/* * Call a system call which takes a pointer to the user args struct and * a pointer to the return values. This is a bit slower than the standard * C arg-passing method in some cases. */ int64_t syscall_ap(void) { uint_t error; struct sysent *callp; rval_t rval; kthread_t *t = curthread; klwp_t *lwp = ttolwp(t); struct regs *rp = lwptoregs(lwp); callp = LWP_GETSYSENT(lwp) + t->t_sysnum; #if defined(__amd64) /* * If the arguments don't fit in registers %rdi-%r9, make sure they * have been copied to the lwp_arg array. */ if (callp->sy_narg > 6 && save_syscall_args()) return ((int64_t)set_errno(EFAULT)); #endif rval.r_val1 = 0; rval.r_val2 = rp->r_r1; lwp->lwp_error = 0; /* for old drivers */ error = (*(callp->sy_call))(lwp->lwp_ap, &rval); if (error) return ((longlong_t)set_errno(error)); return (rval.r_vals); }
/* * Call a system call which takes a pointer to the user args struct and * a pointer to the return values. This is a bit slower than the standard * C arg-passing method in some cases. */ int64_t syscall_ap() { uint_t error; struct sysent *callp; rval_t rval; klwp_t *lwp = ttolwp(curthread); struct regs *rp = lwptoregs(lwp); callp = LWP_GETSYSENT(lwp) + curthread->t_sysnum; /* * If the arguments don't fit in registers %o0 - o5, make sure they * have been copied to the lwp_arg array. */ if (callp->sy_narg > 6 && save_syscall_args()) return ((int64_t)set_errno(EFAULT)); rval.r_val1 = 0; rval.r_val2 = (int)rp->r_o1; lwp->lwp_error = 0; /* for old drivers */ error = (*(callp->sy_call))(lwp->lwp_ap, &rval); if (error) return ((int64_t)set_errno(error)); return (rval.r_vals); }
/* * Handle indirect system calls. * This interface should be deprecated. The library can handle * this more efficiently, but keep this implementation for old binaries. * * XX64 Needs some work. */ int64_t indir(int code, long a0, long a1, long a2, long a3, long a4) { klwp_t *lwp = ttolwp(curthread); struct sysent *callp; if (code <= 0 || code >= NSYSCALL) return (nosys()); ASSERT(lwp->lwp_ap != NULL); curthread->t_sysnum = code; callp = LWP_GETSYSENT(lwp) + code; /* * Handle argument setup, unless already done in pre_syscall(). */ if (callp->sy_narg > 5) { if (save_syscall_args()) /* move args to LWP array */ return ((int64_t)set_errno(EFAULT)); } else if (!lwp->lwp_argsaved) { long *ap; ap = lwp->lwp_ap; /* args haven't been saved */ lwp->lwp_ap = ap + 1; /* advance arg pointer */ curthread->t_post_sys = 1; /* so lwp_ap will be reset */ } return ((*callp->sy_callc)(a0, a1, a2, a3, a4, lwp->lwp_arg[5])); }
/* * Post-syscall processing. Perform abnormal system call completion * actions such as /proc tracing, profiling, signals, preemption, etc. * * This routine is called only if t_post_sys, t_sig_check, or t_astflag is set. * Any condition requiring pre-syscall handling must set one of these. * If the condition is persistent, this routine will repost t_post_sys. */ void post_syscall(long rval1, long rval2) { kthread_t *t = curthread; klwp_t *lwp = ttolwp(t); proc_t *p = ttoproc(t); struct regs *rp = lwptoregs(lwp); uint_t error; uint_t code = t->t_sysnum; int repost = 0; int proc_stop = 0; /* non-zero if stopping */ int sigprof = 0; /* non-zero if sending SIGPROF */ t->t_post_sys = 0; error = lwp->lwp_errno; /* * Code can be zero if this is a new LWP returning after a forkall(), * other than the one which matches the one in the parent which called * forkall(). In these LWPs, skip most of post-syscall activity. */ if (code == 0) goto