Re: your mail

[nettech () crl com (Joseph W. Stroup)]

This is got to stop now ! Everyone of these I get I will bounce to the 
SENDER!

Joseph Stroup

On Sun, 2 Oct 1994, Tim Newsham wrote:

> #ifndef lint
> static        char sccsid[] = "@(#)mail.c 1.1 90/10/29 SMI; from UCB 4.15 83/04/12";
> #endif
>
> /*
>  * /bin/mail - local delivery
>  */
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <sys/file.h>
>
> #include <ctype.h>
> #include <stdio.h>
> #include <pwd.h>
> #include <utmp.h>
> #include <signal.h>
> #include <setjmp.h>
> #include <sysexits.h>
>
> #define SENDMAIL      "/usr/lib/sendmail"
>
>       /* copylet flags */
> #define REMOTE                1               /* remote mail, add rmtmsg */
> #define ORDINARY      2
> #define ZAP           3               /* zap header and trailing empty line */
> #define       FORWARD         4
>
> #define       LSIZE           256
> #define       MAXLET          300             /* maximum number of letters */
> #define       MAILMODE        0600            /* mode of created mail */
>
> char  line[LSIZE];
> char  resp[LSIZE];
> struct let {
>       long    adr;
>       char    change;
> } let[MAXLET];
> int   nlet    = 0;
> char  lfil[50];
> long  iop, time();
> char  *getenv();
> char  *index();
> char  lettmp[] = "/tmp/maXXXXX";
> char  maildir[] = "/var/spool/mail/";
> char  mailfile[] = "/var/spool/mail/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
> char  dead[] = "dead.letter";
> char  forwmsg[] = " forwarded\n";
> FILE  *tmpf;
> FILE  *malf;
> char  *my_name;
> char  *getlogin();
> int   error;
> int   changed;
> int   forward;
> char  from[] = "From ";
> long  ftell();
> void  delex();
> char  *ctime();
> int   flgf;
> int   flgp;
> int   flge;
> int   flgt;
> int   delflg = 1;
> int   hseqno;
> jmp_buf       sjbuf;
> int   rmail;
>
> main(argc, argv)
> char **argv;
> {
>       register i;
>       struct passwd *pwent;
>
>       mktemp(lettmp);
>       unlink(lettmp);
>       my_name = getlogin();
>       if (my_name == NULL || *my_name == '\0') {
>               pwent = getpwuid(getuid());
>               if (pwent==NULL)
>                       my_name = "???";
>               else
>                       my_name = pwent->pw_name;
>       }
>       else {
>               pwent = getpwnam(my_name);
>               if ( getuid() != pwent->pw_uid) {
>                       pwent = getpwuid(getuid());
>                       my_name = pwent->pw_name;
>               }
>       }
>       if (setjmp(sjbuf))
>               done();
>       for (i=SIGHUP; i<=SIGTERM; i++)
>               setsig(i, delex);
>       tmpf = fopen(lettmp, "w+r");
>       if (tmpf == NULL)
>               panic("mail: %s: cannot open for writing", lettmp);
>       /*
>        * This protects against others reading mail from temp file and
>        * if we exit, the file will be deleted already.
>        */
>       unlink(lettmp);
>       if (argv[0][0] == 'r')
>               rmail++;
>       if (argv[0][0] != 'r' &&        /* no favors for rmail*/
>          (argc == 1 || argv[1][0] == '-' && !any(argv[1][1], "hdt")
>                       && (argv[argc-1][0] == '-' || argv[argc-2][1] == 'f')))
>                                       /* -r can be an option in both
>                                        * cases. If last arg is an option
>                                        * or it's an argument to -f
>                                        * call printmail; otherwise (it's
>                                        * a user name), call bulkmail.
