Messages in this thread | | | Date | Thu, 28 May 2009 02:25:47 +0400 | From | Alexey Dobriyan <> | Subject | Re: [PATCH 18/38] C/R: core stuff |
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On Wed, May 27, 2009 at 04:56:27PM -0400, Oren Laadan wrote: > > Now here goes second version, with prefixes fixed (kstate_") like Ingo > > suggested and so Linus could look at the code and with C/R code moved > > close to usual code and with more checks added (which you should have > > already!) to not restore null selector in %cs for example. > > It is far from perfect. In fact, it's even clearly commented as such, > and exactly there. It would have been helpful if you pointed that > out in a review, or even - god forbid - sent a patch to improve it.
This is ridiculous.
First, you declare that restart(2) should be allowed for anyone(!). and then send patchset for inclusion in -mm which doesn't even check if selectors are right!
> But it works, and it lets people play with a more-than-a-toy > implementation and provide us with important feedback. Oh, and by > the way, it doesn't require that people use containers to try it out.
Setting up container for playing is not hard:
CLONE_NEWUTS=y CLONE_NEWIPC=y CLONE_NEWPID=y CLONE_NEWUSER=y CLONE_NEWNET=y
#define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sched.h> #include <sys/mount.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/wait.h> #include <fcntl.h>
#define CLONE_NEWNS 0x00020000 #define CLONE_NEWUTS 0x04000000 #define CLONE_NEWIPC 0x08000000 #define CLONE_NEWUSER 0x10000000 #define CLONE_NEWPID 0x20000000 #define CLONE_NEWNET 0x40000000
static int fn(void *_argv) { char **argv = (char **)_argv;
setsid(); setpgid(getpid(), getpid());
execve(argv[0], argv, __environ); return 1; }
int main(int argc, char *argv[]) { unsigned long flags = 0; int status; pid_t pid; void *p;
flags |= CLONE_NEWNS; flags |= CLONE_NEWUTS; flags |= CLONE_NEWIPC; flags |= CLONE_NEWUSER; flags |= CLONE_NEWPID; flags |= CLONE_NEWNET;
p = malloc(4 * 4096); if (!p) return 1; argv++; pid = clone(fn, p + 4 * 4096, flags, (void *)argv); fprintf(stderr, "pid = %d\n", pid); if (pid == -1) return 1; waitpid(pid, &status, __WALL); return 0; }
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