Add checker for lab 4

Add the checker which will test for memory leaks.

Signed-off-by: Mihnea Firoiu <[email protected]>

chapters/data/investigate-memory/guides/memory-leak/.gitignore

@@ -1,3 +1 @@
-/memory_leak
-/memory_leak_malloc
-/mem.trace
+support/

chapters/data/investigate-memory/guides/memory-leak/Makefile

@@ -0,0 +1,10 @@
+PYTHON = python3
+SCRIPT = generate_skels.py
+
+skels:
+	mkdir -p support/src/
+	$(PYTHON) $(SCRIPT) --input ./solution/src/ --output ./support/src/
+	cp -r solution/tests/ support/tests
+
+clean:
+	rm -rf support/

chapters/data/investigate-memory/guides/memory-leak/README.md

@@ -1,19 +1,19 @@
 # Memory Leaks
 
-A memory leak occurs when we lose reference to a memory area.
-That is, a pointer used to point to a memory area.
-And then it's pointing to a new memory area and the old memory area is lost.
+A memory leak happens when a memory region is allocated but no longer accessible.
+This typically occurs when a pointer that referenced a memory area is redirected to a new memory location, leaving the original memory area unreachable and unable to be freed.
 
-Enter the `chapters/data/investigate-memory/guides/memory-leak/support` directory.
+Enter the `chapters/data/investigate-memory/guides/memory-leak` folder, run `make skels`.
+Enter the `chapters/data/investigate-memory/guides/memory-leak/support/src` directory.
 It stores two files showing memory leaks:
 
 - one in C++: `memory_leak.cpp`
-- one in C: `memory_leak_malloc`
+- one in C: `memory_leak_malloc.c`
 
 Let's build and run the two executables:
 
 ```console
-student@os:~/.../memory-leak/support$ make
+student@os:~/.../memory-leak/support/src$ make
 g++    -c -o memory_leak.o memory_leak.cpp
 cc   memory_leak.o  -lstdc++ -o memory_leak
 cc    -c -o memory_leak_malloc.o memory_leak_malloc.c
@@ -23,25 +23,25 @@ cc   memory_leak_malloc.o  -lstdc++ -o memory_leak_malloc
 Running them yields similar output:
 
 ```console
-student@os:~/.../memory-leak/support$ ./memory_leak
-Andrei Popescu is 22 years old and likes Linux
-Ioana David is 23 years old and likes macOS
-student@os:~/.../lab/support/memory-leak$ ./memory_leak_malloc
-Andrei Popescu is 22 years old and likes Linux
-Ioana David is 23 years old and likes macOS
+student@os:~/.../memory-leak/support/src$ ./memory_leak
+Linus Torvalds is 22 years old and likes Linux
+Steve Jobs is 23 years old and likes macOS
+student@os:~/.../memory-leak/support/src$ ./memory_leak_malloc
+Linus Torvalds is 22 years old and likes Linux
+Steve Jobs is 23 years old and likes macOS
 ```
 
 We investigate the memory leaks of the two programs by using [Valgrind](https://valgrind.org/):
 
 ```console
-student@os:~/.../memory-leak/support$ valgrind ./memory_leak
+student@os:~/.../memory-leak/support/src$ valgrind ./memory_leak
 ==22362== Memcheck, a memory error detector
 ==22362== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
 ==22362== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
 ==22362== Command: ./memory_leak
 ==22362==
-Andrei Popescu is 22 years old and likes Linux
-Ioana David is 23 years old and likes macOS
+Linus Torvalds is 22 years old and likes Linux
+Steve Jobs is 23 years old and likes macOS
 ==22362==
 ==22362== HEAP SUMMARY:
 ==22362==     in use at exit: 72 bytes in 1 blocks
@@ -58,14 +58,14 @@ Ioana David is 23 years old and likes macOS
 ==22362== For counts of detected and suppressed errors, rerun with: -v
 ==22362== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
 
