fix from rick adams

[unix-history] / usr / src / usr.bin / uucp / libuu / gename.c

#ifndef lint
static char sccsid[] = "@(#)gename.c    5.5 (Berkeley) %G%";
#endif

#include "uucp.h"

#define SEQLEN 4

/*LINTLIBRARY*/

/*
*      generate file name
*/
gename(pre, sys, grade, file)
char pre, *sys, grade, *file;
{
       static char sqnum[5];

       getseq(sqnum);
       sprintf(file,"%c.%.*s%c%.*s", pre, SYSNSIZE, sys, grade, SEQLEN, sqnum);
       DEBUG(4, "file - %s\n", file);
}

#define SLOCKTIME 10L
#define SLOCKTRIES 5

/*
*      get next sequence number
*/

static
getseq(snum)
register char *snum;
{
       /*
        * the alphabet can be anything, but if it's not in ascii order,
        * sequence ordering is not preserved
        */
       char    *alphabet =
           "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
       register int i, fd;
       static char *lastchar = NULL;

       if (lastchar == NULL || (snum[SEQLEN-1] = *(lastchar++)) == '\0') {
               for (i = 0; i < SLOCKTRIES; i++) {
                       if (!ulockf(SEQLOCK, SLOCKTIME))
                               break;
                       sleep(5);
               }

               if (i >= SLOCKTRIES) {
                       int alphalen;
                       logent(SEQLOCK, "CAN NOT LOCK");
                       alphalen = strlen(alphabet);
                       srand((int)time((time_t *)0));
                       for (i=1;i<SEQLEN;i++)
                               *snum++ = alphabet[rand() % alphalen];
                       lastchar = alphabet;
                       *snum = *lastchar++;
                       return;
               }

               if ((fd = open(SEQFILE, 2)) >= 0) {
                       int alphalen;
                       register char   *p;
                       char *index();

                       alphalen = strlen(alphabet);
                       read(fd, snum, SEQLEN);
                       /* initialize rand() for possible use */
                       srand((int)time((time_t *)0));
                       /* increment the penultimate character */
                       for (i = SEQLEN - 2; i >= 0; --i) {
                               if ((p = index(alphabet, snum[i])) == NULL) {
                                       p = &alphabet[rand() % alphalen];
                                       DEBUG(6, "bad seqf: %s\n", snum);
                               }
                               if (++p < &alphabet[alphalen]) {
                                       snum[i] = *p;
                                       break;
                               } else          /* carry */
                                       snum[i] = alphabet[0];  /* continue */
                       }
                       snum[SEQLEN-1] = alphabet[0];
               } else {
                       for (i = 0; i < SEQLEN; i++)
                               snum[i] = alphabet[0];
                       if ((fd = creat(SEQFILE, 0666)) < 0)
                               return;
               }

               lseek(fd, 0L, 0);
               write(fd, snum, SEQLEN);
               close(fd);
               rmlock(SEQLOCK);
               lastchar = alphabet + 1;
       }
       return;
}