⟦bc9a2d770⟧

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/* system include files */
#include <stdio.h>
#include <pwd.h>
#include <sys/utsname.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <ctype.h>


/* local parameters */
#ifdef DEBUG
#define SMAIL "../smail"
#else
#define SMAIL "/bin/smail"
#endif
#define FULLHOSTNAME "Icom Systems, Inc."
#define HOSTDOMAIN "UUCP"


/* external routines */
char *mktemp();
int umask();
int getpid();
int getuid();
struct passwd *getpwuid();
int uname();
void endpwent();
long time();
struct tm *gmtime();
char *malloc();
void free();
void exit();


/* global variables */
char *tfn = "/tmp/cmXXXXXX";	/* temporary file name (filled in with
				   mktemp(3)) */
FILE *ofile;			/* temp. file in which the mail is stored */
int pid;			/* process id for use in message-id header */
char *name;			/* user name for use in from or sender header
				   */
char *fname;			/* full user name for use in from or sender
				   header */
char *hname;			/* host name for use in from or sender header
				   */
char *hdom;			/* host domain for use in from or sender
				   header */
char *fhname;			/* full host name for use in from or sender
				   header */
long now;			/* current date and time (numeric) */
struct tm *nows;		/* broken out date and time (GMT) for use in
				   date header */
int forged = 0;			/* this flag will be set if from line is
				   encountered in the input */
char *cvec[100] = {		/* command to be executed, addresses will */
    SMAIL			/* be filled in as they are parsed */
#ifdef DEBUG
    , "-d"			/* run smail in debugging mode */
#endif
};
#ifdef DEBUG
int nextvec = 2;		/* next location in cvec to be filled */
#else
int nextvec = 1;		/* next location in cvec to be filled */
#endif


/* forward declarations */
int hparse();			/* parse header & determine type */
void address();			/* parse and save addresses */
void doheads();			/* print system supplied headers */
void error();			/* print error message and exit */
void warn();			/* print warning message */


main()

{
    int cmask;			/* holds umask while we change it */
    int uid;			/* user id field to find password entry */
    struct passwd *pwent;	/* password entry, for info to use in
				   from or sender header */
    struct utsname uts;		/* uname structure to get host name */
    int inhead;			/* flag, non-zero if still in headers */
    static char buf[4096];	/* line buffer */
    char *field;		/* points to field parsed by hparse (just
				   past :[ \t]+) */
#ifdef DEBUG
    char **cpp;			/* used to display the command used */
#endif

    /* create the temporary file */
    (void) mktemp(tfn);		/* create temporary file name */
    cmask = umask(0077);	/* no one else should be able to read it */
    ofile = fopen(tfn, "w");	/* open it for writing */
    (void) umask(cmask);	/* restore old mask */

    /* get relevant system info */
    pid = getpid();		/* process id for use in the message id */
    uid = getuid();		/* now get the users name */
    if ((pwent = getpwuid(uid)) == NULL)
	error("unable to determine user name");
    endpwent();			/* close password file */
    name = pwent->pw_name;	/* save user name */
    fname = pwent->pw_gecos;	/* this may be his long name */
    if (*fname == '\0' || strpbrk(fname, "()="))
	fname = name;		/* use short name, if it is empty or gecos */
    (void) uname(&uts);		/* get uname structure */
    hname = uts.nodename;	/* save hostname */
    fhname = FULLHOSTNAME;	/* sadly, there is no system location */
    hdom = HOSTDOMAIN;		/* for these two fields */
    (void) time(&now);		/* get current numeric time for mesg id */
    nows = gmtime(&now);	/* get structure with greenwich mean time */

    /* copy the mail to the temp. file, fixing up the headers
	and keeping track of the addresses */
    inhead = 1;			/* yes, we are reading headers now */
    while (fgets(buf, sizeof(buf), stdin)) {

	/* handle headers */
	if (inhead) {
	    switch (hparse(buf, &field)) {
		case 'T':	/* To: and Cc: fields, parse addresses */
		case 'C':	/* and copy to output */
		    address(field);
		    break;
		case 'B':	/* Bcc: field, parse addr., do not copy */
		    address(field);
		    continue;	/* skip the copy at end of while */
		case 'F':	/* From:, set forged flag & copy */
		    ++forged;
		    break;
		case 'M':	/* Message-ID:, Date:, Sender:, must */
		case 'D':	/* never bes specified by the user */
		case 'S':	/* ignore them */
		    continue;
		case 'X':	/* any other header will be copied */
		    break;
		case '?':	/* This is returned when something that
				   doesnt look like a header is found. We
				   print a warning, and output a newline to
				   seperate the headers from what we assume
				   is the body */
		    warn("non-header line in header, end of headers assumed");
		    inhead = 0;	/* mark it, and copy the line */
		    doheads();	/* generate the remaining headers */
		    putc('\n', ofile);
		    break;	/* print the first body line after the extra
				   newline */
		case 'Z':	/* we have found the end of the headers */
		    inhead = 0;	/* mark it, and copy the line */
		    doheads();	/* generate the remaining headers */
		    break;	/* don't forget to print the first body line */
	    }
	}
	/* copy line to temp. file */
	fputs(buf, ofile);
    }

