Linux-Clone/Clone.xs

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include <sys/errno.h>
#include <sys/mman.h>

#undef _GNU_SOURCE
#define _GNU_SOURCE
#include <sched.h>
#include <unistd.h>
#include <sys/syscall.h>

#include <sched.h>

#include <sys/ioctl.h>
#include <net/if.h>

#include <linux/nsfs.h>

#ifdef __has_include
  #if !__has_include("linux/kcmp.h") // use "" as GCC wrongly expands macros
    #undef SYS_kcmp
  #endif
#endif

#ifdef SYS_kcmp
  #include "linux/kcmp.h"
  #define kcmp(pid1,pid2,type,idx1,idx2) \
    syscall (SYS_kcmp, (pid_t)pid1, (pid_t)pid2, \
             (int)type, (unsigned long)idx1, (unsigned long)idx2)
#else
  #define kcmp(pid1,pid2,type,idx1,idx2) \
    (errno = ENOSYS, -1)
#endif

/* from schmorp.h */
static int
s_fileno (SV *fh, int wr)
{
  dTHX;
  SvGETMAGIC (fh);

  if (SvROK (fh))
    {
      fh = SvRV (fh);
      SvGETMAGIC (fh);
    }

  if (SvTYPE (fh) == SVt_PVGV)
    return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));

  if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
    return SvIV (fh);

  return -1;
}

static int
clone_cb (void *arg)
{
  dSP;

  PUSHMARK (SP);

  PUTBACK;
  int count = call_sv (sv_2mortal ((SV *)arg), G_SCALAR);
  SPAGAIN;
  int retval = count ? SvIV (POPs) : 0;
  PUTBACK;

  return retval;
}

MODULE = Linux::Clone           PACKAGE = Linux::Clone

PROTOTYPES: ENABLE

BOOT:
  HV *stash = gv_stashpv ("Linux::Clone", 1);

  static const struct {
    const char *name;
    IV iv;
  } *civ, const_iv[] = {
#   define const_iv(name)       { # name, (IV)name },
#   define const_iv_clone(name) { # name, (IV) CLONE_ ## name },
#   ifdef CSIGNAL
      const_iv (CSIGNAL)
#   endif
#   ifdef CLONE_FILES
      const_iv_clone (FILES)
#   endif
#   ifdef CLONE_FS
      const_iv_clone (FS)
#   endif
#   ifdef CLONE_NEWNS
      const_iv_clone (NEWNS)
#   endif
#   ifdef CLONE_VM
      const_iv_clone (VM)
#   endif
#   ifdef CLONE_THREAD
      const_iv_clone (THREAD)
#   endif
#   ifdef CLONE_SIGHAND
      const_iv_clone (SIGHAND)
#   endif
#   ifdef CLONE_SYSVSEM
      const_iv_clone (SYSVSEM)
#   endif
#   ifdef CLONE_NEWUTS
      const_iv_clone (NEWUTS)
#   endif
#   ifdef CLONE_NEWIPC
      const_iv_clone (NEWIPC)
#   endif
#   ifdef CLONE_NEWNET
      const_iv_clone (NEWNET)
#   endif
#   ifdef CLONE_PTRACE
      const_iv_clone (PTRACE)
#   endif
#   ifdef CLONE_VFORK
      const_iv_clone (VFORK)
#   endif
#   ifdef CLONE_SETTLS
      const_iv_clone (SETTLS)
#   endif
#   ifdef CLONE_PARENT_SETTID
      const_iv_clone (PARENT_SETTID)
#   endif
#   ifdef CLONE_CHILD_CLEARTID
      const_iv_clone (CHILD_CLEARTID)
#   endif
#   ifdef CLONE_DETACHED
      const_iv_clone (DETACHED)
#   endif
#   ifdef CLONE_UNTRACED
      const_iv_clone (UNTRACED)
#   endif
#   ifdef CLONE_CHILD_SETTID
      const_iv_clone (CHILD_SETTID)
#   endif
#   ifdef CLONE_NEWUSER
      const_iv_clone (NEWUSER)
#   endif
#   ifdef CLONE_NEWPID
      const_iv_clone (NEWPID)
#   endif
#   ifdef CLONE_IO
      const_iv_clone (IO)
#   endif
#   ifdef CLONE_NEWCGROUP
      const_iv_clone (NEWCGROUP)
#   endif
#   ifdef CLONE_PIDFD
      const_iv_clone (PIDFD)
#   endif
#   ifdef SYS_kcmp
      const_iv (KCMP_FILE)
      const_iv (KCMP_VM)
      const_iv (KCMP_FILES)
      const_iv (KCMP_FS)
      const_iv (KCMP_SIGHAND)
      const_iv (KCMP_IO)
      const_iv (KCMP_SYSVSEM)
      const_iv (KCMP_FILE)
#   endif
#   ifdef NS_GET_USERNS
      const_iv (NS_GET_USERNS)
#   endif
#   ifdef NS_GET_PARENT
      const_iv (NS_GET_PARENT)
#   endif
#   ifdef NS_GET_NSTYPE
      const_iv (NS_GET_NSTYPE)
#   endif
#   ifdef NS_OWNER_UID
      const_iv (NS_OWNER_UID
#   endif
  };

