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>

#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
  };

  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:	1.6
Committed:	Sat Sep 3 23:47:02 2022 UTC (20 months, 2 weeks ago) by root
Branch:	MAIN
Changes since 1.5:	+25 -4 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	1.4	#ifdef __has_include
20			#if !__has_include("linux/kcmp.h") // use "" as GCC wrongly expands macros
21			#undef SYS_kcmp
22			#endif
23			#endif
24
25	root	1.3	#ifdef SYS_kcmp
26	root	1.4	#include "linux/kcmp.h"
27	root	1.3	#define kcmp(pid1,pid2,type,idx1,idx2) \
28			syscall (SYS_kcmp, (pid_t)pid1, (pid_t)pid2, \
29			(int)type, (unsigned long)idx1, (unsigned long)idx2)
30			#else
31			#define kcmp(pid1,pid2,type,idx1,idx2) \
32			(errno = ENOSYS, -1)
33			#endif
34	root	1.1
35	root	1.2	/* from schmorp.h */
36			static int
37			s_fileno (SV *fh, int wr)
38			{
39			dTHX;
40			SvGETMAGIC (fh);
41
42			if (SvROK (fh))
43			{
44			fh = SvRV (fh);
45			SvGETMAGIC (fh);
46			}
47
48			if (SvTYPE (fh) == SVt_PVGV)
49			return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));
50
51			if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
52			return SvIV (fh);
53
54			return -1;
55			}
56
57	root	1.1	static int
58			clone_cb (void *arg)
59			{
60			dSP;
61
62			PUSHMARK (SP);
63
64			PUTBACK;
65			int count = call_sv (sv_2mortal ((SV *)arg), G_SCALAR);
66			SPAGAIN;
67			int retval = count ? SvIV (POPs) : 0;
68			PUTBACK;
69
70			return retval;
71			}
72
73			MODULE = Linux::Clone PACKAGE = Linux::Clone
74
75			PROTOTYPES: ENABLE
76
77			BOOT:
78			HV *stash = gv_stashpv ("Linux::Clone", 1);
79
80			static const struct {
81			const char *name;
82			IV iv;
83			} *civ, const_iv[] = {
84	root	1.4	# define const_iv(name) { # name, (IV)name },
85			# define const_iv_clone(name) { # name, (IV) CLONE_ ## name },
86	root	1.6	# ifdef CSIGNAL
87			const_iv (CSIGNAL)
88			# endif
89	root	1.1	# ifdef CLONE_FILES
90	root	1.4	const_iv_clone (FILES)
91	root	1.1	# endif
92			# ifdef CLONE_FS
93	root	1.4	const_iv_clone (FS)
94	root	1.1	# endif
95			# ifdef CLONE_NEWNS
96	root	1.4	const_iv_clone (NEWNS)
97	root	1.1	# endif
98			# ifdef CLONE_VM
99	root	1.4	const_iv_clone (VM)
100	root	1.1	# endif
101			# ifdef CLONE_THREAD
102	root	1.4	const_iv_clone (THREAD)
103	root	1.1	# endif
104			# ifdef CLONE_SIGHAND
105	root	1.4	const_iv_clone (SIGHAND)
106	root	1.1	# endif
107			# ifdef CLONE_SYSVSEM
108	root	1.4	const_iv_clone (SYSVSEM)
109	root	1.1	# endif
110			# ifdef CLONE_NEWUTS
111	root	1.4	const_iv_clone (NEWUTS)
112	root	1.1	# endif
113			# ifdef CLONE_NEWIPC
114	root	1.4	const_iv_clone (NEWIPC)
115	root	1.1	# endif
116			# ifdef CLONE_NEWNET
117	root	1.4	const_iv_clone (NEWNET)
118	root	1.1	# endif
119			# ifdef CLONE_PTRACE
120	root	1.4	const_iv_clone (PTRACE)
121	root	1.1	# endif
122			# ifdef CLONE_VFORK
123	root	1.4	const_iv_clone (VFORK)
124	root	1.1	# endif
125			# ifdef CLONE_SETTLS
126	root	1.4	const_iv_clone (SETTLS)
127	root	1.1	# endif
128			# ifdef CLONE_PARENT_SETTID
129	root	1.4	const_iv_clone (PARENT_SETTID)
130	root	1.1	# endif
