Fix tracking of unknown syscalls for 'truss -c'.

This is done by changing get_syscall() to either lookup the known syscall
or add it into the list with the default handlers for printing.

This also simplifies some code to not have to check if the syscall variable
is set or NULL.

Reviewed by:	jhb
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D3792

usr.bin/truss/main.c

@@ -94,6 +94,7 @@ main(int ac, char **av)
 	trussinfo->strsize = 32;
 	trussinfo->curthread = NULL;
 	LIST_INIT(&trussinfo->proclist);
+	init_syscalls();
 	while ((c = getopt(ac, av, "p:o:facedDs:S")) != -1) {
 		switch (c) {
 		case 'p':	/* specified pid */

usr.bin/truss/setup.c

@@ -341,17 +341,9 @@ enter_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
 		fprintf(info->outfile, "-- UNKNOWN %s SYSCALL %d --\n",
 		    t->proc->abi->type, t->cs.number);
 
-	sc = get_syscall(t->cs.name);
-	if (sc) {
-		t->cs.nargs = sc->nargs;
-		assert(sc->nargs <= nitems(t->cs.s_args));
-	} else {
-#if DEBUG
-		fprintf(stderr, "unknown syscall %s -- setting "
-		    "args to %d\n", t->cs.name, t->cs.nargs);
-#endif
-		t->cs.nargs = narg;
-	}
+	sc = get_syscall(t->cs.name, narg);
+	t->cs.nargs = sc->nargs;
+	assert(sc->nargs <= nitems(t->cs.s_args));
 
 	t->cs.sc = sc;
 
@@ -372,7 +364,7 @@ enter_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
 			    t->cs.args[sc->args[i].offset] : t->cs.args[i],
 			    i < (t->cs.nargs - 1) ? "," : "");
 #endif
-			if (sc && !(sc->args[i].type & OUT)) {
+			if (!(sc->args[i].type & OUT)) {
 				t->cs.s_args[i] = print_arg(&sc->args[i],
 				    t->cs.args, 0, info);
 			}
@@ -407,31 +399,26 @@ exit_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
 	}
 
 	sc = t->cs.sc;
-	if (sc == NULL) {
-		for (i = 0; i < t->cs.nargs; i++)
-			asprintf(&t->cs.s_args[i], "0x%lx", t->cs.args[i]);
-	} else {
-		/*
-		 * Here, we only look for arguments that have OUT masked in --
-		 * otherwise, they were handled in enter_syscall().
-		 */
-		for (i = 0; i < sc->nargs; i++) {
-			char *temp;
+	/*
+	 * Here, we only look for arguments that have OUT masked in --
+	 * otherwise, they were handled in enter_syscall().
+	 */
+	for (i = 0; i < sc->nargs; i++) {
+		char *temp;
 
-			if (sc->args[i].type & OUT) {
-				/*
-				 * If an error occurred, then don't bother
-				 * getting the data; it may not be valid.
-				 */
-				if (errorp) {
-					asprintf(&temp, "0x%lx",
-					    t->cs.args[sc->args[i].offset]);
-				} else {
-					temp = print_arg(&sc->args[i],
-					    t->cs.args, retval, info);
-				}
-				t->cs.s_args[i] = temp;
+		if (sc->args[i].type & OUT) {
+			/*
+			 * If an error occurred, then don't bother
+			 * getting the data; it may not be valid.
+			 */
+			if (errorp) {
+				asprintf(&temp, "0x%lx",
+				    t->cs.args[sc->args[i].offset]);
+			} else {
+				temp = print_arg(&sc->args[i],
+				    t->cs.args, retval, info);
 			}
+			t->cs.s_args[i] = temp;
 		}
 	}
 

usr.bin/truss/syscall.h

@@ -55,6 +55,7 @@ struct syscall_args {
 };
 
 struct syscall {
+	STAILQ_ENTRY(syscall) entries;
 	const char *name;
 	u_int ret_type;	/* 0, 1, or 2 return values */
 	u_int nargs;	/* actual number of meaningful arguments */
@@ -65,7 +66,7 @@ struct syscall {
 	int nerror;	/* Number of calls that returned with error */
 };
 
-struct syscall *get_syscall(const char*);
+struct syscall *get_syscall(const char *, int nargs);
 char *print_arg(struct syscall_args *, unsigned long*, long *, struct trussinfo *);
 
