Remove redundant checks in syscall entry/exit, rename badly named function

* syscall.c (syscall_enter): Rename to get_syscall_args.
Document its return values.
(trace_syscall_entering): Don't check get_syscall_args() return
value for 0, it never returns that.
(syscall_fixup_on_sysexit): Make it return void.
(trace_syscall_exiting): Fix up syscall_fixup_on_sysexit()
call site accordingly.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/syscall.c b/syscall.c
index 134be814f6da3607cf29b39e801af5ca5a782134..8d74f6840ac8eab038ecaa5c78e404a2a9ab1fc0 100644 (file)
--- a/syscall.c
+++ b/syscall.c
@@ -1247,8 +1247,9 @@ internal_syscall(struct tcb *tcp)
 #endif
 }
 
+/* Return -1 on error or 1 on success (never 0!) */
 static int
-syscall_enter(struct tcb *tcp)
+get_syscall_args(struct tcb *tcp)
 {
        int i, nargs;
 
@@ -1463,9 +1464,7 @@ trace_syscall_entering(struct tcb *tcp)
        if (res == 0)
                return res;
        if (res == 1)
-               res = syscall_enter(tcp);
-       if (res == 0)
-               return res;
+               res = get_syscall_args(tcp);
 
        if (res != 1) {
                printleader(tcp);
@@ -1639,14 +1638,8 @@ get_syscall_result(struct tcb *tcp)
        return 1;
 }
 
-/* Called at each syscall exit.
- * Returns:
- * 0: "ignore this ptrace stop", bail out of trace_syscall() silently.
- * 1: ok, continue in trace_syscall().
- * other: error, trace_syscall() should print error indicator
- *    ("????" etc) and bail out.
- */
-static int
+/* Called at each syscall exit */
+static void
 syscall_fixup_on_sysexit(struct tcb *tcp)
 {
 #if defined(S390) || defined(S390X)
@@ -1662,7 +1655,6 @@ syscall_fixup_on_sysexit(struct tcb *tcp)
                gpr2 = 0;
        }
 #endif
-       return 1;
 }
 
 /*
@@ -1912,12 +1904,10 @@ trace_syscall_exiting(struct tcb *tcp)
        res = get_syscall_result(tcp);
        if (res == 0)
                return res;
-       if (res == 1)
-               res = syscall_fixup_on_sysexit(tcp);
-       if (res == 0)
-               return res;
-       if (res == 1)
+       if (res == 1) {
+               syscall_fixup_on_sysexit(tcp); /* never fails */
                res = get_error(tcp);
+       }
        if (res == 0)
                return res;
        if (res == 1)