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Adhemerval Zanella 342cc934a3 posix: Add terminal control setting support for posix_spawn 
Currently there is no proper way to set the controlling terminal through
posix_spawn in race free manner [1].  This forces shell implementations
to keep using fork+exec when launching background process groups,
even when using posix_spawn yields better performance.

This patch adds a new GNU extension so the creating process can
configure the created process terminal group.  This is done with a new
flag, POSIX_SPAWN_TCSETPGROUP, along with two new attribute functions:
posix_spawnattr_tcsetpgrp_np, and posix_spawnattr_tcgetpgrp_np.
The function sets a new attribute, spawn-tcgroupfd, that references to
the controlling terminal.

The controlling terminal is set after the spawn-pgroup attribute, and
uses the spawn-tcgroupfd along with current creating process group
(so it is composable with POSIX_SPAWN_SETPGROUP).

To create a process and set the controlling terminal, one can use the
following sequence:

    posix_spawnattr_t attr;
    posix_spawnattr_init (&attr);
    posix_spawnattr_setflags (&attr, POSIX_SPAWN_TCSETPGROUP);
    posix_spawnattr_tcsetpgrp_np (&attr, tcfd);

If the idea is also to create a new process groups:

    posix_spawnattr_t attr;
    posix_spawnattr_init (&attr);
    posix_spawnattr_setflags (&attr, POSIX_SPAWN_TCSETPGROUP
				     | POSIX_SPAWN_SETPGROUP);
    posix_spawnattr_tcsetpgrp_np (&attr, tcfd);
    posix_spawnattr_setpgroup (&attr, 0);

The controlling terminal file descriptor is ignored if the new flag is
not set.

This interface is slight different than the one provided by QNX [2],
which only provides the POSIX_SPAWN_TCSETPGROUP flag.  The QNX
documentation does not specify how the controlling terminal is obtained
nor how it iteracts with POSIX_SPAWN_SETPGROUP.  Since a glibc
implementation is library based, it is more straightforward and avoid
requires additional file descriptor operations to request the caller
to setup the controlling terminal file descriptor (and it also allows
a bit less error handling by posix_spawn).

Checked on x86_64-linux-gnu and i686-linux-gnu.

[1] https://github.com/ksh93/ksh/issues/79
[2] https://www.qnx.com/developers/docs/7.0.0/index.html#com.qnx.doc.neutrino.lib_ref/topic/p/posix_spawn.html

