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#include <stdio.h>
#include <err.h>
#include <endian.h>
#include <stdint.h>
#include <sys/types.h>
#define ANSI_FG_RED "\033[0;31m"
#define ANSI_FG_DEFAULT "\033[0;39m"
/* This program pipes it's argument file to stdout */
/* prepending it with it's size (4 bytes, little endian). */
/* It is intended to be used with our bootloader. */
int main(int argc, const char **argv) {
const char *image_file_name = "kernel.img";
if (argc > 1)
image_file_name = argv[1];
FILE *image_file_handle = fopen(image_file_name, "r");
if (!image_file_handle)
err(-1, "couldn't open" ANSI_FG_RED "%s" ANSI_FG_DEFAULT,
image_file_name);
if (fseek(image_file_handle, 0, SEEK_END))
err(-1, "error navigating through file");
ssize_t image_size = ftell(image_file_handle);
if (image_size < 0)
err(-1, "couldn't get image file size");
if (image_size >> 32)
err(-1, "file to big (should be smaller than 4G)");
if (fseek(image_file_handle, 0, SEEK_SET))
err(-1, "error navigating through file");
uint32_t image_size_le = htole32(image_size);
if (fwrite((unsigned char*) &image_size_le, 4, 1, stdout) != 1)
err(-1, "error writing number to stdout");
ssize_t bytes_left = image_size;
unsigned char buf[1024];
while (bytes_left)
{
size_t bytes_read;
if ((bytes_read = fread(buf, 1, sizeof(buf), image_file_handle))
< 1)
err(-1, "error reading the file");
if (fwrite((unsigned char*) buf, bytes_read, 1, stdout) != 1)
err(-1, "error writing to stdout");
bytes_left -= bytes_read;
}
/*
// not working - stdin breaks
while(1)
{
int bytes_read=read(0,buf,sizeof(buf));
if (fwrite((unsigned char*) buf, bytes_read, 1, stdout) != 1)
err(-1, "error writing to stdout");
}
*/
return 0;
}
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