>                                        */
>               printmail(argc, argv);
>       else
>               bulkmail(argc, argv);
>       done();
>       /* NOTREACHED */
> }
>
> setsig(i, f)
> int i;
> void (*f)();
> {
>       if (signal(i, SIG_IGN) != SIG_IGN)
>               signal(i, f);
> }
>
> any(c, str)
>       register int c;
>       register char *str;
> {
>
>       while (*str)
>               if (c == *str++)
>                       return(1);
>       return(0);
> }
>
> printmail(argc, argv)
>       char **argv;
> {
>       int flg, i, j, print;
>       char *p, *getarg();
>       struct stat statb;
>
>       setuid(getuid());
>       cat(mailfile, maildir, my_name);
>       for (; argc > 1; argv++, argc--) {
>               if (argv[1][0] != '-')
>                       break;
>               switch (argv[1][1]) {
>
>               case 'p':
>                       flgp++;
>                       /* fall thru... */
>               case 'q':
>                       delflg = 0;
>                       break;
>
>               case 'f':
>                       if (argv[1][2] == '\0') {
>                               if (argc >= 3) {
>                                       strcpy(mailfile, argv[2]);
>                                       argv++, argc--;
>                               }
>                       }
>                       else    
>                               strcpy(mailfile, &argv[1][2]);
>                       break;
>
>               case 'r':
>                       forward = 1;
>                       break;
>
>               case 'e':
>                       flge++;
>                       break;
>
>               default:
>                       panic("unknown option %c", argv[1][1]);
>                       /*NOTREACHED*/
>               }
>       }
>       malf = fopen(mailfile, "r");
>       if (malf == NULL) {
>               if (!flge) {
>                       printf("No mail.\n");
>                       return;
>               }
>               else {
>                       fclose(tmpf);
>                       error = 1;
>                       done();
>               }       
>       }
>       lock(mailfile);
>       copymt(malf, tmpf);
>       fclose(malf);
>       unlock();
>       
>       /* if e option given, dont' need to go any further */
>       if (flge) {
>               fclose(tmpf);
>               if (nlet)
>                       done();
>               else {
>                       error = 1;
>                       done();
>               }       
>       }
>
>       fseek(tmpf, 0, L_SET);
>
>       changed = 0;
>       print = 1;
>       for (i = 0; i < nlet; ) {
>               j = forward ? i : nlet - i - 1;
>               if (setjmp(sjbuf)) {
>                       print = 0;
>               } else {
>                       if (print)
>                               copylet(j, stdout, ORDINARY);
>                       print = 1;
>               }
>               if (flgp) {
>                       i++;
>                       continue;
>               }
>               setjmp(sjbuf);
>               printf( "? ");
>               fflush(stdout);
>               if (fgets(resp, LSIZE, stdin) == NULL)
>                       break;
>               switch (resp[0]) {
>
>               default:
>                       printf("usage\n");
>               case '?':
>               case '*':
>                       print = 0;
>                       printf("q\tquit\n");
>                       printf("x\texit without changing mail\n");
>                       printf("p\tprint\n");
>                       printf("s[file]\tsave (default mbox)\n");
>                       printf("w[file]\tsame without header\n");
>                       printf("-\tprint previous\n");
>                       printf("d\tdelete\n");
>                       printf("+\tnext (no delete)\n");
>                       printf("m user\tmail to user\n");
>                       printf("! cmd\texecute cmd\n");
>                       break;
>
>               case '+':
>               case 'n':
>               case '\n':
>                       i++;
>                       break;
>               case 'x':
>                       changed = 0;
>               case 'q':
>                       goto donep;
>               case 'p':
>                       break;
>               case '^':
>               case '-':
>                       if (--i < 0)
>                               i = 0;
>                       break;
>               case 'y':
>               case 'w':
>               case 's':
>                       flg = 0;
