2 * Copryight 1997 Sean Eric Fagan
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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13 * must display the following acknowledgement:
14 * This product includes software developed by Sean Eric Fagan
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33 static const char rcsid[] =
38 * FreeBSD/i386-specific system call handling. This is probably the most
39 * complex part of the entire truss program, although I've got lots of
40 * it handled relatively cleanly now. The system call names are generated
41 * automatically, thanks to /usr/src/sys/kern/syscalls.master. The
42 * names used for the various structures are confusing, I sadly admit.
45 #include <sys/types.h>
46 #include <sys/ioctl.h>
47 #include <sys/pioctl.h>
48 #include <sys/syscall.h>
50 #include <machine/reg.h>
51 #include <machine/psl.h>
71 static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
74 * This is what this particular file uses to keep track of a system call.
75 * It is probably not quite sufficient -- I can probably use the same
76 * structure for the various syscall personalities, and I also probably
77 * need to nest system calls (for signal handlers).
79 * 'struct syscall' describes the system call; it may be NULL, however,
80 * if we don't know about this particular system call yet.
82 static struct freebsd_syscall {
87 int nargs; /* number of arguments -- *not* number of words! */
88 char **s_args; /* the printable arguments */
91 /* Clear up and free parts of the fsc structure. */
99 for (i = 0; i < fsc.nargs; i++)
104 memset(&fsc, 0, sizeof(fsc));
108 * Called when a process has entered a system call. nargs is the
109 * number of words, not number of arguments (a necessary distinction
110 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c
111 * is ever changed these functions need to keep up.
115 i386_syscall_entry(struct trussinfo *trussinfo, int nargs) {
120 unsigned int parm_offset;
123 if (fd == -1 || trussinfo->pid != cpid) {
124 sprintf(buf, "/proc/%d/regs", trussinfo->pid);
125 fd = open(buf, O_RDWR);
127 fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n");
130 cpid = trussinfo->pid;
135 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) {
136 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
139 parm_offset = regs.r_esp + sizeof(int);
142 * FreeBSD has two special kinds of system call redirctions --
143 * SYS_syscall, and SYS___syscall. The former is the old syscall()
144 * routine, basicly; the latter is for quad-aligned arguments.
146 syscall_num = regs.r_eax;
147 switch (syscall_num) {
149 lseek(Procfd, parm_offset, SEEK_SET);
150 read(Procfd, &syscall_num, sizeof(int));
151 parm_offset += sizeof(int);
154 lseek(Procfd, parm_offset, SEEK_SET);
155 read(Procfd, &syscall_num, sizeof(int));
156 parm_offset += sizeof(quad_t);
160 fsc.number = syscall_num;
162 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num];
164 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num);
167 if (fsc.name && (trussinfo->flags & FOLLOWFORKS)
168 && ((!strcmp(fsc.name, "fork")
169 || !strcmp(fsc.name, "rfork")
170 || !strcmp(fsc.name, "vfork"))))
172 trussinfo->in_fork = 1;
178 fsc.args = malloc((1+nargs) * sizeof(unsigned long));
179 lseek(Procfd, parm_offset, SEEK_SET);
180 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1)
184 sc = get_syscall(fsc.name);
186 fsc.nargs = sc->nargs;
189 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n",
195 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
196 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
200 * At this point, we set up the system call arguments.
201 * We ignore any OUT ones, however -- those are arguments that
202 * are set by the system call, and so are probably meaningless
203 * now. This doesn't currently support arguments that are
204 * passed in *and* out, however.
210 fprintf(stderr, "syscall %s(", fsc.name);
212 for (i = 0; i < fsc.nargs; i++) {
214 fprintf(stderr, "0x%x%s",
216 ? fsc.args[sc->args[i].offset]
218 i < (fsc.nargs - 1) ? "," : "");
220 if (sc && !(sc->args[i].type & OUT)) {
221 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args, 0, trussinfo);
225 fprintf(stderr, ")\n");
230 fprintf(trussinfo->outfile, "\n");
234 * Some system calls should be printed out before they are done --
235 * execve() and exit(), for example, never return. Possibly change
236 * this to work for any system call that doesn't have an OUT
240 if (fsc.name != NULL &&
241 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) {
244 * This could be done in a more general
245 * manner but it still wouldn't be very pretty.
247 if (!strcmp(fsc.name, "execve")) {
248 if ((trussinfo->flags & EXECVEARGS) == 0)
251 fsc.s_args[1] = NULL;
253 if ((trussinfo->flags & EXECVEENVS) == 0)
256 fsc.s_args[2] = NULL;
260 print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args);
261 fprintf(trussinfo->outfile, "\n");
268 * And when the system call is done, we handle it here.
269 * Currently, no attempt is made to ensure that the system calls
270 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
271 * the sytem call number instead of, say, an error status).
275 i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
284 if (fd == -1 || trussinfo->pid != cpid) {
285 sprintf(buf, "/proc/%d/regs", trussinfo->pid);
286 fd = open(buf, O_RDONLY);
288 fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n");
291 cpid = trussinfo->pid;
295 if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) {
296 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
300 errorp = !!(regs.r_eflags & PSL_C);
303 * This code, while simpler than the initial versions I used, could
304 * stand some significant cleaning.
309 for (i = 0; i < fsc.nargs; i++)
310 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]);
313 * Here, we only look for arguments that have OUT masked in --
314 * otherwise, they were handled in the syscall_entry function.
316 for (i = 0; i < sc->nargs; i++) {
318 if (sc->args[i].type & OUT) {
320 * If an error occurred, then don't bother getting the data;
321 * it may not be valid.
324 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]);
326 temp = print_arg(Procfd, &sc->args[i], fsc.args, retval, trussinfo);
327 fsc.s_args[i] = temp;
333 * The pipe syscall returns its fds in two registers and has assembly glue
334 * to provide the libc API, so it cannot be handled like regular syscalls.
335 * The nargs check is so we don't have to do yet another strcmp on every
338 if (!errorp && fsc.nargs == 0 && fsc.name && strcmp(fsc.name, "pipe") == 0) {
340 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
341 asprintf(&fsc.s_args[0], "[%d,%d]", (int)retval, regs.r_edx);
346 * It would probably be a good idea to merge the error handling,
347 * but that complicates things considerably.
350 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval);