/* * Copryight 1997 Sean Eric Fagan * * 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 Sean Eric Fagan * 4. Neither the name of the author may be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. */ #ifndef lint static const char rcsid[] = "$FreeBSD$"; #endif /* not lint */ /* * FreeBSD/amd64-specific system call handling. This is probably the most * complex part of the entire truss program, although I've got lots of * it handled relatively cleanly now. The system call names are generated * automatically, thanks to /usr/src/sys/kern/syscalls.master. The * names used for the various structures are confusing, I sadly admit. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "truss.h" #include "syscall.h" #include "extern.h" static int cpid = -1; #include "syscalls.h" static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); /* * This is what this particular file uses to keep track of a system call. * It is probably not quite sufficient -- I can probably use the same * structure for the various syscall personalities, and I also probably * need to nest system calls (for signal handlers). * * 'struct syscall' describes the system call; it may be NULL, however, * if we don't know about this particular system call yet. */ static struct freebsd_syscall { struct syscall *sc; const char *name; int number; unsigned long *args; int nargs; /* number of arguments -- *not* number of words! */ char **s_args; /* the printable arguments */ } fsc; /* Clear up and free parts of the fsc structure. */ static __inline void clear_fsc(void) { if (fsc.args) { free(fsc.args); } if (fsc.s_args) { int i; for (i = 0; i < fsc.nargs; i++) if (fsc.s_args[i]) free(fsc.s_args[i]); free(fsc.s_args); } memset(&fsc, 0, sizeof(fsc)); } /* * Called when a process has entered a system call. nargs is the * number of words, not number of arguments (a necessary distinction * in some cases). Note that if the STOPEVENT() code in amd64/amd64/trap.c * is ever changed these functions need to keep up. */ void amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) { struct reg regs; int syscall_num; int i, reg; struct syscall *sc; cpid = trussinfo->curthread->tid; clear_fsc(); if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) { fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); return; } /* * FreeBSD has two special kinds of system call redirctions -- * SYS_syscall, and SYS___syscall. The former is the old syscall() * routine, basicly; the latter is for quad-aligned arguments. */ reg = 0; syscall_num = regs.r_rax; switch (syscall_num) { case SYS_syscall: case SYS___syscall: syscall_num = regs.r_rdi; reg++; break; } fsc.number = syscall_num; fsc.name = (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num]; if (!fsc.name) { fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num); } if (fsc.name && (trussinfo->flags & FOLLOWFORKS) && ((!strcmp(fsc.name, "fork") || !strcmp(fsc.name, "rfork") || !strcmp(fsc.name, "vfork")))) { trussinfo->curthread->in_fork = 1; } if (nargs == 0) return; fsc.args = malloc((1+nargs) * sizeof(unsigned long)); for (i = 0; i < nargs && reg < 6; i++, reg++) { switch (reg) { case 0: fsc.args[i] = regs.r_rdi; break; case 1: fsc.args[i] = regs.r_rsi; break; case 2: fsc.args[i] = regs.r_rdx; break; case 3: fsc.args[i] = regs.r_rcx; break; case 4: fsc.args[i] = regs.r_r8; break; case 5: fsc.args[i] = regs.r_r9; break; } } if (nargs > i) { struct ptrace_io_desc iorequest; iorequest.piod_op = PIOD_READ_D; iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t)); iorequest.piod_addr = &fsc.args[i]; iorequest.piod_len = (nargs - i) * sizeof(register_t); ptrace(PT_IO, cpid, (caddr_t)&iorequest, 0); if (iorequest.piod_len == 0) return; } sc = get_syscall(fsc.name); if (sc) { fsc.nargs = sc->nargs; } else { #if DEBUG fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n", fsc.name, nargs); #endif fsc.nargs = nargs; } fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); fsc.sc = sc; /* * At this point, we set up the system call arguments. * We ignore any OUT ones, however -- those are arguments that * are set by the system call, and so are probably meaningless * now. This doesn't currently support arguments that are * passed in *and* out, however. */ if (fsc.name) { #if DEBUG fprintf(stderr, "syscall %s(", fsc.name); #endif for (i = 0; i < fsc.nargs; i++) { #if DEBUG fprintf(stderr, "0x%lx%s", sc ? fsc.args[sc->args[i].offset] : fsc.args[i], i < (fsc.nargs - 1) ? "," : ""); #endif if (sc && !(sc->args[i].type & OUT)) { fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo); } } #if DEBUG fprintf(stderr, ")\n"); #endif } #if DEBUG fprintf(trussinfo->outfile, "\n"); #endif if (fsc.name != NULL && (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { /* XXX * This could be done in a more general * manner but it still wouldn't be very pretty. */ if (!strcmp(fsc.name, "execve")) { if ((trussinfo->flags & EXECVEARGS) == 0) if (fsc.s_args[1]) { free(fsc.s_args[1]); fsc.s_args[1] = NULL; } if ((trussinfo->flags & EXECVEENVS) == 0) if (fsc.s_args[2]) { free(fsc.s_args[2]); fsc.s_args[2] = NULL; } } } return; } /* * And when the system call is done, we handle it here. * Currently, no attempt is made to ensure that the system calls * match -- this needs to be fixed (and is, in fact, why S_SCX includes * the sytem call number instead of, say, an error status). */ long amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused) { struct reg regs; long retval; int i; int errorp; struct syscall *sc; if (fsc.name == NULL) return (-1); cpid = trussinfo->curthread->tid; if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0) { fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n"); return (-1); } retval = regs.r_rax; errorp = !!(regs.r_rflags & PSL_C); /* * This code, while simpler than the initial versions I used, could * stand some significant cleaning. */ sc = fsc.sc; if (!sc) { for (i = 0; i < fsc.nargs; i++) asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]); } else { /* * Here, we only look for arguments that have OUT masked in -- * otherwise, they were handled in the syscall_entry function. */ for (i = 0; i < sc->nargs; i++) { char *temp; if (sc->args[i].type & OUT) { /* * If an error occurred, than don't bothe getting the data; * it may not be valid. */ if (errorp) asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]); else temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo); fsc.s_args[i] = temp; } } } if (fsc.name != NULL && (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) { trussinfo->curthread->in_syscall = 1; } /* * It would probably be a good idea to merge the error handling, * but that complicates things considerably. */ print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval, fsc.sc); clear_fsc(); return (retval); }