[lxc-devel] [lxc/master] conf: fix clang warning when building w/o libcap

[igalic on Github]

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From 8560cd364bab452ed61d24df0674769b5a38de4a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Igor=20Gali=C4=87?= <igor.galic at automatic-server.com>
Date: Wed, 14 Mar 2018 16:53:24 +0100
Subject: [PATCH] conf: fix clang warning when building w/o libcap
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when compiling lxc with clang-5.0 parse_cap()'s main loop will produce a
warning about a tautological comparision (#2215).

By moving the result of computation into a variable (end) this is no
longer a constant expression. clang-5.0 does not do dataflow analysis at
this point, so it is, to quote someone from #llvm, "morally equivalent"
to casting `(int)i`.

in addition, we also clean up the #if HAVE_LIBCAP to no longer need
its #else branch!

Signed-off-by: Igor Galić <igor.galic at automatic-server.com>
---
 src/lxc/conf.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index a6635a348..0d399a73b 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -205,8 +205,8 @@ static struct mount_opt propagation_opt[] = {
 	{ NULL,            0, 0                    },
 };
 
-#if HAVE_LIBCAP
 static struct caps_opt caps_opt[] = {
+#if HAVE_LIBCAP
 	{ "chown",             CAP_CHOWN             },
 	{ "dac_override",      CAP_DAC_OVERRIDE      },
 	{ "dac_read_search",   CAP_DAC_READ_SEARCH   },
@@ -257,10 +257,8 @@ static struct caps_opt caps_opt[] = {
 #ifdef CAP_BLOCK_SUSPEND
 	{ "block_suspend",     CAP_BLOCK_SUSPEND     },
 #endif
-};
-#else
-static struct caps_opt caps_opt[] = {};
 #endif
+};
 
 static struct limit_opt limit_opt[] = {
 #ifdef RLIMIT_AS
@@ -2359,11 +2357,12 @@ static int parse_cap(const char *cap)
 	char *ptr = NULL;
 	size_t i;
 	int capid = -1;
+	size_t end = sizeof(caps_opt)/sizeof(caps_opt[0]);
 
 	if (!strcmp(cap, "none"))
 		return -2;
 
-	for (i = 0; i < sizeof(caps_opt)/sizeof(caps_opt[0]); i++) {
+	for (i = 0; i < end; i++) {
 
 		if (strcmp(cap, caps_opt[i].name))
 			continue;