1 /* env.c, envread.c, env.h: environ library
2 Daniel J. Bernstein, djb@silverton.berkeley.edu.
3 Depends on str.h, alloc.h.
5 19960113: rewrite. warning: interface is different.
6 No known patent problems.
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. */
17 static void env_goodbye(i) int i;
19 alloc_free(environ[i]);
20 environ[i] = environ[--en];
24 static char *null = 0;
28 if (env_isinit) while (en) env_goodbye(0);
32 static void env_unsetlen(s,len) char *s; int len;
35 for (i = en - 1;i >= 0;--i)
36 if (!str_diffn(s,environ[i],len))
37 if (environ[i][len] == '=')
41 int env_unset(s) char *s;
43 if (!env_isinit) if (!env_init()) return 0;
44 env_unsetlen(s,str_len(s));
48 static int env_add(s) char *s;
52 if (t) env_unsetlen(s,t - s);
56 if (!alloc_re(&environ,(en + 1) * sizeof(char *),(ea + 1) * sizeof(char *)))
57 { ea = en; return 0; }
64 int env_put(s) char *s;
67 if (!env_isinit) if (!env_init()) return 0;
68 u = alloc(str_len(s) + 1);
71 if (!env_add(u)) { alloc_free(u); return 0; }
75 int env_put2(s,t) char *s; char *t;
79 if (!env_isinit) if (!env_init()) return 0;
81 u = alloc(slen + str_len(t) + 2);
85 str_copy(u + slen + 1,t);
86 if (!env_add(u)) { alloc_free(u); return 0; }
94 for (en = 0;environ[en];++en) ;
96 newenviron = (char **) alloc((ea + 1) * sizeof(char *));
97 if (!newenviron) return 0;
98 for (en = 0;environ[en];++en)
100 newenviron[en] = alloc(str_len(environ[en]) + 1);
103 for (i = 0;i < en;++i) alloc_free(newenviron[i]);
104 alloc_free(newenviron);
107 str_copy(newenviron[en],environ[en]);
110 environ = newenviron;