Add sysentvec->sv_fixlimits() hook so that we can catch cases on 64 bit

systems where the data/stack/etc limits are too big for a 32 bit process.

Move the 5 or so identical instances of ELF_RTLD_ADDR() into imgact_elf.c.

Supply an ia32_fixlimits function.  Export the clip/default values to
sysctl under the compat.ia32 heirarchy.

Have mmap(0, ...) respect the current p->p_limits[RLIMIT_DATA].rlim_max
value rather than the sysctl tweakable variable.  This allows mmap to
place mappings at sensible locations when limits have been reduced.

Have the imgact_elf.c ld-elf.so.1 placement algorithm use the same
method as mmap(0, ...) now does.

Note that we cannot remove all references to the sysctl tweakable
maxdsiz etc variables because /etc/login.conf specifies a datasize
of 'unlimited'.  And that causes exec etc to fail since it can no
longer find space to mmap things.

1 files changed, 8 insertions, 1 deletions

diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 349078b..330437a 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -806,7 +806,14 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
 	vmspace->vm_dsize = data_size >> PAGE_SHIFT;
 	vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr;
 
-	addr = ELF_RTLD_ADDR(vmspace);
+	/*
+	 * We load the dynamic linker where a userland call
+	 * to mmap(0, ...) would put it.  The rationale behind this
+	 * calculation is that it leaves room for the heap to grow to
+	 * its maximum allowed size.
+	 */
+	addr = round_page((vm_offset_t)imgp->proc->p_vmspace->vm_daddr +
+	    imgp->proc->p_rlimit[RLIMIT_DATA].rlim_max);
 
 	imgp->entry_addr = entry;