diff -uNr ruby-3.0.0/addr2line.c ruby-3.0.0.mod/addr2line.c
--- ruby-3.0.0/addr2line.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/addr2line.c	2021-02-09 17:44:23.586601868 +0200
@@ -545,7 +545,7 @@
 follow_debuglink(const char *debuglink, int num_traces, void **traces,
 		 obj_info_t **objp, line_info_t *lines, int offset)
 {
-    static const char global_debug_dir[] = "/usr/lib/debug";
+    static const char global_debug_dir[] = "@TERMUX_PREFIX@/lib/debug";
     const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
     char *p;
     obj_info_t *o1 = *objp, *o2;
@@ -577,7 +577,7 @@
 follow_debuglink_build_id(const char *build_id, size_t build_id_size, int num_traces, void **traces,
                           obj_info_t **objp, line_info_t *lines, int offset)
 {
-    static const char global_debug_dir[] = "/usr/lib/debug/.build-id/";
+    static const char global_debug_dir[] = "@TERMUX_PREFIX@/lib/debug/.build-id/";
     const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
     char *p;
     obj_info_t *o1 = *objp, *o2;
diff -uNr ruby-3.0.0/dln_find.c ruby-3.0.0.mod/dln_find.c
--- ruby-3.0.0/dln_find.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/dln_find.c	2021-02-09 17:35:46.039359196 +0200
@@ -72,10 +72,7 @@
 
     if (!path) {
 	path =
-	    "/usr/local/bin" PATH_SEP
-	    "/usr/ucb" PATH_SEP
-	    "/usr/bin" PATH_SEP
-	    "/bin" PATH_SEP
+        "@TERMUX_PREFIX@/bin" PATH_SEP
 	    ".";
     }
     buf = dln_find_1(fname, path, buf, size, 1 DLN_FIND_EXTRA_ARG);
diff -uNr ruby-3.0.0/ext/etc/etc.c ruby-3.0.0.mod/ext/etc/etc.c
--- ruby-3.0.0/ext/etc/etc.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/ext/etc/etc.c	2021-02-09 17:41:07.618382244 +0200
@@ -672,7 +672,7 @@
     if (!len) return Qnil;
     tmpdir = rb_w32_conv_from_wchar(path, rb_filesystem_encoding());
 #else
-    const char default_tmp[] = "/tmp";
+    const char default_tmp[] = "@TERMUX_PREFIX@/tmp";
     const char *tmpstr = default_tmp;
     size_t tmplen = strlen(default_tmp);
 # if defined _CS_DARWIN_USER_TEMP_DIR
diff -uNr ruby-3.0.0/ext/fiddle/libffi-3.2.1/src/closures.c ruby-3.0.0.mod/ext/fiddle/libffi-3.2.1/src/closures.c
--- ruby-3.0.0/ext/fiddle/libffi-3.2.1/src/closures.c	2014-11-08 14:47:24.000000000 +0200
+++ ruby-3.0.0.mod/ext/fiddle/libffi-3.2.1/src/closures.c	2021-02-09 17:40:07.564105731 +0200
@@ -391,8 +391,8 @@
   int repeat;
 } open_temp_exec_file_opts[] = {
   { open_temp_exec_file_env, "TMPDIR", 0 },
-  { open_temp_exec_file_dir, "/tmp", 0 },
-  { open_temp_exec_file_dir, "/var/tmp", 0 },
+  { open_temp_exec_file_dir, "@TERMUX_PREFIX@/tmp", 0 },
+  { open_temp_exec_file_dir, "@TERMUX_PREFIX@/var/tmp", 0 },
   { open_temp_exec_file_dir, "/dev/shm", 0 },
   { open_temp_exec_file_env, "HOME", 0 },
 #ifdef HAVE_MNTENT
diff -uNr ruby-3.0.0/ext/pty/pty.c ruby-3.0.0.mod/ext/pty/pty.c
--- ruby-3.0.0/ext/pty/pty.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/ext/pty/pty.c	2021-02-09 17:45:16.473977053 +0200
@@ -176,7 +176,7 @@
     char		errbuf[32];
 
