From 7701548a6a1d131e642e74ef39a5a38093023b3f Mon Sep 17 00:00:00 2001
From: louhongxiang <louhongxiang@huawei.com>
Date: Mon, 10 May 2021 20:31:23 +0800
Subject: [PATCH 25/50] add support for systemctl mode to start etmem

---
 inc/etmemd_inc/etmemd_common.h |  7 ++-
 inc/etmemd_inc/etmemd_rpc.h    |  1 +
 inc/etmemd_inc/etmemd_task.h   |  3 --
 src/etmemd_src/etmemd_common.c |  7 ++-
 src/etmemd_src/etmemd_rpc.c    | 80 ++++++++++++++++++++++++++++++++++
 src/etmemd_src/etmemd_task.c   |  4 +-
 6 files changed, 95 insertions(+), 7 deletions(-)

diff --git a/inc/etmemd_inc/etmemd_common.h b/inc/etmemd_inc/etmemd_common.h
index 1b62bbd..e228476 100644
--- a/inc/etmemd_inc/etmemd_common.h
+++ b/inc/etmemd_inc/etmemd_common.h
@@ -23,10 +23,15 @@
 #define FILE_LINE_MAX_LEN 1024
 #define KEY_VALUE_MAX_LEN 64
 #define DECIMAL_RADIX 10
-#define ETMEMD_MAX_PARAMETER_NUM 5
+#define ETMEMD_MAX_PARAMETER_NUM 6
 
 #define ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
 
+/* in some system the max length of pid may be larger than 5, so we use 10 herr */
+#define PID_STR_MAX_LEN 10
+
+#define PIPE_FD_LEN 2
+
 /*
  * function: parse cmdline passed to etmemd server.
  *
diff --git a/inc/etmemd_inc/etmemd_rpc.h b/inc/etmemd_inc/etmemd_rpc.h
index 146cec3..aa0a49b 100644
--- a/inc/etmemd_inc/etmemd_rpc.h
+++ b/inc/etmemd_inc/etmemd_rpc.h
@@ -55,5 +55,6 @@ int etmemd_parse_sock_name(const char *sock_name);
 int etmemd_rpc_server(void);
 bool etmemd_sock_name_set(void);
 void etmemd_sock_name_free(void);
+int etmemd_deal_systemctl(void);
 
 #endif
diff --git a/inc/etmemd_inc/etmemd_task.h b/inc/etmemd_inc/etmemd_task.h
index be3ade3..29e8e8f 100644
--- a/inc/etmemd_inc/etmemd_task.h
+++ b/inc/etmemd_inc/etmemd_task.h
@@ -23,9 +23,6 @@
 #include "etmemd_threadtimer.h"
 #include "etmemd_task_exp.h"
 
-/* in some system the max length of pid may be larger than 5, so we use 10 here */
-#define PID_STR_MAX_LEN 10
-
 struct task_pid {
     unsigned int pid;
     float rt_swapin_rate;   /* real time swapin rate */
diff --git a/src/etmemd_src/etmemd_common.c b/src/etmemd_src/etmemd_common.c
index 4b9c4cb..155a64b 100644
--- a/src/etmemd_src/etmemd_common.c
+++ b/src/etmemd_src/etmemd_common.c
@@ -37,6 +37,7 @@ static void usage(void)
            "\noptions:\n"
            "    -l|--log-level <log-level>  Log level\n"
            "    -s|--socket <sockect name>  Socket name to listen to\n"
+           "    -m|--mode-systemctl         mode used to start(systemctl)\n"        
            "    -h|--help                   Show this message\n");
 }
 
@@ -66,6 +67,9 @@ static int etmemd_parse_opts_valid(int opt, bool *is_help)
             *is_help = true;
             usage();
             break;
+        case 'm':
+            ret = etmemd_deal_systemctl();
+            break;
         case '?':
             printf("error: parse parameters failed\n");
             /* fallthrough */
@@ -99,12 +103,13 @@ static int etmemd_parse_check_result(int params_cnt, int argc, const bool *is_he
 
 int etmemd_parse_cmdline(int argc, char *argv[], bool *is_help)
 {
-    const char *op_str = "s:l:h";
+    const char *op_str = "s:l:mh";
     int params_cnt = 0;
     int opt, ret;
     struct option long_options[] = {
         {"socket", required_argument, NULL, 's'},
         {"log-level", required_argument, NULL, 'l'},
+        {"mode-systemctl", no_argument, NULL, 'm'},
         {"help", no_argument, NULL, 'h'},
         {NULL, 0, NULL, 0},
     };
diff --git a/src/etmemd_src/etmemd_rpc.c b/src/etmemd_src/etmemd_rpc.c
index 8360f5a..ba5971c 100644
--- a/src/etmemd_src/etmemd_rpc.c
+++ b/src/etmemd_src/etmemd_rpc.c
@@ -19,6 +19,9 @@
 #include <sys/socket.h>
 #include <signal.h>
 #include <glib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include "securec.h"
 #include "etmemd_rpc.h"
 #include "etmemd_project.h"
@@ -35,6 +38,8 @@
 static bool g_exit = true;
 static char *g_sock_name = NULL;
 static int g_sock_fd;
+static int g_fd[PIPE_FD_LEN];
+static int g_use_systemctl = 0;
 struct server_rpc_params g_rpc_params;
 
 struct rpc_resp_msg {
@@ -67,6 +72,12 @@ struct rpc_resp_msg g_resp_msg_arr[] = {
     {OPT_RET_END, NULL},
 };
 
