mdw@git.distorted.org.uk Git - qmail/blob - env.c

   1 /* env.c, envread.c, env.h: environ library
   2 Daniel J. Bernstein, djb@silverton.berkeley.edu.
   3 Depends on str.h, alloc.h.
   4 Requires environ.
   5 19960113: rewrite. warning: interface is different.
   6 No known patent problems.
   7 */
   8
   9 #include "str.h"
  10 #include "alloc.h"
  11 #include "env.h"
  12
  13 int env_isinit = 0; /* if env_isinit: */
  14 static int ea; /* environ is a pointer to ea+1 char*'s. */
  15 static int en; /* the first en of those are ALLOCATED. environ[en] is 0. */
  16
  17 static void env_goodbye(i) int i;
  18 {
  19  alloc_free(environ[i]);
  20  environ[i] = environ[--en];
  21  environ[en] = 0;
  22 }
  23
  24 static char *null = 0;
  25
  26 void env_clear()
  27 {
  28  if (env_isinit) while (en) env_goodbye(0);
  29  else environ = &null;
  30 }
  31
  32 static void env_unsetlen(s,len) char *s; int len;
  33 {
  34  int i;
  35  for (i = en - 1;i >= 0;--i)
  36    if (!str_diffn(s,environ[i],len))
  37      if (environ[i][len] == '=')
  38        env_goodbye(i);
  39 }
  40
  41 int env_unset(s) char *s;
  42 {
  43  if (!env_isinit) if (!env_init()) return 0;
  44  env_unsetlen(s,str_len(s));
  45  return 1;
  46 }
  47
  48 static int env_add(s) char *s;
  49 {
  50  char *t;
  51  t = env_findeq(s);
  52  if (t) env_unsetlen(s,t - s);
  53  if (en == ea)
  54   {
  55    ea += 30;
  56    if (!alloc_re(&environ,(en + 1) * sizeof(char *),(ea + 1) * sizeof(char *)))
  57     { ea = en; return 0; }
  58   }
  59  environ[en++] = s;
  60  environ[en] = 0;
  61  return 1;
  62 }
  63
  64 int env_put(s) char *s;
  65 {
  66  char *u;
  67  if (!env_isinit) if (!env_init()) return 0;
  68  u = alloc(str_len(s) + 1);
  69  if (!u) return 0;
  70  str_copy(u,s);
  71  if (!env_add(u)) { alloc_free(u); return 0; }
  72  return 1;
  73 }
  74
  75 int env_put2(s,t) char *s; char *t;
  76 {
  77  char *u;
  78  int slen;
  79  if (!env_isinit) if (!env_init()) return 0;
  80  slen = str_len(s);
  81  u = alloc(slen + str_len(t) + 2);
  82  if (!u) return 0;
  83  str_copy(u,s);
  84  u[slen] = '=';
  85  str_copy(u + slen + 1,t);
  86  if (!env_add(u)) { alloc_free(u); return 0; }
  87  return 1;
  88 }
  89
  90 int env_init()
  91 {
  92  char **newenviron;
  93  int i;
  94  for (en = 0;environ[en];++en) ;
  95  ea = en + 10;
  96  newenviron = (char **) alloc((ea + 1) * sizeof(char *));
  97  if (!newenviron) return 0;
  98  for (en = 0;environ[en];++en)
  99   {
 100    newenviron[en] = alloc(str_len(environ[en]) + 1);
 101    if (!newenviron[en])
 102     {
 103      for (i = 0;i < en;++i) alloc_free(newenviron[i]);
 104      alloc_free(newenviron);
 105      return 0;
 106     }
 107    str_copy(newenviron[en],environ[en]);
 108   }
 109  newenviron[en] = 0;
 110  environ = newenviron;
 111  env_isinit = 1;
 112  return 1;
 113 }