Dima Dorfman <dima@bazooka> wrote:
> Chris Costello <[EMAIL PROTECTED]> wrote:
> >    I'd rewrite the above (`i = inet_aton' all the way down) as
> > 
> >      hp = gethostbyname(argv[3]);
> >      if (hp == NULL) {
> >              errx(1, "%s: %s", argv[3], hstrerror(h_errno));
> >      }
> >      in = *(struct in_addr *)hp->h_addr_list[0];
> > 
> >    This makes the call to inet_aton() unnecessary (and really
> > shortens the code!).
> 
> As discussed off-list, this is a good idea.  Attached is the final
> patch that I plan to commit unless I hear objections.  Please review.

Here's an updated patch which is a result of comments from a few
people.  The changes are: (a) deconfuse the usage message by not
naming two arguments as "hostname" (that was sloppiness on my part),
and (b) remove a redundant inet_aton call (gethostbyname(3) will DTRT
with an IP address) [1].

[1] It probably shouldn't, since as others have pointed out to me,
"1.1.1.1" is a valid DNS name.  The correct solution would be to have
a flag which makes it explicit whether the argument is an IP address
or DNS name, but few, if any, other programs in the system do this,
and I don't think this is a good place to start.

Index: jail.8
===================================================================
RCS file: /ref/cvsf/src/usr.sbin/jail/jail.8,v
retrieving revision 1.30
diff -u -r1.30 jail.8
--- jail.8      2001/09/03 15:42:10     1.30
+++ jail.8      2001/12/09 20:45:53
@@ -43,13 +43,16 @@
 .Nm
 .Ar path
 .Ar hostname
-.Ar ip-number
+.Ar address
 .Ar command
 .Ar ...
 .Sh DESCRIPTION
 The
 .Nm
 command imprisons a process and all future descendants.
+The supplied
+.Ar address
+may either be a hostname or IPv4 address.
 .Pp
 Please see the
 .Xr jail 2
Index: jail.c
===================================================================
RCS file: /ref/cvsf/src/usr.sbin/jail/jail.c,v
retrieving revision 1.7
diff -u -r1.7 jail.c
--- jail.c      2001/06/24 20:28:19     1.7
+++ jail.c      2001/12/09 20:50:20
@@ -14,23 +14,22 @@
 #include <sys/jail.h>
 
 #include <netinet/in.h>
-#include <arpa/inet.h>
 
 #include <err.h>
-#include <stdio.h>
+#include <netdb.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 int
 main(int argc, char **argv)
 {
+       struct hostent *hp;
        struct jail j;
        int i;
        struct in_addr in;
 
        if (argc < 5) 
-               errx(1, "Usage: %s path hostname ip-number command ...\n",
+               errx(1, "Usage: %s path hostname address command ...\n",
                    argv[0]);
        i = chdir(argv[1]);
        if (i)
@@ -39,9 +38,10 @@
        j.version = 0;
        j.path = argv[1];
        j.hostname = argv[2];
-       i = inet_aton(argv[3], &in);
-       if (!i)
-               errx(1, "Couldn't make sense of ip-number\n");
+       hp = gethostbyname(argv[3]);
+       if (hp == NULL)
+               errx(1, "gethostbyname(%s): %s", argv[3], hstrerror(h_errno));
+       in = *(struct in_addr *)hp->h_addr;
        j.ip_number = ntohl(in.s_addr);
        i = jail(&j);
        if (i)

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