week11

week11/.gitignore

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+lofs*

week11/ex1.sh

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+#!/bin/sh
+
+sudo umount lofsdisk
+sudo losetup -d $(sudo losetup -j lofs.img | awk -F ':' '{ print $1; }')
+rm -rf lofsdisk lofs.img
+
+dd if=/dev/zero of=lofs.img bs=100M count=1
+mkfs.ext4 lofs.img
+lodevice=$(sudo losetup -fP --show lofs.img)
+mkdir lofsdisk
+sudo mount "$lodevice" lofsdisk
+sudo chmod -R 777 lofsdisk

week11/ex2.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/stat.h>
+
+int main() {
+    DIR *d = opendir("/");
+    if (d == NULL) {
+        perror("opendir");
+        exit(1);
+    }
+
+    struct dirent *entry;
+    while ((entry = readdir(d))!= NULL) {
+        if (entry->d_name[0] == '.')
+            continue;
+
+        printf("%s ", entry->d_name);
+    }
+}

week11/ex2.sh

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+#!/bin/sh
+
+chmod +x ex1.sh
+./ex1.sh
+
+echo "Amirlan" > lofsdisk/file1
+echo "Sharipov" > lofsdisk/file2
+
+mkdir lofsdisk/usr
+mkdir lofsdisk/usr/bin
+mkdir lofsdisk/usr/lib
+mkdir lofsdisk/usr/lib64
+
+# I am using Arch Linux, that's why some libraries may differ from Ubuntu
+# Sorry for the inconvinience
+
+cp /bin/bash /bin/ls /bin/echo /bin/cat lofsdisk/usr/bin
+cp /lib/libreadline.so* lofsdisk/usr/lib/
+cp /lib/libdl.so.2* lofsdisk/usr/lib/
+cp /lib/libc.so* lofsdisk/usr/lib/
+cp /lib/libncursesw.so* lofsdisk/usr/lib/
+cp /lib/libcap.so.2* lofsdisk/usr/lib/
+cp /lib64/ld-linux-x86-64.so.2 lofsdisk/usr/lib64/
+
+# symbolic links contain just the path, so after chroot they will pick the directories inside lofsdisk
+ln -sf /usr/lib lofsdisk/lib
+ln -sf /usr/lib64 lofsdisk/lib64
+ln -sf /usr/bin lofsdisk/bin
+
+gcc ex2.c -o ex2.out
+cp ex2.out lofsdisk
+
+printf "\nW/ CHROOT\n" > ex2.txt
+sudo chroot lofsdisk /ex2.out >> ex2.txt
+printf "\nW/O CHROOT\n" >> ex2.txt
+./ex2.out >> ex2.txt

week11/ex2.txt

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+
+W/ CHROOT
+usr lib64 lost+found lib bin file1 file2 ex2.out 
+W/O CHROOT
+tmp var opt home dev run etc bin lost+found lib sys sbin lib64 proc usr mnt root boot srv