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NT4/private/ntos/nthals/halacr/mips/jxenvirv.c

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First commit
2001-01-01 00:00:00 +01:00
/*++
Copyright (c) 1991 Microsoft Corporation
Module Name:
jxenvirv.c
Abstract:
This module implements the HAL get and set environment variable routines
for a MIPS system.
Author:
Environment:
Kernel mode
Revision History:
--*/
#include "halp.h"
#include "arccodes.h"
#include "jazznvr.h"
#include "string.h"
//
// Define base address at which to map NVRAM.
//
#define NVRAM_MEMORY_BASE PTE_BASE
//
// Define local upcase macro.
//
#define UpCase(c) ((c) >= 'a' && (c) <= 'z' ? (c) - ('a' - 'A') : (c))
KIRQL
HalpMapNvram (
IN PENTRYLO SavedPte
)
/*++
Routine Description:
This function is called to map the NVRAM into the address space of
the current process.
Arguments:
SavedPte - Supplies a pointer to an array which receives the old NVRAM
PTE values.
Return Value:
The previous IRQL is returned as the function value.
--*/
{
KIRQL OldIrql;
ENTRYLO NvramPte;
PENTRYLO PtePointer;
//
// Construct a PTE to map NVRAM into the address space of the current
// process.
//
NvramPte.X1 = 0;
NvramPte.PFN = NVRAM_PHYSICAL_BASE >> PAGE_SHIFT;
NvramPte.G = 0;
NvramPte.V = 1;
NvramPte.D = 1;
#if defined(R3000)
NvramPte.N = 1;
#endif
#if defined(R4000)
NvramPte.C = UNCACHED_POLICY;
#endif
//
// Raise IRQL to the highest level, flush the TB, map the NVRAM into
// the address space of the current process, and return the previous
// IRQL.
//
PtePointer = (PENTRYLO)PDE_BASE;
KeRaiseIrql(HIGH_LEVEL, &OldIrql);
SavedPte[0] = PtePointer[0];
SavedPte[1] = PtePointer[1];
KeFlushCurrentTb();
PtePointer[0] = NvramPte;
NvramPte.PFN += 1;
PtePointer[1] = NvramPte;
return OldIrql;
}
VOID
HalpUnmapNvram (
IN PENTRYLO SavedPte,
IN KIRQL OldIrql
)
/*++
Routine Description:
This function is called to unmap the NVRAM from the address space of
the current process.
Arguments:
SavedPte - Supplies a pointer to an array which contains the old NVRAM
PTE values.
OldIrql - Supplies the previous IRQL value.
Return Value:
None.
--*/
{
PENTRYLO PtePointer;
//
// Restore the previous mapping for the current process, flush the TB,
// and lower IRQL to its previous level.
//
PtePointer = (PENTRYLO)PDE_BASE;
KeFlushCurrentTb();
PtePointer[0] = SavedPte[0];
PtePointer[1] = SavedPte[1];
KeLowerIrql(OldIrql);
return;
}
ARC_STATUS
HalpEnvironmentCheckChecksum (
VOID
)
/*++
Routine Description:
This routine checks the NVRAM environment area checksum.
N.B. The NVRAM must be mapped before this routine is called.
Arguments:
None.
Return Value:
ESUCCESS is returned if the checksum matches. Otherwise, EIO is returned.
--*/
{
ULONG Checksum1;
ULONG Checksum2;
PUCHAR Environment;
ULONG Index;
PNV_CONFIGURATION NvConfiguration;
//
// Compute the NVRAM environment area checksum.
//
NvConfiguration = (PNV_CONFIGURATION)NVRAM_MEMORY_BASE;
Environment = &NvConfiguration->Environment[0];
Checksum1 = 0;
for (Index = 0; Index < LENGTH_OF_ENVIRONMENT; Index += 1) {
Checksum1 += (ULONG)READ_REGISTER_UCHAR(&Environment[Index]);
}
//
// Merge the checksum bytes from the NVRAM and compare to computed value.
//
Checksum2 = (ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[0]) |
(ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[1]) << 8 |
(ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[2]) << 16 |
(ULONG)READ_REGISTER_UCHAR(&NvConfiguration->Checksum2[3]) << 24;
//
// If the checksum mismatches, then return an I/O error. Otherwise,
// return a success status.
//
if (Checksum1 != Checksum2) {
return EIO;
} else {
return ESUCCESS;
}
}
VOID
HalpEnvironmentSetChecksum (
VOID
)
/*++
Routine Description:
This routine sets the NVRAM environment area checksum.
N.B. The NVRAM must be mapped before this routine is called.
Arguments:
None.
Return Value:
None.
