Question

我已经为C中的HTTP服务器编写了一些代码。它适用于少量客户端（可能在100-500ish范围内），但当被要求面对大量并发用户时，它会耗尽记忆。我想知道为什么会这样。

这是从客户端读取数据然后返回响应的代码。顺便说一句，客户端和服务器套接字是非阻塞的：

int handle_client(char *root, int c) {

    int size = sizeof(char) * BUFSIZ + 1, len = strlen(SEND_HTTP_NOT_FOUND);
    char *buffer = malloc(size), *data = NULL, not_found_error[200] = SEND_HTTP_NOT_FOUND, internal_error[200] = SEND_HTTP_INTERNAL_SERVER_ERROR;

    if (!buffer) {
        log_error(errno);
        return -1;
    }

    bzero(buffer, size);

    while (1) {
        if (read(c, buffer, size) <= 0) {
             if (errno != EAGAIN && errno != EWOULDBLOCK) {
                 log_error(errno);
                 free(buffer);
                 if (c) close(c);
                 return -1;
             } else {
                 int not_found = 0;
                 data = parse_content(root, buffer, not_found);
                 if (!data) {
                      if (not_found) {
                          if (write(c, not_found_error, len) <= 0)
                               log_error(errno);
                      } else {
                          if (write(c, internal_error, len) <= 0)
                               log_error(errno);
                      }

                      free(buffer);
                      if (c) close(c);
                      return -1;
                  }
                  break;
              }
         }
    }

    if (write(c, data, strlen(data)) <= 0) {
         if (errno != EAGAIN && errno != EWOULDBLOCK) {
              log_error(errno);
              close(c);
              free(data);
              free(buffer);
              return -1;
         }
     }

     close(c);
     free(data);
     free(buffer);

     return 0;
}

为了测试此代码，我使用了siege：

siege --file=try_me.txt -c 1000 -v

try_me.txt 2个请求索引页面的URL和一个名为test.txt的文件。经过一段时间用1000个并发用户轰炸它后，会发生这种情况：

siege输出：

 HTTP/1.1 200     0.14 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.14 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.14 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.14 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.14 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.13 secs:     158 bytes ==> GET  /test.txt
 HTTP/1.1 200     0.13 secs:     225 bytes ==> GET  /
 HTTP/1.1 200     0.14 secs:     225 bytes ==> GET  /
 HTTP/1.1 500     0.14 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.14 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.14 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     1.13 secs:      41 bytes ==> GET  /test.txt
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /test.txt
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     1.12 secs:      41 bytes ==> GET  /test.txt
 HTTP/1.1 500     0.12 secs:      41 bytes ==> GET  /test.txt
 HTTP/1.1 500     0.13 secs:      41 bytes ==> GET  /
 HTTP/1.1 500     0.14 secs:      41 bytes ==> GET  /test.txt

我的节目输出：

 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate  memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)
 [ERROR] tcp_server.h:140 (function handle_client): Cannot allocate memory (error code: 12)

我的3个问题是：

什么没有分配内存？
为什么没有分配内存？
如何正确分配内存？

感谢您的帮助。请随时询问澄清或信息。

Answer 1

好的，所以我设法确定问题发生的位置。每个人的建议和评论都帮助我改进了我的代码，并进一步帮助解决了问题，所以我感谢你。这个问题在我写的另一个函数中排成一行，我在其中分配了一个长{{1}}的数组！这显然不是很节省内存。

所以，再一次，我想感谢您的意见和建议！

从C中的套接字读取时出现内存不足错误？

1 个答案: