| Commit message (Expand) | Author | Age | Files | Lines |
|---|
| * | remove useless conditional before free from dynamic linker path code | Rich Felker | 2013-06-26 | 1 | -1/+1 |
| * | fix dynamic linker handling of empty path file or error reading path file•••previously, the path string was being used despite being invalid. with
this change, empty path file or error reading the path file is treated
as an empty path. this is preferable to falling back to a default
path, so that attacks to prevent reading of the path file could not
result in loading incorrect and possibly dangerous (outdated or
mismatching ABI) libraries from.
the code to strip the final newline has also been removed; now that
newline is accepted as a delimiter, it's harmless to leave it in
place.
| Rich Felker | 2013-06-26 | 1 | -4/+3 |
| * | make newline-delimited dynamic linker path file actually work•••apparently the original commit was never tested properly, since
getline was only ever reading one line. the intent was to read the
entire file, so use getdelim with the null byte as delimiter as a
cheap way to read a whole file into memory.
| Rich Felker | 2013-06-25 | 1 | -1/+1 |
| * | ensure that thread dtv pointer is never null to optimize __tls_get_addr | Rich Felker | 2013-06-03 | 1 | -4/+4 |
| * | make dynamic linker accept : or \n as path separator•••this allows /etc/ld-musl-$(ARCH).path to contain one path per line,
which is much more convenient for users than the :-delimited format,
which was a source of repeated and unnecessary confusion. for
simplicity, \n is also accepted in environment variables, though it
should probably not be used there.
at the same time, issues with overly long paths invoking UB or getting
truncated have been fixed. such issues should not have arisen with the
environment (which is size-limited) but could have been generated by a
path file larger than 2**31 bytes in length.
| Rich Felker | 2013-04-20 | 1 | -8/+8 |
| * | fix uninitialized map_len being used in munmap failure paths in load_library•••this bug seems to have been introduced when the map_library signatures
was changed to return the mapping in a temp dso structure instead of
into separate variables.
| Rich Felker | 2013-02-02 | 1 | -3/+2 |
| * | add support for RTLD_NOLOAD to dlopen•••based on patch by Pierre Carrier <pierre@gcarrier.fr> that just added
the flag constant, but with minimal additional code so that it
actually works as documented. this is a nonstandard option but some
major software (reportedly, Firefox) uses it and it was easy to add
anyway.
| Rich Felker | 2013-01-23 | 1 | -3/+7 |
| * | fix regression in dlsym: rejection of special RTLD_* handles as invalid | Rich Felker | 2013-01-23 | 1 | -1/+2 |
| * | fix warning building dynlink.c stub for static libc•••struct dso was not defined in this case, and it's not needed in the
code that was using it anyway; void pointers work just as well.
| Rich Felker | 2013-01-16 | 1 | -2/+2 |
| * | fix bug in dladdr that prevented resolving addresses in the PLT | Rich Felker | 2013-01-16 | 1 | -1/+1 |
| * | check for invalid handles in dlsym/dlclose•••this is wasteful and useless from a standpoint of sane programs, but
it is required by the standard, and the current requirements were
upheld with the closure of Austin Group issue #639:
http://austingroupbugs.net/view.php?id=639
| Rich Felker | 2013-01-10 | 1 | -1/+17 |
| * | fix breakage in ldd (failure to print library load address) | Rich Felker | 2012-12-15 | 1 | -2/+2 |
| * | fix ordering of shared library ctors with respect to libc init•••previously, shared library constructors were being called before
important internal things like the environment (extern char **environ)
and hwcap flags (needed for sjlj to work right with float on arm) were
initialized in __libc_start_main. rather than trying to have to
dynamic linker make sure this stuff all gets initialized right, I've
opted to just defer calling shared library constructors until after
the main program's entry point is reached. this also fixes the order
of ctors to be the exact reverse of dtors, which is a desirable
property and possibly even mandated by some languages.
the main practical effect of this change is that shared libraries
calling getenv from ctors will no longer fail.
| Rich Felker | 2012-11-30 | 1 | -3/+6 |
| * | eliminate gdb complaints about missing linux-gate.so.1•••actually, the hard-coded name should be eliminated too, and replaced
by a search for the soname in the headers, but that can be done
separately later.