sig_check; /* * If the trace flag is set, mark the lwp to take a single-step trap * on return to user level (below). The x86 lcall interface and * sysenter has already done this, and turned off the flag, but * amd64 syscall interface has not. */ if (rp->r_ps & PS_T) { lwp->lwp_pcb.pcb_flags |= DEBUG_PENDING; rp->r_ps &= ~PS_T; aston(curthread); } #ifdef C2_AUDIT if (audit_active) { /* put out audit record for this syscall */ rval_t rval; /* XX64 -- truncation of 64-bit return values? */ rval.r_val1 = (int)rval1; rval.r_val2 = (int)rval2; audit_finish(T_SYSCALL, code, error, &rval); repost = 1; } #endif /* C2_AUDIT */ if (curthread->t_pdmsg != NULL) { char *m = curthread->t_pdmsg; uprintf("%s", m); kmem_free(m, strlen(m) + 1); curthread->t_pdmsg = NULL; } /* * If we're going to stop for /proc tracing, set the flag and * save the arguments so that the return values don't smash them. */ if (PTOU(p)->u_systrap) { if (prismember(&PTOU(p)->u_exitmask, code)) { if (lwp_getdatamodel(lwp) == DATAMODEL_LP64) (void) save_syscall_args(); proc_stop = 1; } repost = 1; } /* * Similarly check to see if SIGPROF might be sent. */ if (curthread->t_rprof != NULL && curthread->t_rprof->rp_anystate != 0) { if (lwp_getdatamodel(lwp) == DATAMODEL_LP64) (void) save_syscall_args(); sigprof = 1; } if (lwp->lwp_eosys == NORMALRETURN) { if (error == 0) { #ifdef SYSCALLTRACE if (syscalltrace) { mutex_enter(&systrace_lock); printf( "%d: r_val1=0x%lx, r_val2=0x%lx, id 0x%p\n", p->p_pid, rval1, rval2, curthread); mutex_exit(&systrace_lock); } #endif /* SYSCALLTRACE */ rp->r_ps &= ~PS_C; rp->r_r0 = rval1; rp->r_r1 = rval2; } else { int sig; #ifdef SYSCALLTRACE if (syscalltrace) { mutex_enter(&systrace_lock); printf("%d: error=%d, id 0x%p\n", p->p_pid, error, curthread); mutex_exit(&systrace_lock); } #endif /* SYSCALLTRACE */ if (error == EINTR && t->t_activefd.a_stale) error = EBADF; if (error == EINTR && (sig = lwp->lwp_cursig) != 0 && sigismember(&PTOU(p)->u_sigrestart, sig) && PTOU(p)->u_signal[sig - 1] != SIG_DFL && PTOU(p)->u_signal[sig - 1] != SIG_IGN) error = ERESTART; rp->r_r0 = error; rp->r_ps |= PS_C; } } /* * From the proc(4) manual page: * When exit from a system call is being traced, the traced process * stops on completion of the system call just prior to checking for * signals and returning to user level. At this point all return * values have been stored into the traced process's saved registers. */ if (proc_stop) { mutex_enter(&p->p_lock); if (PTOU(p)->u_systrap && prismember(&PTOU(p)->u_exitmask, code)) stop(PR_SYSEXIT, code); mutex_exit(&p->p_lock); } /* * If we are the parent returning from a successful * vfork, wait for the child to exec or exit. * This code must be here and not in the bowels of the system * so that /proc can intercept exit from vfork in a timely way. */ if (code == SYS_vfork && rp->r_r1 == 0 && error == 0) vfwait((pid_t)rval1); /* * If profiling is active, bill the current PC in user-land * and keep reposting until profiling is disabled. */ if (p->p_prof.pr_scale) { if (lwp->lwp_oweupc) profil_tick(rp->r_pc); repost = 1; } sig_check: /* * Reset flag for next time. * We must do this after stopping on PR_SYSEXIT * because /proc uses the information in lwp_eosys. */ lwp->lwp_eosys = NORMALRETURN; clear_stale_fd(); t->t_flag &= ~T_FORKALL; if (t->t_astflag | t->t_sig_check) { /* * Turn off the AST flag before checking all the conditions that * may have caused an AST. This flag is on whenever a signal or * unusual condition should be handled after the next trap or * syscall. */ astoff(t); /* * If a single-step trap occurred on a syscall (see trap()) * recognize it now. Do this before checking for signals * because deferred_singlestep_trap() may generate a SIGTRAP to * the LWP or may otherwise mark the LWP to call issig(FORREAL). */ if (lwp->lwp_pcb.pcb_flags & DEBUG_PENDING) deferred_singlestep_trap((caddr_t)rp->r_pc); t->t_sig_check = 0; /* * The following check is legal for the following reasons: * 1) The thread we are checking, is ourselves, so there is * no way the proc can go away. * 2) The only time we need to be protected by the * lock is if the binding is changed. * * Note we will still take the lock and check the binding * if the condition was true without the lock held. This * prevents lock contention among threads owned by the * same proc. */ if (curthread->t_proc_flag & TP_CHANGEBIND) { mutex_enter(&p->p_lock); if (curthread->t_proc_flag & TP_CHANGEBIND) { timer_lwpbind(); curthread->t_proc_flag &= ~TP_CHANGEBIND; } mutex_exit(&p->p_lock); } /* * for kaio requests on the special kaio poll queue, * copyout their results to user memory. */ if (p->p_aio) aio_cleanup(0); /* * If this LWP was asked to hold, call holdlwp(), which will * stop. holdlwps() sets this up and calls pokelwps() which * sets the AST flag. * * Also check TP_EXITLWP, since this is used by fresh new LWPs * through lwp_rtt(). That flag is set if the lwp_create(2) * syscall failed after creating the LWP. */ if (ISHOLD(p) || (t->t_proc_flag & TP_EXITLWP)) holdlwp(); /* * All code that sets signals and makes ISSIG_PENDING * evaluate true must set t_sig_check afterwards. */ if (ISSIG_PENDING(t, lwp, p)) { if (issig(FORREAL)) psig(); t->t_sig_check = 1; /* recheck next time */ } if (sigprof) { realsigprof(code, error); t->t_sig_check = 1; /* recheck next time */ } /* * If a performance counter overflow interrupt was * delivered *during* the syscall, then re-enable the * AST so that we take a trip through trap() to cause * the SIGEMT to be delivered. */ if (lwp->lwp_pcb.pcb_flags & CPC_OVERFLOW) aston(t); /* * /proc can't enable/disable the trace bit itself * because that could race with the call gate used by * system calls via "lcall". If that happened, an * invalid EFLAGS would result. prstep()/prnostep() * therefore schedule an AST for the purpose. */ if (lwp->lwp_pcb.pcb_flags & REQUEST_STEP) { lwp->lwp_pcb.pcb_flags &= ~REQUEST_STEP; rp->r_ps |= PS_T; } if (lwp->lwp_pcb.pcb_flags & REQUEST_NOSTEP) { lwp->lwp_pcb.pcb_flags &= ~REQUEST_NOSTEP; rp->r_ps &= ~PS_T; } } lwp->lwp_errno = 0; /* clear error for next time */ #ifndef NPROBE /* Kernel probe */ if (tnf_tracing_active) { TNF_PROBE_3(syscall_end, "syscall thread", /* CSTYLED */, tnf_long, rval1, rval1, tnf_long, rval2, rval2, tnf_long, errno, (long)error); repost = 1; } #endif /* NPROBE */ /* * Set state to LWP_USER here so preempt won't give us a kernel * priority if it occurs after this point. Call CL_TRAPRET() to * restore the user-level priority. * * It is important that no locks (other than spinlocks) be entered * after this point before returning to user mode (unless lwp_state * is set back to LWP_SYS). * * XXX Sampled times past this point are charged to the user. */ lwp->lwp_state = LWP_USER; if (t->t_trapret) { t->t_trapret = 0; thread_lock(t); CL_TRAPRET(t); thread_unlock(t); } if (CPU->cpu_runrun) preempt(); lwp->lwp_errno = 0; /* clear error for next time */ /* * The