如何编写一个多进程性能测试程序

在工作中经常碰到需要写一些多进程/多线程的测试程序，用来测试接口的性能。本文将会从零开始一点点增加代码，最终完成一个简易的多进程测试程序编写。该程序支持实时打印测试进结果和最终测试结果的统计。

同时，本文还涵盖了以下知识点，可以作为学习参考：

• 使用getopt_long()处理命令行选项和参数
• 使用fork()和wait()处理多进程
• 使用sigaction()配合alarm()处理定时信号SIGALRM
• 使用shmget()、shmat()、shmdt()、shmctl()等通过共享内存进行进程间通信
• 使用sigaction()捕获SIGINT和SIGQUIT信号，在程序终止前做共享内存清理工作

本文源码已开源Github

选项和参数的处理

为了使测试程序更高的可用性，我们getopt来处理选项和参数。

#include <stdio.h>      // printf
#include <getopt.h>     // getopt_long
#include <stdlib.h>     // strtol, abort
#include <limits.h>     // LONG_MIN, LONG_MAX

void ShowHelpInfo(char *name) {
    printf("Usage: %s [options]\n\n", name);
    printf("  Options:\n");
    printf("    -p/--proc         Number of processes (default: 1)\n");
    printf("    -d/--duration     Duration of test (unit: s, default: 10)\n");
    printf("    -h/--help         Show the help info\n");
    printf("\n");
    printf("  Example:\n");
    printf("    %s -p 4 -d 30\n", name);
    printf("\n");
}

int main(int argc, char *argv[]) {
    int c = 0;
    int option_index = 0;
    long procs = 1;
    long duration = 10;

    /**
     *  定义命令行参数列表，option结构的含义如下（详见 man 3 getopt）：
     *  struct option {
     *      const char *name;       // 参数的完整名称，对应命令中的 --xxx
     *      int  has_arg;           // 该参数是否带有一个值，如 –-config xxx.conf
     *      int *flag;              // 一般设置为NULL
     *      int  val;               // 解析到该参数后getopt_long函数的返回值，
     *                      // 为了方便维护，一般对应getopt_long调用时第三个参数
     *  };
     */
    static struct option arg_options[] =
    {
        {"proc", 1, NULL, 'p'},
        {"duration", 1, NULL, 'd'},
        {"help", 0, NULL, 'h'},
        {NULL, 0, NULL, 0}
    };

    /**
     *  注意：传递给getopt_long的第三个参数对应了命令行参数的缩写形式，如-h等，
     *  如果字符后面带有冒号":"，则说明该参数后跟一个值，如-c xxxxxx
     *  如果开头有冒号":"，则当一个选项缺少参数时，返回":"，否则，返回"?"
     */
    while ((c = getopt_long(argc, argv, ":p:d:h", arg_options, &option_index)
            ) != -1) {
        switch (c) {
        case 'h':
            ShowHelpInfo(argv[0]);
            //fprintf(stdout,"option is -%c, optarv is %s\n", c, optarg);
            return 0;
        case 'p':
            procs = strtol(optarg, NULL, 0);
            if (procs == LONG_MIN || procs == LONG_MAX) {
                fprintf(stderr, "The number of processes (%s) is overflow\n\n",
                        optarg);
                ShowHelpInfo(argv[0]);
                return -1;
            }
            else if (procs <= 0) {
                fprintf(stderr, "The number of processes must be > 0\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case 'd':
            duration = strtol(optarg, NULL, 0);
            if (duration == LONG_MIN || duration == LONG_MAX) {
                fprintf(stderr, "The duration of test (%s) is overflow\n\n",
                        optarg);
                ShowHelpInfo(argv[0]);
                return -1;
            }
            else if (procs <= 0) {
                fprintf(stderr, "The duration of test must be > 0\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case '?':
            fprintf (stderr, "Unknown option -%c\n\n", optopt);
            ShowHelpInfo(argv[0]);
            return -1;
        case ':':
           fprintf (stderr, "Option -%c requires an argument\n\n", optopt);
           ShowHelpInfo(argv[0]);
           return -1;
        default:
            abort();
        }
    }
    printf("processes:  %ld\n", procs);
    printf("duration:   %lds\n", duration);
    printf("\n-----------------------------Start Testing----------------------"
           "--------\n\n");

    printf("Hello world\n");
    return 0;

注意：传递给getopt_long的第三个参数对应了命令行参数的缩写形式，如-h, -v, -c等。

如果字符后面带有冒号”:”，则说明该参数后跟一个值，如-c xxxxxx

如果开头有冒号”:”，则当一个选项缺少参数时，返回”:”，否则，返回”?”

效果如下：

^_^$ make
gcc "-g" -c multi-process.c -o multi-process.o
gcc  -o test multi-process.o

^_^$ ./test
processes:  1
duration:   10s

-----------------------------Start Testing------------------------------

Hello world

选项或参数错误时：

^_^$ ./test -p
Option -p requires an argument

Usage: ./test [options]

  Options:
    -p/--proc         Number of processes (default: 1)
    -d/--duration     Duration of test (unit: s, default: 10)
    -h/--help         Show the help info

  Example:
    ./test -p 4 -d 30

增加多进程的支持

主进程fork出n个子进程后wait子进程，子进程则通过sigaction和alarm设置一个定时器，然后进行业务测试。

为了简洁，已经把选项参数处理的部分独立出去了。

#include <stdio.h>      // printf, fprintf
#include <sys/wait.h>   // wait
#include <sys/types.h>  // getpid, wait
#include <signal.h>     // sigaction, SIGLARM
#include <limits.h>     // LONG_MIN, LONG_MAX, ULLONG_MAX
#include <unistd.h>     // getpid
#include <string.h>     // memset
#include "multi-process.h"

int isStop = 0;             // 用于标记测试终止

typedef struct param_st {   // 自定义测试参数
    long index;
} Param;

void handle_signal_child(int sigNum)
{
    if (sigNum == SIGALRM) {
        isStop = 1;
    }
}

/* 实际业务测试函数 */
void doTest(void *param) {
    unsigned long long i = 0;
    Param *pa = (Param *)param;
    for(; i < ULLONG_MAX && !isStop; ++i) {
        /* DO YOUR WORK */
        /* DO YOUR WORK */
    }
    printf("process [pid = %6u] result: %llu\n", getpid(), i);
}

int main(int argc, char *argv[]) {
    int rv = 0;
    long i = 0;
    int proc_index = 0;
    Options opt;
    int isParent = 1;
    int wstatus = 0;
    pid_t pid = 0;
    struct sigaction act_child;

    rv = process_options(argc, argv, &opt);
    if (rv) {
        return -1;
    }

    printf("\n-----------------------------Start Testing----------------------"
           "--------\n\n");


