#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 (0xc000000000000000)
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)
{
fprintf(stderr, msg);
fclose(fdesc);
unlink(fname);
exit(1);
}
int main(int argc, char **argv)
{
char inbuf[4096];
FILE *ramDisk = NULL;
FILE *sysmap = NULL;
FILE *inputVmlinux = NULL;
FILE *outputVmlinux = NULL;
unsigned i = 0;
unsigned long ramFileLen = 0;
unsigned long ramLen = 0;
unsigned long roundR = 0;
unsigned long sysmapFileLen = 0;
unsigned long sysmapLen = 0;
unsigned long sysmapPages = 0;
char* ptr_end = NULL;
unsigned long offset_end = 0;
unsigned long kernelLen = 0;
unsigned long actualKernelLen = 0;
unsigned long round = 0;
unsigned long roundedKernelLen = 0;
unsigned long ramStartOffs = 0;
unsigned long ramPages = 0;
unsigned long roundedKernelPages = 0;
unsigned long hvReleaseData = 0;
u_int32_t eyeCatcher = 0xc8a5d9c4;
unsigned long naca = 0;
unsigned long xRamDisk = 0;
unsigned long xRamDiskSize = 0;
long padPages = 0;
if (argc < 2) {
fprintf(stderr, "Name of RAM disk file missing.\n");
exit(1);
}
if (argc < 3) {
fprintf(stderr, "Name of System Map input file is missing.\n");
exit(1);
}
if (argc < 4) {
fprintf(stderr, "Name of vmlinux file missing.\n");
exit(1);
}
if (argc < 5) {
fprintf(stderr, "Name of vmlinux output file missing.\n");
exit(1);
}
ramDisk = fopen(argv[1], "r");
if ( ! ramDisk ) {
fprintf(stderr, "RAM disk file \"%s\" failed to open.\n", argv[1]);
exit(1);
}
sysmap = fopen(argv[2], "r");
if ( ! sysmap ) {
fprintf(stderr, "System Map file \"%s\" failed to open.\n", argv[2]);
exit(1);
}
inputVmlinux = fopen(argv[3], "r");
if ( ! inputVmlinux ) {
fprintf(stderr, "vmlinux file \"%s\" failed to open.\n", argv[3]);
exit(1);
}
outputVmlinux = fopen(argv[4], "w+");
if ( ! outputVmlinux ) {
fprintf(stderr, "output vmlinux file \"%s\" failed to open.\n", argv[4]);
exit(1);
}
/* Input Vmlinux file */
fseek(inputVmlinux, 0, SEEK_END);
kernelLen = ftell(inputVmlinux);
fseek(inputVmlinux, 0, SEEK_SET);
printf("kernel file size = %d\n", kernelLen);
if ( kernelLen == 0 ) {
fprintf(stderr, "You must have a linux kernel specified as argv[3]\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("Vmlinux length rounded up to a 4k multiple = %ld/0x%lx \n", roundedKernelLen, roundedKernelLen);
roundedKernelPages = roundedKernelLen / 4096;
printf("Vmlinux pages to copy = %ld/0x%lx \n", roundedKernelPages, roundedKernelPages);
/* Input System Map file */
/* (needs to be processed simply to determine if we need to add pad pages due to the static variables not being included in the vmlinux) */
fseek(sysmap, 0, SEEK_END);
sysmapFileLen = ftell(sysmap);
fseek(sysmap, 0, SEEK_SET);
printf("%s file size = %ld/0x%lx \n", argv[2], sysmapFileLen, sysmapFileLen);
sysmapLen = sysmapFileLen;
roundR = 4096 - (sysmapLen % 4096);
if (roundR) {
printf("Rounding System Map file up to a multiple of 4096, adding %ld/0x%lx \n", roundR, roundR);
sysmapLen += roundR;
}
printf("Rounded System Map size is %ld/0x%lx \n", sysmapLen, sysmapLen);
/* Process the Sysmap file to determine where _end is */
sysmapPages = sysmapLen / 4096;
/* read the whole file line by line, expect that it doesn't fail */
while ( fgets(inbuf, 4096, sysmap) ) ;
/* search for _end in the last page of the system map */
ptr_end = strstr(inbuf, " _end");
if (!ptr_end) {
fprintf(stderr, "Unable to find _end in the sysmap file \n");
fprintf(stderr, "inbuf: \n");
