SERVER-115392 Enable hardening-related compiler warnings (#45209)

GitOrigin-RevId: aebabea966cc7aad2030976f6629b4aea6f9a2d6

bazel/mongo_src_rules.bzl

@@ -203,10 +203,13 @@ DISABLE_3RD_PARTY_FEATURES = select({
     "//bazel/config:compiler_type_clang": [
         "-disable_warnings_for_third_party_libraries_clang",
         "thread_safety_warnings",
+        "first_party_gcc_or_clang_warnings",
         "-ubsan_third_party",
     ],
     "//bazel/config:compiler_type_gcc": [
         "-disable_warnings_for_third_party_libraries_gcc",
+        "first_party_gcc_or_clang_warnings",
+        "first_party_gcc_warnings",
         "-ubsan_third_party",
     ],
     "//conditions:default": [],
@@ -379,7 +382,8 @@ def mongo_cc_library(
 
         if name != "mongoca" and name != "cyrus_sasl_windows_test_plugin":
             deps += MONGO_GLOBAL_SRC_DEPS
-        features = features + DISABLE_3RD_PARTY_FEATURES
+        if not in_third_party:
+            features = features + DISABLE_3RD_PARTY_FEATURES
     else:
         srcs = _final_srcs_for_cc + private_hdrs
 
@@ -585,7 +589,8 @@ def _mongo_cc_binary_and_test(
             srcs = _final_srcs_for_cc + private_hdrs
 
         deps += MONGO_GLOBAL_SRC_DEPS
-        features = features + DISABLE_3RD_PARTY_FEATURES
+        if not in_third_party:
+            features = features + DISABLE_3RD_PARTY_FEATURES
     else:
         # Non-mongo pkgs: append private headers as sources
         srcs = _final_srcs_for_cc + private_hdrs

bazel/toolchains/cc/mongo_linux/mongo_linux_cc_toolchain_config.bzl

@@ -939,6 +939,9 @@ def _impl(ctx):
                     # compilers GCC >= 4.6. Error explained in
                     # https://svn.boost.org/trac/boost/ticket/6136 .
                     "-Wno-unused-but-set-variable",
+
+                    # Warn about trampolines that require executable stacks.
+                    "-Wtrampolines",
                 ])],
             ),
         ],
@@ -1723,6 +1726,38 @@ def _impl(ctx):
         ],
     )
 
+    first_party_gcc_or_clang_warnings_feature = feature(
+        name = "first_party_gcc_or_clang_warnings",
+        enabled = False,
+        flag_sets = [
+            flag_set(
+                actions = all_compile_actions,
+                flag_groups = [flag_group(flags = [
+                    # Warn about issues with format strings. Using both -Wformat and -Wformat=2
+                    # is necessary to get all the format string warnings in both gcc and clang.
+                    # Specifically, in clang -Wformat=2 does not imply -Wformat.
+                    "-Wformat",
+                    "-Wformat=2",
+                ])],
+            ),
+        ],
+    )
+
+    first_party_gcc_warnings_feature = feature(
+        name = "first_party_gcc_warnings",
+        enabled = False,
+        flag_sets = [
+            flag_set(
+                actions = all_compile_actions,
+                flag_groups = [flag_group(flags = [
+                    # Warn about bidirectional control characters that could be used for
+                    # underhanded code.
+                    "-Wbidi-chars=any",
+                ])],
+            ),
+        ],
+    )
+
     disable_warnings_for_third_party_libraries_clang_feature = feature(
         name = "disable_warnings_for_third_party_libraries_clang",
         enabled = ctx.attr.compiler == COMPILERS.CLANG,
@@ -1857,6 +1892,8 @@ def _impl(ctx):
         compress_debug_disable_feature,
         rpath_override_feature,
         warnings_as_errors_link_feature,
+        first_party_gcc_or_clang_warnings_feature,
+        first_party_gcc_warnings_feature,
     ] + get_common_features(ctx) + [
         # These flags are at the bottom so they get applied after anything else.
         # These are things like the flags people apply directly on cc_library through copts/linkopts

src/mongo/bson/util/builder.h

@@ -64,6 +64,7 @@
 #include <boost/optional.hpp>
 #include <boost/optional/optional.hpp>
 #include <boost/static_assert.hpp>
+#include <fmt/format.h>
 
