/* batnews.c */ /* Andrew Davison, May 1997 (ad@ratree.psu.ac.th) */ /* Batch-oriented News-reader. The news-server specified in NEWS_SERVER is contacted and all new messages from the newsgroup in NEWS_GROUP are read. New messages are those numbered after the current value in NNUM_FNM. The articles are stored in NEW_FNM, and the news number file, NNUM_FNM, is updated to record the new number of the last article read. The NEW_FNM contents are then posted to the address in NEWS_RECEIVER. This relies on the UNIX utility /usr/bin/mail and its interactive option -I. */ #include #include #include #include #include #include #include /* for bcopy() */ #include /* for read(), write(), close() */ #define CR 13 /* carriage return ASCII value */ #define MAXSTR 512 /* max length of a string */ /* Configuration values */ #define NEWS_SERVER "news.psu.ac.th" /* location of news server */ #define NEWS_GROUP "rec.puzzles" /* news group of interest */ #define NNUM_FNM "/home/ad/ns/clp.num" /* news number file for newsgroup */ #define NEWS_FNM "/home/ad/ns/clp.news" /* file which stores articles */ #define NEWS_RECEIVER "ad@ratree.psu.ac.th" /* address to send NEWS_FNM */ /* function prototypes */ int open_news_socket(char *host, char *cmd); void set_group(int sd, int *last); void get_articles(int sd, int start, int end); void store_article(FILE *fp, int sd, int artnum); int is_period_line(char *line, int len); void store_error(FILE *fp, int artnum, int respno); void quit_server(int sd); int read_response(int sd, char response[], int success_code); int sdrline(char line[], int maxlen, int sd); int read_ninfo(void); void write_ninfo(int last_read); void mail_articles(void); int main(void) /* Open a socket link to news; set the newsgroup; store the articles in a file; send the file to the specified person by e-mail. When the socket is openned, the first line returned should start with 200 if the news link is good. */ { char response[MAXSTR]; int sd, last_read, last_in_group; last_read = read_ninfo(); sd = open_news_socket(NEWS_SERVER, "batnews"); if (read_response(sd, response, 200) == 200) { set_group(sd, &last_in_group); if (last_in_group <= last_read) printf("No new messages in %s\n", NEWS_GROUP); else { get_articles(sd, last_read+1, last_in_group); write_ninfo(last_in_group); mail_articles(); } } quit_server(sd); return 0; } int open_news_socket(char *host, char *cmd) /* Create a socket to the news server host. */ { struct sockaddr_in name; struct hostent *hptr; int sd; if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { perror(cmd); exit(1); } /* initialise the name struct to all zeros */ bzero(&name, sizeof(name)); /* memset(&name, 0, sizeof(name)); */ name.sin_family = AF_INET; name.sin_port = htons(119); /* host is a news-server */ if ((hptr = gethostbyname(host)) == NULL) { perror("gethostbyname"); exit(1); } /* copy the IP address of host into name */ bcopy(hptr->h_addr, &name.sin_addr.s_addr, hptr->h_length); /* memcpy(&name.sin_addr.s_addr, hptr->h_addr, hptr->h_length); */ /* name.sin_addr.s_addr = * (unsigned long *) hptr->h_addr; */ printf("Trying to contact %s...\n", host); if (connect(sd, (struct sockaddr *) &name, sizeof(name)) < 0) { close(sd); perror(cmd); exit(1); } return sd; } void set_group(int sd, int *last) /* Specify the newsgroup with the news server using the GROUP command: GROUP newsgroup-name The successful response has the form: 211 num-articles first-art-num last-art-num newsgroup-name e.g. 211 181 41289 43831 comp.protocols.tcp-ip */ { char msg[MAXSTR], response[MAXSTR]; sprintf(msg, "GROUP %s%c\n", NEWS_GROUP, CR); /* NNTP GROUP message */ printf("Sending: %s", msg); write(sd, msg, strlen(msg)); if (read_response(sd, response, 211) != 211) { quit_server(sd); exit(1); } if (sscanf(response, "%*d %*d %*d %d", last) != 1) { fprintf(stderr, "Error response: %s", response); quit_server(sd); exit(1); } } void get_articles(int sd, int start, int end) /* Get the text of the new articles numbered between start and end, and store them in NEWS_FNM. The NNTP command used is