usr/src/usr.bin/vacation/vacation.c

# include <sys/types.h>
# include <pwd.h>
# include <stdio.h>
# include <sysexits.h>
# include <ctype.h>

static char     SccsId[] =      "@(#)vacation.c 4.2             %G%";

/*
**  VACATION -- return a message to the sender when on vacation.
**
**      This program could be invoked as a message receiver
**      when someone is on vacation.  It returns a message
**      specified by the user to whoever sent the mail, taking
**      care not to return a message too often to prevent
**      "I am on vacation" loops.
**
**      Positional Parameters:
**              the user to collect the vacation message from.
**
**      Flag Parameters:
**              -I      initialize the database.
**
**      Side Effects:
**              A message is sent back to the sender.
**
**      Author:
**              Eric Allman
**              UCB/INGRES
*/

typedef int     bool;

# define TRUE           1
# define FALSE          0

# define MAXLINE        256     /* max size of a line */
# define MAXNAME        128     /* max size of one name */

# define ONEWEEK        (60L*60L*24L*7L)

time_t  Timeout = ONEWEEK;      /* timeout between notices per user */

struct dbrec
{
        long    sentdate;
};

typedef struct
{
        char    *dptr;
        int     dsize;
} DATUM;

extern DATUM fetch();

main(argc, argv)
        char **argv;
{
        char *from;
        register char *p;
        struct passwd *pw;
        char *homedir;
        char *myname;
        char buf[MAXLINE];
        extern struct passwd *getpwnam();
        extern char *newstr();
        extern char *getfrom();
        extern bool knows();
        extern time_t convtime();

        /* process arguments */
        while (--argc > 0 && (p = *++argv) != NULL && *p == '-')
        {
                switch (*++p)
                {
                  case 'I':     /* initialize */
                        initialize();
                        exit(EX_OK);

                  default:
                        usrerr("Unknown flag -%s", p);
                        exit(EX_USAGE);
                }
        }

        /* verify recipient argument */
        if (argc != 1)
        {
                usrerr("Usage: vacation username (or) vacation -I");
                exit(EX_USAGE);
        }

        myname = p;

        /* find user's home directory */
        pw = getpwnam(myname);
        if (pw == NULL)
        {
                usrerr("Unknown user %s", myname);
                exit(EX_NOUSER);
        }
        homedir = newstr(pw->pw_dir);
        (void) strcpy(buf, homedir);
        (void) strcat(buf, "/.vacation");
        dbminit(buf);

        /* read message from standard input (just from line) */
        from = getfrom();

        /* check if this person is already informed */
        if (!knows(from))
        {
                /* mark this person as knowing */
                setknows(from);

                /* send the message back */
                (void) strcpy(buf, homedir);
                (void) strcat(buf, "/.vacation.msg");
                sendmessage(buf, from, myname);
                /* never returns */
        }
        exit (EX_OK);
}
\f/*
**  GETFROM -- read message from standard input and return sender
**
**      Parameters:
**              none.
**
**      Returns:
**              pointer to the sender address.
**
**      Side Effects:
**              Reads first line from standard input.
*/

char *
getfrom()
{
        static char line[MAXLINE];
        register char *p;
        extern char *index();

        /* read the from line */
        if (fgets(line, sizeof line, stdin) == NULL ||
            strncmp(line, "From ", 5) != NULL)
        {
                usrerr("No initial From line");
                exit(EX_USAGE);
        }

        /* find the end of the sender address and terminate it */
        p = index(&line[5], ' ');
        if (p == NULL)
        {
                usrerr("Funny From line '%s'", line);
                exit(EX_USAGE);
        }
        *p = '\0';

