Add 'linux-syscall/' from commit '5a63d3bcf701f3c676b0f9d72aa9fd748d5…

…d7ef2'

git-subtree-dir: linux-syscall
git-subtree-mainline: cca4edb
git-subtree-split: 5a63d3b

linux-syscall/.gitignore

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+# Execute files
+mycalculator
+
+# Temporary files
+.dependency
+*.sh
+*.txt
+
+# Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+
+# Kernel Module Compile Results
+*.mod*
+*.cmd
+.tmp_versions/
+modules.order
+Module.symvers
+Mkfile.old
+dkms.conf

linux-syscall/Makefile

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+all: mycalculator
+CC=gcc
+mycalculator: mycalculator.c
+	$(CC) -o $@ $< 
+clean:
+	rm mycalculator

linux-syscall/README.md

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+# Calculation System Call
+
+4가지 연산 기능을 (덧셈(+), 뺄셈(-), 곱셈(*), 나머지(%)) 제공하는 신규 시스템 콜을 각각 추가하고, 추가된 시스템 콜을 호출하는 테스트 프로그램 구현
+
+## 0. Quick start
+
+``` bash
+git clone https://github.com/codejune/c-linux-syscall.git
+cd c-linux-syscall
+
+# 시스템 콜 추가
+cp sys_* {linux_kernel_dir}/kernel/
+cp kernel_Makefile {linux_kernel_dir}/kernel/Makefile
+cp syscalls.h {linux_kernel_dir}/include/linux/
+cp syscall_64.tbl {linux_kernel_dir}/arch/x86/entry/syscalls/
+# Do kernel build and reboot your system
+
+# 테스트 프로그램 빌드 및 실행
+make
+./mycalculator
+```
+
+## 1. Environment
+
+### Software
+
+- Ubuntu 20.04.3 LTS (x86_64)
+- Linux Kernel 5.11.22
+
+### Hardware
+
+- VM Instance
+- 4 Core 8 Thread
+- 8 GB RAM
+- 60 GB Storage
+
+## 2. Requirement
+
+### 조건
+
+- 4가지 이항 연산을 (덧셈(+), 뺄셈(-), 곱셈(*), 나머지(%)) 제공하는 새로운 시스템 콜 함수 4개를 커널에 등록
+- 테스트 프로그램을 (4가지 연산만을 수행하는 이항 계산기 프로그램) 작성하여 새롭게 등록된 시스템 콜 호출 확인
+
+### 출력
+
+- 테스트 프로그램
+
+    ``` bash
+    $ ./mycalculator 
+    >> 1+2
+    3
+    >> 3+5
+    8
+    >> 4+2
+    6
+    ```
+
+- 커널 로그
+
+    ``` bash
+    $ dmesg 
+
+    ...
+
+    [260376.527302] TCP: request_sock_TCP: Possible SYN flooding on port 22. Sending cookies.  Check SNMP counters.
+    [435056.713901] sys_my_add: a=1, b=2, result=3
+    [435059.119871] sys_my_add: a=3, b=5, result=8
+    [435061.672088] sys_my_add: a=4, b=2, result=6
+    ```

