#include <stdio.h>
#include <iostream>
#include <Windows.h>
#include <C:\Program Files\Microsoft MPI\Inc\mpi.h>
using namespace std;
#define BUFSIZE 128
int main (int argc, char *argv[])
{
int err;
int rank;
int size;
double start_time = 0.0;
double end_time;
MPI_Comm comm = MPI_COMM_WORLD;
MPI_File file;
char cbuf[BUFSIZE];
for(int i = 0; i < BUFSIZE; i++)
{
cbuf[i] = 'a' + i;
}
if(err = MPI_Init(&argc, &argv))
{
printf("%s \n", "Error! MPI is halted!");
MPI_Abort(comm, err);
}
MPI_Comm_size(comm, &size);
MPI_Comm_rank(comm, &rank);
if(rank == 0)
{
start_time = MPI_Wtime();
}
err = MPI_File_open(comm, "testfile", MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &file);
if(err != MPI_SUCCESS)
{
printf("Error %d! Can't open the file!\n", err);
MPI_Abort(comm, err);
return EXIT_FAILURE;
}
err = MPI_File_set_view(file, (MPI_Offset) (rank * BUFSIZE * sizeof(char)), MPI_CHAR, MPI_CHAR, "native", MPI_INFO_NULL);
if(err != MPI_SUCCESS)
{
printf("%s \n", "Error! Can't set the view!");
MPI_Abort(comm, err);
return EXIT_FAILURE;
}
err = MPI_File_write(file, cbuf, BUFSIZE, MPI_CHAR, MPI_STATUSES_IGNORE);
if(err != MPI_SUCCESS)
{
printf("%s \n", "Error! Problems with writing!");
MPI_Abort(comm, err);
return EXIT_FAILURE;
}
MPI_File_close(&file);
if(rank == 0)
{
end_time = MPI_Wtime();
printf("Time elapsed : %f seconds", (end_time - start_time) * 1000);
}
MPI_Finalize();
return EXIT_SUCCESS;
}
I'm trying to write some symbols to a file with MPI. When I do that, I get an errorcode of 288 and the file can't be opened. I used command line: mpiexec -n 10 myapp.exe. I was searching for the errorcode but didn't find anything at all.
Go one step further. Your error code doesn't mean anything by itself. But, you can feed that code to MPI_Error_string and get something more human readable. I have this function in every MPI-IO code I write:
static void handle_error(int errcode, char *str)
{
char msg[MPI_MAX_ERROR_STRING];
int resultlen;
MPI_Error_string(errcode, msg, &resultlen);
fprintf(stderr, "%s: %s\n", str, msg);
MPI_Abort(MPI_COMM_WORLD, 1);
}
And then define this macro:
#define MPI_CHECK(fn) { int errcode; errcode = (fn);\
if (errcode != MPI_SUCCESS) handle_error (errcode, #fn ); }
So I can call routines like this:
CHECK(MPI_File_open(comm, "testfile",
MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &file) );
Related
I'm trying to use a sqlite memory db ala "file:zmem?mode=memory&cache=shared" with multiple threads. To test this i have the following code which is not multi threaded, but just opens a second connection to the same memory db to read the results. Unfortunately i'm not able to find any working code samples on either sqlite.org or any other site on the internet.
I have the following C99 test code which works until another connection tries to access what the first connection created.
