/*
**  MAIL2NEWS
**  Gateway mail messages into netnews.  Usage:
**	mail2news [inews flags] -o Organization
**  In order to do this, there are a number of interesting transformations
**  that need to be made on the headers...
**
**  This program is descended from:  @(#)recnews.c 2.10 4/16/85.
*/
#include "gate.h"
#include <signal.h>
#include <sys/file.h>
#if	defined(RCSID)
static char RCS[] =
	"$Header: /nfs/papaya/u2/rsalz/src/newsgate/RCS/mail2news.c,v 1.19 91/07/18 18:41:45 rsalz Exp Locker: rsalz $";
#endif	/* defined(RCSID) */


#define	WAIT_CORED(s)		(s & 0200)
#define	WAIT_EXITSIG(s)		(s & 0177)
#define	WAIT_EXITCODE(s)	((s >> 8) & 0377)

/* For those who don't have this in <sys/file.h>. */
#if	!defined(R_OK)
#define	R_OK			4
#endif	/* !defined(R_OK) */

/* Stuff for pipe(2). */
#define STDIN			0
#define	PIPE_READER		0
#define	PIPE_WRITER		1


/* Global variables. */
STATIC int	Debugging;
STATIC int	ChildPid = -1;
char		*Pname;



/*
**  Go down to the absolute minimum.
*/
STATIC void
TrimEnvironment()
{
    static char		*Empty[] = { NULL };

    environ = Empty;
}


/*
**  Quickie hack to see of a mail message is a "please drop me" request.
**  Reads the message on the input file, and returns NULL if it should
**  be ignored, or a FILE handle if we should process it.
**
**  The original stand-alone program written was Russ Nelson,
**  <nelson@clutx.clarkson.edu>.  I hacked on it, and made it into a
**  subroutine.  Perhaps a better way to test is to make the test less
**  conservative, and see what "real" articles get caught, and make
**  adjustments then?  Comments solicited.
*/
STATIC FILE *
IsSubRequest(F)
    register FILE	*F;
{
    register FILE	*Out;
    register char	*p;
    register int	c;
    register int	drop_or_add;
    register int	from_or_to;
    register int	mail_word;
    register int	count;
    char		word[SM_SIZE];
    char		buff[SM_SIZE];

    /* Create temp file; if we can't, let the message through. */
    Strcpy(buff, TEMPFILE);
    (void)mktemp(buff);
    if ((Out = fopen(buff, "w")) == NULL)
	return F;

    /* Clear counts. */
    drop_or_add = 0;
    from_or_to = 0;
    mail_word = 0;
    count = 0;

    /* Read input a word at a time. */
    for (p = word; (c = getc(F)) != EOF; ) {
	(void)putc(c, Out);
	if (!isalpha(c)) {
	    *p = '\0';
	    if (p > word)
		count++;
	    p = word;

	    if (EQ(word, "remove") || EQ(word, "drop") || EQ(word, "off")
	     || EQ(word, "subscribe") || EQ(word, "get") || EQ(word, "add"))
		drop_or_add++;
	    else if (EQ(word, "from") || EQ(word, "to"))
		from_or_to++;
	    else if (EQ(word, "mail") || EQ(word, "mailing")
		  || EQ(word, "list") || EQ(word, "dl"))
		mail_word++;
	}
	else if (p < &word[sizeof word - 1])
	    *p++ = isupper(c) ? tolower(c) : c;
    }

    (void)fclose(F);
    (void)fclose(Out);

    /* Use fancy-shmancy AI techniques to determine what the message is. */
    c = count < 25 && drop_or_add && from_or_to && mail_word;
    F = c ? NULL : fopen(buff, "r");

