From: Ian Campbell <Ian.Campbell@citrix.com>
Under Xen the toolstack is responsible for managing the domains in
the system, e.g. creating, destroying, and otherwise manipulating
them.
To do this it uses a number of ioctls on the /proc/xen/privcmd
device. Most of these (the MMAPBATCH ones) simply set things up such
that a subsequenct mmap call will map the desired guest memory. Since
valgrind has no way of knowing what the memory contains we assume
that it is all initialised (to do otherwise would require valgrind to
be observing the complete state of the system and not just the given
process).
The most interesting ioctl is XEN_IOCTL_PRIVCMD_HYPERCALL which
allows the toolstack to make arbitrary hypercalls. Although the
mechanism here is specific to the OS of the guest running the
toolstack the hypercalls themselves are defined solely by the
hypervisor. Therefore I have split support for this ioctl into a part
in syswrap-linux.c which handles the ioctl itself and passes things
onto a new syswrap-xen.c which handles the specifics of the
hypercalls themselves. Porting this to another OS should just be a
matter of wiring up syswrap-$OS.c to decode the ioctl and call into
syswrap-xen.c. In the future we may want to split this into
syswrap-$ARCH-xen.c but for now this is x86 only.
The hypercall coverage here is pretty small but is enough to get
reasonable(-ish) results out of the xl toolstack when listing,
creating and destroying domains.
One issue is that the hypercalls which are exlusively used by the
toolstacks (as opposed to those used by guest operating systems) are
not considered a stable ABI, since the hypervisor and the lowlevel
tools are considered a matched pair. This covers the sysctl and
domctl hypercalls which are a fairly large chunk of the support
here. I'm not sure how to solve this without invoking a massive
amount of duplication. Right now this targets the Xen unstable
interface (which will shortly be released as Xen 4.2), perhaps I can
get away with deferring this problem until the first change .
On the plus side the vast majority of hypercalls are not of interest
to the toolstack (they are used by guests) so we can get away without
implementing them.
Note: a hypercall only reads as many words from the ioctl arg
struct as there are actual arguments to that hypercall and the
toolstack only initialises the arguments which are used. However
there is no space in the DEFN_PRE_TEMPLATE prototype to allow this to
be communicated from syswrap-xen.c back to syswrap-linux.c. Since a
hypercall can have at most 5 arguments I have hackily stolen ARG8 for
this purpose.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12963
This is a slightly modified version of a patch provided by Petar Jovanovic
<petar.jovanovic@rt-rk.com>.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12960
If a segment is mapped with permission rwx, then map->rx
and map->rw will be true.
But due to the if (map->rx) {
...
} else if (map->rw) {
...
the (map->rw) part will not be executed.
If this mapping is the one which "gives" the nonempty rw map,
then this mapping will not be seen, and the following
vg_assert(has_nonempty_rw);
will fail.
This assert can be reproduced by doing
setarch i686 -X
./vg-in-place --tool=none none/tests/map_unmap
Note: the setarch i686 -X above has as effect to make all read
mapping also executable. So, a rw mapping becomes rwx and then
triggers the above asserts.
The setarch i686 -X also introduces a discrepancy between
the kernel mappings (rwx) and the valgrind aspacemgr view
(which believes it is a rw mapping).
This discrepancy causes a crash if giving --sanity-level=3.
A possible fix is to have valgrind calling the personality system call
and detecting if the READ_IMPLIES_EXEC bit (the -X arg to setarch)
was set, and then modify aspacemgr so that all read mapped segments
are automatically mapped x also.
This commit is the minimal fix allowing to run executables
launched with this READ_IMPLIES_EXEC.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12810
--trace-redir=yes shows that there are duplicated redir entries e.g.
--32537-- TOPSPECS of soname NONE filename /home/philippe/valgrind/m_redir_trace/memcheck/vgpreload_memcheck-amd64-linux.so
--32537-- libc.so* strcasecmp_l R-> (2014.0) 0x04c28bf0
--32537-- libc.so* strcasecmp_l R-> (2014.0) 0x04c28bf0
--32537-- libc.so* __GI_strcasecmp_l R-> (2014.0) 0x04c28b70
--32537-- libc.so* __GI_strcasecmp_l R-> (2014.0) 0x04c28b70
These are caused by the merging of identical debug entries always
adding the two primary names, even if the entries are exactly the same.
This patch avoids duplicated names in debug info if the entry to merge
has only one name identical to the entry name to which we are merging.
This avoids the useless duplicated redir entries, and slightly decreases
the "dinfo" memory usage.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12554
di->soname was not freed, so was leaked when debug info is removed.
free(soname) added in free_Debuginfo, after having verified
and then ensured that all soname are allocated in dinfo.
regtested on deb6/amd64
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12442
(found by running regression tests with an outer memcheck).
(validated by running all regression tests "natively" on x86 and amd64,
and re-running regressions tests with outer memcheck).
==7500== 160 bytes in 2 blocks are definitely lost in loss record 75 of 246
==7500== at 0x2803CEF7: vgPlain_arena_malloc (m_mallocfree.c:1599)
==7500== by 0x280AAFA5: vgModuleLocal_dinfo_zalloc (misc.c:48)
==7500== by 0x2804E2A4: vgPlain_newXA (m_xarray.c:68)
==7500== by 0x280B3CD6: unitary_range_list (readdwarf3.c:703)
==7500== by 0x280B66CF: parse_var_DIE (readdwarf3.c:1631)
==7500== by 0x280BA0A6: read_DIE (readdwarf3.c:3248)
==7500== by 0x280BA170: read_DIE (readdwarf3.c:3269)
==7500== by 0x280BABC4: T.364 (readdwarf3.c:3611)
==7500== by 0x280BC634: vgModuleLocal_new_dwarf3_reader (readdwarf3.c:4035)
==7500== by 0x280609F4: vgModuleLocal_read_elf_debug_info (readelf.c:2529)
==7500== by 0x2805BD31: vgPlain_di_notify_mmap (debuginfo.c:610)
==7500== by 0x280362E3: valgrind_main (m_main.c:1944)
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12419
Previously it looked for the debuginfo object for "/system/X" in
"/sdcard/symbols/system/X". This commit removes the requirement for
"system" as the first path component, so the mapping is now "/X" (viz,
any absolute path) to "/sdcard/symbols/X".
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12406
functions that do FP arithmetic. This is due to the Dwarf3 CFI
mentioning Dwarf registers above N_CFI_REGS, in particular FP
registers, which have values of about 80. This fixes the problem by
increasing N_CFI_REGS to a level that covers all known registers.
(n-i-bz)
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12393
(Rusty Russell, rusty@rustcorp.com.au)
tdb uses fcntl locks and mmap, and some of the tests fail under valgrind.
strace showed valgrind opening the tdb file, reading 1024 bytes, then closing
it. This is not allowed: POSIX says if you open and close a file, all fcntl
locks on it are dropped (insane, yes).
Finally got around to hacking the source to track this down: di_notify_mmap is
doing the damage. The simplest fix was to hand in an optional fd for it to
use, then have it do pread.
I had to fix your pread; surely this should seek back even if the platform
doesn't have pread support?
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12224
and use read_Type routines instead as they work rather better on strict
aligned (or semi-strict a la ARM) machines. Fixes#282527.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12083
