diff options
| -rw-r--r-- | Makefile | 5 | ||||
| -rw-r--r-- | pipe_image.c | 55 |
2 files changed, 59 insertions, 1 deletions
@@ -47,7 +47,10 @@ qemu-bin : kernel7.img qemu-loader : loader.img qemu-system-arm -m 256 -M raspi2 -serial stdio -kernel $^ +pipe_image : pipe_image.c + gcc -Wall -std=gnu99 -O3 $^ -o $@ + clean : - -rm *.img *.elf *.o + -rm *.img *.elf *.o pipe_image .PHONY: all qemu-elf qemu-bin clean diff --git a/pipe_image.c b/pipe_image.c new file mode 100644 index 0000000..7e24ea7 --- /dev/null +++ b/pipe_image.c @@ -0,0 +1,55 @@ +#include <stdio.h> +#include <err.h> +#include <endian.h> +#include <stdint.h> +#include <sys/types.h> + +#define ANSI_FG_RED "\033[0;31m" + +/* 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 (i.e. by piping kernel image to UART). */ + +int main(int argc, char **argv) { + char *image_file_name = argc > 1 ? argv[1] : "kernel7.img"; + + FILE *image_file_handle = fopen(image_file_name, "r"); + + if (!image_file_handle) + err(-1, "couldn't open" ANSI_FG_RED "%s", 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(&image_size_le, 4, 1, stdout) != 1) + err(-1, "couldn't write to stdout"); + + ssize_t bytes_left = image_size; + + 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(buf, bytes_read, 1, stdout) != 1) + err(-1, "error writing to stdout"); + + bytes_left -= bytes_read; + } +} |