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-01-25 14:07:53 -03:00
..
arpa resolv: Move ns_samename into its own file, and into libc 2021-07-19 07:56:21 +02:00
bits Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
gnu Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
net Fix resolver if_* namespace (bug 17717). 2014-12-16 18:18:49 +00:00
netinet nss_files: Consolidate line parse declarations in <nss_files.h> 2020-07-21 07:33:20 +02:00
programs Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
protocols
rpc Handle out-of-memory case in svc_tcp.c/svc_unix.c:rendezvous_request. 2020-12-10 11:11:20 +01:00
rpcsvc Remove --enable-obsolete-nsl configure flag 2020-07-08 17:25:57 +02:00
sys Linux: Add epoll_pwait2 (BZ #27359) 2022-01-17 14:34:54 -03:00
aio.h Linux: Move aio_suspend, aio_suspend64, __aio_suspend_time64 to libc 2021-06-25 11:55:27 +02:00
aliases.h Remove --enable-obsolete-nsl configure flag 2020-07-08 17:25:57 +02:00
alloc_buffer.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
alloca.h Remove macros extend_alloca, extend_alloca_account [BZ #18023] 2018-06-27 19:20:37 +02:00
allocate_once.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
ar.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
argp-fmtstream.h Mark internal argp functions with attribute_hidden [BZ #18822] 2017-10-01 15:10:27 -07:00
argp.h ldbl-opt: Add argp_error and argp_failure (bug 23983) 2019-03-01 15:21:32 -03:00
argz.h Use libc_hidden_* for argz_next, __argz_next (bug 15105). 2018-02-15 21:00:02 +00:00
array_length.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
assert.h Introduce NO_RTLD_HIDDEN, make hurd use it instead of NO_HIDDEN 2017-10-03 01:33:38 +02:00
atomic.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
atomic_wide_counter.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
byteswap.h
clone_internal.h Add an internal wrapper for clone, clone2 and clone3 2021-07-14 06:33:58 -07:00
complex.h float128: Add private _Float128 declarations for libm. 2017-05-15 10:23:28 -03:00
cpio.h Add more headers to include/ for conform tests. 2014-12-11 21:41:30 +00:00
crypt.h Add include/crypt.h. 2016-10-28 22:40:16 -04:00
ctype.h Use libc_hidden_* for tolower, toupper (bug 15105). 2018-02-23 13:54:53 +00:00
des.h
dirent.h Use 64 bit time_t stat internally 2021-06-22 12:09:52 -03:00
dlfcn.h elf: Add _dl_find_object function 2021-12-28 22:52:56 +01:00
dso_handle.h Mark __dso_handle as hidden [BZ #18822] 2017-09-26 16:53:44 -07:00
elf.h elf: Refuse to dlopen PIE objects [BZ #24323] 2019-06-18 16:42:10 +02:00
endian.h
envz.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
err.h ldbl-128ibm-compat: PLT redirects for using ldbl redirects internally 2020-03-25 14:34:23 -05:00
errno.h Remove tls.h inclusion from internal errno.h 2020-11-13 12:59:19 -03:00
error.h ldbl-opt: Add error and error_at_line (bug 23984) 2019-03-01 15:26:36 -03:00
execinfo.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
fcntl.h Fix Linux fcntl OFD locks for non-LFS architectures (BZ#20251) 2018-06-26 13:22:53 -03:00
features-time64.h y2038: Add support for 64-bit time on legacy ABIs 2021-06-15 10:42:11 -03:00
features.h Enable _FORTIFY_SOURCE=3 for gcc 12 and above 2022-01-12 18:46:28 +05:30
fenv.h Move fenv.h soft-float inlines from fenv_private.h to include/fenv.h. 2018-09-04 19:52:06 +00:00
file_change_detection.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
filename.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
float.h Make totalorder and totalordermag functions take pointer arguments. 2019-08-15 15:18:34 +00:00
fmtmsg.h Add more headers to include/ for conform tests. 2014-12-11 21:41:30 +00:00
fnmatch.h
fpu_control.h Hide internal __setfpucw function [BZ #18822] 2017-10-01 17:52:15 -07:00
fstab.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
fts.h io: Add fts64 with 64-bit time_t support 2021-06-15 10:42:11 -03:00
ftw.h io: Add ftw64 with 64-bit time_t support 2021-06-15 10:42:11 -03:00
gconv.h
getopt.h getopt: remove USE_NONOPTION_FLAGS 2017-04-07 07:45:53 -04:00
getopt_int.h
glob.h Fix extra PLT reference in libc.so due to __glob64_time64 if build with gcc 7.5 on 32bit. 2021-07-01 16:46:59 +02:00
gmp.h Mark internal gmp functions with attribute_hidden [BZ #18822] 2017-10-01 15:15:30 -07:00
gnu-versions.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
grp-merge.h NSS: Implement group merging support. 2016-04-29 22:18:21 -04:00
grp.h nss_files: Consolidate line parse declarations in <nss_files.h> 2020-07-21 07:33:20 +02:00
gshadow.h nss_files: Consolidate line parse declarations in <nss_files.h> 2020-07-21 07:33:20 +02:00
iconv.h
idx.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
ifaddrs.h hurd: Fix getifaddrs' and freeifaddrs' symbol exposition 2017-09-28 01:05:18 +02:00
ifreq.h Hide internal __ifreq function [BZ #18822] 2017-10-01 17:35:46 -07:00
ifunc-impl-list.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
inline-hashtab.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
intprops.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
inttypes.h Make strtoimax, strtoumax, wcstoimax, wcstoumax into aliases 2020-12-08 18:15:27 +00:00
langinfo.h