--*/
{
ULONG Checksum;
PUCHAR Environment;
ULONG Index;
PNV_CONFIGURATION NvConfiguration;
//
// Compute the NVRAM environment area checksum.
//
NvConfiguration = (PNV_CONFIGURATION)NVRAM_MEMORY_BASE;
Environment = &NvConfiguration->Environment[0];
Checksum = 0;
for (Index = 0; Index < LENGTH_OF_ENVIRONMENT; Index += 1) {
Checksum += (ULONG)READ_REGISTER_UCHAR(&Environment[Index]);
}
//
// Write the NVRAM environment area checksum.
//
WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[0],
(UCHAR)(Checksum & 0xFF));
WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[1],
(UCHAR)((Checksum >> 8) & 0xFF));
WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[2],
(UCHAR)((Checksum >> 16) & 0xFF));
WRITE_REGISTER_UCHAR(&NvConfiguration->Checksum2[3],
(UCHAR)(Checksum >> 24));
return;
}
ARC_STATUS
HalpFindEnvironmentVariable (
IN PCHAR Variable,
OUT PULONG VariableIndex,
OUT PULONG ValueIndex
)
/*++
Routine Description:
This routine performs a case insensitive search of the NVRAM environment
area for the specified variable name.
N.B. The NVRAM must be mapped before this routine is called.
Arguments:
Variable - Supplies a pointer to a zero terminated string containing an
environment variable name.
Return Value:
ESUCCESS is returned if the specified variable name is located. Otherwise,
ENOENT is returned.
--*/
{
PUCHAR Environment;
ULONG Index;
PUCHAR Name;
//
// If the variable name is null, then return no entry found.
//
if (*Variable == 0) {
return ENOENT;
}
//
// Search the environment section of the NVRAM for a variable name match.
//
Environment = &((PNV_CONFIGURATION)NVRAM_MEMORY_BASE)->Environment[0];
Index = 0;
do {
//
// Set name to the beginning of the variable name and record the
// current index value.
//
Name = Variable;
*VariableIndex = Index;
//
// Search until the end of the current environment variable, the
// end of the specified variable name, or the end of the NVRAM is
// reached.
//
while ((Index < LENGTH_OF_ENVIRONMENT) &&
(READ_REGISTER_UCHAR(&Environment[Index]) != 0) && (*Name != 0)) {
if (READ_REGISTER_UCHAR(&Environment[Index]) != UpCase(*Name)) {
break;
}
Name += 1;
Index += 1;
}
//
// Check for a match which is signified by the end of the variable
// name and the equal separator in the current environment variable.
//
if ((*Name == 0) && (READ_REGISTER_UCHAR(&Environment[Index]) == '=')) {
*ValueIndex = Index + 1;
return ESUCCESS;
}
//
// Advance to the start of the next variable.
//
while ((Index < LENGTH_OF_ENVIRONMENT) &&
(READ_REGISTER_UCHAR(&Environment[Index]) != 0)) {
Index += 1;
}
Index += 1;
} while (Index < LENGTH_OF_ENVIRONMENT);
return ENOENT;
}
ARC_STATUS
HalGetEnvironmentVariable (
IN PCHAR Variable,
IN USHORT Length,
OUT PCHAR Buffer
)
/*++
Routine Description:
This function locates an environment variable and returns its value.
Arguments:
Variable - Supplies a pointer to a zero terminated environment variable
name.
Length - Supplies the length of the value buffer in bytes.
Buffer - Supplies a pointer to a buffer that receives the variable value.
Return Value:
ESUCCESS is returned if the enviroment variable is located. Otherwise,
ENOENT is returned.
--*/
{
PUCHAR Environment;
ULONG Index;
KIRQL OldIrql;
ENTRYLO SavedPte[2];
ARC_STATUS Status;
ULONG ValueIndex;
ULONG VariableIndex;
//
// Map the NVRAM into the address space of the current process.
//
OldIrql = HalpMapNvram(&SavedPte[0]);
//
// If the checksum does not match or the specified variable cannot
// be located, then set the status to no entry found. Otherwise, copy
// the respective variable value to the specified output buffer.
//
Environment = &((PNV_CONFIGURATION)NVRAM_MEMORY_BASE)->Environment[0];
if ((HalpEnvironmentCheckChecksum() != ESUCCESS) ||
(HalpFindEnvironmentVariable(Variable,
&VariableIndex,
&ValueIndex) != ESUCCESS)) {
Status = ENOENT;
} else {
//
// Copy the specified value to the output buffer.
//
for (Index = 0; Index < Length; Index += 1) {
*Buffer = READ_REGISTER_UCHAR(&Environment[ValueIndex]);
if (*Buffer == 0) {
break;
}
Buffer += 1;
ValueIndex += 1;
}
//
// If the length terminated the loop, then return not enough memory.
