（P07）miniftpd项目实战：实现客户端发送过来的某些应答

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喜欢打篮球的普通人 2023-03-09 09:49:43 博主文章分类：开源代码学习 ©著作权

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文章目录

1.实现客户端发送过来的某些应答

1.实现客户端发送过来的某些应答

eg：
ftpproto.h

#ifndef _FTP_PROTO_H_
#define _FTP_PROTO_H_

#include "session.h"

void handle_child(session_t *sess);

#endif /* _FTP_PROTO_H_ */

ftpproto.c

#include "ftpproto.h"
#include "sysutil.h"
#include "str.h"
#include "ftpcodes.h"

void ftp_reply(session_t *sess, int status, const char *text);
static void do_user(session_t *sess);
static void do_pass(session_t *sess);

void handle_child(session_t *sess)
{
  ftp_reply(sess, FTP_GREET, "(miniftpd 0.1)");
  int ret;
  while (1)
  {
    memset(sess->cmdline, 0, sizeof(sess->cmdline));
    memset(sess->cmd, 0, sizeof(sess->cmd));
    memset(sess->arg, 0, sizeof(sess->arg));
    ret = readline(sess->ctrl_fd, sess->cmdline, MAX_COMMAND_LINE);
    if (ret == -1)
      ERR_EXIT("readline");
    else if (ret == 0)
      exit(EXIT_SUCCESS);

    printf("cmdline=[%s]\n", sess->cmdline);
    // 去除\r\n
    str_trim_crlf(sess->cmdline);
    printf("cmdline=[%s]\n", sess->cmdline);
    // 解析FTP命令与参数
    str_split(sess->cmdline, sess->cmd, sess->arg, ' ');
    printf("cmd=[%s] arg=[%s]\n", sess->cmd, sess->arg);
    // 将命令转换为大写
    str_upper(sess->cmd);
    // 处理FTP命令
    if (strcmp("USER", sess->cmd) == 0)
    {
      do_user(sess);
    }
    else if (strcmp("PASS", sess->cmd) == 0)
    {
      do_pass(sess);
    }
  }
}

//代码+状态+文本
void ftp_reply(session_t *sess, int status, const char *text)
{
  char buf[1024] = {0};
  sprintf(buf, "%d %s\r\n", status, text);
  writen(sess->ctrl_fd, buf, strlen(buf));
}

//static表面：该函数只能用于当前模块
static void do_user(session_t *sess)
{
  //USER jjl
  //getpwnam依据用户名，可以获取到密码的结构体
  struct passwd *pw = getpwnam(sess->arg);//man getpwnam,这与cat /etc/passwd文件相对应
  if (pw == NULL)//获取失败
  {
    // 用户不存在
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }

  sess->uid = pw->pw_uid;
  ftp_reply(sess, FTP_GIVEPWORD, "Please specify the password.");
  
}

static void do_pass(session_t *sess)
{
  // PASS 123456
  //getpwuid根据uid得到passwd结构体
  struct passwd *pw = getpwuid(sess->uid);//man getpwuid
  if (pw == NULL)
  {
    // 用户不存在
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }

  printf("name=[%s]\n", pw->pw_name);
  //getspnam依据用户名，来获取影子passwd文件信息
  //pw->pw_name是用户名
  struct spwd *sp = getspnam(pw->pw_name);//获取/etc/passwd文件信息
  if (sp == NULL)
  {
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }

  // 将明文进行加密
  //加密crypt(要加密的明文，种子)，将加密过的密码做为种子，得到一个加密的密码
  char *encrypted_pass = crypt(sess->arg, sp->sp_pwdp);
  // 验证密码
  if (strcmp(encrypted_pass, sp->sp_pwdp) != 0)
  {
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }
  
  //登录成功后，需要左的动作，下面的参数可以从man getpwnam中获取到
  setegid(pw->pw_gid);
  seteuid(pw->pw_uid);
  chdir(pw->pw_dir);
  ftp_reply(sess, FTP_LOGINOK, "Login successful.");
}

session.h

#ifndef _SESSION_H_
#define _SESSION_H_

#include "common.h"

typedef struct session
{
  // 控制连接
  uid_t uid;
  int ctrl_fd;
  char cmdline[MAX_COMMAND_LINE];
  char cmd[MAX_COMMAND];
  char arg[MAX_ARG];