| Rich Felker | 2012-11-25 | 1 | -1/+2 |
| * | fix typo in dynamic linker path file loading code•••fortunately the memory corruption could not hurt anything, but it
prevented clearing the final newline and thus prevented the last path
element from working.
| Rich Felker | 2012-11-17 | 1 | -1/+1 |
| * | arg-skipping code for powerpc dynamic linker•••this allows using the dynamic linker as a command to load programs.
| Rich Felker | 2012-11-17 | 1 | -0/+8 |
| * | dynamic linking support for powerpc•••incomplete but at least partly working. requires all files to be
compiled in the new "secure" plt model, not the old one that put plt
code in the data segment. TLS is untested but may work. invoking the
dynamic linker explicitly to load a program does not yet handle argv
correctly.
| Rich Felker | 2012-11-16 | 1 | -17/+16 |
| * | fix indention with spaces in powerpc asm | Rich Felker | 2012-11-14 | 2 | -27/+26 |
| * | Merge remote-tracking branch 'ppc-port/ppc-squashed' | Rich Felker | 2012-11-14 | 2 | -0/+31 |
| |\ |
|
| | * | PPC port cleaned up, static linking works well now. | rofl0r | 2012-11-13 | 3 | -24/+24 |
| | * | import preliminary ppc work by rdp. | Richard Pennington | 2012-11-13 | 2 | -0/+31 |
| * | | support ldso path files without final newline | Rich Felker | 2012-11-09 | 1 | -2/+5 |
| * | | change ldso path file logic to replace rather than add to search path•••this change was originally intended just to avoid repeated attempts to
open a nonexistant /etc/ls-musl-$(ARCH).path file, but I realized it
also prevents the default paths from being searched when such a path
file exists. despite the potential to break existing usage, I believe
the new behavior is the right behavior, and it's better to fix it
sooner rather than later. with the old behavior, it was impossible to
inhibit search of default paths which might contain musl-incompatible
libs (or even libs from a different cpu arch, on multi-arch machines).
| Rich Felker | 2012-11-08 | 1 | -2/+2 |
| |/ |
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| * | fix dlsym asm for mips•••saving the return address from the delay slot is not valid -- by the
time the instruction executes, the return address has already been
replaced.
| Rich Felker | 2012-11-08 | 1 | -1/+2 |
| * | remove one unnecessary static var from dynamic linker | Rich Felker | 2012-11-01 | 1 | -2/+2 |
| * | fix more unused variable warnings•••some of these were coming from stdio functions locking files without
unlocking them. I believe it's useful for this to throw a warning, so
I added a new macro that's self-documenting that the file will never
be unlocked to avoid the warning in the few places where it's wrong.
| Rich Felker | 2012-11-01 | 1 | -3/+2 |
| * | add dl_iterate_phdr interface•••patches by Alex Caudill (npx). the dynamic-linked version is almost
identical to the final submitted patch; I just added a couple missing
lines for saving the phdr address when the dynamic linker is invoked
directly to run a program, and removed a couple to avoid introducing
another unnecessary type. the static-linked version is based on npx's
draft. it could use some improvements which are contingent on the
startup code saving some additional information for later use.
| Rich Felker | 2012-10-31 | 2 | -7/+87 |
| * | support looking up thread-local objects with dlsym | Rich Felker | 2012-10-19 | 1 | -0/+6 |
| * | fix breakage in dlsym for looking up RTLD_DEFAULT, etc.•••this was broken during the early dynamic-linked TLS commits, which
rearranged some of the code for handling new relocation types.
| Rich Felker | 2012-10-19 | 1 | -2/+5 |
| * | fix microblaze asm relocations for shared libc•••only @PLT relocations are considered functions for purposes of
-Bsymbolic-functions, so always use @PLT. it should not hurt in the
static-linked case.
| Rich Felker | 2012-10-17 | 2 | -3/+3 |
| * | add support for TLS variant I, presently needed for arm and mips•••despite documentation that makes it sound a lot different, the only
ABI-constraint difference between TLS variants II and I seems to be
that variant II stores the initial TLS segment immediately below the
thread pointer (i.e. the thread pointer points to the end of it) and
variant I stores the initial TLS segment above the thread pointer,
requiring the thread descriptor to be stored below. the actual value
stored in the thread pointer register also tends to have per-arch
random offsets applied to it for silly micro-optimization purposes.
