feat(os): ostep intro: cpu.c mem.c

.gitignore

@@ -19,4 +19,6 @@ node_modules
 yarn-error.log
 .history
 .vscode
-.DS_Store
+.DS_Store
+
+nohup.out

c++/README.md

@@ -4,4 +4,4 @@ cd到当前目录
 
 执行  
 
-    docker run -it --rm --entrypoint /bin/sh -v `pwd`:/code bluewaitor/linuxc
+    docker run -it --rm --entrypoint /bin/sh -v $(pwd):/code bluewaitor/linuxc

os/ostep/README.md

@@ -0,0 +1,30 @@
+# Operating Systems: Three Easy Pieces
+
+[网址](https://pages.cs.wisc.edu/~remzi/OSTEP/)
+
+[代码地址](https://github.com/remzi-arpacidusseau/ostep-code)
+
+## 使用docker
+
+```shell
+docker run -it --rm --entrypoint /bin/sh -v $(pwd):/code bluewaitor/linuxc
+```
+
+## Intro
+
+```shell
+gcc -o cpu cpu.c -Wall
+./cpu A
+
+./cpu A & ./cpu B & ./cpu C & ./cpu D & # 后台运行
+
+# 结束方法
+# ps 查看进程
+kill -9 PID
+
+# fg 将进程放到前台
+# ctrl + c 结束进程
+
+# 关掉整个terminal
+
+```

os/ostep/intro/common.h

@@ -0,0 +1,21 @@
+#ifndef __COMMON_H__
+#define __COMMON_H__
+
+#include <sys/time.h>
+#include <assert.h>
+
+double GetTime() {
+    struct timeval t;
+    int rc = gettimeofday(&t, NULL);
+    assert(rc == 0);
+    return (double) t.tv_sec + (double) t.tv_usec / 1e6;
+}
+
+void Spin(int howlong) {
+    double t = GetTime();
+    while (GetTime() - t < (double) howlong)
+        ; // do nothing in loop
+}
+
+
+#endif

os/ostep/intro/cpu.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "common.h"
+
+int main(int argc, char* argv[]) {
+    setbuf(stdout, NULL); // 使用nohup的时候，需要设置这个，否则会出现输出不到文件的情况
+
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+        exit(1);
+    }
+    for (int i = 0; i < argc; i ++) {
+        printf("argv[%d] = %s\n", i, argv[i]);
+    }
+
+    char *str = argv[1];
+
+    while (1)
+    {
+        Spin(1);
+        printf("%s\n", str);
+    }
+
+    return 0;
+}

os/ostep/intro/mem.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include "common.h"
+
+int main(int argc, char *argv[]) {
+    int *p = malloc(sizeof(int));
+    assert(p != NULL);
+    printf("(%d) address pointed to by p: %p\n", getpid(), p);
+    *p = 0;
+    while (1)
+    {
+        Spin(1);
+        *p = *p + 1;
+        printf("(%d) p: %d\n", getpid(), *p);
+    }
+    return 0;
+}