    /* pass the resulting file to smail */
    fclose(ofile);		/* close it */
    if (nextvec == 1)		/* if no addresses, give error mesg. */
	error("no addresses specified");
#ifdef DEBUG
    cpp = cvec;			/* echo the command we will use */
    do
	printf("%s%s", *cpp ? *cpp : "\n", *cpp ? " " : "-------\n");
    while (*cpp++);
#endif
    close(0);			/* close std. input, so we can redirect */
    (void) open(tfn, O_RDONLY);	/* now temp. file is standard input */
    (void) unlink(tfn);		/* unlink, file will be removed when closed */
    cvec[nextvec] = NULL;	/* finish off the argv list for exec */
    execv(cvec[0], cvec);	/* exec smail, with temp. file as stdin */
    error("unable to exec smail");
    /* NOTREACHED */
}


int hparse(line, field)

char *line;
char **field;

{
    static char lasthead = '?';	/* last header seen, return assumed end of
				   header if first line starts with white */
    static struct ht {		/* table of recognized headers */
	int hlen;		/* length of header including ':' */
	char *hstr;		/* header string, e.g. "From:" */
    } htable[] = {
	 3, "To:",
	 3, "Cc:",
	 4, "Bcc:",
	 5, "From:",
	11, "Message-ID:",
	 5, "Date:",
	 7, "Sender:",
	 0, NULL
    };
    struct ht *p;		/* pointer to cycle through the above table */
    char *cp;			/* aux. char pointer for guessing about
				   unknown headers */

    /* if line starts with white space, return last header type */
    if (*line == ' ' || *line == '\t') {
	/* of course it would be nice if we set field */
	*field = line+strspn(line, " \t");
	return lasthead;
    }

    /* cycle through table looking for a match */
    for (p = htable; p->hlen != 0; ++p) {
	if (strncmp(p->hstr, line, p->hlen) != 0)
	    continue;		/* no match, try next */

	/* we have matched headers, return a pointer to first non-space
	   past ':' in field */
	line += p->hlen;	/* point past ':' */
	*field = line+strspn(line, " \t");
	return lasthead = *p->hstr;
    }

    /* if no match was found, see if it looks like a header, note that
       we need not set field in this case */
    if ((cp = strpbrk(line, " \t:")) != NULL && *cp == ':')
	return lasthead = 'X';	/* yep, it appears to be a header */

    /* otherwise, return whether or not we are sure this is end of headers */
    return (*line == '\n') ? 'Z' : '?';
}


void address(alist)

char *alist;

{
    char *p;			/* pointer used to cycle through addresses */
    char *cp;			/* auxilliary pointer used to further parse
				   the indivual addresses */
    int incmnt;			/* variable used to eliminate comments */

    /* make a copy of the address list so we can split it with strtok(3) */
    /* *SIGH* ok, lets try removing the comments FIRST, since they might
	contain commas (stupid) */
    p = malloc((unsigned) (strlen(alist)+1));
    incmnt = 0;
    for (cp = p; *alist != '\0'; ++alist) {
	if (incmnt) {
	    if (*alist == ')')
		incmnt = 0;	/* the comment is over */
	} else if (*alist == '(')
	    incmnt = 1;		/* we have started a comment */
	else
	    *cp++ = *alist;	/* copy everything not in a comment */
    }
    *cp = '\0';			/* terminate the string */
    alist = p;			/* ok boss, that ought to fix the bastard! */

    /* cycle through the list, splitting on commas */
    for (p = strtok(alist, ",\n"); p != NULL; p = strtok(NULL, ",\n")) {

	/* addresses take two general forms:
		addr [ (comment) ], and
		[ comment ] < addr >
	   The code above deleted the first type of comment, the code
	   below handles the second form.  Note that no commas may appear
	   in the second form, and that the parenthesis in the first
	   form do not nest.  Hopefully these will not bite me as the
	   commas inside parens did. */
	if ((cp = strchr(p, '<')) != NULL) {
	    p = cp+1;		/* change starting point to after '<' */
	    if ((cp = strchr(p, '>')) != NULL)
		*cp = '\0';	/* change end to before '>' */
	}

	/* now strip leading and trailing blanks, and turn all others into
	   '.'s */
	while (isspace(*p))
	    ++p;		/* skip leading space */
	for (cp = p; *cp != '\0'; ++cp) {
	    if (isspace(*cp))
		*cp = '.';	/* convert spaces to dots */
	}
	while (*--cp == '.') ;	/* back up to first no-dot */
	*++cp = '\0';		/* and there is the end of the address */

	/* now make a copy of the string using malloc and store it in
	   list */
	if ((cp = malloc((unsigned) (cp-p+1))) == NULL)
	    error("out of memory");
	cvec[nextvec++] = strcpy(cp, p);
    }
    free(alist);		/* return copied alist to heap */
}


void doheads()

{
    static char *month[] = {
	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
    };
    static char *day[] = {
	"Sun", "Mon", "Tue", "Wed",
	"Thu", "Fri", "Sat"
    };

    /* print the from or sender header (depending on the forged flag) */
    fprintf(ofile, "%s: %s@%s.%s (%s at %s)\n", forged ? "Sender" : "From",
		name, hname, hdom, fname, fhname);

    /* print the date header */
    fprintf(ofile, "Date: %.2d %s %.2d %.2d:%.2d:%.2d GMT (%s)\n",
		nows->tm_mday, month[nows->tm_mon], nows->tm_year%100,
		nows->tm_hour, nows->tm_min, nows->tm_sec,
		day[nows->tm_wday]);

    /* print the message ID header */
    fprintf(ofile, "Message-ID: <%lu%.5u@%s.%s>\n", now, pid, hname, hdom);
}


void error(s)

char *s;

{
    fprintf(stderr, "cmail: %s\n", s);
    (void) unlink(tfn);		/* unlink the temporary file */
    exit(1);
}


void warn(s)

char *s;

{
    fprintf(stderr, "cmail: warning: %s\n", s);
}
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