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Merge pull request git-for-windows#1170 from dscho/mingw-kill-process
Handle Ctrl+C in Git Bash nicely
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,164 @@ | ||
| #ifndef EXIT_PROCESS_H | ||
| #define EXIT_PROCESS_H | ||
|
|
||
| /* | ||
| * This file contains functions to terminate a Win32 process, as gently as | ||
| * possible. | ||
| * | ||
| * At first, we will attempt to inject a thread that calls ExitProcess(). If | ||
| * that fails, we will fall back to terminating the entire process tree. | ||
| * | ||
| * For simplicity, these functions are marked as file-local. | ||
| */ | ||
|
|
||
| #include <tlhelp32.h> | ||
|
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||
| /* | ||
| * Terminates the process corresponding to the process ID and all of its | ||
| * directly and indirectly spawned subprocesses. | ||
| * | ||
| * This way of terminating the processes is not gentle: the processes get | ||
| * no chance of cleaning up after themselves (closing file handles, removing | ||
| * .lock files, terminating spawned processes (if any), etc). | ||
| */ | ||
| static int terminate_process_tree(HANDLE main_process, int exit_status) | ||
| { | ||
| HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0); | ||
| PROCESSENTRY32 entry; | ||
| DWORD pids[16384]; | ||
| int max_len = sizeof(pids) / sizeof(*pids), i, len, ret = 0; | ||
| pid_t pid = GetProcessId(main_process); | ||
|
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| pids[0] = (DWORD)pid; | ||
| len = 1; | ||
|
|
||
| /* | ||
| * Even if Process32First()/Process32Next() seem to traverse the | ||
| * processes in topological order (i.e. parent processes before | ||
| * child processes), there is nothing in the Win32 API documentation | ||
| * suggesting that this is guaranteed. | ||
| * | ||
| * Therefore, run through them at least twice and stop when no more | ||
| * process IDs were added to the list. | ||
| */ | ||
| for (;;) { | ||
| int orig_len = len; | ||
|
|
||
| memset(&entry, 0, sizeof(entry)); | ||
| entry.dwSize = sizeof(entry); | ||
|
|
||
| if (!Process32First(snapshot, &entry)) | ||
| break; | ||
|
|
||
| do { | ||
| for (i = len - 1; i >= 0; i--) { | ||
| if (pids[i] == entry.th32ProcessID) | ||
| break; | ||
| if (pids[i] == entry.th32ParentProcessID) | ||
| pids[len++] = entry.th32ProcessID; | ||
| } | ||
| } while (len < max_len && Process32Next(snapshot, &entry)); | ||
|
|
||
| if (orig_len == len || len >= max_len) | ||
| break; | ||
| } | ||
|
|
||
| for (i = len - 1; i > 0; i--) { | ||
| HANDLE process = OpenProcess(PROCESS_TERMINATE, FALSE, pids[i]); | ||
|
|
||
| if (process) { | ||
| if (!TerminateProcess(process, exit_status)) | ||
| ret = -1; | ||
| CloseHandle(process); | ||
| } | ||
| } | ||
| if (!TerminateProcess(main_process, exit_status)) | ||
| ret = -1; | ||
| CloseHandle(main_process); | ||
|
|
||
| return ret; | ||
| } | ||
|
|
||
| /** | ||
| * Determine whether a process runs in the same architecture as the current | ||
| * one. That test is required before we assume that GetProcAddress() returns | ||
| * a valid address *for the target process*. | ||
| */ | ||
| static inline int process_architecture_matches_current(HANDLE process) | ||
| { | ||
| static BOOL current_is_wow = -1; | ||
| BOOL is_wow; | ||
|
|
||
| if (current_is_wow == -1 && | ||
| !IsWow64Process (GetCurrentProcess(), ¤t_is_wow)) | ||
| current_is_wow = -2; | ||
| if (current_is_wow == -2) | ||
| return 0; /* could not determine current process' WoW-ness */ | ||
| if (!IsWow64Process (process, &is_wow)) | ||
| return 0; /* cannot determine */ | ||
| return is_wow == current_is_wow; | ||
| } | ||
|
|
||
| /** | ||
| * Inject a thread into the given process that runs ExitProcess(). | ||
| * | ||
| * Note: as kernel32.dll is loaded before any process, the other process and | ||
| * this process will have ExitProcess() at the same address. | ||
| * | ||
| * This function expects the process handle to have the access rights for | ||
| * CreateRemoteThread(): PROCESS_CREATE_THREAD, PROCESS_QUERY_INFORMATION, | ||
| * PROCESS_VM_OPERATION, PROCESS_VM_WRITE, and PROCESS_VM_READ. | ||
| * | ||
| * The idea comes from the Dr Dobb's article "A Safer Alternative to | ||
| * TerminateProcess()" by Andrew Tucker (July 1, 1999), | ||
| * http://www.drdobbs.com/a-safer-alternative-to-terminateprocess/184416547 | ||
| * | ||
| * If this method fails, we fall back to running terminate_process_tree(). | ||
| */ | ||
| static int exit_process(HANDLE process, int exit_code) | ||
| { | ||
| DWORD code; | ||
|
|
||
| if (GetExitCodeProcess(process, &code) && code == STILL_ACTIVE) { | ||
| static int initialized; | ||
| static LPTHREAD_START_ROUTINE exit_process_address; | ||
| PVOID arg = (PVOID)(intptr_t)exit_code; | ||
| DWORD thread_id; | ||
| HANDLE thread = NULL; | ||
|
|
||
| if (!initialized) { | ||
| HINSTANCE kernel32 = GetModuleHandle("kernel32"); | ||
| if (!kernel32) | ||
| die("BUG: cannot find kernel32"); | ||
| exit_process_address = (LPTHREAD_START_ROUTINE) | ||
| GetProcAddress(kernel32, "ExitProcess"); | ||
| initialized = 1; | ||
| } | ||
| if (!exit_process_address || | ||
| !process_architecture_matches_current(process)) | ||
| return terminate_process_tree(process, exit_code); | ||
|
|
||
| thread = CreateRemoteThread(process, NULL, 0, | ||
| exit_process_address, | ||
| arg, 0, &thread_id); | ||
| if (thread) { | ||
| CloseHandle(thread); | ||
| /* | ||
| * If the process survives for 10 seconds (a completely | ||
| * arbitrary value picked from thin air), fall back to | ||
| * killing the process tree via TerminateProcess(). | ||
| */ | ||
| if (WaitForSingleObject(process, 10000) == | ||
| WAIT_OBJECT_0) { | ||
| CloseHandle(process); | ||
| return 0; | ||
| } | ||
| } | ||
|
|
||
| return terminate_process_tree(process, exit_code); | ||
| } | ||
|
|
||
| return 0; | ||
| } | ||
|
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||
| #endif |