>                       if (resp[1] != '\n' && resp[1] != ' ') {
>                               printf("illegal\n");
>                               flg++;
>                               print = 0;
>                               continue;
>                       }
>                       if (resp[1] == '\n' || resp[1] == '\0') {
>                               p = getenv("HOME");
>                               if (p != 0)
>                                       cat(resp+1, p, "/mbox");
>                               else
>                                       cat(resp+1, "", "mbox");
>                       }
>                       for (p = resp+1; (p = getarg(lfil, p)) != NULL; ) {
>                               malf = fopen(lfil, "a");
>                               if (malf == NULL) {
>                                       printf("mail: %s: cannot append\n",
>                                           lfil);
>                                       flg++;
>                                       continue;
>                               }
>                               copylet(j, malf, resp[0]=='w'? ZAP: ORDINARY);
>                               fclose(malf);
>                       }
>                       if (flg)
>                               print = 0;
>                       else {
>                               let[j].change = 'd';
>                               changed++;
>                               i++;
>                       }
>                       break;
>               case 'm':
>                       flg = 0;
>                       if (resp[1] == '\n' || resp[1] == '\0') {
>                               i++;
>                               continue;
>                       }
>                       if (resp[1] != ' ') {
>                               printf("invalid command\n");
>                               flg++;
>                               print = 0;
>                               continue;
>                       }
>                       for (p = resp+1; (p = getarg(lfil, p)) != NULL; )
>                               if (!sendmail(j, lfil, my_name))
>                                       /* couldn't send it */
>                                       flg++;
>                       if (flg)
>                               print = 0;
>                       else {
>                               let[j].change = 'd';
>                               changed++;
>                               i++;
>                       }
>                       break;
>               case '!':
>                       system(resp+1);
>                       printf("!\n");
>                       print = 0;
>                       break;
>               case 'd':
>                       let[j].change = 'd';
>                       changed++;
>                       i++;
>                       if (resp[1] == 'q')
>                               goto donep;
>                       break;
>               }
>       }
>    donep:
>       if (changed)
>               copyback();
> }
>
> /* copy temp or whatever back to /var/spool/mail */
> copyback()
> {
>       register i, c;
>       int fd, new = 0, oldmask;
>       struct stat stbuf;
>
> #define       mask(s) (1 << ((s) - 1))
>       oldmask = sigblock(mask(SIGINT)|mask(SIGHUP)|mask(SIGQUIT));
> #undef mask
>       lock(mailfile);
>       fd = open(mailfile, O_RDWR | O_CREAT, MAILMODE);
>       if (fd >= 0) {
>               malf = fdopen(fd, "r+w");
>       }
>       if (fd < 0 || malf == NULL)
>               panic("can't rewrite %s", lfil);
>       fstat(fd, &stbuf);
>       if (stbuf.st_size != let[nlet].adr) {   /* new mail has arrived */
>               fseek(malf, let[nlet].adr, L_SET);
>               fseek(tmpf, let[nlet].adr, L_SET);
>               while ((c = getc(malf)) != EOF)
>                       putc(c, tmpf);
>               let[++nlet].adr = stbuf.st_size;
>               new = 1;
>               fseek(malf, 0, L_SET);
>       }
>       ftruncate(fd, 0);
>       for (i = 0; i < nlet; i++)
>               if (let[i].change != 'd')
>                       copylet(i, malf, ORDINARY);
>       fclose(malf);
>       if (new)
>               printf("New mail has arrived.\n");
>       unlock();
>       sigsetmask(oldmask);
> }
>
> /* copy mail (f1) to temp (f2) */
> copymt(f1, f2)
>       FILE *f1, *f2;
> {
>       long nextadr;
>
>       nlet = nextadr = 0;
>       let[0].adr = 0;
>       while (fgets(line, LSIZE, f1) != NULL) {
>               if (isfrom(line))
>                       let[nlet++].adr = nextadr;
>               nextadr += strlen(line);
>               fputs(line, f2);
>       }
