diff --git a/Assignment-06/starter/dshlib.c b/Assignment-06/starter/dshlib.c
index b9115371cb17fa65d1c206f492ab4f5068dbea58..1216a77b0674d138679bafc129f89651e522c0b6 100644
--- a/Assignment-06/starter/dshlib.c
+++ b/Assignment-06/starter/dshlib.c
@@ -6,10 +6,11 @@
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
+#include <errno.h>
#include "dshlib.h"
-
+// Function to build a command buffer from a command line
int build_cmd_buff(char *cmd_line, cmd_buff_t *cmd_buff) {
if (cmd_line == NULL || cmd_buff == NULL) {
return ERR_CMD_OR_ARGS_TOO_BIG;
@@ -25,11 +26,11 @@ int build_cmd_buff(char *cmd_line, cmd_buff_t *cmd_buff) {
char *ptr = original_line;
char *arg_start = NULL;
- bool in_quotes = false;//For quotes
+ bool in_quotes = false; // For quotes
char quote_char = '\0';
while (*ptr != '\0') {
- if ((isspace((unsigned char)*ptr) && !in_quotes)) {
+ if ((isspace((unsigned char)*ptr) && !in_quotes) {
if (arg_start != NULL) {
*ptr = '\0';
cmd_buff->argv[cmd_buff->argc++] = arg_start;
@@ -59,18 +60,11 @@ int build_cmd_buff(char *cmd_line, cmd_buff_t *cmd_buff) {
cmd_buff->argv[cmd_buff->argc] = NULL;
- // Debugging output to verify parsing
- // printf("Parsed command:\n");
- // for (int i = 0; i < cmd_buff->argc; i++) {
- // printf(" argv[%d]: %s\n", i, cmd_buff->argv[i]);
- // }
-
-
-
return OK;
}
-char *trim_whitespace(char *str) { //Had to make a new function for readability
+// Function to trim whitespace from a string
+char *trim_whitespace(char *str) {
char *end;
while (isspace((unsigned char)*str)) str++;
@@ -82,15 +76,13 @@ char *trim_whitespace(char *str) { //Had to make a new function for readability
end = str + strlen(str) - 1;
while (end > str && isspace((unsigned char)*end)) end--;
- // new null terminator
+ // New null terminator
*(end + 1) = '\0';
return str;
}
-
-
-
+// Function to parse a pipeline of commands
int parse_pipeline(const char *cmd_line, command_list_t *clist) {
if (cmd_line == NULL || clist == NULL) {
return ERR_CMD_OR_ARGS_TOO_BIG;
@@ -100,7 +92,8 @@ int parse_pipeline(const char *cmd_line, command_list_t *clist) {
if (line_copy == NULL) {
return ERR_MEMORY;
}
- //Parsing using pipe.
+
+ // Parsing using pipe
clist->num = 0;
char *saveptr;
char *command = strtok_r(line_copy, "|", &saveptr);
@@ -126,22 +119,11 @@ int parse_pipeline(const char *cmd_line, command_list_t *clist) {
return OK;
}
-
-
+// Function to execute a pipeline of commands
int execute_pipeline(command_list_t *clist) {
int num_commands = clist->num;
int pipefd[2 * (num_commands - 1)];
pid_t pids[num_commands];
-
- // for (int i = 0; i < clist->num; i++) {
- // printf("Command %d:\n", i);
- // for (int j = 0; clist->commands[i].argv[j] != NULL; j++) {
- // printf(" argv[%d]: %s\n", j, clist->commands[i].argv[j]);
- // }
- // }
-
-
-
for (int i = 0; i < num_commands - 1; i++) {
if (pipe(pipefd + 2 * i) == -1) {
@@ -159,7 +141,7 @@ int execute_pipeline(command_list_t *clist) {
}
if (pids[i] == 0) { // Child process
- // if not first moves input
+ // Redirect input if not the first command
