C++ Library containing a lot of needful things: Stack Trace, Command Line Parser, Resource Handling, Configuration Files, Unix Command Execution, Directories, Regular Expressions, Tokenizer, Function Trace, Standard Extensions.
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/** @file
$Id$
$Date$
$Author$
@copy © Marc Wäckerlin
@license LGPL, see file <a href="license.html">COPYING</a>
$Log$
Revision 1.6 2004/12/17 16:28:51 marc
stable implementation with select for both executes
Revision 1.5 2004/12/14 20:30:09 marc
added possibility to pass string to stdin of child process
Revision 1.4 2004/08/28 16:21:25 marc
mrw-c++-0.92 (mrw)
- new file: version.cpp
- new file header for all sources
- work around warning in mrw::auto<T>
- possibility to compile without log4cxx
- work around bugs in demangle.h and libiberty.h
- corrections in documentation
- added simple tracing mechanism
- more warnings
- small corrections in Auto<>::Free and a new test for it
- possibility to compile without stack trace
*/
#include <mrw/exec.hpp>
#include <mrw/unistd.hpp>
#include <mrw/exception.hpp>
#include <mrw/stdext.hpp> // max
#include <sys/wait.h> // waitpid
#include <unistd.h> // fork, exec
#include <string.h> // memcpy
#include <assert.h> // assert
mrw::ExecutionFailedExc::ExecutionFailedExc(const std::string& w,
const std::string& c)
throw(std::bad_exception):
_what(std::string("mrw::Exec: command execution failed\n")+
std::string(" failed command was: \""+c+"\"\n")+
std::string(" error was: \"")+w+'"') {
/**
@c what looks like:
@verbatim
mrw::Exec: command execution failed
failed command was: "/bin/OOOOPS -v -q --crash"
error was: "execution failed"
@endverbatim
*/
}
mrw::Cmd::Cmd(const std::string& c) throw(std::bad_exception) {
_cmd.push_back(c);
}
mrw::Cmd& mrw::Cmd::operator,(const std::string& arg)
throw(std::bad_exception) {
_cmd.push_back(arg);
return *this;
}
mrw::Cmd& mrw::Cmd::operator<<(const std::string& arg)
throw(std::bad_exception) {
_cmd.push_back(arg);
return *this;
}
mrw::Cmd::operator std::string() const throw(std::bad_exception) {
ArgList::const_iterator it(_cmd.begin());
std::string c(*it);
while (++it!=_cmd.end()) c+=' '+*it;
return c;
}
mrw::Cmd::operator mrw::Exec() const throw(std::bad_exception) {
return mrw::Exec(*this);
}
mrw::Exec mrw::Cmd::execute(bool exc) const throw(std::exception) {
return mrw::Exec(*this).execute(exc);
}
mrw::Exec mrw::Cmd::execute(const std::string& input, bool exc) const
throw(std::exception) {
return mrw::Exec(*this).execute(input, exc);
}
const char* mrw::Cmd::path() const throw(std::bad_exception) {
return _cmd.front().c_str();
}
char** mrw::Cmd::args() const throw(std::bad_exception) {
if (_cmd.size()==0) return 0;
char** array = new char*[_cmd.size()+1];
int i(0);
for (ArgList::const_iterator it(_cmd.begin()); it!=_cmd.end(); ++it)
memcpy(array[i++]=new char[it->size()+1], it->c_str(), it->size()+1);
array[i] = 0;
return array;
}
mrw::Exec::Exec(const mrw::Cmd& c) throw(std::bad_exception):
_cmd(new mrw::Cmd(c)), _success(false) {
}
mrw::Exec::Exec(const mrw::Exec& e) throw(std::bad_exception):
_cmd(new mrw::Cmd(*e._cmd)),
_res(e._res), _err(e._err), _success(e._success) {
}
mrw::Exec::~Exec() throw() {
delete _cmd;
}
mrw::Exec& mrw::Exec::operator=(const mrw::Exec& e) throw(std::bad_exception) {
if (this==&e) return *this;
*_cmd=*e._cmd; _res=e._res; _err=e._err; _success=e._success;
return *this;
}
mrw::Exec& mrw::Exec::execute(bool exc) throw(std::exception) {
/** This method calls @c fork, sets up a pipe connection to pass @c
stdout and @c stderr from the child process to the parent
process using mrw::Pipe and calls @c execvp to execute the
program. */
_success = false;
_res = _err = "";
mrw::Pipe stdOut, stdErr;
21 years ago
if (!stdOut || !stdErr)
throw mrw::ExecutionFailedExc("cannot create pipe", *_cmd);
pid_t pid(fork());
if (pid<0)
throw ExecutionFailedExc("cannot fork", *_cmd);
if (pid) { // parent
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stdOut.close_out();
stdErr.close_out();
if (!stdOut || !stdErr)
throw ExecutionFailedExc("cannot close pipe", *_cmd);
ssize_t num1(-1), num2(-1);
fd_set readfds;
char buf[4096];
int res(0), s(0);
while (num1||num2) try { // not all end of file
if (!res && (res=waitpid(pid, &s, WNOHANG)))
if (res!=pid || WIFEXITED(s)!=0 && WEXITSTATUS(s)!=0)
throw ExecutionFailedExc("execution failed", *_cmd);
// select...
