support generating random string with -n flag

Author: liberize

README.md

@@ -99,7 +99,7 @@ Usage: ./ssc [-u] [-s] [-r] [-e|-E|-M file] [-0] [-n name] [-d date] [-m msg] [-
                            linux only, works like AppImage. if a directory is specified, create squashfs from it
   -0, --fix-argv0          try to fix $0, may not work
                            if it doesn't work or causes problems, try -n flag or use $SSC_ARGV0 instead
-  -n, --ps-name            change script path in ps output
+  -n, --ps-name            change script path in ps output, may contain 'XXXXXX' which will be replaced with a random string
                            upon execution, create a symlink to real path and pass it to the interperter
   -d, --expire-date        expire date, for example, 11/30/2023
   -m, --expire-message     expire message, default to 'script has expired!'

README_zh_CN.md

@@ -97,7 +97,7 @@ ssc本身并不是一个编译器，比如cc，它会生成包含脚本代码的
                            仅适用于Linux，类似AppImage。如果指定的是目录，从这个目录创建squashfs文件
   -0, --fix-argv0          尝试修复$0，可能不起作用
                            如果不起作用或造成问题，请尝试使用-n选项或使用$SSC_ARGV0代替$0
-  -n, --ps-name            更改ps输出中的脚本路径
+  -n, --ps-name            更改ps输出中的脚本路径，可包含XXXXXX，运行时替换为随机字符串
                            在执行时，创建一个指向真实路径的符号链接并将这个链接传递给解释器
   -d, --expire-date        过期日期，例如 11/30/2023
   -m, --expire-message     过期提示，默认为 script has expired!

src/main.cpp

@@ -13,6 +13,7 @@
 #include <string>
 #include <iterator>
 #include <algorithm>
+#include <random>
 #include "obfuscate.h"
 #include "utils.h"
 #include "embed.h"
@@ -266,14 +267,24 @@ int main(int argc, char* argv[]) {
 #endif
 
 #ifdef PS_NAME
-    if (is_symlink(OBF(STR(PS_NAME)))) {
-        unlink(OBF(STR(PS_NAME)));
+    std::string link_name(OBF(STR(PS_NAME)));
+    pos = link_name.find("XXXXXX");
+    if (pos != std::string::npos) {
+        const char *chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+        std::mt19937 gen(std::random_device{}());
+        std::uniform_int_distribution<> dist(0, strlen(chars) - 1);
+        for (; pos < link_name.size() && link_name[pos] == 'X'; pos++) {
+            link_name[pos] = chars[dist(gen)];
+        }
+    }
+    if (is_symlink(link_name.c_str())) {
+        unlink(link_name.c_str());
     }
-    if (symlink(path.c_str(), OBF(STR(PS_NAME))) != 0) {
-        LOGE("failed to create symlink! path=" STR(PS_NAME) " err=`%s`", strerror(errno));
+    if (symlink(path.c_str(), link_name.c_str()) != 0) {
+        LOGE("failed to create symlink! path=%s err=`%s`", link_name.c_str(), strerror(errno));
         return 5;
     }
-    path = OBF(STR(PS_NAME));
+    path = std::move(link_name);
     cleaner.add(path);
 #endif