with these changes applied, TLS should be basically working on all
supported archs except microblaze. I'm still working on getting the
necessary information and a working toolchain that can build TLS
binaries for microblaze, but in theory, static-linked programs with
TLS and dynamic-linked programs where only the main executable uses
TLS should already work on microblaze.
alignment constraints have not yet been heavily tested, so it's
possible that this code does not always align TLS segments correctly
on archs that need TLS variant I.
| Rich Felker | 2012-10-15 | 1 | -3/+32 |
| * | fix main program TLS alignment for dynamic-linked programs•••this change brings the behavior in line with the static-linked code,
which seems to be correct.
| Rich Felker | 2012-10-14 | 1 | -6/+5 |
| * | fix namespace clash (libc) in dynlink.c•••this makes it so the #undef libc and __libc name are no longer needed,
which were problematic because the "accessor function" mode for
accessing the libc struct could not be used, breaking build on any
compiler without (working) visibility.
| Rich Felker | 2012-10-13 | 1 | -14/+13 |
| * | remove dead code from dynamic linker | Rich Felker | 2012-10-13 | 1 | -10/+0 |
| * | clean up and refactor program initialization•••the code in __libc_start_main is now responsible for parsing auxv,
rather than duplicating the parsing all over the place. this should
shave off a few cycles and some code size. __init_libc is left as an
external-linkage function despite the fact that it could be static, to
prevent it from being inlined and permanently wasting stack space when
main is called.
a few other minor changes are included, like eliminating per-thread
ssp canaries (they were likely broken when combined with certain
dlopen usages, and completely unnecessary) and some other unnecessary
checks. since this code gets linked into every program, it should be
as small and simple as possible.
| Rich Felker | 2012-10-07 | 1 | -2/+2 |
| * | fix breakage due to initializing thread pointer when loading libs•••at initial program load, all libraries must be loaded before the
thread pointer can be setup, since the TP-relative addresses of all
initial TLS objects must be constant.
| Rich Felker | 2012-10-07 | 1 | -1/+1 |
| * | make new TLS setup block even implementation-internals signals•••this is needed to ensure async-cancel-safety, i.e. to make it safe to
access TLS objects when async cancellation is enabled. otherwise, if
cancellation were acter upon after the atomic fetch/add but before the
thread saved the obtained memory, another access to the same TLS in
the cancellation handler could end up performing the atomic fetch/add
again, consuming more memory than is actually available and
overflowing into other objects on the heap.
| Rich Felker | 2012-10-06 | 1 | -2/+1 |
| * | don't crash if TLS library is loaded into process with no thread pointer | Rich Felker | 2012-10-06 | 1 | -0/+5 |
| * | fix symbol acceptance/rejection rules for TLS•••symbol value of 0 is not "undefined" for TLS; it's the address of the
first symbol in the TLS segment. however, non-definition TLS
references also have values of 0, so check the section.
hopefully the new logic is more clear, too.
| Rich Felker | 2012-10-06 | 1 | -8/+14 |
| * | TLS fixes, mainly alignment handling•••compute offsets from the thread pointer statically when loading the
library, rather than repeating the logic on each thread creation. not
only is the latter less efficient at runtime; it also fails to provide
solid guarantees that the offsets will remain the same when the
initial alignment of memory is different. the new alignment handling
is both more rigorous and simpler.
the old code was also clobbering TLS bss with random image data in
some cases due to using tls_size (size of TLS segment) instead of
tls_len (length of the TLS data image).
| Rich Felker | 2012-10-06 | 1 | -39/+48 |
| * | fix/improve shared library ctor/dtor handling, allow recursive dlopen•••some libraries call dlopen from their constructors, resulting in
recursive calls to dlopen. previously, this resulted in deadlock. I'm
now unlocking the dlopen lock before running constructors (this is
especially important since the lock also blocked pthread_create and
was being held while application code runs!) and using a separate
recursive mutex protecting the ctor/dtor state instead.
in order to prevent the same ctor from being called more than once, a
module is considered "constructed" just before the ctor runs.
