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      1 #include "defs.h"
      2 
      3 /* defines copied from linux/sched.h since we can't include that
      4  * ourselves (it conflicts with *lots* of libc includes)
      5  */
      6 #define CSIGNAL         0x000000ff      /* signal mask to be sent at exit */
      7 #define CLONE_VM        0x00000100      /* set if VM shared between processes */
      8 #define CLONE_FS        0x00000200      /* set if fs info shared between processes */
      9 #define CLONE_FILES     0x00000400      /* set if open files shared between processes */
     10 #define CLONE_SIGHAND   0x00000800      /* set if signal handlers shared */
     11 #define CLONE_IDLETASK  0x00001000      /* kernel-only flag */
     12 #define CLONE_PTRACE    0x00002000      /* set if we want to let tracing continue on the child too */
     13 #define CLONE_VFORK     0x00004000      /* set if the parent wants the child to wake it up on mm_release */
     14 #define CLONE_PARENT    0x00008000      /* set if we want to have the same parent as the cloner */
     15 #define CLONE_THREAD	0x00010000	/* Same thread group? */
     16 #define CLONE_NEWNS	0x00020000	/* New namespace group? */
     17 #define CLONE_SYSVSEM	0x00040000	/* share system V SEM_UNDO semantics */
     18 #define CLONE_SETTLS	0x00080000	/* create a new TLS for the child */
     19 #define CLONE_PARENT_SETTID	0x00100000	/* set the TID in the parent */
     20 #define CLONE_CHILD_CLEARTID	0x00200000	/* clear the TID in the child */
     21 #define CLONE_UNTRACED		0x00800000	/* set if the tracing process can't force CLONE_PTRACE on this clone */
     22 #define CLONE_CHILD_SETTID	0x01000000	/* set the TID in the child */
     23 #define CLONE_STOPPED		0x02000000	/* Start in stopped state */
     24 #define CLONE_NEWUTS		0x04000000	/* New utsname group? */
     25 #define CLONE_NEWIPC		0x08000000	/* New ipcs */
     26 #define CLONE_NEWUSER		0x10000000	/* New user namespace */
     27 #define CLONE_NEWPID		0x20000000	/* New pid namespace */
     28 #define CLONE_NEWNET		0x40000000	/* New network namespace */
     29 #define CLONE_IO		0x80000000	/* Clone io context */
     30 
     31 #include "xlat/clone_flags.h"
     32 
     33 #if defined IA64
     34 # define ARG_FLAGS	0
     35 # define ARG_STACK	1
     36 # define ARG_STACKSIZE	(tcp->scno == SYS_clone2 ? 2 : -1)
     37 # define ARG_PTID	(tcp->scno == SYS_clone2 ? 3 : 2)
     38 # define ARG_CTID	(tcp->scno == SYS_clone2 ? 4 : 3)
     39 # define ARG_TLS	(tcp->scno == SYS_clone2 ? 5 : 4)
     40 #elif defined S390 || defined S390X || defined CRISV10 || defined CRISV32
     41 # define ARG_STACK	0
     42 # define ARG_FLAGS	1
     43 # define ARG_PTID	2
     44 # define ARG_CTID	3
     45 # define ARG_TLS	4
     46 #elif defined X86_64 || defined X32
     47 /* x86 personality processes have the last two arguments flipped. */
     48 # define ARG_FLAGS	0
     49 # define ARG_STACK	1
     50 # define ARG_PTID	2
     51 # define ARG_CTID	((current_personality != 1) ? 3 : 4)
     52 # define ARG_TLS	((current_personality != 1) ? 4 : 3)
     53 #elif defined ALPHA || defined TILE || defined OR1K
