diff --git a/cap.c b/cap.c
index 9d83bbc..1e09431 100644
--- a/cap.c
+++ b/cap.c
@@ -344,10 +344,11 @@ int main(int argc, char **argv)
         snprintf(RULE_NAME, BUFFER, "root%d", RULE_NAME_NUMBER);
 
         if (create_ipset(RULE_NAME) != 0) {
-            fprintf(stderr, "创建 IPSet %s 失败\n", RULE_NAME);
+            _printf("创建 IPSet %s 失败\n", RULE_NAME);
         }
-        while (1) {
 
+        while (1)
+        {
             _printf("子进程当前 Ipset Rule 名 %s\n", RULE_NAME);
 
             count = get_ip_count_in_ipset(RULE_NAME);
diff --git a/cap.o b/cap.o
index 10ea2f4..01d3e93 100644
Binary files a/cap.o and b/cap.o differ
diff --git a/common.c b/common.c
index b336329..043a308 100644
--- a/common.c
+++ b/common.c
@@ -1,21 +1,15 @@
 #include "common.h"
 
 // 计算字符串长度
-int _strlen(char *str)
-{
-    char *_p = NULL;
-
+int _strlen(const char *str) {
     if (str == NULL)
         return 0;
 
-    _p = strchr(str, '\0');
-
-    if (_p == NULL)
-        return 0;
-
+    const char *_p = strchr(str, '\0');
     return _p - str;
 }
 
+
 // 自定义 printf 函数
 void _printf(const char *format, ...)
 {
@@ -86,7 +80,7 @@ int whitelist(char *client_ip, char (*whitelist_ip)[WHITELIST_IP_NUM])
             break;
         }
 
-        // 对比client_ip的前缀是否与白名单中的IP段匹配
+        // 对比 client_ip 的前缀是否与白名单中的IP段匹配
         if (strncmp(client_ip, whitelist_ip[i], strlen(whitelist_ip[i])) == 0) {
             return 1;  // 匹配成功
         }
@@ -102,12 +96,12 @@ int isregion(char *str, char (*region_list)[WHITELIST_IP_NUM])
     char *p;
 
     for (i = 0; i < WHITELIST_IP_NUM; i++) {
-        // 如果region_list[i]为空字符串，跳出循环
+        // 如果 region_list[i] 为空字符串，跳出循环
         if (region_list[i][0] == '\0') {
             break;
         }
 
-        // 在str中查找region_list[i]
+        // 在str中查找 region_list[i]
         p = strstr(str, region_list[i]);
         if (p != NULL) {
             return 1; // 匹配成功，返回1
@@ -128,19 +122,23 @@ int8_t _copy_new_mem(char *src, int src_len, char **dest)
     return 0;
 }
 
-char *_time()
-{
-    char temp[BUFFER];
-    char *wday[] = { "0", "1", "2", "3", "4", "5", "6" };
-    time_t t;
-    struct tm *p;
-    time(&t);
-    p = localtime(&t);          // 取得当地时间
+// 返回的时间字符串存储在静态缓冲区中
+char *_time() {
+    static char temp[BUFFER];
+    const char *wday[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
+    time_t t = time(NULL);
+    struct tm *p = localtime(&t);
 
-    memset(temp, 0, BUFFER);
-    snprintf(temp, BUFFER, "[%d/%02d/%02d %s %02d:%02d:%02d] ", (1900 + p->tm_year), (1 + p->tm_mon), p->tm_mday, wday[p->tm_wday], p->tm_hour, p->tm_min, p->tm_sec);
+    if (!p) {
+        perror("localtime failed");
+        return NULL;
+    }
 
-    return strdup(temp);
+    snprintf(temp, sizeof(temp), "[%d/%02d/%02d %s %02d:%02d:%02d]", 
+             1900 + p->tm_year, 1 + p->tm_mon, p->tm_mday, 
+             wday[p->tm_wday], p->tm_hour, p->tm_min, p->tm_sec);
+
+    return temp; // 返回静态缓冲区地址
 }
 
 int is_valid_ip(const char *ip)
@@ -152,22 +150,73 @@ int is_valid_ip(const char *ip)
     return result != 0;
 }
 
-int _nice(int increment)
-{
+int _nice(int increment) {
+    // 获取当前优先级
     int oldprio = getpriority(PRIO_PROCESS, getpid());
-    printf("%d\n", oldprio);
+    if (oldprio == -1 && errno != 0) {
+        perror("getpriority failed");
+        return -1;
+    }
 
-    return setpriority(PRIO_PROCESS, getpid(), oldprio + increment);
+    printf("Current priority: %d\n", oldprio);
+
+    // 检查是否溢出
+    if ((increment > 0 && oldprio > INT_MAX - increment) ||
+        (increment < 0 && oldprio < INT_MIN - increment)) {
+        fprintf(stderr, "Priority overflow error\n");
+        return -1;
+    }
+
+    // 计算新的优先级
+    int newprio = oldprio + increment;
+
+    // 检查新的优先级是否在有效范围内
+    if (newprio < PRIO_MIN || newprio > PRIO_MAX) {
+        fprintf(stderr, "New priority out of range: %d (valid range is %d to %d)\n", newprio, PRIO_MIN, PRIO_MAX);
+        return -1;
+    }
+
+    // 设置新的优先级
+    if (setpriority(PRIO_PROCESS, getpid(), newprio) == -1) {
+        perror("setpriority failed");
+        return -1;
+    }
+
+    printf("New priority: %d\n", newprio);
+    return 0;
 }
 
 // 判断命令是否存在
-int _command_exists(const char *command)
-{
-    char buffer[BUFFER];
-    snprintf(buffer, sizeof(buffer), "%s > /dev/null 2>&1", command);
-    int status = system(buffer);
+int command_exists(const char *command) {
+    const char *path_env = getenv("PATH");
+    if (!path_env) {
+        return 0;  // 如果 PATH 不存在，返回不存在
+    }
 
-    return (status == 0);
+    char filepath[1024];  // 缓冲区大小
+    const char *dir = path_env;
+
+    while (dir && *dir) {
+        // 查找 PATH 中的下一个目录
+        const char *end = strchr(dir, ':');
+        size_t len = end ? (size_t)(end - dir) : strlen(dir);
+
+        // 构建路径并检查长度
+        if (snprintf(filepath, sizeof(filepath), "%.*s/%s", (int)len, dir, command) >= (int)sizeof(filepath)) {
+            return 0;  // 缓冲区溢出，返回不存在
+        }
+
+        // 检查文件是否存在且可执行
+        if (access(filepath, X_OK) == 0) {
+            puts(filepath);
+            return 1;  // 命令存在
+        }
+
+        // 更新 dir 指针
+        dir = end ? end + 1 : NULL;
+    }
+
+    return 0;  // 命令不存在
 }
 
 // 定义一个函数，执行命令并返回输出
diff --git a/common.h b/common.h
index d77bfbe..338e5d2 100644
--- a/common.h
+++ b/common.h
@@ -17,6 +17,7 @@
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <sys/utsname.h>
+#include <limits.h>
 
 #include <sys/resource.h>
 #include <signal.h>
@@ -28,7 +29,7 @@
 
 
 extern char *_time();
-extern int _strlen(char *str);
+extern int _strlen(const char *str);
 extern void _printf(const char *format, ...);
 extern int _nice(int increment);
 
diff --git a/common.o b/common.o
index 1ae8024..fe67c2c 100644
Binary files a/common.o and b/common.o differ
diff --git a/denyip b/denyip
index 072267f..5a97a67 100644
Binary files a/denyip and b/denyip differ