     if (argc == 0) {
-	const char *shellname = "/bin/sh";
+	const char *shellname = "@TERMUX_PREFIX@/bin/sh";
 
 	if ((p = getenv("SHELL")) != NULL) {
 	    shellname = p;
diff -uNr ruby-3.0.0/hash.c ruby-3.0.0.mod/hash.c
--- ruby-3.0.0/hash.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/hash.c	2021-02-09 17:43:01.683876134 +0200
@@ -717,11 +717,11 @@
             else {
 #if 0
                 static int pid;
-                static char fname[256];
+                static char fname[sizeof("@TERMUX_PREFIX@/tmp")+256];
                 static FILE *fp;
 
                 if (pid != getpid()) {
-                    snprintf(fname, sizeof(fname), "/tmp/ruby-armiss.%d", pid = getpid());
+                    snprintf(fname, sizeof(fname), "@TERMUX_PREFIX@/tmp/ruby-armiss.%d", pid = getpid());
                     if ((fp = fopen(fname, "w")) == NULL) rb_bug("fopen");
                 }
 
diff -uNr ruby-3.0.0/lib/drb/gw.rb ruby-3.0.0.mod/lib/drb/gw.rb
--- ruby-3.0.0/lib/drb/gw.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/lib/drb/gw.rb	2021-02-09 17:35:46.039359196 +0200
@@ -99,8 +99,8 @@
 
 front = DRb::GW.new
 
-s1 = DRb::DRbServer.new('drbunix:/tmp/gw_b_a', front)
-s2 = DRb::DRbServer.new('drbunix:/tmp/gw_b_c', front)
+s1 = DRb::DRbServer.new('drbunix:@TERMUX_PREFIX@/tmp/gw_b_a', front)
+s2 = DRb::DRbServer.new('drbunix:@TERMUX_PREFIX@/tmp/gw_b_c', front)
 
 s1.thread.join
 s2.thread.join
@@ -131,9 +131,9 @@
 require 'foo'
 
 obj = Foo.new('a')
-DRb.start_service("drbunix:/tmp/gw_a", obj)
+DRb.start_service("drbunix:@TERMUX_PREFIX@/tmp/gw_a", obj)
 
-robj = DRbObject.new_with_uri('drbunix:/tmp/gw_b_a')
+robj = DRbObject.new_with_uri('drbunix:@TERMUX_PREFIX@/tmp/gw_b_a')
 robj[:a] = obj
 
 DRb.thread.join
@@ -146,9 +146,9 @@
 
 foo = Foo.new('c', nil)
 
-DRb.start_service("drbunix:/tmp/gw_c", nil)
+DRb.start_service("drbunix:@TERMUX_PREFIX@/tmp/gw_c", nil)
 
-robj = DRbObject.new_with_uri("drbunix:/tmp/gw_b_c")
+robj = DRbObject.new_with_uri("drbunix:@TERMUX_PREFIX@/tmp/gw_b_c")
 
 puts "c->b"
 a = robj[:a]
diff -uNr ruby-3.0.0/lib/mkmf.rb ruby-3.0.0.mod/lib/mkmf.rb
--- ruby-3.0.0/lib/mkmf.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/lib/mkmf.rb	2021-02-09 17:35:46.039359196 +0200
@@ -1580,7 +1580,7 @@
     if path ||= ENV['PATH']
       path = path.split(File::PATH_SEPARATOR)
     else
-      path = %w[/usr/local/bin /usr/ucb /usr/bin /bin]
+      path = "@TERMUX_PREFIX@/bin"
     end
     file = nil
     path.each do |dir|
diff -uNr ruby-3.0.0/lib/resolv.rb ruby-3.0.0.mod/lib/resolv.rb
--- ruby-3.0.0/lib/resolv.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/lib/resolv.rb	2021-02-09 17:35:46.043359300 +0200
@@ -173,7 +173,7 @@
       rescue LoadError
       end
     end
-    DefaultFileName ||= '/etc/hosts'
+    DefaultFileName ||= '@TERMUX_PREFIX@/etc/hosts'
 
