[linux] swift-inspect support for Linux

tools/swift-inspect/Sources/SwiftInspectLinux/MemoryMap.swift

@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Foundation
+
+public class MemoryMap {
+  public enum Error: Swift.Error {
+    case InvalidProcMapsFile(_ filePath: String)
+  }
+
+  public struct Entry {
+    public let startAddr: UInt64
+    public let endAddr: UInt64
+    public let permissions: String
+    public let offset: UInt64
+    public let device: String
+    public let inode: UInt64
+    public let pathname: String?
+  }
+
+  public let entries: [Entry]
+
+  public init(for pid: pid_t) throws {
+    let filePath = "/proc/\(pid)/maps"
+    let file = try FileHandle(forReadingFrom: URL(fileURLWithPath: filePath))
+    defer { file.closeFile() }
+
+    guard let content = String(data: file.readDataToEndOfFile(), encoding: .ascii) else {
+      throw Error.InvalidProcMapsFile(filePath)
+    }
+
+    var entries: [Entry] = []
+
+    content.enumerateLines { (line, _) in
+      let components = line.split(separator: " ", omittingEmptySubsequences: true)
+      guard components.count >= 5 else { return }
+      let addrParts = components[0].split(separator: "-")
+      let entry = Entry(
+        startAddr: UInt64(addrParts[0], radix: 16) ?? 0,
+        endAddr: UInt64(addrParts[1], radix: 16) ?? 0, permissions: String(components[1]),
+        offset: UInt64(components[2], radix: 16) ?? 0, device: String(components[3]),
+        inode: UInt64(components[4]) ?? 0,
+        pathname: components.count == 6 ? String(components[5]) : nil)
+      entries.append(entry)
+    }
+
+    self.entries = entries
+  }
+
+  public func findEntry(containing addr: UInt64) -> Entry? {
+    // The map array returned by loadMaps will be ordered the same as the
+    // contents of /proc/<pid>/maps, which is in ascending address order.
+    // Binary search it to find the entry containing the target address.
+    var lowerBound = 0
+    var upperBound = self.entries.count
+    while lowerBound < upperBound {
+      let currentIndex = (lowerBound + upperBound) / 2
+      let entry = self.entries[currentIndex]
+      if entry.startAddr > addr {
+        upperBound = currentIndex
+      } else if entry.endAddr <= addr {
+        lowerBound = currentIndex + 1
+      } else {
+        assert(addr >= entry.startAddr)
+        assert(addr < entry.endAddr)
+        return entry
+      }
+    }
+    return nil
+  }
+}