 /*
@@ -108,6 +109,7 @@ struct linux_socketcall_args {
     char args_l_[PADL_(l_ulong)]; l_ulong args; char args_r_[PADR_(l_ulong)];
 };
 
+void init_syscalls(void);
 void print_syscall(struct trussinfo *, const char *, int, char **);
 void print_syscall_ret(struct trussinfo *, const char *, int, char **, int,
     long *, struct syscall *);

usr.bin/truss/syscalls.c

@@ -89,7 +89,7 @@ __FBSDID("$FreeBSD$");
 /*
  * This should probably be in its own file, sorted alphabetically.
  */
-static struct syscall syscalls[] = {
+static struct syscall decoded_syscalls[] = {
 	{ .name = "fcntl", .ret_type = 1, .nargs = 3,
 	  .args = { { Int, 0 }, { Fcntl, 1 }, { Fcntlflag, 2 } } },
 	{ .name = "rfork", .ret_type = 1, .nargs = 1,
@@ -370,6 +370,7 @@ static struct syscall syscalls[] = {
 	  .args = { { Ptr, 0 } } },
 	{ .name = 0 },
 };
+static STAILQ_HEAD(, syscall) syscalls;
 
 /* Xlat idea taken from strace */
 struct xlat {
@@ -659,24 +660,49 @@ xlookup_bits(struct xlat *xlat, int val)
 	return (str);
 }
 
+void
+init_syscalls(void)
+{
+	struct syscall *sc;
+
+	STAILQ_INIT(&syscalls);
+	for (sc = decoded_syscalls; sc->name != NULL; sc++)
+		STAILQ_INSERT_HEAD(&syscalls, sc, entries);
+}
 /*
  * If/when the list gets big, it might be desirable to do it
  * as a hash table or binary search.
  */
 struct syscall *
-get_syscall(const char *name)
+get_syscall(const char *name, int nargs)
 {
 	struct syscall *sc;
+	int i;
 
-	sc = syscalls;
 	if (name == NULL)
 		return (NULL);
-	while (sc->name) {
+	STAILQ_FOREACH(sc, &syscalls, entries)
 		if (strcmp(name, sc->name) == 0)
 			return (sc);
-		sc++;
+
+	/* It is unknown.  Add it into the list. */
+#if DEBUG
+	fprintf(stderr, "unknown syscall %s -- setting args to %d\n", name,
+	    nargs);
+#endif
+
+	sc = calloc(1, sizeof(struct syscall));
+	sc->name = strdup(name);
+	sc->ret_type = 1;
+	sc->nargs = nargs;
+	for (i = 0; i < nargs; i++) {
+		sc->args[i].offset = i;
+		/* Treat all unknown arguments as LongHex. */
+		sc->args[i].type = LongHex;
 	}
-	return (NULL);
+	STAILQ_INSERT_HEAD(&syscalls, sc, entries);
+
+	return (sc);
 }
 
 /*
@@ -1632,8 +1658,6 @@ print_syscall_ret(struct trussinfo *trussinfo, const char *name, int nargs,
 	struct timespec timediff;
 
 	if (trussinfo->flags & COUNTONLY) {
-		if (!sc)
-			return;
 		clock_gettime(CLOCK_REALTIME, &trussinfo->curthread->after);
 		timespecsubt(&trussinfo->curthread->after,
 		    &trussinfo->curthread->before, &timediff);
@@ -1650,7 +1674,7 @@ print_syscall_ret(struct trussinfo *trussinfo, const char *name, int nargs,
 		fprintf(trussinfo->outfile, " ERR#%ld '%s'\n", retval[0],
 		    strerror(retval[0]));
 #ifndef __LP64__
-	else if (sc != NULL && sc->ret_type == 2) {
+	else if (sc->ret_type == 2) {
 		off_t off;
 
 #if _BYTE_ORDER == _LITTLE_ENDIAN
@@ -1677,7 +1701,7 @@ print_summary(struct trussinfo *trussinfo)
 	fprintf(trussinfo->outfile, "%-20s%15s%8s%8s\n",
 	    "syscall", "seconds", "calls", "errors");
 	ncall = nerror = 0;
-	for (sc = syscalls; sc->name != NULL; sc++)
+	STAILQ_FOREACH(sc, &syscalls, entries)
 		if (sc->ncalls) {
 			fprintf(trussinfo->outfile, "%-20s%5jd.%09ld%8d%8d\n",
 			    sc->name, (intmax_t)sc->time.tv_sec,