From c173df46a0a12fe52fdf13323f967e9117462096 Mon Sep 17 00:00:00 2001
From: Miquel Sabaté Solà <mikisabate@gmail.com>
Date: Mon, 12 Aug 2024 08:24:44 +0200
Subject: Initial commit
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Mainly with the code I took from @popovicu's blog.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>
---
 init/Makefile        |  21 +++++++++++++++++++++
 init/file_list.txt   |   2 ++
 init/hello.c         |   8 ++++++++
 init/little_shell    | Bin 0 -> 1896643 bytes
 init/little_shell.go |  19 +++++++++++++++++++
 init/shell.c         |  32 ++++++++++++++++++++++++++++++++
 6 files changed, 82 insertions(+)
 create mode 100644 init/Makefile
 create mode 100644 init/file_list.txt
 create mode 100644 init/hello.c
 create mode 100755 init/little_shell
 create mode 100644 init/little_shell.go
 create mode 100644 init/shell.c

(limited to 'init')

diff --git a/init/Makefile b/init/Makefile
new file mode 100644
index 0000000..71405c3
--- /dev/null
+++ b/init/Makefile
@@ -0,0 +1,21 @@
+CROSS_CC 	?= riscv64-suse-linux-gcc
+CROSS_LD 	?= riscv64-suse-linux-ld
+CCFLAGS  	 = -static
+
+##
+# Targets
+
+.PHONY: hello
+hello: clean
+	$(CROSS_CC) $(CCFLAGS) -o init hello.c
+	cpio -o -H newc < file_list.txt > initramfs.cpio
+
+.PHONY: shell
+shell: clean
+	$(CROSS_CC) $(CCFLAGS) -o init shell.c
+	GOOS=linux GOARCH=riscv64 go build little_shell.go
+	cpio -o -H newc < file_list.txt > initramfs.cpio
+
+.PHONY: clean
+clean:
+	@rm -f *.o init initramfs.cpio
diff --git a/init/file_list.txt b/init/file_list.txt
new file mode 100644
index 0000000..9dd8872
--- /dev/null
+++ b/init/file_list.txt
@@ -0,0 +1,2 @@
+init
+little_shell
diff --git a/init/hello.c b/init/hello.c
new file mode 100644
index 0000000..d4e5892
--- /dev/null
+++ b/init/hello.c
@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[])
+{
+	printf("Hello, world!\n");
+	exit(0);
+}
diff --git a/init/little_shell b/init/little_shell
new file mode 100755
index 0000000..5e2446c
Binary files /dev/null and b/init/little_shell differ
diff --git a/init/little_shell.go b/init/little_shell.go
new file mode 100644
index 0000000..7324323
--- /dev/null
+++ b/init/little_shell.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Println("Hello world from Go!")
+
+	reader := bufio.NewReader(os.Stdin)
+
+	for {
+		fmt.Print("Enter your command: ")
+		line, _ := reader.ReadString('\n')
+		fmt.Printf("Your command is: %s", line)
+	}
+}
diff --git a/init/shell.c b/init/shell.c
new file mode 100644
index 0000000..d44b1c7
--- /dev/null
+++ b/init/shell.c
@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[])
+{
+	pid_t pid = fork();
+
+	if (pid == -1) {
+		printf("Unable to fork!");
+		return -1;
+	}
+
+	if (pid == 0) {
+		// This is a child process.
+		int status = execl("/little_shell", "irrelevant", NULL);
+
+		if (status == -1) {
+			printf("Forked process cannot start the little_shell");
+			return -2;
+		}
+	}
+
+	int count = 1;
+
+	while (1) {
+		printf("Hello from the original init! %d\n", count);
+		count++;
+		sleep(10);
+	}
+
+	return 0;
+}
-- 
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