149 lines
2.9 KiB
C
149 lines
2.9 KiB
C
/***
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* Getting and setting
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* environment variables.
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* @module environment
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*/
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#include <stdlib.h>
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#include <errno.h>
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#ifdef BSD
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# include <string.h>
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#endif
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#include <lua.h>
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#include <lauxlib.h>
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#include "lenvironment.h"
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#include "lcallisto.h"
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#include "util.h"
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extern char **environ;
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/***
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* Returns the value of the given environment
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* variable.
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*
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* If *var* does not exist in the environment
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* and *defaultvalue* is not nil,
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* *defaultvalue* will be returned.
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*
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* @function get
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* @usage environment.get("HOME", "/root")
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* @tparam string var The environment variable to get.
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* @param[opt] defaultvalue The value to return in case the environment variable was not found.
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*/
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static int
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environment_get(lua_State *L)
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{
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const char *variable;
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char *ret;
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variable = luaL_checkstring(L, 1);
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ret = getenv(variable);
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if (ret == NULL)
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if (!lua_isnoneornil(L, 2))
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lua_pushvalue(L, 2);
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else
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lua_pushnil(L);
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else
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lua_pushstring(L, ret);
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return 1;
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}
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/***
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* Sets the value of the given environment variable.
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*
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* This function will throw an error if the value of
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* *var* is invalid for the name of an environment
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* variable, or if there is insufficient memory
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* available to perform the operation.
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*
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* @function set
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* @usage environment.set("MYVAR", "1")
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* @tparam string var The environment variable to set.
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* @tparam string value The value to set for *var*.
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*/
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static int
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environment_set(lua_State *L)
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{
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int ret;
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const char *variable;
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const char *value;
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variable = luaL_checkstring(L, 1);
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value = luaL_checkstring(L, 2);
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ret = setenv(variable, value, 1);
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if (ret == 0)
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return 0;
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switch (errno) {
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case EINVAL:
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return luaL_error(L, "invalid input string");
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break;
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case ENOMEM:
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return luaL_error(L, "insufficient memory");
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break;
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}
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return 0;
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}
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/***
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* Clears the environment.
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*
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* If *var* is not nil, only clears the value of that
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* environment variable (not the whole environment).
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*
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* This function will throw an error if the value of
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* *var* is invalid for the name of an environment
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* variable, or if there is insufficient memory
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* available to perform the operation.
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*
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* @function clear
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* @usage environment.clear("MYVAR")
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* @tparam[opt] string var The environment variable to clear.
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*/
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static int
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environment_clear(lua_State *L)
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{
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const char *variable;
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int ret;
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if (lua_isnoneornil(L, 1)) {
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environ = NULL;
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return 0;
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}
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variable = luaL_checkstring(L, 1);
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ret = unsetenv(variable);
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if (ret == 0)
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return 0;
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switch (errno) {
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case EINVAL:
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return luaL_error(L, "invalid input string");
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break;
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case ENOMEM:
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return luaL_error(L, "insufficient memory");
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break;
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}
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return 0;
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}
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static const luaL_Reg envlib[] = {
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{"get", environment_get},
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{"set", environment_set},
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{"clear", environment_clear},
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{NULL, NULL}
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};
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int
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callistoopen_environment(lua_State *L)
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{
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luaL_newlib(L, envlib);
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return 1;
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}
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