btrace(8): fix probe builtin in BEGIN/END.

Resolves segfaults when using probe within BEGIN or END.

ok mpi@

diff --git a/regress/usr.sbin/btrace/beginend.bt b/regress/usr.sbin/btrace/beginend.bt
index a246996..fb603b1 100644 (file)
--- a/regress/usr.sbin/btrace/beginend.bt
+++ b/regress/usr.sbin/btrace/beginend.bt
@@ -3,11 +3,11 @@
 BEGIN
 {
 
-       printf("Hello from BEGIN\n");
+       printf("Hello from %s\n", probe);
 }
 
 END
 {
        // Comment inside of a block
-       printf("Bye from END\n");
+       printf("Bye from %s\n", probe);
 }

diff --git a/usr.sbin/btrace/btrace.c b/usr.sbin/btrace/btrace.c
index 45e485b..f570911 100644 (file)
--- a/usr.sbin/btrace/btrace.c
+++ b/usr.sbin/btrace/btrace.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: btrace.c,v 1.74 2023/08/16 13:07:11 dv Exp $ */
+/*     $OpenBSD: btrace.c,v 1.75 2023/09/02 15:16:12 dv Exp $ */
 
 /*
  * Copyright (c) 2019 - 2021 Martin Pieuchot <mpi@openbsd.org>
@@ -117,6 +117,8 @@ size_t                       dt_ndtpi;      /* # of elements in the array */
 struct dtioc_arg_info  **dt_args;      /* array of probe arguments */
 
 struct dt_evt           bt_devt;       /* fake event for BEGIN/END */
+#define EVENT_BEGIN     0
+#define EVENT_END       (unsigned int)(-1)
 uint64_t                bt_filtered;   /* # of events filtered out */
 
 struct syms            *kelf, *uelf;
@@ -543,7 +545,7 @@ rules_setup(int fd)
                kelf = kelf_open(_PATH_KSYMS);
 
        /* Initialize "fake" event for BEGIN/END */
-       bt_devt.dtev_pbn = -1;
+       bt_devt.dtev_pbn = EVENT_BEGIN;
        strlcpy(bt_devt.dtev_comm, getprogname(), sizeof(bt_devt.dtev_comm));
        bt_devt.dtev_pid = getpid();
        bt_devt.dtev_tid = getthrid();
@@ -623,6 +625,7 @@ rules_teardown(int fd)
        uelf = NULL;
 
        /* Update "fake" event for BEGIN/END */
+       bt_devt.dtev_pbn = EVENT_END;
        clock_gettime(CLOCK_REALTIME, &bt_devt.dtev_tsp);
 
        if (rend)
@@ -1600,6 +1603,13 @@ ba2str(struct bt_arg *ba, struct dt_evt *dtev)
                str = buf;
                break;
        case B_AT_BI_PROBE:
+               if (dtev->dtev_pbn == EVENT_BEGIN) {
+                       str = "BEGIN";
+                       break;
+               } else if (dtev->dtev_pbn == EVENT_END) {
+                       str = "END";
+                       break;
+               }
                dtpi = &dt_dtpis[dtev->dtev_pbn - 1];
                if (dtpi != NULL)
                        snprintf(buf, sizeof(buf), "%s:%s:%s",