i'm traing to do 2 process that do this:
Process A (the client) : - It opens a temporary file for writing (use GetTempFileName to obtain a unique file name). - It starts Process B passing as argument the name of the file. - It reads from standard input strings of characters, and it writes those strings on the intermediate file. Use string of constant length (e.g., #define MAX_LEN 100). - It stops reading strings from standard input when it receives an end-of-file (ctrl-Z). - Before terminating, it writes the string ".end" as last line of the file.
Process B (the server) works as follows: - It opens the intermediate file for reading. - It reads lines as soon as they are available, and it prints them out on standard output.
- Process A keeps the file open, and it always locks the next part of the file before unlocking the previous part.
- Process B runs in parallel, and it reads a shared file, waiting to have access to single lines to read them.
but seams that the ReadFile on process B do not wait until the fileLock is removed so it terminate befor the first line is inserted
process A:
#include <windows.h>
#include <process.h>
#include <tchar.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <io.h>
#define MAX_LEN 100
int _tmain(int argc, LPTSTR argv[]){
TCHAR tmpFileName[MAX_PATH];
TCHAR tmppath[MAX_PATH];
TCHAR moment[MAX_PATH];
TCHAR command[MAX_PATH + 256];
UINT uRetVal = 0;
HANDLE bufferW,next;
DWORD n;
PROCESS_INFORMATION piS;
STARTUPINFO siS;
TCHAR buffer[MAX_LEN];
int i=0;
OVERLAPPED ov = { 0, 0, 0, 0, NULL };
LARGE_INTEGER FilePos;
ZeroMemory(&siS, sizeof(siS));
siS.cb = sizeof(siS);
ZeroMemory(&piS, sizeof(piS));
uRetVal = GetTempFileName(_T("."), // directory for tmp files
_T(""), // temp file name prefix
0, // create unique name
tmpFileName); // buffer for name
if (uRetVal == 0)
{
_tprintf("\n errore apertura temp file");
return (3);
}
GetCurrentDirectory(MAX_PATH, moment);
//_stprintf(tmppath, "%s\\ %s",moment,tmpFileName);
_tprintf("\n CLIENT PATH %s \n",moment);
//_stprintf(command,"%s %s","C:\\Users\\zio gianni\\Documents\\Visual Studio 2013\\Projects\\lab11server\\Debug\\lab11server.exe",tmpFileName);
_stprintf(command, "%s %s", "server.exe", tmpFileName);
bufferW = CreateFile(tmpFileName, GENERIC_WRITE, FILE_SHARE_WRITE | FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
next = CreateFile(tmpFileName, GENERIC_WRITE, FILE_SHARE_WRITE | FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (next == INVALID_HANDLE_VALUE) {
_tprintf(_T("Cannot open client file. Error: %x\n"),
GetLastError());
_tprintf(" \n Nome File: %s\n", "./prova.bin");
return 2;
}
if (bufferW == INVALID_HANDLE_VALUE) {
_tprintf(_T("Cannot open client file. Error: %x\n"),
GetLastError());
_tprintf(" \n Nome File: %s\n", "./prova.bin");
return 2;
}
FilePos.QuadPart = i*MAX_LEN * sizeof (TCHAR);
ov.Offset = FilePos.LowPart;
ov.OffsetHigh = FilePos.HighPart;
ov.hEvent = 0;
LockFileEx(bufferW, LOCKFILE_EXCLUSIVE_LOCK, 0, FilePos.LowPart, FilePos.HighPart, &ov);
printf("file bloccato avvio server con comand: %s\n", command);
if (!CreateProcess(NULL, // No module name (use command line)
command, // Command line
NULL, // Process handle not inheritable
NULL, // Thread handle not inheritable
TRUE, // Set handle inheritance to FALSE