  for (civ = const_iv + sizeof (const_iv) / sizeof (const_iv [0]); civ > const_iv; civ--)
    newCONSTSUB (stash, (char *)civ[-1].name, newSViv (civ[-1].iv));

int
clone (SV *sub, IV stacksize, int flags, SV *ptid = 0, SV *tls = &PL_sv_undef)
        CODE:
{
        if (!stacksize)
          stacksize = 4 << 20;

        pid_t ptid_;
        char *stack_ptr = mmap (0, stacksize, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_GROWSDOWN | MAP_STACK, -1, 0);

        #ifndef __hppa
          stack_ptr += stacksize - 16; /* be safe and put the sp at 16 bytes below the end */
        #endif

        RETVAL = -1;
        if (stack_ptr != (void *)-1)
          {
            SV *my_sub = newSVsv (sub);
            
            RETVAL = clone (clone_cb, (void *)stack_ptr, flags, (void *)my_sub, &ptid, SvOK (tls) ? SvPV_nolen (tls) : 0, 0);

            if (ptid) sv_setiv (ptid, (IV)ptid_);

            if ((flags & (CLONE_VM | CLONE_VFORK)) != CLONE_VM)
              {
                int old_errno = errno;
                munmap (stack_ptr, stacksize);
                errno = old_errno;
              }
          }
}
        OUTPUT: RETVAL

int
unshare (int flags)

int
setns (SV *fh_or_fd, int nstype = 0)
        C_ARGS: s_fileno (fh_or_fd, 0), nstype

int
pivot_root (SV *new_root, SV *old_root)
        CODE:
        RETVAL = syscall (SYS_pivot_root,
                          (const char *)SvPVbyte_nolen (new_root),
                          (const char *)SvPVbyte_nolen (old_root));
        OUTPUT: RETVAL

int
kcmp (IV pid1, IV pid2, IV type, UV idx1 = 0, UV idx2 = 0)

int
siocsifflags (char *ifname, U32 flags = IFF_UP)
        CODE:
{
        int saved_errno;
        struct ifreq ifr;
        int fd = socket (AF_INET, SOCK_DGRAM, 0);
        strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
        RETVAL = ioctl (fd, SIOCSIFFLAGS, &ifr);
        saved_errno = errno;
        close (fd);
        errno = saved_errno;
}
        OUTPUT: RETVAL

