mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-21 06:33:31 +00:00
141 lines
3.4 KiB
C++
141 lines
3.4 KiB
C++
/*
|
|
* \brief Populate arguments and environment from config
|
|
* \author Christian Prochaska
|
|
* \date 2020-08-14
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2020 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU Affero General Public License version 3.
|
|
*/
|
|
|
|
#ifndef _INCLUDE__LIBC__ARGS_H_
|
|
#define _INCLUDE__LIBC__ARGS_H_
|
|
|
|
/* Genode includes */
|
|
#include <libc/component.h>
|
|
#include <util/xml_node.h>
|
|
|
|
/* libc includes */
|
|
#include <stdlib.h> /* 'malloc' */
|
|
|
|
static void populate_args_and_env(Libc::Env &env, int &argc, char **&argv, char **&envp)
|
|
{
|
|
using Genode::Xml_node;
|
|
using Genode::Xml_attribute;
|
|
|
|
env.config([&] (Xml_node const &node) {
|
|
|
|
int envc = 0;
|
|
|
|
/* count the number of arguments and environment variables */
|
|
node.for_each_sub_node([&] (Xml_node const &node) {
|
|
/* check if the 'value' attribute exists */
|
|
if (node.has_type("arg") && node.has_attribute("value"))
|
|
++argc;
|
|
else
|
|
if (node.has_type("env") && node.has_attribute("key") && node.has_attribute("value"))
|
|
++envc;
|
|
});
|
|
|
|
if (argc == 0 && envc == 0) {
|
|
/*
|
|
* If argc is zero then argv is still a NULL-terminated array.
|
|
*/
|
|
static char const *args[] = { nullptr, nullptr };
|
|
argc = 0;
|
|
argv = (char**)&args;
|
|
envp = &argv[1];
|
|
return; /* from lambda */
|
|
}
|
|
|
|
/* arguments and environment are arranged System V style (but don't count on it) */
|
|
argv = (char**)malloc((argc + envc + 2) * sizeof(char*));
|
|
envp = &argv[argc+1];
|
|
|
|
/* read the arguments */
|
|
int arg_i = 0;
|
|
int env_i = 0;
|
|
node.for_each_sub_node([&] (Xml_node const &node) {
|
|
|
|
/* insert an argument */
|
|
if (node.has_type("arg")) {
|
|
|
|
Xml_attribute attr = node.attribute("value");
|
|
attr.with_raw_value([&] (char const *start, size_t length) {
|
|
|
|
size_t const size = length + 1; /* for null termination */
|
|
|
|
argv[arg_i] = (char *)malloc(size);
|
|
|
|
Genode::copy_cstring(argv[arg_i], start, size);
|
|
});
|
|
|
|
++arg_i;
|
|
}
|
|
else
|
|
|
|
/* insert an environment variable */
|
|
if (node.has_type("env")) try {
|
|
|
|
auto check_attr = [] (Xml_node node, auto key) {
|
|
if (!node.has_attribute(key))
|
|
Genode::warning("<env> node lacks '", key, "' attribute"); };
|
|
|
|
check_attr(node, "key");
|
|
check_attr(node, "value");
|
|
|
|
Xml_attribute const key = node.attribute("key");
|
|
Xml_attribute const value = node.attribute("value");
|
|
|
|
using namespace Genode;
|
|
|
|
/*
|
|
* An environment variable has the form <key>=<value>, followed
|
|
* by a terminating zero.
|
|
*/
|
|
size_t const var_size = key .value_size() + 1
|
|
+ value.value_size() + 1;
|
|
|
|
envp[env_i] = (char*)malloc(var_size);
|
|
|
|
size_t pos = 0;
|
|
|
|
/* append characters to env variable with zero termination */
|
|
auto append = [&] (char const *s, size_t len) {
|
|
|
|
if (pos + len >= var_size) {
|
|
/* this should never happen */
|
|
warning("truncated environment variable: ", node);
|
|
return;
|
|
}
|
|
|
|
copy_cstring(envp[env_i] + pos, s, len + 1);
|
|
pos += len;
|
|
};
|
|
|
|
key.with_raw_value([&] (char const *start, size_t length) {
|
|
append(start, length); });
|
|
|
|
append("=", 1);
|
|
|
|
value.with_raw_value([&] (char const *start, size_t length) {
|
|
append(start, length); });
|
|
|
|
++env_i;
|
|
|
|
}
|
|
catch (Xml_node::Nonexistent_sub_node) { }
|
|
catch (Xml_node::Nonexistent_attribute) { }
|
|
});
|
|
|
|
/* argv and envp are both NULL terminated */
|
|
argv[arg_i] = NULL;
|
|
envp[env_i] = NULL;
|
|
});
|
|
}
|
|
|
|
#endif /* _INCLUDE__LIBC__ARGS_H_ */
|