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[unix-history] / sys / ken / nami.c

#include "/sys/nsys/param.h"
#include "/sys/nsys/inode.h"
#include "/sys/nsys/user.h"
#include "/sys/nsys/systm.h"
#include "/sys/nsys/buf.h"

namei(func, flag)
int (*func)();
int flag;

/*
* func = function called to get name
*      &uchar if name is in user space
*      &schar if name is in system space
* flag = 0 if name is saught
*      1 if name is to be created
*      2 if name is to be deleted
* return is incremented locked inode.
*      NULL if name not found
*/

{
       struct inode *dp;
       int *bp;
       int i, j, c, eo;

       /*
        * start from indicated
        * directory
        */

       if((c=(*func)()) == '/')
               dp = rootdir; else
               dp = u.u_cdir;
       iget(dp->i_dev, dp->i_number);
       while(c == '/')
               c = (*func)();

cloop:
       /*
        * here dp contains pointer
        * to last component matched.
        */

       if(u.u_error)
               goto out;
       if(c == '\0')
               return(dp);

       /*
        * if there is another component,
        * must be a directory and
        * must have x permission
        */

       if((dp->i_mode&IFMT) != IFDIR) {
               u.u_error = ENOTDIR;
               goto out;
       }

       if(access(dp, IEXEC))
               goto out;

       /*
        * gather up name into
        * users' dir buffer
        */

       for(i=0; c!='/' && c!='\0' && u.u_error==0; i++) {
               if(i < DIRSIZ)
                       u.u_dbuf[i] = c;
               c = (*func)();
       }
       while(i < DIRSIZ)
               u.u_dbuf[i++] = '\0';
       while(c == '/')
               c = (*func)();
       if(u.u_error)
               goto out;

       /*
        * search the directory
        */

       u.u_offset[1] = 0;
       u.u_offset[0] = 0;
       u.u_segflg = 1;
       eo = 0;
       u.u_count = ldiv(0, dp->i_size1, 16);
       u.u_offset[1] = 0;
       bp = NULL;

eloop:
       i = lrem(0, u.u_offset[1], 512);
       if(u.u_count == 0) {
               if(bp != NULL)
                       brelse(bp);
               if(flag==1 && c=='\0') {
                       if(access(dp, IWRITE))
                               goto out;
                       u.u_pdir = dp;
                       if(eo)
                               u.u_offset[1] = eo-DIRSIZ-2; else
                               dp->i_flag =| IUPD;
                       return(NULL);
               }
               u.u_error = ENOENT;
               goto out;
       }
       if(i == 0) {
               if(bp != NULL)
                       brelse(bp);
               bp = bread(dp->i_dev,
                       bmap(dp, ldiv(0, u.u_offset[1], 512)));
       }
       for(j = -2; j<DIRSIZ; j++)
               u.u_dent.u_name[j] =
                       bp->b_addr[i++];
       u.u_offset[1] =+ DIRSIZ+2;
       u.u_count--;
       if(u.u_dent.u_ino == 0) {
               if(eo == 0)
                       eo = u.u_offset[1];
               goto eloop;
       }
       for(i=0; i<DIRSIZ; i++)
               if(u.u_dbuf[i] != u.u_dent.u_name[i])
                       goto eloop;
       if(bp != NULL)
               brelse(bp);
       if(flag==2 && c=='\0') {
               if(access(dp, IWRITE))
                       goto out;
               return(dp);
       }
       i = dp->i_dev;
       iput(dp);
       dp = iget(i, u.u_dent.u_ino);
       if(dp == NULL)
               return(NULL);
       goto cloop;

out:
       iput(dp);
       return(NULL);
}

schar()
{

       return(*u.u_dirp++ & 0377);
}

uchar()
{
       int c;

       c = fubyte(u.u_dirp++);
       if(c == -1)
               u.u_error = EFAULT;
       return(c);
}