/* * 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/386-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 <sys/types.h> #include <sys/ioctl.h> #include <sys/pioctl.h> #include <sys/syscall.h> #include <machine/reg.h> #include <machine/psl.h> #include <errno.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "syscall.h" static int fd = -1; static int cpid = -1; extern int Procfd; extern FILE *outfile; #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; 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() { 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 i386/i386/trap.c * is ever changed these functions need to keep up. */ void i386_syscall_entry(int pid, int nargs) { char buf[32]; struct reg regs = { 0 }; int syscall; int i; unsigned int parm_offset; struct syscall *sc; if (fd == -1 || pid != cpid) { sprintf(buf, "/proc/%d/regs", pid); fd = open(buf, O_RDWR); if (fd == -1) { fprintf(outfile, "-- CANNOT READ REGISTERS --\n"); return; } cpid = pid; } clear_fsc(); lseek(fd, 0L, 0); i = read(fd, ®s, sizeof(regs)); parm_offset = regs.r_esp + sizeof(int); /* * 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. */ syscall = regs.r_eax; switch (syscall) { case SYS_syscall: lseek(Procfd, parm_offset, SEEK_SET); read(Procfd, &syscall, sizeof(int)); parm_offset += sizeof(int); break; case SYS___syscall: lseek(Procfd, parm_offset, SEEK_SET); read(Procfd, &syscall, sizeof(int)); parm_offset += sizeof(quad_t); break; } fsc.number = syscall; fsc.name = (syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall]; if (!fsc.name) { fprintf(outfile, "-- UNKNOWN SYSCALL %d --\n", syscall); } if (nargs == 0) return; fsc.args = malloc((1+nargs) * sizeof(unsigned long)); lseek(Procfd, parm_offset, SEEK_SET); if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) return; sc = get_syscall(fsc.name); if (sc) { fsc.nargs = sc->nargs; } else { #if DEBUG fprintf(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%x%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(Procfd, &sc->args[i], fsc.args); } } #if DEBUG fprintf(stderr, ")\n"); #endif } #if DEBUG fprintf(outfile, "\n"); #endif /* * Some system calls should be printed out before they are done -- * execve() and exit(), for example, never return. Possibly change * this to work for any system call that doesn't have an OUT * parameter? */ if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) { print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args); } 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). */ void i386_syscall_exit(int pid, int syscall) { char buf[32]; struct reg regs; int retval; int i; int errorp; struct syscall *sc; if (fd == -1 || pid != cpid) { sprintf(buf, "/proc/%d/regs", pid); fd = open(buf, O_RDONLY); if (fd == -1) { fprintf(outfile, "-- CANNOT READ REGISTERS --\n"); return; } cpid = pid; } lseek(fd, 0L, 0); if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) return; retval = regs.r_eax; errorp = !!(regs.r_eflags & 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++) { fsc.s_args[i] = malloc(12); sprintf(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) { temp = malloc(12); sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]); } else { temp = print_arg(Procfd, &sc->args[i], fsc.args); } fsc.s_args[i] = temp; } } } /* * It would probably be a good idea to merge the error handling, * but that complicates things considerably. */ print_syscall_ret(outfile, fsc.name, fsc.nargs, fsc.s_args, errorp, retval); clear_fsc(); return; }