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>

#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 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
  };

  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)

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