linux-syscall/kernel_Makefile

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+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel.
+#
+
+obj-y     = fork.o exec_domain.o panic.o \
+	    cpu.o exit.o softirq.o resource.o \
+	    sysctl.o capability.o ptrace.o user.o \
+	    signal.o sys.o umh.o workqueue.o pid.o task_work.o \
+	    extable.o params.o \
+	    kthread.o sys_ni.o nsproxy.o \
+	    notifier.o ksysfs.o cred.o reboot.o \
+	    async.o range.o smpboot.o ucount.o regset.o \
+	    sys_print_hello.o sys_my_add.o sys_my_subtract.o sys_my_multiply.o sys_my_modular.o
+
+obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o
+obj-$(CONFIG_MODULES) += kmod.o
+obj-$(CONFIG_MULTIUSER) += groups.o
+
+ifdef CONFIG_FUNCTION_TRACER
+# Do not trace internal ftrace files
+CFLAGS_REMOVE_irq_work.o = $(CC_FLAGS_FTRACE)
+endif
+
+# Prevents flicker of uninteresting __do_softirq()/__local_bh_disable_ip()
+# in coverage traces.
+KCOV_INSTRUMENT_softirq.o := n
+# Avoid KCSAN instrumentation in softirq ("No shared variables, all the data
+# are CPU local" => assume no data races), to reduce overhead in interrupts.
+KCSAN_SANITIZE_softirq.o = n
+# These are called from save_stack_trace() on slub debug path,
+# and produce insane amounts of uninteresting coverage.
+KCOV_INSTRUMENT_module.o := n
+KCOV_INSTRUMENT_extable.o := n
+KCOV_INSTRUMENT_stacktrace.o := n
+# Don't self-instrument.
+KCOV_INSTRUMENT_kcov.o := n
+# If sanitizers detect any issues in kcov, it may lead to recursion
+# via printk, etc.
+KASAN_SANITIZE_kcov.o := n
+KCSAN_SANITIZE_kcov.o := n
+UBSAN_SANITIZE_kcov.o := n
+CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector
+
+obj-y += sched/
+obj-y += locking/
+obj-y += power/
+obj-y += printk/
+obj-y += irq/
+obj-y += rcu/
+obj-y += livepatch/
+obj-y += dma/
+obj-y += entry/
+
+obj-$(CONFIG_KCMP) += kcmp.o
+obj-$(CONFIG_FREEZER) += freezer.o
+obj-$(CONFIG_PROFILING) += profile.o
+obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-y += time/
+obj-$(CONFIG_FUTEX) += futex.o
+obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
+obj-$(CONFIG_SMP) += smp.o
+ifneq ($(CONFIG_SMP),y)
+obj-y += up.o
+endif
+obj-$(CONFIG_UID16) += uid16.o
+obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_MODULE_SIG) += module_signing.o
+obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o
+obj-$(CONFIG_KALLSYMS) += kallsyms.o
+obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
+obj-$(CONFIG_CRASH_CORE) += crash_core.o
+obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
+obj-$(CONFIG_KEXEC) += kexec.o
+obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
+obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o
+obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
+obj-$(CONFIG_COMPAT) += compat.o
+obj-$(CONFIG_CGROUPS) += cgroup/
+obj-$(CONFIG_UTS_NS) += utsname.o
+obj-$(CONFIG_USER_NS) += user_namespace.o
+obj-$(CONFIG_PID_NS) += pid_namespace.o
+obj-$(CONFIG_IKCONFIG) += configs.o
+obj-$(CONFIG_IKHEADERS) += kheaders.o
+obj-$(CONFIG_SMP) += stop_machine.o
+obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
+obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
+obj-$(CONFIG_AUDITSYSCALL) += auditsc.o audit_watch.o audit_fsnotify.o audit_tree.o
+obj-$(CONFIG_GCOV_KERNEL) += gcov/
+obj-$(CONFIG_KCOV) += kcov.o
+obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o
+obj-$(CONFIG_KGDB) += debug/
+obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
+obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o
+obj-$(CONFIG_SECCOMP) += seccomp.o
+obj-$(CONFIG_RELAY) += relay.o
+obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
+obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
+obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
+obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
+obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_FUNCTION_TRACER) += trace/
+obj-$(CONFIG_TRACING) += trace/
+obj-$(CONFIG_TRACE_CLOCK) += trace/
+obj-$(CONFIG_RING_BUFFER) += trace/
+obj-$(CONFIG_TRACEPOINTS) += trace/
+obj-$(CONFIG_IRQ_WORK) += irq_work.o
+obj-$(CONFIG_CPU_PM) += cpu_pm.o
+obj-$(CONFIG_BPF) += bpf/
+obj-$(CONFIG_KCSAN) += kcsan/
+obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o
+obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call.o
+
+obj-$(CONFIG_PERF_EVENTS) += events/
+
+obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
+obj-$(CONFIG_PADATA) += padata.o
+obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
+obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
+obj-$(CONFIG_TORTURE_TEST) += torture.o
+
+obj-$(CONFIG_HAS_IOMEM) += iomem.o
+obj-$(CONFIG_RSEQ) += rseq.o
+obj-$(CONFIG_WATCH_QUEUE) += watch_queue.o
+
+obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o
+obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o
+
+CFLAGS_stackleak.o += $(DISABLE_STACKLEAK_PLUGIN)
+obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o
+KASAN_SANITIZE_stackleak.o := n
+KCSAN_SANITIZE_stackleak.o := n
+KCOV_INSTRUMENT_stackleak.o := n
+
+obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o
+
+$(obj)/configs.o: $(obj)/config_data.gz
+
+targets += config_data config_data.gz
+$(obj)/config_data.gz: $(obj)/config_data FORCE
+	$(call if_changed,gzip)
+
+filechk_cat = cat $<
+
+$(obj)/config_data: $(KCONFIG_CONFIG) FORCE
+	$(call filechk,cat)
+
+$(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz
+
+quiet_cmd_genikh = CHK     $(obj)/kheaders_data.tar.xz
+      cmd_genikh = $(CONFIG_SHELL) $(srctree)/kernel/gen_kheaders.sh $@
+$(obj)/kheaders_data.tar.xz: FORCE
+	$(call cmd,genikh)
+
+clean-files := kheaders_data.tar.xz kheaders.md5

