From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Tue, 20 Mar 2012 16:10:35 +0000 (+0100)
Subject: Remove redundant checks in syscall entry/exit, rename badly named function
X-Git-Tag: v4.7~51
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bb6bb5c17992bbfdff902a4729296d0ddb4aa54a;p=strace

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 134be814..8d74f684 100644
--- 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)