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commands: remove program options
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This patch partially addresses #1014 and removes usage
of boost program_options library in core/commands.cc.
More specifically it reimplements handling of runscript
options: '--env=VAR=abc' by using simple logic to detect and parse
individual argv elements.

In order to fully address #1014 we also need to modify loader.cc
to not use program options.

Signed-off-by: Waldemar Kozaczuk <jwkozaczuk@gmail.com>
Message-Id: <20190928133933.11202-1-jwkozaczuk@gmail.com>
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@wkozaczuk @nyh
wkozaczuk authored and nyh committed Oct 3, 2019
1 parent c08cebc commit a4e48ba
Showing 1 changed file with 46 additions and 65 deletions.
111 changes: 46 additions & 65 deletions core/commands.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@

#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/program_options.hpp>
#include <osv/power.hh>
#include <osv/commands.hh>
#include <osv/align.hh>
Expand Down Expand Up @@ -135,76 +134,58 @@ Applying all options before running any command is also safer than trying to
apply options for each script at script execution (second script would modify
environment setup by the first script, causing a race).
*/
static void runscript_process_options(std::vector<std::vector<std::string> >& result) {
namespace bpo = boost::program_options;
namespace bpos = boost::program_options::command_line_style;
// don't allow --foo bar (require --foo=bar) so we can find the first non-option
// argument
int style = bpos::unix_style & ~(bpos::long_allow_next | bpos::short_allow_next);
bpo::options_description desc("OSv runscript options");
desc.add_options()
("env", bpo::value<std::vector<std::string>>(), "set Unix-like environment variable (putenv())");
static void runscript_process_options_usage(std::string &message) {
std::cout << message << "\n";
std::cout << "OSv runscript options:\n";
std::cout << " --env=arg set Unix-like environment variable (putenv())\n";
osv::poweroff();
}

static void runscript_process_options(std::vector<std::vector<std::string> >& result) {
for (size_t ii=0; ii<result.size(); ii++) {
auto cmd = result[ii];
bpo::variables_map vars;

std::vector<const char*> args = { "dummy-string" };
// due to https://svn.boost.org/trac/boost/ticket/6991, we can't terminate
// command line parsing on the executable name, so we need to look for it
// ourselves
auto ac = cmd.size();
auto av = std::vector<const char*>();
av.reserve(ac);
for (auto& prm: cmd) {
av.push_back(prm.c_str());
}
auto nr_options = std::find_if(av.data(), av.data() + ac,
[](const char* arg) { return arg[0] != '-'; }) - av.data();
std::copy(av.data(), av.data() + nr_options, std::back_inserter(args));

try {
bpo::store(bpo::parse_command_line(args.size(), args.data(), desc, style), vars);
} catch(std::exception &e) {
std::cout << e.what() << '\n';
std::cout << desc << '\n';
osv::poweroff();
}
bpo::notify(vars);

if (vars.count("env")) {
for (auto t : vars["env"].as<std::vector<std::string>>()) {
size_t pos = t.find("?=");
std::string key, value;
if (std::string::npos == pos) {
// the basic "KEY=value" syntax
size_t pos2 = t.find("=");
assert(std::string::npos != pos2);
key = t.substr(0, pos2);
value = t.substr(pos2+1);
//debug("Setting in environment (def): %s=%s\n", key, value);
}
else {
// "KEY?=value", makefile-like syntax, set variable only if not yet set
key = t.substr(0, pos);
value = t.substr(pos+2);
if (nullptr != getenv(key.c_str())) {
// key already used, do not overwrite it
//debug("NOT setting in environment (makefile): %s=%s\n", key, value);
key = "";
}
else {
//debug("Setting in environment (makefile): %s=%s\n", key, value);
}
}

if (key.length() > 0) {
// we have something to set
expand_environ_vars(value);
debug("Setting in environment: %s=%s\n", key, value);
setenv(key.c_str(), value.c_str(), 1);
int nr_options = 0;
const char *env_prefix = "--env=";
for (auto arg : cmd) {
if (arg.empty() || arg[0] != '-') {
break;
}
nr_options++;

if (arg.find(env_prefix) != 0) {
auto message = std::string("unrecognised option '") + arg + "'";
runscript_process_options_usage(message);
}

auto t = arg.substr(strlen(env_prefix),std::string::npos);
size_t pos = t.find("?=");
std::string key, value;
if (std::string::npos == pos) {
// the basic "KEY=value" syntax
size_t pos2 = t.find("=");
if (std::string::npos == pos2) {
auto message = std::string("expected 'KEY(?)=value' but instead got '") + arg + "'";
runscript_process_options_usage(message);
}
key = t.substr(0, pos2);
value = t.substr(pos2+1);
}
else {
// "KEY?=value", makefile-like syntax, set variable only if not yet set
key = t.substr(0, pos);
value = t.substr(pos+2);
if (nullptr != getenv(key.c_str())) {
// key already used, do not overwrite it
key = "";
}
}

if (key.length() > 0) {
// we have something to set
expand_environ_vars(value);
debug("Setting in environment: %s=%s\n", key, value);
setenv(key.c_str(), value.c_str(), 1);
}
}

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