#include <sqlite3.h>
#include <stdio.h>
int exec(sqlite3 *db, char* sql) {
sqlite3_stmt *stmt;
int ret;
do {
ret = sqlite3_prepare_v2(db, sql, -1, &stmt, 0);
if (ret != SQLITE_OK) {
printf("prep error: %s", sqlite3_errmsg(db));
break;
}
ret = sqlite3_step(stmt);
if (ret != SQLITE_DONE) {
printf("step error: %s", sqlite3_errmsg(db));
break;
}
ret = SQLITE_OK;
} while(0);
sqlite3_finalize(stmt);
return ret;
}
sqlite3* getCon(char *name) {
sqlite3 *db = 0;
int flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
SQLITE_OPEN_NOMUTEX | SQLITE_OPEN_MEMORY | SQLITE_OPEN_SHAREDCACHE;
int ret = sqlite3_open_v2(name, &db, flags, 0);
if (ret != SQLITE_OK) {
printf("no open");
}
return db;
}
void query(sqlite3 *db) {
sqlite3_stmt *stmt = 0;
do {
int ret = sqlite3_prepare_v2(db, "SELECT * FROM MyTable", -1, &stmt, 0);
if (ret != SQLITE_OK) {
printf("prep error: %s\n", sqlite3_errmsg(db));
break;
}
while ((ret = sqlite3_step(stmt)) == SQLITE_ROW) {
char *name = (char *) sqlite3_column_text(stmt, 0);
printf("%s\n", name);
}
if (ret != SQLITE_DONE) {
printf("step error: %s\n", sqlite3_errmsg(db));
}
} while(0);
sqlite3_finalize(stmt);
}
int main() {
sqlite3 *db = 0, *db2 = 0;
char *label = "zmem";
char bf[64];
char *buf = &bf[0];
int ret, i;
do {
db = getCon(label);
if (!db) break;
printf("connected\n");
ret = exec(db, "CREATE TABLE MyTable (test VARCHAR(255));");
if (ret != SQLITE_OK) break;
for (i = 1; i <= 3; i++) {
sprintf(buf,"insert into MyTable (test) values('Hello Row %d')", i);
ret = exec(db, buf);
if (ret != SQLITE_OK) break;
}
query(db);
db2 = getCon(label);
if (!db2) break;
printf("connected 2\n");
query(db2);
} while(0);
if (db) sqlite3_close(db);
if (db2) sqlite3_close(db2);
}
When i run this code it produces the following for me
connected
Hello Row 1
Hello Row 2
Hello Row 3
connected 2
prep error: no such table: MyTable
Could someone clue me in on how to properly do this?
I am trying to use serial communication in Raspberry Pi. I found this link. I made only one change in the code and increase the buffer value to 30. Here my edited code:-
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
int main(int argc, char* argv[]) {
struct termios serial;
char* str = "Hello";
char buffer[30];
if (argc == 1) {
printf("Usage: %s [device]\n\n", argv[0]);
return -1;
}
printf("Opening %s\n", argv[1]);
int fd = open(argv[1], O_RDWR | O_NOCTTY | O_NDELAY);
if (fd == -1) {
perror(argv[1]);
return -1;
}
if (tcgetattr(fd, &serial) < 0) {
perror("Getting configuration");
return -1;
}
// Set up Serial Configuration
serial.c_iflag = 0;
serial.c_iflag = 0;
serial.c_oflag = 0;
serial.c_lflag = 0;
serial.c_cflag = 0;
serial.c_cc[VMIN] = 0;
serial.c_cc[VTIME] = 0;
serial.c_cflag = B115200 | CS8 | CREAD;
tcsetattr(fd, TCSANOW, &serial); // Apply configuration
// Attempt to send and receive
printf("Sending: %s\n", str);
//int wcount = write(fd, &str, strlen(str));
int wcount = write(fd, str, strlen(str));
if (wcount < 0) {
perror("Write");
return -1;
}
else {
printf("Sent %d characters\n", wcount);
}
// int rcount = read(fd, &buffer, sizeof(buffer));
int rcount = read(fd, buffer, sizeof(buffer));
if (rcount < 0) {
perror("Read");
return -1;
}
else {
printf("Received %d characters\n", rcount);
}
buffer[rcount] = '\0';
printf("Received: %s\n", buffer);
close(fd);
}
I short Rx and Tx pin and run this code. I should receive "Hello" but I am getting this:-
Received: pi#raspberrypi:~$ Hello
So, it is clear that I am receiving "Hello" but additionally I am automatically transmitting
pi#raspberrypi:~$
So, please tell me I to stop transmitting my user name.