    (void)unlink(buff);
    return F;
}


/*
**  Modify the Newsgroups: as directed by the command string.
*/
STATIC void
DoCommand(hp, command, group)
    register HBUF		*hp;
    char			*command;
    char			*group;
{
    register char		*p;
    register int		i;
    register int		n;
    register int		nng;
    char			**tokens;
    char			**ng;
    char			buff[BUFSIZ];

    if ((n = Split(command, &tokens, '\0')) == 0) {
	SplitFree(&tokens);
	return;
    }

    nng = Split(hp->nbuf, &ng, NGDELIM);
    p = hp->nbuf;
    switch (tokens[0][0]) {
    case 'a':				/* Add		*/
	if (n > 1)
	    for (p += strlen(p), i = 1; i < n; i++) {
		*p++ = NGDELIM;
		p += APPEND(p, tokens[i]);
	    }
	break;
    case 'd':				/* Delete	*/
	for (i = 0; i < nng; i++)
	    if (!EQ(ng[i], group)) {
		if (p > hp->nbuf)
		    *p++ = NGDELIM;
		p += APPEND(p, ng[i]);
	    }
	if (p == hp->nbuf)
	    Strcpy(hp->nbuf, "junk");
	break;
    case 'k':				/* Kill		*/
	Fprintf(stderr, "%s:  Your posting to %s was killed by %s.\n",
	    Pname, hp->nbuf, n > 1 ? tokens[1] : group);
	exit(EX_NOPERM);
	/* NOTREACHED */
    case 'm':				/* Move		*/
	if (n > 1)
	    if (nng == 1)
		Strcpy(hp->nbuf, tokens[1]);
	    else
		for (i = 0; i < nng; i++) {
		    if (p > hp->nbuf)
			*p++ = NGDELIM;
		    p += APPEND(p, EQ(ng[i], group) ? tokens[1] : ng[i]);
		}
	break;
    case 'q':				/* Quiet kill	*/
	if (Debugging) {
	    (void)printf("Quiet kill (ignored for debugging).\n");
	    break;
	}
	/* Eat the message up, and pretend we delivered it. */
	while (fgets(buff, sizeof buff, stdin))
	    continue;
	exit(EX_OK);
	/* NOTREACHED */
    }

    SplitFree(&tokens);
    SplitFree(&ng);
}


/*
**  For Ozan Yigit's public domain regex.
*/
/* ARGSUSED */
void
re_fail(text, arg)
    char	*text;
    int		arg;
{
}


/*
**  Split a line that looks like XpatternXcommandX into the pattern and
**  the command.  Initialize the RE matcher with the pattern, and return
**  the command.
*/
STATIC char *
ParsePattern(p, lineno)
    register char	*p;
    int			lineno;
{
    register char	*cp;
    register char	*command;
    register char	delim;
    char		*RE;

    /* Ignore comments and blank lines. */
    if (*p == '#' || *p == '\0')
	return NULL;

    for (delim = *p++, RE = cp = p, command = NULL; *cp; *p++ = *cp++)
	if (*cp == '\\' && cp[1] == delim)
	    cp++;
	else if (*cp == delim) {
	    /* Found delimiter; mark command, terminate RE. */
	    command = ++cp;
	    *p = '\0';
	    break;
	}

    if (command == NULL || *command == '\0')
	Fprintf(stderr, "%s:  Incomplete regular expression, line %d.\n",
	    Pname, lineno);
    else if ((cp = re_comp(RE)) != NULL)
	Fprintf(stderr, "%s:  Bad regular expression, line %d: %s.\n",
	    Pname, lineno, cp);
    else
	return command;

#if	defined(lint)
    /* My, my, aren't we anal. */
    (void)re_subs("", "");
    re_modw("");
#endif	/* defined(lint) */

    return NULL;
}


/*
**  Convert string to lower case, return a new copy.
*/
STATIC char *
MakeLowerCopy(s)
    register char	*s;
{
    register char	*p;

    for (p = s = COPY(s); *p; p++)
	if (isupper(*p))
	    *p = tolower(*p);
    return s;
}


/*
**  Free up something that ReadFile made.
*/
void
FreeFile(V)
    char		**V;
{
    register char	**p;

    if ((p = V) != NULL) {
	while (*p)
	    free(*p++);
	free((char *)V);
    }
}


/*
**  Change newsgroups if the Subject:, Keywords:, or Summary: match a
**  pattern found in the newsgroup remap file.
*/
STATIC void
Editnewsgroups(hp)
    register HBUF		*hp;
{
    register char		*p;
    register int		n;
    register int		i;
    register int		j;
    register int		t;
    char			**groups;
    char			**mapline;
    char			*hdrline[4];
    char			buff[LG_SIZE];