also, switch from using atexit to register each dtor to using a single
atexit call to register the dynamic linker's dtor processing as just
one handler. this is necessary because atexit performs allocation and
may fail, but the library has already been loaded and cannot be
backed-out at the time dtor registration is performed. this change
also ensures that all dtors run after all atexit functions, rather
than in mixed order.
| Rich Felker | 2012-10-05 | 1 | -7/+29 |
| * | small dynamic linker module search fix•••libraries loaded more than once by pathname should not get shortnames
that would cause them to later be used to satisfy non-pathname load
requests.
| Rich Felker | 2012-10-05 | 1 | -1/+2 |
| * | support for TLS in dynamic-loaded (dlopen) modules•••unlike other implementations, this one reserves memory for new TLS in
all pre-existing threads at dlopen-time, and dlopen will fail with no
resources consumed and no new libraries loaded if memory is not
available. memory is not immediately distributed to running threads;
that would be too complex and too costly. instead, assurances are made
that threads needing the new TLS can obtain it in an async-signal-safe
way from a buffer belonging to the dynamic linker/new module (via
atomic fetch-and-add based allocator).
I've re-appropriated the lock that was previously used for __synccall
(synchronizing set*id() syscalls between threads) as a general
pthread_create lock. it's a "backwards" rwlock where the "read"
operation is safe atomic modification of the live thread count, which
multiple threads can perform at the same time, and the "write"
operation is making sure the count does not increase during an
operation that depends on it remaining bounded (__synccall or dlopen).
in static-linked programs that don't use __synccall, this lock is a
no-op and has no cost.
| Rich Felker | 2012-10-05 | 1 | -19/+81 |
| * | fix race condition in dlopen•••orig_tail was being saved before the lock was obtained, allowing
dlopen failure to roll-back other dlopens that had succeeded.
| Rich Felker | 2012-10-05 | 1 | -1/+3 |
| * | dynamic-linked TLS support for everything but dlopen'd libs•••currently, only i386 is tested. x86_64 and arm should probably work.
the necessary relocation types for mips and microblaze have not been
added because I don't understand how they're supposed to work, and I'm
not even sure if it's defined yet on microblaze. I may be able to
reverse engineer the requirements out of gcc/binutils output.
| Rich Felker | 2012-10-04 | 1 | -38/+58 |
| * | remove freeing of dynamic linker data when dlopen/dlsym are not used•••this was an optimization to save/recover a minimal amount of extra
memory for use by malloc, that's becoming increasingly costly to keep
around. freeing this data:
1. breaks debugging with gdb (it can't find library symbols)
2. breaks thread-local storage in shared libraries
it would be possible to disable freeing when TLS is used, but in
addition to the above breakages, tracking whether dlopen/dlsym is used
adds a cost to every symbol lookup, possibly making program startup
slower for large programs. combined with the complexity, it's not
worth it. we already save/recover plenty of memory in the dynamic
linker with reclaim_gaps.
| Rich Felker | 2012-10-04 | 1 | -11/+0 |
| * | beginnings of full TLS support in shared libraries•••this code will not work yet because the necessary relocations are not
supported, and cannot be supported without some internal changes to
how relocation processing works (coming soon).
| Rich Felker | 2012-10-04 | 1 | -0/+10 |
| * | partial TLS support for dynamic-linked programs•••only TLS in the main program is supported so far; TLS defined in
shared libraries will not work yet.
| Rich Felker | 2012-10-04 | 1 | -22/+72 |
| * | TLS (GNU/C11 thread-local storage) support for static-linked programs•••the design for TLS in dynamic-linked programs is mostly complete too,
but I have not yet implemented it. cost is nonzero but still low for
programs which do not use TLS and/or do not use threads (a few hundred
bytes of new code, plus dependency on memcpy). i believe it can be
made smaller at some point by merging __init_tls and __init_security
into __libc_start_main and avoiding duplicate auxv-parsing code.
at the same time, I've also slightly changed the logic pthread_create
uses to allocate guard pages to ensure that guard pages are not
counted towards commit charge.
| Rich Felker | 2012-10-04 | 1 | -0/+10 |
| * | more close-on-exec fixes, mostly using new "e" flag to fopen | Rich Felker | 2012-09-29 | 1 | -1/+1 |