    /* COMMON INIT */
    /* COMMON INIT */
    
    while(isParent && i < opt.procs) {
        pid =  fork();
        if(pid == -1) {         /* error */
            fprintf(stderr, "fork failed %d\n", pid);
            return -1;
        }
        else if(pid == 0) {     /* child */
            isParent = 0;
            proc_index = i;     // 记录进程索引
        }
        else {                  /* parent */
        }
        ++i;
    }
    if(isParent) {
        /* PARENT INIT */
        /* PARENT INIT */
        for(i =0 ; i < opt.procs; ++i) {
            pid = wait(&wstatus);                       // 等待子进程结束
            printf("process [pid = %6d] exit\n", pid);
        }
    }
    else {
        /* CHILD INIT */
        Param param;
        memset(&param, 0, sizeof(Param));
        param.index = proc_index;
        /* CHILD INIT */

        act_child.sa_handler = handle_signal_child;
        sigemptyset(&act_child.sa_mask);
        act_child.sa_flags = SA_RESETHAND;
        /* 用于测试时间到时，通知子进程结束测试 */
        rv = sigaction(SIGALRM, &act_child, NULL);
        if (rv) {
            fprintf(stderr, "sigaction() failed\n");
            return -1;
        }
        //signal(SIGALRM, handle_signal_child);
        alarm(opt.duration);                            // 设置测试时长
        doTest(&param);
        return 0;       /* child finished work */
    }

    printf("Hello World!\n");
    return 0;
}

效果如下：

^_^$ ./test -p 4 -d 2
processes:  4
duration:   2s

-----------------------------Start Testing------------------------------

process [pid =  11942] result: 446930553
process [pid =  11942] exit
process [pid =  11939] result: 434385097
process [pid =  11939] exit
process [pid =  11940] result: 442246977
process [pid =  11940] exit
process [pid =  11941] result: 442418811
process [pid =  11941] exit

这样已经可以实现简单的多进程测试，简单起见，示例代码里只是简单地进行了计数操作。读者如果想要进行自己特定的测试，只要在Param中增加需要的测试参数，接着在/* CHILD INIT */处进行参数初始化，然后在/* DO YOUR WORK */处添加实际的测试逻辑即可。

增加实时的结果统计及最终的结果汇总

为了使测试程序更加人性化，使其可以实时统计测试结果，结束时自动计算总的结果。这就需要引入父子进程间通信，我们选用共享内存的方式来实现。为了避免进程间同步对测试带来的影响，在共享内存中为每个子进程开辟了一个空间，每个子进程根据索引在自己的空间里写数据，由父进程进行结果的汇总。

#include <stdio.h>      // printf, fprintf
#include <sys/wait.h>   // wait
#include <sys/types.h>  // getpid, wait
#include <sys/ipc.h>    // shmget, shmat, shmctl, shmdt
#include <sys/shm.h>    // shmget, shmat, shmctl, shmdt
#include <signal.h>     // sigaction, SIGLARM
#include <limits.h>     // LONG_MIN, LONG_MAX, ULLONG_MAX
#include <errno.h>      // errno
#include <unistd.h>     // getpid
#include <string.h>     // memset
#include "multi-process.h"

typedef struct param_st {   // 自定义测试参数
    long index;
} Param;

typedef struct result_st {   // 自定义测试结果
    unsigned long long count;
} Result;

int isStop = 0;             // 用于标记测试终止
Options opt;                // 命令行选项
int shmid;                  // 共享内存id
Result *shm = NULL;         // 共享内存地址，用于存放测试结果
Result res_total;
Result res_last;

void handle_signal_child(int sigNum)
{
    if (sigNum == SIGALRM) {
        isStop = 1;
    }
}

void handle_signal_parent(int sigNum)
{
    if (sigNum == SIGALRM) {
        /* DO REAL-TIME STATISTICS */
        memset(&res_total, 0, sizeof(Result));
        for (long i = 0; i < opt.procs; ++i) {
            res_total.count += shm[i].count;
        }
        fprintf(stderr, "total count %12llu,  average %12.0lf/s\n",
                res_total.count, (res_total.count - res_last.count)
                / (double)opt.interval);
        memcpy(&res_last, &res_total, sizeof(Result));
        /* DO REAL-TIME STATISTICS */
        alarm(opt.interval);
    }
}

/* 实际业务测试函数 */
void doTest(void *param) {
    unsigned long long i = 0;
    Param *pa = (Param *)param;
    for (; i < ULLONG_MAX && !isStop; ++i) {
        /* DO YOUR WORK */
        ++shm[pa->index].count;
        /* DO YOUR WORK */
    }
}

int main(int argc, char *argv[]) {
    int rv = 0;
    long i = 0;
    int proc_index = 0;
    int isParent = 1;
    int wstatus = 0;
    pid_t pid = 0;
    struct sigaction act_child;
    struct sigaction act_parent;

    rv = process_options(argc, argv, &opt);
    if (rv) {
        return -1;
    }

    fprintf(stderr, "\n-----------------------------Start Testing-------------"
            "-----------------\n\n");


    /* COMMON INIT */
    shmid = shmget(IPC_PRIVATE, sizeof(sizeof(Result) * opt.procs), 0666);
    if (-1 == shmid) {
        fprintf(stderr, "shmget() failed\n");
        return -1;
    }
    fprintf(stderr, "shmid = %d\n", shmid);
    shm = (Result*)shmat(shmid, 0, 0);
    if ((void *) -1 == shm) {
        fprintf(stderr, "shmat() failed\n");
        return -1;
    }
    memset(shm, 0, sizeof(sizeof(Result) * opt.procs));
    /* COMMON INIT */