// Otherwise, return success.
//
if (Index == Length) {
Status = ENOMEM;
} else {
Status = ESUCCESS;
}
}
//
// Unmap the NVRAM from the address space of the current process and
// return the function status.
//
HalpUnmapNvram(&SavedPte[0], OldIrql);
return Status;
}
ARC_STATUS
HalSetEnvironmentVariable (
IN PCHAR Variable,
IN PCHAR Value
)
/*++
Routine Description:
This function creates an environment variable with the specified value.
Arguments:
Variable - Supplies a pointer to an environment variable name.
Value - Supplies a pointer to the environment variable value.
Return Value:
ESUCCESS is returned if the environment variable is created. Otherwise,
ENOMEM is returned.
--*/
{
UCHAR Character;
PUCHAR Environment;
KIRQL OldIrql;
ENTRYLO SavedPte[2];
ARC_STATUS Status;
ULONG TopIndex;
ULONG VariableIndex;
ULONG VariableLength;
ULONG ValueEnd;
ULONG ValueIndex;
ULONG ValueLength;
//
// Map the NVRAM into the address space of the current process.
//
OldIrql = HalpMapNvram(&SavedPte[0]);
Environment = &((PNV_CONFIGURATION)NVRAM_MEMORY_BASE)->Environment[0];
//
// If the checksum does not match, then set status to an I/O error.
//
if (HalpEnvironmentCheckChecksum() != ESUCCESS) {
Status = EIO;
goto Unmap;
}
//
// Determine the top of the environment area by scanning backwards until
// the a non-null character is found or the beginning of the environment
// area is reached.
//
for (TopIndex = (LENGTH_OF_ENVIRONMENT - 1); TopIndex > 0; TopIndex -= 1) {
if (READ_REGISTER_UCHAR(&Environment[TopIndex]) != '\0') {
break;
}
}
//
// If the environment area contains any data, then adjust the top index
// to the first free byte.
//
if (TopIndex != 0) {
TopIndex += 2;
}
//
// Compute the length of the variable name and the variable value.
//
VariableLength = strlen(Variable) + 1;
ValueLength = strlen(Value) + 1;
//
// Check to determine if the specified variable is currently defined.
//
if (HalpFindEnvironmentVariable(Variable,
&VariableIndex,
&ValueIndex) == ESUCCESS) {
//
// The specified variable is currently defined. Determine the end
// of the variable value by scanning forward to the zero termination
// byte.
//
ValueEnd = ValueIndex;
while (READ_REGISTER_UCHAR(&Environment[ValueEnd]) != '\0') {
ValueEnd += 1;
}
ValueEnd += 1;
//
// If there is enough free space for the new variable value, then
// remove the current variable name and value from the environment
// area, insert the new variable value at the end of the environment
// if it is not null, and set the status to success. Otherwise, set
// the status to no space available.
//
if ((ValueEnd - ValueIndex + LENGTH_OF_ENVIRONMENT - TopIndex) >= ValueLength) {
while (ValueEnd != TopIndex) {
Character = READ_REGISTER_UCHAR(&Environment[ValueEnd]);
WRITE_REGISTER_UCHAR(&Environment[VariableIndex], Character);
ValueEnd += 1;
VariableIndex += 1;
}
ValueIndex = VariableIndex;
while (ValueIndex != TopIndex) {
WRITE_REGISTER_UCHAR(&Environment[ValueIndex], '\0');
ValueIndex += 1;
}
//
// If the new variable value is not null, then copy the variable
// name and the variable value into the enviroment area.
//
if (*Value != '\0') {
//
// copy the variable name to the environment area.
//
do {
WRITE_REGISTER_UCHAR(&Environment[VariableIndex], UpCase(*Variable));
VariableIndex += 1;
Variable += 1;
} while (*Variable != '\0');
//
// Insert separator character and copy variable value to the
// environment area.
//
WRITE_REGISTER_UCHAR(&Environment[VariableIndex], '=');
VariableIndex += 1;
do {
WRITE_REGISTER_UCHAR(&Environment[VariableIndex], *Value);
VariableIndex += 1;
Value += 1;
} while (*Value != '\0');
}
Status = ESUCCESS;
} else {
Status = ENOSPC;
}
} else {
//
// The specified variable does not currently have a value. If the
// specified variable is null or has no value, then set the status
// to success. Otherwise, if the free area is not large enough to
// hold the new variable name and its value, then set the status to
// no space available. Otherwise, insert the variable name and value
// at the end of the environment area and set the status to success.
//
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;
}
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