screwed up last time

[unix-history] / usr / src / lib / libc / gen / getcwd.c

/*      @(#)getcwd.c    4.5     (Berkeley)      %G%     */

/*
* Getwd
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/dir.h>

#define dot     "."
#define dotdot  ".."

#define prexit(s)       { strcpy(np, s); return (NULL); }

static  char *name;

static  DIR *file;
static  int off;
static  struct stat d, dd;
static  struct direct *dir;

char *
getwd(np)
       char *np;
{
       dev_t rdev;
       ino_t rino;

       off = -1;
       *np++ = '/';
       name = np;
       stat("/", &d);
       rdev = d.st_dev;
       rino = d.st_ino;
       for (;;) {
               stat(dot, &d);
               if (d.st_ino==rino && d.st_dev==rdev)
                       goto done;
               if ((file = opendir(dotdot)) == NULL)
                       prexit("getwd: cannot open ..");
               fstat(file->dd_fd, &dd);
               if (chdir(dotdot) < 0)
                       prexit("getwd: cannot chdir to ..");
               if (d.st_dev == dd.st_dev) {
                       if(d.st_ino == dd.st_ino)
                               goto done;
                       do
                               if ((dir = readdir(file)) == NULL)
                                       prexit("getwd: read error in ..");
                       while (dir->d_ino != d.st_ino);
               } else
                       do {
                               if ((dir = readdir(file)) == NULL)
                                       prexit("getwd: read error in ..");
                               stat(dir->d_name, &dd);
                       } while(dd.st_ino != d.st_ino || dd.st_dev != d.st_dev);
               closedir(file);
               cat();
       }
done:
       name--;
       if (chdir(name) < 0)
               prexit("getwd: can't change back");
       return (name);
}

cat()
{
       register i, j;

       i = -1;
       while (dir->d_name[++i] != 0);
       if ((off+i+2) > 1024-1)
               return;
       for(j=off+1; j>=0; --j)
               name[j+i+1] = name[j];
       if (off >= 0)
               name[i] = '/';
       off=i+off+1;
       name[off] = 0;
       for(--i; i>=0; --i)
               name[i] = dir->d_name[i];
}