     54 # define ARG_FLAGS	0
     55 # define ARG_STACK	1
     56 # define ARG_PTID	2
     57 # define ARG_CTID	3
     58 # define ARG_TLS	4
     59 #else
     60 # define ARG_FLAGS	0
     61 # define ARG_STACK	1
     62 # define ARG_PTID	2
     63 # define ARG_TLS	3
     64 # define ARG_CTID	4
     65 #endif
     66 
     67 #if defined I386 || defined X86_64 || defined X32
     68 extern void print_user_desc(struct tcb *, long);
     69 #endif /* I386 || X86_64 || X32 */
     70 
     71 SYS_FUNC(clone)
     72 {
     73 	if (exiting(tcp)) {
     74 		const char *sep = "|";
     75 		unsigned long flags = tcp->u_arg[ARG_FLAGS];
     76 		tprintf("child_stack=%#lx, ", tcp->u_arg[ARG_STACK]);
     77 #ifdef ARG_STACKSIZE
     78 		if (ARG_STACKSIZE != -1)
     79 			tprintf("stack_size=%#lx, ",
     80 				tcp->u_arg[ARG_STACKSIZE]);
     81 #endif
     82 		tprints("flags=");
     83 		if (!printflags(clone_flags, flags &~ CSIGNAL, NULL))
     84 			sep = "";
     85 		if ((flags & CSIGNAL) != 0)
     86 			tprintf("%s%s", sep, signame(flags & CSIGNAL));
     87 		if ((flags & (CLONE_PARENT_SETTID|CLONE_CHILD_SETTID
     88 			      |CLONE_CHILD_CLEARTID|CLONE_SETTLS)) == 0)
     89 			return 0;
     90 		if (flags & CLONE_PARENT_SETTID)
     91 			tprintf(", parent_tidptr=%#lx", tcp->u_arg[ARG_PTID]);
     92 		if (flags & CLONE_SETTLS) {
     93 #if defined I386 || defined X86_64 || defined X32
     94 # ifndef I386
     95 			if (current_personality == 1)
     96 # endif
     97 			{
     98 				tprints(", tls=");
     99 				print_user_desc(tcp, tcp->u_arg[ARG_TLS]);
    100 			}
    101 # ifndef I386
    102 			else
    103 # endif
    104 #endif /* I386 || X86_64 || X32 */
    105 				tprintf(", tls=%#lx", tcp->u_arg[ARG_TLS]);
    106 		}
    107 		if (flags & (CLONE_CHILD_SETTID|CLONE_CHILD_CLEARTID))
    108 			tprintf(", child_tidptr=%#lx", tcp->u_arg[ARG_CTID]);
    109 	}
    110 	/* TODO on syscall entry:
    111 	 * We can clear CLONE_PTRACE here since it is an ancient hack
    112 	 * to allow us to catch children, and we use another hack for that.
    113 	 * But CLONE_PTRACE can conceivably be used by malicious programs
    114 	 * to subvert us. By clearing this bit, we can defend against it:
    115 	 * in untraced execution, CLONE_PTRACE should have no effect.
    116 	 *
    117 	 * We can also clear CLONE_UNTRACED, since it allows to start
    118 	 * children outside of our control. At the moment
    119 	 * I'm trying to figure out whether there is a *legitimate*
    120 	 * use of this flag which we should respect.
    121 	 */
    122 	return 0;
    123 }
    124 
    125 SYS_FUNC(setns)
    126 {
    127 	if (entering(tcp)) {
    128 		printfd(tcp, tcp->u_arg[0]);
    129 		tprints(", ");
    130 		printflags(clone_flags, tcp->u_arg[1], "CLONE_???");
    131 	}
    132 	return 0;
    133 }
    134 
    135 SYS_FUNC(unshare)
    136 {
    137 	if (entering(tcp))
    138 		printflags(clone_flags, tcp->u_arg[0], "CLONE_???");
    139 	return 0;
    140 }
    141 
    142 SYS_FUNC(fork)
    143 {
    144 	if (exiting(tcp))
    145 		return RVAL_UDECIMAL;
    146 	return 0;
    147 }
    148