use flock for mailbox locking

[unix-history] / usr / src / libexec / mail.local / mail.local.c

#ifndef lint
static char sccsid[] = "@(#)mail.local.c        4.22 (Berkeley) %G%";
#endif

#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[] = "/usr/spool/mail/";
char    mailfile[] = "/usr/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();
int     delex();
char    *ctime();
int     flgf;
int     flgp;
int     delflg = 1;
int     hseqno;
jmp_buf sjbuf;
int     rmail;

main(argc, argv)
char **argv;
{
       register i;

       mktemp(lettmp);
       unlink(lettmp);
       my_name = getlogin();
       if (my_name == NULL || *my_name == '\0') {
               struct passwd *pwent;
               pwent = getpwuid(getuid());
               if (pwent==NULL)
                       my_name = "???";
               else
                       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], "rhd")))
               printmail(argc, argv);
       else
               bulkmail(argc, argv);
       done();
}

setsig(i, f)
int i;
int (*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);
#ifdef notdef
       if (stat(mailfile, &statb) >= 0
           && (statb.st_mode & S_IFMT) == S_IFDIR) {
               strcat(mailfile, "/");
               strcat(mailfile, my_name);
       }
#endif
       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 (argc >= 3) {
                               strcpy(mailfile, argv[2]);
                               argv++, argc--;
                       }
                       break;

               case 'b':
                       forward = 1;
                       break;

               default:
                       panic("unknown option %c", argv[1][1]);
                       /*NOTREACHED*/
               }
       }
       malf = fopen(mailfile, "r");
       if (malf == NULL) {
               printf("No mail.\n");
               return;
       }
       flock(fileno(malf), LOCK_SH);
       copymt(malf, tmpf);
       fclose(malf);                   /* implicit unlock */
       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);
               fputs("? ", stdout);
               fflush(stdout);
               if (fgets(resp, LSIZE, stdin) == NULL)
                       break;
               switch (resp[0]) {

               default:
                       printf("usage\n");
               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 (!sendrmt(j, lfil, "/bin/mail"))
                                       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 /usr/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
       fd = open(mailfile, O_RDWR | O_CREAT, MAILMODE);
       if (fd >= 0) {
               flock(fd, LOCK_EX);
               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);           /* implict unlock */
       if (new)
               printf("New mail has arrived.\n");
       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;

       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;
{
       char truename[100];
       int first;
       register char *cp;
       int gaver = 0;
       char *newargv[1000];
       register char **ap;
       register char **vp;
       int dflag;

       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--;
               switch (cp[1]) {
               case 'r':
                       if (argc <= 1)
                               usage();
                       if (strcmp(my_name, "root") == 0 ||
                           strcmp(my_name, "daemon") == 0 ||
                           strcmp(my_name, "network") == 0 ||
                           strcmp(my_name, "uucp")) {
                               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 'd':
                       break;
               
               default:
                       usage();
               }
       }
       if (argc <= 1)
               usage();
       if (gaver == 0)
               strcpy(truename, my_name);
       time(&iop);
       fprintf(tmpf, "%s%s %s", from, truename, ctime(&iop));
       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 && 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, rcmd)
char *name;
char *rcmd;
{
       FILE *rmf, *popen();
       register char *p;
       char rsys[64], cmd[64];
       register local, pid;
       int sts;

       local = 0;
       if (index(name, '^')) {
               while (p = index(name, '^'))
                       *p = '!';
               if (strncmp(name, "researc", 7)) {
                       strcpy(rsys, "research");
                       if (*name != '!')
                               --name;
                       goto skip;
               }
       }
       if (*name=='!')
               name++;
       for(p=rsys; *name!='!'; *p++ = *name++)
               if (*name=='\0') {
                       local++;
                       break;
               }
       *p = '\0';
       if ((!local && *name=='\0') || (local && *rsys=='\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 (local)
               sprintf(cmd, "%s %s", rcmd, rsys);
       else {
               if (index(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, local ? !strcmp(rcmd, "/bin/mail") ? FORWARD : ORDINARY : REMOTE);
       exit(pclose(rmf) != 0);
}

usage()
{

       fprintf(stderr, "Usage: mail [ -f ] people . . .\n");
       error = EX_USAGE;
       done();
}

#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

notifybiff(msg)
       char *msg;
{
       static struct sockaddr_in addr;
       static int f = -1;

       if (addr.sin_family == 0) {
               struct hostent *hp = gethostbyname("localhost");
               struct servent *sp = getservbyname("biff", "udp");

               if (hp && sp) {
                       addr.sin_family = hp->h_addrtype;
                       bcopy(hp->h_addr, &addr.sin_addr, hp->h_length);
                       addr.sin_port = sp->s_port;
               }
       }
       if (addr.sin_family) {
               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, *fromaddr;
{
       char file[256];
       int mask, fd;
       struct passwd *pw;
#ifdef notdef
       struct stat statb;
#endif
       char buf[128];

       if (any(name, "!^"))
               return (sendrmt(n, name, 0));
       if ((pw = getpwnam(name)) == NULL) {
               printf("mail: can't send to %s\n", name);
               return(0);
       }
       cat(file, maildir, name);
#ifdef notdef
       if (stat(file, &statb) >= 0 && (statb.st_mode & S_IFMT) == S_IFDIR) {
               strcat(file, "/");
               strcat(file, name);
       }
#endif
       if (!safefile(file))
               return(0);
       fd = open(file, O_WRONLY | O_CREAT, MAILMODE);
       if (fd >= 0) {
               flock(fd, LOCK_EX);
               malf = fdopen(fd, "a");
       }
       if (fd < 0 || malf == NULL) {
               close(fd);
               printf("mail: %s: cannot append\n", file);
               return(0);
       }
       fchown(fd, pw->pw_uid, pw->pw_gid);
       sprintf(buf, "%s@%d\n", name, ftell(malf)); 
       copylet(n, malf, ORDINARY);
       fclose(malf);
       notifybiff(buf);
       return(1);
}

delex(i)
{
       setsig(i, delex);
       putc('\n', stderr);
       if (delflg)
               longjmp(sjbuf, 1);
       done();
}

done()
{

       unlink(lettmp);
       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");
       done();
}