La Capture de la Sortie de a Engendré des Processus de la chaîne

Eddy Luten de réponse m'a conduit dans une bonne direction, mais la documentation MSDN (alors qu'élaborée) a eu quelques problèmes. Principalement, vous devez vous assurer que vous fermez toutes les poignées vous ne l'utilisez pas. Aussi, il a juste le code qu'il attend que l'utilisateur à comprendre.

Donc à la place, voici mon mur de code j'espère que les gens il suffit de comprendre 😀

#include <string>
#include <iostream>
#include <windows.h> 
#include <stdio.h>
#pragma warning( disable : 4800 ) //stupid warning about bool
#define BUFSIZE 4096
HANDLE g_hChildStd_OUT_Rd = NULL;
HANDLE g_hChildStd_OUT_Wr = NULL;
HANDLE g_hChildStd_ERR_Rd = NULL;
HANDLE g_hChildStd_ERR_Wr = NULL;
PROCESS_INFORMATION CreateChildProcess(void); 
void ReadFromPipe(PROCESS_INFORMATION); 
int main(int argc, char *argv[]){ 
SECURITY_ATTRIBUTES sa; 
printf("\n->Start of parent execution.\n");
//Set the bInheritHandle flag so pipe handles are inherited. 
sa.nLength = sizeof(SECURITY_ATTRIBUTES); 
sa.bInheritHandle = TRUE; 
sa.lpSecurityDescriptor = NULL; 
//Create a pipe for the child process's STDERR. 
if ( ! CreatePipe(&g_hChildStd_ERR_Rd, &g_hChildStd_ERR_Wr, &sa, 0) ) {
exit(1); 
}
//Ensure the read handle to the pipe for STDERR is not inherited.
if ( ! SetHandleInformation(g_hChildStd_ERR_Rd, HANDLE_FLAG_INHERIT, 0) ){
exit(1);
}
//Create a pipe for the child process's STDOUT. 
if ( ! CreatePipe(&g_hChildStd_OUT_Rd, &g_hChildStd_OUT_Wr, &sa, 0) ) {
exit(1);
}
//Ensure the read handle to the pipe for STDOUT is not inherited
if ( ! SetHandleInformation(g_hChildStd_OUT_Rd, HANDLE_FLAG_INHERIT, 0) ){
exit(1); 
}
//Create the child process. 
PROCESS_INFORMATION piProcInfo = CreateChildProcess();
//Read from pipe that is the standard output for child process. 
printf( "\n->Contents of child process STDOUT:\n\n", argv[1]);
ReadFromPipe(piProcInfo); 
printf("\n->End of parent execution.\n");
//The remaining open handles are cleaned up when this process terminates. 
//To avoid resource leaks in a larger application, 
//  close handles explicitly.
return 0; 
} 
//Create a child process that uses the previously created pipes
// for STDERR and STDOUT.
PROCESS_INFORMATION CreateChildProcess(){
//Set the text I want to run
char szCmdline[]="test --log_level=all --report_level=detailed";
PROCESS_INFORMATION piProcInfo; 
STARTUPINFO siStartInfo;
bool bSuccess = FALSE; 
//Set up members of the PROCESS_INFORMATION structure. 
ZeroMemory( &piProcInfo, sizeof(PROCESS_INFORMATION) );
//Set up members of the STARTUPINFO structure. 
//This structure specifies the STDERR and STDOUT handles for redirection.
ZeroMemory( &siStartInfo, sizeof(STARTUPINFO) );
siStartInfo.cb = sizeof(STARTUPINFO); 
siStartInfo.hStdError = g_hChildStd_ERR_Wr;
siStartInfo.hStdOutput = g_hChildStd_OUT_Wr;
siStartInfo.dwFlags |= STARTF_USESTDHANDLES;
//Create the child process. 
bSuccess = CreateProcess(NULL, 
szCmdline,     //command line 
NULL,          //process security attributes 
NULL,          //primary thread security attributes 
TRUE,          //handles are inherited 
0,             //creation flags 
NULL,          //use parent's environment 
NULL,          //use parent's current directory 
&siStartInfo,  //STARTUPINFO pointer 
&piProcInfo);  //receives PROCESS_INFORMATION
CloseHandle(g_hChildStd_ERR_Wr);
CloseHandle(g_hChildStd_OUT_Wr);
//If an error occurs, exit the application. 
if ( ! bSuccess ) {
exit(1);
}
return piProcInfo;
}
//Read output from the child process's pipe for STDOUT
//and write to the parent process's pipe for STDOUT. 
//Stop when there is no more data. 
void ReadFromPipe(PROCESS_INFORMATION piProcInfo) {
DWORD dwRead; 
CHAR chBuf[BUFSIZE];
bool bSuccess = FALSE;
std::string out = "", err = "";
for (;;) { 
bSuccess=ReadFile( g_hChildStd_OUT_Rd, chBuf, BUFSIZE, &dwRead, NULL);
if( ! bSuccess || dwRead == 0 ) break; 
std::string s(chBuf, dwRead);
out += s;
} 
dwRead = 0;
for (;;) { 
bSuccess=ReadFile( g_hChildStd_ERR_Rd, chBuf, BUFSIZE, &dwRead, NULL);
if( ! bSuccess || dwRead == 0 ) break; 
std::string s(chBuf, dwRead);
err += s;
} 
std::cout << "stdout:" << out << std::endl;
std::cout << "stderr:" << err << std::endl;
}

