andy@icom.UUCP (Andrew H. Marrinson) (09/05/86)
This is the program I use to do the header cracking for smail. Smail as
written relies on sendmail for this. I do not run sendmail, nor would I
want to. This program gives me the small part of sendmail that I do want.
Note that I have not read the RFC's involved. My knowledge of headers was
gleaned from such semi-reliable places as the Usenet documentation.
Anyway, the README describes how to set it up on your system. Hope someone
finds this useful. I would be interested in hearing about any
hacks/changes/improvements.
--------------------- cut here, run through sh --------------------------
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
# README
# cmail.c
# This archive created: Fri Sep 5 10:21:27 1986
export PATH; PATH=/bin:$PATH
echo shar: extracting "'README'" '(1595 characters)'
if test -f 'README'
then
echo shar: will not over-write existing file "'README'"
else
sed 's/^ X//' << \SHAR_EOF > 'README'
XThis little program reads a mail message from the standard input and parses
Xthe headers as follows:
X
X To, Cc - parsed into command line arguments for smail, and copied
X to the output
X Bcc - parsed into command line arguments, not copied to the output
X From - copied to standard output
X Message-ID, Date, Sender - deleted from the message
X
XAnything else that looks like a header is copied to the output without being
Xprocessed in any way. Cmail recognizes the end of the headers when it sees
Xa completely blank line. It also assumes that anything that doesn't look
Xlike a header (i.e., that doesn't match the RE '^[^ \t]*:' ends the headers,
Xbut it prints a warning in this case. Before copying the first non-header
Xline, it outputs Message-ID, and Date headers. If a From header was found
Xin the input it outputs a Sender header, otherwise it outputs a From header.
X
XTo install this program on your system:
X
X1) Edit the SMAIL, FULLHOSTNAME, and HOSTDOMAIN defines near the beginning
X of the program appropriately for your system.
X
X2) Compile with "cc -O -o cmail cmail.c".
X
X3) Copy it to an executable directory (e.g. /usr/local/bin or /usr/bin).
X
XThe program was written for use with a hacked up Gosling mailer. This
Xmailer is not available as it is an embarrasment to mankind, and includes
Xcopyrighted code from the emacs distribution. It can also be used from vi
X(I am told) using the !! command.
X
XGood Luck and Have Fun!
X
X andy@icom.UUCP
X Or for those of Andrew H. Marrinson
X you who wish to ICOM Systems, Inc.
X play it the hard Arlington Heights, IL 60005
X way: ihnp4!icom!andy
SHAR_EOF
if test 1595 -ne "`wc -c < 'README'`"
then
echo shar: error transmitting "'README'" '(should have been 1595 characters)'
fi
fi # end of overwriting check
echo shar: extracting "'cmail.c'" '(10064 characters)'
if test -f 'cmail.c'
then
echo shar: will not over-write existing file "'cmail.c'"
else
sed 's/^ X//' << \SHAR_EOF > 'cmail.c'
X/* system include files */
X#include <stdio.h>
X#include <pwd.h>
X#include <sys/utsname.h>
X#include <string.h>
X#include <time.h>
X#include <fcntl.h>
X#include <ctype.h>
X
X
X/* local parameters */
X#ifdef DEBUG
X#define SMAIL "../smail"
X#else
X#define SMAIL "/bin/smail"
X#endif
X#define FULLHOSTNAME "Icom Systems, Inc."
