add interactive mode for /bin/sh entrypoint

src/container.c

@@ -39,12 +39,12 @@ int container_create(void *stuff)
     }
 
     // run container command
-    if (run_subprocess_async(cloneArgs->argv) != 0)
+    if (run_subprocess_async(cloneArgs->argc, cloneArgs->argv) != 0)
     {
         error_handler_container(c, "failed to execvp arguments");
     }
 
-    free(c); // free twice don't know why but maybe clone lost
+    free(c); // free twice don't know why but maybe clone lost c reference
     c = NULL;
 
     // we end container
@@ -75,7 +75,7 @@ pid_t run_container(container_t *c)
     {
         error_handler_container(c, "failed to run_container clone");
     }
-    // lets wait on our child process here before we, the parent, exits
+    // lets wait on our child process here before we, the parent, exit
     if (waitpid(pid, NULL, 0) == -1)
     {
         error_handler_container(c, "failed to wait pid %d", pid);

src/data.c

@@ -68,4 +68,43 @@ char *read_infinite_fd(int fd)
     return stdout_buffer;
 }
 
+/**
+ * Read stdin and write to file descriptor
+ */
+void write_infinite_fd(int fd)
+{
+    char *stdin_buffer = new_array(1024);
+    int x = 0;
+    printf("$ ");
+    fflush(stdout);
+
+    while ((x = read(STDIN_FILENO, stdin_buffer, sizeof(stdin_buffer))) > 0)
+    {
+        write(fd, stdin_buffer, sizeof(stdin_buffer));
+        init_array(stdin_buffer, sizeof(stdin_buffer));
+        printf("$ ");
+        fflush(stdout);
+    }
+    free(stdin_buffer);
+}
+
+/**
+ * Function use to filter char* array
+ * copy src char* into dst if function is true
+ * Return dst length
+ */
+int filter_char_array(int src_length, char **src, char **dst, char_predicate filter_func)
+{
+    int dst_size = 0;
+    for (int i = 0; i < src_length; i++)
+    {
+        if ((*filter_func)(src[i]))
+        {
+            dst[dst_size] = src[i];
+            dst_size++;
+        }
+    }
+    return dst_size;
+}
+
 #endif

src/main.c

@@ -12,6 +12,7 @@ int main(int argc, char *const argv[])
     }
 
     struct clone_args cloneArgs;
+    cloneArgs.argc = argc - 1;
     cloneArgs.argv = &argv[1];
     cloneArgs.hostname = "container-hostname";
 

src/prototype.h

@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include <stdbool.h>
 
 #include "./type.h"
 
@@ -19,15 +20,20 @@ void error(const char *sys_msg, ...);
 void last_error(const char *sys_msg, ...);
 
 // system.c
-int run_subprocess_async(char *const *argv);
+int run_subprocess_async(int argc, char *const *argv);
 int run_subprocess(char *const *argv);
 int pivot_root(char *mount_dir);
 int clean_pivot_root(char *a);
 void remount();
+bool is_interactive(char *str);
+bool is_not_interactive(char *str);
+bool contain_interactive(int argc, char *const *argv);
 
 // data.c
 char *new_array(size_t size);
 void init_array(char *arr, size_t size);
 char *read_infinite_fd(int fd);
+void write_infinite_fd(int fd);
+int filter_char_array(int src_length, char **src, char **dst, char_predicate filter_func);
 
 #endif

src/system.c

@@ -13,6 +13,7 @@
 #include <sys/syscall.h>
 #include <signal.h>
 #include <sys/stat.h>
+#include <stdbool.h>
 
 #include <sys/wait.h>
 #include <string.h>
@@ -111,13 +112,21 @@ int run_subprocess(char *const *argv)
 /**
  * Run external binary into new sub process
  */
-int run_subprocess_async(char *const *argv)
+int run_subprocess_async(int argc, char *const *argv)
 {
     pid_t pid;
+    bool run_interactive = contain_interactive(argc, argv);
+    // if container is running in interactive mode remove "-i" from argv
+    if (run_interactive)
+    {
+        char **dst_argv = (char **)malloc(sizeof(char *) * argc);
+        argc = filter_char_array(argc, (char **)argv, dst_argv, is_not_interactive);
+        argv = dst_argv;
+    }
 
-    // pipe to permit child => parent comunication
-    int pipefd[2];
-    pipe(pipefd);
+    // pipe to permit parent => child comunication
+    int pipe_parent_to_child_fd[2];
+    pipe(pipe_parent_to_child_fd);
 
     if ((pid = fork()) == -1)
     {
@@ -125,13 +134,10 @@ int run_subprocess_async(char *const *argv)
     }
     else if (pid == 0)
     {
-        close(pipefd[0]); // close reading end in the child
+        close(pipe_parent_to_child_fd[1]); // close writing end in the child
 
         printf("[CHILD] : running\n");
-        dup2(pipefd[1], 1); // send stdout to the pipe
-        dup2(pipefd[1], 2); // send stderr to the pipe
-
-        close(pipefd[1]); // this descriptor is no longer needed
+        dup2(pipe_parent_to_child_fd[0], STDIN_FILENO); // send pipe to the stdin
 
         errno = execvp(argv[0], argv);
         return errno;
@@ -140,20 +146,23 @@ int run_subprocess_async(char *const *argv)
     {
         int child_status;
 
-        close(pipefd[1]); // close the write end of the pipe in the parent
+        close(pipe_parent_to_child_fd[0]); // close the read end of the pipe in the parent
 
+        // if container is running in interactive mode
+        if (run_interactive)
+        {
+            // read stdin write infinity
+            write_infinite_fd(pipe_parent_to_child_fd[1]);
+        }
+
+        close(pipe_parent_to_child_fd[1]); // this descriptor is no longer needed
+
+        // wait child if long task is in progress
         waitpid(pid, &child_status, 0);
         if (WIFEXITED(child_status))
         {
-            char *stdout_buffer = read_infinite_fd(pipefd[0]);
-            printf("[PARENT] child stdout : \n%s\n", stdout_buffer);
-            free(stdout_buffer);
-
-            close(pipefd[0]); // close the descriptor is no longer needed
-
             int es = WEXITSTATUS(child_status);
             printf("[PARENT] Exit status was %d\n", es);
-
             return es;
         }
     }
@@ -161,4 +170,42 @@ int run_subprocess_async(char *const *argv)
     return EXIT_FAILURE;
 }
 
+/**
+ * Return true if char* str is equal to "-i"
+ */
+bool is_interactive(char *str)
+{
+    if (strcmp(str, "-i") == 0)
+    {
+        return true;
+    }
+    return false;
+}
+
+/**
+ * Return true if char* str is not equal to "-i"
+ * opposite of is_interactive
+ */
+bool is_not_interactive(char *str)
+{
+    return !is_interactive(str);
+}
+
+/**
+ * Return true if argv char* array contain "-i"
+ */
+bool contain_interactive(int argc, char *const *argv)
+{
+    bool res = false;
+    for (int i = 0; i < argc; i++)
+    {
+        if (is_interactive(argv[i]))
+        {
+            res = true;
+            break;
+        }
+    }
+    return res;
+}
+
 #endif

src/type.h

@@ -6,6 +6,7 @@
  */
 struct clone_args
 {
+    int argc;
     char *const *argv;
     const char *hostname;
 };
@@ -19,4 +20,6 @@ typedef struct container_t
     struct clone_args cloneArgs;
 } container_t;
 
+typedef bool (*char_predicate)(char *);
+
 #endif