1 files changed, 155 insertions, 0 deletions
diff --git a/userland/minibox/utilities/sh/sh.c b/userland/minibox/utilities/sh/sh.c
new file mode 100644
index 0000000..590e489
--- /dev/null
+++ b/userland/minibox/utilities/sh/sh.c
@@ -0,0 +1,155 @@
+#include "ast.h"
+#include "lexer.h"
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int execute_command(struct AST *ast, int input_fd);
+
+int execute_binary(struct AST *ast, int input_fd) {
+  char *program = ast->val.string;
+  struct AST *child = ast->children;
+  char *argv[100];
+  argv[0] = program;
+  int i = 1;
+  for (; child; i++, child = child->next) {
+    argv[i] = child->val.string;
+  }
+  argv[i] = NULL;
+
+  int in = input_fd;
+  int out = STDOUT_FILENO;
+  int slave_input = -1;
+
+  int file_out_fd;
+  if (ast->file_out) {
+    file_out_fd =
+        open(ast->file_out,
+             O_WRONLY | O_CREAT | ((ast->file_out_append) ? O_APPEND : O_TRUNC),
+             0666);
+  }
+
+  if (ast->pipe_rhs) {
+    int fds[2];
+    pipe(fds);
+    out = fds[1];
+    slave_input = fds[0];
+  }
+
+  int pid = fork();
+  if (0 == pid) {
+    if (slave_input >= 0)
+      close(slave_input);
+    dup2(in, STDIN_FILENO);
+    dup2(out, STDOUT_FILENO);
+    if (ast->file_out)
+      dup2(file_out_fd, ast->file_out_fd_to_use);
+
+    execvp(program, argv);
+    exit(1);
+  }
+  if (ast->file_out)
+    close(file_out_fd);
+
+  if (ast->pipe_rhs) {
+    if (out >= 0)
+      close(out);
+    return execute_command(ast->pipe_rhs, slave_input);
+  }
+  int rc;
+  // FIXME: Should use waitpid ... when my OS supports that
+  wait(&rc);
+  return rc;
+}
+
+int execute_command(struct AST *ast, int input_fd) {
+  char *program = ast->val.string;
+  if (0 == strcmp(program, "cd")) {
+    struct AST *child = ast->children;
+    char *directory;
+    if (!child)
+      directory = "~";
+    else
+      directory = child->val.string;
+    int rc = chdir(directory);
+    if (-1 == rc) {
+      perror("cd");
+      return 1;
+    }
+    return 0;
+  }
+  return execute_binary(ast, input_fd);
+}
+
+void execute_ast(struct AST *ast) {
+  int rc = -1;
+  for (; ast;) {
+    if (AST_COMMAND == ast->type) {
+      rc = execute_command(ast, STDIN_FILENO);
+    } else if (AST_CONDITIONAL_AND == ast->type) {
+      if (0 != rc) {
+        ast = ast->next;
+        if (!ast)
+          break;
+      }
+    } else if (AST_CONDITIONAL_NOT == ast->type) {
+      if (0 == rc) {
+        ast = ast->next;
+        if (!ast)
+          break;
+      }
+    }
+    ast = ast->next;
+  }
+}
+
+char *get_line(void) {
+  char *str = malloc(1024);
+  char *p = str;
+  int rc;
+  for (;;) {
+    if (0 == (rc = read(0, p, 1))) {
+      continue;
+    }
+    if (0 > rc) {
+      perror("read");
+      continue;
+    }
+    if (8 == *p) {
+      if (p == str)
+        continue;
+      putchar(*p);
+      p--;
+      continue;
+    }
+    putchar(*p);
+    if ('\n' == *p) {
+      break;
+    }
+    p++;
+  }
+  p++;
+  *p = '\0';
+  return str;
+}
+
+int sh_main(int argc, char **argv) {
+  (void)argc;
+  (void)argv;
+  for (;;) {
+    printf("/ : ");
+    char *line = get_line();
+    {
+      struct TOKEN *h = lex(line);
+      struct AST *ast_h = generate_ast(h);
+      execute_ast(ast_h);
+      free_tokens(h);
+      free_ast(ast_h);
+    }
+    free(line);
+  }
+  return 0;
+}