#include "env.h"

#include "alloc.h"
#include "str.h"

/**
  @file   env.c
  @author djb
  @source ucspi-tcp
  @brief  setting up environment after fork
*/

extern /*@null@*/ char *env_get(char *s)
{
  int i;
  unsigned int len;

  if (!s) return 0;
  len = str_len(s);
  for (i = 0; environ[i]; ++i)
    if (str_start(environ[i], s) && (environ[i][len] == '=')) return environ[i] + len + 1;
  return 0;
}

extern char *env_findeq(char *s)
{
  for (; *s; ++s)
    if (*s == '=') return s;
  return 0;
}

int env_isinit = 0; /* if env_isinit: */
static int ea;      /* environ is a pointer to ea+1 char*'s. */
static int en;      /* the first en of those are ALLOCATED. environ[en] is 0. */

static void env_del(int i)
{
  alloc_free(environ[i]);
  environ[i] = environ[--en];
  environ[en] = 0;
}

static void env_unsetlen(char *s, int len)
{
  int i;

  for (i = en - 1; i >= 0; --i)
    if (!str_diffn(s, environ[i], len))
      if (environ[i][len] == '=') env_del(i);
}

int env_unset(char *s)
{
  if (!env_isinit)
    if (!env_init()) return 0;
  env_unsetlen(s, str_len(s));
  return 1;
}

int env_set(char *s)
{
  char *t;

  t = env_findeq(s);
  if (t) env_unsetlen(s, t - s);
  if (en == ea) {
    ea += 30;
    if (!alloc_re(&environ, (en + 1) * sizeof(char *), (ea + 1) * sizeof(char *))) {
      ea = en;
      return 0;
    }
  }
  environ[en++] = s;
  environ[en] = 0;
  return 1;
}

int env_puts(char *s)
{
  char *u;

  if (!env_isinit)
    if (!env_init()) return 0;
  u = alloc(str_len(s) + 1);
  if (!u) return 0;
  str_copy(u, s);
  if (!env_set(u)) {
    alloc_free(u);
    return 0;
  }
  return 1;
}

int env_put(char *name, char *value)
{
  char *ln;
  int len;

  if (!env_isinit)
    if (!env_init()) return 0;
  len = str_len(name);
  ln = alloc(len + str_len(value) + 2);
  if (!ln) return 0;
  str_copy(ln, name);
  ln[len] = '=';
  str_copy(ln + len + 1, value);
  if (!env_set(ln)) {
    alloc_free(ln);
    return 0;
  }
  return 1;
}

int env_init(void)
{
  char **newenviron;
  int i;

  for (en = 0; environ[en]; ++en);
  ea = en + 10;
  newenviron = (char **)alloc((ea + 1) * sizeof(char *));
  if (!newenviron) return 0;

  for (en = 0; environ[en]; ++en) {
    newenviron[en] = alloc(str_len(environ[en]) + 1);
    if (!newenviron[en]) {
      for (i = 0; i < en; ++i) alloc_free(newenviron[i]);
      alloc_free(newenviron);
      return 0;
    }
    str_copy(newenviron[en], environ[en]);
  }

  newenviron[en] = 0;
  environ = newenviron;
  env_isinit = 1;
  return 1;
}

static char *null = 0;

void env_clear()
{
  if (env_isinit)
    while (en) env_del(0);
  else
    environ = &null;
}

extern char *env_pick()
{
  return environ[0];
}