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Diffstat (limited to 'indra/llcommon/llprocess.h')
| -rw-r--r-- | indra/llcommon/llprocess.h | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/indra/llcommon/llprocess.h b/indra/llcommon/llprocess.h new file mode 100644 index 0000000000..0de033c15b --- /dev/null +++ b/indra/llcommon/llprocess.h @@ -0,0 +1,207 @@ +/** + * @file llprocess.h + * @brief Utility class for launching, terminating, and tracking child processes. + * + * $LicenseInfo:firstyear=2008&license=viewerlgpl$ + * Second Life Viewer Source Code + * Copyright (C) 2010, Linden Research, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License only. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA + * $/LicenseInfo$ + */ + +#ifndef LL_LLPROCESS_H +#define LL_LLPROCESS_H + +#include "llinitparam.h" +#include "llsdparam.h" +#include "apr_thread_proc.h" +#include <boost/shared_ptr.hpp> +#include <boost/noncopyable.hpp> +#include <iosfwd> // std::ostream + +#if LL_WINDOWS +#define WIN32_LEAN_AND_MEAN +#include <windows.h> // HANDLE (eye roll) +#elif LL_LINUX +#if defined(Status) +#undef Status +#endif +#endif + +class LLProcess; +/// LLProcess instances are created on the heap by static factory methods and +/// managed by ref-counted pointers. +typedef boost::shared_ptr<LLProcess> LLProcessPtr; + +/** + * LLProcess handles launching external processes with specified command line arguments. + * It also keeps track of whether the process is still running, and can kill it if required. +*/ +class LL_COMMON_API LLProcess: public boost::noncopyable +{ + LOG_CLASS(LLProcess); +public: + /// Param block definition + struct Params: public LLInitParam::Block<Params> + { + Params(): + executable("executable"), + args("args"), + cwd("cwd"), + autokill("autokill", true) + {} + + /// pathname of executable + Mandatory<std::string> executable; + /** + * zero or more additional command-line arguments. Arguments are + * passed through as exactly as we can manage, whitespace and all. + * @note On Windows we manage this by implicitly double-quoting each + * argument while assembling the command line. BUT if a given argument + * is already double-quoted, we don't double-quote it again. Try to + * avoid making use of this, though, as on Mac and Linux explicitly + * double-quoted args will be passed to the child process including + * the double quotes. + */ + Multiple<std::string> args; + /// current working directory, if need it changed + Optional<std::string> cwd; + /// implicitly kill process on destruction of LLProcess object + Optional<bool> autokill; + }; + typedef LLSDParamAdapter<Params> LLSDOrParams; + + /** + * Factory accepting either plain LLSD::Map or Params block. + * MAY RETURN DEFAULT-CONSTRUCTED LLProcessPtr if params invalid! + * + * Redundant with Params definition above? + * + * executable (required, string): executable pathname + * args (optional, string array): extra command-line arguments + * cwd (optional, string, dft no chdir): change to this directory before executing + * autokill (optional, bool, dft true): implicit kill() on ~LLProcess + */ + static LLProcessPtr create(const LLSDOrParams& params); + virtual ~LLProcess(); + + // isRunning() isn't const because, when child terminates, it sets stored + // Status + bool isRunning(void); + + /** + * State of child process + */ + enum state + { + UNSTARTED, ///< initial value, invisible to consumer + RUNNING, ///< child process launched + EXITED, ///< child process terminated voluntarily + KILLED ///< child process terminated involuntarily + }; + + /** + * Status info + */ + struct Status + { + Status(): + mState(UNSTARTED), + mData(0) + {} + + state mState; ///< @see state + /** + * - for mState == EXITED: mData is exit() code + * - for mState == KILLED: mData is signal number (Posix) + * - otherwise: mData is undefined + */ + int mData; + }; + + /// Status query + Status getStatus(); + /// English Status string query, for logging etc. + std::string getStatusString(); + /// English Status string query for previously-captured Status + std::string getStatusString(const Status& status); + /// static English Status string query + static std::string getStatusString(const std::string& desc, const Status& status); + + // Attempt to kill the process -- returns true if the process is no longer running when it returns. + // Note that even if this returns false, the process may exit some time after it's called. + bool kill(const std::string& who=""); + +#if LL_WINDOWS + typedef int id; ///< as returned by getProcessID() + typedef HANDLE handle; ///< as returned by getProcessHandle() +#else + typedef pid_t id; + typedef pid_t handle; +#endif + /** + * Get an int-like id value. This is primarily intended for a human reader + * to differentiate processes. + */ + id getProcessID() const; + /** + * Get a "handle" of a kind that you might pass to platform-specific API + * functions to engage features not directly supported by LLProcess. + */ + handle getProcessHandle() const; + + /** + * Test if a process (@c handle obtained from getProcessHandle()) is still + * running. Return same nonzero @c handle value if still running, else + * zero, so you can test it like a bool. But if you want to update a + * stored variable as a side effect, you can write code like this: + * @code + * hchild = LLProcess::isRunning(hchild); + * @endcode + * @note This method is intended as a unit-test hook, not as the first of + * a whole set of operations supported on freestanding @c handle values. + * New functionality should be added as nonstatic members operating on + * the same data as getProcessHandle(). + * + * In particular, if child termination is detected by static isRunning() + * rather than by nonstatic isRunning(), the LLProcess object won't be + * aware of the child's changed status and may encounter OS errors trying + * to obtain it. static isRunning() is only intended for after the + * launching LLProcess object has been destroyed. + */ + static handle isRunning(handle, const std::string& desc=""); + +private: + /// constructor is private: use create() instead + LLProcess(const LLSDOrParams& params); + void autokill(); + // Classic-C-style APR callback + static void status_callback(int reason, void* data, int status); + // Object-oriented callback + void handle_status(int reason, int status); + + std::string mDesc; + apr_proc_t mProcess; + bool mAutokill; + Status mStatus; +}; + +/// for logging +LL_COMMON_API std::ostream& operator<<(std::ostream&, const LLProcess::Params&); + +#endif // LL_LLPROCESS_H |