    while(isParent && i < opt.procs) {
        pid =  fork();
        if(pid == -1) {         /* error */
            fprintf(stderr, "fork failed %d\n", pid);
            return -1;
        }
        else if(pid == 0) {     /* child */
            isParent = 0;
            proc_index = i;     // 记录进程索引
        }
        else {                  /* parent */
        }
        ++i;
    }
    if(isParent) {
        /* PARENT INIT */
        memset(&act_parent, 0, sizeof(act_parent));
        act_parent.sa_handler = handle_signal_parent;
        /* 使wait被中断时可以自动恢复 */
        act_parent.sa_flags = SA_RESTART;
        rv = sigaction(SIGALRM, &act_parent, NULL);     // 用于定时统计结果
        //signal(SIGALRM, handle_signal_parent);
        if (rv) {
            fprintf(stderr, "sigaction() failed\n");
            return -1;
        }
        memset(&res_last, 0, sizeof(Result));
        alarm(opt.interval);
        /* PARENT INIT */
        /* DO FINAL STATISTICS */
        Result final;
        memset(&final, 0, sizeof(Result));
        for(i =0 ; i < opt.procs; ++i) {
            pid = wait(&wstatus);                       // 等待子进程结束
            alarm(0);                                   // 终止定时器
            if(pid == -1) {
                fprintf(stderr, "wait() failed, errno=%d\n", errno);
                return -1;
            }
            fprintf(stderr, "process [pid = %6d] exit\n", pid);
            fprintf(stderr, "process [pid = %6u] count %12llu in %lus,  "
                    "average %12.0lf/s\n", pid, shm[i].count, opt.duration, 
                    shm[i].count / (double)opt.duration);
            final.count += shm[i].count;
        }
        fprintf(stderr, "total count %12llu in %lus,  average %12.0lf/s\n",
               final.count, opt.duration, final.count / (double)opt.duration);
        /* DO FINAL STATISTICS */
        shmdt((void*)shm);
        /* 子进程退出之后自动detach了, 所以这里不需要通过IPC_STAT进行判断 */
        shmctl(shmid, IPC_RMID, 0);
    }
    else {
        /* CHILD INIT */
        Param param;
        memset(&param, 0, sizeof(Param));
        param.index = proc_index;
        /* CHILD INIT */

        act_child.sa_handler = handle_signal_child;
        sigemptyset(&act_child.sa_mask);
        //sigaddset(&act_child.sa_mask, SIGQUIT);
        //sigaddset(&act_child.sa_mask, SIGTERM);
        act_child.sa_flags = SA_RESETHAND;
        /* 用于测试时间到时，通知子进程结束测试 */
        rv = sigaction(SIGALRM, &act_child, NULL);
        if (rv) {
            fprintf(stderr, "sigaction() failed\n");
            return -1;
        }
        //signal(SIGALRM, handle_signal_child);
        alarm(opt.duration);                            // 设置测试时长
        doTest(&param);
        return 0;       /* child finished work */
    }

    return 0;
}

测试效果如下：

^_^$ ./test -p 4 -d 8 -i 1
processes:  4
duration:   8s
interval:   1s

-----------------------------Start Testing------------------------------

shmid = 2654220
total count    344235932,  average    344235932/s
total count    679573681,  average    335337749/s
total count   1026283924,  average    346710243/s
total count   1368302354,  average    342018430/s
total count   1708471662,  average    340169308/s
total count   2057211138,  average    348739476/s
total count   2398403059,  average    341191921/s
process [pid =  25124] exit
process [pid =  25124] count    688504473 in 8s,  average     86063059/s
process [pid =  25123] exit
process [pid =  25123] count    682379115 in 8s,  average     85297389/s
process [pid =  25125] exit
process [pid =  25125] count    682467102 in 8s,  average     85308388/s
process [pid =  25126] exit
process [pid =  25126] count    688159459 in 8s,  average     86019932/s
total count   2741510149 in 8s,  average    342688769/s

这里需要特别提一下wait()和sigaction()系统调用，默认情况下wait()会阻塞直到有任意一个子进程改变了其状态，或者有一个信号处理函数中断了wait()调用。所以我们程序中的wait()调用就会被自己的SIGALRM信号中断，返回-1同时errno为EINTR。这样我们就需要在wait()外面加一层循环来处理wait()被信号中断的情况。

通过在sigaction()时增加SA_RESTART标志，被中断的系统调用可以自动重开，也就省去了那个外层循环。另外，signal()封装了sigaction()，它里面默认就是设置了SA_RESTART，不过除非你有确切的理由，不然不建议使用signal()了。

增加SIGINT和SIGQUIT信号捕获

截止目前，我们已经完成了多进程的测试及结果统计。但其实还有一个潜在的问题，在实际测试中，我们经常会在测试还没完成时就手动^C终止程序执行。这样我们在程序中申请的共享内存就会得不到释放，造成内存泄漏。所以需要增加对SIGINT和SIGQUIT信号的处理函数，在里面做清理工作，释放共享内存。

如果已经不小心造成了共享内存的泄漏，可以通过如下命令手动进行删除。ipcrm shm <id>，如果是显式指定key的话也可以通过ipcrm -M <key>来进行删除。

今天，突然想到了，其实有一种更加简单的方法，即在shmat()之后立即进行shmctl(shmid, IPC_RMID, 0);。这样不仅简单，而且中间的空窗期也更短，cool！这样我们再也不用担心，^C造成内存泄漏了哈。

@@ -88,12 +88,14 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "shmget() failed\n");
         return -1;
     }
     fprintf(stderr, "shmid = %d\n", shmid);
     shm = (Result*)shmat(shmid, 0, 0);
     if ((void *) -1 == shm) {
         fprintf(stderr, "shmat() failed\n");
         return -1;
     }
+    /* 这里直接进行IPC_RMID操作，进程退出后会自动detach了, 从而释放共享内存 */
+    shmctl(shmid, IPC_RMID, 0);
     memset(shm, 0, sizeof(sizeof(Result) * opt.procs));
     /* COMMON INIT */

@@ -156,10 +135,6 @@ int main(int argc, char *argv[]) {
         fprintf(stderr, "total count %12llu in %lus,  average %12.0lf/s\n",
                final.count, opt.duration, final.count / (double)opt.duration);
         /* DO FINAL STATISTICS */
-
-        shmdt((void*)shm);
-        /* 子进程退出之后自动detach了, 所以这里不需要通过IPC_STAT进行判断 */
-        shmctl(shmid, IPC_RMID, 0);
     }
     else {
         /* CHILD INIT */

封装错误判断函数

为了使代码看起来更加简洁，避免每个函数调用后面跟着一个if(){}判断块，我们对错误判断及日志打印函数进行了一个简单的封装。封装的函数如下：

其中mylog()单纯打印日志，fail()打印日志后退出进程，fail_if()先判断条件，如果成立打印日志退出，fail_clean_if()也是先判断条件，条件成立则打印日志，执行传入的清理函数。然后退出进程。

