1 files changed, 137 insertions, 19 deletions

diff --git a/bcsh.c b/bcsh.c
index 6830671..08f7ac7 100644
--- a/bcsh.c
+++ b/bcsh.c
@@ -1,40 +1,161 @@
 #include "cmd.h"
 
 extern int yyparse();
+char hostname[100];
+char *username;
+char pwd[100];
 
 int main(int argc, char **argv) {
+    // 获取当前登陆的用户名、系统主机名、当前工作路径
+    gethostname(hostname, sizeof(hostname));
+    getcwd(pwd, sizeof(pwd));
+    username = getpwuid(getuid())->pw_name;
+    showPrompt();
     while (true) {
         yyparse();
     }
     return 0;
 }
 
+void showPrompt() {
+    printf("\033[01;32m%s@%s\033[00m:\033[33m%s\033[00m$ ", username, hostname,
+           pwd);
+    // 强制刷新缓冲区
+    fflush(stdout);
+}
+
 Command *newcmd() {
     Command *cmd = (Command *)malloc(sizeof(Command));
     cmd->argc = 0;
     cmd->args = NULL;
-    cmd->type = CMD_TYPE_NORMAL;
+    cmd->type = CMD_NORMAL;
     cmd->left = NULL;
     cmd->right = NULL;
+    for (int i = 0; i < 3; i++) {
+        cmd->redirectFile[i] = NULL;
+        cmd->redirectFD[i] = i;
+    }
+    cmd->background = false;
     return cmd;
 }
 
 int runcmd(Command *cmd) {
-    int i;
+    int status;
     if (cmd == NULL) {
         fprintf(stderr, "cmd is NULL\n");
-    } else if (cmd->type != CMD_TYPE_NORMAL) {
-        runcmd(cmd->left);
-        runcmd(cmd->right);
-        return 0;
+        return -1;
     }
-    printcmd(cmd);
-    if (!strcmp(cmd->args[0], "exit")) {
-        freecmd(cmd);
-        exit(0);
+
+    if (cmd->type == CMD_NORMAL) {
+        pid_t pid;
+        if (!strcmp(cmd->args[0], "exit")) {
+            printf("Good Bye, %s!\n", username);
+            exit(0);
+        } else if (!strcmp(cmd->args[0], "cd")) {
+            if (cmd->argc == 1) {
+                chdir(getenv("HOME"));
+            } else {
+                chdir(cmd->args[1]);
+            }
+            printf("\r");
+            getcwd(pwd, sizeof(pwd));
+        } else {
+            if ((pid = fork()) == 0) {
+                // consider the redirection now
+                // it's just a part of normal command
+                // but not in other types
+                for (int i = 0; i < 3; i++) {
+                    if (cmd->redirectFD[i] != i) {
+                        close(i);
+                        dup2(cmd->redirectFD[i], i);
+                    } else if (cmd->redirectFile[i] != NULL) {
+                        int fd =
+                            open(cmd->redirectFile[i], O_RDWR | O_CREAT, 0666);
+                        if (fd < 0) {
+                            fprintf(stderr, "open file %s failed\n",
+                                    cmd->redirectFile[i]);
+                            exit(-1);
+                        }
+                        close(i);
+                        dup2(fd, i);
+                        close(fd);
+                    }
+                }
+                if (cmd->background) {
+                    setpgid(0, 0);
+                    // no output, redirect 1 and 2 to /dev/null
+                    int fd = open("/dev/null", O_RDWR);
+                    dup2(fd, 1);
+                    dup2(fd, 2);
+                    close(fd);
+                }
+                exit(execvp(cmd->args[0], cmd->args));
+            } else {
+                if (!cmd->background) {
+                    waitpid(pid, &status, 0);
+                    if (!WIFEXITED(status)) {
+                        // when here, the child process exited abnormally
+                        fprintf(stderr, "Process %d exited with status %d\n",
+                                pid, WEXITSTATUS(status));
+                    }
+                }
+            }
+            // return the exit status of the child process
+            return WEXITSTATUS(status);
+        }
+    } else if (cmd->type == CMD_PIPE) {
+        // create a pipe file and gets two file descriptors
+        // fd[0] is the read end, while fd[1] the write end
+        int fd[2];
+        pid_t left, right;
+        pipe(fd);
+        if ((left = fork()) == 0) {
+            /*
+             * close the read end of the pipe, so that the child process
+             * can only write to it; then redirect the standard output
+             * to the write end of the pipe, and close the write end
+             * itself as a file descriptor.
+             */
+            close(fd[0]);
+            dup2(fd[1], 1);
+            close(fd[1]);
+            exit(runcmd(cmd->left));
+        }
+        if ((right = fork()) == 0) {
+            close(fd[1]);
+            dup2(fd[0], 0);
+            close(fd[0]);
+            exit(runcmd(cmd->right));
+        }
+        // close the pipe, because the parent process doesn't need it
+        // and wait for the two child processes to exit
+        close(fd[0]);
+        close(fd[1]);
+        waitpid(left, NULL, 0);
+        waitpid(right, NULL, 0);
+    } else if (cmd->type == CMD_AND) {
+        if (fork() == 0) {
+            exit(runcmd(cmd->left));
+        } else {
+            waitpid(-1, &status, 0);
+            if (WIFEXITED(status) && WEXITSTATUS(status) == 0 && fork() == 0) {
+                status = runcmd(cmd->right);
+            }
+            wait(NULL);
+        }
+    } else if (cmd->type == CMD_OR) {
+        if (fork() == 0) {
+            exit(runcmd(cmd->left));
+        } else {
+            waitpid(-1, &status, 0);
+            if (WIFEXITED(status) && WEXITSTATUS(status) != 0 && fork() == 0) {
+                status = runcmd(cmd->right);
+            }
+            wait(NULL);
+        }
     }
     freecmd(cmd);
-    return 0;
+    return status;
 }
 
 void freecmd(Command *cmd) {
@@ -52,13 +173,10 @@ void freecmd(Command *cmd) {
         free(cmd->args[i]);
     }
     free(cmd->args);
-    free(cmd);
-}
-
-void printcmd(Command *cmd) {
-    int i;
-    for (i = 0; i < cmd->argc; i++) {
-        printf("%s ", cmd->args[i]);
+    for (i = 0; i < 3; i++) {
+        if (cmd->redirectFile[i] != NULL) {
+            free(cmd->redirectFile[i]);
+        }
     }
-    printf("\n");
+    free(cmd);
 }
\ No newline at end of file