Patchwork [v3,BZ,21340] add support for POSIX_SPAWN_SETSID

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Submitter Adhemerval Zanella Netto
Date April 21, 2017, 3:35 p.m.
Message ID <e946d2f1-bc1c-29b3-a48d-08fe4d6e2412@linaro.org>
Download mbox | patch
Permalink /patch/20114/
State New
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Comments

Adhemerval Zanella Netto - April 21, 2017, 3:35 p.m.
On 21/04/2017 11:24, Florian Weimer wrote:
> On 04/21/2017 04:13 PM, Adhemerval Zanella wrote:
> 
>>     * conform/data/spawn.h-data: Add POSIX_SPAWN_SETSID flag.
> 
> I think this has to go away ...
> 
> 
>> diff --git a/posix/spawn.h b/posix/spawn.h
>> index 36e3867..8d2ace1 100644
>> --- a/posix/spawn.h
>> +++ b/posix/spawn.h
>> @@ -60,6 +60,7 @@ typedef struct
>>   #ifdef __USE_GNU
>>   # define POSIX_SPAWN_USEVFORK        0x40
>>   #endif
>> +#define POSIX_SPAWN_SETSID        0x80
> 
> 
> ... because this has to be governed by __GNU_SOURCE.
> 
>> +static int
>> +do_test (void)
>> +{
>> +  pid_t sid, child_sid;
>> +  int res;
>> +
>> +  /* Current session ID.  */
>> +  sid = getsid(0);
>> +  if (sid == (pid_t) -1)
>> +    FAIL_EXIT1 ("getsid (0): %m");
>> +
>> +  posix_spawnattr_t attrp;
>> +  posix_spawnattr_init (&attrp);
>> +  if (posix_spawnattr_setflags (&attrp, POSIX_SPAWN_SETSID))
>> +    FAIL_EXIT1 ("posix_spawnattr_setflags: %m");
> 
> Please run the test twice, once with setting POSIX_SPAWN_SETSID, and once without.
> 
> Thanks,
> Florian

I think this iteration should fix the issues you bring.

--

	Daurnimator  <quae@daurnimator.com>
        Adhemerval Zanella  <adhemerval.zanella@linaro.org>

        [BZ #21340]
        * posix/Makefile (tests): Add tst-posix_spawn-setsid to list of tests.
        * posix/spawn.h: define POSIX_SPAWN_SETSID flag.
        * posix/spawnattr_setflags.c (ALL_FLAGS): Add POSIX_SPAWN_SETSID to
        valid flags.
        * posix/tst-posix_spawn-setsid.c: Add test for POSIX_SPAWN_SETSID.
        * sysdeps/mach/hurd/spawni.c (__spawni): Implementation of
        POSIX_SPAWN_SETSID.
        * sysdeps/posix/spawni.c (__spawni): Likewise.
        * sysdeps/unix/sysv/linux/spawni.c (__spawni_child): Likewise.


---
Joseph Myers - April 21, 2017, 7:53 p.m.
On Fri, 21 Apr 2017, Adhemerval Zanella wrote:

> I think this iteration should fix the issues you bring.
> 
> --
> 
> 	Daurnimator  <quae@daurnimator.com>
>         Adhemerval Zanella  <adhemerval.zanella@linaro.org>
> 
>         [BZ #21340]
>         * posix/Makefile (tests): Add tst-posix_spawn-setsid to list of tests.
>         * posix/spawn.h: define POSIX_SPAWN_SETSID flag.
>         * posix/spawnattr_setflags.c (ALL_FLAGS): Add POSIX_SPAWN_SETSID to
>         valid flags.
>         * posix/tst-posix_spawn-setsid.c: Add test for POSIX_SPAWN_SETSID.
>         * sysdeps/mach/hurd/spawni.c (__spawni): Implementation of
>         POSIX_SPAWN_SETSID.
>         * sysdeps/posix/spawni.c (__spawni): Likewise.
>         * sysdeps/unix/sysv/linux/spawni.c (__spawni_child): Likewise.

