From 11d95f0d941825ba183115cd24ab2ea2242ed805 Mon Sep 17 00:00:00 2001
From: nocjj <1250062498@qq.com>
Date: Mon, 2 Nov 2020 13:44:54 +0800
Subject: [PATCH 5/8] proc: del /prc/pid/comm read

The content obtained from comm file can also be obtianed from the stat file,
So there is no need to read comm file.

Signed-off-by: nocjj <1250062498@qq.com>
---
 src/domain.c | 16 ++++++++--------
 src/proc.c   | 36 +++++++++++++++---------------------
 2 files changed, 23 insertions(+), 29 deletions(-)

diff --git a/src/domain.c b/src/domain.c
index 05f85dd..7f9173d 100644
--- a/src/domain.c
+++ b/src/domain.c
@@ -190,8 +190,7 @@ static int get_child_pid(struct domain *dom)
         }
         dom->threads[i].type = ISTHREAD;
         dom->threads[i].ppid = dom->pid;
-        if (get_proc_stat(&(dom->threads[i])) < 0 ||
-            get_proc_comm(&(dom->threads[i])) < 0) {
+        if (get_proc_stat(&(dom->threads[i])) < 0) {
             continue;
         }
         if (strstr(dom->threads[i].vmname, "CPU") != NULL &&
@@ -213,12 +212,6 @@ static int set_domain(struct domain *dom, const char *name)
     char pid[PID_STRING_MAX];
     char *end = NULL;
 
-    if (len >= DOMAIN_NAME_MAX - 1) {
-        return -1;
-    }
-    strcpy(dom->vmname, name);
-    dom->vmname[len - strlen(".pid")] = '\0';
-
     if (snprintf(path, BUF_SIZE, "%s/%s", VAR_RUN_QEMU_PATH, name) < 0) {
         return -1;
     }
@@ -241,6 +234,13 @@ static int set_domain(struct domain *dom, const char *name)
     if (get_proc_stat(dom) < 0 || get_child_pid(dom) < 0) {
         return -1;
     }
+
+    if (len >= DOMAIN_NAME_MAX - 1) {
+        return -1;
+    }
+    strcpy(dom->vmname, name);
+    dom->vmname[len - strlen(".pid")] = '\0';
+
     return 1;
 }
 
diff --git a/src/proc.c b/src/proc.c
index 2200bf0..0263c67 100644
--- a/src/proc.c
+++ b/src/proc.c
@@ -70,10 +70,12 @@ int get_proc_stat(struct domain *dom)
 {
     char buf[BUF_SIZE];
     char path[STAT_PATH_SIZE];
-    char *tmp = NULL;
+    char *tmp1 = NULL;
+    char *tmp2 = NULL;
     char *p = NULL;
     char *p_next = NULL;
     int i = 0;
+    int len;
 
     if (dom->type == ISDOMAIN) {
         if (snprintf(path, STAT_PATH_SIZE, "/proc/%u/stat", dom->pid) < 0) {
@@ -89,11 +91,19 @@ int get_proc_stat(struct domain *dom)
         return -1;
     }
 
-    /* read from state item of "...) S ..." */
-    tmp = strrchr(buf, ')');
-    tmp = tmp + 2;
+    /* read comm from "pid (comm) S" */
+    tmp1 = strrchr(buf, '(') + 1;
+    tmp2 = strrchr(buf, ')');
+    len = tmp2 - tmp1;
+    if (len >= DOMAIN_NAME_MAX || len < 0) {
+        return -1;
+    }
+    strncpy(dom->vmname, tmp1, len);
+    dom->vmname[len] = '\0';
 
-    for (p = strtok_r(tmp, " \t\r\n", &p_next); p && i < stat_size;
+    /* read start from process state */
+    tmp2 = tmp2 + 2;
+    for (p = strtok_r(tmp2, " \t\r\n", &p_next); p && i < stat_size;
          p = strtok_r(NULL, " \t\r\n", &p_next)) {
         if (proc_stab[i].get_fun != NULL) {
             sscanf(p, proc_stab[i].format, (*proc_stab[i].get_fun)(dom));
@@ -111,19 +121,3 @@ void refresh_delta_stat(struct domain *new, struct domain *old)
         }
     }
 }
-
-int get_proc_comm(struct domain *dom)
-{
-    char path[STAT_PATH_SIZE];
-    int len;
-
-    if (snprintf(path, STAT_PATH_SIZE, "/proc/%u/comm", dom->pid) < 0) {
-        return -1;
-    }
-
-    len = read_file(dom->vmname, DOMAIN_NAME_MAX, path);
-    if (len > 1) {
-        dom->vmname[len - 1] = '\0';
-    }
-    return len;
-}
-- 
2.27.0