1 files changed, 159 insertions, 0 deletions
diff --git a/src/eval/eval_exe.cc b/src/eval/eval_exe.cc
new file mode 100644
index 0000000..534b878
--- /dev/null
+++ b/src/eval/eval_exe.cc
@@ -0,0 +1,159 @@
+#include "eval.h"
+
+#include <string>
+
+#include "error.h"
+#include "lang_analysis/lexer_class.h"
+#include "lang_analysis/ast.h"
+#include "lang_analysis/token.h"
+#include "lang_analysis/enum_type.h"
+#include "lang_analysis/symbol_property.h"
+#include "lang_analysis/parseline.h"
+#include "util/io.h"
+
+using namespace std;
+
+extern char **environ;
+
+namespace ov4
+{
+
+int eval_exe(const string &s, bool is_async)
+{
+    return eval_exe(s, is_async, nullptr, string::npos);
+}
+
+int eval_exe(const string &s, bool is_async, const T_lexer *lexer_instance, size_t i)
+{
+    loggerln("eval_exe: receive {}", s);
+
+    bool task_type_is_subshell = false;
+    const char *raw_input = nullptr;
+    char **argv = nullptr;
+    const char *unified_cmd_c = nullptr;
+    string unified_cmd, s_wrap_eliminated;
+
+    // subshell type
+    if (lexer_instance != nullptr)
+    {
+        task_type_is_subshell = true;
+        unified_cmd  = "SUBSHELL";
+        raw_input = unified_cmd.c_str();
+    } 
+    // command type
+    else
+    {
+        task_type_is_subshell = false;
+        s_wrap_eliminated = s.substr(0, s.find('\n')); // eliminate \n
+        raw_input = s_wrap_eliminated.c_str();
+        
+        // NB: remember to delete
+        argv = parseline(s);
+
+        if (argv == nullptr || argv[0] == nullptr) { operator delete(argv); return 0; }
+
+        if (exe_bultin_command(argv)) { operator delete(argv); return 0; }
+
+        unified_cmd = find_cmd(argv[0]);
+        unified_cmd_c = unified_cmd.c_str();
+    }
+
+    // block_io signals can stop shell
+    // when child is at foreground, parent shell is at background
+    sigprocmask(SIG_BLOCK, &block_io, nullptr);    
+
+    sigset_t prev;
+    block_all(&prev);
+
+    shell_pgid = getpgid(0);
+    pid_t pid = fork();
+    
+    if (pid == 0) // child
+    {
+        setpgid(0, 0);
+        if (!is_async) // foreground
+            tcsetpgrp(tty_fd, getpgrp());
+
+        sigprocmask(SIG_SETMASK, &prev, nullptr);
+
+        // program inside execve may use SIGTTIN/SIGTTOU
+        // so just restore in child
+        sigprocmask(SIG_UNBLOCK, &block_io, nullptr);
+
+        // subshell
+        if (task_type_is_subshell)
+        {
+            eval_tree_cd(i, *lexer_instance, true);
+            exit(0);
+        }
+
+        // normal command
+        execve(unified_cmd_c, argv, environ);
+
+        // execve: if success, never returns
+
+        cout << raw_input << flush;
+        switch (errno)
+        {
+            case ENOTDIR:
+                println(": A component of the path prefix is not a directory.");
+                _exit(errno);
+                break;
+            
+            case ENAMETOOLONG:
+                println(": A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters.");
+                _exit(errno);
+                break;
+            
+            case ENOENT:
+                println(": The new process file does not exist.");
+                _exit(errno);
+                break;
+
+            case EACCES:
+                println(": The new process file mode denies execute permission.");
+                _exit(errno);
+                break;
+
+            default:
+                println(": Error, code: {}", errno);
+                _exit(errno);
+        }
+    }
+
+    // parent
+
+    operator delete(argv);
+    argv = nullptr;
+
+    exit_required_pid = pid;
+
+    if (!is_async)  // foreground
+    {   
+        addjob(pid, FG, raw_input); 
+        sigset_t prev_with_sigchld_blocked = prev;
+        sigaddset(&prev_with_sigchld_blocked, SIGCHLD);
+        sigprocmask(SIG_SETMASK, &prev_with_sigchld_blocked, NULL);
+        waitfg(pid);
+        sigprocmask(SIG_SETMASK, &prev, NULL);
+
+        return exit_code;
+    }
+    else // background
+    {
+        addjob(pid, BG, raw_input);
+        sigprocmask(SIG_SETMASK, &prev, NULL);
+        cout << "[" << pid2jid(pid) << "] (" << pid << ") " << raw_input;
+
+        // POSIX:
+        // async command returns 0 immediately
+        // TODO: recurring async 
+        return 0;
+    }
+
+
+
+    return 0;
+}
+
+}
+\ No newline at end of file