feat: busybox image

fightinggg · Jun 1, 2021 · 1d55e73 · 1d55e73
1 parent 9e0e3ac
commit 1d55e73
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Showing 2 changed files with 85 additions and 37 deletions.
diff --git a/src/main.cpp b/src/main.cpp
@@ -1,6 +1,14 @@
+#include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
 #include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
@@ -15,24 +23,31 @@
 #include "utils/StringUtils.hpp"
 
 using namespace std;
-#define FIBER_STACK 8192
+#define FIBER_STACK 81920
+String busyBoxDir = "/root/src/busybox";
+
+String getErr() {
+  char s[100];
+  sprintf(s, "(%d)%s", errno, strerror(errno));
+  return String(s);
+}
 
 void prepareContainer(RunParam *runParam) {
   // create cpu subsystem
   char cmd[128];
   Vector<String> cmdList = {"cd /sys/fs/cgroup/cpu ", "&& mkdir %s ",
                             "&& cd %s ", "&& echo %d > cpu.cfs_quota_us ",
                             "&& echo 50000 > cpu.cfs_period_us "};
-  sprintf(cmd, StringUtils::join(cmdList).data(),
+  sprintf(cmd, StringUtils::join(cmdList, " ").data(),
           runParam->getContainerId().data(), runParam->getContainerId().data(),
           int(runParam->getCpus() * 50000));
   system(cmd);
 
   // create memory subsystem
-  cmdList = {"cd /sys/fs/cgroup/memory ", "&& mkdir %s ",
-                            "&& cd %s ", "&& echo %d > memory.limit_in_bytes ",
-                            "&& echo %d > memory.memsw.limit_in_bytes "};
-  sprintf(cmd, StringUtils::join(cmdList).data(),
+  cmdList = {"cd /sys/fs/cgroup/memory ", "&& mkdir %s ", "&& cd %s ",
+             "&& echo %d > memory.limit_in_bytes ",
+             "&& echo %d > memory.memsw.limit_in_bytes "};
+  sprintf(cmd, StringUtils::join(cmdList, " ").data(),
           runParam->getContainerId().data(), runParam->getContainerId().data(),
           int(runParam->getMemory()), int(runParam->getMemorySwap()));
   system(cmd);
@@ -52,39 +67,58 @@ int doContainer(void *param) {
           runParam->getContainerId().data());
   system(cmd);
 
-  // mount proc system
+  // mount proc system, then container could not find others process
   if (mount("proc", "/proc", "proc", MS_NOEXEC | MS_NOSUID | MS_NODEV, NULL)) {
     cerr << "mount proc error" << endl;
     exit(-1);
   }
 
-  if (runParam->getImage() == "centos") {
-    vector<String> v = runParam->getExec();
-
-    switch (v.size()) {
-      case 0:
-        cerr << "no params ???" << endl;
-        exit(-1);
-      case 1:
-        execlp(v[0].data(), nullptr);
-        break;
-      case 2:
-        execlp(v[0].data(), v[1].data(), NULL);
-        break;
-      case 3:
-        execlp(v[0].data(), v[1].data(), v[2].data(), NULL);
-        break;
-      case 4:
-        execlp(v[0].data(), v[1].data(), v[2].data(), v[3].data(), NULL);
-        break;
-      default:
-        cerr << "too many params, only four params support" << endl;
-        exit(-1);
-    }
-    cerr << "exec error: " << endl;
+  // mount busyBox 1. change workdir
+  if (chdir(busyBoxDir.data())) {
+    cerr << "chdir to busyBoxDir error" << endl;
+    exit(-1);
+  }
+  // mount busyBox 2. mount busyBox
+  if (mount(busyBoxDir.data(), busyBoxDir.data(), "bind", MS_BIND | MS_REC,
+            NULL)) {
+    cerr << "mount busyBox error" << endl;
+    exit(-1);
+  }
+  String privotRootName = ".pivot_root" + runParam->getContainerId();
+  String privotRoot = busyBoxDir + "/" + privotRootName;
+  // mount busyBox 3. mkdir put_old
+  if (mkdir(privotRoot.data(), S_IRWXU | S_IRWXG | S_IRWXO)) {
+    cerr << "mkdir privotRoot error" << endl;
+    exit(-1);
+  }
+  // mount busyBox 4. privot_root()
+  if (syscall(SYS_pivot_root, busyBoxDir.data(), privotRoot.data())) {
+    cerr << "privot_root error" << endl;
+    exit(-1);
+  }
+  // mount busyBox 5. to dir /
+  if (chdir("/")) {
+    cerr << "chdir to / error" << endl;
+    exit(-1);
+  }
+  // mount busyBox 6. unmount .privot_root
+  if (umount2(("/" + privotRootName).data(), MNT_DETACH)) {
+    cerr << "unmount .pivot_root  error " << getErr() << endl;
     exit(-1);
+  }
+  // mount busyBox 7. delete dir
+  if (rmdir(("/" + privotRootName).data())) {
+    cerr << "rm .pivot_root  error " << getErr() << endl;
+    exit(-1);
+  }
+
+  if (runParam->getImage() == "busybox") {
+    vector<String> v = runParam->getExec();
+    cout << "container begin: " << StringUtils::join(v, " ") << endl;
+    return system(StringUtils::join(v, " ").data());
   } else {
-    cerr << "could not find image '" << runParam->getImage() << "'" << endl;
+    cerr << "could not find image '" << runParam->getImage()
+         << "', you can use image 'busybox'" << endl;
     exit(-1);
   }
 }
@@ -100,6 +134,19 @@ int main(int argc, char *argv[]) {
   prepareContainer((RunParam *)param);
   int pid = clone(doContainer, (char *)stack + FIBER_STACK, containerFlag,
                   param);  //创建子线程
-  waitpid(pid, NULL, 0);
-  cout << "container exit, thanks for using pocker " << endl;
+  int sonStatus;
+  if (waitpid(pid, &sonStatus, 0) != pid) {
+    cerr << "container error " << getErr() << endl;
+    exit(-1);
+  }
+  if (WIFEXITED(sonStatus)) {
+    printf("container exited, status=%d\n", WEXITSTATUS(sonStatus));
+  } else if (WIFSIGNALED(sonStatus)) {
+    printf("container killed by signal %d\n", WTERMSIG(sonStatus));
+  } else if (WIFSTOPPED(sonStatus)) {
+    printf("container stopped by signal %d\n", WSTOPSIG(sonStatus));
+  } else if (WIFCONTINUED(sonStatus)) {
+    printf("container continued\n");
+  }
+  cout << " thanks for using pocker" << endl;
 }
diff --git a/src/utils/StringUtils.hpp b/src/utils/StringUtils.hpp
@@ -3,10 +3,11 @@
 
 class StringUtils {
  public:
-  static String join(const Vector<String>&strings) {
+  static String join(const Vector<String>& strings, String split) {
     String res;
-    for (String s : strings) {
-      res += s;
+    for (int i = 0; i < strings.size(); i++) {
+      res += strings[i];
+      if (i != 0) res += split;
     }
     return res;
   }