[Add] Redirecting and other fixes

gsc2001 · Oct 3, 2020 · 15d6a44 · 15d6a44
1 parent 6547a5c
commit 15d6a44
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Showing 9 changed files with 147 additions and 16 deletions.
diff --git a/Makefile b/Makefile
@@ -81,5 +81,8 @@ $(BUILD)/kjob.o: $(SRC)/kjob.c $(INC)/kjob.h $(INC)/errorHandler.h $(INC)/utils.
 $(BUILD)/piping.o: $(SRC)/piping.c $(INC)/piping.h $(INC)/errorHandler.h $(INC)/globals.h
 	$(COMMAND)  -o $(BUILD)/piping.o -c $(SRC)/piping.c
 
+$(BUILD)/redirecting.o: $(SRC)/redirecting.c $(INC)/redirecting.h $(INC)/errorHandler.h $(INC)/globals.h
+	$(COMMAND)  -o $(BUILD)/redirecting.o -c $(SRC)/redirecting.c
+
 clean: 
 	rm $(BUILD)/* gSH
diff --git a/include/globals.h b/include/globals.h
@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <dirent.h>
+#include <fcntl.h>
 
 #ifndef __GLOBAL_H
 #define __GLOBAL_H
@@ -38,6 +39,9 @@ typedef struct Command
     // for inp and out redirection
     char *inp;
     char *out;
+
+    // is out for appending ?
+    int append;
 } Command;
 
 // piped commands
@@ -64,4 +68,7 @@ typedef struct Process
 
 char *HOME;
 
+// global stdin and stdout save
+int stdoutSaveGlobal;
+
 #endif // __GLOBAL_H
diff --git a/include/redirecting.h b/include/redirecting.h
@@ -0,0 +1,11 @@
+/****************************************************
+author: gsc2001
+brief: redirection handling
+*****************************************************/
+#include "globals.h"
+#ifndef __REDIRECT_H
+#define __REDIRECT_H
+int stdinSave, stdoutSave, rfd, wfd;
+void redirectBegin(Command c);
+void redirectRestore();
+#endif // __REDIRECT_H
diff --git a/src/parse.c b/src/parse.c
@@ -9,6 +9,9 @@ Command parseCommand(char *command_raw)
 
     Command command;
     command.args = NULL;
+    command.inp = NULL;
+    command.out = NULL;
+    command.append = 0;
     command.bg = 0;
     command.cmd = strtok(command_, " ");
     if (command.cmd == NULL)
@@ -20,12 +23,35 @@ Command parseCommand(char *command_raw)
     arg = strtok(NULL, " ");
 
     // loop over args
+    int isInp = 0, isOut = 0;
     while (arg)
     {
-        if (!strlen(arg))
-            continue;
-
-        args_[command.argc++] = arg;
+        if (strlen(arg))
+        {
+            if (!strcmp(arg, "<") && isInp == 0)
+                isInp = 1;
+            else if (!strcmp(arg, ">") && isOut == 0)
+                isOut = 1;
+            else if (!strcmp(arg, ">>") && isOut == 0)
+            {
+                isOut = 1;
+                command.append = 1;
+            }
+            else if (isInp == 1)
+            {
+                isInp++;
+                command.inp = (char *)malloc(strlen(arg) + 1);
+                strcpy(command.inp, arg);
+            }
+            else if (isOut == 1)
+            {
+                isOut++;
+                command.out = (char *)malloc(strlen(arg) + 1);
+                strcpy(command.out, arg);
+            }
+            else
+                args_[command.argc++] = arg;
+        }
         arg = strtok(NULL, " ");
     }
     if (command.argc > 0 && !strcmp(args_[command.argc - 1], "&"))

diff --git a/src/piping.c b/src/piping.c
@@ -30,13 +30,13 @@ void execPiped(PipedCommands piped)
         {
             // inp from pipes[n-2][0] and out to STDOUT
             dup2(pipes[i - 1][0], STDIN_FILENO);
-
             dup2(stdoutSave, STDOUT_FILENO);
             execCommand(piped.commands[i]);
             handleSyscallint(close(pipes[i - 1][0]), "Closing pipe read end");
         }
         else
         {
+            // inp from pipes[i-1][0] and out to pipes[i][1]
             dup2(pipes[i - 1][0], STDIN_FILENO);
             dup2(pipes[i][1], STDOUT_FILENO);
             execCommand(piped.commands[i]);