I think you should also add a NEWS entry for the new feature.
Florian Weimer - April 21, 2017, 8:04 p.m.
* Adhemerval Zanella:

> +static int
> +do_test_setsid (bool test_setsid)

This should return void.

> +  if (test_setsid)
> +    {
> +      if (posix_spawnattr_setflags (&attrp, POSIX_SPAWN_SETSID))
> +	FAIL_EXIT1 ("posix_spawnattr_setflags: %m");
> +    }

You need to set errno before you can use %m.

> +  res = posix_spawnp (&child, "true", NULL, &attrp, args, environ);
> +  /* posix_spawnattr_destroy is noop.  */
> +  posix_spawnattr_destroy (&attrp);
> +
> +  if (res != 0)
> +    FAIL_EXIT1 ("posix_spawnp: %m");

Likewise.

> +static int
> +do_test (void)
> +{
> +  int ret = 0;
> +
> +  ret += do_test_setsid (false);
> +  ret += do_test_setsid (true);
> +
> +  return 0;
> +}

ret is effectively unused.

> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
> index d7f9e83..3cf77d5 100644
> --- a/sysdeps/unix/sysv/linux/spawni.c
> +++ b/sysdeps/unix/sysv/linux/spawni.c

> +  if ((attr->__flags & POSIX_SPAWN_SETSID) != 0
> +      && (ret = __setsid ()) < 0)
> +    goto fail;

I believe the assignment to ret is dead.

> +
>    /* Set the process group ID.  */
>    if ((attr->__flags & POSIX_SPAWN_SETPGROUP) != 0
>        && (ret = __setpgid (0, attr->__pgrp)) != 0)

Apparently, this is an existing problem with the code ...
Adhemerval Zanella Netto - April 21, 2017, 8:42 p.m.
On 21/04/2017 17:04, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> +static int
>> +do_test_setsid (bool test_setsid)
> 
> This should return void.

Ack.

> 
>> +  if (test_setsid)
>> +    {
>> +      if (posix_spawnattr_setflags (&attrp, POSIX_SPAWN_SETSID))
>> +	FAIL_EXIT1 ("posix_spawnattr_setflags: %m");
>> +    }
> 
> You need to set errno before you can use %m.

Ack.

> 
>> +  res = posix_spawnp (&child, "true", NULL, &attrp, args, environ);
>> +  /* posix_spawnattr_destroy is noop.  */
>> +  posix_spawnattr_destroy (&attrp);
>> +
>> +  if (res != 0)
>> +    FAIL_EXIT1 ("posix_spawnp: %m");
> 
> Likewise.

Ack.

> 
>> +static int
>> +do_test (void)
>> +{
>> +  int ret = 0;
>> +
>> +  ret += do_test_setsid (false);
>> +  ret += do_test_setsid (true);
>> +
>> +  return 0;
>> +}
> 
> ret is effectively unused.

Yeah, I though about doing that since we bail out with an exit for
failure. I will change it.

> 
>> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
>> index d7f9e83..3cf77d5 100644
>> --- a/sysdeps/unix/sysv/linux/spawni.c
>> +++ b/sysdeps/unix/sysv/linux/spawni.c
> 
>> +  if ((attr->__flags & POSIX_SPAWN_SETSID) != 0
>> +      && (ret = __setsid ()) < 0)
>> +    goto fail;
> 
> I believe the assignment to ret is dead.
> 
>> +
>>    /* Set the process group ID.  */
>>    if ((attr->__flags & POSIX_SPAWN_SETPGROUP) != 0
>>        && (ret = __setpgid (0, attr->__pgrp)) != 0)
> 
> Apparently, this is an existing problem with the code ...
> 

