#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <locale.h>

#define MAP_SIZE 20
#define PATH_SIZE 64
#define BUFFER_SIZE 9600

static int read_buffer( char *buffer, unsigned size,
                        const char *file, char sep )
{
  int file_desc;
  unsigned total_bytes = 0;

  file_desc = open(file, O_RDONLY);
  if(file_desc == -1)
    return 0;

  for(;;)
  {
    ssize_t number_bytes = read( file_desc,
                                 buffer + total_bytes,
                                 size - total_bytes );
    if(number_bytes == -1)
    {
      if(errno==EINTR)
        continue;
      break;
    }

    total_bytes += number_bytes;
    if(total_bytes == size)
    {
      --total_bytes;
      break;
    }

    if(number_bytes==0)
      break;  // EOF
  }

  close(file_desc);

  if(total_bytes)
  {
    int i=total_bytes;

    while(i--)
      if(buffer[i]=='\n' || buffer[i]=='\0')
        buffer[i]=sep;

    if(buffer[total_bytes-1]==' ')
      buffer[total_bytes-1]='\0';
  }

  buffer[total_bytes] = '\0';
  return total_bytes;
}

static void total_smaps(unsigned proc_id, const char *file, const char *cmdline)
{
  FILE *file_pointer;
  char buffer[BUFFER_SIZE];

  unsigned long long total_private_dirty = 0ull;
  unsigned long long total_private_clean = 0ull;
  unsigned long long total_shared_dirty = 0ull;
  unsigned long long total_shared_clean = 0ull;
  unsigned long long smap_value;
  char smap_key[MAP_SIZE];

  if ((file_pointer = fopen(file, "r")) == NULL)
    error(EXIT_FAILURE, errno, "%s", file);

  while (fgets(buffer, sizeof(buffer), file_pointer))
  {
    if (buffer[0] >= 'A' && buffer[0] <= 'Z')
    {
      if (sscanf(buffer, "%20[^:]: %llu", smap_key, &smap_value) == 2)
      {
        if (strncmp("Shared_Dirty", smap_key, 12) == 0)
        {
          total_shared_dirty += smap_value;
          continue;
        }
        if (strncmp("Shared_Clean", smap_key, 12) == 0)
        {
          total_shared_clean += smap_value;
          continue;
        }
        if (strncmp("Private_Dirty", smap_key, 13) == 0)
        {
          total_private_dirty += smap_value;
          continue;
        }
        if (strncmp("Private_Clean", smap_key, 13) == 0)
        {
          total_private_clean += smap_value;
          continue;
        }
      }
    }
  }

  if ( errno )
    error(EXIT_FAILURE, errno, "%s\n", cmdline);

  printf("%s\n", cmdline);
  printf("Process ID    :%20d\n", proc_id);
  printf("--------------------------------------\n");
  printf("Shared Clean  :%20lld kB\n", total_shared_clean);
  printf("Shared Dirty  :%20lld kB\n", total_shared_dirty);
  printf("Private Clean :%20lld kB\n", total_private_clean);
  printf("Private Dirty :%20lld kB\n", total_private_dirty);
  printf("--------------------------------------\n");
  printf("Shared        :%20lld kB\n", total_shared_clean + total_shared_dirty);
  printf("Private       :%20lld kB\n\n", total_private_clean + total_private_dirty);
}

int main(int argc, char **argv)
{
  DIR *root_proc;
  struct dirent *dir_proc;

  unsigned pid_proc;
  char path_proc[PATH_SIZE];
  char cmdline[BUFFER_SIZE];

  setlocale (LC_ALL, "");
  getopt(argc, argv, "");

  if (argc != 2)
    error(EXIT_FAILURE, EINVAL, "incorrect arguments");

  root_proc = opendir("/proc");
  if (!root_proc)
    error(EXIT_FAILURE, errno, "%s", "/proc");

  while ( ( dir_proc = readdir(root_proc) ) )
  {
    if ( !dir_proc && !dir_proc->d_name[0] )
      error(EXIT_FAILURE, ENOTDIR, "bad dir");

    if ( *dir_proc->d_name > '0' && *dir_proc->d_name <= '9' )
    {
      pid_proc = strtoul(dir_proc->d_name, NULL, 10);
      snprintf(path_proc, sizeof(path_proc), "/proc/%s/%s", dir_proc->d_name, "cmdline");
      if (read_buffer(cmdline, sizeof(cmdline), path_proc, ' ') &&
          strstr(cmdline, argv[1]) &&
          !strstr(cmdline, argv[0]) )
      {
        snprintf(path_proc, sizeof(path_proc), "/proc/%s/%s", dir_proc->d_name, "smaps");
     total_smaps(pid_proc, path_proc, cmdline);
   }
    }
  }

  if ( errno )
    error(EXIT_FAILURE, errno, "fail");

  return EXIT_SUCCESS;
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */