libc: add setns()

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

libc/sysdeps/linux/common/Makefile.in

@@ -45,6 +45,7 @@ CSRC-$(UCLIBC_LINUX_SPECIFIC) += \
 	sendfile.c \
 	setfsgid.c \
 	setfsuid.c \
+	setns.c \
 	setresgid.c \
 	setresuid.c \
 	signalfd.c \

libc/sysdeps/linux/common/bits/sched.h

@@ -1,7 +1,6 @@
 /* Definitions of constants and data structure for POSIX 1003.1b-1993
    scheduling interface.
-   Copyright (C) 1996-1999,2001-2003,2005,2006,2007,2008
-   Free Software Foundation, Inc.
+   Copyright (C) 1996-2015 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
@@ -26,14 +25,17 @@
 
 
 /* Scheduling algorithms.  */
-#define SCHED_OTHER	0
-#define SCHED_FIFO	1
-#define SCHED_RR	2
+#define SCHED_OTHER		0
+#define SCHED_FIFO		1
+#define SCHED_RR		2
 #ifdef __USE_GNU
-# define SCHED_BATCH	3
+# define SCHED_BATCH		3
+# define SCHED_IDLE		5
+
+# define SCHED_RESET_ON_FORK	0x40000000
 #endif
 
-#ifdef __USE_MISC
+#ifdef __USE_GNU
 /* Cloning flags.  */
 # define CSIGNAL       0x000000ff /* Signal mask to be sent at exit.  */
 # define CLONE_VM      0x00000100 /* Set if VM shared between processes.  */
@@ -58,7 +60,6 @@
 				      force CLONE_PTRACE on this clone.  */
 # define CLONE_CHILD_SETTID 0x01000000 /* Store TID in userlevel buffer in
 					  the child.  */
-# define CLONE_STOPPED 0x02000000 /* Start in stopped state.  */
 # define CLONE_NEWUTS	0x04000000	/* New utsname group.  */
 # define CLONE_NEWIPC	0x08000000	/* New ipcs.  */
 # define CLONE_NEWUSER	0x10000000	/* New user namespace.  */
@@ -75,7 +76,7 @@ struct sched_param
 
 __BEGIN_DECLS
 
-#ifdef __USE_MISC
+#ifdef __USE_GNU
 /* Clone current process.  */
 extern int clone (int (*__fn) (void *__arg), void *__child_stack,
 		  int __flags, void *__arg, ...) __THROW;
@@ -85,8 +86,12 @@ extern int unshare (int __flags) __THROW;
 
 /* Get index of currently used CPU.  */
 extern int sched_getcpu (void) __THROW;
+
+/* Switch process to namespace of type NSTYPE indicated by FD.  */
+extern int setns (int __fd, int __nstype) __THROW;
 #endif
 
+
 __END_DECLS
 
 #endif	/* need schedparam */
@@ -124,7 +129,11 @@ typedef struct
 } cpu_set_t;
 
 /* Access functions for CPU masks.  */
-# define __CPU_ZERO_S(setsize, cpusetp) \
+# if __GNUC_PREREQ (2, 91)
+#  define __CPU_ZERO_S(setsize, cpusetp) \
+  do __builtin_memset (cpusetp, '\0', setsize); while (0)
+# else
+#  define __CPU_ZERO_S(setsize, cpusetp) \
   do {									      \
     size_t __i;								      \
     size_t __imax = (setsize) / sizeof (__cpu_mask);			      \
@@ -132,47 +141,53 @@ typedef struct
     for (__i = 0; __i < __imax; ++__i)					      \
       __bits[__i] = 0;							      \
   } while (0)
+# endif
 # define __CPU_SET_S(cpu, setsize, cpusetp) \
   (__extension__							      \
    ({ size_t __cpu = (cpu);						      \
-      __cpu < 8 * (setsize)						      \
+      __cpu / 8 < (setsize)						      \
       ? (((__cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]		      \
 	 |= __CPUMASK (__cpu))						      \
       : 0; }))
 # define __CPU_CLR_S(cpu, setsize, cpusetp) \
   (__extension__							      \
    ({ size_t __cpu = (cpu);						      \
-      __cpu < 8 * (setsize)						      \
+      __cpu / 8 < (setsize)						      \
       ? (((__cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]		      \
 	 &= ~__CPUMASK (__cpu))						      \
       : 0; }))
 # define __CPU_ISSET_S(cpu, setsize, cpusetp) \
   (__extension__							      \
    ({ size_t __cpu = (cpu);						      \
-      __cpu < 8 * (setsize)						      \
-      ? ((((__cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]	      \
+      __cpu / 8 < (setsize)						      \
+      ? ((((const __cpu_mask *) ((cpusetp)->__bits))[__CPUELT (__cpu)]	      \
 	  & __CPUMASK (__cpu))) != 0					      \
       : 0; }))
 
 # define __CPU_COUNT_S(setsize, cpusetp) \
   __sched_cpucount (setsize, cpusetp)
 
-# define __CPU_EQUAL_S(setsize, cpusetp1, cpusetp2) \
+# if __GNUC_PREREQ (2, 91)
+#  define __CPU_EQUAL_S(setsize, cpusetp1, cpusetp2) \
+  (__builtin_memcmp (cpusetp1, cpusetp2, setsize) == 0)
+# else
+#  define __CPU_EQUAL_S(setsize, cpusetp1, cpusetp2) \
   (__extension__							      \
-   ({ __cpu_mask *__arr1 = (cpusetp1)->__bits;				      \
-      __cpu_mask *__arr2 = (cpusetp2)->__bits;				      \
+   ({ const __cpu_mask *__arr1 = (cpusetp1)->__bits;			      \
+      const __cpu_mask *__arr2 = (cpusetp2)->__bits;			      \
       size_t __imax = (setsize) / sizeof (__cpu_mask);			      \
       size_t __i;							      \
       for (__i = 0; __i < __imax; ++__i)				      \
 	if (__arr1[__i] != __arr2[__i])					      \
 	  break;							      \
       __i == __imax; }))
+# endif
 
 # define __CPU_OP_S(setsize, destset, srcset1, srcset2, op) \
   (__extension__							      \
    ({ cpu_set_t *__dest = (destset);					      \
-      __cpu_mask *__arr1 = (srcset1)->__bits;				      \
-      __cpu_mask *__arr2 = (srcset2)->__bits;				      \
+      const __cpu_mask *__arr1 = (srcset1)->__bits;			      \
+      const __cpu_mask *__arr2 = (srcset2)->__bits;			      \
       size_t __imax = (setsize) / sizeof (__cpu_mask);			      \
       size_t __i;							      \
       for (__i = 0; __i < __imax; ++__i)				      \

libc/sysdeps/linux/common/setns.c

@@ -0,0 +1,15 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * setns() for uClibc
+ *
+ * Copyright (C) 2015 Bernhard Reutner-Fischer <uclibc@uclibc.org>
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+#include <sys/syscall.h>
+#include <sched.h>
+
+#ifdef __NR_setns
+_syscall2(int, setns, int, fd, int, nstype)
+#endif

libc/sysdeps/linux/common/stubs.c

@@ -346,6 +346,10 @@ make_stub(setfsgid)
 make_stub(setfsuid)
 #endif
 
+#if !defined __NR_setns && defined __UCLIBC_LINUX_SPECIFIC__
+make_stub(setns)
+#endif
+
 #if !defined __NR_setresgid32 && !defined __NR_setresgid && defined __UCLIBC_LINUX_SPECIFIC__
 make_stub(setresgid)
 #endif