1 files changed, 261 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/exec/apple/XcodeLocalEnvProvider.java b/src/main/java/com/google/devtools/build/lib/exec/apple/XcodeLocalEnvProvider.java
new file mode 100644
index 0000000000..55a2ba5ddc
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/exec/apple/XcodeLocalEnvProvider.java
@@ -0,0 +1,261 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.exec.apple;
+
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+import com.google.devtools.build.lib.analysis.BlazeDirectories;
+import com.google.devtools.build.lib.exec.local.LocalEnvProvider;
+import com.google.devtools.build.lib.rules.apple.AppleConfiguration;
+import com.google.devtools.build.lib.rules.apple.DottedVersion;
+import com.google.devtools.build.lib.shell.AbnormalTerminationException;
+import com.google.devtools.build.lib.shell.Command;
+import com.google.devtools.build.lib.shell.CommandException;
+import com.google.devtools.build.lib.shell.CommandResult;
+import com.google.devtools.build.lib.shell.TerminationStatus;
+import com.google.devtools.build.lib.util.OS;
+import com.google.devtools.build.lib.vfs.Path;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+/**
+ * Adds to the given environment all variables that are dependent on system state of the host
+ * machine.
+ *
+ * <p>Admittedly, hermeticity is "best effort" in such cases; these environment values should be as
+ * tied to configuration parameters as possible.
+ *
+ * <p>For example, underlying iOS toolchains require that SDKROOT resolve to an absolute system
+ * path, but, when selecting which SDK to resolve, the version number comes from build
+ * configuration.
+ */
+public final class XcodeLocalEnvProvider implements LocalEnvProvider {
+  private static final String XCRUN_CACHE_FILENAME = "__xcruncache";
+  private static final String XCODE_LOCATOR_CACHE_FILENAME = "__xcodelocatorcache";
+
+  private final String productName;
+  private final Map<String, String> clientEnv;
+
+  /**
+   * Creates a new {@link XcodeLocalEnvProvider}.
+   *
+   * @param clientEnv a map of the current Bazel command's environment
+   */
+  public XcodeLocalEnvProvider(String productName, Map<String, String> clientEnv) {
+    this.productName = productName;
+    this.clientEnv = clientEnv;
+  }
+
+  @Override
+  public Map<String, String> rewriteLocalEnv(
+      Map<String, String> env, Path execRoot, String fallbackTmpDir) throws IOException {
+    boolean containsXcodeVersion = env.containsKey(AppleConfiguration.XCODE_VERSION_ENV_NAME);
+    boolean containsAppleSdkVersion =
+        env.containsKey(AppleConfiguration.APPLE_SDK_VERSION_ENV_NAME);
+
+    ImmutableMap.Builder<String, String> newEnvBuilder = ImmutableMap.builder();
+    newEnvBuilder.putAll(Maps.filterKeys(env, k -> !k.equals("TMPDIR")));
+    String p = clientEnv.get("TMPDIR");
+    if (Strings.isNullOrEmpty(p)) {
+      // Do not use `fallbackTmpDir`, use `/tmp` instead. This way if the user didn't export TMPDIR
+      // in their environment, Bazel will still set a TMPDIR that's Posixy enough and plays well
+      // with heavily path-length-limited scenarios, such as the socket creation scenario that
+      // motivated https://github.com/bazelbuild/bazel/issues/4376.
+      p = "/tmp";
+    }
+    newEnvBuilder.put("TMPDIR", p);
+
+    if (!containsXcodeVersion && !containsAppleSdkVersion) {
+      return newEnvBuilder.build();
+    }
+
+    // Empty developer dir indicates to use the system default.
+    // TODO(bazel-team): Bazel's view of the xcode version and developer dir should be explicitly
+    // set for build hermeticity.
+    String developerDir = "";
+    if (containsXcodeVersion) {
+      String version = env.get(AppleConfiguration.XCODE_VERSION_ENV_NAME);
+      developerDir = getDeveloperDir(execRoot, DottedVersion.fromString(version), productName);
+      newEnvBuilder.put("DEVELOPER_DIR", developerDir);
+    }
+    if (containsAppleSdkVersion) {
+      // The Apple platform is needed to select the appropriate SDK.
+      if (!env.containsKey(AppleConfiguration.APPLE_SDK_PLATFORM_ENV_NAME)) {
+        throw new IOException("Could not resolve apple platform for determining SDK");
+      }
+      String iosSdkVersion = env.get(AppleConfiguration.APPLE_SDK_VERSION_ENV_NAME);
+      String appleSdkPlatform = env.get(AppleConfiguration.APPLE_SDK_PLATFORM_ENV_NAME);
+      newEnvBuilder.put(
+          "SDKROOT",
+          getSdkRoot(execRoot, developerDir, iosSdkVersion, appleSdkPlatform, productName));
+    }
+
+    return newEnvBuilder.build();
+  }
+
+  /**
+   * Returns the absolute root path of the target Apple SDK on the host system for a given version
+   * of xcode (as defined by the given {@code developerDir}). This may spawn a process and use the
+   * {@code /usr/bin/xcrun} binary to locate the target SDK. This uses a local cache file under
+   * {@code bazel-out}, and will only spawn a new {@code xcrun} process in the case of a cache miss.