ARTICLE: ARTICLE news-number The response is the article, with the first line starting with a response number which is 220 for success. */ { FILE *fp; char msg[MAXSTR], response[MAXSTR]; int i, respno; if ((fp = fopen(NEWS_FNM, "w")) == NULL) fprintf(stderr, "Cannot write to %s\n", NEWS_FNM); else { printf("Will save %d articles in %s\n", end-start+1, NEWS_FNM); for (i=start; i <= end; i++) { sprintf(msg, "ARTICLE %d%c\n", i, CR); /* NNTP ARTICLE message */ printf("Sending: %s", msg); write(sd, msg, strlen(msg)); if ((respno = read_response(sd, response, 220)) == 220) store_article(fp, sd, i); else store_error(fp, i, respno); } fclose(fp); } } void store_article(FILE *fp, int sd, int artnum) /* Add the retrieved article to the end of the NEWS_FNM file. */ { char response[MAXSTR]; int rlen; printf("Saving article %d\n", artnum); fprintf(fp, "\n\n------------- %d -----------\n\n", artnum); rlen = sdrline(response, MAXSTR, sd); while (!is_period_line(response, rlen)) { response[rlen-2] = ' '; /* replace CR by space */ fprintf(fp, "%s", response); rlen = sdrline(response, MAXSTR, sd); } } int is_period_line(char *line, int len) /* A line consisting of ".CR\n" is the termination marker for variable length NNTP output. */ { if (len != 3) return 0; if ((line[0] == '.') && (line[1] == CR) && (line[2] == '\n')) return 1; return 0; } void store_error(FILE *fp, int artnum, int respno) /* Store the error code (in respno) obtained when reading an article */ { printf("Recording read error for article %d\n", artnum); fprintf(fp, "\n\n------------- %d -----------\n\n", artnum); fprintf(fp, "ARTICLE error: %d\n", respno); } void quit_server(int sd) /* Send the NNTP QUIT message */ { printf("Quiting %s\n", NEWS_SERVER); write(sd, "QUIT\015\n", 6); /* \015 is the octal for CR */ close(sd); } /* Input functions */ int read_response(int sd, char response[], int success_code) /* Read the response to a NNTP message and check it for errors. */ /* Return codenum (or -1) */ { int rlen, codenum; rlen = sdrline(response, MAXSTR, sd); if (rlen <= 0) { fprintf(stderr, "No response\n"); return -1; } if (sscanf(response, "%d", &codenum) != 1) { fprintf(stderr, "Incorrect response: %s", response); return -1; } if (codenum != success_code) fprintf(stderr, "Error response: %s", response); else printf("Response: %s", response); return codenum; } int sdrline(char line[], int maxlen, int sd) /* Read characters from a socket up (and including) the newline, or until there are maxlen-1 characters in line[]. Return the number of characters in line[]. */ { int posn = 0, rc; char ch; while (posn < (maxlen-1)) { rc = read(sd, &ch, 1); if (rc == 1) { /* character read successfully */ line[posn++] = ch; if (ch == '\n') break; } else if (rc == 0) /* socket closure */ break; else /* socket error */ return -1; } line[posn] = '\0'; return posn; } /* Interface functions for the news number file */ int read_ninfo(void) /* Read the number of the last article read from NNUM_FNM */ { int last_read; FILE *fp; if ((fp = fopen(NNUM_FNM, "r")) == NULL) { fprintf(stderr, "Cannot read %s\n", NNUM_FNM); exit(1); } printf("Reading %s\n", NNUM_FNM); fscanf(fp, "%d", &last_read); fclose(fp); printf("Last article read in %s: %d\n", NEWS_GROUP, last_read); return last_read; } void write_ninfo(int last_read) /* Write the last_read value into NNUM_FNM */ { FILE *fp; if ((fp = fopen(NNUM_FNM, "w")) == NULL) fprintf(stderr, "Cannot write to %s\n", NNUM_FNM); else { printf("Writing %d to %s\n", last_read, NNUM_FNM); fprintf(fp, "%d\n", last_read); fclose(fp); } } /* Mailer Component */ void mail_articles(void) /* Send articles in NEWS_FNM to NEWS_RECEIVER */ /* Use -I to run in interactive mode */ { char line[MAXSTR]; FILE *mfp; sprintf(line, "/usr/bin/mail -I -s \'%s News Articles\' %s", NEWS_GROUP, NEWS_RECEIVER); if ((mfp = popen(line, "w")) == NULL) fprintf(stderr, "popen() error for sending e-mail\n"); else { printf("Sending %s as e-mail to %s\n", NEWS_FNM, NEWS_RECEIVER); fprintf(mfp, "~r %s\n", NEWS_FNM); /* read news file */ fflush(mfp); pclose(mfp); } }