thread lock must be held in order to clear sysnum and reset * lwp_ap atomically with respect to other threads in the system that * may be looking at the args via lwp_ap from get_syscall_args(). */ thread_lock(t); t->t_sysnum = 0; /* no longer in a system call */ if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) { #if defined(_LP64) /* * In case the args were copied to the lwp, reset the * pointer so the next syscall will have the right * lwp_ap pointer. */ lwp->lwp_ap = (long *)&rp->r_rdi; } else { #endif lwp->lwp_ap = NULL; /* reset on every syscall entry */ } thread_unlock(t); lwp->lwp_argsaved = 0; /* * If there was a continuing reason for post-syscall processing, * set the t_post_sys flag for the next system call. */ if (repost) t->t_post_sys = 1; /* * If there is a ustack registered for this lwp, and the stack rlimit * has been altered, read in the ustack. If the saved stack rlimit * matches the bounds of the ustack, update the ustack to reflect * the new rlimit. If the new stack rlimit is RLIM_INFINITY, disable * stack checking by setting the size to 0. */ if (lwp->lwp_ustack != 0 && lwp->lwp_old_stk_ctl != 0) { rlim64_t new_size; caddr_t top; stack_t stk; struct rlimit64 rl; mutex_enter(&p->p_lock); new_size = p->p_stk_ctl; top = p->p_usrstack; (void) rctl_rlimit_get(rctlproc_legacy[RLIMIT_STACK], p, &rl); mutex_exit(&p->p_lock); if (rl.rlim_cur == RLIM64_INFINITY) new_size = 0; if (copyin((stack_t *)lwp->lwp_ustack, &stk, sizeof (stack_t)) == 0 && (stk.ss_size == lwp->lwp_old_stk_ctl || stk.ss_size == 0) && stk.ss_sp == top - stk.ss_size) { stk.ss_sp = (void *)((uintptr_t)stk.ss_sp + stk.ss_size - (uintptr_t)new_size); stk.ss_size = new_size; (void) copyout(&stk, (stack_t *)lwp->lwp_ustack, sizeof (stack_t)); } lwp->lwp_old_stk_ctl = 0; } }
/* * Perform pre-system-call processing, including stopping for tracing, * auditing, etc. * * This routine is called only if the t_pre_sys flag is set. Any condition * requiring pre-syscall handling must set the t_pre_sys flag. If the * condition is persistent, this routine will repost t_pre_sys. */ int pre_syscall() { kthread_t *t = curthread; unsigned code = t->t_sysnum; klwp_t *lwp = ttolwp(t); proc_t *p = ttoproc(t); int repost; t->t_pre_sys = repost = 0; /* clear pre-syscall processing flag */ ASSERT(t->t_schedflag & TS_DONT_SWAP); #if defined(DEBUG) /* * On the i386 kernel, lwp_ap points at the piece of the thread * stack that we copy the users arguments into. * * On the amd64 kernel, the syscall arguments in the rdi..r9 * registers should be pointed at by lwp_ap. If the args need to * be copied so that those registers can be changed without losing * the ability to get the args for /proc, they can be saved by * save_syscall_args(), and lwp_ap will be restored by post_syscall(). */ if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) { #if defined(_LP64) ASSERT(lwp->lwp_ap == (long *)&lwptoregs(lwp)->r_rdi); } else { #endif ASSERT((caddr_t)lwp->lwp_ap > t->t_stkbase && (caddr_t)lwp->lwp_ap < t->t_stk); } #endif /* DEBUG */ /* * Make sure the thread is holding the latest credentials for the * process. The credentials in the process right now apply to this * thread for the entire system call. */ if (t->t_cred != p->p_cred) { cred_t *oldcred = t->t_cred; /* * DTrace accesses t_cred in probe context. t_cred must * always be either NULL, or point to a valid, allocated cred * structure. */ t->t_cred = crgetcred(); crfree(oldcred); } /* * From the