When a request needs to be resent (e.g. due to insufficient buffer
space), the references to subsequent tuples in the local variable are
stale and should not be used. This used to work by accident before, but
since 1d495912a it no longer does. Instead of trying to reset it, just
let gethostbyname4_r write into TUMPBUF6 for us, thus maintaining a
consistent state at all times. This is now consistent with what is done
in gaih_inet for getaddrinfo.
Resolves: BZ #29607
Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 6e33e5c4b7)
__nss_database_lookup2's extra arguments were left unused in the
nsswitch reloading patch set; this broke compat (default config
ignored) and shadow files (secondary name ignored) which relies on
these fallbacks.
This patch adds in the previous behavior by correcting the
initialization of the database list to reflect the fallbacks. This
means that the nss_database_lookup2 interface no longer needs to be
passed the fallback info, so API and callers were adjusted.
Since all callers needed to be edited anyway, the calls were changed
from __nss_database_lookup2 to the faster __nss_database_get. This
was an intended optimization which was deferred during the initial
lookup changes to avoid touching so many files.
The test case verifies that compat targets work (passwd) and that the
default configuration works (group). Tested on x86-64.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
The function uses the internal service_user type, so it is not
really usable from the outside of glibc. Rename the function
to __nss_database_lookup2 for internal use, and change
__nss_database_lookup to always indicate failure to the caller.
__nss_next already was a compatibility symbol. The new
implementation always fails and no longer calls __nss_next2.
unscd, the alternative nscd implementation, does not use
__nss_database_lookup, so it is not affected by this change.
This functionality was deprecated in glibc 2.25.
This commit only includes the core changes to remove the
functionality. It does not remove the RES_USE_INET6 handling in the
individual NSS service modules and the res_use_inet6 function.
These changes will happen in future commits.
The pre-allocation of the three scratch buffers increased the initial
stack size somewhat, but if retries are needed, the previous version
used more stack space if extend_alloca could not merge allocations.
Lack of alloca accounting also means could be problematic with
extremely large NSS responses, too.
[BZ #18023]
* nscd/aicache.c (addhstaiX): Use struct scratch_buffer instead
of extend_alloca.
As indicated by BZ#23178, concurrent access on some files read by nscd
may result non expected data send through service requisition. This is
due 'sendfile' Linux implementation where for sockets with zero-copy
support, callers must ensure the transferred portions of the the file
reffered by input file descriptor remain unmodified until the reader
on the other end of socket has consumed the transferred data.
I could not find any explicit documentation stating this behaviour on
Linux kernel documentation. However man-pages sendfile entry [1] states
in NOTES the aforementioned remark. It was initially pushed on man-pages
with an explicit testcase [2] that shows changing the file used in
'sendfile' call prior the socket input data consumption results in
previous data being lost.
From commit message it stated on tested Linux version (3.15) only TCP
socket showed this issues, however on recent kernels (4.4) I noticed the
same behaviour for local sockets as well.
Since sendfile on HURD is a read/write operation and the underlying
issue on Linux, the straightforward fix is just remove sendfile use
altogether. I am really skeptical it is hitting some hotstop (there
are indication over internet that sendfile is helpfull only for large
files, more than 10kb) here to justify that extra code complexity or
to pursuit other possible fix (through memory or file locks for
instance, which I am not sure it is doable).
Checked on x86_64-linux-gnu.
[BZ #23178]
* nscd/nscd-client.h (sendfileall): Remove prototype.
* nscd/connections.c [HAVE_SENDFILE] (sendfileall): Remove function.
(handle_request): Use writeall instead of sendfileall.
* nscd/aicache.c (addhstaiX): Likewise.
* nscd/grpcache.c (cache_addgr): Likewise.
* nscd/hstcache.c (cache_addhst): Likewise.
* nscd/initgrcache.c (addinitgroupsX): Likewise.
* nscd/netgroupcache.c (addgetnetgrentX, addinnetgrX): Likewise.
* nscd/pwdcache.c (cache_addpw): Likewise.
* nscd/servicescache.c (cache_addserv): Likewise.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == nscd]
(sysdep-CFLAGS): Remove -DHAVE_SENDFILE.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_SENDFILE):
Remove define.
