diff options
Diffstat (limited to 'sys/kern/subr_syscall.c')
| -rw-r--r-- | sys/kern/subr_syscall.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/sys/kern/subr_syscall.c b/sys/kern/subr_syscall.c new file mode 100644 index 0000000..fe5cd0e --- /dev/null +++ b/sys/kern/subr_syscall.c @@ -0,0 +1,237 @@ +/*- + * Copyright (C) 1994, David Greenman + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org> + * + * This code is derived from software contributed to Berkeley by + * the University of Utah, and William Jolitz. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 + */ + +#include "opt_capsicum.h" +#include "opt_ktrace.h" +#include "opt_kdtrace.h" + +__FBSDID("$FreeBSD$"); + +#include <sys/capability.h> +#include <sys/ktr.h> +#ifdef KTRACE +#include <sys/uio.h> +#include <sys/ktrace.h> +#endif +#include <security/audit/audit.h> + +static inline int +syscallenter(struct thread *td, struct syscall_args *sa) +{ + struct proc *p; + int error, traced; + + PCPU_INC(cnt.v_syscall); + p = td->td_proc; + + td->td_pticks = 0; + if (td->td_ucred != p->p_ucred) + cred_update_thread(td); + if (p->p_flag & P_TRACED) { + traced = 1; + PROC_LOCK(p); + td->td_dbgflags &= ~TDB_USERWR; + td->td_dbgflags |= TDB_SCE; + PROC_UNLOCK(p); + } else + traced = 0; + error = (p->p_sysent->sv_fetch_syscall_args)(td, sa); +#ifdef KTRACE + if (KTRPOINT(td, KTR_SYSCALL)) + ktrsyscall(sa->code, sa->narg, sa->args); +#endif + + CTR6(KTR_SYSC, +"syscall: td=%p pid %d %s (%#lx, %#lx, %#lx)", + td, td->td_proc->p_pid, syscallname(p, sa->code), + sa->args[0], sa->args[1], sa->args[2]); + + if (error == 0) { + STOPEVENT(p, S_SCE, sa->narg); + if (p->p_flag & P_TRACED && p->p_stops & S_PT_SCE) { + PROC_LOCK(p); + ptracestop((td), SIGTRAP); + PROC_UNLOCK(p); + } + if (td->td_dbgflags & TDB_USERWR) { + /* + * Reread syscall number and arguments if + * debugger modified registers or memory. + */ + error = (p->p_sysent->sv_fetch_syscall_args)(td, sa); +#ifdef KTRACE + if (KTRPOINT(td, KTR_SYSCALL)) + ktrsyscall(sa->code, sa->narg, sa->args); +#endif + if (error != 0) + goto retval; + } + +#ifdef CAPABILITY_MODE + /* + * In capability mode, we only allow access to system calls + * flagged with SYF_CAPENABLED. + */ + if (IN_CAPABILITY_MODE(td) && + !(sa->callp->sy_flags & SYF_CAPENABLED)) { + error = ECAPMODE; + goto retval; + } +#endif + + error = syscall_thread_enter(td, sa->callp); + if (error != 0) + goto retval; + +#ifdef KDTRACE_HOOKS + /* + * If the systrace module has registered it's probe + * callback and if there is a probe active for the + * syscall 'entry', process the probe. + */ + if (systrace_probe_func != NULL && sa->callp->sy_entry != 0) + (*systrace_probe_func)(sa->callp->sy_entry, sa->code, + sa->callp, sa->args, 0); +#endif + + AUDIT_SYSCALL_ENTER(sa->code, td); + error = (sa->callp->sy_call)(td, sa->args); + AUDIT_SYSCALL_EXIT(error, td); + + /* Save the latest error return value. */ + if ((td->td_pflags & TDP_NERRNO) == 0) + td->td_errno = error; + +#ifdef KDTRACE_HOOKS + /* + * If the systrace module has registered it's probe + * callback and if there is a probe active for the + * syscall 'return', process the probe. + */ + if (systrace_probe_func != NULL && sa->callp->sy_return != 0) + (*systrace_probe_func)(sa->callp->sy_return, sa->code, + sa->callp, NULL, (error) ? -1 : td->td_retval[0]); +#endif + syscall_thread_exit(td, sa->callp); + CTR4(KTR_SYSC, "syscall: p=%p error=%d return %#lx %#lx", + p, error, td->td_retval[0], td->td_retval[1]); + } + retval: + if (traced) { + PROC_LOCK(p); + td->td_dbgflags &= ~TDB_SCE; + PROC_UNLOCK(p); + } + (p->p_sysent->sv_set_syscall_retval)(td, error); + return (error); +} + +static inline void +syscallret(struct thread *td, int error, struct syscall_args *sa __unused) +{ + struct proc *p, *p2; + int traced; + + p = td->td_proc; + + /* + * Handle reschedule and other end-of-syscall issues + */ + userret(td, td->td_frame); + + CTR4(KTR_SYSC, "syscall %s exit thread %p pid %d proc %s", + syscallname(p, sa->code), td, td->td_proc->p_pid, td->td_name); + +#ifdef KTRACE + if (KTRPOINT(td, KTR_SYSRET)) { + ktrsysret(sa->code, (td->td_pflags & TDP_NERRNO) == 0 ? + error : td->td_errno, td->td_retval[0]); + } +#endif + td->td_pflags &= ~TDP_NERRNO; + + if (p->p_flag & P_TRACED) { + traced = 1; + PROC_LOCK(p); + td->td_dbgflags |= TDB_SCX; + PROC_UNLOCK(p); + } else + traced = 0; + /* + * This works because errno is findable through the + * register set. If we ever support an emulation where this + * is not the case, this code will need to be revisited. + */ + STOPEVENT(p, S_SCX, sa->code); + if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) { + PROC_LOCK(p); + /* + * If tracing the execed process, trap to the debugger + * so that breakpoints can be set before the program + * executes. If debugger requested tracing of syscall + * returns, do it now too. + */ + if (traced && + ((td->td_dbgflags & (TDB_FORK | TDB_EXEC)) != 0 || + (p->p_stops & S_PT_SCX) != 0)) + ptracestop(td, SIGTRAP); + td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK); + PROC_UNLOCK(p); + } + + if (td->td_pflags & TDP_RFPPWAIT) { + /* + * Preserve synchronization semantics of vfork. If + * waiting for child to exec or exit, fork set + * P_PPWAIT on child, and there we sleep on our proc + * (in case of exit). + * + * Do it after the ptracestop() above is finished, to + * not block our debugger until child execs or exits + * to finish vfork wait. + */ + td->td_pflags &= ~TDP_RFPPWAIT; + p2 = td->td_rfppwait_p; + PROC_LOCK(p2); + while (p2->p_flag & P_PPWAIT) + cv_wait(&p2->p_pwait, &p2->p_mtx); + PROC_UNLOCK(p2); + } +} |
