85 lines
1.6 KiB
C
85 lines
1.6 KiB
C
#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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extern char ** environ;
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extern int _environ_size;
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static int why_no_strnstr(char * a, char * b, int n) {
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for (int i = 0; (i < n) && (a[i]) && (b[i]); ++i) {
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if (a[i] != b[i]) {
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return 1;
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}
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}
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return 0;
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}
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int unsetenv(const char * str) {
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int last_index = -1;
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int found_index = -1;
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int len = strlen(str);
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for (int i = 0; environ[i]; ++i) {
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if (found_index == -1 && (strstr(environ[i], str) == environ[i] && environ[i][len] == '=')) {
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found_index = i;
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}
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last_index = i;
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}
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if (found_index == -1) {
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/* not found = success */
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return 0;
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}
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if (last_index == found_index) {
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/* Was last element */
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environ[last_index] = NULL;
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return 0;
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}
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/* Was not last element, swap ordering */
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environ[found_index] = environ[last_index];
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environ[last_index] = NULL;
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return 0;
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}
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int putenv(char * string) {
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char name[strlen(string)+1];
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strcpy(name, string);
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char * c = strchr(name, '=');
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if (!c) {
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return 1;
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}
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*c = NULL;
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int s = strlen(name);
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int i;
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for (i = 0; i < (_environ_size - 1) && environ[i]; ++i) {
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if (!why_no_strnstr(name, environ[i], s) && environ[i][s] == '=') {
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environ[i] = string;
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return 0;
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}
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}
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/* Not found */
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if (i == _environ_size - 1) {
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int _new_environ_size = _environ_size * 2;
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char ** new_environ = malloc(sizeof(char*) * _new_environ_size);
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int j = 0;
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while (j < _new_environ_size && environ[j]) {
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new_environ[j] = environ[j];
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j++;
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}
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while (j < _new_environ_size) {
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new_environ[j] = NULL;
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j++;
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}
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_environ_size = _new_environ_size;
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environ = new_environ;
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}
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environ[i] = string;
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return 0;
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}
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