lastlog.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
libc-diag.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
libc-internal.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
libc-pointer-arith.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
libc-symbols.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
libgen.h
libintl.h Document the internal _ and N_ macros 2020-05-06 17:35:40 +02:00
limits.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
link.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
list.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
list_t.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
locale.h
loop_unroll.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
malloc.h Simplify __malloc_initialized 2021-07-22 18:38:04 +05:30
math-narrow-eval.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
math.h Redirect fma calls to __fma in libm 2021-09-15 22:57:35 +00:00
mcheck.h mcheck: Wean away from malloc hooks [BZ #23489] 2021-07-22 18:38:02 +05:30
memory.h
mntent.h Hide internal __hasmntopt function [BZ #18822] 2017-10-01 17:37:42 -07:00
monetary.h Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
mqueue.h Linux: Move mq_send, mq_timedsend, __mq_timedsend_time64 to libc 2021-06-25 12:21:12 +02:00
netdb.h nss_files: Move into libc 2021-07-07 18:33:52 +02:00
netgroup.h
nl_types.h
nss.h nss: Export nscd hash function as __nss_hash [BZ #22459] 2017-11-23 14:08:11 +01:00
nss_dns.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
nss_files.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
nsswitch.h
obstack.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
plural-exp.h Hide internal __gettextparse function [BZ #18822] 2017-10-01 17:31:05 -07:00
poll.h
printf.h Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
pthread.h Linux: Move mq_notify from librt to libc 2021-06-25 12:20:47 +02:00
pty.h login: Move libutil into libc 2021-06-30 08:43:37 +02:00
pwd.h nss_files: Consolidate line parse declarations in <nss_files.h> 2020-07-21 07:33:20 +02:00
random-bits.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
re_comp.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
regex.h regex: copy back from Gnulib 2021-09-21 08:00:44 -07:00
regexp.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
register-atfork.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
resolv.h resolv: Move res_queriesmatch to its own file and into libc 2021-07-19 07:56:21 +02:00
rounding-mode.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
rtld-malloc.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
sched.h Add hidden prototypes for __sched_getparam, __sched_getscheduler 2020-02-20 08:57:01 +01:00
scratch_buffer.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
search.h misc: Add twalk_r function 2019-05-02 11:42:51 +02:00
set-hooks.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
setjmp.h setjmp: Replace jmp_buf-macros.h with jmp_buf-macros.sym 2021-11-22 13:43:22 -03:00
sgtty.h
shadow.h nss_files: Consolidate line parse declarations in <nss_files.h> 2020-07-21 07:33:20 +02:00
shlib-compat.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
shm-directory.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
signal.h hurd: keep only required PLTs in ld.so 2020-11-11 02:36:22 +01:00
spawn.h posix: Use posix_spawn for wordexp 2019-10-09 17:48:41 -03:00
stab.h
stackinfo.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
stap-probe.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
stdc-predef.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
stdint.h Move inttypes.h and stdint.h to stdlib. 2019-03-13 09:42:09 -04:00
stdio.h libio: Replace internal _IO_getdelim symbol with __getdelim 2021-07-07 18:33:52 +02:00
stdio_ext.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
stdlib.h Remove __morecore and __default_morecore 2021-07-22 18:37:57 +05:30
string.h String: Add hidden defs for __memcmpeq() to enable internal usage 2021-10-26 16:51:29 -05:00
strings.h
struct___timeb64.h time: Add 64-bit time_t support for ftime 2020-10-27 09:54:50 -03:00
struct___timespec64.h y2038: include: Move struct __timespec64 definition to a separate file 2020-04-06 23:05:11 +02:00
struct___timeval64.h y2038: include: Move struct __timeval64 definition to a separate file 2020-05-05 19:36:25 +02:00
stubs-prologue.h
syscall.h
sysexits.h
syslog.h
tar.h
termios.h Hide internal __tcgetattr function [BZ #18822] 2017-10-01 17:48:24 -07:00
tgmath.h
time.h time: Fix overflow itimer tests on 32-bit systems 2021-08-15 07:09:58 +09:00
ttyent.h Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
uchar.h
ucontext.h
ulimit.h
unistd.h posix: Add terminal control setting support for posix_spawn 2022-01-25 14:07:53 -03:00
utime.h
utmp.h login: Move libutil into libc 2021-06-30 08:43:37 +02:00
values.h Update copyright dates with scripts/update-copyrights 2022-01-01 11:40:24 -08:00
verify.h posix: Sync regex with gnulib 2019-11-06 09:20:52 -03:00
wait.h Add missing header wrappers under include/ 2019-02-16 08:25:16 +01:00
wchar.h Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
wctype.h Remove __need macros from stdio.h and wchar.h. 2017-06-08 13:58:17 -04:00
wordexp.h