if (i > 0) {
if (dup2(pipefd[2 * (i - 1)], STDIN_FILENO) == -1) {
perror("dup2 stdin");
@@ -175,7 +157,7 @@ int execute_pipeline(command_list_t *clist) {
}
}
- // Close all pipe file descriptors. Very important stuff
+ // Close all pipe file descriptors
for (int j = 0; j < 2 * (num_commands - 1); j++) {
close(pipefd[j]);
}
@@ -187,12 +169,12 @@ int execute_pipeline(command_list_t *clist) {
}
}
- // Closes all pipe
+ // Close all pipe file descriptors in the parent
for (int i = 0; i < 2 * (num_commands - 1); i++) {
close(pipefd[i]);
}
- // waitpid so everyhting is smooth
+ // Wait for all child processes to finish
for (int i = 0; i < num_commands; i++) {
int status;
waitpid(pids[i], &status, 0);
@@ -206,137 +188,90 @@ int execute_pipeline(command_list_t *clist) {
return OK;
}
-static void start_server() {
- int listen_socket;
- int ret;
-
-}
-
-/****
- **** FOR REMOTE SHELL USE YOUR SOLUTION FROM SHELL PART 3 HERE
- **** THE MAIN FUNCTION CALLS THIS ONE AS ITS ENTRY POINT TO
- **** EXECUTE THE SHELL LOCALLY
- ****
- */
-
-/*
- * Implement your exec_local_cmd_loop function by building a loop that prompts the
- * user for input. Use the SH_PROMPT constant from dshlib.h and then
- * use fgets to accept user input.
- *
- * while(1){
- * printf("%s", SH_PROMPT);
- * if (fgets(cmd_buff, ARG_MAX, stdin) == NULL){
- * printf("\n");
- * break;
- * }
- * //remove the trailing \n from cmd_buff
- * cmd_buff[strcspn(cmd_buff,"\n")] = '\0';
- *
- * //IMPLEMENT THE REST OF THE REQUIREMENTS
- * }
- *
- * Also, use the constants in the dshlib.h in this code.
- * SH_CMD_MAX maximum buffer size for user input
- * EXIT_CMD constant that terminates the dsh program
- * SH_PROMPT the shell prompt
- * OK the command was parsed properly
- * WARN_NO_CMDS the user command was empty
- * ERR_TOO_MANY_COMMANDS too many pipes used
- * ERR_MEMORY dynamic memory management failure
- *
- * errors returned
- * OK No error
- * ERR_MEMORY Dynamic memory management failure
- * WARN_NO_CMDS No commands parsed
- * ERR_TOO_MANY_COMMANDS too many pipes used
- *
- * console messages
- * CMD_WARN_NO_CMD print on WARN_NO_CMDS
- * CMD_ERR_PIPE_LIMIT print on ERR_TOO_MANY_COMMANDS
- * CMD_ERR_EXECUTE print on execution failure of external command
- *
- * Standard Library Functions You Might Want To Consider Using (assignment 1+)
- * malloc(), free(), strlen(), fgets(), strcspn(), printf()
- *
- * Standard Library Functions You Might Want To Consider Using (assignment 2+)
- * fork(), execvp(), exit(), chdir()
- */
-
- int exec_remote_cmd_loop(char *address, int port) {
- char cmd_buff[RDSH_COMM_BUFF_SZ];
- char rsp_buff[RDSH_COMM_BUFF_SZ];
- int cli_socket;
- ssize_t recv_bytes;
- int is_eof;
-
- // Connect to the server
- cli_socket = start_client(address, port);
- if (cli_socket < 0) {
- perror("start client");
- return client_cleanup(cli_socket, NULL, NULL, ERR_RDSH_CLIENT);
- }
+// Main loop for executing local commands
+int exec_local_cmd_loop() {
+ char cmd_buff[SH_CMD_MAX];
+ int rc = OK;
while (1) {