    /* Copy some headers, but if nothing's there, give up. */
    i = 0;
    if (hp->title[0])
	hdrline[i++] = MakeLowerCopy(hp->title);
    if (hp->keywords[0])
	hdrline[i++] = MakeLowerCopy(hp->keywords);
    if (hp->summary[0])
	hdrline[i++] = MakeLowerCopy(hp->summary);
    if (i == 0)
	return;
    hdrline[i] = NULL;

    /* For all the newsgroups, see if there's a mapping file. */
    for (n = Split(hp->nbuf, &groups, NGDELIM), i = 0; i < n; i++) {
	if (groups[i] == NULL || groups[i][0] == '\0')
	    continue;

	/* Gate the name of the mapping file. */
#if	defined(IN_ONEPLACE)
	Strcpy(buff, IN_ONEPLACE);
#endif	/* defined(IN_ONEPLACE) */
#if	defined(IN_SPOOLDIR)
	{
	    register char	*q;

	    for (p = buff + APPEND(buff, IN_SPOOLDIR), q = groups[i]; *q; q++)
		*p++ = *q == '.' ? '/' : *q;
	    Strcpy(p, "/recnews.cmd");
	}
#endif	/* defined(IN_SPOOLDIR) */
#if	defined(IN_CMDDIR)
	Sprintf(buff, "%s/%s", IN_CMDDIR, groups[i]);
#endif	/* defined(IN_CMDDIR) */

	if (access(buff, R_OK) >= 0 && (mapline = ReadFile(buff))) {
	    /* For all lines in the file, if there's a command and the
	     * pattern matches, execute the command. */
	    for (j = 0; mapline[j]; j++)
		if ((p = ParsePattern(mapline[j], j)) != NULL)
		    for (t = 0; hdrline[t]; t++)
			if (re_exec(hdrline[t]) == 1) {
			    DoCommand(hp, p, groups[i]);
			    break;
			}
	    FreeFile(mapline);
	}
    }

    /* Free dynamic space. */
    for (i = 0; hdrline[i]; i++)
	free(hdrline[i]);
    SplitFree(&groups);
}


/*
**  Signal-catcher and child-reapers.
*/


/*
**  Exit such that sendmail will again later.
*/
STATIC CATCHER
Sig_tempfail()
{
    exit(EX_TEMPFAIL);
}


/*
**  Reap the inews child properly, and exit with his exit code, so that
**  ultimate success or failure rests with inews.
*/
STATIC CATCHER
childgone()
{
    register int	pid;
    int			W;

    /* Some systems get race conditions, causing this routine to be
     * invoke multiple times, sigh.  Some systems want SIG_IGN, I think. */
#if	defined(SIGCHLD)
    Signal(SIGCHLD, SIG_DFL);
#endif	/* defined(SIGCHLD) */
#if	defined(SIGCLD)
    Signal(SIGCLD, SIG_DFL);
#endif	/* defined(SIGCLD) */

    if ((pid = wait(&W)) != ChildPid || pid == -1)
	exit(EX_OSERR);
    
    /* Was it a good death? */
    if (WAIT_EXITSIG(W)) {
	Fprintf(stderr, "%s:  Child %d killed by signal %d.\n",
	    Pname, pid, WAIT_EXITSIG(W));
	if (WAIT_CORED(W))
	    Fprintf(stderr, "%s:  Child %d dumped core.\n", Pname, pid);
	exit(EX_SOFTWARE);
    }

#if	defined(MMDF)
    /* We need a way to tell temporary errors from permanent ones.  Inews
     * will reject messages because of too much quoting, for example,
     * so the message will sit in the queue forever.  Until then we'll
     * have to lose messages on any error. */
    exit(0);
#else
    exit(WAIT_EXITCODE(W));
#endif	/* defined(MMDF) */
}



