imasusen · August 29, 2015 14:10 · Dec 1, 2014 · Dec 1, 2014 · Dec 1, 2014 · Dec 1, 2014
diff --git a/output_limit.cpp b/output_limit.cpp
@@ -49,7 +49,7 @@ int main() {
   while (read(pipefd[0], buf, bufsize) > 0) {
     output += buf;
 
-    // 出力量が多かったら子プロセスを殺す
+    // 出力量が多かったら子プロセスを終わらす
     if (strlen(output.c_str()) > output_limit) {
       kill(pid, SIGXFSZ);
       output += "\n出力過多";

diff --git a/output_limit.cpp b/output_limit.cpp
@@ -10,9 +10,8 @@
 using namespace std;
 
 int main() {
+  // パイプ(・㉨・)
   int pipefd[2]; // 0:read, 1:write
-
-  // パイプ
   pipe2(pipefd, O_CLOEXEC);
 
   const int pid = fork();

diff --git a/output_limit.cpp b/output_limit.cpp
@@ -42,12 +42,15 @@ int main() {
 
   close(pipefd[1]);
 
+  // 子プロセスが出力してるものを読んでく
   const int bufsize = 1024;
   const int output_limit = 128*1024;
   char buf[bufsize] = "";
   std::string output = "";
   while (read(pipefd[0], buf, bufsize) > 0) {
     output += buf;
+
+    // 出力量が多かったら子プロセスを殺す
     if (strlen(output.c_str()) > output_limit) {
       kill(pid, SIGXFSZ);
       output += "\n出力過多";

diff --git a/output_limit.cpp b/output_limit.cpp
@@ -31,6 +31,7 @@ int main() {
     old_stderr = dup(STDERR_FILENO);
     dup2(pipefd[1], STDOUT_FILENO);
     dup2(pipefd[1], STDERR_FILENO);
+
     while (1) {
       cout << "a";
     }

diff --git a/output_limit.cpp b/output_limit.cpp
@@ -4,44 +4,47 @@
 #include <unistd.h> // pipe2, dup, dup2, fork, read, close
 #include <fcntl.h>  // O_CLOEXEC flag
 #include <signal.h> // kill
- 
+
 #include <iostream>
 #include <string>
 using namespace std;
- 
+
 int main() {
   int pipefd[2]; // 0:read, 1:write
-  int old_stdout, old_stderr;
-  std::string output = "";
-
-  // 標準出力、標準エラーをパイプにリダイレクトさせる
+
+  // パイプ
   pipe2(pipefd, O_CLOEXEC);
-  old_stdout = dup(STDOUT_FILENO);
-  old_stderr = dup(STDERR_FILENO);
-  dup2(pipefd[1], STDOUT_FILENO);
-  dup2(pipefd[1], STDERR_FILENO);
-
+
   const int pid = fork();
   if (pid == -1) {
     perror("fork");
     return -1;
   }
   if (pid == 0) {
     // 子プロセス
+
+    close(pipefd[0]);
+
+    // 標準出力、標準エラーをパイプにリダイレクトさせる
+    int old_stdout, old_stderr;
+    old_stdout = dup(STDOUT_FILENO);
+    old_stderr = dup(STDERR_FILENO);
+    dup2(pipefd[1], STDOUT_FILENO);
+    dup2(pipefd[1], STDERR_FILENO);
     while (1) {
       cout << "a";
     }
     cout << "  (^-^)/" << endl;
   }
- 
+
   // 親プロセス
+
   close(pipefd[1]);
-  dup2(old_stdout, STDOUT_FILENO);
-  dup2(old_stderr, STDERR_FILENO);
-
+
   const int bufsize = 1024;
-  char buf[bufsize] = "";
   const int output_limit = 128*1024;
+  char buf[bufsize] = "";
+  std::string output = "";
   while (read(pipefd[0], buf, bufsize) > 0) {
     output += buf;
     if (strlen(output.c_str()) > output_limit) {
@@ -51,10 +54,9 @@ int main() {
     }
   }
   close(pipefd[0]);
-  close(old_stdout);
-  close(old_stderr);
-
+
+  // 子プロセスが出力した内容を表示
   cout << output << endl;
- 
+
   return 0;
 }
diff --git a/output_limit.cpp b/output_limit.cpp
@@ -0,0 +1,60 @@
+#include <sys/types.h>
+#include <stdio.h>  // perror
+#include <string.h> // strlen
+#include <unistd.h> // pipe2, dup, dup2, fork, read, close
+#include <fcntl.h>  // O_CLOEXEC flag
+#include <signal.h> // kill
+
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main() {
+  int pipefd[2]; // 0:read, 1:write
+  int old_stdout, old_stderr;
+  std::string output = "";
+
+  // 標準出力、標準エラーをパイプにリダイレクトさせる
+  pipe2(pipefd, O_CLOEXEC);
+  old_stdout = dup(STDOUT_FILENO);
+  old_stderr = dup(STDERR_FILENO);
+  dup2(pipefd[1], STDOUT_FILENO);
+  dup2(pipefd[1], STDERR_FILENO);
+
+  const int pid = fork();
+  if (pid == -1) {
+    perror("fork");
+    return -1;
+  }
+  if (pid == 0) {
+    // 子プロセス
+    while (1) {
+      cout << "a";
+    }
+    cout << "  (^-^)/" << endl;
+  }
+
+  // 親プロセス
+  close(pipefd[1]);
+  dup2(old_stdout, STDOUT_FILENO);
+  dup2(old_stderr, STDERR_FILENO);
+
+  const int bufsize = 1024;
+  char buf[bufsize] = "";
+  const int output_limit = 128*1024;
+  while (read(pipefd[0], buf, bufsize) > 0) {
+    output += buf;
+    if (strlen(output.c_str()) > output_limit) {
+      kill(pid, SIGXFSZ);
+      output += "\n出力過多";
+      break;
+    }
+  }
+  close(pipefd[0]);
+  close(old_stdout);
+  close(old_stderr);
+
+  cout << output << endl;
+
+  return 0;
+}