BSD 4_3 release

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

#ifndef lint
static char sccsid[] = "@(#)gename.c    5.6 (Berkeley) 10/9/85";
#endif

#include "uucp.h"

#define SEQLEN 4
#define SLOCKTIME 10L
#define SLOCKTRIES 5
/*
* the alphabet can be anything, but if it's not in ascii order,
* sequence ordering is not preserved
*/
static char alphabet[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

#ifdef BSD4_2
#include <sys/file.h>
#endif BSD4_2

/*LINTLIBRARY*/

/*
*      generate file name
*/
gename(pre, sys, grade, file)
char pre, *sys, grade, *file;
{
       register int i, fd;
       static char snum[5];
       static char *lastchar = NULL;

       if (lastchar == NULL || (snum[SEQLEN-1] = *(lastchar++)) == '\0') {
#ifndef BSD4_2
               for (i = 0; i < SLOCKTRIES; i++) {
                       if (!ulockf(SEQLOCK, SLOCKTIME))
                               break;
                       sleep(5);
               }

               if (i >= SLOCKTRIES) {
                       logent(SEQLOCK, "CAN NOT LOCK");
                       goto getrandseq;
               }
#endif !BSD4_2

               if ((fd = open(SEQFILE, 2)) >= 0) {
                       register char *p;
#ifdef BSD4_2
                       flock(fd, LOCK_EX);
#endif !BSD4_2
                       read(fd, snum, SEQLEN);
                       /* increment the penultimate character */
                       for (i = SEQLEN - 2; i >= 0; --i) {
                               if ((p = index(alphabet, snum[i])) == NULL)
                                       goto getrandseq;
                               if (++p < &alphabet[sizeof alphabet - 1]) {
                                       snum[i] = *p;
                                       break;
                               } else          /* carry */
                                       snum[i] = alphabet[0];  /* continue */
                       }
                       snum[SEQLEN-1] = alphabet[0];
               } else {
                       extern int errno;
                       fd = creat(SEQFILE, 0666);
getrandseq:             srand((int)time((time_t *)0));
                       assert(SEQFILE, "is missing or trashed\n", errno);
                       for (i = 0; i < SEQLEN; i++)
                               snum[i] = alphabet[rand() % (sizeof alphabet - 1)];
                       snum[SEQLEN-1] = alphabet[0];
               }

               if (fd >= 0) {
                       lseek(fd, 0L, 0);
                       write(fd, snum, SEQLEN);
                       close(fd);
               }
#ifndef BSD4_2
               rmlock(SEQLOCK);
#endif !BSD4_2
               lastchar = alphabet + 1;
       }
       sprintf(file,"%c.%.*s%c%.*s", pre, SYSNSIZE, sys, grade, SEQLEN, snum);
       DEBUG(4, "file - %s\n", file);
}