c语言发送邮件

c语言发送邮件

Linux下使用c语言发送邮件

领导交代一个任务，需要将服务器上的df -hl的执行结果定时发给他。

尝试使用sendmail来发邮件，但是后来放弃了，并不是所有的服务器上都安装了sendmail。

于是，就用c写一个吧，还能够指定邮件服务器地址和端口，会更灵活些。

目标是创建程序qmail，然后通过命令qmail my@163.com your.txt将your.txt的内容发送给my@163.com。

在网上找了半天，没有一个例子能够完全跑起来，有些是提问题的，最总问题解决了却不告诉别人，这人真可恨。

虽然这些代码都是复制粘贴来的，但是本着公益的宗旨，就不追究版权了。

1

2 #include <stdio.h>

3 #include <sys/socket.h>

4 #include <sys/types.h>

5 #include <netinet/in.h>

6 #include <stdlib.h>

7 #include <string.h>

8

9 int main(int argc,char *argv[])

10 {

11 int sockfd = -1;

12 int iconn = -2;

13 ssize_t retConnect = -2;

14 struct sockaddr_in servaddr;

15 char ip[20] = "192.168.0.251";//设置SMTP地址

16 char sentmsg[2048] = "";

17 char buf[255] = "";

18 char fileContent[1024] = "";

19 FILE* file;

20 char cin[255] = "";

21

22 int len = 0;

23 while(!(argv[len]==NULL))

24 {

25 len++;

26 }

27

28 if(len!=3)

29 {

30 printf("Usage:qmail yourname@163.com df.log\n");

31 exit(0);

32 }

33 memset(fileContent,'\0',sizeof(fileContent));

34 if((file = fopen(argv[2], "r")) == NULL)

35 printf("Not find file");

36 else

37 {

38 while(fgets(cin, sizeof(cin), file) != NULL)

39 {

40 strcat(fileContent,cin);

41 memset(cin,'\0',sizeof(cin));

42 }

43 }

44 fclose(file);

45 printf("%s",fileContent);

46 setvbuf(stdout,NULL,_IONBF,0);

47 sockfd = socket(AF_INET,SOCK_STREAM,0);//以scoket方式和邮件服务器通讯

48 if(sockfd>0)

49 {

50 printf("socket is open");

51 bzero(&servaddr,sizeof(servaddr));

52 servaddr.sin_family=AF_INET;

53 servaddr.sin_port=htons(25);

54 inet_pton(AF_INET,ip,&servaddr.sin_addr);

55 iconn = connect(sockfd,(struct sockaddr *)&servaddr,sizeof(servaddr));

56 if(iconn==0)

57 {

58 printf("connect to 192.168.0.251 25 success!");

59 retConnect = recv(sockfd,buf,sizeof(buf),0);

60 if(retConnect==-1)

61 {

62 printf("Failed to receive msg from smtp port");

63 }

64 else

65 printf("\nServer:%s\n",buf);

66 memset(sentmsg,'\0',sizeof(sentmsg));

67 strcpy(sentmsg,"HELO SERVER\r\n");

68 retConnect = send(sockfd,sentmsg,strlen(sentmsg),0);

69 if(retConnect==-1)

70 {

71 printf("\nFailed to send meg to smtp port in step 2.\n");

72 exit(1);

73 }

74 else

75 {

76 printf("%s",sentmsg);

77 }

78 memset(buf,'\0',sizeof(buf));

79 retConnect=recv(sockfd,buf,sizeof(buf),0);

80 if(retConnect == -1)

81 {

82 printf("\nFailed to recive meg from smtp port in step 3.\n");

83 exit(1);

84 }

85 else

86 {

87 printf("%s\n",buf);

88 }

89

90 memset(sentmsg,'\0',sizeof(sentmsg));

91 strcpy(sentmsg,"MAIL FROM: qdcm@163.com\r\n");

92 strcat(sentmsg,"RCPT TO: ");

93 strcat(sentmsg,argv[1]);

94 strcat(sentmsg,"\r\n");

95 retConnect = send(sockfd,sentmsg,strlen(sentmsg),0);

96 if(retConnect>0)

97 printf("%s",sentmsg);

98 memset(buf,'\0',sizeof(buf));

99 retConnect=recv(sockfd,buf,sizeof(buf),0);

100 if(retConnect>0)

101 printf("%s\n",buf);

102

103 memset(sentmsg,'\0',sizeof(sentmsg));

104 strcpy(sentmsg,"DATA\r\n");

105 retConnect = send(sockfd,sentmsg,strlen(sentmsg),0);

106 if(retConnect>0)

107 printf("%s",sentmsg);

108 memset(buf,'\0',sizeof(buf));

109 retConnect=recv(sockfd,buf,sizeof(buf),0);

110 if(retConnect>0)

111 printf("%s\n",buf);

112

113 memset(sentmsg,'\0',sizeof(sentmsg));

114 strcpy(sentmsg,"From:qdcm@163.com\r\n");

115 strcat(sentmsg,"To:");

116 strcat(sentmsg,argv[1]);

117 strcat(sentmsg,"\r\n");

118 strcat(sentmsg,"Subject:QDCM Host Check Data\r\n\r\n");

119 strcat(sentmsg,fileContent);

120 strcat(sentmsg,"\r\n");

121 strcat(sentmsg,"\r\n.\r\n");

122 retConnect = send(sockfd,sentmsg,strlen(sentmsg),0);

123 memset(sentmsg,'\0',sizeof(sentmsg));

124

125 strcpy(sentmsg,"QUIT\r\n");

126 retConnect = send(sockfd,sentmsg,strlen(sentmsg),0);

127 if(retConnect>0)

128 printf("%s",sentmsg);

129 memset(buf,'\0',sizeof(buf));

130 retConnect=recv(sockfd,buf,sizeof(buf),0);

131 if(retConnect>0)

132 printf("%s\n",buf);

133

134 }

135 else

136 {

137 printf("connect 192.168.0.251 25 failed!");

138 sleep(1);

139 }

140 close(sockfd);

141 }

142 else

143 {

144 printf("open socket failed!");

145 }

146 return 0;

147 }

148

使用gcc编译

如果你是在高版本的linux下编译的，在低版本上的linux使用时会报错

此时需要在编译时追加参数：

gcc -Wl,--hash-style=sysv qmail.c -o qmail