- printf("rsh> ");
- if (!fgets(cmd_buff, RDSH_COMM_BUFF_SZ, stdin)) {
- break; // Exit on input error or EOF
+ printf("%s", SH_PROMPT);
+
+ if (fgets(cmd_buff, SH_CMD_MAX, stdin) == NULL) {
+ printf("\n");
+ break;
}
- // Remove the newline character from the command
- size_t cmd_len = strlen(cmd_buff);
- if (cmd_len > 0 && cmd_buff[cmd_len - 1] == '\n') {
- cmd_buff[cmd_len - 1] = '\0';
+ cmd_buff[strcspn(cmd_buff, "\n")] = '\0';
+
+ if (strlen(cmd_buff) == 0) {
+ printf("%s\n", CMD_WARN_NO_CMD);
+ rc = WARN_NO_CMDS;
+ continue;
}
- // Handle local commands (e.g., cd, exit)
- if (strncmp(cmd_buff, "cd", 2) == 0) {
- // Handle cd locally
+ if (strstr(cmd_buff, "|") != NULL) {
+ command_list_t cmd_list;
+ if (parse_pipeline(cmd_buff, &cmd_list) != OK) {
+ fprintf(stderr, "%s\n", CMD_ERR_PIPE_LIMIT);
+ rc = ERR_TOO_MANY_COMMANDS;
+ continue;
+ }
+
+ rc = execute_pipeline(&cmd_list);
+
+ // Free memory for each command's buffer
+ for (int i = 0; i < cmd_list.num; i++) {
+ free(cmd_list.commands[i]._cmd_buffer);
+ }
+ } else {
cmd_buff_t cmd;
if (build_cmd_buff(cmd_buff, &cmd) != OK) {
fprintf(stderr, "%s\n", CMD_ERR_PIPE_LIMIT);
+ rc = ERR_MEMORY;
continue;
}
- if (cmd.argc == 1) {
- chdir(getenv("HOME"));
- } else if (cmd.argc == 2) {
- if (chdir(cmd.argv[1]) != 0) {
- perror("cd");
+
+ if (strcmp(cmd.argv[0], EXIT_CMD) == 0) {
+ free(cmd._cmd_buffer);
+ break;
+ }
+
+ if (strcmp(cmd.argv[0], "cd") == 0) {
+ if (cmd.argc == 1) {
+ chdir(getenv("HOME"));
+ } else if (cmd.argc == 2) {
+ if (chdir(cmd.argv[1]) != 0) {
+ perror("cd");
+ }
+ } else {
+ fprintf(stderr, "%s\n", CMD_ERR_PIPE_LIMIT);
}
- } else {
- fprintf(stderr, "%s\n", CMD_ERR_PIPE_LIMIT);
+ free(cmd._cmd_buffer);
+ continue;
}
- free(cmd._cmd_buffer);
- continue;
- } else if (strncmp(cmd_buff, "exit", 4) == 0) {
- break; // Exit the remote shell
- }
- // Send the command to the server
- ssize_t sent_bytes = send(cli_socket, cmd_buff, strlen(cmd_buff), 0);
- if (sent_bytes < 0) {
- perror("send");
- return client_cleanup(cli_socket, NULL, NULL, ERR_RDSH_COMMUNICATION);
- }
+ pid_t pid = fork();
+ if (pid < 0) {
+ perror("fork failed");
+ rc = ERR_MEMORY;
+ } else if (pid == 0) {
+ execvp(cmd.argv[0], cmd.argv);
+ perror("execvp failed");
+ exit(EXIT_FAILURE);
+ } else {
+ int status;
+ wait(&status);
- // Receive the server's response
- is_eof = 0;
- while ((recv_bytes = recv(cli_socket, rsp_buff, RDSH_COMM_BUFF_SZ, 0)) > 0) {
- printf("%.*s", (int)recv_bytes, rsp_buff);
- if (rsp_buff[recv_bytes - 1] == RDSH_EOF_CHAR) {
- is_eof = 1;
- break;
+ if (WIFEXITED(status)) {
+ if (WEXITSTATUS(status) != 0) {
+ fprintf(stderr, "Command failed with exit code %d\n", WEXITSTATUS(status));
+ }
+ }
}
- }
- if (recv_bytes < 0) {
- perror("recv");
- return client_cleanup(cli_socket, NULL, NULL, ERR_RDSH_COMMUNICATION);
- } else if (recv_bytes == 0) {
- printf("Server closed the connection\n");
- break;
+ free(cmd._cmd_buffer);
}
}
- return client_cleanup(cli_socket, NULL, NULL, OK);
-}
+ return rc;
+}
\ No newline at end of file