Shawn Blakesley code est bon de retravailler de Microsoft exemple de code, mais il a un peu un problème quand il est massive stdout et stderr entrelacés des flux qui sont hors de l'ordre. Et quelques poignées de fuite (qui est OK pour l'exemple de code). Ayant thread d'arrière-plan et PeekNamedPipe() appelle assure que le code se comportent de plus en plus semblables à POSIX appel système:

#include <windows.h> 
#include <stdio.h>
#include <malloc.h>
#ifdef __cplusplus
#define BEGIN_C extern "C" {
#define END_C } //extern "C"
#define null nullptr
#else
#define BEGIN_C
#define END_C
#define null ((void*)0)
#endif
BEGIN_C
int system_np(const char* command, int timeout_milliseconds, 
char* stdout_data, int stdout_data_size, 
char* stderr_data, int stderr_data_size, int* exit_code);
typedef struct system_np_s {
HANDLE child_stdout_read;
HANDLE child_stderr_read;
HANDLE reader;
PROCESS_INFORMATION pi;
const char* command;
char* stdout_data;
int   stdout_data_size;
char* stderr_data;
int   stderr_data_size;
int*  exit_code;
int   timeout; //timeout in milliseconds or -1 for INIFINTE
} system_np_t;
static char stdout_data[16 * 1024 * 1024];
static char stderr_data[16 * 1024 * 1024];
int main(int argc, char *argv[]) { 
int bytes = 1;
for (int i = 1; i < argc; i++) {
bytes += (int)strlen(argv[i]) + 1;
}
char* command = (char*)alloca(bytes);
command[0] = 0;
char* p = command;
for (int i = 1; i < argc; i++) {
int n = (int)strlen(argv[i]);
memcpy(p, argv[i], n); p += n;
*p = (i == argc - 1) ? 0x00 : 0x20; 
p++;
}
int exit_code = 0;
if (command[0] == 0) {
command = (char*)"cmd.exe /c \"dir /w /b\"";
}
int r = system_np(command, 100 * 1000, stdout_data, sizeof(stdout_data), stderr_data, sizeof(stderr_data), &exit_code);
if (r != 0) {
fprintf(stderr, "system_np failed: %d 0x%08x %s", r, r, strerror(r));
return r;
} else {
fwrite(stdout_data, strlen(stdout_data), 1, stdout);
fwrite(stderr_data, strlen(stderr_data), 1, stderr);
return exit_code;
}
}
static int peek_pipe(HANDLE pipe, char* data, int size) {         
char buffer[4 * 1024];
DWORD read = 0;  
DWORD available = 0;
bool b = PeekNamedPipe(pipe, null, sizeof(data), null, &available, null);
if (!b) {
return -1;
} else if (available > 0) {
int bytes = min(sizeof(buffer), available);
b = ReadFile(pipe, buffer, bytes, &read, null);
if (!b) {
return -1;
}
if (data != null && size > 0) {
int n = min(size - 1, (int)read);
memcpy(data, buffer, n);
data[n + 1] = 0; //always zero terminated
return n;
}
} 
return 0;
}
static DWORD WINAPI read_from_all_pipes_fully(void* p) {
system_np_t* system = (system_np_t*)p;
unsigned long long milliseconds = GetTickCount64(); //since boot time
char* out = system->stdout_data != null && system->stdout_data_size > 0 ? system->stdout_data : null;
char* err = system->stderr_data != null && system->stderr_data_size > 0 ? system->stderr_data : null;
int out_bytes = system->stdout_data != null && system->stdout_data_size > 0 ? system->stdout_data_size - 1 : 0;
int err_bytes = system->stderr_data != null && system->stderr_data_size > 0 ? system->stderr_data_size - 1 : 0;
for (;;) {
int read_stdout = peek_pipe(system->child_stdout_read, out, out_bytes);
if (read_stdout > 0 && out != null) { out += read_stdout; out_bytes -= read_stdout; } 
int read_stderr = peek_pipe(system->child_stderr_read, err, err_bytes);
if (read_stderr > 0 && err != null) { err += read_stderr; err_bytes -= read_stderr; } 
if (read_stdout < 0 && read_stderr < 0) { break; } //both pipes are closed
unsigned long long time_spent_in_milliseconds = GetTickCount64() - milliseconds;
if (system->timeout > 0 && time_spent_in_milliseconds > system->timeout) { break; }
if (read_stdout == 0 && read_stderr == 0) { //nothing has been read from both pipes
HANDLE handles[2] = {system->child_stdout_read, system->child_stderr_read};
