Bell 32V development

[unix-history] / usr / src / libI77 / pwd.c

/*
* Print working (current) directory
*/
#include        <sys/types.h>
#include        <sys/stat.h>
#include        <sys/dir.h>

char    dot[]   ".";
char    dotdot[]        "..";
char    root[]  "/";
char    name[512];
int     file;
int     off     -1;
struct  stat    x;
struct  direct  y;

main()
{
       for (;;) {
               stat(dot, &x);
               if ((file = open(dotdot,0)) < 0) prname();
               do {
                       if (read(file, &y, sizeof(y)) < sizeof(y))
                               prname();
               } while (y.d_ino != x.st_ino);
               close(file);
               if (y.d_ino == 2)
                       ckroot();
               cat();
               chdir(dotdot);
       }
}

ckroot()
{
       register i;

       if (stat(y.d_name,&x)<0 || chdir(root)<0 || (file=open(root,0))<0)
               prname();
       i = x.st_dev;
       do {
               if (read(file,&y,sizeof(y)) < sizeof(y))
                       prname();
               if (y.d_ino == 0)
                       continue;
               if (stat(y.d_name,&x) < 0)
                       prname();
       } while (x.st_dev!=i || (x.st_mode&S_IFMT)!=S_IFDIR);
       if (strcmp(dot, y.d_name) || strcmp(dotdot, y.d_name))
               cat();
       write(1, root, 1);
       prname();
}

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

cat()
{
       register i, j;

       i = -1;
       while (y.d_name[++i] != 0);
       if ((off+i+2) > 511)
               prname();
       for(j=off+1; j>=0; --j)
               name[j+i+1] = name[j];
       off=i+off+1;
       name[i] = root[0];
       for(--i; i>=0; --i)
               name[i] = y.d_name[i];
}