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401 lines
7.4 KiB
401 lines
7.4 KiB
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <string.h>
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#include <dirent.h>
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#include <signal.h>
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#include <errno.h>
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#include <fcntl.h>
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#include "yeeshell.h"
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/* record cmdline history */
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char *history[CMDLINE_HISTORY_MAX_QUANTITY];
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int cmdline_amount = 0;
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int main()
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{
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char *cmdline = NULL, *pwd = NULL;
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char *args[ARGS_MAX_QUANTITY];
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int status = 1;
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pwd = (char *)calloc(PATH_MAX_SIZE, sizeof(char));
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for (int i = 0; i < CMDLINE_HISTORY_MAX_QUANTITY; i++)
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{
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history[i] = (char *)calloc(CMDLINE_MAX_SIZE, sizeof(char));
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}
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/* execute the shell's read, parse and execution loop */
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do
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{
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if (!getcwd(pwd, PATH_MAX_SIZE))
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{
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printf("yeeshell: The current path cannot be obtained!\n");
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exit(0);
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}
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printf("[root@yeeshell %s]# ", pwd);
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cmdline = readline();
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strcpy(history[cmdline_amount++], cmdline);
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status = execute(cmdline, args);
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free(cmdline);
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} while (status);
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for (int i = 0; i < CMDLINE_HISTORY_MAX_QUANTITY; i++)
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{
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free(history[i]);
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}
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exit(EXIT_SUCCESS);
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}
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char *readline()
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{
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char *cmdline = NULL;
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ssize_t bufsize = 0;
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getline(&cmdline, &bufsize, stdin);
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return cmdline;
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}
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int parseline(char *cmdline, char **args)
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{
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static char array[CMDLINE_MAX_SIZE]; /* holds local copy of command line */
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char *buf = array; /* ptr that traverses command line */
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char *delim; /* points to first space delimiter */
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int argc; /* number of args */
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int bg; /* background job? */
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strcpy(buf, cmdline);
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buf[strlen(buf) - 1] = ' '; /* replace trailing '\n' with space */
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while (*buf && (*buf == ' ')) /* ignore leading spaces */
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{
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buf++;
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}
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/* Build the argv list */
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argc = 0;
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if (*buf == '\'')
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{
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buf++;
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delim = strchr(buf, '\'');
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}
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else
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{
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delim = strchr(buf, ' ');
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}
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while (delim)
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{
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args[argc++] = buf;
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*delim = '\0';
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buf = delim + 1;
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while (*buf && (*buf == ' ')) /* ignore spaces */
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{
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buf++;
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}
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if (*buf == '\'')
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{
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buf++;
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delim = strchr(buf, '\'');
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}
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else
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{
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delim = strchr(buf, ' ');
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}
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}
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args[argc] = NULL;
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if (argc == 0) /* ignore blank line */
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{
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return 1;
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}
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/* should the job run in the background? */
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if ((bg = (*args[argc - 1] == '&')) != 0)
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{
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args[--argc] = NULL;
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}
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return bg;
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}
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int check_redirect(char **args, char *redirect_filename, char **redirect_args)
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{
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int i = 0, j = 0, redirect_flag = REDIRECT_NO;
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while (args[i] != NULL)
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{
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if (!strcmp(args[i], ">"))
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{
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redirect_flag = REDIRECT_OUT;
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break;
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}
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else if (!strcmp(args[i], "<"))
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{
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redirect_flag = REDIRECT_IN;
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break;
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}
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i++;
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}
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if ((redirect_flag == 1) || (redirect_flag == 2))
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{
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strcpy(redirect_filename, args[i + 1]);
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for (j = 0; j < i; j++)
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{
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redirect_args[j] = args[j];
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}
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}
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return redirect_flag;
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}
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int check_pipe(char **args, char **pipe_arg_1, char **pipe_arg_2)
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{
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int pipe_flag = 0, i = 0, j = 0;
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while (args[i] != NULL)
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{
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if (!strcmp(args[i], "|"))
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{
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pipe_flag = 1;
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break;
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}
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pipe_arg_1[j++] = args[i++];
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}
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pipe_arg_1[j] = NULL;
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j = 0;
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i++;
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while (args[i] != NULL)
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{
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pipe_arg_2[j++] = args[i++];
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}
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pipe_arg_2[j] = NULL;
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return pipe_flag;
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}
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int execute(char *cmdline, char **args)
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{
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int bg = 0, i = 0, redirect_flag = 0, fd = 1, pipe_num = 0;
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pid_t pid;
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char *redirect_filename = NULL;
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char *redirect_args[ARGS_MAX_QUANTITY];
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char *pipe_arg_1[ARGS_MAX_QUANTITY];
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char *pipe_arg_2[ARGS_MAX_QUANTITY];
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redirect_filename = (char *)calloc(REDIRECT_FILENAME_MAX_SIZE, sizeof(char));
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memset(redirect_args, NULL, sizeof(redirect_args));
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bg = parseline(cmdline, args);
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redirect_flag = check_redirect(args, redirect_filename, redirect_args);
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pipe_num = check_pipe(args, pipe_arg_1, pipe_arg_2);
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if (args[0] == NULL)
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{
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return 1;
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}
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if (pipe_num == 0) /* no pipe */
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{
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if (!built_in(args)) /* built-in cmd? */