-student@os:~/.../memory-leak/support$ valgrind ./memory_leak_malloc
+student@os:~/.../memory-leak/support/src$ valgrind ./memory_leak_malloc
 ==22369== Memcheck, a memory error detector
 ==22369== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
 ==22369== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
 ==22369== Command: ./memory_leak_malloc
 ==22369==
-Andrei Popescu is 22 years old and likes Linux
-Ioana David is 23 years old and likes macOS
+Linus Torvalds is 22 years old and likes Linux
+Steve Jobs is 23 years old and likes macOS
 ==22369==
 ==22369== HEAP SUMMARY:
 ==22369==     in use at exit: 148 bytes in 1 blocks
@@ -93,15 +93,15 @@ We probably also require to preload the libc `malloc` debugging library, so we u
 Note that the file path used for `LD_PRELOAD` may need to be updated, depending on your distribution:
 
 ```console
-student@os:~/.../memory-leak/support$ LD_PRELOAD=/lib/x86_64-linux-gnu/libc_malloc_debug.so.0 MALLOC_TRACE=mem.trace ./memory_leak_malloc
-Andrei Popescu is 22 years old and likes Linux
-Ioana David is 23 years old and likes macOS
+student@os:~/.../memory-leak/support/src$ LD_PRELOAD=/lib/x86_64-linux-gnu/libc_malloc_debug.so.0 MALLOC_TRACE=mem.trace ./memory_leak_malloc
+Linus Torvalds is 22 years old and likes Linux
+Steve Jobs is 23 years old and likes macOS
 ```
 
