Add libprocessgroup

libprocessgroup will allow Zygote to place processes
in a cgroup, and then kill the process and all forked processes
later.  lmkd will also kill all forked processes.

Bug: 15313911
Change-Id: I20404d0dbe448f1c475d2f4c61cccca462f9e544

5 files changed, 436 insertions, 0 deletions

diff --git a/libprocessgroup/Android.mk b/libprocessgroup/Android.mk
new file mode 100644
index 0000000..501321f
--- /dev/null
+++ b/libprocessgroup/Android.mk
@@ -0,0 +1,21 @@
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := processgroup.cpp
+LOCAL_MODULE := libprocessgroup
+LOCAL_SHARED_LIBRARIES := liblog
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+LOCAL_CFLAGS := -Wall -Werror
+LOCAL_REQUIRED_MODULE := processgroup_cleanup
+include external/libcxx/libcxx.mk
+include $(BUILD_SHARED_LIBRARY)
+
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := cleanup.cpp
+LOCAL_MODULE := processgroup_cleanup
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
+LOCAL_CFLAGS := -Wall -Werror
+LOCAL_FORCE_STATIC_EXECUTABLE := true
+LOCAL_STATIC_LIBRARIES := libc libcutils
+include $(BUILD_EXECUTABLE)
diff --git a/libprocessgroup/cleanup.cpp b/libprocessgroup/cleanup.cpp
new file mode 100644
index 0000000..cca8dc4
--- /dev/null
+++ b/libprocessgroup/cleanup.cpp
@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2014 Google, Inc
+ *
+ *  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.
+ */
+#include <string.h>
+#include <unistd.h>
+#include <sys/syslimits.h>
+
+#include "processgroup_priv.h"
+
+int main(int argc, char **argv)
+{
+    char buf[PATH_MAX];
+    if (argc != 2)
+        return -1;
+
+    memcpy(buf, PROCESSGROUP_CGROUP_PATH, sizeof(PROCESSGROUP_CGROUP_PATH));
+    strlcat(buf, argv[1], sizeof(buf));
+    return rmdir(buf);
+}
diff --git a/libprocessgroup/include/processgroup/processgroup.h b/libprocessgroup/include/processgroup/processgroup.h
new file mode 100644
index 0000000..11bd8cc
--- /dev/null
+++ b/libprocessgroup/include/processgroup/processgroup.h
@@ -0,0 +1,33 @@
+/*
+ *  Copyright 2014 Google, Inc
+ *
+ *  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.
+ */
+
+#ifndef _PROCESSGROUP_H_
+#define _PROCESSGROUP_H_
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+int killProcessGroup(uid_t uid, int initialPid, int signal);
+
+int createProcessGroup(uid_t uid, int initialPid);
+
+void removeAllProcessGroups(void);
+
+__END_DECLS
+
+#endif
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
new file mode 100644
index 0000000..c32e741
--- /dev/null
+++ b/libprocessgroup/processgroup.cpp
@@ -0,0 +1,316 @@
+/*
+ *  Copyright 2014 Google, Inc
+ *
+ *  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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "libprocessgroup"
+
+#include <assert.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <log/log.h>
+#include <private/android_filesystem_config.h>
+
+#include <processgroup/processgroup.h>
+#include "processgroup_priv.h"
+
+struct ctx {
+    bool initialized;
+    int fd;
+    char buf[128];
+    char *buf_ptr;
+    size_t buf_len;
+};
+
+static int convertUidToPath(char *path, size_t size, uid_t uid)
+{
+    return snprintf(path, size, "%s/%s%d",
+            PROCESSGROUP_CGROUP_PATH,
+            PROCESSGROUP_UID_PREFIX,
+            uid);
+}
+
+static int convertUidPidToPath(char *path, size_t size, uid_t uid, int pid)
+{
+    return snprintf(path, size, "%s/%s%d/%s%d",
+            PROCESSGROUP_CGROUP_PATH,
+            PROCESSGROUP_UID_PREFIX,
+            uid,
+            PROCESSGROUP_PID_PREFIX,
+            pid);
+}
+
+static int initCtx(uid_t uid, int pid, struct ctx *ctx)
+{
+    int ret;
