BSD 4 release

[unix-history] / usr / src / cmd / pwd.c

static char *sccsid = "@(#)pwd.c        4.1 (Berkeley) 10/1/80";
/*
* Print working (current) directory
*/
#include        <stdio.h>
#include        <sys/param.h>
#include        <sys/stat.h>
#include        <sys/dir.h>

char    dot[]   = ".";
char    dotdot[] = "..";
char    name[BUFSIZ];
int     file;
int     off     = -1;
struct  stat    d, dd;
struct  direct  dir;

main()
{
       int rdev, rino;

       stat("/", &d);
       rdev = d.st_dev;
       rino = d.st_ino;
       for (;;) {
               stat(dot, &d);
               if (d.st_ino==rino && d.st_dev==rdev)
                       prname();
               if ((file = open(dotdot,0)) < 0) {
                       fprintf(stderr,"pwd: cannot open ..\n");
                       exit(1);
               }
               fstat(file, &dd);
               chdir(dotdot);
               if(d.st_dev == dd.st_dev) {
                       if(d.st_ino == dd.st_ino)
                               prname();
                       do
                               if (read(file, (char *)&dir, sizeof(dir)) < sizeof(dir)) {
                                       fprintf(stderr,"read error in ..\n");
                                       exit(1);
                               }
                       while (dir.d_ino != d.st_ino);
               }
               else do {
                               if(read(file, (char *)&dir, sizeof(dir)) < sizeof(dir)) {
                                       fprintf(stderr,"read error in ..\n");
                                       exit(1);
                               }
                               stat(dir.d_name, &dd);
                       } while(dd.st_ino != d.st_ino || dd.st_dev != d.st_dev);
               close(file);
               cat();
       }
}

prname()
{
       write(1, "/", 1);
       if (off<0)
               off = 0;
       name[off] = '\n';
       write(1, name, off+1);
       exit(0);
}

cat()
{
       register i, j;

       i = -1;
       while (dir.d_name[++i] != 0);
       if ((off+i+2) > BUFSIZ-1)
               prname();
       for(j=off+1; j>=0; --j)
               name[j+i+1] = name[j];
       off=i+off+1;
       name[i] = '/';
       for(--i; i>=0; --i)
               name[i] = dir.d_name[i];
}