 Subsequently, we use the `mtrace` tool to show information about the leaked data:
 
 ```console
-student@os:~/.../memory-leak/support$ mtrace ./memory_leak_malloc mem.trace
+student@os:~/.../memory-leak/support/src$ mtrace ./memory_leak_malloc mem.trace
 
 Memory not freed:
 -----------------
@@ -119,4 +119,28 @@ Valgrind is however more powerful: it works on different types of memory (not on
 1. Print the size of the `Student` class and the `struct student` structure to see if it equates to the leak shown by Valgrind.
 
 1. Solve the memory leaks in both programs.
-   Validate with Valgrind.
+   Run the checker (`./checker.sh` in the `memory-leak/support/tests/` folder) to check your results.
+
+   Sample run:
+
+```console
+student@so:~/.../support/tests/$ ./checker.sh
+make: Entering directory '/home/student/operating-systems/chapters/data/investigate-memory/guides/memory-leak/support/src'
+g++    -c -o memory_leak.o memory_leak.cpp
+cc   memory_leak.o  -lstdc++ -o memory_leak
+cc    -c -o memory_leak_malloc.o memory_leak_malloc.c
+cc   memory_leak_malloc.o  -lstdc++ -o memory_leak_malloc
+make: Leaving directory '/home/student/operating-systems/chapters/data/investigate-memory/guides/memory-leak/support/src'
+-------------------------------------------------
+Checking memory leaks for C executable: ../src/memory_leak
+C executable is leak-free!
+
+Points for ../src/memory_leak: 50/50
+-------------------------------------------------
+Checking memory leaks for C++ executable: ../src/memory_leak_malloc
+C++ executable is leak-free!
+
+Points for ../src/memory_leak_malloc: 50/50
+-------------------------------------------------
+Total Points: 100/100
+```

chapters/data/investigate-memory/guides/memory-leak/generate_skels.py

@@ -0,0 +1,151 @@
+#!/usr/bin/python3 -u
+# SPDX-License-Identifier: BSD-3-Clause
+
+import sys
+import argparse
+import os.path
+import re
+
+
+def process_file(src, dst, pattern, replace, remove, replace_pairs, end_string=None):
+    if not pattern or not replace or not remove:
+        print(
+            f"ERROR: The script behaviour is not properly specified for {src}",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    fin = open(src, "r")
+    fout = open(dst, "w")
+    remove_lines = 0
+    skip_lines = 0
+    uncomment_lines = 0
+    end_found = True
+
+    for l in fin.readlines():
+        # Skip generation of file.
+        if "SKIP_GENERATE" in l:
+            fout.close()
+            os.remove(dst)
+            return
+
+        if end_string and end_found == False:
+            fout.write(l)
+            if end_string in l:
+                end_found = True
+            continue
+
+        if remove_lines > 0:
+            remove_lines -= 1
+            continue
+
+        if skip_lines > 0:
+            skip_lines -= 1
+            m = re.search(pattern, l)
+            if m:
+                l = "%s%s\n" % (m.group(1), m.group(3))
+                fout.write(l)
+            continue
+
+        if uncomment_lines > 0:
+            uncomment_lines -= 1
+            for fro, to in replace_pairs:
+                l = re.sub(fro, to, l)
+            fout.write(l)
+            continue
+
+        m = re.search(pattern, l)
+        if m:
+            if m.group(2):
+                skip_lines = int(m.group(2))
+            else:
+                skip_lines = 1
+
+            if end_string and end_string not in l:
+                end_found = False
+
+            l = "%s%s\n" % (m.group(1), m.group(3))
+
+        m = re.search(replace, l)
+        if m:
+            if m.group(2):
+                uncomment_lines = int(m.group(2))
+            else:
+                uncomment_lines = 1
+            continue
+
+        m = re.search(remove, l)
+        if m:
+            if m.group(2):
+                remove_lines = int(m.group(2))
+            else:
+                remove_lines = 1
+            continue
+
+        fout.write(l)
+
+    fout.close()
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Generate skeletons sources from reference solution sources"
+    )
+    parser.add_argument(
+        "--input", help="input directory to process files", required=True
+    )
+    parser.add_argument(
+        "--output", help="output directory to copy processed files", required=True
+    )
+    args = parser.parse_args()
+
+    for root, dirs, files in os.walk(args.input):
+        new_root = os.path.join(args.output, os.path.relpath(root, args.input))
+        for d in dirs:
+            os.makedirs(os.path.join(new_root, d), exist_ok=True)
+
+        for src in files:
+            if (
+                re.match("Makefile.*$", src)
+                or re.match(r".*\.sh$", src)
+                or re.match(r".*\.[sS]$", src)
+                or re.match(r".*\.py$", src)
+            ):
+                pattern = r"(^\s*#\s*TODO)( [0-9]*)(:.*)"
+                replace = r"(^\s*#\s*REPLACE)( [0-9]*)"
+                remove = r"(^\s*#\s*REMOVE)( [0-9]*)"
+                replace_pairs = [("# ", "")]
+                end_string = None
+            elif re.match(r".*\.asm$", src):
+                pattern = r"(^\s*;\s*TODO)( [0-9]*)(:.*)"
+                replace = r"(^\s*;\s*REPLACE)( [0-9]*)"
+                remove = r"(^\s*;\s*REMOVE)( [0-9]*)"
+                replace_pairs = [("; ", "")]
+                end_string = None
+            elif (
+                re.match(r".*\.[ch]$", src)
+                or re.match(r".*\.cpp$", src)
+                or re.match(r".*\.hpp$", src)
+            ):
+                pattern = r"(.*/\*\s*TODO)([ 0-9]*)(:.*)"
+                replace = r"(.*/\*\s*REPLACE)( [0-9]*)"
+                remove = r"(.*/\*\s*REMOVE)( [0-9]*)"
+                replace_pairs = [(r"/\* ", ""), (r" \*/", "")]
+                end_string = "*/"
+            elif re.match(r".*\.d$", src):
+                pattern = r"(.*//\s*TODO)([ 0-9]*)(:.*)"
+                replace = r"(.*//\s*REPLACE)( [0-9]*)"
+                remove = r"(.*//\s*REMOVE)( [0-9]*)"
+                replace_pairs = [(r"// ", "")]
+                end_string = None
+            else:
+                continue
+
+            dst = os.path.join(new_root, src)
+            src = os.path.join(root, src)
+            print(dst)
+            process_file(src, dst, pattern, replace, remove, replace_pairs, end_string)
+
+
+if __name__ == "__main__":
+    sys.exit(main())

chapters/data/investigate-memory/guides/memory-leak/support/memory_leak.cpp → chapters/data/investigate-memory/guides/memory-leak/solution/src/memory_leak.cpp

@@ -28,13 +28,20 @@ int main(void)
 {
 	Student *s;
 
-	s = new Student("Andrei Popescu", 22, "Linux");
+	s = new Student("Linus Torvalds", 22, "Linux");
 	s->Print();
 
-	s = new Student("Ioana David", 23, "macOS");
+	/* TODO 1: Solve memory leaks. */
+	delete s;
+
+	s = new Student("Steve Jobs", 23, "macOS");
 	s->Print();
 
+	/* REMOVE 2 */
 	delete s;
 
+	/* TODO 1: Print size of student. */
+	std::cout << "Size of class Student: " << sizeof(Student) << "\n";
+
 	return 0;
 }

chapters/data/investigate-memory/guides/memory-leak/support/memory_leak_malloc.c → chapters/data/investigate-memory/guides/memory-leak/solution/src/memory_leak_malloc.c

@@ -31,14 +31,21 @@ int main(void)
 	mtrace();
 
 	s = malloc(sizeof(*s));
-	init_student(s, "Andrei Popescu", 22, "Linux");
+	init_student(s, "Linus Torvalds", 22, "Linux");
 	print_student(s);
 
+	/* TODO 1: Solve memory leaks. */
+	free(s);
+
 	s = malloc(sizeof(*s));
-	init_student(s, "Ioana David", 23, "macOS");
+	init_student(s, "Steve Jobs", 23, "macOS");
 	print_student(s);
 
+	/* REMOVE 2 */
 	free(s);
 
+	/* TODO 1: Print size of student. */
+	printf("Size of struct student: %ld\n", sizeof(struct student));
+
 	return 0;
 }