proc(4) manual page: * When entry to a system call is being traced, the traced process * stops after having begun the call to the system but before the * system call arguments have been fetched from the process. */ if (PTOU(p)->u_systrap) { if (prismember(&PTOU(p)->u_entrymask, code)) { mutex_enter(&p->p_lock); /* * Recheck stop condition, now that lock is held. */ if (PTOU(p)->u_systrap && prismember(&PTOU(p)->u_entrymask, code)) { stop(PR_SYSENTRY, code); /* * /proc may have modified syscall args, * either in regs for amd64 or on ustack * for ia32. Either way, arrange to * copy them again, both for the syscall * handler and for other consumers in * post_syscall (like audit). Here, we * only do amd64, and just set lwp_ap * back to the kernel-entry stack copy; * the syscall ml code redoes * move-from-regs to set up for the * syscall handler after we return. For * ia32, save_syscall_args() below makes * an lwp_ap-accessible copy. */ #if defined(_LP64) if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE) { lwp->lwp_argsaved = 0; lwp->lwp_ap = (long *)&lwptoregs(lwp)->r_rdi; } #endif } mutex_exit(&p->p_lock); } repost = 1; } /* * ia32 kernel, or ia32 proc on amd64 kernel: keep args in * lwp_arg for post-syscall processing, regardless of whether * they might have been changed in /proc above. */ #if defined(_LP64) if (lwp_getdatamodel(lwp) != DATAMODEL_NATIVE) #endif (void) save_syscall_args(); if (lwp->lwp_sysabort) { /* * lwp_sysabort may have been set via /proc while the process * was stopped on PR_SYSENTRY. If so, abort the system call. * Override any error from the copyin() of the arguments. */ lwp->lwp_sysabort = 0; (void) set_errno(EINTR); /* forces post_sys */ t->t_pre_sys = 1; /* repost anyway */ return (1); /* don't do system call, return EINTR */ } #ifdef C2_AUDIT if (audit_active) { /* begin auditing for this syscall */ int error; if (error = audit_start(T_SYSCALL, code, 0, lwp)) { t->t_pre_sys = 1; /* repost anyway */ (void) set_errno(error); return (1); } repost = 1; } #endif /* C2_AUDIT */ #ifndef NPROBE /* Kernel probe */ if (tnf_tracing_active) { TNF_PROBE_1(syscall_start, "syscall thread", /* CSTYLED */, tnf_sysnum, sysnum, t->t_sysnum); t->t_post_sys = 1; /* make sure post_syscall runs */ repost = 1; } #endif /* NPROBE */ #ifdef SYSCALLTRACE if (syscalltrace) { int i; long *ap; char *cp; char *sysname; struct sysent *callp; if (code >= NSYSCALL) callp = &nosys_ent; /* nosys has no args */ else callp = LWP_GETSYSENT(lwp) + code; (void) save_syscall_args(); mutex_enter(&systrace_lock); printf("%d: ", p->p_pid); if (code >= NSYSCALL) printf("0x%x", code); else { sysname = mod_getsysname(code); printf("%s[0x%x/0x%p]", sysname == NULL ? "NULL" : sysname, code, callp->sy_callc); } cp = "("; for (i = 0, ap = lwp->lwp_ap; i < callp->sy_narg; i++, ap++) { printf("%s%lx", cp, *ap); cp = ", "; } if (i) printf(")"); printf(" %s id=0x%p\n", PTOU(p)->u_comm, curthread); mutex_exit(&systrace_lock); } #endif /* SYSCALLTRACE */ /* * If there was a continuing reason for pre-syscall processing, * set the t_pre_sys flag for the next system call. */ if (repost) t->t_pre_sys = 1; lwp->lwp_error = 0; /* for old drivers */ lwp->lwp_badpriv = PRIV_NONE; return (0); }
