[CRIU] [PATCH] restore: Compute auxv size taking into account kernel's mm::saved_auxv type

[Cyrill Gorcunov]

On Mon, Feb 10, 2014 at 03:22:16PM +0400, Pavel Emelyanov wrote:
> On 02/10/2014 03:15 PM, Cyrill Gorcunov wrote:
> > On 32-bit ARM machine we've got:
> > 
> >  | 10:45:28.595:  4927: new environ: GIT_URL=git://git.criu.org/crtools.git
> >  | 10:45:28.595:  4927: FAIL: cmdlinenv00.c:116: auxv corrupted on restore (errno = 11 (Resource temporarily unavailable))
> > 
> > that's because in commit 459828b6bec92d664bcce8419436e528be2094f2
> > we've changed reading procedure of auxv but forgot to update
> > restore procedure (which were thinking that size of vector
> > remains in number of "passes".
> 
> IOW, we broke backward compatibility, right?

Yes, sort of. When I've converted this read in 459828b6 I missed
the key point

-	for (i = 0; i < AT_VECTOR_SIZE; i++) {
-		ret = read(fd, &mm->mm_saved_auxv[i],
-			   sizeof(auxv_t));			<--
-		if (ret == 0)
-			break;
-		else if (ret != sizeof(auxv_t)) {
-			ret = -1;
-			pr_perror("Error reading %d's auxv[%d]",
-				  pid, i);
-			goto err;
-		}
-	}

sizeof(auxv_t) is different between 32bit and 64bit.