attachments.cpp

一个国外学生做的基于Web浏览器的email程序

#include "attachments.h"
#include "fullpipe.h"

void showattachment(char mailfile[], int mailnum, int attachnum)
{
	FILE * mailbox;
	char data[500];
	int count = 0;
	int attachcount = 0;
	char header[500];
	int attachfound = 0;
	passwd *info;


	mailbox = fopen(mailfile, "r");
	if (mailbox == NULL)
	{
		error("showattachment():can't open data for read.");
		return;
	}	
	if (bothlock(mailbox, 'r')!=0)
	{
		fclose(mailbox);
		error("showattachment():Error locking mailstore");
		return;		
	}
	info=getpwnam(globaluser);

	while (fgets(data, 500, mailbox) != NULL)
	{

		if (strncmp(data, "From ", 5)==0)
		{
			count++;
			if (count > mailnum)
				break;
		}
		if (count == mailnum) //email found
		{
			if (strncmp(data, "begin ", 6)==0) 		
			{ 
				attachcount++;
			}
			if (attachcount == attachnum)
			{
				snprintf(header, 500, "content-type: %s\n\n", guessmime(data));
				attachfound = 1;
				int pipe[2];

				char uudecodepath[500]; //not really needed
				char rdata[100];  //attach data
				snprintf(uudecodepath, 500, "/usr/bin/uudecode");

				char *arg[4];
				arg[0] = "uudecode";
				arg[1] = "-o";
				arg[2] = "/dev/stdout";
				arg[3] = '\0';

				//make sure file handles are flushed to prevent duplicate
				//output from buffers.
				fflush(stdout);
				fflush(stdin);

				if (fullpipe_arg(uudecodepath, arg, pipe))
				{
					error("showattachment(): Pipe error");
					return;
				}

				int forkresult;
				forkresult = fork();
				if (forkresult == (pid_t)-1) //error
				{
					error("showattachment(): fork error");

				}
				if (forkresult == (pid_t)0) //child writes
				{
					do
					{
						write(pipe[1], data, (size_t)(strlen(data)));
						if (strncmp(data, "end", 3)==0)
						{
							break;
						}
					} while (fgets(data, 500, mailbox) != NULL);
					close(pipe[1]);
					exit(0); //kill child
				}
				else //parent reads
				{
					close(pipe[1]); //prevents blocking
					attachcount++; //need to end
					fprintf(stdout, "%s", header);
 					fflush(stdout);

					int size;
 					while ((size = read(pipe[0], rdata, 99))>0)
 					{
						write(1, rdata, size);
 					}
					close(pipe[0]);
				}
			}
		}
	}

	bothunlock(mailbox);
	fclose(mailbox);

	if (attachfound == 0)
	{
		error("showattachment(): No attachment found");
	}
}
void mshowattachment(char mailfile[], int mailnum, int attachnum)
{
	int number; 	//email to read
	passwd *info;
	FILE *mailstore;
	char filename[400];
	char data[500];
	char contenttype[400];
	int count = 0;
	int attachcount = 0;

	int offofheader = 0; //mail header
	int extenddata = 0; //multi line headers
	int domarkold = 1;
	int onmimeheader = 0;
	int needsdecoding = 0;

	char answer[500];
	char boundary[300];
	boundary[0] = '-'; //sets up boundary
	boundary[1] = '-'; // "   "     "


	strncpy(contenttype, "text/plain\n", 399);

	mailstore = fopen(mailfile, "r");
	if (mailstore == NULL)
	{
		error("showinbox():ERROR while tring to read mail file");
		return;
	}	
	if (bothlock(mailstore, 'r')!=0)
	{
		fclose(mailstore);
		error("showinbox():Error while locking mail file.");
		return;
	}


	while (fgets(data, 499, mailstore) != NULL)
	{

		if (strncmp(data, "From ", 5)==0)
		{
			count++;
		}
		if (count == mailnum)
		{

			if (data[0] == '\n')
				offofheader = 1; 
			if (offofheader == 0) //in header
			{
				if (finddata(data, "boundary=", answer) != NULL)
				{
					int o = 0;
					if (answer[0] == '"')
						o++; //checks for" 
					strncpy(boundary+2, answer+o, 298);
					for (o = 0; o<299; o++)
					{ 		
						if (boundary[o] == '\n' ||
	 					boundary[o] == '"' ||
						boundary[o] == '\r' ||
						boundary[o] == '\0')	
						{ 			
							boundary[o] = '\0';
	 						break; 	
			 			}
 				
					}
  				}
			}
			else //out of header, in the email body in mime header
			{
				if (strncmp(data, boundary,strlen(boundary))==0)
 				{
					onmimeheader = 1;
					attachcount++;
		 		}
				if (attachcount == attachnum)
				{
					if (onmimeheader &&
					strncasecmp(data, "Content-Type: ", 14) == 0)
					{
						strncpy(contenttype, data+14, 399);
					}
					if (onmimeheader &&
					strncasecmp(data, "Content-Transfer-Encoding: base64",33)==0)
					{
						needsdecoding = 1;
					}

					if (onmimeheader == 0)
					{
						int pipe[2];
						char mimepath[500]; //not really needed
						char rdata[100];  //attach data
						char *arg[4];

						if (needsdecoding)
						{
							snprintf(mimepath, 500, "/usr/bin/mimencode");
							arg[0] = "mimencode";
							arg[1] = "-u";
							arg[2] = '\0';
						}
						else
						{
							snprintf(mimepath, 500, "/bin/cat");
							arg[0] = "cat";
							arg[1] = '\0';
						}
						//make sure file handles are flushed to prevent duplicate
						//output from buffers.
						fflush(stdout);
						fflush(stdin);

						if (fullpipe_arg(mimepath, arg, pipe))
						{
							error("showattachment(): Pipe error");
							return;
						}

						int forkresult;
						forkresult = fork();
						if (forkresult == (pid_t)-1) //error
						{
							error("showattachment(): fork error");
						}
						if (forkresult == (pid_t)0) //child writes
						{
							do
							{
								if (strncmp(data, boundary,strlen(boundary))==0)
								{
									break;
								}
								write(pipe[1], data, (size_t)(strlen(data)));
							} while (fgets(data, 500,mailstore) != NULL);
							close(pipe[1]);
							exit(0); //kill child
						}
						else //parent reads
						{
							close(pipe[1]); //prevents blocking
							attachcount++; //need to end
							int size;
							fflush(stdout);
 							while ((size = read(pipe[0], rdata, 99))>0)
 							{
								write(1, rdata, size);
 							}
							close(pipe[0]);
						}
					}
					if (onmimeheader && strncmp(data, "\n", 1) == 0)
					{
						cout << "Content-Type: ";
						cout << contenttype << endl;
						//contenttype has a return at end
						//already.
						onmimeheader = 0;
					}
				}
			}
		}//attach count == num
	} //while

	bothunlock(mailstore);
	fclose(mailstore);
	return;
}