diff --git a/src/redirecting.c b/src/redirecting.c
@@ -0,0 +1,47 @@
+#include "redirecting.h"
+#include "errorHandler.h"
+
+void redirectBegin(Command c)
+{
+    stdinSave = -1;
+    stdoutSave = -1;
+
+    if (c.inp)
+    {
+        rfd = handleSyscallint(open(c.inp, O_RDONLY), "Error opening inp file");
+        if (rfd >= 0)
+        {
+            stdinSave = dup(STDIN_FILENO);
+            dup2(rfd, STDIN_FILENO);
+        }
+    }
+    if (c.out)
+    {
+        if (c.append)
+            wfd = handleSyscallint(open(c.out, O_CREAT | O_WRONLY | O_APPEND, 0644), "Error opening output file");
+        else
+            wfd = handleSyscallint(open(c.out, O_CREAT | O_WRONLY | O_TRUNC, 0644), "Error opening output file");
+
+        if (wfd >= 0)
+        {
+            stdoutSave = dup(STDOUT_FILENO);
+            dup2(wfd, STDOUT_FILENO);
+        }
+    }
+}
+
+void redirectRestore()
+{
+    if (stdinSave >= 0)
+    {
+        dup2(stdinSave, STDIN_FILENO);
+        close(rfd);
+        close(stdinSave);
+    }
+    if (stdoutSave >= 0)
+    {
+        dup2(stdoutSave, STDOUT_FILENO);
+        close(wfd);
+        close(stdoutSave);
+    }
+}
diff --git a/src/shell.c b/src/shell.c
@@ -16,6 +16,7 @@
 #include "env.h"
 #include "kjob.h"
 #include "piping.h"
+#include "redirecting.h"
 
 void init()
 {
@@ -26,10 +27,13 @@ void init()
 
     // signal handlers
     signal(SIGCHLD, sigchldHandler);
-    // signal(SIGINT, sigintHandler);
+    signal(SIGINT, sigintHandler);
     signal(SIGTSTP, sigtstpHandler);
+
+    // saving stdout and stdin
+    stdoutSaveGlobal = dup(STDOUT_FILENO);
 }
-const int builtInN = 12;
+const int builtInN = 13;
 
 const char *builtInComs[] = {
     "pwd",
@@ -44,6 +48,7 @@ const char *builtInComs[] = {
     "setenv",
     "unsetenv",
     "kjob",
+    "exit",
 };
 
 // built in command functions
@@ -65,7 +70,7 @@ void (*builtInComExec[])(Command c) = {
 void execCommand(Command c)
 {
     int commandIndex = -1;
-
+    redirectBegin(c);
     for (int i = 0; i < builtInN; i++)
     {
         if (!strcmp(c.cmd, builtInComs[i]))
@@ -76,26 +81,35 @@ void execCommand(Command c)
     }
 
     if (commandIndex != -1)
+    {
+        if (commandIndex == 12)
+        {
+            // exit
+            byebye();
+            exit(0);
+        }
+
         builtInComExec[commandIndex](c);
+    }
     else
     {
         execSys(c);
     }
+    redirectRestore();
 }
 
 void repl()
 {
-    size_t inpsize;
-    char *inp = 0;
+    char *inp = NULL;
     size_t bufsize = 0;
 
     while (1)
     {
         char *prompt = get_prompt();
         printf("%s", prompt);
         fflush(stdout);
-        inpsize = getline(&inp, &bufsize, stdin);
-        if (inpsize < 0)
+        int len = getline(&inp, &bufsize, stdin);
+        if (len < 0)
             break;
         inp[strlen(inp) - 1] = '\0';
 
@@ -120,7 +134,8 @@ void repl()
                 for (int j = 0; j < piped.n; j++)
                 {
                     Command com = piped.commands[j];
-                    fprintf(stderr, "cmd=%s, argc=%d, backround=%d\n", com.cmd, com.argc, com.bg);
+                    fprintf(stderr, "cmd=%s, argc=%d, backround=%d, inp=%s, out=%s, append=%d\n",
+                            com.cmd, com.argc, com.bg, com.inp ? com.inp : "STDIN", com.out ? com.out : "STDOUT", com.append);
                     fprintf(stderr, "args->");
                     for (int k = 0; k < com.argc; k++)
                         fprintf(stderr, "%s,", com.args[k]);
@@ -141,5 +156,6 @@ void repl()
 
 void byebye()
 {
+    close(stdoutSaveGlobal);
     saveHistory();
 }
diff --git a/src/sysCommand.c b/src/sysCommand.c
@@ -15,6 +15,9 @@ void execSys(Command c)
     // fork
     pid_t forkReturn = handleSyscallint(fork(), "Error forking");
 
+    if (forkReturn < 0)
+        return;
+
     if (forkReturn == 0)
     {
         // child process
@@ -27,6 +30,9 @@ void execSys(Command c)
         int status;
         if (c.bg)
         {
+            // to print the pid to shell
+            dup2(stdoutSaveGlobal, STDOUT_FILENO);
+
             Process p;
             initProcess(&p, forkReturn, argv[0]);
             insertProcess(p);

diff --git a/src/utils.c b/src/utils.c
@@ -64,16 +64,31 @@ void initProcess(Process *loc, pid_t pid, char *name)
     strcpy(loc->name, name);
 }
 
+int checkEmpty(char *token)
+{
+    int l = strlen(token);
+    for (int i = 0; i < l; i++)
+    {
+        if (token[i] != ' ')
+            return 0;
+    }
+
+    return 1;
+}
+
 int splitString(char **strs, char *str, char *delim)
 {
     int n = 0;
     char *token = strtok(str, delim);
     while (token)
     {
-        strs[n] = (char *)malloc(strlen(token) + 1);
-        strcpy(strs[n++], token);
+        if (!checkEmpty(token))
+        {
+            strs[n] = (char *)malloc(strlen(token) + 1);
+            strcpy(strs[n++], token);
+        }
         token = strtok(NULL, delim);
     }
     free(token);
     return n;
-}
+}