     ##
     # Creates a new Resolv::Hosts, using +filename+ for its data source.
@@ -985,7 +985,7 @@
         return { :nameserver => nameserver, :search => search, :ndots => ndots }
       end
 
-      def Config.default_config_hash(filename="/etc/resolv.conf")
+      def Config.default_config_hash(filename="@TERMUX_PREFIX@/etc/resolv.conf")
         if File.exist? filename
           config_hash = Config.parse_resolv_conf(filename)
         else
diff -uNr ruby-3.0.0/mjit.c ruby-3.0.0.mod/mjit.c
--- ruby-3.0.0/mjit.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/mjit.c	2021-02-09 17:41:47.157406979 +0200
@@ -606,7 +606,7 @@
     RETURN_ENV("TMP");
     tmpdir = system_default_tmpdir();
     if (check_tmpdir(tmpdir)) return tmpdir;
-    return ruby_strdup("/tmp");
+    return ruby_strdup("@TERMUX_PREFIX@/tmp");
 # undef RETURN_ENV
 }
 
diff -uNr ruby-3.0.0/process.c ruby-3.0.0.mod/process.c
--- ruby-3.0.0/process.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/process.c	2021-02-09 17:49:30.716668413 +0200
@@ -1810,9 +1810,9 @@
     *argv = (char *)prog;
     *--argv = (char *)"sh";
     if (envp)
-        execve("/bin/sh", argv, envp); /* async-signal-safe */
+        execve("@TERMUX_PREFIX@/bin/sh", argv, envp); /* async-signal-safe */
     else
-        execv("/bin/sh", argv); /* async-signal-safe (since SUSv4) */
+        execv("@TERMUX_PREFIX@/bin/sh", argv); /* async-signal-safe (since SUSv4) */
 }
 
 #else
@@ -1880,9 +1880,9 @@
     }
 #else
     if (envp_str)
-        execle("/bin/sh", "sh", "-c", str, (char *)NULL, RB_IMEMO_TMPBUF_PTR(envp_str)); /* async-signal-safe */
+        execle("@TERMUX_PREFIX@/bin/sh", "sh", "-c", str, (char *)NULL, RB_IMEMO_TMPBUF_PTR(envp_str)); /* async-signal-safe */
     else
-        execl("/bin/sh", "sh", "-c", str, (char *)NULL); /* async-signal-safe (since SUSv4) */
+        execl("@TERMUX_PREFIX@/bin/sh", "sh", "-c", str, (char *)NULL); /* async-signal-safe (since SUSv4) */
 #endif	/* _WIN32 */
     return errno;
 }
diff -uNr ruby-3.1.0/ruby.c ruby-3.1.0.mod/ruby.c
--- ruby-3.1.0/ruby.c
+++ ruby-3.1.0.mod/ruby.c
@@ -359,7 +359,7 @@
         M("--mjit-warnings",      "", "Enable printing JIT warnings"),
         M("--mjit-debug",         "", "Enable JIT debugging (very slow), or add cflags if specified"),
         M("--mjit-wait",          "", "Wait until JIT compilation finishes every time (for testing)"),
-        M("--mjit-save-temps",    "", "Save JIT temporary files in $TMP or /tmp (for testing)"),
+        M("--mjit-save-temps",    "", "Save JIT temporary files in $TMP or @TERMUX_PREFIX@/tmp (for testing)"),
         M("--mjit-verbose=num",   "", "Print JIT logs of level num or less to stderr (default: 0)"),
         M("--mjit-max-cache=num", "", "Max number of methods to be JIT-ed in a cache (default: 100)"),
         M("--mjit-min-calls=num", "", "Number of calls to trigger JIT (for testing, default: 10000)"),
@@ -684,7 +684,7 @@
 	    RUBY_ARCH_PATH;
 	const ptrdiff_t libdir_len = (ptrdiff_t)sizeof(libdir)
 	    - rb_strlen_lit(RUBY_ARCH_PATH) - 1;
-	static const char bindir[] = "/bin";
+	static const char bindir[] = "@TERMUX_PREFIX@/bin";
 	const ptrdiff_t bindir_len = (ptrdiff_t)sizeof(bindir) - 1;
 