#include "common.h"

#include <stdio.h>      // stderr
#include <stdarg.h>     // va_start, vfprintf, va_end
#include <stdlib.h>     // exit

void fail_if(bool condition, const char *fmt, ...) {
    if (condition) {
        va_list args;
        va_start(args, fmt);
        vfprintf(stderr, fmt, args);
        va_end(args);
        exit(1);
    }
}

void fail(const char *fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
    exit(1);
}

void mylog(const char *fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
}

void fail_clean_if(bool condition, cleanup clean, void *param, const char *fmt, ...) {
    if (condition) {
        va_list args;
        va_start(args, fmt);
        vfprintf(stderr, fmt, args);
        va_end(args);
        clean(param);
        exit(1);
    }
}

添加实际测试用例

接下来我们来添加实际有意义的测试用例，这里以OpenSSL引擎的性能测试为例来进行说明。为了我们的代码更清晰，已经将具体测试相关的代码独立为一个源文件。common.c封装错误函数，opt.c处理命令行选项，work.c处理具体测试，multi-process.c则负责测试的主控。完整的代码如下：

• common.h

#ifndef HEADER_COMMON_H
#define HEADER_COMMON_H
#include <stdbool.h>    // bool, true, false

typedef void (*cleanup) (void *);
void fail_if(bool condition, const char *fmt, ...);
void fail(const char *fmt, ...);
void mylog(const char *fmt, ...);
void fail_clean_if(bool condition, cleanup clean, void *param, const char *fmt, ...);


#endif /* HEADER_COMMON_H */

• common.c

#include "common.h"

#include <stdio.h>      // stderr
#include <stdarg.h>     // va_start, vfprintf, va_end
#include <stdlib.h>     // exit

void fail_if(bool condition, const char *fmt, ...) {
    if (condition) {
        va_list args;
        va_start(args, fmt);
        vfprintf(stderr, fmt, args);
        va_end(args);
        exit(1);
    }
}

void fail(const char *fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
    exit(1);
}

void mylog(const char *fmt, ...) {
    va_list args;
    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);
}

void fail_clean_if(bool condition, cleanup clean, void *param, const char *fmt, ...) {
    if (condition) {
        va_list args;
        va_start(args, fmt);
        vfprintf(stderr, fmt, args);
        va_end(args);
        clean(param);
        exit(1);
    }
}

• opt.h

#ifndef HEADER_OPT_H
#define HEADER_OPT_H

typedef enum test{
    hash, sign, verify, enc, dec
} Test;

typedef struct options_st {
    long procs;                 // 进程数
    long duration;              // 测试时间
    long interval;              // 统计间隔
    Test test;                  // 测试类型
    long len;                   // 摘要原文长度
    const char *key;            // 密钥文件路径
    const char *cert;           // 证书文件路径
    const char *loglevel;       // 日志等级
} Options;

/* 处理参数 */
int process_options(int argc, char *argv[], Options *opt);

#endif /* HEADER_OPT_H */

• opt.c

#include "opt.h"

#include <limits.h>     // LONG_MIN, LONG_MAX, ULLONG_MAX
#include <string.h>     // memset
#include <stdlib.h>     // strtol, abort
#include <getopt.h>     // geropt_long

#include "common.h"     // mylog

static void ShowHelpInfo(char *name) {
    mylog("Usage: %s [options]\n\n", name);
    mylog("  Options:\n");
    mylog("    -p/--proc         Number of processes (default: 1)\n");
    mylog("    -d/--duration     Duration of test (unit: s, default: 10)\n");
    mylog("    -i/--interval     Interval of statisics (unit: s, default: 1)\n");
    mylog("    -t/--test         Test case (hash|sign|verify|enc|dec, default: hash)\n");
    mylog("    -l/--len          Hash data len (unit: byte, default: 1024)\n");
    mylog("    -k/--key          PEM Key file path (default: ./key.pem)\n");
    mylog("    -c/--cert         PEM Cert file path (default: ./cert.pem)\n");
    mylog("    -o/--loglevel     Engine log level (0-9, default: 0)\n");
    mylog("    -h/--help         Show the help info\n");
    mylog("\n");
    mylog("  Example:\n");
    mylog("    %s -p 1 -d 30 -i 1 -t sign -k key.pem -c cert.pem\n", name);
    mylog("\n");
}

/* 处理参数 */
int process_options(int argc, char *argv[], Options *opt) {
    int c = 0;
    int option_index = 0;
    long procs = 1;
    long duration = 10;
    long interval = 1;
    Test test = hash;
    long len = 1024;
    const char *key = "./key.pem";
    const char *cert = "./cert.pem";
    const char *loglevel = "0";
    /**
     *  定义命令行参数列表，option结构的含义如下（详见 man 3 getopt）：
     *  struct option {
     *      const char *name;       // 参数的完整名称，对应命令中的 --xxx
     *      int  has_arg;           // 该参数是否带有一个值，如 –config xxx.conf
     *      int *flag;              // 一般设置为NULL
     *      int  val;               // 解析到该参数后getopt_long函数的返回值，
     *                      // 为了方便维护，一般对应getopt_long调用时第三个参数
     *  };
     */
    static struct option arg_options[] =
    {
        {"proc", 1, NULL, 'p'},
        {"duration", 1, NULL, 'd'},
        {"interval", 1, NULL, 'i'},
        {"test", 1, NULL, 't'},
        {"len", 1, NULL, 'l'},
        {"key", 1, NULL, 'k'},
        {"cert", 1, NULL, 'c'},
        {"log", 1, NULL, 'g'},
        {"help", 0, NULL, 'h'},
        {NULL, 0, NULL, 0}
    };

