Message-Id: <199902222318.XAA128862@out5.ibm.net>
From: "Mark E." <snowball3 AT usa DOT net>
To: djgpp-workers AT delorie DOT com
Date: Mon, 22 Feb 1999 18:18:35 -0500
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Subject: patches for chroot
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Reply-To: djgpp-workers AT delorie DOT com

Here's my first try at implementing chroot. I've modified putpath.c and 
unistd.h. New is chroot.c.

Without a reference I can check, I'm assuming in these patches that 
chroot is POSIX. Let me know if my assumption was wrong. With the 
patches.

These patches allow code like this to print "0" assuming you have gcc 
installed:

int status;

chroot ("c:/djgpp");
status = access ("bin/gcc.exe");

printf("status = %i\n", status);

I'll post my first cut at documenting 'chroot' tommorrow.

Mark

*** include/unistd.h.orig	Mon Jun 29 00:02:48 1998
--- include/unistd.h	Mon Feb 22 17:59:00 1999
***************
*** 76,81 ****
--- 76,82 ----
  unsigned int	alarm(unsigned int _seconds);
  int		chdir(const char *_path);
  int		chown(const char *_path, uid_t _owner, gid_t _group);
+ int		chroot(const char *_path);
  int		close(int _fildes);
  char *		ctermid(char *_s);
  int		dup(int _fildes);
*** src/libc/dos/io/putpath.c.orig	Thu Oct 29 10:24:44 1998
--- src/libc/dos/io/putpath.c	Mon Feb 22 18:02:02 1999
***************
*** 7,12 ****
--- 7,15 ----
  #include <stdlib.h>
  #include <string.h>
  #include <errno.h>
+ #include <unistd.h>
+ 
+ extern char _djgpp_root[];
  
  void
  _put_path(const char *path)
***************
*** 49,54 ****
--- 52,78 ----
      }
      else if (p[5])
        path = p + 5;
+   }
+ /* If the path is absolute and a root path is set,
+    then add the root path to the output. */
+   else if (path[0] == '/' && _djgpp_root[0] != '\0')
+   {
+     char *root = _djgpp_root;
+     char *abs_root = _djgpp_root;
+     if (abs_root[0] && abs_root[1] == ':')
+       abs_root += 2;
+     if (strncmp (abs_root, "/dev/", 5) == 0)
+     {
+       _farnspokeb (o++, abs_root[5]);
+       _farnspokeb (o++, ':');
+       space -= 2;
+       root = abs_root + 6;
+     }
+     for ( ; *root; root++)
+     {
+       _farnspokeb (o++, *root);
+       space -= 1;
+     }
    }
  
    /* collapse multiple slashes to a single slash */
*** chroot.c   Mon Feb 22 18:05:28 1999
--- src/libc/posix/unistd/chroot.c	Mon Feb 22 17:53:42 1999
***************
*** 0 ****
--- 1,22 ----
+ 
+ #include <unistd.h>
+ #include <fcntl.h>
+ #include <limits.h>
+ #include <sys/stat.h>
+ 
+ char _djgpp_root [PATH_MAX+1] = { '\0' };
+ 
+ int
+ chroot (const char *path)
+ {
+   if (path == NULL || *path == '\0')
+   {
+     _djgpp_root[0] = '\0';
+     return 0;
+   }
+ 
+   _fixpath (path, _djgpp_root);
+ 
+   return 0;
+ }
+ 

--- 
Mark Elbrecht
snowball3 AT usa DOT net http://members.xoom.com/snowball3/