  // 父子进程通道
  int parent_fd;
  int child_fd;
} session_t;

void begin_session(session_t *sess);

#endif /* _SESSION_H_ */

session.c

#include "common.h"
#include "session.h"
#include "ftpproto.h"
#include "privparent.h"

void begin_session(session_t *sess)
{
  int sockfds[2];
  if (socketpair(PF_UNIX, SOCK_STREAM, 0, sockfds) < 0)
    ERR_EXIT("socketpair");


  pid_t pid;
  pid = fork();
  if (pid < 0)
    ERR_EXIT("fork");

  if (pid == 0)
  {
    // ftp服务进程
    close(sockfds[0]);
    sess->child_fd = sockfds[1];
    handle_child(sess);
  }
  else
  {
    struct passwd *pw = getpwnam("nobody");
    if (pw == NULL)
      return;

    if (setegid(pw->pw_gid) < 0)
      ERR_EXIT("setegid");
    if (seteuid(pw->pw_uid) < 0)
      ERR_EXIT("seteuid");
    // nobody进程
    close(sockfds[1]);
    sess->parent_fd = sockfds[0];
    handle_parent(sess);
  }
}

main.c

#include "common.h"
#include "sysutil.h"
#include "session.h"
#include "str.h"
#include "tunable.h"
#include "parseconf.h"

/*
typedef struct session
{
  // 控制连接
  char cmdline[MAX_COMMAND_LINE];
  char cmd[MAX_COMMAND];
  char arg[MAX_ARG];

  // 父子进程通道
  int parent_fd;
  int child_fd;
} session_t;
*/


int main(void)
{
  // 字符串测试
  /*
  char *str1 = "    a b";
  char *str2 = "        ";

  if (str_all_space(str1))
    printf("str1 all space\n");
  else
    printf("str1 not all space\n");

  if (str_all_space(str2))
    printf("str2 all space\n");
  else
    printf("str2 not all space\n");

  //char *str3 = "abcDef";    // 指针指向一个字符串常量，常量不能被修改
  char str3[] = "abcDef";
  str_upper(str3);
  printf("str3=%s\n", str3);

  long long result = str_to_longlong("12345678901234");
  printf("result = %lld\n", result);


  int n = str_octal_to_uint("711");
  printf("n=%d\n", n);
  */

  parseconf_load_file(MINIFTP_CONF);

  printf("tunable_pasv_enable=%d\n", tunable_pasv_enable);
  printf("tunable_port_enable=%d\n", tunable_port_enable);

  printf("tunable_listen_port=%u\n", tunable_listen_port);
  printf("tunable_max_clients=%u\n", tunable_max_clients);
  printf("tunable_max_per_ip=%u\n", tunable_max_per_ip);
  printf("tunable_accept_timeout=%u\n", tunable_accept_timeout);
  printf("tunable_connect_timeout=%u\n", tunable_connect_timeout);
  printf("tunable_idle_session_timeout=%u\n", tunable_idle_session_timeout);
  printf("tunable_data_connection_timeout=%u\n", tunable_data_connection_timeout);
  printf("tunable_local_umask=0%o\n", tunable_local_umask);
  printf("tunable_upload_max_rate=%u\n", tunable_upload_max_rate);
  printf("tunable_download_max_rate=%u\n", tunable_download_max_rate);

  if (tunable_listen_address == NULL)
    printf("tunable_listen_address=NULL\n");
  else
    printf("tunable_listen_address=%s\n", tunable_listen_address);


  if (getuid() != 0)
  {
    fprintf(stderr, "miniftpd: must be started as root\n");
    exit(EXIT_FAILURE);
  }

/*
typedef struct session
{
  // 控制连接
  uid_t uid;
  int ctrl_fd;
  char cmdline[MAX_COMMAND_LINE];
  char cmd[MAX_COMMAND];
  char arg[MAX_ARG];