    /**
     *  注意：传递给getopt_long的第三个参数对应了命令行参数的缩写形式，如-h等，
     *  如果字符后面带有冒号":"，则说明该参数后跟一个值，如-c xxxxxx
     *  如果开头有冒号":"，则当一个选项缺少参数时，返回":"，否则，返回"?"
     */
    while ((c = getopt_long(argc, argv, ":p:d:i:t:l:k:c:g:h", arg_options, &option_index)
            ) != -1) {
        switch (c) {
        case 'h':
            ShowHelpInfo(argv[0]);
            //fprintf(stderr,"option is -%c, optarv is %s\n", c, optarg);
            exit(0);
        case 'p':
            procs = strtol(optarg, NULL, 0);
            if (procs == LONG_MIN || procs == LONG_MAX) {
                mylog("The number of processes (%s) is overflow\n\n", optarg);
                ShowHelpInfo(argv[0]);
                return -1;
            }
            else if (procs <= 0) {
                mylog("The number of processes must be > 0\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case 'd':
            duration = strtol(optarg, NULL, 0);
            if (duration == LONG_MIN || duration == LONG_MAX) {
                mylog("The duration of test (%s) is overflow\n\n", optarg);
                ShowHelpInfo(argv[0]);
                return -1;
            }
            else if (duration <= 0) {
                mylog("The duration of test must be > 0\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case 'i':
            interval = strtol(optarg, NULL, 0);
            if (interval == LONG_MIN || interval == LONG_MAX) {
                mylog("The interval of statistics (%s) is overflow\n\n",
                      optarg);
                ShowHelpInfo(argv[0]);
                return -1;
            }
            else if (interval <= 0) {
                mylog("The interval of statistics must be > 0\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case 't':
            if(!strcasecmp("hash", optarg)) {
                test = hash;
            }
            else if(!strcasecmp("sign", optarg)) {
                test = sign;
            }
            else if(!strcasecmp("verify", optarg)) {
                test = verify;
            }
            else if(!strcasecmp("enc", optarg)) {
                test = enc;
            }
            else if(!strcasecmp("dec", optarg)) {
                test = dec;
            }
            else {
                mylog("Unknown test case type\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case 'l':
            len = strtol(optarg, NULL, 0);
            if (len == LONG_MIN || len == LONG_MAX) {
                mylog("The len of hash data (%s) is overflow\n\n",
                      optarg);
                ShowHelpInfo(argv[0]);
                return -1;
            }
            else if (len <= 0) {
                mylog("The len of hash data must be > 0\n\n");
                ShowHelpInfo(argv[0]);
                return -1;
            }
            break;
        case 'k':
            key = optarg;
            break;
        case 'c':
            cert = optarg;
            break;
        case 'g':
            loglevel = optarg;
            break;
        case '?':
            mylog("Unknown option -%c\n\n", optopt);
            ShowHelpInfo(argv[0]);
            return -1;
        case ':':
            mylog("Option -%c requires an argument\n\n", optopt);
            ShowHelpInfo(argv[0]);
            return -1;
        default:
            exit(1);
        }
    }
    mylog("processes:  %ld\n", procs);
    mylog("duration:   %lds\n", duration);
    mylog("interval:   %lds\n", interval);
    mylog("test:       #%d\n", test);
    mylog("len:        %ld bytes\n", len);
    mylog("key:        %s\n", key);
    mylog("cert:       %s\n", cert);
    mylog("loglevel:   %s\n", loglevel);
    memset(opt, 0, sizeof(Options));
    opt->procs = procs;
    opt->duration = duration;
    opt->interval = interval;
    opt->test = test;
    opt->len = len;
    opt->key = key;
    opt->cert = cert;
    opt->loglevel = loglevel;

    return 0;
}

• work.h

#ifndef HEADER_WORK_H
#define HEADER_WORK_H
#include <openssl/evp.h>
#include <openssl/bio.h>
#include "opt.h"

/* 自定义测试参数 */
typedef struct hash_param_st {
    long index;
    unsigned char *data;
    unsigned int data_len;
    unsigned char md[128];
    unsigned int md_len;
    EVP_MD_CTX *ctx;
} HashParam;

typedef struct sign_param_st {
    long index;
    unsigned char data[48];
    size_t data_len;
    unsigned char sig[256];
    size_t sig_len;
    EVP_PKEY_CTX *ctx;
    BIO *in;
} SignParam;

typedef SignParam VerifyParam;

typedef struct enc_param_st {
    long index;
    unsigned char data[48];
    size_t data_len;
    unsigned char enc[256];
    size_t enc_len;
    EVP_PKEY_CTX *ctx;
    BIO *in;
} EncParam;

typedef EncParam DecParam;

/* 自定义测试结果 */
typedef struct result_st {
    unsigned long long count;
} Result;

typedef void (*init_fn) (Options *opt, void **param, long proc_index);
typedef void (*work_fn) (void *param);
typedef void (*clean_fn) (void *param);

extern init_fn test_init;
extern work_fn test_work;
extern clean_fn test_clean;

void global_init(Options *opt);

void global_clean();

#endif /* HEADER_WORK_H */

• work.c

#include "work.h"
#include <string.h>
#include <openssl/engine.h>
#include <openssl/pem.h>
#include "common.h"

const char* so_path = "/usr/local/ssl/lib/myengine.so";

init_fn test_init = NULL;
work_fn test_work = NULL;
clean_fn test_clean = NULL;

static void hash_init(Options *opt, void **param, long proc_index);
static void hash_work(void *param);
static void hash_clean(void *param);
static void sign_init(Options *opt, void **param, long proc_index);
static void sign_work(void *param);
static void sign_clean(void *param);
static void verify_init(Options *opt, void **param, long proc_index);
static void verify_work(void *param);
static void verify_clean(void *param);
static void encrypt_init(Options *opt, void **param, long proc_index);
static void encrypt_work(void *param);
static void encrypt_clean(void *param);
static void decrypt_init(Options *opt, void **param, long proc_index);
static void decrypt_work(void *param);
static void decrypt_clean(void *param);