Revision:	1.7
Committed:	Sat Sep 3 23:56:10 2022 UTC (20 months, 2 weeks ago) by root
Branch:	MAIN
Changes since 1.6:	+14 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	#include "EXTERN.h"
2			#include "perl.h"
3			#include "XSUB.h"
4
5			#include <sys/errno.h>
6			#include <sys/mman.h>
7
8			#undef _GNU_SOURCE
9			#define _GNU_SOURCE
10			#include <sched.h>
11	root	1.3	#include <unistd.h>
12			#include <sys/syscall.h>
13
14	root	1.6	#include <sched.h>
15
16			#include <sys/ioctl.h>
17			#include <net/if.h>
18
19	root	1.7	#include <linux/nsfs.h>
20
21	root	1.4	#ifdef __has_include
22			#if !__has_include("linux/kcmp.h") // use "" as GCC wrongly expands macros
23			#undef SYS_kcmp
24			#endif
25			#endif
26
27	root	1.3	#ifdef SYS_kcmp
28	root	1.4	#include "linux/kcmp.h"
29	root	1.3	#define kcmp(pid1,pid2,type,idx1,idx2) \
30			syscall (SYS_kcmp, (pid_t)pid1, (pid_t)pid2, \
31			(int)type, (unsigned long)idx1, (unsigned long)idx2)
32			#else
33			#define kcmp(pid1,pid2,type,idx1,idx2) \
34			(errno = ENOSYS, -1)
35			#endif
36	root	1.1
37	root	1.2	/* from schmorp.h */
38			static int
39			s_fileno (SV *fh, int wr)
40			{
41			dTHX;
42			SvGETMAGIC (fh);
43
44			if (SvROK (fh))
45			{
46			fh = SvRV (fh);
47			SvGETMAGIC (fh);
48			}
49
50			if (SvTYPE (fh) == SVt_PVGV)
51			return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));
52
53			if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
54			return SvIV (fh);
55
56			return -1;
57			}
58
59	root	1.1	static int
60			clone_cb (void *arg)
61			{
62			dSP;
63
64			PUSHMARK (SP);
65
66			PUTBACK;
67			int count = call_sv (sv_2mortal ((SV *)arg), G_SCALAR);
68			SPAGAIN;
69			int retval = count ? SvIV (POPs) : 0;
70			PUTBACK;
71
72			return retval;
73			}
74
75			MODULE = Linux::Clone PACKAGE = Linux::Clone
76
77			PROTOTYPES: ENABLE
78
79			BOOT:
80			HV *stash = gv_stashpv ("Linux::Clone", 1);
81
82			static const struct {
83			const char *name;
84			IV iv;
85			} *civ, const_iv[] = {
86	root	1.4	# define const_iv(name) { # name, (IV)name },
87			# define const_iv_clone(name) { # name, (IV) CLONE_ ## name },
88	root	1.6	# ifdef CSIGNAL
89			const_iv (CSIGNAL)
90			# endif
91	root	1.1	# ifdef CLONE_FILES
92	root	1.4	const_iv_clone (FILES)
93	root	1.1	# endif
94			# ifdef CLONE_FS
95	root	1.4	const_iv_clone (FS)
96	root	1.1	# endif
97			# ifdef CLONE_NEWNS
98	root	1.4	const_iv_clone (NEWNS)
99	root	1.1	# endif
100			# ifdef CLONE_VM
101	root	1.4	const_iv_clone (VM)
102	root	1.1	# endif
103			# ifdef CLONE_THREAD
104	root	1.4	const_iv_clone (THREAD)
105	root	1.1	# endif
106			# ifdef CLONE_SIGHAND
107	root	1.4	const_iv_clone (SIGHAND)
108	root	1.1	# endif
109			# ifdef CLONE_SYSVSEM
110	root	1.4	const_iv_clone (SYSVSEM)
111	root	1.1	# endif
112			# ifdef CLONE_NEWUTS
113	root	1.4	const_iv_clone (NEWUTS)
114	root	1.1	# endif
115			# ifdef CLONE_NEWIPC
116	root	1.4	const_iv_clone (NEWIPC)
117	root	1.1	# endif
118			# ifdef CLONE_NEWNET
119	root	1.4	const_iv_clone (NEWNET)
120	root	1.1	# endif
121			# ifdef CLONE_PTRACE
122	root	1.4	const_iv_clone (PTRACE)
123	root	1.1	# endif
124			# ifdef CLONE_VFORK
125	root	1.4	const_iv_clone (VFORK)
126	root	1.1	# endif
127			# ifdef CLONE_SETTLS
128	root	1.4	const_iv_clone (SETTLS)
129	root	1.1	# endif
130			# ifdef CLONE_PARENT_SETTID
131	root	1.4	const_iv_clone (PARENT_SETTID)
132	root	1.1	# endif
133			# ifdef CLONE_CHILD_CLEARTID
