. If the
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// specified variable is null or has no value, then set the status
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// to success. Otherwise, if the free area is not large enough to
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// hold the new variable name and its value, then set the status to
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// no space available. Otherwise, insert the variable name and value
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// at the end of the environment area and set the status to success.
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//
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|
||
if ((*Variable == '\0') || (*Value == '\0')) {
|
||
Status = ESUCCESS;
|
||
|
||
} else if ((LENGTH_OF_ENVIRONMENT - TopIndex) <
|
||
(VariableLength + ValueLength)) {
|
||
Status = ENOSPC;
|
||
|
||
} else {
|
||
|
||
//
|
||
// copy the variable name to the environment area.
|
||
//
|
||
|
||
do {
|
||
WRITE_REGISTER_UCHAR(&Environment[TopIndex], UpCase(*Variable));
|
||
TopIndex += 1;
|
||
Variable += 1;
|
||
} while (*Variable != '\0');
|
||
|
||
//
|
||
// Insert separator character and copy variable value to the
|
||
// environment area.
|
||
//
|
||
|
||
WRITE_REGISTER_UCHAR(&Environment[TopIndex], '=');
|
||
TopIndex += 1;
|
||
do {
|
||
WRITE_REGISTER_UCHAR(&Environment[TopIndex], *Value);
|
||
TopIndex += 1;
|
||
Value += 1;
|
||
} while (*Value != '\0');
|
||
|
||
Status = ESUCCESS;
|
||
}
|
||
}
|
||
|
||
//
|
||
// Compute the new checksum and write to the environment area.
|
||
//
|
||
|
||
HalpEnvironmentSetChecksum();
|
||
|
||
//
|
||
// Unmap the NVRAM from the address space of the current process.
|
||
//
|
||
|
||
Unmap:
|
||
HalpUnmapNvram(&SavedPte[0], OldIrql);
|
||
return Status;
|
||
}
|