If I recall correctly, on initial iterations for posix_spawn rewrite I used the ret
return to signal the error, but it seems later I generalize to use errno instead.
I will fix this usage, but I think extra fixes should go to on a different patch.
Adhemerval Zanella Netto - April 21, 2017, 8:43 p.m.
On 21/04/2017 16:53, Joseph Myers wrote:
> On Fri, 21 Apr 2017, Adhemerval Zanella wrote:
> 
>> I think this iteration should fix the issues you bring.
>>
>> --
>>
>> 	Daurnimator  <quae@daurnimator.com>
>>         Adhemerval Zanella  <adhemerval.zanella@linaro.org>
>>
>>         [BZ #21340]
>>         * posix/Makefile (tests): Add tst-posix_spawn-setsid to list of tests.
>>         * posix/spawn.h: define POSIX_SPAWN_SETSID flag.
>>         * posix/spawnattr_setflags.c (ALL_FLAGS): Add POSIX_SPAWN_SETSID to
>>         valid flags.
>>         * posix/tst-posix_spawn-setsid.c: Add test for POSIX_SPAWN_SETSID.
>>         * sysdeps/mach/hurd/spawni.c (__spawni): Implementation of
>>         POSIX_SPAWN_SETSID.
>>         * sysdeps/posix/spawni.c (__spawni): Likewise.
>>         * sysdeps/unix/sysv/linux/spawni.c (__spawni_child): Likewise.
> 
> I think you should also add a NEWS entry for the new feature.
> 

I will add one.
Florian Weimer - April 21, 2017, 8:47 p.m.
* Adhemerval Zanella:

> I will fix this usage, but I think extra fixes should go to on a
> different patch.

Thanks, and agreed.

Patch

diff --git a/posix/Makefile b/posix/Makefile
index a6586ea..0fc509c 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -91,7 +91,7 @@  tests		:= test-errno tstgetopt testfnm runtests runptests \
 		   bug-getopt5 tst-getopt_long1 bug-regex34 bug-regex35 \
 		   tst-pathconf tst-getaddrinfo4 tst-rxspencer-no-utf8 \
 		   tst-fnmatch3 bug-regex36 tst-getaddrinfo5 \
-		   tst-posix_spawn-fd \
+		   tst-posix_spawn-fd tst-posix_spawn-setsid \
 		   tst-posix_fadvise tst-posix_fadvise64
 xtests		:= bug-ga2
 ifeq (yes,$(build-shared))
diff --git a/posix/spawn.h b/posix/spawn.h
index 36e3867..a1154a3 100644
--- a/posix/spawn.h
+++ b/posix/spawn.h
@@ -59,6 +59,7 @@  typedef struct
 #define POSIX_SPAWN_SETSCHEDULER	0x20
 #ifdef __USE_GNU
 # define POSIX_SPAWN_USEVFORK		0x40
+# define POSIX_SPAWN_SETSID		0x80
 #endif
 
 
diff --git a/posix/spawnattr_setflags.c b/posix/spawnattr_setflags.c
index 9b3d1e0..62d2f00 100644
--- a/posix/spawnattr_setflags.c
+++ b/posix/spawnattr_setflags.c
@@ -25,6 +25,7 @@ 
 		   | POSIX_SPAWN_SETSIGMASK				      \
 		   | POSIX_SPAWN_SETSCHEDPARAM				      \
 		   | POSIX_SPAWN_SETSCHEDULER				      \
+		   | POSIX_SPAWN_SETSID					      \
 		   | POSIX_SPAWN_USEVFORK)
 