0, // No creation flags
NULL, // Use parent's environment block
NULL, // Use parent's starting directory
&siS, // Pointer to STARTUPINFO structure
&piS) // Pointer to PROCESS_INFORMATION structure
)
{
printf("CreateProcess failed (%d).\n", GetLastError());
return -5;
}
while (TRUE){
scanf("%s",buffer);
if (strcmp(buffer, "EOF")==0){
break;
}
WriteFile(bufferW, buffer, MAX_LEN*sizeof(TCHAR), &n, NULL);
FilePos.QuadPart =(i+1)* MAX_LEN * sizeof (TCHAR);
ov.Offset = FilePos.LowPart;
ov.OffsetHigh = FilePos.HighPart;
ov.hEvent = 0;
if (i % 2 == 0){
LockFile(next, LOCKFILE_EXCLUSIVE_LOCK, 0, FilePos.LowPart, FilePos.HighPart, &ov);
FilePos.QuadPart = (i )* MAX_LEN * sizeof (TCHAR);
ov.Offset = FilePos.LowPart;
ov.OffsetHigh = FilePos.HighPart;
ov.hEvent = 0;
UnlockFile(bufferW, 0, 0, 0, &ov);
}
else{
LockFile(bufferW, LOCKFILE_EXCLUSIVE_LOCK, 0, FilePos.LowPart, FilePos.HighPart, &ov);
FilePos.QuadPart = (i )* MAX_LEN * sizeof (TCHAR);
ov.Offset = FilePos.LowPart;
ov.OffsetHigh = FilePos.HighPart;
ov.hEvent = 0;
UnlockFile(next, 0, 0, 0, &ov);
}
i++;
}
sprintf(buffer, ".end");
WriteFile(bufferW, buffer, MAX_LEN*sizeof(TCHAR), &n ,NULL);
if (i % 2 == 0){
FilePos.QuadPart = (i)* MAX_LEN * sizeof (TCHAR);
ov.Offset = FilePos.LowPart;
ov.OffsetHigh = FilePos.HighPart;
ov.hEvent = 0;
UnlockFile(bufferW, 0, FilePos.LowPart, FilePos.HighPart, &ov);
}
else{
FilePos.QuadPart = (i)* MAX_LEN * sizeof (TCHAR);
ov.Offset = FilePos.LowPart;
ov.OffsetHigh = FilePos.HighPart;
ov.hEvent = 0;
UnlockFile(next, 0, FilePos.LowPart, FilePos.HighPart, &ov);
}
// Wait until child process exits.
WaitForSingleObject(piS.hProcess, INFINITE);
// Close process and thread handles.
CloseHandle(piS.hProcess);
CloseHandle(piS.hThread);
return 0;
}
process B:
#include <windows.h>
#include <process.h>
#include <tchar.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <io.h>
#define MAX_LEN 100
int _tmain(int argc, LPTSTR argv[]){
HANDLE read;
DWORD n;
int i = 0;
TCHAR buffer[MAX_LEN], path[MAX_LEN];
OVERLAPPED ov = { 0, 0, 0, 0, NULL };
LARGE_INTEGER FilePos;
read = CreateFile(argv[1], GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (read == INVALID_HANDLE_VALUE) {
_tprintf(_T("Cannot open input file. Error: %x\n"),
GetLastError());
_tprintf(" \n Nome File: %s\n", argv[1]);
return 2;
}
_tprintf(" \n Nome File APERTO: %s\n", argv[1]);
GetCurrentDirectory(MAX_LEN,path);
_tprintf(" \n path server: %s\n%s\n", path,argv[1]);
while (ReadFile(read, buffer, MAX_LEN*sizeof(TCHAR), &n, &ov) && n>0 ){
if (n == 0){
fprintf(stderr,"error readfle\n");
return -5;
}
if (strncmp(buffer, ".end", 4) == 0){
_tprintf(" \n STAMPA SERVER: esco\n");
break;
}
_tprintf(" \n STAMPA SERVER: %s\n", buffer);
}
if (n == 0){
fprintf(stderr, "error readfle\n");
return -5;
}
_tprintf("\n END SERVER");
return 0;
}
ReadFilewill return 0 if there's no data left to read in the file, and you're exiting your loop at that point. – Jonathan PotterTCHARfor your data buffer, but not using TCHAR APIs to receive input data into that buffer, and output data from that buffer? You do realize that this code will not even compile if you enable Unicode, don't you? And why are you sending the entire buffer instead of only the characters that the user actually entered? – Remy Lebeau