 	const char *p2 = NULL;
diff -uNr ruby-3.0.0/spec/bundler/commands/exec_spec.rb ruby-3.0.0.mod/spec/bundler/commands/exec_spec.rb
--- ruby-3.0.0/spec/bundler/commands/exec_spec.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/spec/bundler/commands/exec_spec.rb	2021-02-09 17:50:58.332721054 +0200
@@ -156,7 +156,7 @@
 
     install_gemfile 'gem "rack"'
     File.open(bundled_app("--verbose"), "w") do |f|
-      f.puts "#!/bin/sh"
+      f.puts "#!@TERMUX_PREFIX@/bin/sh"
       f.puts "echo foobar"
     end
     File.chmod(0o744, bundled_app("--verbose"))
diff -uNr ruby-3.0.0/spec/ruby/core/dir/shared/pwd.rb ruby-3.0.0.mod/spec/ruby/core/dir/shared/pwd.rb
--- ruby-3.0.0/spec/ruby/core/dir/shared/pwd.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/spec/ruby/core/dir/shared/pwd.rb	2021-02-09 17:50:07.720664849 +0200
@@ -14,7 +14,7 @@
     # The following uses inode rather than file names to account for
     # case insensitive file systems like default OS/X file systems
     platform_is_not :windows do
-      File.stat(pwd).ino.should == File.stat(`/bin/sh -c "pwd -P"`.chomp).ino
+      File.stat(pwd).ino.should == File.stat(`@TERMUX_PREFIX@/bin/sh -c "pwd -P"`.chomp).ino
     end
     platform_is :windows do
       File.stat(pwd).ino.should == File.stat(File.expand_path(`cd`.chomp)).ino
diff -uNr ruby-3.0.0/spec/ruby/core/process/exec_spec.rb ruby-3.0.0.mod/spec/ruby/core/process/exec_spec.rb
--- ruby-3.0.0/spec/ruby/core/process/exec_spec.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/spec/ruby/core/process/exec_spec.rb	2021-02-09 17:50:27.464678688 +0200
@@ -154,7 +154,7 @@
   describe "with a command array" do
     it "uses the first element as the command name and the second as the argv[0] value" do
       platform_is_not :windows do
-        ruby_exe('Process.exec(["/bin/sh", "argv_zero"], "-c", "echo $0")', escape: true).should == "argv_zero\n"
+        ruby_exe('Process.exec(["@TERMUX_PREFIX@/bin/sh", "argv_zero"], "-c", "echo $0")', escape: true).should == "argv_zero\n"
       end
       platform_is :windows do
         ruby_exe('Process.exec(["cmd.exe", "/C"], "/C", "echo", "argv_zero")', escape: true).should == "argv_zero\n"
@@ -163,7 +163,7 @@
 