/* * System call to create an lwp. * * Notes on the LWP_DETACHED and LWP_DAEMON flags: * * A detached lwp (LWP_DETACHED) cannot be the specific target of * lwp_wait() (it is not joinable), but lwp_wait(0, ...) is required * to sleep until all non-daemon detached lwps have terminated before * returning EDEADLK because a detached lwp might create a non-detached lwp * that could then be returned by lwp_wait(0, ...). See also lwp_detach(). * * A daemon lwp (LWP_DAEMON) is a detached lwp that has the additional * property that it does not affect the termination condition of the * process: The last non-daemon lwp to call lwp_exit() causes the process * to exit and lwp_wait(0, ...) does not sleep waiting for daemon lwps * to terminate. See the block comment before lwp_wait(). */ int syslwp_create(ucontext_t *ucp, int flags, id_t *new_lwp) { klwp_t *lwp; proc_t *p = ttoproc(curthread); kthread_t *t; ucontext_t uc; #ifdef _SYSCALL32_IMPL ucontext32_t uc32; #endif /* _SYSCALL32_IMPL */ k_sigset_t sigmask; int tid; model_t model = get_udatamodel(); uintptr_t thrptr = 0; if (flags & ~(LWP_DAEMON|LWP_DETACHED|LWP_SUSPENDED)) return (set_errno(EINVAL)); /* * lwp_create() is disallowed for the /proc agent lwp. */ if (curthread == p->p_agenttp) return (set_errno(ENOTSUP)); if (model == DATAMODEL_NATIVE) { if (copyin(ucp, &uc, sizeof (ucontext_t))) return (set_errno(EFAULT)); sigutok(&uc.uc_sigmask, &sigmask); #if defined(__i386) /* * libc stashed thrptr into unused kernel %sp. * See setup_context() in libc. */ thrptr = (uint32_t)uc.uc_mcontext.gregs[ESP]; #endif } #ifdef _SYSCALL32_IMPL else { if (copyin(ucp, &uc32, sizeof (ucontext32_t))) return (set_errno(EFAULT)); sigutok(&uc32.uc_sigmask, &sigmask); #if defined(__sparc) ucontext_32ton(&uc32, &uc, NULL, NULL); #else /* __amd64 */ ucontext_32ton(&uc32, &uc); /* * libc stashed thrptr into unused kernel %sp. * See setup_context() in libc. */ thrptr = (uint32_t)uc32.uc_mcontext.gregs[ESP]; #endif } #endif /* _SYSCALL32_IMPL */ (void) save_syscall_args(); /* save args for tracing first */ mutex_enter(&curproc->p_lock); pool_barrier_enter(); mutex_exit(&curproc->p_lock); lwp = lwp_create(lwp_rtt, NULL, NULL, curproc, TS_STOPPED, curthread->t_pri, &sigmask, curthread->t_cid, 0); mutex_enter(&curproc->p_lock); pool_barrier_exit(); mutex_exit(&curproc->p_lock); if (lwp == NULL) return (set_errno(EAGAIN)); lwp_load(lwp, uc.uc_mcontext.gregs, thrptr); t = lwptot(lwp); /* * Copy the new lwp's lwpid into the caller's specified buffer. */ if (new_lwp && copyout(&t->t_tid, new_lwp, sizeof (id_t))) { /* * caller's buffer is not writable, return * EFAULT, and terminate new lwp. */ mutex_enter(&p->p_lock); t->t_proc_flag |= TP_EXITLWP; t->t_sig_check = 1; t->t_sysnum = 0; t->t_proc_flag &= ~TP_HOLDLWP; lwp_create_done(t); mutex_exit(&p->p_lock); return (set_errno(EFAULT)); } /* * clone callers context, if any. must be invoked * while -not- holding p_lock. */ if (curthread->t_ctx) lwp_createctx(curthread, t); /* * copy current contract templates */ lwp_ctmpl_copy(lwp, ttolwp(curthread)); mutex_enter(&p->p_lock); /* * Copy the syscall arguments to the new lwp's arg area * for the benefit of debuggers. */ t->t_sysnum = SYS_lwp_create; lwp->lwp_ap = lwp->lwp_arg; lwp->lwp_arg[0] = (long)ucp; lwp->lwp_arg[1] = (long)flags; lwp->lwp_arg[2] = (long)new_lwp; lwp->lwp_argsaved = 1; if (!(flags & (LWP_DETACHED|LWP_DAEMON))) t->t_proc_flag |= TP_TWAIT; if (flags & LWP_DAEMON) { t->t_proc_flag |= TP_DAEMON; p->p_lwpdaemon++; } tid = (int)t->t_tid; /* for /proc debuggers */ /* * We now set the newly-created lwp running. * If it is being created as LWP_SUSPENDED, we leave its * TP_HOLDLWP flag set so it will stop in system call exit. */ if (!(flags & LWP_SUSPENDED)) t->t_proc_flag &= ~TP_HOLDLWP; lwp_create_done(t); mutex_exit(&p->p_lock); return (tid); }