+    char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
+    convertUidPidToPath(path, sizeof(path), uid, pid);
+    strlcat(path, PROCESSGROUP_CGROUP_PROCS_FILE, sizeof(path));
+
+    int fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        ret = -errno;
+        SLOGV("failed to open %s: %s", path, strerror(errno));
+        return ret;
+    }
+
+    ctx->fd = fd;
+    ctx->buf_ptr = ctx->buf;
+    ctx->buf_len = 0;
+    ctx->initialized = true;
+
+    return 0;
+}
+
+static int refillBuffer(struct ctx *ctx)
+{
+    memmove(ctx->buf, ctx->buf_ptr, ctx->buf_len);
+    ctx->buf_ptr = ctx->buf;
+
+    ssize_t ret = read(ctx->fd, ctx->buf_ptr + ctx->buf_len,
+                sizeof(ctx->buf) - ctx->buf_len);
+    if (ret < 0) {
+        return -errno;
+    } else if (ret == 0) {
+        return 0;
+    }
+
+    ctx->buf_len += ret;
+    assert(ctx->buf_len <= sizeof(ctx->buf));
+
+    return ret;
+}
+
+static pid_t getOneAppProcess(uid_t uid, int appProcessPid, struct ctx *ctx)
+{
+    if (!ctx->initialized) {
+        int ret = initCtx(uid, appProcessPid, ctx);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
+    char *eptr;
+    while ((eptr = (char *)memchr(ctx->buf_ptr, '\n', ctx->buf_len)) == NULL) {
+        int ret = refillBuffer(ctx);
+        if (ret == 0) {
+            return -ERANGE;
+        }
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
+    *eptr = '\0';
+    char *pid_eptr = NULL;
+    errno = 0;
+    long pid = strtol(ctx->buf_ptr, &pid_eptr, 10);
+    if (errno != 0) {
+        return -errno;
+    }
+    if (pid_eptr != eptr) {
+        return -EINVAL;
+    }
+
+    ctx->buf_ptr = eptr + 1;
+
+    return (pid_t)pid;
+}
+
+static int removeProcessGroup(uid_t uid, int pid)
+{
+    int ret;
+    char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
+
+    convertUidPidToPath(path, sizeof(path), uid, pid);
+    ret = rmdir(path);
+
+    convertUidToPath(path, sizeof(path), uid);
+    rmdir(path);
+
+    return ret;
+}
+
+static void removeUidProcessGroups(const char *uid_path)
+{
+    DIR *uid = opendir(uid_path);
+    if (uid != NULL) {
+        struct dirent cur;
+        struct dirent *dir;
+        while ((readdir_r(uid, &cur, &dir) == 0) && dir) {
+            char path[PROCESSGROUP_MAX_PATH_LEN];
+
+            if (dir->d_type != DT_DIR) {
+                continue;
+            }
+
+            if (strncmp(dir->d_name, PROCESSGROUP_PID_PREFIX, strlen(PROCESSGROUP_PID_PREFIX))) {
+                continue;
+            }
+
+            snprintf(path, sizeof(path), "%s/%s", uid_path, dir->d_name);
+            SLOGV("removing %s\n", path);
+            rmdir(path);
+        }
+    }
+}
+
+void removeAllProcessGroups()
+{
+    SLOGV("removeAllProcessGroups()");
+    DIR *root = opendir(PROCESSGROUP_CGROUP_PATH);
+    if (root == NULL) {
+        SLOGE("failed to open %s: %s", PROCESSGROUP_CGROUP_PATH, strerror(errno));
+    }
+    if (root != NULL) {
+        struct dirent cur;
+        struct dirent *dir;
+        while ((readdir_r(root, &cur, &dir) == 0) && dir) {
+            char path[PROCESSGROUP_MAX_PATH_LEN];
+
+            if (dir->d_type != DT_DIR) {
+                continue;
+            }
+            if (strncmp(dir->d_name, PROCESSGROUP_UID_PREFIX, strlen(PROCESSGROUP_UID_PREFIX))) {
+                continue;
+            }
+
+            snprintf(path, sizeof(path), "%s/%s", PROCESSGROUP_CGROUP_PATH, dir->d_name);
+            removeUidProcessGroups(path);
+            SLOGV("removing %s\n", path);
+            rmdir(path);
+        }
+    }
+}
+
+static int killProcessGroupOnce(uid_t uid, int initialPid, int signal)
+{
+    int processes = 0;