>       let[nlet].adr = nextadr;        /* last plus 1 */
> }
>
> copylet(n, f, type)
>       FILE *f;
> {
>       int ch;
>       long k;
>       char hostname[32];
>
>
>       fseek(tmpf, let[n].adr, L_SET);
>       k = let[n+1].adr - let[n].adr;
>       while (k-- > 1 && (ch = getc(tmpf)) != '\n')
>               if (type != ZAP)
>                       putc(ch, f);
>       switch (type) {
>
>       case REMOTE:
>               gethostname(hostname, sizeof (hostname));
>               fprintf(f, " remote from %s\n", hostname);
>               break;
>
>       case FORWARD:
>               fprintf(f, forwmsg);
>               break;
>
>       case ORDINARY:
>               putc(ch, f);
>               break;
>
>       case ZAP:
>               break;
>
>       default:
>               panic("Bad letter type %d to copylet.", type);
>       }
>       while (k-- > 1) {
>               ch = getc(tmpf);
>               putc(ch, f);
>       }
>       if (type != ZAP || ch != '\n')
>               putc(getc(tmpf), f);
> }
>
> isfrom(lp)
> register char *lp;
> {
>       register char *p;
>
>       for (p = from; *p; )
>               if (*lp++ != *p++)
>                       return(0);
>       return(1);
> }
>
> bulkmail(argc, argv)
> char **argv;
> {
>       int aret;
>       char **args;
>       char truename[100];
>       int first;
>       register char *cp;
>       char *newargv[1000];
>       register char **ap;
>       register char **vp;
>       int dflag;
>       int a_count=0;
>       int gaver=0;
>
>       dflag = 0;
>       if (argc < 1) {
>               fprintf(stderr, "puke\n");
>               return;
>       }
>       for (vp = argv, ap = newargv + 1; (*ap = *vp++) != 0; ap++)
>               if (ap[0][0] == '-' && ap[0][1] == 'd')
>                       dflag++;
>       if (!dflag) {
>               /* give it to sendmail, rah rah! */
>               unlink(lettmp);
>               ap = newargv+1;
>               if (rmail)
>                       *ap-- = "-s";
>               *ap = "-sendmail";
>               setuid(getuid());
>               execv(SENDMAIL, ap);
>               perror(SENDMAIL);
>               exit(EX_UNAVAILABLE);
>       }
>
>       truename[0] = 0;
>       line[0] = '\0';
>
>       /*
>        * When we fall out of this, argv[1] should be first name,
>        * argc should be number of names + 1.
>        */
>
>       while (argc > 1 && *argv[1] == '-') {
>               cp = *++argv;
>               argc--;
>               a_count++;
>               switch (cp[1]) {
>               case 'r':
>                       if (argc <= 1)
>                               usage();
>                       gaver++;
>                       strcpy(truename, argv[1]);
>                       fgets(line, LSIZE, stdin);
>                       if (strncmp("From", line, 4) == 0)
>                               line[0] = '\0';
>                       argv++;
>                       argc--;
>                       break;
>               case 'h':
>                       if (argc <= 1)
>                               usage();
>                       hseqno = atoi(argv[1]);
>                       argv++;
>                       argc--;
>                       break;
>
>               case 't':
>                       flgt++;
>                       break;
>
>               case 'd':
>                       break;
>               
>               default:
>                       usage();
>               }
>       }
>       if (argc <= 1)
>               usage();
>       if (rmail && ((a_count>1) || (a_count==1 && !flgt)))
>               usage();
>       if (gaver == 0)
>               strcpy(truename, my_name);
>
>       time(&iop);
>       fprintf(tmpf, "%s%s %s", from, truename, ctime(&iop));
>
>       /* Copy to list in mail entry? */
>       if (flgt && argc > 0 ) {
>               aret = argc;
>               args = argv;
>               fprintf(tmpf,"To: ");
>               while (--aret > 0)
>                       fprintf(tmpf,"%s ", *++args);
>               fprintf(tmpf,"\n");
>       }
>
>       iop = ftell(tmpf);
>       flgf = first = 1;
>       for (;;) {
>               if (first) {
>                       first = 0;
>                       if (*line == '\0' && fgets(line, LSIZE, stdin) == NULL)
>                               break;
>               } else {
>                       if (fgets(line, LSIZE, stdin) == NULL)
>                               break;
>               }
>               if (*line == '.' && line[1] == '\n' && isatty(fileno(stdin)))
>                       break;
>               if (isfrom(line))
>                       putc('>', tmpf);