void global_init(Options *opt) {
    ENGINE *e = NULL;
    if (opt->test == hash) {
        test_init = hash_init;
        test_work = hash_work;
        test_clean = hash_clean;
    }
    else if (opt->test == sign) {
        test_init = sign_init;
        test_work = sign_work;
        test_clean = sign_clean;
    }
    else if (opt->test == verify) {
        test_init = verify_init;
        test_work = verify_work;
        test_clean = verify_clean;
    }
    else if (opt->test == enc) {
        test_init = encrypt_init;
        test_work = encrypt_work;
        test_clean = encrypt_clean;
    }
    else if (opt->test == dec) {
        test_init = decrypt_init;
        test_work = decrypt_work;
        test_clean = decrypt_clean;
    }
    OpenSSL_add_all_algorithms();
    /* ENGINE INIT */
    ENGINE_load_dynamic();
    if (!(e = ENGINE_by_id("dynamic"))) {
        fail("ENGINE_by_id(\"dynamic\") fail\n");
    }
    if (!ENGINE_ctrl_cmd_string(e, "SO_PATH", so_path, 0)) {
        fail("ENGINE_ctrl_cmd_string(\"SO_PATH\") fail, so_path = %s\n", 
             so_path);
    }
    if (!ENGINE_ctrl_cmd_string(e, "LIST_ADD", "1", 0)) {
        fail("ENGINE_ctrl_cmd_string(\"LIST_ADD\") fail\n");
    }
    if (!ENGINE_ctrl_cmd_string(e, "LOAD", NULL, 0)) {
        fail("ENGINE_ctrl_cmd_string(\"LOAD\") fail\n");
    }
    if (!ENGINE_init(e)) {
        fail("ENGINE_init() fail\n");
    }
    if (!ENGINE_ctrl_cmd_string( e, "ENGINE_SET_LOGLEVEL", opt->loglevel, 0)) {
        fail("ENGINE_ctrl_cmd_string(\"ENGINE_SET_LOGLEVEL\") fail\n");
    }
    if (!ENGINE_set_default(e, ENGINE_METHOD_ALL)) {
        fail("ENGINE_set_default() fail\n");
    }
    ENGINE_free(e);
    /* ENGINE INIT */
}

void global_clean() {
    EVP_cleanup();
}

static void hash_init(Options *opt, void **param, long proc_index) {
    HashParam *p;
    p = OPENSSL_malloc(sizeof(HashParam));
    fail_if(!p, "OPENSSL_malloc() fail\n");
    memset(p, 0, sizeof(HashParam));

    p->ctx = EVP_MD_CTX_create();
    fail_clean_if(!p->ctx, hash_clean, (void *)p, "EVP_MD_CTX_create() fail\n");
    EVP_MD_CTX_init(p->ctx);

    p->data = OPENSSL_malloc(opt->len);
    fail_clean_if(!p->data, hash_clean, (void *)p, "OPENSSL_malloc() fail\n");
    fail_clean_if(RAND_bytes(p->data, sizeof(opt->len)) <= 0, hash_clean, (void *)p,
                  "RAND_bytes() fail\n");
    p->data_len = opt->len;

    p->index = proc_index;

    *param = p;
}

static void hash_work(void *param) {
    HashParam *p = (HashParam *)param;
    const EVP_MD *md = EVP_get_digestbyname("SHASH");
    fail_clean_if(!md, hash_clean, param, 
                  "EVP_get_digestbyname(\"SHASH\") fail\n");
    fail_clean_if(!EVP_DigestInit_ex(p->ctx, md, NULL), 
                  hash_clean, param, "EVP_DigestInit_ex() fail\n");
    fail_clean_if(!EVP_DigestUpdate(p->ctx, p->data, p->data_len),
                  hash_clean, param, "EVP_DigestUpdate() fail\n");
    fail_clean_if(!EVP_DigestFinal_ex(p->ctx, p->md, &p->md_len),
                  hash_clean, param, "EVP_DigestFinal_ex() fail\n");
}

static void hash_clean(void *param) {
    HashParam *p = (HashParam *)param;
    if (p->data)
        OPENSSL_free(p->data);
    if (p->ctx)
        EVP_MD_CTX_destroy(p->ctx);
    OPENSSL_free(p);
}

static void sign_init(Options *opt, void **param, long proc_index) {
    SignParam *p;
    EVP_PKEY *pkey;
    p = OPENSSL_malloc(sizeof(SignParam));
    fail_if(!p, "OPENSSL_malloc() fail\n");
    memset(p, 0, sizeof(SignParam));

    p->in = BIO_new_file(opt->key, "r");
    fail_clean_if(!p->in, sign_clean, (void *)p, 
                  "BIO_new_file(%s) fail\n", opt->key);
    pkey = PEM_read_bio_PrivateKey(p->in, NULL, NULL, NULL);
    fail_clean_if(!pkey, sign_clean, (void *)p, 
                  "PEM_read_bio_PrivateKey() fail\n");
    p->ctx = EVP_PKEY_CTX_new(pkey, NULL);
    if (!p->ctx) {
        EVP_PKEY_free(pkey);
        fail_clean_if(1, sign_clean, (void *)p, "EVP_PKEY_CTX_new() fail\n");
    }
    fail_clean_if(!EVP_PKEY_sign_init(p->ctx), sign_clean, (void *)p, 
                  "EVP_PKEY_sign_init() fail\n");

    fail_clean_if(RAND_bytes(p->data, sizeof(p->data)) <= 0, sign_clean, (void *)p,
                  "RAND_bytes() fail\n");
    p->data_len = sizeof(p->data);
    p->sig_len = sizeof(p->sig);

    p->index = proc_index;
    *param = p;
}

static void sign_work(void *param) {
    SignParam *p = (SignParam *)param;
    fail_clean_if(!EVP_PKEY_sign(p->ctx, p->sig, &p->sig_len, p->data, 
                                 p->data_len), sign_clean, param,
                  "EVP_PKEY_sign() fail\n");
}

static void sign_clean(void *param) {
    SignParam *p = (SignParam *)param;
    if (p->ctx)
        EVP_PKEY_CTX_free(p->ctx);
    if (p->in)
        BIO_free(p->in);
    OPENSSL_free(p);
}

static void verify_init(Options *opt, void **param, long proc_index) {
    VerifyParam *p;
    EVP_PKEY *pkey;
    X509 *x;
    unsigned char data[48];
    size_t data_len;
    unsigned char sig[256];
    size_t sig_len;
    /* 先签名一次，获取数据 */
    SignParam *sp;
    sign_init(opt, (void **)&sp, (long)0);
    sign_work(sp);
    memcpy(data, sp->data, sp->data_len);
    data_len = sp->data_len;
    memcpy(sig, sp->sig, sp->sig_len);
    sig_len = sp->sig_len;
    sign_clean(sp);

    p = OPENSSL_malloc(sizeof(VerifyParam));
    fail_if(!p, "OPENSSL_malloc() fail\n");
    memset(p, 0, sizeof(VerifyParam));
    
