Task4

module3/Makefile

@@ -0,0 +1,9 @@
+obj-m += proc_mmaneg.o
+
+ABS_PATH_TO_VROOT ?= ../initramfs
+PATH_TO_MODULE_BUILD=$(ABS_PATH_TO_VROOT)/lib/modules/6.7.4/build
+
+all:
+	make -C "$(PATH_TO_MODULE_BUILD)" M="$(PWD)" modules
+clean:
+	make -C "$(PATH_TO_MODULE_BUILD)" M="$(PWD)" clean

module3/compile.sh

@@ -0,0 +1,11 @@
+cp -r ../module3 ../../ || exit
+cd ../../module3 || exit
+make clean || exit
+make all || exit
+cp proc_mmaneg.ko ../initramfs/lib/modules/6.7.4/ || exit
+cd ../initramfs || exit
+find . | cpio -ov --format=newc | gzip -9 > ../try/initramfs.gz || exit
+cd ..
+# cleanup
+rm -r module3
+rm initramfs/lib/modules/6.7.4/proc_mmaneg.ko

module3/proc_mmaneg.c

@@ -0,0 +1,153 @@
+//
+// Created by mikhail on 21.05.24.
+//
+
+// Module registration
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+// Creation of character device
+#include <linux/cdev.h>
+#include <linux/fs.h>
+
+// Procfs
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/mm.h>
+#include <linux/uaccess.h>
+#include <linux/mm_types.h>
+#include <asm/page.h>
+#include <asm/io.h>
+
+//------------------------------------------------------------------------------
+
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Me");
+MODULE_DESCRIPTION("Proc mmaneg module");
+
+// Variables
+
+#define PROCFS_MAX_SIZE 1024
+#define PROCFS_NAME "mmaneg"
+
+static struct proc_dir_entry* proc_file;
+static char mmaneg_buf[PROCFS_MAX_SIZE + 1];
+
+static void listvma(void) {
+  struct task_struct* task = current;
+  struct mm_struct* mm = get_task_mm(task);
+  struct vm_area_struct* vma;
+
+  mmap_read_lock(mm);
+  VMA_ITERATOR(iter, mm, 0);
+  pr_info("VMA for process %d:\n", task->pid);
+  for_each_vma(iter, vma) {
+    pr_info("Start: 0x%lx, End: 0x%lx\n", vma->vm_start, vma->vm_end);
+  }
+  mmap_read_unlock(mm);
+}
+
+static void findpage(unsigned long addr) {
+  if (!virt_addr_valid(addr)) {
+    pr_warn("Virtual addr 0x%lx is invalid", addr);
+    return;
+  }
+  struct page* page = virt_to_page(addr);
+  pr_info("VA: 0x%lx, PA: 0x%llx\n", addr, page_to_phys(page));
+  put_page(page);
+}
+
+static void writeval(unsigned long addr, unsigned long val) {
+  if (put_user(val, (unsigned long*) addr)) {
+    pr_warn("Couldn't write to addr 0x%lx)\n", addr);
+  } else {
+    pr_info("Wrote %lu to addr 0x%lx", val, addr);
+  }
+}
+
+static ssize_t mmaneg_write(__always_unused struct file* file,
+                            const char __user* buf,
+                            size_t len,
+                            __always_unused loff_t* pos) {
+  if (len > PROCFS_MAX_SIZE) {
+    len = PROCFS_MAX_SIZE;
+  }
+  if (copy_from_user(mmaneg_buf, buf, len)) {
+    return -EFAULT;
+  }
+  mmaneg_buf[len] = '\0';
+  unsigned long addr = 0;
+  if (strncmp(mmaneg_buf, "listvma", 7) == 0) {
+    listvma();
+  } else if (strncmp(mmaneg_buf, "findpage", 8) == 0) {
+    if (sscanf(mmaneg_buf + 9, "%lx", &addr) != 1) {
+      goto unrecognized_arguments;
+    }
+    findpage(addr);
+  } else if (strncmp(mmaneg_buf, "writeval", 8) == 0) {
+    unsigned long val = 0;
+    if (sscanf(mmaneg_buf + 9, "%lx %lu", &addr, &val) != 2) {
+      goto unrecognized_arguments;
+    }
+    writeval(addr, val);
+  } else {
+    pr_warn("Invalid command: %s\n", mmaneg_buf);
+    return -EINVAL;
+  }
+  return (ssize_t) len;
+
+  unrecognized_arguments:
+  pr_warn("Invalid arguments: %s\n", mmaneg_buf);
+  return -EINVAL;
+}
+
+// Dummy funcs
+static int mmaneg_open(__always_unused struct inode* inode,
+                       __always_unused struct file* file) {
+  return 0;
+}
+
+static int mmaneg_release(__always_unused struct inode* inode,
+                          __always_unused struct file* file) {
+  return 0;
+}
+
+static loff_t mmaneg_lseek(__always_unused struct file* file,
+                           __always_unused loff_t loff,
+                           __always_unused int whence) {
+  return 0;
+}
+
+static ssize_t mmaneg_read(__always_unused struct file* file,
+                           __always_unused char __user* buf,
+                           __always_unused size_t len,
+                           __always_unused loff_t* pos) {
+  return -EACCES;
+}
+
+static struct proc_ops mmaneg_fops =
+    {
+        .proc_open = mmaneg_open,
+        .proc_read = mmaneg_read,
+        .proc_write = mmaneg_write,
+        .proc_lseek = mmaneg_lseek,
+        .proc_release = mmaneg_release,
+    };
+
+static int __init mmaneg_init(void) {
+  proc_file = proc_create(PROCFS_NAME, 222, NULL, &mmaneg_fops);
+  if (!proc_file) {
+    pr_err("Failed to create proc file (for some reason)");
+    return -ENOMEM;
+  }
+  return 0;
+}
+
+static void __exit mmaneg_exit(void) {
+  remove_proc_entry(PROCFS_NAME, NULL);
+}
+
+module_init(mmaneg_init)
+module_exit(mmaneg_exit)