>               fputs(line, tmpf);
>               flgf = 0;
>       }
>       putc('\n', tmpf);
>       nlet = 1;
>       let[0].adr = 0;
>       let[1].adr = ftell(tmpf);
>       if (flgf)
>               return;
>       while (--argc > 0)
>               if (!sendmail(0, *++argv, truename))
>                       error++;
>       if (error) {
>               /* Don't return count of errors, return a defined code. */
>               error = EX_UNAVAILABLE;
>
>               /* Also, try to save dead.letter */
>               if (safefile(dead)) {
>                       setuid(getuid());
>                       malf = fopen(dead, "w");
>                       if (malf == NULL) {
>                               printf( "mail: cannot open %s\n", dead);
>                               fclose(tmpf);
>                               return;
>                       }
>                       copylet(0, malf, ZAP);
>                       fclose(malf);
>                       printf( "Mail saved in %s\n", dead);
>               }
>       }
>       fclose(tmpf);
> }
>
> sendrmt(n, name)
> char *name;
> {
>       FILE *rmf, *popen();
>       register char *p;
>       char rsys[64], cmd[64];
>       register pid;
>       int sts;
>
>       for (p=rsys; *name!='!'; *p++ = *name++)
>               if (*name=='\0')
>                       return(0);      /* local address, no '!' */
>       *p = '\0';
>       if (name[1]=='\0') {
>               printf("null name\n");
>               return(0);
>       }
> skip:
>       if ((pid = fork()) == -1) {
>               fprintf(stderr, "mail: can't create proc for remote\n");
>               return(0);
>       }
>       if (pid) {
>               while (wait(&sts) != pid) {
>                       if (wait(&sts)==-1)
>                               return(0);
>               }
>               return(!sts);
>       }
>       setuid(getuid());
>       if (any('!', name+1))
>               sprintf(cmd, "uux - %s!rmail \\(%s\\)", rsys, name+1);
>       else
>               sprintf(cmd, "uux - %s!rmail %s", rsys, name+1);
>       if ((rmf=popen(cmd, "w")) == NULL)
>               exit(1);
>       copylet(n, rmf, REMOTE);
>       exit(pclose(rmf) != 0);
> }
>
> usage()
> {
>
>       fprintf(stderr, "Usage: mail [-r] [-t] [-p] [-q] [-e] [-h seqno] [-f fname] [people] . . .\n");
>       error = EX_USAGE;
>       done();
> }
>
> #include <sys/socket.h>
> #include <netinet/in.h>
>
> notifybiff(msg)
>       char *msg;
> {
>       static struct sockaddr_in addr;
>       static int f = -1;
>
>       if (addr.sin_family == 0) {
>               addr.sin_family = AF_INET;
>               addr.sin_addr.s_addr = INADDR_ANY;
>               addr.sin_port = htons(IPPORT_BIFFUDP);
>       }
>       if (f < 0)
>               f = socket(AF_INET, SOCK_DGRAM, 0);
>       sendto(f, msg, strlen(msg)+1, 0, &addr, sizeof (addr));
> }
>
> sendmail(n, name, fromaddr)
>       int n;
>       char *name;
>       char *fromaddr;
> {
>       char file[256];
>       int fd;
>       struct passwd *pw;
>       char buf[128];
>       int realuser;
>
>       if (*name=='!')
>               name++;
>       if (any('!', name))
>               return (sendrmt(n, name));
>       if ((pw = getpwnam(name)) == NULL) {
>               printf("mail: can't send to %s\n", name);
>               return(0);
>       }
>       cat(file, maildir, name);
>       if (!safefile(file))
>               return(0);
>         /*
>          * Remember the real UID, and temporarily become the target
>          * user in case we are going across NFS
>          */
>       realuser = getuid();
>       setreuid(0,pw->pw_uid);
>       lock(file);
>       fd = open(file, O_WRONLY | O_CREAT, MAILMODE);
>       if (fd >= 0) {
>               flock(fd, LOCK_EX);
>               malf = fdopen(fd, "a");
>       }
>       if (fd < 0 || malf == NULL) {
>               unlock();
>               close(fd);
>               printf("mail: %s: cannot append\n", file);
>               setuid(0);
>               setreuid(realuser,0);
>               return(0);
>       }
>       setuid(0);
>       setreuid(realuser,0);
>       fchown(fd, pw->pw_uid, pw->pw_gid);
>       sprintf(buf, "%s@%d\n", name, ftell(malf)); 
>       copylet(n, malf, ORDINARY);
>       fclose(malf);
>       setreuid(0,pw->pw_uid);
>       unlock();
>       notifybiff(buf);
>       setuid(0);
>       setreuid(realuser,0);
>       return(1);
> }
>
> void
> delex(i)
> {
>       setsig(i, delex);
>       putc('\n', stderr);
>       if (delflg)
>               longjmp(sjbuf, 1);
>       done();
> }
>
> /*
>  * Lock the specified mail file by setting the file mailfile.lock.