        /* return the sender address */
        return (&line[5]);
}
\f/*
**  KNOWS -- predicate telling if user has already been informed.
**
**      Parameters:
**              user -- the user who sent this message.
**
**      Returns:
**              TRUE if 'user' has already been informed that the
**                      recipient is on vacation.
**              FALSE otherwise.
**
**      Side Effects:
**              none.
*/

bool
knows(user)
        char *user;
{
        DATUM k, d;
        long now;

        time(&now);
        k.dptr = user;
        k.dsize = strlen(user) + 1;
        d = fetch(k);
        if (d.dptr == NULL || ((struct dbrec *) d.dptr)->sentdate + Timeout < now)
                return (FALSE);
        return (TRUE);
}
\f/*
**  SETKNOWS -- set that this user knows about the vacation.
**
**      Parameters:
**              user -- the user who should be marked.
**
**      Returns:
**              none.
**
**      Side Effects:
**              The dbm file is updated as appropriate.
*/

setknows(user)
        char *user;
{
        DATUM k, d;
        struct dbrec xrec;

        k.dptr = user;
        k.dsize = strlen(user) + 1;
        time(&xrec.sentdate);
        d.dptr = (char *) &xrec;
        d.dsize = sizeof xrec;
        store(k, d);
}
\f/*
**  SENDMESSAGE -- send a message to a particular user.
**
**      Parameters:
**              msgf -- filename containing the message.
**              user -- user who should receive it.
**
**      Returns:
**              none.
**
**      Side Effects:
**              sends mail to 'user' using /usr/lib/sendmail.
*/

sendmessage(msgf, user, myname)
        char *msgf;
        char *user;
        char *myname;
{
        FILE *f;

        /* find the message to send */
        f = freopen(msgf, "r", stdin);
        if (f == NULL)
        {
                f = freopen("/usr/lib/vacation.def", "r", stdin);
                if (f == NULL)
                        syserr("No message to send");
        }

        execl("/usr/lib/sendmail", "sendmail", "-f", myname, user, NULL);
        syserr("Cannot exec /usr/lib/sendmail");
}
\f/*
**  INITIALIZE -- initialize the database before leaving for vacation
**
**      Parameters:
**              none.
**
**      Returns:
**              none.
**
**      Side Effects:
**              Initializes the files .vacation.{pag,dir} in the
**              caller's home directory.
*/

initialize()
{
        char *homedir;
        char buf[MAXLINE];
        extern char *getenv();

        setgid(getgid());
        setuid(getuid());
        homedir = getenv("HOME");
        if (homedir == NULL)
                syserr("No home!");
        (void) strcpy(buf, homedir);
        (void) strcat(buf, "/.vacation.dir");
        if (close(creat(buf, 0644)) < 0)
                syserr("Cannot create %s", buf);
        (void) strcpy(buf, homedir);
        (void) strcat(buf, "/.vacation.pag");
        if (close(creat(buf, 0644)) < 0)
                syserr("Cannot create %s", buf);
}
\f/*
**  USRERR -- print user error
**
**      Parameters:
**              f -- format.
**              p -- first parameter.
**
**      Returns:
**              none.
**
**      Side Effects:
**              none.
*/

usrerr(f, p)
        char *f;
        char *p;
{
        fprintf(stderr, "vacation: ");
        _doprnt(f, &p, stderr);
        fprintf(stderr, "\n");
}
\f/*
**  SYSERR -- print system error
**
**      Parameters:
**              f -- format.
**              p -- first parameter.
**
**      Returns:
**              none.
**
**      Side Effects:
**              none.
*/

syserr(f, p)
        char *f;
        char *p;
{
        fprintf(stderr, "vacation: ");
        _doprnt(f, &p, stderr);
        fprintf(stderr, "\n");
        exit(EX_USAGE);
}
\f/*
**  NEWSTR -- copy a string
**
**      Parameters:
**              s -- the string to copy.
**
**      Returns:
**              A copy of the string.
**
**      Side Effects:
**              none.
*/

char *
newstr(s)
        char *s;
{
        char *p;
        extern char *malloc();

        p = malloc(strlen(s) + 1);
        if (p == NULL)
        {
                syserr("newstr: cannot alloc memory");
                exit(EX_OSERR);
        }
        strcpy(p, s);
        return (p);
}