/*
**  Convert the characters following dots to upper case, if they're
**  lower case.  Two dots in a row will leave one dot in their place.
**  Modifies the argument.
*/
STATIC char *
HackPeriods(string)
    char		*string;
{
    register char	*s;
    register char	*p;

    if (string) {
	for (p = s = string; *p; *s++ = *p++)
	    if (*p == '.') {
		if (*++p == '\0') {
		    *s++ = '.';
		    break;
		}
		if (islower(*p))
		    *p = toupper(*p);
	    }
	*s = '\0';
    }
    return string;
}



int
main(ac, av)
    register int	ac;
    register char	*av[];
{
    register STRING	*vec;
    register char	*p;
    register FILE	*F;
    register FILE	*Infile;
    HBUF		H;
    STRING		*iv;
    char		buff[BUFSIZ];
#if	defined(SENDMAIL)
    char		sendbuff[sizeof buff];
#endif	/* defined(SENDMAIL) */
    int			fd[2];
    int			FlushSubRequests;
    int			SubjectRequired;
    int			GotEquals;
    STRING		error;

    if ((Pname = RDX(av[0], '/')) == NULL)
	Pname = av[0];
    else
	Pname++;
    Infile = stdin;

    /* Remove any trace of who we are. */
    TrimEnvironment();

    /* So that cores will actually drop... */
    if (chdir("/tmp") < 0) {
	Fprintf(stderr, "%s:  Can't chdir(/tmp), %s.\n", Pname,
	    strerror(errno));
	exit(EX_TEMPFAIL);
    }

    /* If someone wants to shut down the system, tell sendmail to
     * try again later. */
    Signal(SIGTERM, Sig_tempfail);

#if	defined(SENDMAIL)
    /* First read should fetch us the UNIX From_ line.  Not done in MMDF. */
    if (fgets(buff, sizeof buff, Infile) == NULL)
	exit(EX_NOINPUT);

#if	defined(REQUIRE_UNIX_FROM)
    if (!EQn(buff, "From ", 5)) {
	Fprintf(stderr, "%s:  Input didn't start with UNIX From line:\n",
	    Pname);
	Fprintf(stderr,"\t%s.\n", buff);
	exit(EX_DATAERR);
    }
#endif	/* defined(REQUIRE_UNIX_FROM) */

    /* Turn "From foo ... remote from bar ..." into "Sender: bar!foo". */
    if (EQn(buff, "From ", 5)) {
	Strcpy(sendbuff, "Sender: ");
	for (p = buff + 4; (p = IDX(p + 1, 'r')) != NULL; )
	    if (strncmp(p, "remote from ", 12) == 0
	     && sscanf(p, "remote from %s", sendbuff + 8) == 1) {
		Strcat(sendbuff, "!");
		break;
	    }
	if (sscanf(buff, "From %s", sendbuff + strlen(sendbuff)) == 1)
	    Strcpy(buff, sendbuff);
    }
#endif	/* defined(SENDMAIL) */

    /* Read the mail header. */
    rfc822read(&H, Infile, buff, sizeof buff);

    /* Process the argument list, copying anything that we don't recognize
     * over to the inews argument list and changing things as we see fit. */
    FlushSubRequests = FALSE;
    GotEquals = FALSE;
    SubjectRequired = TRUE;
    iv = NEW(STRING, ac + 2);
    iv[0] = INEWS;
#if	!defined(NO_H_FLAG)
    iv[1] = "-h";
#endif	/* defined(NO_H_FLAG) */
    for (vec = iv + 2; (p = *++av) != NULL; )
	if (p[0] != '-')
	    *vec++ = p;
	 else
	    switch(p[1]) {
	    case 'x':
		SubjectRequired = FALSE;
		/* FALLTHROUGH */
	    default:
		*vec++ = p;
		break;
	    case '=':
#if	!defined(NO_H_FLAG)
		/* Move past the old iv[0], and set the new iv[0] to be
		 * the program to run. */
		if (!GotEquals)
		    iv++;
#endif	/* defined(NO_H_FLAG) */
		iv[0] = p[2] ? &p[2] : *++av;
		GotEquals++;
		break;
	    case '.':
		Debugging++;
		break;
	    case 'n':
		/* Newsgroup this messages goes to. */
		Strcpy(H.nbuf, p[2] ? &p[2] : *++av);
		break;
	    case 'o':
		/* Default organization. */
		p = p[2] ? &p[2] : *++av;
		if (H.organization[0] == '\0')
		    Strcpy(H.organization, HackPeriods(p));
		SubjectRequired = FALSE;
		break;
	    case 'd':
		/* Default distribution. */
		p = p[2] ? &p[2] : *++av;
		if (H.distribution[0] == '\0')
		    Strcpy(H.distribution, p);
		break;
	    case 'a':
		/* Default approval. */
		p = p[2] ? &p[2] : *++av;
		if (H.approved[0] == '\0')
		    Strcpy(H.approved, p);
		break;
	    case 'F':
		FlushSubRequests = TRUE;
		break;
	    }
    *vec++ = NULL;