fprintf(stderr, "%s \n", inbuf);
exit(1);
}
printf("Found _end in the last page of the sysmap - backing up 10 characters it looks like %s", ptr_end-10);
/* convert address of _end in system map to hex offset. */
offset_end = (unsigned int)strtol(ptr_end-10, NULL, 16);
/* calc how many pages we need to insert between the vmlinux and the start of the ram disk */
padPages = offset_end/4096 - roundedKernelPages;
/* Check and see if the vmlinux is already larger than _end in System.map */
if (padPages < 0) {
/* vmlinux is larger than _end - adjust the offset to the start of the embedded ram disk */
offset_end = roundedKernelLen;
printf("vmlinux is larger than _end indicates it needs to be - offset_end = %lx \n", offset_end);
padPages = 0;
printf("will insert %lx pages between the vmlinux and the start of the ram disk \n", padPages);
}
else {
/* _end is larger than vmlinux - use the offset to _end that we calculated from the system map */
printf("vmlinux is smaller than _end indicates is needed - offset_end = %lx \n", offset_end);
printf("will insert %lx pages between the vmlinux and the start of the ram disk \n", padPages);
}
/* Input Ram Disk file */
// Set the offset that the ram disk will be started at.
ramStartOffs = offset_end; /* determined from the input vmlinux file and the system map */
printf("Ram Disk will start at offset = 0x%lx \n", ramStartOffs);
fseek(ramDisk, 0, SEEK_END);
ramFileLen = ftell(ramDisk);
fseek(ramDisk, 0, SEEK_SET);
printf("%s file size = %ld/0x%lx \n", argv[1], ramFileLen, ramFileLen);
ramLen = ramFileLen;
roundR = 4096 - (ramLen % 4096);
if ( roundR ) {
printf("Rounding RAM disk file up to a multiple of 4096, adding %ld/0x%lx \n", roundR, roundR);
ramLen += roundR;
}
printf("Rounded RAM disk size is %ld/0x%lx \n", ramLen, ramLen);
ramPages = ramLen / 4096;
printf("RAM disk pages to copy = %ld/0x%lx\n", ramPages, ramPages);
// Copy 64K ELF header
for (i=0; i<(ElfPages); ++i) {
get4k( inputVmlinux, inbuf );
put4k( outputVmlinux, inbuf );
}
/* Copy the vmlinux (as full pages). */
fseek(inputVmlinux, ElfHeaderSize, SEEK_SET);
for ( i=0; i<roundedKernelPages; ++i ) {
get4k( inputVmlinux, inbuf );
put4k( outputVmlinux, inbuf );
}
/* Insert pad pages (if appropriate) that are needed between */
/* | the end of the vmlinux and the ram disk. */
for (i=0; i<padPages; ++i) {
memset(inbuf, 0, 4096);
put4k(outputVmlinux, inbuf);
}
/* Copy the ram disk (as full pages). */
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);
/* Fixup the new vmlinux to contain the ram disk starting offset (xRamDisk) and the ram disk size (xRamDiskSize) */
/* 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[4]);
}
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[4]);
}
/* Check hvReleaseData sanity */
if (memcmp(inbuf, &eyeCatcher, 4) != 0) {
death("hvReleaseData is invalid\n", outputVmlinux, argv[4]);
}
/* Get the naca pointer */
naca = ntohl(*((u_int32_t*) &inbuf[0x0C])) - KERNELBASE;
printf("Naca is at offset 0x%lx \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[4]);
}
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[4]);
}
/* 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[4]);
}
printf("Ram Disk of 0x%lx pages is attached to the kernel at offset 0x%08x\n",
ramPages, ramStartOffs);
/* Done */
fclose(outputVmlinux);
/* Set permission to executable */
chmod(argv[4], S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
return 0;
}