     it "coerces the argument using to_ary" do
       platform_is_not :windows do
-        ruby_exe('o = Object.new; def o.to_ary; ["/bin/sh", "argv_zero"]; end; Process.exec(o, "-c", "echo $0")', escape: true).should == "argv_zero\n"
+        ruby_exe('o = Object.new; def o.to_ary; ["@TERMUX_PREFIX@/bin/sh", "argv_zero"]; end; Process.exec(o, "-c", "echo $0")', escape: true).should == "argv_zero\n"
       end
       platform_is :windows do
         ruby_exe('o = Object.new; def o.to_ary; ["cmd.exe", "/C"]; end; Process.exec(o, "/C", "echo", "argv_zero")', escape: true).should == "argv_zero\n"
diff -uNr ruby-3.0.0/spec/ruby/core/process/spawn_spec.rb ruby-3.0.0.mod/spec/ruby/core/process/spawn_spec.rb
--- ruby-3.0.0/spec/ruby/core/process/spawn_spec.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/spec/ruby/core/process/spawn_spec.rb	2021-02-09 17:50:41.692695143 +0200
@@ -133,7 +133,7 @@
   describe "with a command array" do
     it "uses the first element as the command name and the second as the argv[0] value" do
       platform_is_not :windows do
-        -> { Process.wait Process.spawn(["/bin/sh", "argv_zero"], "-c", "echo $0") }.should output_to_fd("argv_zero\n")
+        -> { Process.wait Process.spawn(["@TERMUX_PREFIX@/bin/sh", "argv_zero"], "-c", "echo $0") }.should output_to_fd("argv_zero\n")
       end
       platform_is :windows do
         -> { Process.wait Process.spawn(["cmd.exe", "/C"], "/C", "echo", "argv_zero") }.should output_to_fd("argv_zero\n")
@@ -156,7 +156,7 @@
     it "calls #to_ary to convert the argument to an Array" do
       o = mock("to_ary")
       platform_is_not :windows do
-        o.should_receive(:to_ary).and_return(["/bin/sh", "argv_zero"])
+        o.should_receive(:to_ary).and_return(["@TERMUX_PREFIX@/bin/sh", "argv_zero"])
         -> { Process.wait Process.spawn(o, "-c", "echo $0") }.should output_to_fd("argv_zero\n")
       end
       platform_is :windows do
diff -uNr ruby-3.0.0/st.c ruby-3.0.0.mod/st.c
--- ruby-3.0.0/st.c	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/st.c	2021-02-09 17:39:08.594113373 +0200
@@ -496,10 +496,10 @@
 static void
 stat_col(void)
 {
-    char fname[10+sizeof(long)*3];
+    char fname[sizeof("@TERMUX_PREFIX@/tmp/col")+sizeof(long)*3];
     FILE *f;
     if (!collision.total) return;
-    f = fopen((snprintf(fname, sizeof(fname), "/tmp/col%ld", (long)getpid()), fname), "w");
+    f = fopen((snprintf(fname, sizeof(fname), "@TERMUX_PREFIX@/tmp/col%ld", (long)getpid()), fname), "w");
     if (f == NULL)
         return;
     fprintf(f, "collision: %d / %d (%6.2f)\n", collision.all, collision.total,
diff -uNr ruby-3.0.0/tool/lib/webrick/config.rb ruby-3.0.0.mod/tool/lib/webrick/config.rb
--- ruby-3.0.0/tool/lib/webrick/config.rb	2020-12-25 05:33:01.000000000 +0200
+++ ruby-3.0.0.mod/tool/lib/webrick/config.rb	2021-02-09 17:35:46.043359300 +0200
@@ -35,7 +35,7 @@
       :Logger         => nil,   # default: WEBrick::Log.new
       :ServerSoftware => "WEBrick/#{WEBrick::VERSION} " +
                          "(Ruby/#{RUBY_VERSION}/#{RUBY_RELEASE_DATE})",
-      :TempDir        => ENV['TMPDIR']||ENV['TMP']||ENV['TEMP']||'/tmp',
+      :TempDir        => ENV['TMPDIR']||ENV['TMP']||ENV['TEMP']||'@TERMUX_PREFIX@/tmp',
       :DoNotListen    => false,
       :StartCallback  => nil,
       :StopCallback   => nil,