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。
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
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