2 * Copyright 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
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 * must display the following acknowledgement:
14 * This product includes software developed by Sean Eric Fagan
15 * 4. Neither the name of the author may be used to endorse or promote
16 * products derived from this software without specific prior written
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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/ptrace.h>
47 #include <sys/syscall.h>
49 #include <machine/reg.h>
50 #include <machine/psl.h>
67 static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
70 * This is what this particular file uses to keep track of a system call.
71 * It is probably not quite sufficient -- I can probably use the same
72 * structure for the various syscall personalities, and I also probably
73 * need to nest system calls (for signal handlers).
75 * 'struct syscall' describes the system call; it may be NULL, however,
76 * if we don't know about this particular system call yet.
78 struct freebsd_syscall {
83 int nargs; /* number of arguments -- *not* number of words! */
84 char **s_args; /* the printable arguments */
87 static struct freebsd_syscall *
91 return (malloc(sizeof(struct freebsd_syscall)));
94 /* Clear up and free parts of the fsc structure. */
96 free_fsc(struct freebsd_syscall *fsc)
102 for (i = 0; i < fsc->nargs; i++)
103 free(fsc->s_args[i]);
110 * Called when a process has entered a system call. nargs is the
111 * number of words, not number of arguments (a necessary distinction
112 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c
113 * is ever changed these functions need to keep up.
117 i386_syscall_entry(struct trussinfo *trussinfo, int nargs)
119 struct ptrace_io_desc iorequest;
121 struct freebsd_syscall *fsc;
124 unsigned int parm_offset;
127 tid = trussinfo->curthread->tid;
129 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) {
130 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
133 parm_offset = regs.r_esp + sizeof(int);
136 * FreeBSD has two special kinds of system call redirctions --
137 * SYS_syscall, and SYS___syscall. The former is the old syscall()
138 * routine, basically; the latter is for quad-aligned arguments.
140 syscall_num = regs.r_eax;
141 switch (syscall_num) {
143 syscall_num = ptrace(PT_READ_D, tid, (caddr_t)parm_offset, 0);
144 parm_offset += sizeof(int);
147 syscall_num = ptrace(PT_READ_D, tid, (caddr_t)parm_offset, 0);
148 parm_offset += sizeof(quad_t);
155 fsc->number = syscall_num;
156 fsc->name = (syscall_num < 0 || syscall_num >= nsyscalls) ?
157 NULL : syscallnames[syscall_num];
159 fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n",
163 if (fsc->name && (trussinfo->flags & FOLLOWFORKS) &&
164 (strcmp(fsc->name, "fork") == 0 ||
165 strcmp(fsc->name, "rfork") == 0 ||
166 strcmp(fsc->name, "vfork") == 0))
167 trussinfo->curthread->in_fork = 1;
172 fsc->args = malloc((1 + nargs) * sizeof(unsigned long));
173 iorequest.piod_op = PIOD_READ_D;
174 iorequest.piod_offs = (void *)parm_offset;
175 iorequest.piod_addr = fsc->args;
176 iorequest.piod_len = (1 + nargs) * sizeof(unsigned long);
177 ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
178 if (iorequest.piod_len == 0)
183 sc = get_syscall(fsc->name);
185 fsc->nargs = sc->nargs;
188 fprintf(trussinfo->outfile, "unknown syscall %s -- setting "
189 "args to %d\n", fsc->name, nargs);
194 fsc->s_args = calloc(1, (1 + fsc->nargs) * sizeof(char *));
198 * At this point, we set up the system call arguments.
199 * We ignore any OUT ones, however -- those are arguments that
200 * are set by the system call, and so are probably meaningless
201 * now. This doesn't currently support arguments that are
202 * passed in *and* out, however.
207 fprintf(stderr, "syscall %s(", fsc->name);
209 for (i = 0; i < fsc->nargs; i++) {
211 fprintf(stderr, "0x%x%s", sc ?
212 fsc->args[sc->args[i].offset] : fsc->args[i],
213 i < (fsc->nargs - 1) ? "," : "");
215 if (sc && !(sc->args[i].type & OUT)) {
216 fsc->s_args[i] = print_arg(&sc->args[i],
217 fsc->args, 0, trussinfo);
221 fprintf(stderr, ")\n");
226 fprintf(trussinfo->outfile, "\n");
229 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 ||
230 strcmp(fsc->name, "exit") == 0)) {
233 * This could be done in a more general
234 * manner but it still wouldn't be very pretty.
236 if (strcmp(fsc->name, "execve") == 0) {
237 if ((trussinfo->flags & EXECVEARGS) == 0) {
238 if (fsc->s_args[1]) {
239 free(fsc->s_args[1]);
240 fsc->s_args[1] = NULL;
243 if ((trussinfo->flags & EXECVEENVS) == 0) {
244 if (fsc->s_args[2]) {
245 free(fsc->s_args[2]);
246 fsc->s_args[2] = NULL;
251 trussinfo->curthread->fsc = fsc;
255 * And when the system call is done, we handle it here.
256 * Currently, no attempt is made to ensure that the system calls
257 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
258 * the system call number instead of, say, an error status).
262 i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
265 struct freebsd_syscall *fsc;
271 if (trussinfo->curthread->fsc == NULL)
274 tid = trussinfo->curthread->tid;
276 if (ptrace(PT_GETREGS, tid, (caddr_t)®s, 0) < 0) {
277 fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
282 errorp = !!(regs.r_eflags & PSL_C);
285 * This code, while simpler than the initial versions I used, could
286 * stand some significant cleaning.
289 fsc = trussinfo->curthread->fsc;
292 for (i = 0; i < fsc->nargs; i++)
293 asprintf(&fsc->s_args[i], "0x%lx", fsc->args[i]);
296 * Here, we only look for arguments that have OUT masked in --
297 * otherwise, they were handled in the syscall_entry function.
299 for (i = 0; i < sc->nargs; i++) {
301 if (sc->args[i].type & OUT) {
303 * If an error occurred, then don't bother
304 * getting the data; it may not be valid.
307 asprintf(&temp, "0x%lx",
308 fsc->args[sc->args[i].offset]);
310 temp = print_arg(&sc->args[i],
311 fsc->args, retval, trussinfo);
313 fsc->s_args[i] = temp;
318 if (fsc->name != NULL && (strcmp(fsc->name, "execve") == 0 ||
319 strcmp(fsc->name, "exit") == 0))
320 trussinfo->curthread->in_syscall = 1;
323 * It would probably be a good idea to merge the error handling,
324 * but that complicates things considerably.
327 print_syscall_ret(trussinfo, fsc->name, fsc->nargs, fsc->s_args, errorp,