X#define HOSTDOMAIN "UUCP"
X
X
X/* external routines */
Xchar *mktemp();
Xint umask();
Xint getpid();
Xint getuid();
Xstruct passwd *getpwuid();
Xint uname();
Xvoid endpwent();
Xlong time();
Xstruct tm *gmtime();
Xchar *malloc();
Xvoid free();
Xvoid exit();
X
X
X/* global variables */
Xchar *tfn = "/tmp/cmXXXXXX"; /* temporary file name (filled in with
X mktemp(3)) */
XFILE *ofile; /* temp. file in which the mail is stored */
Xint pid; /* process id for use in message-id header */
Xchar *name; /* user name for use in from or sender header
X */
Xchar *fname; /* full user name for use in from or sender
X header */
Xchar *hname; /* host name for use in from or sender header
X */
Xchar *hdom; /* host domain for use in from or sender
X header */
Xchar *fhname; /* full host name for use in from or sender
X header */
Xlong now; /* current date and time (numeric) */
Xstruct tm *nows; /* broken out date and time (GMT) for use in
X date header */
Xint forged = 0; /* this flag will be set if from line is
X encountered in the input */
Xchar *cvec[100] = { /* command to be executed, addresses will */
X SMAIL /* be filled in as they are parsed */
X#ifdef DEBUG
X , "-d" /* run smail in debugging mode */
X#endif
X};
X#ifdef DEBUG
Xint nextvec = 2; /* next location in cvec to be filled */
X#else
Xint nextvec = 1; /* next location in cvec to be filled */
X#endif
X
X
X/* forward declarations */
Xint hparse(); /* parse header & determine type */
Xvoid address(); /* parse and save addresses */
Xvoid doheads(); /* print system supplied headers */
Xvoid error(); /* print error message and exit */
Xvoid warn(); /* print warning message */
X
X
Xmain()
X
X{
X int cmask; /* holds umask while we change it */
X int uid; /* user id field to find password entry */
X struct passwd *pwent; /* password entry, for info to use in
X from or sender header */
X struct utsname uts; /* uname structure to get host name */
X int inhead; /* flag, non-zero if still in headers */
X static char buf[4096]; /* line buffer */
X char *field; /* points to field parsed by hparse (just
X past :[ \t]+) */
X#ifdef DEBUG
X char **cpp; /* used to display the command used */
X#endif
X
X /* create the temporary file */
X (void) mktemp(tfn); /* create temporary file name */
X cmask = umask(0077); /* no one else should be able to read it */
X ofile = fopen(tfn, "w"); /* open it for writing */
X (void) umask(cmask); /* restore old mask */
X
X /* get relevant system info */
X pid = getpid(); /* process id for use in the message id */
X uid = getuid(); /* now get the users name */
X if ((pwent = getpwuid(uid)) == NULL)
X error("unable to determine user name");
X endpwent(); /* close password file */
X name = pwent->pw_name; /* save user name */
X fname = pwent->pw_gecos; /* this may be his long name */
X if (*fname == '\0' || strpbrk(fname, "()="))
X fname = name; /* use short name, if it is empty or gecos */
X (void) uname(&uts); /* get uname structure */
X hname = uts.nodename; /* save hostname */
X fhname = FULLHOSTNAME; /* sadly, there is no system location */
X hdom = HOSTDOMAIN; /* for these two fields */
X (void) time(&now); /* get current numeric time for mesg id */
X nows = gmtime(&now); /* get structure with greenwich mean time */
X
X /* copy the mail to the temp. file, fixing up the headers
X and keeping track of the addresses */
X inhead = 1; /* yes, we are reading headers now */
X while (fgets(buf, sizeof(buf), stdin)) {
X
X /* handle headers */
X if (inhead) {
X switch (hparse(buf, &field)) {
X case 'T': /* To: and Cc: fields, parse addresses */
X case 'C': /* and copy to output */
X address(field);
X break;
X case 'B': /* Bcc: field, parse addr., do not copy */
X address(field);
X continue; /* skip the copy at end of while */
X case 'F': /* From:, set forged flag & copy */
X ++forged;
X break;
X case 'M': /* Message-ID:, Date:, Sender:, must */
X case 'D': /* never bes specified by the user */
X case 'S': /* ignore them */
X continue;
X case 'X': /* any other header will be copied */
X break;
X case '?': /* This is returned when something that
X doesnt look like a header is found. We
X print a warning, and output a newline to
X seperate the headers from what we assume
X is the body */
X warn("non-header line in header, end of headers assumed");
X inhead = 0; /* mark it, and copy the line */
X doheads(); /* generate the remaining headers */
X putc('\n', ofile);
X break; /* print the first body line after the extra
X newline */
X case 'Z': /* we have found the end of the headers */
X inhead = 0; /* mark it, and copy the line */
X doheads(); /* generate the remaining headers */
X break; /* don't forget to print the first body line */
X }
X }
X /* copy line to temp. file */
X fputs(buf, ofile);
X }
X
X /* pass the resulting file to smail */
X fclose(ofile); /* close it */
X if (nextvec == 1) /* if no addresses, give error mesg. */
X error("no addresses specified");
X#ifdef DEBUG