+    struct ctx ctx;
+    pid_t pid;
+
+    ctx.initialized = false;
+
+    while ((pid = getOneAppProcess(uid, initialPid, &ctx)) >= 0) {
+        processes++;
+        SLOGV("sending processgroup kill to pid %d\n", pid);
+        int ret = kill(pid, signal);
+        if (ret == -1) {
+            SLOGV("failed to kill pid %d: %s", pid, strerror(errno));
+        }
+    }
+
+    if (ctx.initialized) {
+        close(ctx.fd);
+    }
+
+    return processes;
+}
+
+int killProcessGroup(uid_t uid, int initialPid, int signal)
+{
+    int processes;
+    int sleep_us = 100;
+
+    while ((processes = killProcessGroupOnce(uid, initialPid, signal)) > 0) {
+        SLOGV("killed %d processes for processgroup %d\n", processes, initialPid);
+        if (sleep_us < 128000) {
+            usleep(sleep_us);
+            sleep_us *= 2;
+        } else {
+            SLOGE("failed to kill %d processes for processgroup %d\n",
+                    processes, initialPid);
+            break;
+        }
+    }
+
+    if (processes == 0) {
+        return removeProcessGroup(uid, initialPid);
+    } else {
+        return -1;
+    }
+}
+
+static int mkdirAndChown(const char *path, mode_t mode, uid_t uid, gid_t gid)
+{
+    int ret;
+
+    ret = mkdir(path, 0750);
+    if (ret < 0 && errno != EEXIST) {
+        return -errno;
+    }
+
+    ret = chown(path, AID_SYSTEM, AID_SYSTEM);
+    if (ret < 0) {
+        ret = -errno;
+        rmdir(path);
+        return ret;
+    }
+
+    return 0;
+}
+
+int createProcessGroup(uid_t uid, int initialPid)
+{
+    char path[PROCESSGROUP_MAX_PATH_LEN] = {0};
+    int ret;
+
+    convertUidToPath(path, sizeof(path), uid);
+
+    ret = mkdirAndChown(path, 0750, AID_SYSTEM, AID_SYSTEM);
+    if (ret < 0) {
+        SLOGE("failed to make and chown %s: %s", path, strerror(-ret));
+        return ret;
+    }
+
+    convertUidPidToPath(path, sizeof(path), uid, initialPid);
+
+    ret = mkdirAndChown(path, 0750, AID_SYSTEM, AID_SYSTEM);
+    if (ret < 0) {
+        SLOGE("failed to make and chown %s: %s", path, strerror(-ret));
+        return ret;
+    }
+
+    strlcat(path, PROCESSGROUP_CGROUP_PROCS_FILE, sizeof(path));
+
+    int fd = open(path, O_WRONLY);
+    if (fd < 0) {
+        ret = -errno;
+        SLOGE("failed to open %s: %s", path, strerror(errno));
+        return ret;
+    }
+
+    char pid[PROCESSGROUP_MAX_PID_LEN + 1] = {0};
+    int len = snprintf(pid, sizeof(pid), "%d", initialPid);
+
+    ret = write(fd, pid, len);
+    if (ret < 0) {
+        ret = -errno;
+        SLOGE("failed to write '%s' to %s: %s", pid, path, strerror(errno));
+    } else {
+        ret = 0;
+    }
+
+    close(fd);
+    return ret;
+}
+
diff --git a/libprocessgroup/processgroup_priv.h b/libprocessgroup/processgroup_priv.h
new file mode 100644
index 0000000..1895bf9
--- /dev/null
+++ b/libprocessgroup/processgroup_priv.h
@@ -0,0 +1,35 @@
+/*
+ *  Copyright 2014 Google, Inc
+ *
+ *  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.
+ */
+
+#ifndef _PROCESSGROUP_PRIV_H_
+#define _PROCESSGROUP_PRIV_H_
+
+#define PROCESSGROUP_CGROUP_PATH "/acct"
+#define PROCESSGROUP_UID_PREFIX "uid_"
+#define PROCESSGROUP_PID_PREFIX "pid_"
+#define PROCESSGROUP_CGROUP_PROCS_FILE "/cgroup.procs"
+#define PROCESSGROUP_MAX_UID_LEN 11
+#define PROCESSGROUP_MAX_PID_LEN 11
+#define PROCESSGROUP_MAX_PATH_LEN \
+        (sizeof(PROCESSGROUP_CGROUP_PATH) + \
+         sizeof(PROCESSGROUP_UID_PREFIX) + 1 + \
+         PROCESSGROUP_MAX_UID_LEN + \
+         sizeof(PROCESSGROUP_PID_PREFIX) + 1 + \
+         PROCESSGROUP_MAX_PID_LEN + \
+         sizeof(PROCESSGROUP_CGROUP_PROCS_FILE) + \
+         1)
+
+#endif