#include <stdio.h>

#include <stdlib.h>

#include <string.h>

typedef struct _Buffer {

  char *buff;

  int  room, used;

} Buffer;

void InitBuffer (Buffer *b);

void AppendToBuffer (Buffer *b, const char *str, int len);

void ReadFile (Buffer *buffer, FILE *input);

#define INIT_BUFFER_SIZE 10000

void

InitBuffer (Buffer *b)

{

  b->room = INIT_BUFFER_SIZE;

  b->used = 0;

  b->buff = (char *)malloc(INIT_BUFFER_SIZE*sizeof(char));

}

void

AppendToBuffer (Buffer *b, const char *str, int len)

{

  while (b->used + len > b->room) {

    b->buff = (char *)realloc(b->buff, 2*b->room*(sizeof(char)));

    b->room *= 2;

  }

  strncpy(b->buff + b->used, str, len);

  b->used += len;

}

void

ReadFile (Buffer *buffer, FILE *input)

{

  char       buf[BUFSIZ + 1];

  int        bytes;

  buffer->used = 0;

  while (!feof(input) && (bytes = fread(buf, 1, BUFSIZ, input)) > 0) {

    AppendToBuffer(buffer, buf, bytes);

  }

  AppendToBuffer(buffer, "", 1);

}

int

main(int argc, char *argv[])

{

  char filename[] = "xbug.c";

  FILE *input;

  Buffer buffer;

  InitBuffer(&buffer);

  if (!freopen (filename, "r", stdin))

    fprintf(stderr, "cannot open file\n");

  unsetenv ("LD_LIBRARY_PATH");

  if (!(input = popen("/bin/cat", "r")))

    fprintf(stderr, "cannot run \n");

  ReadFile(&buffer, input);

  pclose(input);

  return 0;

}