 /* Store flags in the attribute structure.  */
diff --git a/posix/tst-posix_spawn-setsid.c b/posix/tst-posix_spawn-setsid.c
new file mode 100644
index 0000000..c2d9534
--- /dev/null
+++ b/posix/tst-posix_spawn-setsid.c
@@ -0,0 +1,92 @@ 
+/* Test posix_spawn setsid attribute.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#include <support/check.h>
+
+static int
+do_test_setsid (bool test_setsid)
+{
+  pid_t sid, child_sid;
+  int res;
+
+  /* Current session ID.  */
+  sid = getsid(0);
+  if (sid == (pid_t) -1)
+    FAIL_EXIT1 ("getsid (0): %m");
+
+  posix_spawnattr_t attrp;
+  /* posix_spawnattr_init should not fail (it basically memset the
+     attribute).  */
+  posix_spawnattr_init (&attrp);
+  if (test_setsid)
+    {
+      if (posix_spawnattr_setflags (&attrp, POSIX_SPAWN_SETSID))
+	FAIL_EXIT1 ("posix_spawnattr_setflags: %m");
+    }
+
+  /* Program to run.  */
+  char *args[2] = { (char *) "true", NULL };
+  pid_t child;
+
+  res = posix_spawnp (&child, "true", NULL, &attrp, args, environ);
+  /* posix_spawnattr_destroy is noop.  */
+  posix_spawnattr_destroy (&attrp);
+
+  if (res != 0)
+    FAIL_EXIT1 ("posix_spawnp: %m");
+
+  /* Child should have a different session ID than parent.  */
+  child_sid = getsid (child);
+
+  if (child_sid == (pid_t) -1)
+    FAIL_EXIT1 ("getsid (%i): %m", child);
+
+  if (test_setsid)
+    {
+      if (child_sid == sid)
+	FAIL_EXIT1 ("child session ID matched parent one");
+    }
+  else
+    {
+      if (child_sid != sid)
+	FAIL_EXIT1 ("child session ID did not match parent one");
+    }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  int ret = 0;
+
+  ret += do_test_setsid (false);
+  ret += do_test_setsid (true);
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/mach/hurd/spawni.c b/sysdeps/mach/hurd/spawni.c
index 284875a..7430383 100644
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -281,6 +281,9 @@  __spawni (pid_t *pid, const char *file,
     }
 #endif
 
+  if (!err && (flags & POSIX_SPAWN_SETSID) != 0)
+    err = __proc_setsid (proc);
+
   /* Set the process group ID.  */
   if (!err && (flags & POSIX_SPAWN_SETPGROUP) != 0)
     err = __proc_setpgrp (proc, new_pid, attrp->__pgrp);
diff --git a/sysdeps/posix/spawni.c b/sysdeps/posix/spawni.c
index 5cc2ad1..9cad25c 100644
--- a/sysdeps/posix/spawni.c
+++ b/sysdeps/posix/spawni.c
@@ -101,7 +101,8 @@  __spawni (pid_t *pid, const char *file,
 	 to POSIX.  */
       || ((flags & (POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF
 		    | POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER
-		    | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_RESETIDS)) == 0
+		    | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_RESETIDS
+		    | POSIX_SPAWN_SETSID)) == 0
 	  && file_actions == NULL))
     new_pid = __vfork ();
   else
@@ -159,6 +160,10 @@  __spawni (pid_t *pid, const char *file,
     }
 #endif
 
+  if ((flags & POSIX_SPAWN_SETSID) != 0
+      && __setsid () < 0)
+    _exit (SPAWN_ERROR);
+
   /* Set the process group ID.  */
   if ((flags & POSIX_SPAWN_SETPGROUP) != 0
       && __setpgid (0, attrp->__pgrp) != 0)
diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
index d7f9e83..3cf77d5 100644
--- a/sysdeps/unix/sysv/linux/spawni.c
+++ b/sysdeps/unix/sysv/linux/spawni.c
@@ -177,6 +177,10 @@  __spawni_child (void *arguments)
     }
 #endif
 
+  if ((attr->__flags & POSIX_SPAWN_SETSID) != 0
+      && (ret = __setsid ()) < 0)
+    goto fail;
+
   /* Set the process group ID.  */
   if ((attr->__flags & POSIX_SPAWN_SETPGROUP) != 0
       && (ret = __setpgid (0, attr->__pgrp)) != 0)