I'm writing a code for extraction of peer credential by the server process connected through ipc using domain sockets to the client process. There is no error in the code but while running it I don't get the euid and gid of the peer process.
Code for server process is:
#include <stdio.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
//#include<ucred.h>
#define SCM_CREDENTIALS
# define UNIX_PATH_MAX 100
int getpeereid(int connection_fd,uid_t euid,gid_t gid)
{
struct ucred cred;
socklen_t len = sizeof(cred);
if (getsockopt(connection_fd, SOL_SOCKET, SO_PEERCRED, &cred, &len) < 0)
return (-1);
euid =cred.uid;
gid = cred.gid;
//int passcred=1;
//setsockopt(connection_fd,SOL_SOCKET,SO_PASSCRED,(void *)&passcred,sizeof(passcred));
printf("effective user id", euid);
printf("effective group id",gid);
return 0;
}
int connection_handler(int connection_fd)
{
int nbytes;
char buffer[1024];
char msg[256];
//while(cont=recv(connection_fd,buffer,sizeof(buffer),0)>0)
//{
//write(1,buffer,cont)
nbytes = read(connection_fd, buffer, 256);
buffer[nbytes] = 0;
printf("MESSAGE FROM CLIENT: %s\n", buffer);
printf("enter the message");
scanf("%s",msg);
nbytes = snprintf(buffer, 256,msg);
write(connection_fd, buffer, nbytes);
//}
close(connection_fd);
return 0;
}
int main(void)
{
struct sockaddr_un address;
int socket_fd, connection_fd,res;
socklen_t address_length;
pid_t child;
uid_t eid;
gid_t gid;
socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
if(socket_fd < 0)
{
printf("socket() failed\n");
return 1;
}
printf("socket created\n");
unlink("./demo_socket");
/* start with a clean address structure */
memset(&address, 0, sizeof(struct sockaddr_un));
address.sun_family = AF_UNIX;
snprintf(address.sun_path, UNIX_PATH_MAX, "./demo_socket");
if(bind(socket_fd,
(struct sockaddr *) &address,
sizeof(struct sockaddr_un)) != 0)
{
printf("bind() failed\n");
return 1;
}
if(listen(socket_fd, 5) != 0)
{
printf("listen() failed\n");
return 1;
}
while((connection_fd = accept(socket_fd,
(struct sockaddr *) &address,
&address_length)) > -1)
{
// get the credentials
res=getpeereid(connection_fd,geteuid(),getgid());
if (res==0)
{
//if(res==0)
//{
child = fork();
if(child == 0)
{
/* now inside newly created connection handling process */
return connection_handler(connection_fd);
}
}
/* still inside server process */
close(connection_fd);
//}
}
close(socket_fd);
unlink("./demo_socket");
return 0;
}
the code for client
#include <stdio.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <string.h>
#define UNIX_PATH_MAX 100
int connection_handler(int socket_fd)
{
int nbytes;
char buffer[1024];
char mesg[256];
printf("enter the message");
scanf("%s",mesg);
//printf("message is %s",mesg);
nbytes = snprintf(buffer, 256,mesg);
//fgets(buffer,256,mesg);
//i=atoi(mesg);
write(socket_fd,buffer,nbytes);
//send(socket_fd,mesg,sizeof(mesg),0);
}
//nbytes = read(socket_fd, buffer, 256);
//buffer[nbytes] = 0;
//printf("MESSAGE FROM SERVER: %s\n", buffer);
//}
int main(void)
{
struct sockaddr_un address;
int socket_fd, nbytes,i;
pid_t child;
char buffer[256];
//char mesg[100];
socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
if(socket_fd < 0)
{
printf("socket() failed\n");
return 1;
}
printf("socket created\n");
/* start with a clean address structure */
memset(&address, 0, sizeof(struct sockaddr_un));
address.sun_family = AF_UNIX;
snprintf(address.sun_path, UNIX_PATH_MAX, "./demo_socket");
if(connect(socket_fd,
(struct sockaddr *) &address,
sizeof(struct sockaddr_un)) != 0)
{
printf("connect() failed\n");
return 1;
}
child=fork();
while(child==0)
{
return connection_handler(socket_fd);
//printf("connection established\n");
//printf("enter the message");
//scanf("%s",mesg);
//printf("message is %s",mesg);
//bytes = snprintf(buffer, 256,mesg);
//fgets(buffer,256,mesg);
//i=atoi(mesg);
//write(socket_fd,buffer,nbytes);
//send(socket_fd,mesg,sizeof(mesg),0);
}
nbytes = read(socket_fd, buffer, 256);
buffer[nbytes] = 0;
printf("MESSAGE FROM SERVER: %s\n", buffer);
close(socket_fd);
return 0;
}
See http://www.thomasstover.com/uds.html for good overview.