WaitForMultipleObjects(2, handles, false, 1); //wait for at least 1 millisecond (more likely 16)
}
}
if (out != null) { *out = 0; }
if (err != null) { *err = 0; }
return 0;
}
static int create_child_process(system_np_t* system) {
SECURITY_ATTRIBUTES sa = {0}; 
sa.nLength = sizeof(SECURITY_ATTRIBUTES); 
sa.bInheritHandle = true; 
sa.lpSecurityDescriptor = null; 
HANDLE child_stdout_write = INVALID_HANDLE_VALUE;
HANDLE child_stderr_write = INVALID_HANDLE_VALUE;
if (!CreatePipe(&system->child_stderr_read, &child_stderr_write, &sa, 0) ) {
return GetLastError(); 
}
if (!SetHandleInformation(system->child_stderr_read, HANDLE_FLAG_INHERIT, 0) ){
return GetLastError(); 
}
if (!CreatePipe(&system->child_stdout_read, &child_stdout_write, &sa, 0) ) {
return GetLastError(); 
}
if (!SetHandleInformation(system->child_stdout_read, HANDLE_FLAG_INHERIT, 0) ){
return GetLastError(); 
}
//Set the text I want to run
STARTUPINFO siStartInfo = {0};
siStartInfo.cb = sizeof(STARTUPINFO); 
siStartInfo.hStdError = child_stderr_write;
siStartInfo.hStdOutput = child_stdout_write;
siStartInfo.dwFlags |= STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
siStartInfo.wShowWindow = SW_HIDE;
bool b = CreateProcessA(null, 
(char*)system->command,
null,               //process security attributes 
null,               //primary thread security attributes 
true,               //handles are inherited 
CREATE_NO_WINDOW,   //creation flags 
null,               //use parent's environment 
null,               //use parent's current directory 
&siStartInfo,       //STARTUPINFO pointer 
&system->pi);       //receives PROCESS_INFORMATION
int err = GetLastError();
CloseHandle(child_stderr_write);
CloseHandle(child_stdout_write);
if (!b) {
CloseHandle(system->child_stdout_read); system->child_stdout_read = INVALID_HANDLE_VALUE;
CloseHandle(system->child_stderr_read); system->child_stderr_read = INVALID_HANDLE_VALUE;
}
return b ? 0 : err;
}
int system_np(const char* command, int timeout_milliseconds, 
char* stdout_data, int stdout_data_size, 
char* stderr_data, int stderr_data_size, int* exit_code) {
system_np_t system = {0};
if (exit_code != null) { *exit_code = 0; }
if (stdout_data != null && stdout_data_size > 0) { stdout_data[0] = 0; }
if (stderr_data != null && stderr_data_size > 0) { stderr_data[0] = 0; }
system.timeout = timeout_milliseconds > 0 ? timeout_milliseconds : -1; 
system.command = command;
system.stdout_data = stdout_data;
system.stderr_data = stderr_data;
system.stdout_data_size = stdout_data_size;
system.stderr_data_size = stderr_data_size;
int r = create_child_process(&system);
if (r == 0) {
system.reader = CreateThread(null, 0, read_from_all_pipes_fully, &system, 0, null);
if (system.reader == null) { //in theory should rarely happen only when system super low on resources
r = GetLastError();
TerminateProcess(system.pi.hProcess, ECANCELED);
} else {
bool thread_done  = WaitForSingleObject(system.pi.hThread, timeout_milliseconds) == 0;
bool process_done = WaitForSingleObject(system.pi.hProcess, timeout_milliseconds) == 0;
if (!thread_done || !process_done) {
TerminateProcess(system.pi.hProcess, ETIME);
}
if (exit_code != null) {
GetExitCodeProcess(system.pi.hProcess, (DWORD*)exit_code);
}        
CloseHandle(system.pi.hThread);
CloseHandle(system.pi.hProcess);
CloseHandle(system.child_stdout_read); system.child_stdout_read = INVALID_HANDLE_VALUE;
CloseHandle(system.child_stderr_read); system.child_stderr_read = INVALID_HANDLE_VALUE;
WaitForSingleObject(system.reader, INFINITE); //join thread
CloseHandle(system.reader);
}
}
if (stdout_data != null && stdout_data_size > 0) { stdout_data[stdout_data_size - 1] = 0; }
if (stderr_data != null && stderr_data_size > 0) { stderr_data[stderr_data_size - 1] = 0; }
return r; 
} 
END_C