113 lines
2.2 KiB
C
113 lines
2.2 KiB
C
/* env.c, envread.c, env.h: environ library
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Daniel J. Bernstein, djb@silverton.berkeley.edu.
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Depends on str.h, alloc.h.
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Requires environ.
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19960113: rewrite. warning: interface is different.
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No known patent problems.
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*/
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#include "str.h"
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#include "alloc.h"
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#include "env.h"
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int env_isinit = 0; /* if env_isinit: */
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static int ea; /* environ is a pointer to ea+1 char*'s. */
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static int en; /* the first en of those are ALLOCATED. environ[en] is 0. */
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static void env_goodbye(i) int i;
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{
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alloc_free(environ[i]);
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environ[i] = environ[--en];
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environ[en] = 0;
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}
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static char *null = 0;
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void env_clear()
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{
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if (env_isinit) while (en) env_goodbye(0);
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else environ = &null;
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}
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static void env_unsetlen(s,len) char *s; int len;
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{
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int i;
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for (i = en - 1;i >= 0;--i)
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if (!str_diffn(s,environ[i],len))
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if (environ[i][len] == '=')
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env_goodbye(i);
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}
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int env_unset(s) char *s;
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{
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if (!env_isinit) if (!env_init()) return 0;
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env_unsetlen(s,str_len(s));
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return 1;
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}
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static int env_add(s) char *s;
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{
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char *t;
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t = env_findeq(s);
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if (t) env_unsetlen(s,t - s);
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if (en == ea)
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{
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ea += 30;
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if (!alloc_re(&environ,(en + 1) * sizeof(char *),(ea + 1) * sizeof(char *)))
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{ ea = en; return 0; }
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}
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environ[en++] = s;
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environ[en] = 0;
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return 1;
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}
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int env_put(s) char *s;
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{
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char *u;
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if (!env_isinit) if (!env_init()) return 0;
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u = alloc(str_len(s) + 1);
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if (!u) return 0;
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str_copy(u,s);
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if (!env_add(u)) { alloc_free(u); return 0; }
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return 1;
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}
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int env_put2(s,t) char *s; char *t;
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{
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char *u;
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int slen;
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if (!env_isinit) if (!env_init()) return 0;
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slen = str_len(s);
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u = alloc(slen + str_len(t) + 2);
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if (!u) return 0;
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str_copy(u,s);
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u[slen] = '=';
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str_copy(u + slen + 1,t);
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if (!env_add(u)) { alloc_free(u); return 0; }
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return 1;
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}
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int env_init()
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{
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char **newenviron;
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int i;
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for (en = 0;environ[en];++en) ;
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ea = en + 10;
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newenviron = (char **) alloc((ea + 1) * sizeof(char *));
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if (!newenviron) return 0;
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for (en = 0;environ[en];++en)
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{
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newenviron[en] = alloc(str_len(environ[en]) + 1);
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if (!newenviron[en])
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{
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for (i = 0;i < en;++i) alloc_free(newenviron[i]);
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alloc_free(newenviron);
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return 0;
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}
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str_copy(newenviron[en],environ[en]);
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}
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newenviron[en] = 0;
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environ = newenviron;
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env_isinit = 1;
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return 1;
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}
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