2 * Copryight 1997 Sean Eric Fagan
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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/syscall.h>
47 #include <sys/ptrace.h>
49 #include <machine/reg.h>
50 #include <machine/psl.h>
69 static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
72 * This is what this particular file uses to keep track of a system call.
73 * It is probably not quite sufficient -- I can probably use the same
74 * structure for the various syscall personalities, and I also probably
75 * need to nest system calls (for signal handlers).
77 * 'struct syscall' describes the system call; it may be NULL, however,
78 * if we don't know about this particular system call yet.
80 static struct freebsd_syscall {
85 int nargs; /* number of arguments -- *not* number of words! */
86 char **s_args; /* the printable arguments */
89 /* Clear up and free parts of the fsc structure. */
97 for (i = 0; i < fsc.nargs; i++)
102 memset(&fsc, 0, sizeof(fsc));
106 * Called when a process has entered a system call. nargs is the
107 * number of words, not number of arguments (a necessary distinction
108 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c
109 * is ever changed these functions need to keep up.
113 i386_syscall_entry(struct trussinfo *trussinfo, int nargs) {
117 unsigned int parm_offset;
118 struct syscall *sc = NULL;
119 struct ptrace_io_desc iorequest;
120 cpid = trussinfo->curthread->tid;
124 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0)
126 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
129 parm_offset = regs.r_esp + sizeof(int);
132 * FreeBSD has two special kinds of system call redirctions --
133 * SYS_syscall, and SYS___syscall. The former is the old syscall()
134 * routine, basicly; the latter is for quad-aligned arguments.
136 syscall_num = regs.r_eax;
137 switch (syscall_num) {
139 syscall_num = ptrace(PT_READ_D, cpid, (caddr_t)parm_offset, 0);
140 parm_offset += sizeof(int);
143 syscall_num = ptrace(PT_READ_D, cpid, (caddr_t)parm_offset, 0);
144 parm_offset += sizeof(quad_t);
148 fsc.number = syscall_num;
150 (syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num];
152 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num);
155 if (fsc.name && (trussinfo->flags & FOLLOWFORKS)
156 && ((!strcmp(fsc.name, "fork")
157 || !strcmp(fsc.name, "rfork")
158 || !strcmp(fsc.name, "vfork"))))
160 trussinfo->curthread->in_fork = 1;
166 fsc.args = malloc((1+nargs) * sizeof(unsigned long));
167 iorequest.piod_op = PIOD_READ_D;
168 iorequest.piod_offs = (void *)parm_offset;
169 iorequest.piod_addr = fsc.args;
170 iorequest.piod_len = (1+nargs) * sizeof(unsigned long);
171 ptrace(PT_IO, cpid, (caddr_t)&iorequest, 0);
172 if (iorequest.piod_len == 0)
176 sc = get_syscall(fsc.name);
178 fsc.nargs = sc->nargs;
181 fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n",
187 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
188 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
192 * At this point, we set up the system call arguments.
193 * We ignore any OUT ones, however -- those are arguments that
194 * are set by the system call, and so are probably meaningless
195 * now. This doesn't currently support arguments that are
196 * passed in *and* out, however.
202 fprintf(stderr, "syscall %s(", fsc.name);
204 for (i = 0; i < fsc.nargs; i++) {
206 fprintf(stderr, "0x%x%s",
208 ? fsc.args[sc->args[i].offset]
210 i < (fsc.nargs - 1) ? "," : "");
212 if (sc && !(sc->args[i].type & OUT)) {
213 fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo);
217 fprintf(stderr, ")\n");
222 fprintf(trussinfo->outfile, "\n");
225 if (fsc.name != NULL &&
226 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) {
229 * This could be done in a more general
230 * manner but it still wouldn't be very pretty.
232 if (!strcmp(fsc.name, "execve")) {
233 if ((trussinfo->flags & EXECVEARGS) == 0)
236 fsc.s_args[1] = NULL;
238 if ((trussinfo->flags & EXECVEENVS) == 0)
241 fsc.s_args[2] = NULL;
251 * And when the system call is done, we handle it here.
252 * Currently, no attempt is made to ensure that the system calls
253 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
254 * the sytem call number instead of, say, an error status).
258 i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
266 if (fsc.name == NULL)
268 cpid = trussinfo->curthread->tid;
270 if (ptrace(PT_GETREGS, cpid, (caddr_t)®s, 0) < 0)
272 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
277 errorp = !!(regs.r_eflags & PSL_C);
280 * This code, while simpler than the initial versions I used, could
281 * stand some significant cleaning.
286 for (i = 0; i < fsc.nargs; i++)
287 asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]);
290 * Here, we only look for arguments that have OUT masked in --
291 * otherwise, they were handled in the syscall_entry function.
293 for (i = 0; i < sc->nargs; i++) {
295 if (sc->args[i].type & OUT) {
297 * If an error occurred, then don't bother getting the data;
298 * it may not be valid.
301 asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]);
303 temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo);
304 fsc.s_args[i] = temp;
310 * The pipe syscall returns its fds in two registers and has assembly glue
311 * to provide the libc API, so it cannot be handled like regular syscalls.
312 * The nargs check is so we don't have to do yet another strcmp on every
315 if (!errorp && fsc.nargs == 0 && fsc.name && strcmp(fsc.name, "pipe") == 0) {
317 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
318 asprintf(&fsc.s_args[0], "[%d,%d]", (int)retval, regs.r_edx);
322 if (fsc.name != NULL &&
323 (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit"))) {
324 trussinfo->curthread->in_syscall = 1;
328 * It would probably be a good idea to merge the error handling,
329 * but that complicates things considerably.
332 print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval);