php用root权限调用脚本 及由此引发的make时找不到系统头文件的问题

php用root权限调用脚本有两种方法：
①利用C来实现互换权限
②新建Apache的执行用户并赋予root权限
第二种方法的权限安全问题没有仔细研究所以没尝试，用了第一种方法，可行。
程序代码如下：
程序编译或者修改重新编译后，要执行 chmod u+s syncfile，“设置uid，当普通用户执行的时候是以root的权限来执行的，在run.c里面会交换进程的ID，从而利用root的ID为0，来执行”

#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>

int main(int argc, char **argv)
{
    printf("argc:%d\n",argc);
    if (argc!=3)
    {
        printf("Missing parameters!\n");
        return -1;
    }
    if (strcmp(argv[1],"php.py") &&
        strcmp(argv[1],"cpp.py") &&
        strcmp(argv[1],"frontend.py") &&
        strcmp(argv[1],"z.py"))
    {
        printf("parameters err!\n");
        return -1;
    }

    uid_t uid , euid ;
    uid = getuid();
    euid= geteuid();
    printf("my uid:%u\n",getuid());
    printf("my euid:%u\n",geteuid());
    if(setreuid(euid,uid))
        perror("setreuid");
    printf("after setreuid uid:%u\n",getuid());
    printf("after setreuid euid:%u\n",geteuid());
    char cmd[100] = {0};
    snprintf(cmd, sizeof(cmd), "python ./%s %s", argv[1], argv[2]);
    printf("%s \n", cmd);
    int iRet = system(cmd);
    return iRet;
}

需要注意的是，安全起见，对于传入的要执行的cmd要做限制，只允许做某些特定操作。


参考文章：
http://www.cnblogs.com/awinlei/archive/2013/04/02/2995367.html



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可以调用脚本之后，遇到另外一个问题，脚本里执行了make来编译c++程序，结果报一大堆错，主要的一些错误如下：

/usr/include/sys/types.h:147:20: error: stddef.h: No such file or directory
/usr/include/sched.h:30:20: error: stddef.h: No such file or directory
.//include/stdhd.h:12:20: error: stdarg.h: No such file or directory
.//include/stdhd.h:37:18: error: vector: No such file or directory
.//include/stdhd.h:38:18: error: string: No such file or directory
.//include/stdhd.h:39:15: error: map: No such file or directory
.//include/stdhd.h:40:15: error: set: No such file or directory
.//include/stdhd.h:41:16: error: list: No such file or directory
.//include/stdhd.h:42:20: error: iostream: No such file or directory
.//include/stdhd.h:43:17: error: queue: No such file or directory
.//include/stdhd.h:44:19: error: iomanip: No such file or directory
/usr/include/mysql/mysql_com.h:408: error: 'size_t' has not been declared
/usr/include/mysql/mysql_com.h:410: error: 'size_t' has not been declared
/usr/include/mysql/mysql_com.h:412: error: 'size_t' has not been declared
/usr/include/mysql/mysql_com.h:413: error: 'size_t' has not been declared
/usr/include/mysql/mysql_com.h:414: error: 'size_t' has not been declared
……

类似的报错非常多，怀疑make的时候没有找到系统头文件导致的。

想起来以前在脚本里执行oracle查询语句，由于缺少oracle环境变量导致执行失败的例子。
在脚本最前面加入". ~/.bash_profile"，结果报错：找不到/var/www/.bash_profile。
改为在脚本最前面加上". /etc/profile/"，可以正常编译。
看来用C实现权限互换，只是取得了root权限，当前用户还是apache，没有得到root的环境变量，需要额外导入。