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{
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if ((pid = fork()) == 0) /* Child process */
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{
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if (redirect_flag == 1) /* redirect? */
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{
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fd = open(redirect_filename, O_CREAT | O_WRONLY | O_TRUNC, S_IRUSR | S_IWUSR | S_IXUSR);
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close(1);
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dup(fd);
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}
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else if (redirect_flag == 2)
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{
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fd = open(redirect_filename, O_RDONLY, S_IRUSR);
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close(0);
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dup(fd);
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}
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if ((redirect_flag == 1) || (redirect_flag == 2))
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{
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if (execvp(redirect_args[0], redirect_args) <= 0)
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{
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printf("%s: Command not found\n", args[0]);
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exit(0);
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}
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close(fd);
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}
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else
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{
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if (execvp(args[0], args) <= 0)
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{
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printf("%s: Command not found\n", args[0]);
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exit(0);
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}
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}
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}
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else /* parent process */
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{
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if (bg)
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{
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signal(SIGCHLD, SIG_IGN);
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}
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else
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{
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waitpid(pid, NULL, 0);
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}
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return 1;
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}
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}
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}
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else
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{
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int fds[2];
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pipe(fds);
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pid_t prog_1, prog_2;
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printf("%s %s %s %s", pipe_arg_1[0], pipe_arg_1[1], pipe_arg_1[2], pipe_arg_1[3]);
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if ((prog_1 = fork()) == 0) /* Child process 1 */
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{
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close(1);
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dup(fds[1]);
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close(fds[0]);
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close(fds[1]);
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if (execvp(pipe_arg_1[0], pipe_arg_1) <= 0)
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{
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printf("%s: Command not found\n", pipe_arg_1[0]);
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exit(0);
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}
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}
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if ((prog_2 = fork()) == 0) /* Child process 1 */
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{
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dup2(fds[0], 0);
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close(fds[0]);
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close(fds[1]);
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if (execvp(pipe_arg_2[0], pipe_arg_2) <= 0)
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{
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printf("%s: Command not found\n", pipe_arg_2[0]);
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exit(0);
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}
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}
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close(fds[0]);
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close(fds[1]);
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waitpid(prog_1, NULL, 0);
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waitpid(prog_2, NULL, 0);
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return 1;
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}
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return 0;
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}
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int built_in(char **args)
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{
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if (!strcmp(args[0], "exit"))
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{
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exit(0);
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}
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else if (!strcmp(args[0], "cd"))
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{
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return builtin_cd(args);
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}
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else if (!strcmp(args[0], "history"))
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{
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return builtin_history(args);
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}
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else if (!strcmp(args[0], "mytop"))
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{
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int flag = builtin_mytop();
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if (flag == -1)
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{
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printf("yeeshell: unable to get memory info.\n");
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}
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else if (flag == -2)
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{
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printf("yeeshell: unable to get CPU info.\n");
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}
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return flag;
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}
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else
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{
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return 0;
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}
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}
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int builtin_cd(char **args)
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{
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if (args[1] == NULL)
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{
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return 1;
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}
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else
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{
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if (chdir(args[1]) != 0)
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{
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perror("yeeshell");
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}
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return 1;
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}
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}
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int builtin_history(char **args)
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{
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int n = 0;
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if (args[1] == NULL)
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{
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n = cmdline_amount;
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}
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else
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{
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n = atoi(args[1]) < cmdline_amount ? atoi(args[1]) : cmdline_amount;
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}
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printf("ID\tCommandline\n");
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for (int i = 0; i < n; i++)
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{
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printf("%d\t%s\n", i + 1, history[i]);
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}
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return 1;
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}
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int builtin_mytop()
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{
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int memory_flag = 0, CPU_flag = 0;
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memory_flag = mytop_memory();
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CPU_flag = mytop_CPU();
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if (!memory_flag)
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{
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return -1;
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}
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else if (!CPU_flag)
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{
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return -2;
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}
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else
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{
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return 1;
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}
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}
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int mytop_memory()
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{
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FILE *fp = NULL;
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int pagesize;
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long total = 0, free = 0, cached = 0;
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if ((fp = fopen("/proc/meminfo", "r")) == NULL)
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{
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return 0;
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}
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fscanf(fp, "%u %lu %lu %lu", &pagesize, &total, &free, &cached);
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fclose(fp);
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printf("memmory(KBytes):\t%ld total\t%ld free\t%ld cached\n", (pagesize * total) / 1024, (pagesize * free) / 1024, (pagesize * cached) / 1024);
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return 1;
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}
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int mytop_CPU()
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{
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}
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