#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#define ElfHeaderSize (64 * 1024)
#define ElfPages (ElfHeaderSize / 4096)
#define KERNELBASE (0xc0000000)
void get4k(FILE *file, char *buf )
{
unsigned j;
unsigned num = fread(buf, 1, 4096, file);
for ( j=num; j<4096; ++j )
buf[j] = 0;
}
void put4k(FILE *file, char *buf )
{
fwrite(buf, 1, 4096, file);
}
void death(const char *msg, FILE *fdesc, const char *fname)
{
printf(msg);
fclose(fdesc);
unlink(fname);
exit(1);
}
int main(int argc, char **argv)
{
char inbuf[4096];
FILE *ramDisk = NULL;
FILE *inputVmlinux = NULL;
FILE *outputVmlinux = NULL;
unsigned i = 0;
u_int32_t ramFileLen = 0;
u_int32_t ramLen = 0;
u_int32_t roundR = 0;
u_int32_t kernelLen = 0;
u_int32_t actualKernelLen = 0;
u_int32_t round = 0;
u_int32_t roundedKernelLen = 0;
u_int32_t ramStartOffs = 0;
u_int32_t ramPages = 0;
u_int32_t roundedKernelPages = 0;
u_int32_t hvReleaseData = 0;
u_int32_t eyeCatcher = 0xc8a5d9c4;
u_int32_t naca = 0;
u_int32_t xRamDisk = 0;
u_int32_t xRamDiskSize = 0;
if ( argc < 2 ) {
printf("Name of RAM disk file missing.\n");
exit(1);
}
if ( argc < 3 ) {
printf("Name of vmlinux file missing.\n");
exit(1);
}
if ( argc < 4 ) {
printf("Name of vmlinux output file missing.\n");
exit(1);
}
ramDisk = fopen(argv[1], "r");
if ( ! ramDisk ) {
printf("RAM disk file \"%s\" failed to open.\n", argv[1]);
exit(1);
}
inputVmlinux = fopen(argv[2], "r");
if ( ! inputVmlinux ) {
printf("vmlinux file \"%s\" failed to open.\n", argv[2]);
exit(1);
}
outputVmlinux = fopen(argv[3], "w+");
if ( ! outputVmlinux ) {
printf("output vmlinux file \"%s\" failed to open.\n", argv[3]);
exit(1);
}
fseek(ramDisk, 0, SEEK_END);
ramFileLen = ftell(ramDisk);
fseek(ramDisk, 0, SEEK_SET);
printf("%s file size = %d\n", argv[1], ramFileLen);
ramLen = ramFileLen;
roundR = 4096 - (ramLen % 4096);
if ( roundR ) {
printf("Rounding RAM disk file up to a multiple of 4096, adding %d\n", roundR);
ramLen += roundR;
}
printf("Rounded RAM disk size is %d\n", ramLen);
fseek(inputVmlinux, 0, SEEK_END);
kernelLen = ftell(inputVmlinux);
fseek(inputVmlinux, 0, SEEK_SET);
printf("kernel file size = %d\n", kernelLen);
if ( kernelLen == 0 ) {
printf("You must have a linux kernel specified as argv[2]\n");
exit(1);
}
actualKernelLen = kernelLen - ElfHeaderSize;
printf("actual kernel length (minus ELF header) = %d\n", actualKernelLen);
round = actualKernelLen % 4096;
roundedKernelLen = actualKernelLen;
if ( round )
roundedKernelLen += (4096 - round);
printf("actual kernel length rounded up to a 4k multiple = %d\n", roundedKernelLen);
ramStartOffs = roundedKernelLen;
ramPages = ramLen / 4096;
printf("RAM disk pages to copy = %d\n", ramPages);
// Copy 64K ELF header
for (i=0; i<(ElfPages); ++i) {
get4k( inputVmlinux, inbuf );
put4k( outputVmlinux, inbuf );
}
roundedKernelPages = roundedKernelLen / 4096;
fseek(inputVmlinux, ElfHeaderSize, SEEK_SET);
for ( i=0; i<roundedKernelPages; ++i ) {
get4k( inputVmlinux, inbuf );
put4k( outputVmlinux, inbuf );
}
for ( i=0; i<ramPages; ++i ) {
get4k( ramDisk, inbuf );
put4k( outputVmlinux, inbuf );
}
/* Close the input files */
fclose(ramDisk);
fclose(inputVmlinux);
/* And flush the written output file */
fflush(outputVmlinux);
/* fseek to the hvReleaseData pointer */
fseek(outputVmlinux, ElfHeaderSize + 0x24, SEEK_SET);
if (fread(&hvReleaseData, 4, 1, outputVmlinux) != 1) {
death("Could not read hvReleaseData pointer\n", outputVmlinux, argv[3]);
}
hvReleaseData = ntohl(hvReleaseData); /* Convert to native int */
printf("hvReleaseData is at %08x\n", hvReleaseData);
/* fseek to the hvReleaseData */
fseek(outputVmlinux, ElfHeaderSize + hvReleaseData, SEEK_SET);
if (fread(inbuf, 0x40, 1, outputVmlinux) != 1) {
death("Could not read hvReleaseData\n", outputVmlinux, argv[3]);
}
/* Check hvReleaseData sanity */
if (memcmp(inbuf, &eyeCatcher, 4) != 0) {
death("hvReleaseData is invalid\n", outputVmlinux, argv[3]);
}
/* Get the naca pointer */
naca = ntohl(*((u_int32_t *) &inbuf[0x0c])) - KERNELBASE;
printf("naca is at %08x\n", naca);
/* fseek to the naca */
fseek(outputVmlinux, ElfHeaderSize + naca, SEEK_SET);
if (fread(inbuf, 0x18, 1, outputVmlinux) != 1) {
death("Could not read naca\n", outputVmlinux, argv[3]);
}
xRamDisk = ntohl(*((u_int32_t *) &inbuf[0x0c]));
xRamDiskSize = ntohl(*((u_int32_t *) &inbuf[0x14]));
/* Make sure a RAM disk isn't already present */
if ((xRamDisk != 0) || (xRamDiskSize != 0)) {
death("RAM disk is already attached to this kernel\n", outputVmlinux, argv[3]);
}
/* Fill in the values */
*((u_int32_t *) &inbuf[0x0c]) = htonl(ramStartOffs);
*((u_int32_t *) &inbuf[0x14]) = htonl(ramPages);
/* Write out the new naca */
fflush(outputVmlinux);
fseek(outputVmlinux, ElfHeaderSize + naca, SEEK_SET);
if (fwrite(inbuf, 0x18, 1, outputVmlinux) != 1) {
death("Could not write naca\n", outputVmlinux, argv[3]);
}
printf("RAM Disk of 0x%x pages size is attached to the kernel at offset 0x%08x\n",
ramPages, ramStartOffs);
/* Done */
fclose(outputVmlinux);
/* Set permission to executable */
chmod(argv[3], S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
return 0;
}
