bug fix: missing chdir("..") when a directory is not readable

[unix-history] / usr / src / usr.bin / du / du.c

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Newcomb.
*
* %sccs.include.redist.c%
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)du.c        5.7 (Berkeley) %G%";
#endif /* not lint */

#include <sys/param.h>
#include <sys/stat.h>
#include <dirent.h>
#include <string.h>
#include <stdio.h>

typedef struct _ID {
       dev_t   dev;
       ino_t   inode;
} ID;

ID *files;
dev_t device;
int crossmounts, kvalue, listdirs, listfiles, maxfiles, numfiles;
char path[MAXPATHLEN + 1];

main(argc, argv)
       int argc;
       char **argv;
{
       extern int optind, errno;
       int ch;
       char *malloc(), top[MAXPATHLEN + 1];

       listdirs = crossmounts = 1;
       while ((ch = getopt(argc, argv, "aksx")) != EOF)
               switch(ch) {
               case 'a':
                       listfiles = 1;
                       break;
               case 'k':
                       kvalue = 1;
                       break;
               case 's':
                       listfiles = listdirs = 0;
                       break;
               case 'x':
                       crossmounts = 0;
                       break;
               case '?':
               default:
                       (void)fprintf(stderr,
                           "usage: du [-aksx] [name ...]\n");
                       exit(1);
               }
       argv += optind;

       files = (ID *)malloc((u_int)(sizeof(ID) * (maxfiles = 128)));

       if (!*argv)
               du(".");
       else {
               if (argv[1])
                       (void)getwd(top);
               for (;;) {
                       du(*argv);
                       if (!*++argv)
                               break;
                       if (chdir(top)) {
                               (void)fprintf(stderr, "du: %s: %s\n",
                                   top, strerror(errno));
                               exit(1);
                       }
               }
       }
       exit(0);
}

struct stat info;

du(arg)
       register char *arg;
{
       extern int errno;
       u_long total, descend();

       if (lstat(arg, &info)) {
               (void)fprintf(stderr, "du: %s: %s\n", arg, strerror(errno));
               return;
       }
       if ((info.st_mode&S_IFMT) != S_IFDIR) {
               (void)printf("%ld\t%s\n", kvalue ?
                   howmany(info.st_blocks, 2) : info.st_blocks, arg);
               return;
       }
       device = info.st_dev;
       (void)strcpy(path, arg);
       total = descend(path);
       if (!listfiles && !listdirs)
               (void)printf("%lu\t%s\n",
                   kvalue ? howmany(total, 2) : total, path);
}

u_long
descend(endp)
       register char *endp;
{
       extern int errno;
       register DIR *dir;
       register ID *fp;
       register struct dirent *dp;
       u_long total;
       char *realloc();

       if (info.st_nlink > 1) {
               for (fp = files + numfiles - 1; fp >= files; --fp)
                       if (info.st_ino == fp->inode &&
                           info.st_dev == fp->dev)
                               return(0L);
               if (numfiles == maxfiles)
                       files = (ID *)realloc((char *)files,
                           (u_int)(sizeof(ID) * (maxfiles += 128)));
               files[numfiles].inode = info.st_ino;
               files[numfiles].dev = info.st_dev;
               ++numfiles;
       }
       total = info.st_blocks;
       if ((info.st_mode&S_IFMT) == S_IFDIR) {
               if (info.st_dev != device && !crossmounts)
                       return(0L);
               if (chdir(endp)) {
                       (void)fprintf(stderr, "du: %s: %s\n",
                           path, strerror(errno));
                       return(total);
               }
               if (!(dir = opendir("."))) {
                       (void)fprintf(stderr, "du: %s: %s\n",
                           path, strerror(errno));
                       if (chdir("..")) {
                               /* very unlikely */
                               (void)fprintf(stderr, "du: ..: %s\n",
                                   strerror(errno));
                               exit(1);
                       }
                       return(total);
               }
               for (; *endp; ++endp);
               if (endp[-1] != '/')
                       *endp++ = '/';
               while (dp = readdir(dir)) {
                       if (dp->d_name[0] == '.' && (!dp->d_name[1] ||
                           dp->d_name[1] == '.' && !dp->d_name[2]))
                               continue;
                       bcopy(dp->d_name, endp, dp->d_namlen + 1);
                       if (lstat(dp->d_name, &info)) {
                               (void)fprintf(stderr, "du: %s: %s\n", path,
                                   strerror(errno));
                               continue;
                       }
                       total += descend(endp);
               }
               closedir(dir);
               if (chdir("..")) {
                       (void)fprintf(stderr, "du: ..: %s\n", strerror(errno));
                       exit(1);
               }
               *--endp = '\0';
               if (listdirs)
                       (void)printf("%lu\t%s\n",
                           kvalue ? howmany(total, 2) : total, path);
       }
       else if (listfiles)
               (void)printf("%lu\t%s\n",
                   kvalue ? howmany(total, 2) : total, path);
       return(total);
}