131			# ifdef CLONE_CHILD_CLEARTID
132	root	1.4	const_iv_clone (CHILD_CLEARTID)
133	root	1.1	# endif
134			# ifdef CLONE_DETACHED
135	root	1.4	const_iv_clone (DETACHED)
136	root	1.1	# endif
137			# ifdef CLONE_UNTRACED
138	root	1.4	const_iv_clone (UNTRACED)
139	root	1.1	# endif
140			# ifdef CLONE_CHILD_SETTID
141	root	1.4	const_iv_clone (CHILD_SETTID)
142	root	1.1	# endif
143			# ifdef CLONE_NEWUSER
144	root	1.4	const_iv_clone (NEWUSER)
145	root	1.1	# endif
146			# ifdef CLONE_NEWPID
147	root	1.4	const_iv_clone (NEWPID)
148	root	1.1	# endif
149			# ifdef CLONE_IO
150	root	1.4	const_iv_clone (IO)
151	root	1.1	# endif
152	root	1.2	# ifdef CLONE_NEWCGROUP
153	root	1.4	const_iv_clone (NEWCGROUP)
154	root	1.3	# endif
155	root	1.5	# ifdef CLONE_PIDFD
156			const_iv_clone (PIDFD)
157			# endif
158	root	1.3	# ifdef SYS_kcmp
159			const_iv (KCMP_FILE)
160			const_iv (KCMP_VM)
161			const_iv (KCMP_FILES)
162			const_iv (KCMP_FS)
163			const_iv (KCMP_SIGHAND)
164			const_iv (KCMP_IO)
165			const_iv (KCMP_SYSVSEM)
166			const_iv (KCMP_FILE)
167	root	1.2	# endif
168	root	1.1	};
169
170			for (civ = const_iv + sizeof (const_iv) / sizeof (const_iv [0]); civ > const_iv; civ--)
171			newCONSTSUB (stash, (char *)civ[-1].name, newSViv (civ[-1].iv));
172
173			int
174			clone (SV sub, IV stacksize, int flags, SV ptid = 0, SV *tls = &PL_sv_undef)
175			CODE:
176			{
177	root	1.2	if (!stacksize)
178	root	1.1	stacksize = 4 << 20;
179
180			pid_t ptid_;
181			char *stack_ptr = mmap (0, stacksize, PROT_EXEC \| PROT_READ \| PROT_WRITE, MAP_PRIVATE \| MAP_ANONYMOUS \| MAP_GROWSDOWN \| MAP_STACK, -1, 0);
182
183			#ifndef __hppa
184			stack_ptr += stacksize - 16; /* be safe and put the sp at 16 bytes below the end */
185			#endif
186
187			RETVAL = -1;
188			if (stack_ptr != (void *)-1)
189			{
190			SV *my_sub = newSVsv (sub);
191
192			RETVAL = clone (clone_cb, (void )stack_ptr, flags, (void )my_sub, &ptid, SvOK (tls) ? SvPV_nolen (tls) : 0, 0);
193
194			if (ptid) sv_setiv (ptid, (IV)ptid_);
195
196			if ((flags & (CLONE_VM \| CLONE_VFORK)) != CLONE_VM)
197			{
198			int old_errno = errno;
199			munmap (stack_ptr, stacksize);
200			errno = old_errno;
201			}
202			}
203			}
204	root	1.6	OUTPUT: RETVAL
205	root	1.1
206	root	1.2	int
207			unshare (int flags)
208
209			int
210			setns (SV *fh_or_fd, int nstype = 0)
211			C_ARGS: s_fileno (fh_or_fd, 0), nstype
212	root	1.3
213			int
214			pivot_root (SV new_root, SV old_root)
215			CODE:
216			RETVAL = syscall (SYS_pivot_root,
217			(const char *)SvPVbyte_nolen (new_root),
218			(const char *)SvPVbyte_nolen (old_root));
219	root	1.6	OUTPUT: RETVAL
220	root	1.3
221			int
222			kcmp (IV pid1, IV pid2, IV type, UV idx1 = 0, UV idx2 = 0)
223
224	root	1.6	int
225			siocsifflags (char *ifname, U32 flags = IFF_UP)
226			CODE:
227			{
228			int saved_errno;
229			struct ifreq ifr;
230			int fd = socket (AF_INET, SOCK_DGRAM, 0);
231			strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
232			RETVAL = ioctl (fd, SIOCSIFFLAGS, &ifr);
233			saved_errno = errno;
234			close (fd);
235			errno = saved_errno;
236			}
237			OUTPUT: RETVAL
238