If the server is Linux, the main problem is missing _GNU_SOURCE. Full patch below, it has a few minor changes just to get rid of gcc -Wall -Werror -pedantic -std=c99 errors and warnings.
--- server.c.orig 2014-12-06 13:23:09.138472871 +0200
+++ server.c 2014-12-06 13:21:31.962475754 +0200
## -1,3 +1,4 ##
+#define _GNU_SOURCE
#include <stdio.h>
#include <sys/socket.h>
#include <sys/un.h>
## -5,7 +6,6 ##
#include <unistd.h>
#include <string.h>
//#include<ucred.h>
-#define SCM_CREDENTIALS
# define UNIX_PATH_MAX 100
int getpeereid(int connection_fd,uid_t euid,gid_t gid)
## -20,8 +20,8 ##
//int passcred=1;
//setsockopt(connection_fd,SOL_SOCKET,SO_PASSCRED,(void *)&passcred,sizeof(passcred));
-printf("effective user id", euid);
-printf("effective group id",gid);
+printf("effective user id %d", euid);
+printf("effective group id %d",gid);
return 0;
}
## -40,7 +40,7 ##
printf("MESSAGE FROM CLIENT: %s\n", buffer);
printf("enter the message");
scanf("%s",msg);
-nbytes = snprintf(buffer, 256,msg);
+nbytes = snprintf(buffer, 256, "%s", msg);
write(connection_fd, buffer, nbytes);
//}
close(connection_fd);
## -54,8 +54,6 ##
int socket_fd, connection_fd,res;
socklen_t address_length;
pid_t child;
-uid_t eid;
-gid_t gid;
socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
if(socket_fd < 0)
When coding http requests, i used Visual Studio for c++, now my code goes like this,
#define WIN32_LEAN_AND_MEAN
#include "stdafx.h"
#include <cstdio>
#include <cstdlib>
#include <Winsock2.h>
#include <WS2tcpip.h>
#include <windows.h>
#pragma comment (lib,"ws2_32")
int _tmain(int argc, _TCHAR* argv[])
{
WSADATA wsaData;
int iResult = WSAStartup(MAKEWORD(2,2),&wsaData);
SOCKET m_socket;
m_socket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(m_socket==INVALID_SOCKET)
{
printf("Invalid Socket :WSAGetLastError()");
}
sockaddr_in clientService;
clientService.sin_family = AF_INET;
clientService.sin_addr.s_addr = inet_addr("127.0.0.1");
clientService.sin_port = htons(5357);
LPHOSTENT host = gethostbyname("72.144.89.32");
if(connect(m_socket,(SOCKADDR*)&clientService,sizeof(clientService))==SOCKET_ERROR)
{
printf("Connection Failure");
WSACleanup();
return 1;
}
char buffer[2048];
strcpy(buffer,"POST /dbarea.php HTTP/1.1\n");
strcat(buffer,"Content - Type:application/x-www-form-urlencoded\n");
strcat(buffer,"Host: localost\n");
strcat(buffer,"content-Length:32\n");
strcat(buffer,"\n");
strcat(buffer,"username=emeka1&password=laikan112");
//int n = write(SOCKADDR*,buffer,strlen(buffer));
printf("Data Sent Successfully..");
return 0;
}
Now my php is like this
<?php
session_start();
$username = urldecode($_POST['username']);
$password = urldecode($_POST['password']);
echo "Username: $username\nPassword:$password";
?>
Now i have an issue on the php area , its not receiving information and printing it again for us to see, what could possibly be the problem?