FD_ZERO(&readfds);
if (num1) FD_SET(stdOut.istream(), &readfds);
if (num2) FD_SET(stdErr.istream(), &readfds);
int n(mrw::max((num1?stdOut.istream():0),
(num2?stdErr.istream():0)));
timeval tm = {0, 10000};
int num = select(n, &readfds, 0, 0, &tm);
if (num<0) throw ExecutionFailedExc("select failed", *_cmd);
if (num==0 && res==pid) break; // process ended, no data left
// check and handle stdout
if (num>0 && FD_ISSET(stdOut.istream(), &readfds))
if ((num1=read(stdOut.istream(), buf, sizeof(buf)))>0)
_res += std::string(buf, num1);
else if (num1==-1 && (errno!=EINTR&&errno!=EAGAIN))
throw ExecutionFailedExc("readin stdout", *_cmd);
// check and handle stderr
if (num>0 && FD_ISSET(stdErr.istream(), &readfds))
if ((num2=read(stdErr.istream(), buf, sizeof(buf)))>0)
_err += std::string(buf, num2);
else if (num2==-1 && (errno!=EINTR&&errno!=EAGAIN))
throw ExecutionFailedExc("readin stderr", *_cmd);
} catch (...) {
if (exc) throw;
_success = false;
return *this;
}
} else { // child
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stdOut.close_in();
stdErr.close_in();
stdOut.connect_cout();
stdErr.connect_cerr();
execvp(_cmd->path(), _cmd->args());
exit(1); // execute failed
}
_success = true;
return *this;
}
mrw::Exec& mrw::Exec::execute(const std::string& input, bool exc)
throw(std::exception) {
/// @c input length must be smaller than @c SSIZE_MAX.
/// I'll only add support for longer strings upon request.
assert(input.size()<=SSIZE_MAX &&
"sdin input exeeds C library limit in mrw::Exec "
"please contact the author of the library");
/** This method calls @c fork, sets up a pipe connection to pass @c
stdin, @c stdout and @c stderr from the child process to the
parent process using mrw::Pipe and calls @c execvp to execute
the program. */
_success = false;
_res = _err = "";
mrw::Pipe stdIn(true), // child terminates if stdin is non-blocking
stdOut, stdErr;
if (!stdIn || !stdOut || !stdErr)
throw mrw::ExecutionFailedExc("cannot create pipe", *_cmd);
pid_t pid(fork());
if (pid<0) throw ExecutionFailedExc("cannot fork", *_cmd);
if (pid) { // parent
stdIn.close_in();
stdOut.close_out();
stdErr.close_out();
if (!stdIn || !stdOut || !stdErr)
throw ExecutionFailedExc("cannot close pipes", *_cmd);
ssize_t num0(-1), num1(-1), num2(-1);
std::string in(input);
fd_set writefds, readfds;
char buf[4096];
int res(0), s(0);
while (num0||num1||num2) try { // not all end of file
if (!res && (res=waitpid(pid, &s, WNOHANG)))
if (res!=pid || WIFEXITED(s)!=0 && WEXITSTATUS(s)!=0)
throw ExecutionFailedExc("execution failed", *_cmd);
// select...
FD_ZERO(&writefds);
FD_ZERO(&readfds);
if (num0) FD_SET(stdIn.ostream(), &writefds);
if (num1) FD_SET(stdOut.istream(), &readfds);
if (num2) FD_SET(stdErr.istream(), &readfds);
int n(mrw::max((num0?stdIn.ostream():0),
mrw::max((num1?stdOut.istream():0),
(num2?stdErr.istream():0))));
timeval tm = {0, 10000};
int num = select(n, &readfds, &writefds, 0, &tm);
if (num<0) throw ExecutionFailedExc("select failed", *_cmd);
if (num==0 && res==pid) break; // process ended, no data left
// check and handle stdin
if (num0 && num>0
&& FD_ISSET(stdIn.ostream(), &writefds))
if ((num0=write(stdIn.ostream(), in.c_str(), in.size()))>0) {
if ((unsigned int)num0<in.size())
in = in.substr(num0);
else if ((unsigned int)num0==in.size())
num0=0, stdIn.close_out();
} else if (num0==-1 && (errno!=EINTR&&errno!=EAGAIN))
throw ExecutionFailedExc("writing stdin", *_cmd);
// check and handle stdout
if (num>0 && FD_ISSET(stdOut.istream(), &readfds))
if ((num1=read(stdOut.istream(), buf, sizeof(buf)))>0)
_res += std::string(buf, num1);
else if (num1==-1 && (errno!=EINTR&&errno!=EAGAIN))
throw ExecutionFailedExc("readin stdout", *_cmd);
// check and handle stderr
if (num>0 && FD_ISSET(stdErr.istream(), &readfds))
if ((num2=read(stdErr.istream(), buf, sizeof(buf)))>0)
_err += std::string(buf, num2);
else if (num2==-1 && (errno!=EINTR&&errno!=EAGAIN))
throw ExecutionFailedExc("readin stderr", *_cmd);
} catch (...) {
if (exc) throw;
_success = false;
return *this;
}
} else { // child
stdIn.close_out();
stdOut.close_in();
stdErr.close_in();
stdIn.connect_cin();
stdOut.connect_cout(); // if cin is non blocking, child terminates here?!?
stdErr.connect_cerr();
execvp(_cmd->path(), _cmd->args());
exit(1); // execute failed
}
_success = true;
return *this;
}
mrw::Exec& mrw::Exec::operator>>(std::string& res) throw(std::exception) {
execute();
res += _res;
return *this;
}
mrw::Exec::operator std::string&() throw(std::exception) {
if (!_success) execute();
return _res;
}
mrw::Exec::operator bool() throw(std::bad_exception) {
return _success;
}
std::string& mrw::Exec::result() throw(std::exception) {
if (!_success) execute();
return _res;
}
std::string& mrw::Exec::error() throw(std::exception) {
if (!_success) execute();
return _err;
}
bool mrw::Exec::success() throw(std::bad_exception) {
return _success;
}