PHP如何禁用函数？
PHP禁用函数的方法：首先打开“php.ini”配置文件；然后查找字符“disable_functions”，该字符是PHP禁用函数的配置项；接着在该配置项加上需要禁用的函数，多个函数用英文逗号分隔；最后保存重启即可。
推荐禁用的函数
disable_functions = system, exec, shell_exec, passthru, proc_open, proc_close, proc_get_status, checkdnsrr, getmxrr, getservbyname, getservbyport, syslog, popen, show_source, highlight_file, dl, socket_listen, socket_create, socket_bind, socket_accept, socket_connect, stream_socket_server, stream_socket_accept, stream_socket_client, ftp_connect, ftp_login, ftp_pasv, ftp_get, sys_getloadavg, disk_total_space, disk_free_space, posix_ctermid, posix_get_last_error, posix_getcwd, posix_getegid, posix_geteuid, posix_getgid, posix_getgrgid, posix_getgrnam, posix_getgroups, posix_getlogin, posix_getpgid, posix_getpgrp, posix_getpid, posix_getppid, posix_getpwnam, posix_getpwuid, posix_getrlimit, posix_getsid, posix_getuid, posix_isatty, posix_kill, posix_mkfifo, posix_setegid, posix_seteuid, posix_setgid, posix_setpgid, posix_setsid, posix_setuid, posix_strerror, posix_times, posix_ttyname, posix_uname
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