From 0a7603c097e9ac8845a51808aef35978fa6f0cfb Mon Sep 17 00:00:00 2001
From: Jiakai Zhang <jiakaiz@google.com>
Date: Mon, 21 Feb 2022 19:38:14 +0000
Subject: Add a timeout for all installd operations.

Bug: 216514270
Test: atest installd_utils_test
Test: atest installd_dexopt_test
Change-Id: I6c25e1df756ca486de1c8611185dbedf60d7cd7d
Merged-In: I6c25e1df756ca486de1c8611185dbedf60d7cd7d
(cherry picked from commit 495142ac75cdb2595a61755d7ab42a748e651728)
---
 cmds/installd/utils.cpp | 78 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 59 insertions(+), 19 deletions(-)

(limited to 'cmds/installd/utils.cpp')

diff --git a/cmds/installd/utils.cpp b/cmds/installd/utils.cpp
index faccded34b..f04ee337d9 100644
--- a/cmds/installd/utils.cpp
+++ b/cmds/installd/utils.cpp
@@ -19,18 +19,21 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <fts.h>
+#include <poll.h>
 #include <stdlib.h>
 #include <sys/capability.h>
+#include <sys/pidfd.h>
 #include <sys/stat.h>
 #include <sys/statvfs.h>
 #include <sys/wait.h>
 #include <sys/xattr.h>
+#include <unistd.h>
 #include <uuid/uuid.h>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
-#include <android-base/strings.h>
 #include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <cutils/fs.h>
 #include <cutils/properties.h>
@@ -1059,30 +1062,45 @@ int ensure_config_user_dirs(userid_t userid) {
     return fs_prepare_dir(path.c_str(), 0750, uid, gid);
 }
 
-int wait_child(pid_t pid)
-{
+static int wait_child(pid_t pid) {
     int status;
-    pid_t got_pid;
+    pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, /*options=*/0));
 
-    while (1) {
-        got_pid = waitpid(pid, &status, 0);
-        if (got_pid == -1 && errno == EINTR) {
-            printf("waitpid interrupted, retrying\n");
-        } else {
-            break;
-        }
-    }
     if (got_pid != pid) {
-        ALOGW("waitpid failed: wanted %d, got %d: %s\n",
-            (int) pid, (int) got_pid, strerror(errno));
-        return 1;
+        PLOG(ERROR) << "waitpid failed: wanted " << pid << ", got " << got_pid;
+        return W_EXITCODE(/*exit_code=*/255, /*signal_number=*/0);
     }
 
-    if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
-        return 0;
-    } else {
-        return status;      /* always nonzero */
+    return status;
+}
+
+int wait_child_with_timeout(pid_t pid, int timeout_ms) {
+    int pidfd = pidfd_open(pid, /*flags=*/0);
+    if (pidfd < 0) {
+        PLOG(ERROR) << "pidfd_open failed for pid " << pid;
+        kill(pid, SIGKILL);
+        return wait_child(pid);
+    }
+
+    struct pollfd pfd;
+    pfd.fd = pidfd;
+    pfd.events = POLLIN;
+    int poll_ret = TEMP_FAILURE_RETRY(poll(&pfd, /*nfds=*/1, timeout_ms));
+
+    close(pidfd);
+
+    if (poll_ret < 0) {
+        PLOG(ERROR) << "poll failed for pid " << pid;
+        kill(pid, SIGKILL);
+        return wait_child(pid);
     }
+    if (poll_ret == 0) {
+        LOG(WARNING) << "Child process " << pid << " timed out after " << timeout_ms
+                     << "ms. Killing it";
+        kill(pid, SIGKILL);
+        return wait_child(pid);
+    }
+    return wait_child(pid);
 }
 
 /**
@@ -1295,5 +1313,27 @@ void drop_capabilities(uid_t uid) {
     }
 }
 
+bool remove_file_at_fd(int fd, /*out*/ std::string* path) {
+    char path_buffer[PATH_MAX + 1];
+    std::string proc_path = android::base::StringPrintf("/proc/self/fd/%d", fd);
+    ssize_t len = readlink(proc_path.c_str(), path_buffer, PATH_MAX);
+    if (len < 0) {
+        PLOG(WARNING) << "Could not remove file at fd " << fd << ": Failed to get file path";
+        return false;
+    }
+    path_buffer[len] = '\0';
+    if (path != nullptr) {
+        *path = path_buffer;
+    }
+    if (unlink(path_buffer) != 0) {
+        if (errno == ENOENT) {
+            return true;
+        }
+        PLOG(WARNING) << "Could not remove file at path " << path_buffer;
+        return false;
+    }
+    return true;
+}
+
 }  // namespace installd
 }  // namespace android
-- 
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