X cpp = cvec; /* echo the command we will use */
X do
X printf("%s%s", *cpp ? *cpp : "\n", *cpp ? " " : "-------\n");
X while (*cpp++);
X#endif
X close(0); /* close std. input, so we can redirect */
X (void) open(tfn, O_RDONLY); /* now temp. file is standard input */
X (void) unlink(tfn); /* unlink, file will be removed when closed */
X cvec[nextvec] = NULL; /* finish off the argv list for exec */
X execv(cvec[0], cvec); /* exec smail, with temp. file as stdin */
X error("unable to exec smail");
X /* NOTREACHED */
X}
X
X
Xint hparse(line, field)
X
Xchar *line;
Xchar **field;
X
X{
X static char lasthead = '?'; /* last header seen, return assumed end of
X header if first line starts with white */
X static struct ht { /* table of recognized headers */
X int hlen; /* length of header including ':' */
X char *hstr; /* header string, e.g. "From:" */
X } htable[] = {
X 3, "To:",
X 3, "Cc:",
X 4, "Bcc:",
X 5, "From:",
X 11, "Message-ID:",
X 5, "Date:",
X 7, "Sender:",
X 0, NULL
X };
X struct ht *p; /* pointer to cycle through the above table */
X char *cp; /* aux. char pointer for guessing about
X unknown headers */
X
X /* if line starts with white space, return last header type */
X if (*line == ' ' || *line == '\t')
X return lasthead;
X
X /* cycle through table looking for a match */
X for (p = htable; p->hlen != 0; ++p) {
X if (strncmp(p->hstr, line, p->hlen) != 0)
X continue; /* no match, try next */
X
X /* we have matched headers, return a pointer to first non-space
X past ':' in field */
X line += p->hlen; /* point past ':' */
X *field = line+strspn(line, " \t");
X return lasthead = *p->hstr;
X }
X
X /* if no match was found, see if it looks like a header, note that
X we need not set field in this case */
X if ((cp = strpbrk(line, " \t:")) != NULL && *cp == ':')
X return lasthead = 'X'; /* yep, it appears to be a header */
X
X /* otherwise, return whether or not we are sure this is end of headers */
X return (*line == '\n') ? 'Z' : '?';
X}
X
X
Xvoid address(alist)
X
Xchar *alist;
X
X{
X char *p; /* pointer used to cycle through addresses */
X char *cp; /* auxilliary pointer used to further parse
X the indivual addresses */
X
X /* make a copy of the address list so we can split it with strtok(3) */
X p = malloc((unsigned) (strlen(alist)+1));
X alist = strcpy(p, alist); /* copy the address list */
X
X /* cycle through the list, splitting on commas */
X for (p = strtok(alist, ",\n"); p != NULL; p = strtok(NULL, ",\n")) {
X
X /* addresses take two general forms:
X addr [ (comment) ], and
X [ comment ] < addr >
X The following code deletes the comments. It makes the
X simplifying assumption that there will be nothing valid
X following a '(' even outside the corresponding ')' */
X if ((cp = strchr(p, '(')) != NULL)
X *cp = '\0'; /* ignore comment */
X else if ((cp = strchr(p, '<')) != NULL) {
X p = cp+1; /* change starting point to after '<' */
X if ((cp = strchr(p, '>')) != NULL)
X *cp = '\0'; /* change end to before '>' */
X }
X
X /* now strip leading and trailing blanks, and turn all others into
X '.'s */
X while (isspace(*p))
X ++p; /* skip leading space */
X for (cp = p; *cp != '\0'; ++cp) {
X if (isspace(*cp))
X *cp = '.'; /* convert spaces to dots */
X }
X while (*--cp == '.') ; /* back up to first no-dot */
X *++cp = '\0'; /* and there is the end of the address */
X
X /* now make a copy of the string using malloc and store it in
X list */
X if ((cp = malloc((unsigned) (cp-p+1))) == NULL)
X error("out of memory");
X cvec[nextvec++] = strcpy(cp, p);
X }
X free(alist); /* return copied alist to heap */
X}
X
X
Xvoid doheads()
X
X{
X static char *month[] = {
X "Jan", "Feb", "Mar", "Apr", "May", "Jun",
X "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
X };
X static char *day[] = {
X "Sun", "Mon", "Tue", "Wed",
X "Thu", "Fri", "Sat"
X };
X
X /* print the from or sender header (depending on the forged flag) */
X fprintf(ofile, "%s: %s@%s.%s (%s at %s)\n", forged ? "Sender" : "From",
X name, hname, hdom, fname, fhname);
X
X /* print the date header */
X fprintf(ofile, "Date: %.2d %s %.2d %.2d:%.2d:%.2d GMT (%s)\n",
X nows->tm_mday, month[nows->tm_mon], nows->tm_year%100,
X nows->tm_hour, nows->tm_min, nows->tm_sec,
X day[nows->tm_wday]);
X
X /* print the message ID header */
X fprintf(ofile, "Message-ID: <%lu%.5u@%s.%s>\n", now, pid, hname, hdom);
X}
X
X
Xvoid error(s)
X
Xchar *s;
X
X{
X fprintf(stderr, "cmail: %s\n", s);
X (void) unlink(tfn); /* unlink the temporary file */
X exit(1);
X}
X
X
Xvoid warn(s)
X
Xchar *s;
X
X{
X fprintf(stderr, "cmail: warning: %s\n", s);
X}
SHAR_EOF
if test 10064 -ne "`wc -c < 'cmail.c'`"
then
echo shar: error transmitting "'cmail.c'" '(should have been 10064 characters)'
fi
fi # end of overwriting check
# End of shell archive
exit 0
--
andy@icom.UUCP
Or for those of Andrew H. Marrinson
you who wish to ICOM Systems, Inc.
play it the hard Arlington Heights, IL 60005
way: ihnp4!icom!andy