There are several errors in your HTTP request.
You need to use \r\n instead of \n.
Content - Type needs to be Content-Type.
localost needs to be localhost.
content-Length:32 needs to be Content-Length: 34
Try this:
int _tmain(int argc, _TCHAR* argv[])
{
WSADATA wsaData;
int iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0)
{
printf("WinSock startup error: %d\n", iResult);
return 1;
}
SOCKET m_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (m_socket == INVALID_SOCKET)
{
printf("Socket creation error: %d\n", WSAGetLastError());
WSACleanup();
return 1;
}
sockaddr_in clientService = {0};
clientService.sin_family = AF_INET;
clientService.sin_addr.s_addr = inet_addr("127.0.0.1");
clientService.sin_port = htons(5357);
if (connect(m_socket, (SOCKADDR*)&clientService, sizeof(clientService)) == SOCKET_ERROR)
{
printf("Connection error: %d\n", WSAGetLastError());
closesocket(m_socket);
WSACleanup();
return 1;
}
char buffer[2048];
strcpy(buffer, "POST /dbarea.php HTTP/1.1\r\n");
strcat(buffer, "Content-Type: application/x-www-form-urlencoded\r\n");
strcat(buffer, "Host: localhost:5357\r\n");
strcat(buffer, "Content-Length: 34\r\n");
strcat(buffer, "\r\n");
strcat(buffer, "username=emeka1&password=laikan112");
char ptr = buffer;
int len = strlen(buffer);
do
{
int n = send(m_socket, ptr, len, 0);
if (n < 1)
{
if (n == SOCKET_ERROR)
printf("Send error: %d\n", WSAGetLastError());
else
printf("disconnected by server\n");
closesocket(m_socket);
WSACleanup();
return 1;
}
ptr += n;
len -= n;
}
while (len > 0);
printf("Data Sent Successfully..\n");
closesocket(m_socket);
WSACleanup();
return 0;
}
You really should not write your own HTTP code from scratch like this, when there are better alternatives available, such as Microsoft's WinInet/WinHTTP APIs, the curl library, etc. Let them do the hard work for you.
#include <WinInet.h>
#include <tchar.h>
void ReportWinInetError(const char *operation)
{
DWORD dwErr = GetLastError();
if (dwErr == ERROR_INTERNET_EXTENDED_ERROR)
{
LPTSTR szBuffer = NULL;
DWORD dwLength = 0;
BOOL bRet = InternetGetLastResponseInfo(&dwErr, NULL, &dwLength);
if ((bRet == FALSE) && (GetLastError() == ERROR_INSUFFICIENT_BUFFER))
{
szBuffer = new TCHAR[dwLength+1];
bRet = InternetGetLastResponseInfo(&dwErr, szBuffer, &dwLength);
}
if (bRet)
_tprintf(_T("WinInet error while %hs: %u %*s"), operation, dwErr, dwLength, szBuffer);
else
printf("Unknown WinInet error while %s", operation);
delete[] szBuffer;
}
else
printf("WinInet error while %s: %u", operation, dwErr);
}
int _tmain(int argc, _TCHAR* argv[])
{
HINTERNET hInternet = InternetOpen(TEXT("MyApp"), INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
if (!hInternet)
{
ReportWinInetError("opening session");
return 1;
}
HINTERNET hConnect = InternetConnect(hInternet, TEXT("127.0.0.1"), 5357, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0);
if (!hConnect)
{
ReportWinInetError("connecting session");
InternetCloseHandle(hInternet);
return 1;
}
HINTERNET hRequest = HttpOpenRequest(hConnect, TEXT("POST"), TEXT("/dbarea.php"), TEXT("HTTP/1.1"), NULL, NULL, 0, 0);
