/* Parts of the Unix library */

quote(C,"#include <stdlib.h>")
quote(C,"#include <stdio.h>")
quote(C,"#include <sys/types.h>")
quote(C,"#include <sys/wait.h>")
quote(C,"#include <dirent.h>")
quote(C,"#include <unistd.h>")
quote(C,"#include <sys/stat.h>")
quote(C,"#include <sys/time.h>")
quote(C,"#include <fcntl.h>")

quote (C, "
  /* Wrapping of return code for wait */

  union process_status { int code; };

  enum { WEXITED, WSIGNALED, WSTOPPED };

  static void decode_status(int status, int * kind, union process_status * p)
  {
    if (WIFEXITED(status)) {
      *kind = WEXITED; p->code = WEXITSTATUS(status);
    } else if (WIFSIGNALED(status)) {
      *kind = WSIGNALED; p->code = WTERMSIG(status);
    } else {
      *kind = WSTOPPED; p->code = WSTOPSIG(status);
    }
  }

  int read2(int fd, int len, int * rd, char * buf)
  {
    int retcode = read(fd, buf, len);
    if (retcode != -1) { *rd = retcode; retcode = 0; }
    return retcode;
  }

  typedef DIR * dir_handle;
  typedef struct dirent dirent;
  typedef fd_set * file_descr_set;

  extern char ** environ;
")

[string*, null_terminated] char ** environment(void)
   quote(call, "_res = environ;");

[string] char * getenv([in,string] char * varname);

void putenv([in,string] char * name_val);

int execv([in,string] char * path,
          [in,null_terminated,string*] char ** argv);

int execve([in,string] char * path, 
           [in,null_terminated,string*] char ** argv,
           [in,null_terminated,string*] char ** env);

int fork(void);

union process_status {
  case WEXITED: int code;
  case WSIGNALED: int code;
  case WSTOPPED: int code;
};

int wait([out] int * kind,
         [out,switch_is(*kind)] union process_status * p)
  quote(call,
    " { int status;
        _res = wait(&status);
        if (_res != -1) decode_status(status, kind, p); }");

void system([in,string] char * cmd,
            [out] int * kind,
            [out,switch_is(*kind)] union process_status * p)
  quote(call,
    "  { int ret = system(cmd);
         decode_status(ret, kind, p); } ");

int getpid(void);
int getppid(void);
int nice(int pid);

enum open_flags {
  O_RDONLY, O_WRONLY, O_RDWR, O_CREAT,
  O_EXCL, O_TRUNC, O_APPEND, O_NONBLOCK
};

int openfile([in,string] char * name,
             [in,set] enum open_flags flags,
             [in] int perms)
  quote(call, " _res = open(name, flags, perms); ");

int close([in] int fd);

/* read in place */
int read([in] int fd, [in,string,size_is(len)] char * buf, [in] int len);

/* read with copy */
void read2([in] int fd, [in] int len, [out] int *rd,
          [out,string,size_is(len),length_is(*rd)] char * buf)
  quote(call,
    " *rd = read(fd, buf, len);
      if (*rd == -1) failwith(\"read2\"); ");

/* write */
int write([in] int fd, [in,string,size_is(len)] char * buf, [in] int len);

/* seeking */
enum seek_command { SEEK_SET, SEEK_CUR, SEEK_END };

int lseek(int fd, int ofs, enum seek_command cmd);

int truncate([string] char * filename, int size);

int ftruncate(int fd, int size);

/* stats */
/* Note: the types given are not the C representation types, */
/* but just the conversion types.  So it's OK to say st_dev is an int */
/* even if actually it's a short.  We can even claim that st_?time */
/* are doubles while actually they are integers! */
struct stat {
  int st_dev, st_ino;
  int st_mode;
  int st_nlink;
  int st_uid, st_gid;
  int st_rdev;
  int st_size;
  long st_blksize, st_blocks;
  double st_atime, st_mtime, st_ctime;
};

int stat([string] char * filename, [out] struct stat * st);
int lstat([string] char * filename, [out] struct stat * st);
int fstat(int fd, [out] struct stat * st);

/* Operations on file names */

int unlink([string] char * filename);
int rename([string] char * filename, [string] char * newname);
int link([string] char * filename, [string] char * newname);

/* Directories */

typedef [abstract,ptr] void * dir_handle;

dir_handle opendir([string] char * filename)
  quote(call,
    " _res = opendir(filename);
      if (_res == NULL) failwith(\"opendir\"); ");

typedef struct {
  [string] char d_name[256];   // NAME_MAX in fact
} dirent;

[unique] dirent * readdir(dir_handle d);

void rewinddir(dir_handle d);
void closedir(dir_handle d);

/* pipes */

int pipe([out] int fds[2]);

/* select */

typedef [abstract] void * file_descr_set;

void FD_ZERO(file_descr_set s);
void FD_SET(int fd, file_descr_set s);
void FD_CLR(int fd, file_descr_set s);
boolean FD_ISSET(int fd, file_descr_set s);

struct timeval {
  int tv_sec;
  int tv_usec;
};

int select(int n,
           file_descr_set read,
           file_descr_set write,
           file_descr_set except,
           [unique] struct timeval * timeout);