Fix -Wfortify-source compiler warning

dump.cpp:448:13: error: 'snprintf' will always be truncated; specified size is 2, but format string expands to at least 3 [-Werror,-Wfortify-source]
448 |             snprintf(buf, std::size(buf) - 1, "%02x", (unsigned int)b);
    |

Test: presubmit
Change-Id: Ie8d459a048ad8e9ecd95ecfd0d717bd311285dad

1 files changed, 8 insertions, 7 deletions

diff --git a/incfs/incfsdump/dump.cpp b/incfs/incfsdump/dump.cpp
index 35d84ac..523992f 100644
--- a/incfs/incfsdump/dump.cpp
+++ b/incfs/incfsdump/dump.cpp
@@ -37,15 +37,17 @@
 #include <sys/xattr.h>
 #include <unistd.h>
 
-#include "linux/incrementalfs.h"
-
 #include <chrono>
 #include <fstream>
+#include <iomanip>
 #include <iostream>
 #include <iterator>
 #include <optional>
+#include <sstream>
 #include <string_view>
 
+#include "linux/incrementalfs.h"
+
 using namespace std::literals;
 
 namespace {
@@ -442,13 +444,12 @@ private:
     }
 
     static std::string toString(incfs_uuid_t uuid) {
-        std::string res;
+        std::stringstream res;
+        res << std::hex;
         for (unsigned char b : uuid.bytes) {
-            char buf[3] = {};
-            snprintf(buf, std::size(buf) - 1, "%02x", (unsigned int)b);
-            res += buf;
+            res << std::setfill('0') << std::setw(2) << (unsigned int)b;
         }
-        return res;
+        return res.str();
     }
 
     OstreamWrapper out() const {