    p->in = BIO_new_file(opt->cert, "r");
    fail_clean_if(!p->in, verify_clean, (void *)p, 
                  "BIO_new_file(%s) fail\n", opt->cert);
    x = PEM_read_bio_X509(p->in, NULL, 0, NULL);
    fail_clean_if(!x, verify_clean, (void *)p, 
                  "PEM_read_bio_X509() fail\n");
    pkey = X509_get_pubkey(x);
    X509_free(x);
    fail_clean_if(!pkey, verify_clean, (void *)p, "X509_get_pubkey() fail\n");
    p->ctx = EVP_PKEY_CTX_new(pkey, NULL);
    if (!p->ctx) {
        EVP_PKEY_free(pkey);
        fail_clean_if(1, verify_clean, (void *)p, "EVP_PKEY_CTX_new() fail\n");
    }
    fail_clean_if(!EVP_PKEY_verify_init(p->ctx), verify_clean, (void *)p, 
                  "EVP_PKEY_verify_init() fail\n");

    memcpy(p->data, data, data_len);
    p->data_len = data_len;
    memcpy(p->sig, sig, sig_len);
    p->sig_len = sig_len;

    p->index = proc_index;
    *param = p;
}

static void verify_work(void *param) {
    VerifyParam *p = (VerifyParam *)param;
    fail_clean_if(!EVP_PKEY_verify(p->ctx, p->sig, p->sig_len, p->data, 
                                 p->data_len), verify_clean, param,
                  "EVP_PKEY_verify() fail\n");
}

static void verify_clean(void *param) {
    VerifyParam *p = (VerifyParam *)param;
    if (p->ctx)
        EVP_PKEY_CTX_free(p->ctx);
    if (p->in)
        BIO_free(p->in);
    OPENSSL_free(p);
}

static void encrypt_init(Options *opt, void **param, long proc_index) {
    EncParam *p;
    EVP_PKEY *pkey;
    X509 *x;
    p = OPENSSL_malloc(sizeof(EncParam));
    fail_if(!p, "OPENSSL_malloc() fail\n");
    memset(p, 0, sizeof(EncParam));

    p->in = BIO_new_file(opt->cert, "r");
    fail_clean_if(!p->in, encrypt_clean, (void *)p, 
                  "BIO_new_file(%s) fail\n", opt->cert);
    x = PEM_read_bio_X509(p->in, NULL, 0, NULL);
    fail_clean_if(!x, encrypt_clean, (void *)p, 
                  "PEM_read_bio_X509() fail\n");
    pkey = X509_get_pubkey(x);
    X509_free(x);
    fail_clean_if(!pkey, encrypt_clean, (void *)p, "X509_get_pubkey() fail\n");
    p->ctx = EVP_PKEY_CTX_new(pkey, NULL);
    if (!p->ctx) {
        EVP_PKEY_free(pkey);
        fail_clean_if(1, encrypt_clean, (void *)p, "EVP_PKEY_CTX_new() fail\n");
    }
    fail_clean_if(!EVP_PKEY_encrypt_init(p->ctx), encrypt_clean, (void *)p, 
                  "EVP_PKEY_encrypt_init() fail\n");

    fail_clean_if(RAND_bytes(p->data, sizeof(p->data)) <= 0, encrypt_clean, (void *)p,
                  "RAND_bytes() fail\n");
    p->data_len = sizeof(p->data);
    p->enc_len = sizeof(p->enc);

    p->index = proc_index;
    *param = p;
}

static void encrypt_work(void *param) {
    EncParam *p = (EncParam *)param;
    fail_clean_if(!EVP_PKEY_encrypt(p->ctx, p->enc, &p->enc_len, p->data, 
                                 p->data_len), encrypt_clean, param,
                  "EVP_PKEY_encrypt() fail\n");
}

static void encrypt_clean(void *param) {
    EncParam *p = (EncParam *)param;
    if (p->ctx)
        EVP_PKEY_CTX_free(p->ctx);
    if (p->in)
        BIO_free(p->in);
    OPENSSL_free(p);
}

static void decrypt_init(Options *opt, void **param, long proc_index) {
    DecParam *p;
    EVP_PKEY *pkey;
    unsigned char data[48];
    size_t data_len;
    unsigned char enc[256];
    size_t enc_len;
    /* 先加密一次，获取数据 */
    EncParam *ep;
    encrypt_init(opt, (void **)&ep, (long)0);
    encrypt_work(ep);
    memcpy(data, ep->data, ep->data_len);
    data_len = ep->data_len;
    memcpy(enc, ep->enc, ep->enc_len);
    enc_len = ep->enc_len;
    encrypt_clean(ep);

    p = OPENSSL_malloc(sizeof(DecParam));
    fail_if(!p, "OPENSSL_malloc() fail\n");
    memset(p, 0, sizeof(DecParam));
    
    p->in = BIO_new_file(opt->key, "r");
    fail_clean_if(!p->in, decrypt_clean, (void *)p, 
                  "BIO_new_file(%s) fail\n", opt->key);
    pkey = PEM_read_bio_PrivateKey(p->in, NULL, NULL, PEM_AUTO_KEYPASS);
    fail_clean_if(!pkey, decrypt_clean, (void *)p, 
                  "PEM_read_bio_PrivateKey() fail\n");
    p->ctx = EVP_PKEY_CTX_new(pkey, NULL);
    if (!p->ctx) {
        EVP_PKEY_free(pkey);
        fail_clean_if(1, decrypt_clean, (void *)p, "EVP_PKEY_CTX_new() fail\n");
    }
    fail_clean_if(!EVP_PKEY_decrypt_init(p->ctx), decrypt_clean, (void *)p, 
                  "EVP_PKEY_decrypt_init() fail\n");

    memcpy(p->data, data, data_len);
    p->data_len = data_len;
    memcpy(p->enc, enc, enc_len);
    p->enc_len = enc_len;

    p->index = proc_index;
    *param = p;
}

static void decrypt_work(void *param) {
    DecParam *p = (DecParam *)param;
    fail_clean_if(!EVP_PKEY_decrypt(p->ctx, p->data, &p->data_len, p->enc, 
                                 p->enc_len), decrypt_clean, param,
                  "EVP_PKEY_decrypt() fail\n");
}

static void decrypt_clean(void *param) {
    DecParam *p = (DecParam *)param;
    if (p->ctx)
        EVP_PKEY_CTX_free(p->ctx);
    if (p->in)
        BIO_free(p->in);
    OPENSSL_free(p);
}

