Add a comment about setbpt. No code changes.

* defs.h: Add a comment about setbpt().

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

diff --git a/defs.h b/defs.h
index c1c31793056e78ad7c7acfa31c4283cf1d149698..0632a7505e71cb768e005162609f86458b3e7747 100644 (file)
--- a/defs.h
+++ b/defs.h
@@ -566,6 +566,12 @@ extern void print_sock_optmgmt(struct tcb *, long, int);
 extern void printrusage(struct tcb *, long);
 extern void printuid(const char *, unsigned long);
 extern int clearbpt(struct tcb *);
+/*
+ * On Linux, "setbpt" is a misnomer: we don't set a breakpoint
+ * (IOW: no poking in user's text segment),
+ * instead we change fork/vfork/clone into clone(CLONE_PTRACE).
+ * On newer kernels, we use PTRACE_O_TRACECLONE/TRACE[V]FORK instead.
+ */
 extern int setbpt(struct tcb *);
 extern int sigishandled(struct tcb *, int);
 extern void printcall(struct tcb *);