I have the following c code which I took from the first answer to this question, I am compiling it with C89 in VS2008 so I made a couple of changes for the code to work it properly, it compiles just fine, but it's not able to create process after creating the namedpipe successfully (CreateProcessA is not working) returning always error 2 and printing the message in the panic function.
The program that I am trying to run in the CreateProcessA can be downloaded here, and I normally run it and use it as follows:
> C:\qhichwa>cmd.exe /c "C:\qhichwa\flookup.exe -bx C:\qhichwa\qhichwa.fst"
wasi <user writes wasi>
wasi <program responds printing wasi>
hola <user writes hola>
+ ? <program responds printing + ?>
<pres ctrl + c to terminate program>
> C:\qhichwa>
The lines between < comments > are just comments.
what are the corrections needed in order to to create the named pipe successfully?
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
// name of our glorious pipe
#define PIPE_NAME L"\\\\.\\pipe\\whatever" // bloody unicode string
// exit on fatal error
void panic(const char * msg)
{
int err = GetLastError();
fprintf(stderr, "***PANIC*** %s\n", msg);
printf("In the child thread: Last Error is %lu\n", err);
exit(-1);
}
// father process
void father(const char * own_name) // name of our own executable to launch a copy of ourselve
{
printf("Father process starting\n");
// create a monodirectional father->child named pipe
HANDLE pipe = CreateNamedPipe(
PIPE_NAME, // name of the pipe
PIPE_ACCESS_OUTBOUND, // send only
PIPE_TYPE_BYTE, // send data as a byte stream
1, // only one instance
0, 0, 0, NULL); // default junk
if (pipe == INVALID_HANDLE_VALUE) panic("could not create pipe 1");
// spawn child process
{
STARTUPINFOA si;
PROCESS_INFORMATION pi;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
if (!CreateProcessA( // using ASCII variant to be compatible with argv
"cmd.exe", // executable name (ourself)
"/c \"C:\\qhichwa\\flookup.exe -bx C:\\qhichwa\\qhichwa.fst\"", // command line. This will be seen as argv[0]
NULL, NULL, FALSE, // default junk
CREATE_NEW_CONSOLE, // launch in another console window
NULL, NULL, // more junk
&si, &pi)) // final useless junk
panic("could not create child process 2");
}
// connect to child process
BOOL result = ConnectNamedPipe(pipe, NULL);
if (!result) panic("could not connect to child process");
// talk to child
for (;;)
{
// read an input line
char line[100];
printf("Say something >");
if (fgets(line, sizeof(line), stdin) == NULL)
panic("could not read from standard input");
// exit on an empty line
if (!strcmp(line, "\n")) break;
// send the line to the child
DWORD written = 0;
if (!WriteFile(
pipe,
line, // sent data
strlen(line), // data length
&written, // bytes actually written
NULL))
panic("could not write to pipe");
}
// close the pipe
CloseHandle(pipe);
}
void child(void)
{
printf("Child process starting\n");
// retrieve communication pipe
HANDLE pipe = CreateFile(
PIPE_NAME, // name of the pipe
GENERIC_READ, // read ONLY access (or else the call will fail)
0, NULL, // junk
OPEN_EXISTING, // opens existing pipe
0, NULL); // more junk
if (pipe == INVALID_HANDLE_VALUE) panic("could not connect to the pipe");
// read father's input
for (;;)
{
char buffer[80];
DWORD read = 0;
if (!ReadFile(
pipe,
buffer, // read data
sizeof(buffer)-1, // max length (leave room for terminator)
&read, // bytes actually read
NULL))
break; // exit if the pipe has closed
// display what our father said
buffer[read] = '\0'; // make sure what we just read will be displayable as a string
printf("Father said: %s", buffer);
}
// close pipe
CloseHandle(pipe);
}
int main(int argc, char *argv[])
{
// wait for a <return> keypress on exit
atexit(getchar);
father(argv[0]);
// decide whether we are the father or the child
//if (!strcmp(argv[0], "child")) child();
//else father(argv[0]);
printf("Done\n");
return 0;
}