>  * We must, of course, be careful to unlink the lock file by a call
>  * to unlock before we stop.  The algorithm used here is to see if
>  * the lock exists, and if it does, to check its modify time.  If it
>  * is older than 300 seconds, we assume error and set our own file.
>  * Otherwise, we wait for 5 seconds and try again.
>  */
>
> char  *maillock       = ".lock";              /* Lock suffix for mailname */
> char  *lockname       = "/var/spool/mail/tmXXXXXX";
> char  locktmp[30];                            /* Usable lock temporary */
> char  curlock[50];                            /* Last used name of lock */
> int   locked;                                 /* To note that we locked it */
>
> lock(file)
> char *file;
> {
>       register time_t t;
>       struct stat sbuf;
>       int statfailed;
>
>       if (locked || flgf)
>               return(0);
>       strcpy(curlock, file);
>       strcat(curlock, maillock);
>       strcpy(locktmp, lockname);
>       mktemp(locktmp);
>       unlink(locktmp);
>       statfailed = 0;
>       for (;;) {
>               t = lock1(locktmp, curlock);
>               if (t == 0) {
>                       locked = 1;
>                       return(0);
>               }
>               if (stat(curlock, &sbuf) < 0) {
>                       if (statfailed++ > 5)
>                               return(-1);
>                       sleep(5);
>                       continue;
>               }
>               statfailed = 0;
>
>               /*
>                * Compare the time of the temp file with the time
>                * of the lock file, rather than with the current
>                * time of day, since the files may reside on
>                * another machine whose time of day differs from
>                * ours.  If the lock file is less than 5 minutes
>                * old, keep trying.
>                */
>               if (t < sbuf.st_ctime + 300) {
>                       sleep(5);
>                       continue;
>               }
>               unlink(curlock);
>       }
> }
>
> /*
>  * Remove the mail lock, and note that we no longer
>  * have it locked.
>  */
>
> unlock()
> {
>
>       unlink(curlock);
>       locked = 0;
> }
>
> /*
>  * Attempt to set the lock by creating the temporary file,
>  * then doing a link/unlink.  If it succeeds, return 0,
>  * else return a guess of the current time on the machine
>  * holding the file.
>  */
>
> lock1(tempfile, name)
>       char tempfile[], name[];
> {
>       register int fd;
>       struct stat sbuf;
>
>       fd = creat(tempfile, 0);
>       if (fd < 0)
>               return(time(0));
>       fstat(fd, &sbuf);
>       close(fd);
>       if (link(tempfile, name) < 0) {
>               unlink(tempfile);
>               return(sbuf.st_ctime);
>       }
>       unlink(tempfile);
>       return(0);
> }
>
> done()
> {
>       if(locked)
>               unlock();
>       unlink(lettmp);
>       unlink(locktmp);
>       exit(error);
> }
>
> cat(to, from1, from2)
>       char *to, *from1, *from2;
> {
>       register char *cp, *dp;
>
>       cp = to;
>       for (dp = from1; *cp = *dp++; cp++)
>               ;
>       for (dp = from2; *cp++ = *dp++; )
>               ;
> }
>
> /* copy p... into s, update p */
> char *
> getarg(s, p)
>       register char *s, *p;
> {
>       while (*p == ' ' || *p == '\t')
>               p++;
>       if (*p == '\n' || *p == '\0')
>               return(NULL);
>       while (*p != ' ' && *p != '\t' && *p != '\n' && *p != '\0')
>               *s++ = *p++;
>       *s = '\0';
>       return(p);
> }
>
> safefile(f)
>       char *f;
> {
>       struct stat statb;
>
>       if (lstat(f, &statb) < 0)
>               return (1);
>       if (statb.st_nlink != 1 || (statb.st_mode & S_IFMT) == S_IFLNK) {
>               fprintf(stderr,
>                   "mail: %s has more than one link or is a symbolic link\n",
>                   f);
>               return (0);
>       }
>       return (1);
> }
>
> panic(msg, a1, a2, a3)
>       char *msg;
> {
>
>       fprintf(stderr, "mail: ");
>       fprintf(stderr, msg, a1, a2, a3);
>       fprintf(stderr, "\n");
>       error = EX_OSERR;
>       done();
> }