1 files changed, 115 insertions, 0 deletions
diff --git a/src/mongo/util/pin_code_segments.cpp b/src/mongo/util/pin_code_segments.cpp
new file mode 100644
index 00000000000..8d685d86d1d
--- /dev/null
+++ b/src/mongo/util/pin_code_segments.cpp
@@ -0,0 +1,115 @@
+/**
+ *    Copyright (C) 2023-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kControl
+
+#include <elf.h>
+#include <link.h>
+#include <sys/mman.h>
+#include <vector>
+
+#include "mongo/db/initialize_server_global_state.h"
+#include "mongo/db/initialize_server_global_state_gen.h"
+#include "mongo/logv2/log.h"
+#include "mongo/util/hex.h"
+#include "mongo/util/pin_code_segments_params_gen.h"
+
+namespace mongo {
+namespace {
+
+using ElfWEhdr = ElfW(Ehdr);
+using ElfWHalf = ElfW(Half);
+using ElfWPhdr = ElfW(Phdr);
+
+struct CodeSegment {
+    void* addr;
+    size_t memSize;
+};
+
+int appendCodeSegments(dl_phdr_info* info, size_t size, void* data) {
+    auto segments = reinterpret_cast<std::vector<CodeSegment>*>(data);
+    for (ElfWHalf i = 0; i < info->dlpi_phnum; ++i) {
+        const ElfWPhdr& phdr(info->dlpi_phdr[i]);
+        if (phdr.p_type != PT_LOAD) {
+            // Code segments must be of LOAD type.
+            continue;
+        }
+        const auto f = phdr.p_flags;
+        if (!(f & PF_R)) {
+            // Code segments have read permissions so exclude segments that do not.
+            continue;
+        }
+        if (!(f & PF_X)) {
+            // Code segments have execute permissions so exclude segments that do not.
+            continue;
+        }
+        if (f & PF_W) {
+            // Code segments don't have write permissions so exclude segments that do.
+            continue;
+        }
+        segments->push_back(
+            {reinterpret_cast<void*>(info->dlpi_addr + phdr.p_vaddr), phdr.p_memsz});
+    }
+    return 0;
+}
+
+std::vector<CodeSegment> getCodeSegments() {
+    std::vector<CodeSegment> segments;
+    dl_iterate_phdr(appendCodeSegments, &segments);
+    return segments;
+}
+
+MONGO_INITIALIZER(PinCodeSegments)(InitializerContext*) {
+    if (!gLockCodeSegmentsInMemory) {
+        return;
+    }
+    LOGV2(7394303, "Pinning code segments");
+    size_t lockedMemSize = 0;
+    auto codeSegments = getCodeSegments();
+    for (auto&& segment : codeSegments) {
+        if (mlock(segment.addr, segment.memSize) != 0) {
+            auto ec = lastSystemError();
+            LOGV2_FATAL(
+                7394301,
+                "Failed to lock code segment, ensure system ulimits are properly configured",
+                "error"_attr = errorMessage(ec),
+                "address"_attr = unsignedHex(reinterpret_cast<uintptr_t>(segment.addr)),
+                "memSize"_attr = segment.memSize,
+                "memLockedSoFar"_attr = lockedMemSize);
+        }
+        lockedMemSize += segment.memSize;
+    }
+    LOGV2(7394302,
+          "Successfully locked code segments into memory",
+          "numSegments"_attr = codeSegments.size(),
+          "totalLockedMemSize"_attr = lockedMemSize);
+}
+
+}  // namespace
+}  // namespace mongo