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
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
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11 * documentation and/or other materials provided with the distribution.
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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/386-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.
52 #include <sys/ioctl.h>
53 #include <sys/pioctl.h>
54 #include <machine/reg.h>
55 #include <machine/psl.h>
56 #include <sys/syscall.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 static struct freebsd_syscall {
83 int nargs; /* number of arguments -- *not* number of words! */
84 char **s_args; /* the printable arguments */
87 /* Clear up and free parts of the fsc structure. */
95 for (i = 0; i < fsc.nargs; i++)
100 memset(&fsc, 0, sizeof(fsc));
104 * Called when a process has entered a system call. nargs is the
105 * number of words, not number of arguments (a necessary distinction
106 * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c
107 * is ever changed these functions need to keep up.
111 i386_syscall_entry(int pid, int nargs) {
113 struct reg regs = { 0 };
116 unsigned int parm_offset;
119 if (fd == -1 || pid != cpid) {
120 sprintf(buf, "/proc/%d/regs", pid);
121 fd = open(buf, O_RDWR);
123 fprintf(outfile, "-- CANNOT READ REGISTERS --\n");
131 i = read(fd, ®s, sizeof(regs));
132 parm_offset = regs.r_esp + sizeof(int);
135 * FreeBSD has two special kinds of system call redirctions --
136 * SYS_syscall, and SYS___syscall. The former is the old syscall()
137 * routine, basicly; the latter is for quad-aligned arguments.
139 syscall = regs.r_eax;
142 lseek(Procfd, parm_offset, SEEK_SET);
143 read(Procfd, &syscall, sizeof(int));
144 parm_offset += sizeof(int);
147 lseek(Procfd, parm_offset, SEEK_SET);
148 read(Procfd, &syscall, sizeof(int));
149 parm_offset += sizeof(quad_t);
153 fsc.number = syscall;
155 (syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall];
157 fprintf(outfile, "-- UNKNOWN SYSCALL %d --\n", syscall);
163 fsc.args = malloc((1+nargs) * sizeof(unsigned long));
164 lseek(Procfd, parm_offset, SEEK_SET);
165 if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1)
168 sc = get_syscall(fsc.name);
170 fsc.nargs = sc->nargs;
173 fprintf(outfile, "unknown syscall %s -- setting args to %d\n",
179 fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
180 memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
184 * At this point, we set up the system call arguments.
185 * We ignore any OUT ones, however -- those are arguments that
186 * are set by the system call, and so are probably meaningless
187 * now. This doesn't currently support arguments that are
188 * passed in *and* out, however.
194 fprintf(stderr, "syscall %s(", fsc.name);
196 for (i = 0; i < fsc.nargs; i++) {
198 fprintf(stderr, "0x%x%s",
200 ? fsc.args[sc->args[i].offset]
202 i < (fsc.nargs -1) ? "," : "");
204 if (sc && !(sc->args[i].type & OUT)) {
205 fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args);
209 fprintf(stderr, ")\n");
214 fprintf(outfile, "\n");
218 * Some system calls should be printed out before they are done --
219 * execve() and exit(), for example, never return. Possibly change
220 * this to work for any system call that doesn't have an OUT
224 if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) {
225 print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args);
232 * And when the system call is done, we handle it here.
233 * Currently, no attempt is made to ensure that the system calls
234 * match -- this needs to be fixed (and is, in fact, why S_SCX includes
235 * the sytem call number instead of, say, an error status).
239 i386_syscall_exit(int pid, int syscall) {
247 if (fd == -1 || pid != cpid) {
248 sprintf(buf, "/proc/%d/regs", pid);
249 fd = open(buf, O_RDONLY);
251 fprintf(outfile, "-- CANNOT READ REGISTERS --\n");
258 if (read(fd, ®s, sizeof(regs)) != sizeof(regs))
261 errorp = !!(regs.r_eflags & PSL_C);
264 * This code, while simpler than the initial versions I used, could
265 * stand some significant cleaning.
270 for (i = 0; i < fsc.nargs; i++) {
271 fsc.s_args[i] = malloc(12);
272 sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]);
276 * Here, we only look for arguments that have OUT masked in --
277 * otherwise, they were handled in the syscall_entry function.
279 for (i = 0; i < sc->nargs; i++) {
281 if (sc->args[i].type & OUT) {
283 * If an error occurred, than don't bothe getting the data;
284 * it may not be valid.
288 sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]);
290 temp = print_arg(Procfd, &sc->args[i], fsc.args);
292 fsc.s_args[i] = temp;
298 * It would probably be a good idea to merge the error handling,
299 * but that complicates things considerably.
302 print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args);
304 fprintf(outfile, "errno %d '%s'\n", retval, strerror(retval));
306 fprintf(outfile, "returns %d (0x%x)\n", retval, retval);