  // 父子进程通道
  int parent_fd;
  int child_fd;
} session_t;
*/
  session_t sess = 
  {
    /* 控制连接 */
    0, -1, "", "", "",
    /* 父子进程通道 */
    -1, -1
  };
  
  int listenfd = tcp_server(tunable_listen_address, tunable_listen_port);
  int conn;
  pid_t pid;

  while (1)
  {
    conn = accept_timeout(listenfd, NULL, 0);
    if (conn == -1)
      ERR_EXIT("accept_tinmeout");

    pid = fork();
    if (pid == -1)
      ERR_EXIT("fork");

    if (pid == 0)
    {
      close(listenfd);
      sess.ctrl_fd = conn;
      begin_session(&sess);
    }
    else
      close(conn);
  }
  return 0;
}

ftpcodes.h

#ifndef _FTP_PROTO_H_
#define _FTP_PROTO_H_

#include "session.h"

void handle_child(session_t *sess);

#endif /* _FTP_PROTO_H_ */

ftpproto.c

#include "ftpproto.h"
#include "sysutil.h"
#include "str.h"
#include "ftpcodes.h"

void ftp_reply(session_t *sess, int status, const char *text);
static void do_user(session_t *sess);
static void do_pass(session_t *sess);

void handle_child(session_t *sess)
{
  ftp_reply(sess, FTP_GREET, "(miniftpd 0.1)");
  int ret;
  while (1)
  {
    memset(sess->cmdline, 0, sizeof(sess->cmdline));
    memset(sess->cmd, 0, sizeof(sess->cmd));
    memset(sess->arg, 0, sizeof(sess->arg));
    ret = readline(sess->ctrl_fd, sess->cmdline, MAX_COMMAND_LINE);
    if (ret == -1)
      ERR_EXIT("readline");
    else if (ret == 0)
      exit(EXIT_SUCCESS);

    printf("cmdline=[%s]\n", sess->cmdline);
    // 去除\r\n
    str_trim_crlf(sess->cmdline);
    printf("cmdline=[%s]\n", sess->cmdline);
    // 解析FTP命令与参数
    str_split(sess->cmdline, sess->cmd, sess->arg, ' ');
    printf("cmd=[%s] arg=[%s]\n", sess->cmd, sess->arg);
    // 将命令转换为大写
    str_upper(sess->cmd);
    // 处理FTP命令
    if (strcmp("USER", sess->cmd) == 0)
    {
      do_user(sess);
    }
    else if (strcmp("PASS", sess->cmd) == 0)
    {
      do_pass(sess);
    }
  }
}

//代码+状态+文本
void ftp_reply(session_t *sess, int status, const char *text)
{
  char buf[1024] = {0};
  sprintf(buf, "%d %s\r\n", status, text);
  writen(sess->ctrl_fd, buf, strlen(buf));
}

//static表面：该函数只能用于当前模块
static void do_user(session_t *sess)
{
  //USER jjl
  //getpwnam依据用户名，可以获取到密码的结构体
  struct passwd *pw = getpwnam(sess->arg);//man getpwnam,这与cat /etc/passwd文件相对应
  if (pw == NULL)//获取失败
  {
    // 用户不存在
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }

  sess->uid = pw->pw_uid;
  ftp_reply(sess, FTP_GIVEPWORD, "Please specify the password.");
  
}

static void do_pass(session_t *sess)
{
  // PASS 123456
  //getpwuid根据uid得到passwd结构体
  struct passwd *pw = getpwuid(sess->uid);//man getpwuid
  if (pw == NULL)
  {
    // 用户不存在
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }

  printf("name=[%s]\n", pw->pw_name);
  //getspnam依据用户名，来获取影子passwd文件信息
  //pw->pw_name是用户名
  struct spwd *sp = getspnam(pw->pw_name);//获取/etc/passwd文件信息
  if (sp == NULL)
  {
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }

  // 将明文进行加密
  //加密crypt(要加密的明文，种子)，将加密过的密码做为种子，得到一个加密的密码
  char *encrypted_pass = crypt(sess->arg, sp->sp_pwdp);
  // 验证密码
  if (strcmp(encrypted_pass, sp->sp_pwdp) != 0)
  {
    ftp_reply(sess, FTP_LOGINERR, "Login incorrect.");
    return;
  }
  
  //登录成功后，需要左的动作，下面的参数可以从man getpwnam中获取到
  setegid(pw->pw_gid);
  seteuid(pw->pw_uid);
  chdir(pw->pw_dir);
  ftp_reply(sess, FTP_LOGINOK, "Login successful.");
}

ftpcodes.h

#ifndef _FTP_CODES_H_
#define _FTP_CODES_H_


#define FTP_DATACONN          150

#define FTP_NOOPOK            200
#define FTP_TYPEOK            200
#define FTP_PORTOK            200
#define FTP_EPRTOK            200
#define FTP_UMASKOK           200
#define FTP_CHMODOK           200
#define FTP_EPSVALLOK         200
#define FTP_STRUOK            200
#define FTP_MODEOK            200
#define FTP_PBSZOK            200
#define FTP_PROTOK            200
#define FTP_OPTSOK            200
#define FTP_ALLOOK            202
#define FTP_FEAT              211
#define FTP_STATOK            211
#define FTP_SIZEOK            213
#define FTP_MDTMOK            213
#define FTP_STATFILE_OK       213
#define FTP_SITEHELP          214
#define FTP_HELP              214
#define FTP_SYSTOK            215
#define FTP_GREET             220
#define FTP_GOODBYE           221
#define FTP_ABOR_NOCONN       225
#define FTP_TRANSFEROK        226
#define FTP_ABOROK            226
#define FTP_PASVOK            227
#define FTP_EPSVOK            229
#define FTP_LOGINOK           230
#define FTP_AUTHOK            234
#define FTP_CWDOK             250
#define FTP_RMDIROK           250
#define FTP_DELEOK            250
#define FTP_RENAMEOK          250
#define FTP_PWDOK             257
#define FTP_MKDIROK           257

#define FTP_GIVEPWORD         331
#define FTP_RESTOK            350
#define FTP_RNFROK            350

#define FTP_IDLE_TIMEOUT      421
#define FTP_DATA_TIMEOUT      421
#define FTP_TOO_MANY_USERS    421
#define FTP_IP_LIMIT          421
#define FTP_IP_DENY           421
#define FTP_TLS_FAIL          421
#define FTP_BADSENDCONN       425
#define FTP_BADSENDNET        426
#define FTP_BADSENDFILE       451

#define FTP_BADCMD            500
#define FTP_BADOPTS           501
#define FTP_COMMANDNOTIMPL    502
#define FTP_NEEDUSER          503
#define FTP_NEEDRNFR          503
#define FTP_BADPBSZ           503
#define FTP_BADPROT           503
#define FTP_BADSTRU           504
#define FTP_BADMODE           504
#define FTP_BADAUTH           504
#define FTP_NOSUCHPROT        504
#define FTP_NEEDENCRYPT       522
#define FTP_EPSVBAD           522
#define FTP_DATATLSBAD        522
#define FTP_LOGINERR          530
#define FTP_NOHANDLEPROT      536
#define FTP_FILEFAIL          550
#define FTP_NOPERM            550
#define FTP_UPLOADFAIL        553


#endif /* _FTP_CODES_H_ */

Makefile

.PHONY:clean
CC=gcc
CFLAGS=-Wall -g
BIN=miniftpd
OBJS=main.o sysutil.o session.o ftpproto.o privparent.o str.o tunable.o parseconf.o
LIBS=-lcrypt

$(BIN):$(OBJS)
  $(CC) $(CFLAGS) $^ -o $@ $(LIBS)
%.o:%.c
  $(CC) $(CFLAGS) -c $< -o $@
clean:
  rm -f *.o $(BIN)

下面的文件与上一节一样，不再列出
privparent.h
privparent.c
tunable.h
tunable.c
sysutil.h
sysutil.c
str.h
str.c
miniftpd.conf