linux-syscall/mycalculator.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/kernel.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <string.h>
+#define BUFFER_SIZE 256
+#define SYS_MY_ADD 443
+#define SYS_MY_SUBTRACT 444
+#define SYS_MY_MULTIPLY 445
+#define SYS_MY_MODULAR 446
+int main(void)
+{
+	char op;
+	char a[BUFFER_SIZE], b[BUFFER_SIZE];
+
+	while(true)
+	{
+		printf(">> ");
+		scanf("%[^+-*%]%c%[^\n]", a, &op, b);
+		getchar();
+		switch(op)
+		{
+			case '+':
+				printf("%ld\n", syscall(SYS_MY_ADD, atoi(a), atoi(b)));
+				break;
+			case '-':
+				printf("%ld\n", syscall(SYS_MY_SUBTRACT, atoi(a), atoi(b)));
+				break;
+			case '*':
+				printf("%ld\n", syscall(SYS_MY_MULTIPLY, atoi(a), atoi(b)));
+				break;
+			case '%':
+				printf("%ld\n", syscall(SYS_MY_MODULAR, atoi(a), atoi(b)));
+				break;	
+		}
+	}
+	exit(EXIT_SUCCESS);
+}
+

linux-syscall/sys_my_add.c

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+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+asmlinkage long sys_my_add(long a, long b){
+	printk("sys_my_add: a=%ld, b=%ld, result=%ld\n", a, b, a+b);
+	return a + b;
+}
+
+SYSCALL_DEFINE2(my_add, long, a, long, b)
+{
+	return sys_my_add(a, b);
+}

linux-syscall/sys_my_modular.c

@@ -0,0 +1,12 @@
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+asmlinkage long sys_my_modular(long a, long b)
+{
+	printk("sys_my_modular: a=%ld, b=%ld, result=%ld\n", a, b, a%b);
+	return a % b;
+}
+SYSCALL_DEFINE2(my_modular, long, a, long, b)
+{
+	return sys_my_modular(a, b);
+}
+

linux-syscall/sys_my_multiply.c

@@ -0,0 +1,12 @@
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+asmlinkage long sys_my_multiply(long a, long b)
+{
+	printk("sys_my_multiply: a=%ld, b=%ld, result=%ld\n", a, b, a*b);
+	return a * b;
+}
+
+SYSCALL_DEFINE2(my_multiply, long, a, long, b)
+{
+	return sys_my_multiply(a, b);
+}

linux-syscall/sys_my_subtract.c

@@ -0,0 +1,12 @@
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+asmlinkage long sys_my_subtract(long a, long b)
+{
+	printk("sys_my_subtract: a=%ld, b=%ld, result=%ld\n", a, b, a-b);
+	return a - b;
+}
+SYSCALL_DEFINE2(my_subtract, long, a, long, b)
+{
+	return sys_my_subtract(a, b);
+}
+