DataMuseum.dk

top - metrics - download

    Length: 4228 (0x1084)
    Types: TextFile
    Names: »fakename.c«

└─⟦9ae75bfbd⟧ Bits:30007242 EUUGD3: Starter Kit
    └─⟦bfebc70e2⟧ »EurOpenD3/mail/sendmail-5.65b+IDA-1.4.3.tar.Z« 
        └─⟦f9e35cd84⟧ 
            └─⟦this⟧ »sendmail/support/fakename.c« 

TextFile

/*
** fakemail - a SysV /bin/mail preprocessor for sendmail
**
** Standard AT&T /bin/mail adds it's own From_ line specifying the
** identity of the sender (commenting out any previously existing
** From_ lines in the process).  While this behavior might be
** consistent with RFC-976, it only serves to confuse mailers such
** as mailx which use the From_ line to determine reply addresses.
**
** To determine the sender identity (placed in the generated From_
** line), /bin/mail uses $LOGNAME of the user/program invoking it. 
** For local mail this is moderately acceptable (the user could fake
** the sender by changing $LOGNAME), but for use with sendmail this
** behavior is unreasonable since the invocation of /bin/mail is
** done by root.  As a result, mailx reports all external mail as
** "From root", and the actual identity of the sender is obscured.
**
** `fakemail' is designed as a replacement for the sendmail local
** delivery program.  It preprocesses mail messages (read from
** stdin) and changes $LOGNAME before calling the regular /bin/mail.
** The new $LOGNAME is derived from the address portion of the From_
** line, which is found in the first line of the header.
**
**	From user@site Fri Jun 15 13:18:09 1990
**
** If no From_ line is found, $LOGNAME defaults to the user of the
** program, as with normal /bin/mail.
**
** Technically, `fakemail' could be considered a slightly better
** mechanism than direct /bin/mail since you cannot spoof the
** program by changing $LOGNAME.  An argument against this, however,
** is the fact that you *can* trick `fakemail' by supplying a bogus
** From_ line as the first line of the header.
**
** To use:
**
**	1) Compile and install this program
**		make fakemail
**		cpset fakemail /usr/bin
**
**	2) Edit /usr/lib/sendmail.cf
**		change the 'Mlocal' mailer to use /usr/bin/fakemail
**
**	3) Restart sendmail
**		ps -eaf; kill -9 <sendmail_pid>
**		/usr/lib/sendmail -bd -q30m
**
** NOTE: This is simply a hack for sendmail+mailx.  Use of another
** MTA (ie, smail) or MUA (ie, Elm) would eliminate any need for this
** program.
**
** --
** Bill Houle                       bhoule@se-sd.SanDiego.NCR.COM
** NCR SE-San Diego                 (619) 693-5593
*/

#include <stdio.h>
#include <string.h>

/*#define DEBUG	"/bin/cat"		/* comment this out for installation */
#define	BINMAIL	"/bin/mail"
#define	TRUE	1
#define	FALSE	0

char	line[255], env[255];
void	exit(), perror();

void syserr(str)
char *str;
{
	perror(str);
	exit(1);
}

main(argc, argv)
int argc;
char **argv;
{
	int fd[2], from_found=TRUE;

	if (gets(line) != NULL) {			/* read first line    *
/
		strcpy(env, "LOGNAME=");
		if (strncmp(line, "From ", 5) == 0) {	/* From_ line?        *
/
			(void) strtok(line, " \t\n\r");	/* get address token  *
/
			strcat(env, strtok(NULL, " \t\n\r"));
		}
		else {
			from_found=FALSE;		/* no From_ line      *
/
			strcat(env, cuserid(NULL));	/* default to user-id *
/
		}
		(void) putenv(env);			/* change $LOGNAME    *
/
	}

	if (pipe(fd) < 0) syserr("pipe");		/* prepare pipe       *
/
	switch (fork()) {				/* fork to /bin/mail  *
/
	case -1:
		syserr("fork to /bin/mail");
	case 0:
		if (close(0) < 0)			/* close stdin        *
/
			syserr("close child stdin");
		if (dup(fd[0]) != 0)			/* stdin from pipe    *
/
			syserr("dup pipe to stdin");
		if (close(fd[0]) < 0 || close(fd[1]) < 0)
			syserr("close child pipe");
#ifdef DEBUG
		(void) fprintf(stderr, "[set %s and exec %s]\n", env, BINMAIL);
		(void) fprintf(stderr, "Debugging through %s.\n", DEBUG);
		(void) execl(DEBUG, DEBUG, 0);
		(void) fprintf(stderr, "Cannot exec %s from %s.\n",
		  DEBUG, argv[0]);
		exit(0);
#else
		(void) execv(BINMAIL, argv);
		(void) fprintf(stderr, "Cannot exec %s from %s.\n",
		  BINMAIL, argv[0]);
		exit(1);
#endif
	}

	if (close(1) < 0)				/* close stdout       *
/
		syserr("close parent stdout");
	if (dup(fd[1]) != 1)				/* stdout to pipe     *
/
		syserr("dup pipe to stdout");
	if (close(fd[0]) < 0 || close(fd[1]) < 0)
		syserr("close parent pipe");

	if (!from_found) (void) puts(line);		/* 1st line not From_ *
/
	while (gets(line) != NULL)			/* send rest of msg   *
/
		(void) puts(line);
	exit(0);
	return(0);					/* make lint happy    *
/
}