+   *
+   * @param execRoot the execution root path, used to locate the cache file
+   * @param developerDir the value of {@code DEVELOPER_DIR} for the target version of xcode
+   * @param sdkVersion the sdk version, for example, "9.1"
+   * @param appleSdkPlatform the sdk platform, for example, "iPhoneOS"
+   * @param productName the product name
+   * @throws IOException if there is an issue with obtaining the root from the spawned process,
+   *     either because the SDK platform/version pair doesn't exist, or there was an unexpected
+   *     issue finding or running the tool
+   */
+  private static String getSdkRoot(
+      Path execRoot,
+      String developerDir,
+      String sdkVersion,
+      String appleSdkPlatform,
+      String productName)
+      throws IOException {
+    if (OS.getCurrent() != OS.DARWIN) {
+      throw new IOException("Cannot locate iOS SDK on non-darwin operating system");
+    }
+    try {
+      CacheManager cacheManager =
+          new CacheManager(
+              execRoot.getRelative(BlazeDirectories.getRelativeOutputPath(productName)),
+              XCRUN_CACHE_FILENAME);
+
+      String sdkString = appleSdkPlatform.toLowerCase() + sdkVersion;
+      String cacheResult = cacheManager.getValue(developerDir, sdkString);
+      if (cacheResult != null) {
+        return cacheResult;
+      } else {
+        Map<String, String> env =
+            Strings.isNullOrEmpty(developerDir)
+                ? ImmutableMap.<String, String>of()
+                : ImmutableMap.of("DEVELOPER_DIR", developerDir);
+        CommandResult xcrunResult =
+            new Command(
+                    new String[] {"/usr/bin/xcrun", "--sdk", sdkString, "--show-sdk-path"},
+                    env,
+                    null)
+                .execute();
+
+        // calling xcrun via Command returns a value with a newline on the end.
+        String sdkRoot = new String(xcrunResult.getStdout(), StandardCharsets.UTF_8).trim();
+
+        cacheManager.writeEntry(ImmutableList.of(developerDir, sdkString), sdkRoot);
+        return sdkRoot;
+      }
+    } catch (AbnormalTerminationException e) {
+      TerminationStatus terminationStatus = e.getResult().getTerminationStatus();
+
+      if (terminationStatus.exited()) {
+        throw new IOException(
+            String.format(
+                "xcrun failed with code %s.\n"
+                    + "This most likely indicates that SDK version [%s] for platform [%s] is "
+                    + "unsupported for the target version of xcode.\n"
+                    + "%s\n"
+                    + "Stderr: %s",
+                terminationStatus.getExitCode(),
+                sdkVersion,
+                appleSdkPlatform,
+                terminationStatus.toString(),
+                new String(e.getResult().getStderr(), StandardCharsets.UTF_8)));
+      }
+      String message =
+          String.format(
+              "xcrun failed.\n%s\n%s",
+              e.getResult().getTerminationStatus(),
+              new String(e.getResult().getStderr(), StandardCharsets.UTF_8));
+      throw new IOException(message, e);
+    } catch (CommandException e) {
+      throw new IOException(e);
+    }
+  }
+
+  /**
+   * Returns the absolute root path of the xcode developer directory on the host system for the
+   * given xcode version. This may spawn a process and use the {@code xcode-locator} binary. This
+   * uses a local cache file under {@code bazel-out}, and will only spawn a new process in the case
+   * of a cache miss.
+   *
+   * @param execRoot the execution root path, used to locate the cache file
+   * @param version the xcode version number to look up
+   * @param productName the product name
+   * @throws IOException if there is an issue with obtaining the path from the spawned process,
+   *     either because there is no installed xcode with the given version, or there was an
+   *     unexpected issue finding or running the tool
+   */
+  private static String getDeveloperDir(Path execRoot, DottedVersion version, String productName)
+      throws IOException {
+    if (OS.getCurrent() != OS.DARWIN) {
+      throw new IOException(
+          "Cannot locate xcode developer directory on non-darwin operating system");
+    }
+    try {
+      CacheManager cacheManager =
+          new CacheManager(
+              execRoot.getRelative(BlazeDirectories.getRelativeOutputPath(productName)),
+              XCODE_LOCATOR_CACHE_FILENAME);
+
+      String cacheResult = cacheManager.getValue(version.toString());
+      if (cacheResult != null) {
+        return cacheResult;
+      } else {
+        CommandResult xcodeLocatorResult =
+            new Command(
+                    new String[] {
+                      execRoot.getRelative("_bin/xcode-locator").getPathString(), version.toString()
+                    })
+                .execute();
+
+        String developerDir =
+            new String(xcodeLocatorResult.getStdout(), StandardCharsets.UTF_8).trim();
+
+        cacheManager.writeEntry(ImmutableList.of(version.toString()), developerDir);
+        return developerDir;
+      }
+    } catch (AbnormalTerminationException e) {
+      TerminationStatus terminationStatus = e.getResult().getTerminationStatus();
+
+      String message;
+      if (e.getResult().getTerminationStatus().exited()) {
+        message =
+            String.format(
+                "xcode-locator failed with code %s.\n"
+                    + "This most likely indicates that xcode version %s is not available on the "
+                    + "host machine.\n"
+                    + "%s\n"
+                    + "stderr: %s",
+                terminationStatus.getExitCode(),
+                version,
+                terminationStatus.toString(),
+                new String(e.getResult().getStderr(), StandardCharsets.UTF_8));
+      } else {
+        message =
+            String.format(
+                "xcode-locator failed. %s\nstderr: %s",
+                e.getResult().getTerminationStatus(),
+                new String(e.getResult().getStderr(), StandardCharsets.UTF_8));
+      }
+      throw new IOException(message, e);
+    } catch (CommandException e) {
+      throw new IOException(e);
+    }
+  }
+}