116 lines
2.7 KiB
C
116 lines
2.7 KiB
C
#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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static void free_var(const char* string)
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{
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// TODO: Implement me!
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}
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char* getenv(const char* name)
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{
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size_t len = strlen(name);
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for (int i = 0; environ[i]; i++) {
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const char* envv = environ[i];
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char* eqpos = strchr(envv, '=');
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if (!eqpos) {
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continue;
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}
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size_t curlen = (size_t)(eqpos - envv);
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if (curlen == len && strncmp(name, envv, len) == 0) {
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return (char*)&envv[len + 1];
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}
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}
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return NULL;
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}
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int setenv(const char* name, const char* value, int overwrite)
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{
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if (!overwrite && getenv(name)) {
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return 0;
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}
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int name_len = strlen(name);
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int value_len = strlen(value);
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int len = name_len + 1 + value_len;
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char* string = (char*)malloc(len + 1);
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strncpy(string, name, name_len);
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string[name_len] = '=';
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strncpy(&string[name_len + 1], value, value_len);
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string[len] = '\0';
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return putenv(string);
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}
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int putenv(char* string)
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{
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char* pos = strchr(string, '=');
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if (!pos) {
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return unsetenv(string);
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}
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size_t len = (size_t)(pos - string);
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int env_i = 0;
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for (; environ[env_i]; env_i++) {
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const char* envv = environ[env_i];
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char* eqpos = strchr(envv, '=');
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if (!eqpos) {
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continue;
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}
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size_t curlen = (size_t)(eqpos - envv);
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if (len != curlen) {
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continue;
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}
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if (strncmp(string, envv, len) == 0) {
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free_var(envv);
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environ[env_i] = string;
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return 0;
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}
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}
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char** new_environ = (char**)malloc(sizeof(char*) * (env_i + 2));
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for (int i = 0; i < env_i; i++) {
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new_environ[i] = environ[i];
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}
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new_environ[env_i] = string;
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new_environ[env_i + 1] = NULL;
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extern int __environ_malloced;
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if (__environ_malloced) {
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free(environ);
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}
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environ = new_environ;
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__environ_malloced = 1;
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return 0;
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}
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int unsetenv(const char* name)
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{
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size_t len = strlen(name);
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int env_i = 0;
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int remove_pos = 0;
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const char* remove_env = NULL;
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for (; environ[env_i]; env_i++) {
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const char* envv = environ[env_i];
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char* eqpos = strchr(envv, '=');
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if (!eqpos) {
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continue;
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}
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size_t curlen = (size_t)(eqpos - envv);
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if (len != curlen) {
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continue;
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}
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if (strncmp(name, envv, len) == 0) {
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remove_pos = env_i;
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remove_env = envv;
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}
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}
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size_t move_len = ((env_i - 1) - remove_pos) * sizeof(char*);
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memmove(&environ[remove_pos], &environ[remove_pos + 1], move_len);
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free_var(remove_env);
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return 0;
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}
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