+int etmemd_deal_systemctl(void)
+{
+    g_use_systemctl = 1;
+    return 0;
+}
+
 static void etmemd_set_flag(int s)
 {
     etmemd_log(ETMEMD_LOG_ERR, "caught signal %d\n", s);
@@ -637,8 +648,69 @@ RPC_EXIT:
     return ret;
 }
 
+static int rpc_deal_parent(void)
+{
+    int len, handle, pid;
+    char pid_s[PID_STR_MAX_LEN];
+    int val = 0;
+
+    /* in systemctl mode, parent process need to write child pid */
+    if (socketpair(AF_UNIX, SOCK_STREAM, 0, g_fd) < 0) {
+        etmemd_log(ETMEMD_LOG_ERR, "Error initing pipefd\n");
+        return -1;
+    }
+
+    pid = fork();
+    if (pid != 0) {
+        if ((handle = open("/run/etmemd.pid", O_WRONLY | O_CREAT | O_TRUNC, S_IREAD | S_IWRITE)) == -1) {
+            etmemd_log(ETMEMD_LOG_ERR, "Error opening file\n");
+            exit(1);
+        }
+
+        if ((len = sprintf_s(pid_s, PID_STR_MAX_LEN, "%d", pid)) <= 0) {
+            etmemd_log(ETMEMD_LOG_ERR, "sprintf for pid failed\n");
+            exit(1);
+        }
+
+        if ((write(handle, pid_s, len)) != len) {
+            etmemd_log(ETMEMD_LOG_ERR, "Error writing to the file\n");
+            exit(1);
+        }
+
+        close(g_fd[1]);
+        if (read(g_fd[0], &val, sizeof(val)) <= 0) {
+            etmemd_log(ETMEMD_LOG_ERR, "Error reading to the file\n");
+            exit(1);
+        }
+
+        if (val == 1) {
+            exit(0);
+        }
+    }
+    return 0;
+}
+
+static int rpc_deal_child(void)
+{
+    int val = 1;
+    close(g_fd[0]);
+    if (write(g_fd[1], &val, sizeof(val)) <= 0) {
+        etmemd_log(ETMEMD_LOG_ERR, "Error writing pipe fd\n");
+        return -1;
+    }
+    close(g_fd[1]);
+    return 0;
+}
+
 int etmemd_rpc_server(void)
 {
+    /* in systemctl mode, parent process need to write child pid */
+    if (g_use_systemctl) {
+        if (rpc_deal_parent() != 0) {
+            etmemd_log(ETMEMD_LOG_ERR, "Error deal by parent process\n");
+            return -1;
+        }
+    }
     if (!etmemd_sock_name_set()) {
         etmemd_log(ETMEMD_LOG_ERR, "socket name of rpc must be provided\n");
         return -1;
@@ -661,6 +733,14 @@ int etmemd_rpc_server(void)
         return -1;
     }
 
+    /* in systemctl mode, child process need to notify parent to exit  */
+    if (g_use_systemctl) {
+        if (rpc_deal_child() != 0) {
+            etmemd_log(ETMEMD_LOG_ERR, "Error sending message to parent process\n");
+            return -1;
+        }
+    }
+
     while (!g_exit) {
         if (etmemd_rpc_accept(g_sock_fd) != 0) {
             etmemd_log(ETMEMD_LOG_ERR, "handle remote call failed once, error(%s)\n",
diff --git a/src/etmemd_src/etmemd_task.c b/src/etmemd_src/etmemd_task.c
index b948c63..01491f7 100644
--- a/src/etmemd_src/etmemd_task.c
+++ b/src/etmemd_src/etmemd_task.c
@@ -205,7 +205,7 @@ static int get_pid_from_type_name(char *val, char *pid)
     char *arg_pid[] = {"/usr/bin/pgrep", "-x", val, NULL};
     FILE *file = NULL;
     int ret = -1;
-    int pipefd[2]; /* used for pipefd[2] communication to obtain the task PID */
+    int pipefd[PIPE_FD_LEN]; /* used for pipefd[PIPE_FD_LEN] communication to obtain the task PID */
 
     if (pipe(pipefd) == -1) {
         return -1;
@@ -269,7 +269,7 @@ static int fill_task_child_pid(struct task *tk, char *pid)
     char *arg_pid[] = {"/usr/bin/pgrep", "-P", pid, NULL};
     FILE *file = NULL;
     int ret;
-    int pipefd[2]; /* used for pipefd[2] communication to obtain the task PID */
+    int pipefd[PIPE_FD_LEN]; /* used for pipefd[PIPE_FD_LEN] communication to obtain the task PID */
 
     if (pipe(pipefd) == -1) {
         return -1;
-- 
2.27.0