[1] http://man7.org/linux/man-pages/man2/sendfile.2.html
[2] 7b6a329977 (diff-efd6af3a70f0f07c578e85b51e83b3c3)
struct resolv_context objects provide a temporary resolver context
which does not change during a name lookup operation. Only when the
outmost context is created, the stub resolver configuration is
verified to be current (at present, only against previous res_init
calls). Subsequent attempts to obtain the context will reuse the
result of the initial verification operation.
struct resolv_context can also be extended in the future to store
data which needs to be deallocated during thread cancellation.
Many callers of __res_maybe_init also call _res_hconf_init.
Additional calls to the latter do not hurt because the function
does its work only once. (/etc/hosts.conf is not reloaded or
even checked for changes.) This means that we can simplify the
code by calling _res_hconf_init directly from __res_vinit.
_res_hconf.initialized was not suitable for use in a multi-threaded
environment due to the lack of atomics and memory barriers. Use of it was
also unnecessary because _res_hconf_init did the right thing by using
__libc_once. This patch fixes the glibc-internal uses by just calling
_res_hconf_init unconditionally, and switches to a release MO atomic store
for _res_hconf.initialized to fix the glibc side of the synchronization
problem (which will maintain backward compatibility, but cannot fix the
lack of acquire MO on any glibc-external loads).
[BZ #20477]
* resolv/res_hconf.c (do_init): Use atomic access.
* resolv/res_hconf.h: Add comments.
* nscd/aicache.c (addhstaiX): Call _res_hconf_init unconditionally.
* nss/getXXbyYY_r.c (REENTRANT_NAME): Likewise.
* sysdeps/posix/getaddrinfo.c (gaih_inet): Likewise.
This patch consolidates the code to initialize the header of a dataset
into a single set of functions (one for positive and another for
negative datasets) primarily to reduce repetition of code. The
secondary reason is to simplify Patch 2/2 which fixes the problem of
an uninitialized byte in the header by initializing an unused field in
the structure and hence preventing a possible data leak into the cache
file.
The nscd/*cache.c files contain assert()s, writeall() and sendfileall() calls
that invalidly use together &dataset->resp and total where either dataset or
dataset->head.recsize should be used instead one of the components. In the
writeall() and sendfileall() cases, it is unlikely to matter in practice, but
the assertions can fail sometimes without a proper reason.
The commit 20e498bd removes the pthread_mutex_rdlock() calls, but not the
corresponding pthread_mutex_unlock() calls. Also, the database lock is never
unlocked in one branch of the mempool_alloc() if.
I think unreproducible random assert(dh->usable) crashes in prune_cache() were
caused by this. But an easy way to make nscd threads hang with the broken
locking was.
2009-02-13 Ulrich Drepper <drepper@redhat.com>
[BZ #5381]
* nscd/nscd.h: Remove definitions and declarations for mem_in_flight.
Change mempool_alloc prototype.
* nscd/mem.c (gc): Don't handle mem_in_flight.
(mempool_alloc): Third parameter now only indicates whether this is the
first call (to allocate data) or not. If it is, get db rdlock.
Release it on error. Don't handle mem_in_flight.
* nscd/aicache.c (addhstaiX): Mark he parameter as const.
Adjust third parameter of mempool_alloc calls.
Nothing to do here in case mempool_alloc fails.
Avoid local variable shadowing parameter. No need to get db rdlock
before calling cache_add.
* nscd/cache.c (cache_add): Adjust call to mempool_alloc. There is
no mem_in_flight array anymore.
* nscd/connections.c: Remove definition and handling of mem_in_flight.
* nscd/grpcache.c (cache_addgr): Adjust third parameter of
mempool_alloc calls. Mark he parameter as const. Nothing to do here
in case mempool_alloc fails. No need to get db rdlock before calling
cache_add.
* nscd/hstcache.c (cache_addhst): Likewise.
* nscd/initgrcache.c (addinitgroupsX): Likewise.
* nscd/servicescache.c (cache_addserv): Likewise.
* nscd/pwdcache.c (cache_addpw): Likewise. Remove some debugging code.
whether this is in response of a cache refill. Check alignment
of package data. Revamp waking of pruning thread.
(prune_cache): Small optimization.
* nscd/nscd.h: Adjust cache_add prototypes.
* nscd/aicache.c: Adjust cache_add calls.
* nscd/grpcache.c: Likewise.
* nscd/hstcache.c: Likewise.
* nscd/initgrcache.c: Likewise.
* nscd/pwdcache.c: Likewise.