134	root	1.4	const_iv_clone (CHILD_CLEARTID)
135	root	1.1	# endif
136			# ifdef CLONE_DETACHED
137	root	1.4	const_iv_clone (DETACHED)
138	root	1.1	# endif
139			# ifdef CLONE_UNTRACED
140	root	1.4	const_iv_clone (UNTRACED)
141	root	1.1	# endif
142			# ifdef CLONE_CHILD_SETTID
143	root	1.4	const_iv_clone (CHILD_SETTID)
144	root	1.1	# endif
145			# ifdef CLONE_NEWUSER
146	root	1.4	const_iv_clone (NEWUSER)
147	root	1.1	# endif
148			# ifdef CLONE_NEWPID
149	root	1.4	const_iv_clone (NEWPID)
150	root	1.1	# endif
151			# ifdef CLONE_IO
152	root	1.4	const_iv_clone (IO)
153	root	1.1	# endif
154	root	1.2	# ifdef CLONE_NEWCGROUP
155	root	1.4	const_iv_clone (NEWCGROUP)
156	root	1.3	# endif
157	root	1.5	# ifdef CLONE_PIDFD
158			const_iv_clone (PIDFD)
159			# endif
160	root	1.3	# ifdef SYS_kcmp
161			const_iv (KCMP_FILE)
162			const_iv (KCMP_VM)
163			const_iv (KCMP_FILES)
164			const_iv (KCMP_FS)
165			const_iv (KCMP_SIGHAND)
166			const_iv (KCMP_IO)
167			const_iv (KCMP_SYSVSEM)
168			const_iv (KCMP_FILE)
169	root	1.2	# endif
170	root	1.7	# ifdef NS_GET_USERNS
171			const_iv (NS_GET_USERNS)
172			# endif
173			# ifdef NS_GET_PARENT
174			const_iv (NS_GET_PARENT)
175			# endif
176			# ifdef NS_GET_NSTYPE
177			const_iv (NS_GET_NSTYPE)
178			# endif
179			# ifdef NS_OWNER_UID
180			const_iv (NS_OWNER_UID
181			# endif
182	root	1.1	};
183
184			for (civ = const_iv + sizeof (const_iv) / sizeof (const_iv [0]); civ > const_iv; civ--)
185			newCONSTSUB (stash, (char *)civ[-1].name, newSViv (civ[-1].iv));
186
187			int
188			clone (SV sub, IV stacksize, int flags, SV ptid = 0, SV *tls = &PL_sv_undef)
189			CODE:
190			{
191	root	1.2	if (!stacksize)
192	root	1.1	stacksize = 4 << 20;
193
194			pid_t ptid_;
195			char *stack_ptr = mmap (0, stacksize, PROT_EXEC \| PROT_READ \| PROT_WRITE, MAP_PRIVATE \| MAP_ANONYMOUS \| MAP_GROWSDOWN \| MAP_STACK, -1, 0);
196
197			#ifndef __hppa
198			stack_ptr += stacksize - 16; /* be safe and put the sp at 16 bytes below the end */
199			#endif
200
201			RETVAL = -1;
202			if (stack_ptr != (void *)-1)
203			{
204			SV *my_sub = newSVsv (sub);
205
206			RETVAL = clone (clone_cb, (void )stack_ptr, flags, (void )my_sub, &ptid, SvOK (tls) ? SvPV_nolen (tls) : 0, 0);
207
208			if (ptid) sv_setiv (ptid, (IV)ptid_);
209
210			if ((flags & (CLONE_VM \| CLONE_VFORK)) != CLONE_VM)
211			{
212			int old_errno = errno;
213			munmap (stack_ptr, stacksize);
214			errno = old_errno;
215			}
216			}
217			}
218	root	1.6	OUTPUT: RETVAL
219	root	1.1
220	root	1.2	int
221			unshare (int flags)
222
223			int
224			setns (SV *fh_or_fd, int nstype = 0)
225			C_ARGS: s_fileno (fh_or_fd, 0), nstype
226	root	1.3
227			int
228			pivot_root (SV new_root, SV old_root)
229			CODE:
230			RETVAL = syscall (SYS_pivot_root,
231			(const char *)SvPVbyte_nolen (new_root),
232			(const char *)SvPVbyte_nolen (old_root));
233	root	1.6	OUTPUT: RETVAL
234	root	1.3
235			int
236			kcmp (IV pid1, IV pid2, IV type, UV idx1 = 0, UV idx2 = 0)
237
238	root	1.6	int
239			siocsifflags (char *ifname, U32 flags = IFF_UP)
240			CODE:
241			{
242			int saved_errno;
243			struct ifreq ifr;
244			int fd = socket (AF_INET, SOCK_DGRAM, 0);
245			strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
246			RETVAL = ioctl (fd, SIOCSIFFLAGS, &ifr);
247			saved_errno = errno;
248			close (fd);
249			errno = saved_errno;
250			}
251			OUTPUT: RETVAL
252