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From: Aurelien Jarno <aurelien@aurel32.net>
To: libc-stable@sourceware.org
Subject: [COMMITTED 2.33 4/7] support: Add xclone
Date: Mon, 24 Jan 2022 23:48:54 +0100	[thread overview]
Message-ID: <20220124224857.3799610-4-aurelien@aurel32.net> (raw)
In-Reply-To: <20220124224857.3799610-1-aurelien@aurel32.net>

From: Adhemerval Zanella <adhemerval.zanella@linaro.org>

It is a wrapper for Linux clone syscall, to simplify the call to the
use only the most common arguments and remove architecture specific
handling (such as ia64 different name and signature).

(cherry picked from commit de8995a2a04163617c1a233b4b81356ef9f9741f)
---
 support/Makefile |  1 +
 support/xclone.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 support/xsched.h | 34 ++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+)
 create mode 100644 support/xclone.c
 create mode 100644 support/xsched.h

diff --git a/support/Makefile b/support/Makefile
index 3c0eb200c2..f631846c07 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -92,6 +92,7 @@ libsupport-routines = \
   xchdir \
   xchroot \
   xclock_gettime \
+  xclone \
   xclose \
   xchmod \
   xconnect \
diff --git a/support/xclone.c b/support/xclone.c
new file mode 100644
index 0000000000..924d2b8754
--- /dev/null
+++ b/support/xclone.c
@@ -0,0 +1,50 @@
+/* Auxiliary functions to issue the clone syscall.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#ifdef __linux__
+# include <support/check.h>
+# include <stackinfo.h>  /* For _STACK_GROWS_{UP,DOWN}.  */
+# include <xsched.h>
+
+pid_t
+xclone (int (*fn) (void *arg), void *arg, void *stack, size_t stack_size,
+	int flags)
+{
+  pid_t r = -1;
+
+# ifdef __ia64__
+  extern int __clone2 (int (*fn) (void *arg), void *stack, size_t stack_size,
+		       int flags, void *arg, ...);
+  r = __clone2 (f, stack, stack_size, flags, arg, /* ptid */ NULL,
+		/* tls */ NULL, /* ctid  */ ctid);
+# else
+#  if _STACK_GROWS_DOWN
+  r = clone (fn, stack + stack_size, flags, arg, /* ptid */ NULL,
+	     /* tls */ NULL, /* ctid */  NULL);
+#  elif _STACK_GROWS_UP
+  r = clone (fn, stack, flags, arg, /* ptid */ NULL, /* tls */ NULL,
+	     &ctid);
+#  endif
+# endif
+
+  if (r < 0)
+    FAIL_EXIT1 ("clone: %m");
+
+  return r;
+}
+#endif
diff --git a/support/xsched.h b/support/xsched.h
new file mode 100644
index 0000000000..eefd731940
--- /dev/null
+++ b/support/xsched.h
@@ -0,0 +1,34 @@
+/* Wrapper for sched.h functions.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef SUPPORT_XSCHED_H
+#define SUPPORT_XSCHED_H
+
+__BEGIN_DECLS
+
+#include <sched.h>
+#include <sys/types.h>
+
+#ifdef __linux__
+pid_t xclone (int (*fn) (void *arg), void *arg, void *stack,
+	      size_t stack_size, int flags);
+#endif
+
+__END_DECLS
+
+#endif
-- 
2.34.1


  parent reply	other threads:[~2022-01-24 22:49 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-24 22:48 [COMMITTED 2.33 1/7] support: Add helpers to create paths longer than PATH_MAX Aurelien Jarno
2022-01-24 22:48 ` [COMMITTED 2.33 2/7] realpath: Set errno to ENAMETOOLONG for result larger than PATH_MAX [BZ #28770] Aurelien Jarno
2022-01-24 22:48 ` [COMMITTED 2.33 3/7] tst-realpath-toolong: Fix hurd build Aurelien Jarno
2022-01-24 22:48 ` Aurelien Jarno [this message]
2022-01-24 22:48 ` [COMMITTED 2.33 5/7] getcwd: Set errno to ERANGE for size == 1 (CVE-2021-3999) Aurelien Jarno
2022-01-24 22:48 ` [COMMITTED 2.33 6/7] realpath: Avoid overwriting preexisting error (CVE-2021-3998) Aurelien Jarno
2022-01-24 22:48 ` [COMMITTED 2.33 7/7] Linux: Detect user namespace support in io/tst-getcwd-smallbuff Aurelien Jarno

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