* nscd/servicescache.c: Likewise.
* nscd/connections.c (restart): Really disable cache use before
exec attempt. If it fails, reenable cache.
(nscd_run_prune): Initialize wakeup_time. After wakeup, set wakeup
time to max to be able to notice concurrent cache additions. Unlock
prune_lock while performing gc. Afterwards compute wakeup time with
current wakeup_time value in mind.
is the first use of the record, mark it as unusable.
* nscd/aicache.c: Don't touch the dataset after cache_add returns
reporting a failure.
* nscd/grpcache.c: Likewise
* nscd/hstcache.c: Likewise.
* nscd/initgrcache.c: Likewise.
* nscd/pwdcache.c: Likewise.
* nscd/servicecache.c: Likewise.
prototypes.
* include/arpa/nameser_compat.h: Define T_UNSPEC.
* nis/Versions (libnss_nis): Export _nss_nis_gethostbyname4_r.
(libnss_nisplus): Export _nss_nisplus_gethostbyname4_r.
* nis/nss_nis/nis-hosts.c (LINE_PARSER): Change to also handle
af==AF_UNSPEC.
(_nss_nis_gethostbyname4_r): New function.
* nis/nss_nisplus/nisplus-hosts.c (_nss_nisplus_parse_hostent):
Change to also handle af==AF_UNSPEC.
(get_tablename): New function. Use it to avoid duplication.
(_nss_nisplus_gethostbyname4_r): New function.
* nscd/aicache.c (addhstaiX): Use gethostbyname4_r function is
available.
* nss/Versions (libnss_files): Export _nss_files_gethostbyname4_r.
* nss/nss.h: Define struct gaih_addrtuple.
* nss/nss_files/files-hosts.c (LINE_PARSER): Change to also handle
af==AF_UNSPEC.
(_nss_files_gethostbyname4_r): New function.
* resolv/Versions (libnss_dns): Export _nss_dns_gethostbyname4_r.
* resolv/gethnmaddr.c: Adjust __libc_res_nsearch and __libc_res_nquery
calls.
* resolv/res_query.c (__libc_res_nquery): Take two additional
parameters for second answer buffer. Handle type=T_UNSPEC to mean
look up IPv4 and IPv6.
Change all callers.
* resolv/res_send.c (__libc_res_nsend): Take five aditional parameters
for an additional query and answer buffer. Pass to send_vc and
send_dg.
(send_vc): Send possibly two requests and receive two answers.
(send_dg): Likewise.
* resolv/nss_dns/dns-host.c: Adjust calls to __libc_res_nsearch and
__libc_res_nquery.
(_nss_dns_gethostbyname4_r): New function.
(gaih_getanswer_slice): Likewise.
(gaih_getanswer): Likewise.
* resolv/nss_dns/dns-canon.c (_nss_dns_getcanonname_r): Adjust
__libc_res_nquery call.
* resolv/nss_dns/dns-network.c (_nss_dns_getnetbyaddr_r): Likewise.
(_nss_dns_getnetbyname_r): Adjust __libc_res_nsearch call.
* sysdeps/posix/getaddrinfo.c: Use gethostbyname4_r function is
available.
2008-04-15 Ulrich Drepper <drepper@redhat.com>
[BZ #5209]
* sysdeps/unix/sysv/linux/times.c: New file.
[BZ #5381]
* nscd/nscd.h: Define enum in_flight, mem_in_flight, and
mem_in_flight_list variables. Add new parameter to mempool_alloc
prototype.
* nscd/mem.c (mempool_alloc): Take additional parameter. Initialize
appropriate mem_in_flight element.
(gc): Take allocations which have not yet been committed to the
database into account.
* nscd/cache.c (cache_add): Add new parameter to mempool_alloc call.
Reset mem_in_flight before returning.
* nscd/connections.c (nscd_run_worker): Initialize mem_in_flight and
cue it up in mem_in_flight_list.
* nscd/aicache.c: Adjust mempool_alloc call.
* nscd/grpcache.c: Likewise.
* nscd/hstcache.c: Likewise.
* nscd/initgrcache.c: Likewise.
* nscd/pwdcache.c: Likewise.
* nscd/servicescache.c: Likewise.
* nscd/Makefile (nscd-flags): Until ld is fixed, use -fpic instead
of -fpie.
* nscd/connections.c (handle_request): Provide better error message
in case SELinux forbids the service.