• multi-process.c

#include <sys/wait.h>   // wait
#include <sys/types.h>  // getpid, wait
#include <sys/ipc.h>    // shmget, shmat, shmctl, shmdt
#include <sys/shm.h>    // shmget, shmat, shmctl, shmdt
#include <signal.h>     // sigaction, SIGLARM
#include <limits.h>     // LONG_MIN, LONG_MAX, ULLONG_MAX
#include <errno.h>      // errno
#include <unistd.h>     // getpid
#include <string.h>     // memset
#include "common.h"
#include "opt.h"
#include "work.h"

int isStop = 0;             // 用于标记测试终止
Options opt;                // 命令行选项
int shmid;                  // 共享内存id
Result *shm = NULL;         // 共享内存地址，用于存放测试结果
Result res_total;
Result res_last;

void handle_signal_child(int sigNum)
{
    if (sigNum == SIGALRM) {
        isStop = 1;
    }
}

void handle_signal_parent(int sigNum)
{
    if (sigNum == SIGALRM) {
        /* DO REAL-TIME STATISTICS */
        memset(&res_total, 0, sizeof(Result));
        long i = 0;
        for (; i < opt.procs; ++i) {
            res_total.count += shm[i].count;
        }
        mylog("total count %12llu,  average %12.0lf/s\n",
                res_total.count, (res_total.count - res_last.count)
                / (double)opt.interval);
        memcpy(&res_last, &res_total, sizeof(Result));
        /* DO REAL-TIME STATISTICS */
        alarm(opt.interval);
    }
}

/* 执行测试主循环函数 */
void doTest(void *param) {
    unsigned long long i = 0;
    HashParam *pa = (HashParam *)param;
    for (; i < ULLONG_MAX && !isStop; ++i) {
        /* DO YOUR WORK */
        test_work(param);
        ++shm[pa->index].count;
        /* DO YOUR WORK */
    }
}

int main(int argc, char *argv[]) {
    int rv = 0;
    long i = 0;
    int proc_index = 0;
    int isParent = 1;
    int wstatus = 0;
    pid_t pid = 0;
    struct sigaction act_child;
    struct sigaction act_parent;

    rv = process_options(argc, argv, &opt);
    if (rv) {
        return -1;
    }

    mylog("\n-----------------------------Start Testing-----------------------"
          "-------\n\n");


    /* COMMON INIT */
    shmid = shmget(IPC_PRIVATE, sizeof(sizeof(Result) * opt.procs), 0666);
    fail_if(-1 == shmid, "shmget() failed\n");
    mylog("shmid = %d\n", shmid);
    shm = (Result*)shmat(shmid, 0, 0);
    fail_if((void *) -1 == shm, "shmat() failed\n");

    /* 这里直接进行IPC_RMID操作，进程退出之后会自动detach了, 从而释放共享内存 */
    shmctl(shmid, IPC_RMID, 0);
    memset(shm, 0, sizeof(sizeof(Result) * opt.procs));

    global_init(&opt);
    /* COMMON INIT */

    while(isParent && i < opt.procs) {
        pid =  fork();
        fail_if(-1 == pid, "fork failed %d\n", pid);    /* error */
        if(pid == 0) {                                  /* child */
            isParent = 0;
            proc_index = i;                             // 记录进程索引
        }
        else {                                          /* parent */
        }
        ++i;
    }
    if(isParent) {
        /* PARENT INIT */
        memset(&act_parent, 0, sizeof(act_parent));
        act_parent.sa_handler = handle_signal_parent;
        /* 使wait被中断时可以自动恢复 */
        act_parent.sa_flags = SA_RESTART;
        rv = sigaction(SIGALRM, &act_parent, NULL);     // 用于定时统计结果
        fail_if(rv, "sigaction() failed\n");

        memset(&res_last, 0, sizeof(Result));
        alarm(opt.interval);
        /* PARENT INIT */

        /* DO FINAL STATISTICS */
        Result final;
        memset(&final, 0, sizeof(Result));
        for(i =0 ; i < opt.procs; ++i) {
            pid = wait(&wstatus);                       // 等待子进程结束
            alarm(0);                                   // 终止定时器
            fail_if(-1 == pid, "wait() failed, errno=%d\n", errno);
            mylog("process [pid = %6d] exit\n", pid);
            mylog("process [pid = %6u] count %12llu in %lus,"
                  "  average %12.0lf/s\n", pid, shm[i].count, opt.duration, 
                  shm[i].count / (double)opt.duration);
            final.count += shm[i].count;
        }
        mylog("total count %12llu in %lus,  average %12.0lf/s\n", 
               final.count, opt.duration, final.count / (double)opt.duration);
        /* DO FINAL STATISTICS */

        /* PARENT CLEANUP */
        global_clean();
        /* PARENT CLEANUP */
    }
    else {
        /* CHILD INIT */
        void *param;
        test_init(&opt, &param, proc_index);
        /* CHILD INIT */

        act_child.sa_handler = handle_signal_child;
        sigemptyset(&act_child.sa_mask);
        act_child.sa_flags = SA_RESETHAND;
        /* 用于测试时间到时，通知子进程结束测试 */
        rv = sigaction(SIGALRM, &act_child, NULL);
        fail_if(rv, "sigaction() failed\n");
        alarm(opt.duration);                            // 设置测试时长
        doTest(param);

        /* CHILD CLEANUP */
        test_clean(param);
        global_clean();
        /* CHILD CLEANUP */
        return 0;       /* child finished work */
    }

    return 0;
}

总结

至此，一个多进程的测试程序就算完成了。读者可以根据自身测试需要，按如下步骤修改以进行自定义的测试。

1. 在opt.c和opt.h中，添加需要的命令行选项
2. 在work.c和work.h中，global_init()和global_clean()内进行全局的初始化及全局的清理工作
3. 在work.c和work.h中，添加自定义的测试函数，以及相应的测试参数和测试结果
4. 主控multi-process.c通过test_init()、test_work()、test_clean()调用测试相关的初始化、执行及清理工作
5. 主控multi-process.c中，修改测试结果的更新与统计操作。

主控multi-process.c中：

• COMMON INIT、PARENT INIT和CHILD INIT代码块处分别进行公共的初始化工作和父子进程特定的初始化工作。
• PARENT CLEANUP和CHILD CLEANUP代码块处则分别进行对应的清理工作。
• DO YOUR WORK处执行具体的测试，DO REAL-TIME STATISTICS和DO FINAL STATISTICS处进行测试结果的统计。

当然本文还有一些不足之处，比如当前是用的OpenSSL1.0.2接口，没有兼容不同版本的OpenSSL。还有代码风格的问题，在函数命名和注释方式上不统一。但是考虑到这个是测试程序，就不计较这么多了（^。^）