/* * Perform pre-system-call processing, including stopping for tracing, * auditing, microstate-accounting, etc. * * This routine is called only if the t_pre_sys flag is set. Any condition * requiring pre-syscall handling must set the t_pre_sys flag. If the * condition is persistent, this routine will repost t_pre_sys. */ int pre_syscall(int arg0) { unsigned int code; kthread_t *t = curthread; proc_t *p = ttoproc(t); klwp_t *lwp = ttolwp(t); struct regs *rp = lwptoregs(lwp); int repost; t->t_pre_sys = repost = 0; /* clear pre-syscall processing flag */ ASSERT(t->t_schedflag & TS_DONT_SWAP); syscall_mstate(LMS_USER, LMS_SYSTEM); /* * The syscall arguments in the out registers should be pointed to * by lwp_ap. If the args need to be copied so that the outs can * be changed without losing the ability to get the args for /proc, * they can be saved by save_syscall_args(), and lwp_ap will be * restored by post_syscall(). */ ASSERT(lwp->lwp_ap == (long *)&rp->r_o0); /* * Make sure the thread is holding the latest credentials for the * process. The credentials in the process right now apply to this * thread for the entire system call. */ if (t->t_cred != p->p_cred) { cred_t *oldcred = t->t_cred; /* * DTrace accesses t_cred in probe context. t_cred must * always be either NULL, or point to a valid, allocated cred * structure. */ t->t_cred = crgetcred(); crfree(oldcred); } /* * Undo special arrangements to single-step the lwp * so that a debugger will see valid register contents. * Also so that the pc is valid for syncfpu(). * Also so that a syscall like exec() can be stepped. */ if (lwp->lwp_pcb.pcb_step != STEP_NONE) { (void) prundostep(); repost = 1; } /* * Check for indirect system call in case we stop for tracing. * Don't allow multiple indirection. */ code = t->t_sysnum; if (code == 0 && arg0 != 0) { /* indirect syscall */ code = arg0; t->t_sysnum = arg0; } /* * From the proc(4) manual page: * When entry to a system call is being traced, the traced process * stops after having begun the call to the system but before the * system call arguments have been fetched from the process. * If proc changes the args we must refetch them after starting. */ if (PTOU(p)->u_systrap) { if (prismember(&PTOU(p)->u_entrymask, code)) { /* * Recheck stop condition, now that lock is held. */ mutex_enter(&p->p_lock); if (PTOU(p)->u_systrap && prismember(&PTOU(p)->u_entrymask, code)) { stop(PR_SYSENTRY, code); /* * Must refetch args since they were * possibly modified by /proc. Indicate * that the valid copy is in the * registers. */ lwp->lwp_argsaved = 0; lwp->lwp_ap = (long *)&rp->r_o0; } mutex_exit(&p->p_lock); } repost = 1; } if (lwp->lwp_sysabort) { /* * lwp_sysabort may have been set via /proc while the process * was stopped on PR_SYSENTRY. If so, abort the system call. * Override any error from the copyin() of the arguments. */ lwp->lwp_sysabort = 0; (void) set_errno(EINTR); /* sets post-sys processing */ t->t_pre_sys = 1; /* repost anyway */ return (1); /* don't do system call, return EINTR */ } #ifdef C2_AUDIT if (audit_active) { /* begin auditing for this syscall */ int error; if (error = audit_start(T_SYSCALL, code, 0, lwp)) { t->t_pre_sys = 1; /* repost anyway */ lwp->lwp_error = 0; /* for old drivers */ return (error); } repost = 1; } #endif /* C2_AUDIT */ #ifndef NPROBE /* Kernel probe */ if (tnf_tracing_active) { TNF_PROBE_1(syscall_start, "syscall thread", /* CSTYLED */, tnf_sysnum, sysnum, t->t_sysnum); t->t_post_sys = 1; /* make sure post_syscall runs */ repost = 1; } #endif /* NPROBE */ #ifdef SYSCALLTRACE if (syscalltrace) { int i; long *ap; char *cp; char *sysname; struct sysent *callp; if (code >= NSYSCALL) callp = &nosys_ent; /* nosys has no args */ else callp = LWP_GETSYSENT(lwp) + code; (void) save_syscall_args(); mutex_enter(&systrace_lock); printf("%d: ", p->p_pid); if (code >= NSYSCALL) printf("0x%x", code); else { sysname = mod_getsysname(code); printf("%s[0x%x]", sysname == NULL ? "NULL" : sysname, code); } cp = "("; for (i = 0, ap = lwp->lwp_ap; i < callp->sy_narg; i++, ap++) { printf("%s%lx", cp, *ap); cp = ", "; } if (i) printf(")"); printf(" %s id=0x%p\n", PTOU(p)->u_comm, curthread); mutex_exit(&systrace_lock); } #endif /* SYSCALLTRACE */ /* * If there was a continuing reason for pre-syscall processing, * set the t_pre_sys flag for the next system call. */ if (repost) t->t_pre_sys = 1; lwp->lwp_error = 0; /* for old drivers */ lwp->lwp_badpriv = PRIV_NONE; /* for privilege tracing */ return (0); }
/* * Clear registers on exec(2). */ void setregs(uarg_t *args) { struct regs *rp; kthread_t *t = curthread; klwp_t *lwp = ttolwp(t); pcb_t *pcb = &lwp->lwp_pcb; greg_t sp; /* * Initialize user registers */ (void) save_syscall_args(); /* copy args from registers first */ rp = lwptoregs(lwp); sp = rp->r_sp; bzero(rp, sizeof (*rp)); rp->r_ss = UDS_SEL; rp->r_sp = sp; rp->r_pc = args->entry; rp->r_ps = PSL_USER; #if defined(__amd64) pcb->pcb_fs = pcb->pcb_gs = 0; pcb->pcb_fsbase = pcb->pcb_gsbase = 0; if (ttoproc(t)->p_model == DATAMODEL_NATIVE) { rp->r_cs = UCS_SEL; /* * Only allow 64-bit user code descriptor to be present. */ gdt_ucode_model(DATAMODEL_NATIVE); /* * Arrange that the virtualized %fs and %gs GDT descriptors * have a well-defined initial state (present, ring 3 * and of type data). */ pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc; /* * thrptr is either NULL or a value used by DTrace. * 64-bit processes use %fs as their "thread" register. */ if (args->thrptr) (void) lwp_setprivate(lwp, _LWP_FSBASE, args->thrptr); } else { rp->r_cs = U32CS_SEL; rp->r_ds = rp->r_es = UDS_SEL; /* * only allow 32-bit user code selector to be present. */ gdt_ucode_model(DATAMODEL_ILP32); pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_u32desc; /* * thrptr is either NULL or a value used by DTrace. * 32-bit processes use %gs as their "thread" register. */ if (args->thrptr) (void) lwp_setprivate(lwp, _LWP_GSBASE, args->thrptr); } pcb->pcb_ds = rp->r_ds; pcb->pcb_es = rp->r_es; pcb->pcb_rupdate = 1; #elif defined(__i386) rp->r_cs = UCS_SEL; rp->r_ds = rp->r_es = UDS_SEL; /* * Arrange that the virtualized %fs and %gs GDT descriptors * have a well-defined initial state (present, ring 3 * and of type data). */ pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc; /* * For %gs we need to reset LWP_GSBASE in pcb and the * per-cpu GDT descriptor. thrptr is either NULL * or a value used by DTrace. */ if (args->thrptr) (void) lwp_setprivate(lwp, _LWP_GSBASE, args->thrptr); #endif lwp->lwp_eosys = JUSTRETURN; t->t_post_sys = 1; /* * Here we initialize minimal fpu state. * The rest is done at the first floating * point instruction that a process executes. */ pcb->pcb_fpu.fpu_flags = 0; /* * Add the lwp context handlers that virtualize segment registers, * and/or system call stacks etc. */ lwp_installctx(lwp); }