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Annotation of researchv10dc/cmd/netnews/src/logdir.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  *     UNIX shell - logdir routine
                      3:  *
                      4:  *     Joe Steffen
                      5:  *     Bell Telephone Laboratories
                      6:  *
                      7:  *     This routine does not use the getpwent(3) library routine
                      8:  *     because the latter uses the stdio package.  The allocation of
                      9:  *     storage in this package destroys the integrity of the shell's
                     10:  *     storage allocation.
                     11:  *
                     12:  *     Modified 2/82 by DJ Molny
                     13:  *
                     14:  *     This routine now implements name cacheing, so multiple requests
                     15:  *     for the same logdir do not result in multiple open/reads of
                     16:  *     /etc/passwd.  If the previous request was successful and the name
                     17:  *     is the same as the last request, the same login directory is returned.
                     18:  */
                     19: 
                     20: #define        BUFSIZ  160
                     21: 
                     22: static char line[BUFSIZ+1];
                     23: 
                     24: char *
                     25: logdir(name)
                     26: char *name;
                     27: {
                     28:        int     pwf;
                     29:        static char lastname[BUFSIZ+1];
                     30:        static char lastdir[BUFSIZ+1];
                     31:        register char *p;
                     32:        register int i, j;
                     33:        char *field();
                     34:        
                     35:        if (*lastdir && !strcmp(lastname,name))         /* djm */
                     36:                return(lastdir);
                     37: 
                     38:        strcpy(lastname,name);                  /* djm */
                     39:        strcpy(lastdir,"");                     /* djm */
                     40: 
                     41:        /* attempt to open the password file */
                     42:        if ((pwf = open("/etc/passwd", 0)) == -1)
                     43:                return(0);
                     44:                
                     45:        /* find the matching password entry */
                     46:        do {
                     47:                /* get the next line in the password file */
                     48:                i = read(pwf, line, BUFSIZ);
                     49:                for (j = 0; j < i; j++)
                     50:                        if (line[j] == '\n')
                     51:                                break;
                     52:                /* return a null pointer if the whole file has been read */
                     53:                if (j >= i)
                     54:                        return(0);
                     55:                line[++j] = 0;                  /* terminate the line */
                     56:                lseek(pwf, (long) (j - i), 1);  /* point at the next line */
                     57:                p = field(line);                /* get the logname */
                     58:        } while (strcmp(name, line) != 0);
                     59:        close(pwf);
                     60:        
                     61:        /* skip the intervening fields */
                     62:        p = field(p);
                     63:        p = field(p);
                     64:        p = field(p);
                     65:        p = field(p);
                     66:        
                     67:        /* return the login directory */
                     68:        field(p);
                     69:        strcpy(lastdir,p);                      /* djm */
                     70:        return(p);
                     71: }
                     72: 
                     73: static char *
                     74: field(p)
                     75: register char *p;
                     76: {
                     77:        while (*p && *p != ':')
                     78:                ++p;
                     79:        if (*p) *p++ = 0;
                     80:        return(p);
                     81: }

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