    /* Bash on the mail header. */
    if ((error = HackHeader(&H, SubjectRequired)) != NULL) {
	Fprintf(stderr, "%s:  Rejected by netnews because:\n", Pname);
	Fprintf(stderr, "\t%s.\n", error);
	if (H.nbuf[0])
	    Fprintf(stderr, "\tIt was going into the newsgroup%s %s.\n",
		IDX(H.nbuf, NGDELIM) ? "s" : "", H.nbuf);
	exit(EX_DATAERR);
    }
    Editnewsgroups(&H);

    if (Debugging) {
	for (vec = iv; *vec; vec++)
	    (void)printf(" |%s| ", *vec);
	(void)printf("\n");
	if (!rfc822write(&H, stdout))
	    Fprintf(stderr, "%s:  Can't write header, %s.\n",
		Pname, strerror(errno));
	while (fgets(buff, sizeof buff, Infile))
	    Fputs(buff, stdout);
	exit(EX_OK);
    }

    if (FlushSubRequests && (Infile = IsSubRequest(Infile)) == NULL) {
	Fprintf(stderr, "%s:  Rejected by netnews becase:\n", Pname);
	Fprintf(stderr, "\tIt seems like a subscription request.\n");
	exit(EX_DATAERR);
    }

    /* Get ready to spawn an inews. */
    if (pipe(fd) < 0) {
	Fprintf(stderr, "%s:  Can't pipe, %s.\n", Pname, strerror(errno));
	exit(EX_TEMPFAIL);
    }
    Fflush(stderr);
    Fflush(stdout);
#if	defined(SIGCHLD)
    Signal(SIGCHLD, childgone);
#endif	/* defined(SIGCHLD) */
#if	defined(SIGCLD)
    Signal(SIGCLD, childgone);
#endif	/* defined(SIGCLD) */

    if ((ChildPid = fork()) < 0) {
	Fprintf(stderr,"%s:  Can't fork, %s.\n", Pname, strerror(errno));
	exit(EX_TEMPFAIL);
    }
    if (ChildPid == 0) {
	/* Redirect I/O; it's unlikely the test below will fail. */
	if (fd[PIPE_READER] != STDIN) {
	    Close(STDIN);
	    if (dup(fd[PIPE_READER]) != STDIN)
		Fprintf(stderr, "%s:  Can't redirect input, %s.\n",
		    Pname, strerror(errno));
	}
	Close(fd[PIPE_READER]);
	Close(fd[PIPE_WRITER]);
	(void)execv(iv[0], iv);
	Fprintf(stderr, "%s:  Can't exec %s, %s.\n",
	    Pname, iv[0], strerror(errno));
	exit(EX_OSERR);
    }

    /* Set things up after the fork. */
    Close(fd[PIPE_READER]);
    Signal(SIGPIPE, childgone);
    if ((F = fdopen(fd[PIPE_WRITER], "w")) == NULL)
	exit(EX_OSERR);

    /* Stuff the header. */
    if (!rfc822write(&H, F)) {
	Fprintf(stderr, "%s:  Can't write header, %s.\n",
	    Pname, strerror(errno));
	exit(EX_IOERR);
    }

    /* Write the rest of the message. */
    while (fgets(buff, sizeof buff, Infile)) {
	Fputs(buff, F);
	if (ferror(F))
	    break;
    }

    /* Close down the pipe. */
    Fflush(F);
    if (ferror(F)) {
	Fprintf(stderr, "%s:  Error flushing pipe to news, %s.\n",
	    Pname, strerror(errno));
	exit(EX_IOERR);
    }
    if (fclose(F) == EOF)
	Fprintf(stderr, "%s:  Error closing pipe to news, %s.\n",
	    Pname, strerror(errno));

    /* Wait for inews, and exit as it does. */
    childgone();
    return 0;
}