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Annotation of 43BSDReno/bin/ps/devname.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1989 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that: (1) source distributions retain this entire copyright
                      7:  * notice and comment, and (2) distributions including binaries display
                      8:  * the following acknowledgement:  ``This product includes software
                      9:  * developed by the University of California, Berkeley and its contributors''
                     10:  * in the documentation or other materials provided with the distribution
                     11:  * and in all advertising materials mentioning features or use of this
                     12:  * software. Neither the name of the University nor the names of its
                     13:  * contributors may be used to endorse or promote products derived
                     14:  * from this software without specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  */
                     19: 
                     20: #if defined(LIBC_SCCS) && !defined(lint)
                     21: static char sccsid[] = "@(#)devname.c  5.5 (Berkeley) 5/31/90";
                     22: #endif /* LIBC_SCCS and not lint */
                     23: 
                     24: #include <sys/types.h>
                     25: #include <sys/stat.h>
                     26: #include <sys/file.h>
                     27: #include <dirent.h>
                     28: #include <paths.h>
                     29: 
                     30: static struct devs {
                     31:        struct  devs *next;
                     32:        dev_t   dev;
                     33:        char    name[MAXNAMLEN+1];
                     34:        mode_t  type;
                     35: };
                     36: 
                     37: #define        hash(x) ((x)&0xff)
                     38: static struct devs *devhash[0xff];
                     39: 
                     40: static int devinit;
                     41: 
                     42: char *
                     43: devname(dev, type)
                     44:        dev_t dev;
                     45:        mode_t type;
                     46: {
                     47:        struct devs *devp;
                     48: 
                     49:        if (devinit == 0) {
                     50:                register struct devs *devpp;
                     51:                register struct dirent *entry;
                     52:                struct stat sb;
                     53:                DIR *dp = opendir(_PATH_DEV);
                     54:                int savewd = open(".", O_RDONLY, 0);
                     55:                mode_t specialtype;
                     56: 
                     57:                if (savewd == -1 || dp == NULL || chdir(_PATH_DEV) == -1)
                     58:                        return (NULL);
                     59:                while ((entry = readdir(dp)) != NULL) {
                     60:                        if (stat(entry->d_name, &sb) == -1)
                     61:                                continue;
                     62:                        switch(sb.st_mode&S_IFMT) {
                     63:                        case S_IFCHR:
                     64:                                specialtype = S_IFCHR;
                     65:                                break;
                     66:                        case S_IFBLK:
                     67:                                specialtype = S_IFBLK;
                     68:                                break;
                     69:                        default:
                     70:                                continue;
                     71:                        }
                     72:                        devp = (struct devs *)malloc(sizeof (struct devs));
                     73:                        if (devp == NULL)
                     74:                                return (NULL);
                     75:                        devp->type = specialtype;
                     76:                        devp->dev = sb.st_rdev;
                     77:                        strcpy(devp->name, entry->d_name);
                     78:                        devp->next = NULL;
                     79:                        if ((devpp = devhash[hash(sb.st_rdev)]) == NULL)
                     80:                                devhash[hash(sb.st_rdev)] = devp;
                     81:                        else {
                     82:                                for (;devpp->next != NULL; devpp = devpp->next)
                     83:                                        ;
                     84:                                devpp->next = devp;
                     85:                        }
                     86:                }
                     87:                fchdir(savewd);
                     88:                close(savewd);
                     89:                closedir(dp);
                     90:                devinit = 1;
                     91:        }
                     92:        for (devp = devhash[hash(dev)]; devp != NULL; devp = devp->next)
                     93:                if (dev == devp->dev && type == devp->type)
                     94:                        return(devp->name);
                     95: 
                     96:        return (NULL);
                     97: }
                     98: 
                     99: #ifdef TEST
                    100: main() {
                    101:        printf(" %s \n", devname(0));
                    102: }
                    103: #endif

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