* version.h (VERSION): Bump to 2.8.90.
* nscd/mem.c (MAX_STACK_USE): Remove definition here.
(gc): Initialize stack_used based on allocation in prune_cache.
* nscd/cache.c (prune_cache): Use heap for mark array if necessary.
Clear array bfore use.
* nscd/aicache.c (addhstaiX): Update statistics counter in case
memory allocate failed.
when the lookup call failed.
* nscd/nscd.h (struct database_dyn): Rename prunelock to prune_lock.
Add prune_cond and wakeup_time.
(CACHE_PRUNE_INTERNAL): Define.
Update declarations of prune_cache and setup_thread.
* nscd/connections.c (dbs): Update initializers.
(CACHE_PRUNE_INTERNAL): Moved to nscd.h.
(nscd_init): Default number of threads is now 4.
(invalidate_cache): Take lock before calling prune_cache.
(handle_request): If SELinux forbids the request, say so.
(readylist_cond): Use static initializer.
(nscd_run_prune): New function. Used only by pruning threads.
(nscd_run_worder): Renamed from nscd_run. Remove support for pruning
here.
(fd_ready): Update nscd_run reference.
(start_threads): No need to initialize readylist_cond.
Start pruning threads separately.
* nscd/nscd_setup_thread.c: Change return value type to int and always
return 0.
* sysdeps/unix/sysv/linux/nscd_setup_thread.c: Change return value type
to int and return nonzero value if we can use the TID address hack.
* nscd/cache.c (cache_add): If next wakeup time of cleanup thread for
the database is later than the new entry's timeout, update the
wakeup time and wake the cleanup thread.
(prune_cache): Return seconds the next entry in the database is still
valid. Remove locking for pruning here.
* nscd/nscd.conf: Document default number of threads.
gethstbynm3_r.
* nscd/gethstbynm2_r.c: Remove.
* nscd/gethstbynm3_r.c: New file.
* nscd/aicache.c (addhstaiX): Use __gethostbyaddr2_r instead of
__gethostbyaddr_r.
* nscd/gethstbyad_r.c: Generate __gethostbyaddr2_r function. Define
__gethostbyaddr_r compatibility wrapper.
* nscd/hstcache.c (cache_addhst): Add ttl parameter. Use it when
determining timeout of entry.
(lookup): Take new parameter and pass it to __gethostbyname3_r and
__gethostbyaddr2_r.
(addhstbyX): Pass reference to variable for TTL to lookup and
cache_addhst.
* nss/Versions [glibc] (GLIBC_PRIVATE): Export __nss_passwd_lookup2,
__nss_group_lookup2, __nss_hosts_lookup2, __nss_services_lookup2,
and __nss_next2. Remove __nss_services_lookup.
* nss/XXX-lookup.c: Name function now *_lookup2. Add new parameter.
Add compat wrapper.
* nss/getXXbyYY_r.c: Changes to call new *_lookup2 functions and
__nss_next2.
* nss/getXXent_r.c: Likewise.
* nss/getnssent_r.c: Likewise.
* nss/nsswitch.c (__nss_lookup): Add new parameter. If first function
does not exist in module, try the optional second name.
(__nss_next2): New function.
(__nss_next): Now wrapper around __nss_next2.
* nss/nsswitch.h: Adjust __nss_lookup prototype.
Declare __nss_next2.
Adjust definition of db_lookup_function type.
* nss/service-lookup.c: Define NO_COMPAT.
* include/netdb.h: Declare __gethostbyaddr2_r and __gethostbyname3_r.
* inet/ether_hton.c: Use __nss_next2 instead of __nss_next.
* inet/ether_ntoh.c: Likewise.
* sunrpc/netname.c: Likewise.
* sunrpc/publickey.c: Likewise.
* inet/getnetgrent.c: Likewise. Adjust calls to __nss_lookup.
* inet/gethstbyad_r.c (DB_LOOKUP_FCT): Change to __nss_hosts_lookup2.
* inet/gethstbynm2_r.c (DB_LOOKUP_FCT): Likewise.
* inet/gethstbynm_r.c (DB_LOOKUP_FCT): Likewise.
* inet/gethstent_r.c (DB_LOOKUP_FCT): Likewise.
* nscd/aicache.c (addhstaiX): Fix default TTL handling.
* inet/getnetgrent.c (setup): Encrypt static pointer.