 namespace mongo {
 
@@ -749,7 +750,7 @@ public:
     StringBuilderImpl() {}
 
     StringBuilderImpl& operator<<(double x) {
-        return SBNUM(x, MONGO_DBL_SIZE, "%g");
+        return appendUsingFmt(x, MONGO_DBL_SIZE);
     }
     StringBuilderImpl& operator<<(int x) {
         return appendIntegral(x, MONGO_S32_SIZE);
@@ -773,11 +774,7 @@ public:
         return appendIntegral(x, MONGO_S16_SIZE);
     }
     StringBuilderImpl& operator<<(const void* x) {
-        if (sizeof(x) == 8) {
-            return SBNUM(x, MONGO_PTR_SIZE, "0x%llX");
-        } else {
-            return SBNUM(x, MONGO_PTR_SIZE, "0x%lX");
-        }
+        return appendUsingFmt(x, MONGO_PTR_SIZE);
     }
     StringBuilderImpl& operator<<(bool val) {
         *_buf.grow(1) = val ? '1' : '0';
@@ -876,13 +873,22 @@ private:
         return *this;
     }
 
+    size_t writeUsingFmt(char* dst, size_t maxSize, double val) {
+        return fmt::format_to_n(dst, maxSize, "{:g}", val).size;
+    }
+
+    size_t writeUsingFmt(char* dst, size_t maxSize, const void* val) {
+        return fmt::format_to_n(dst, maxSize, "0x{:X}", uintptr_t(val)).size;
+    }
+
     template <typename T>
-    StringBuilderImpl& SBNUM(T val, int maxSize, const char* macro) {
-        int prev = _buf.len();
-        int z = snprintf(_buf.grow(maxSize), maxSize, macro, (val));
-        MONGO_verify(z >= 0);
-        MONGO_verify(z < maxSize);
-        _buf.setlen(prev + z);
+    StringBuilderImpl& appendUsingFmt(T val, size_t maxSize) {
+        static_assert(std::is_same_v<T, const void*> || std::is_same_v<T, double>);
+        size_t prev = _buf.len();
+        size_t size = writeUsingFmt(_buf.grow(maxSize), maxSize, val);
+        MONGO_verify(size >= 0);
+        MONGO_verify(size < maxSize);
+        _buf.setlen(prev + size);
         return *this;
     }
 

src/mongo/bson/util/builder_test.cpp

@@ -118,6 +118,22 @@ TEST(Builder, StackAllocatorShouldNotLeak) {
     // Let the builder go out of scope. If this leaks, it will trip the ASAN leak detector.
 }
 
+TEST(Builder, StringBuilderFloatingPointExponentNotation) {
+    StringBuilder sb;
+    sb << 1000000.23456789;
+    ASSERT_EQUALS("1e+06", sb.str());
+
+    sb.reset();
+    sb << 1234567.89;
+    ASSERT_EQUALS("1.23457e+06", sb.str());
+}
+
+TEST(Builder, StringBuilderFloatingPointPrecision) {
+    StringBuilder sb;
+    sb << 1.23456789;
+    ASSERT_EQUALS("1.23457", sb.str());
+}
+
 template <typename T>
 void testStringBuilderIntegral() {
     auto check = [](T num) {

src/mongo/util/time_support.cpp

@@ -165,19 +165,17 @@ std::string time_t_to_String_short(time_t t) {
     return buf;
 }
 
-constexpr auto kUTCFilenameFormat = "%Y-%m-%dT%H-%M-%S"_sd;
-constexpr auto kUTCFilenameFormatZ = "%Y-%m-%dT%H-%M-%SZ"_sd;
-
 // Produces a UTC datetime string suitable for use in filenames.
 std::string terseCurrentTimeForFilename(bool appendZed) {
     struct tm t;
     time_t_to_Struct(time(nullptr), &t);
 
-    const auto fmt = appendZed ? kUTCFilenameFormatZ : kUTCFilenameFormat;
     const std::size_t expLen = appendZed ? 20 : 19;
 
     char buf[32];
-    fassert(16226, strftime(buf, sizeof(buf), fmt.data(), &t) == expLen);
+    size_t bytesWritten =
+        strftime(buf, sizeof(buf), appendZed ? "%Y-%m-%dT%H-%M-%SZ" : "%Y-%m-%dT%H-%M-%S", &t);
+    fassert(16226, bytesWritten == expLen);
     return buf;
 }