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Including file data in binary
Posted: Tue Oct 26, 2004 4:10 pm
by Gnome
Hey everyone,
I'm looking for a way to include the contents of a (binary) file in a compiled binary, such that a pointer to the data (and the length), is exported through a symbol. I faintly remember reading about some way of doing this, but I forget how. I figure it likely boils down to some trick with ld to make it include verbatim some file. One (ugly) way I see is to write a script to read the file and encode it as a C array, then compile and that in.
Specifically, I'm looking to include TTF font data in my kernel image to be used in the early stages of the boot process for writing status information to the VESA framebuffer, before the filesystem is loaded and I can get it off the disk.
Thanks in advance.
Re:Including file data in binary
Posted: Wed Oct 27, 2004 2:55 am
by df
here is my bin2c code.
it creates a .h file you include in your C.
it defines a {name}_size and {name}_data of the object.
Code: Select all
// bin2c v0.2 - stuart george
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
unsigned long fsize;
int lcount;
unsigned char c;
FILE *fp;
if(argc<3)
{
printf("bin2c inputfile recordname\n");
exit(0);
}
fp = fopen(argv[1], "rb");
if(fp!=NULL)
{
fseek(fp, 0x0L, SEEK_END);
fsize = ftell(fp);
fseek(fp, 0x0L, SEEK_SET);
lcount = 0;
printf("unsigned long %s_size = %li\n", argv[2], fsize);
printf("unsigned char %s_data[]=\n{\n\t", argv[2]);
while(ftell(fp) < fsize)
{
c = fgetc(fp);
if(lcount > 0)
printf(", ");
printf("0x%02X", c);
lcount++;
if(lcount == 10)
{
lcount = 0;
printf("\n\t");
}
}
fclose(fp);
printf("\n};\n");
}
else
{
fprintf(stderr, "Could not open file\n");
}
return 0;
}
Re:Including file data in binary
Posted: Wed Oct 27, 2004 9:19 am
by Curufir
The real easy way would be to just include it in an asm file and link that into your C file.
Eg NASM
Code: Select all
global start_ttf, end_ttf
start_ttf:
incbin "path_to_font"
end_ttf:
Assemble to a nice object format, then use those symbols in your C file.
Re:Including file data in binary
Posted: Thu Oct 28, 2004 9:40 am
by Candy
Curufir wrote:
The real easy way would be to just include it in an asm file and link that into your C file.
Eg NASM
Code: Select all
global start_ttf, end_ttf
start_ttf:
incbin "path_to_font"
end_ttf:
Assemble to a nice object format, then use those symbols in your C file.
I think you could make that more slick by making a program called something like make_bin.sh that "compiles" the binary to an includable binary object. It'd make the nasm file above and then self-feed it through nasm, then delete the temp file and keep the output file.
Re:Including file data in binary
Posted: Thu Oct 28, 2004 11:28 am
by Curufir
For your pleasure and amusement here's a script that'll let you get an object file with a start/end symbol for any binary input:
Code: Select all
#!/bin/bash
# This script may be considered placed within the public domain
TEMP_FILE="/var/tmp/bin2obj$RANDOM.asm"
if [ "$#" -ne 4 ]
then
echo "usage: $0 <input> <output> <start symbol> <end symbol>"
exit 1
elif [ -f $1 ]
then
cat <<-Finish > $TEMP_FILE
global $3, $4
$3:
incbin "$1"
$4:
Finish
nasm -f elf -o $2 $TEMP_FILE
rm $TEMP_FILE
exit 0
else
echo "Input file does not exist"
exit 1
fi
Sample Usage:
bin2obj.sh /path/to/my_ttf_font /path/to/ttf.o start_symbol end_symbol
Re:Including file data in binary
Posted: Fri Oct 29, 2004 11:14 am
by Gnome
Wow, thanks guys. I think that'll work wonders.