if (!hRequest)
{
ReportWinInetError("opening request");
InternetCloseHandle(hConnect);
InternetCloseHandle(hInternet);
return 1;
}
if (!HttpSendRequest(hRequest, TEXT("Content-Type: application/x-www-form-urlencoded"), -1, "username=emeka1&password=laikan112", 34))
{
ReportWinInetError("sending request");
InternetCloseHandle(hRequest);
InternetCloseHandle(hConnect);
InternetCloseHandle(hInternet);
return 1;
}
printf("Data Sent Successfully..\n");
InternetCloseHandle(hRequest);
InternetCloseHandle(hConnect);
InternetCloseHandle(hInternet);
return 0;
}
#include <curl/curl.h>
int _tmain(int argc, _TCHAR* argv[])
{
CURLCode ret = curl_global_init(CURL_GLOBAL_DEFAULT);
if (ret != CURLE_OK)
{
printf("Curl init error: %d\n", ret);
return 1;
}
CURL *curl = curl_easy_init();
if (!curl)
{
printf("Curl request creation error\n");
curl_global_cleanup();
return 1;
}
curl_easy_setopt(curl, CURLOPT_URL, "http://127.0.0.1:5357/dbarea.php");
curl_easy_setopt(curl, CURLOPT_POST, 1);
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "username=emeka1&password=laikan112");
curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, -1);
ret = curl_easy_perform(curl);
if (ret != CURLE_OK)
{
printf("Curl send error: %d\n", ret);
curl_easy_cleanup(curl);
curl_global_cleanup();
return 1;
}
printf("Data Sent Successfully..\n");
curl_easy_cleanup(curl);
curl_global_cleanup();
}
I am currently making a client and server program in the Unix Environment. I have made it so the client is able to upload the contents of a file to the client. I am now in the process of adding options and error handlers to the server example the client must enter the file name. To do this i wanted to send a message saying OK if all the options checked out however if i do this it seems to cause my file reading and sending to go Crazy and I have no idea why.
I have uploaded the functions for doing this
Client Code
int putFile (char path[256], int fd)
{
char mystring[1000];
char buffer[100];
int i , n;
FILE * pFile;
n = read(fd,buffer,100);
printf("%s", buffer);
if (strcmp(buffer, "OK") == 0)
{
pFile = fopen(path, "r");
if(pFile != NULL)
{
while(fgets(mystring, sizeof(mystring), pFile) != NULL)
{
//fputs(mystring, fd);
write(fd,mystring,strlen(mystring));
}
}
else
{
printf("Invalid File or Address \n");
}
fclose(pFile);
}
else
{
printf("%s \n", buffer);
}
}
Server Code for reading the socket
int putRequest(int fd, char buf[], char str[])
{
char data[256];
int number;
char * ptr;
char results[100];
int total = 0;
char *arguments[1024];
char temp[10];
int i;
ptr = strtok(buf," ");
while (ptr != NULL)
{
char * temp;
temp = (char *)malloc(sizeof(ptr));
temp = ptr;
arguments[total] = temp;
total++;
ptr = strtok (NULL, " ");
}
if(total == 1)
{
strcat(str, "Invaild Arguments \n");
return 1;
}
write(fd, "OK", 256);
FILE * pFile;
pFile = fopen ("myfile.txt","w");
if (pFile!=NULL)
{
while(read(fd, data, 256) != NULL)
{
fputs(data, pFile);
}
fclose (pFile);
}
else
{
strcat(str, "Invaild File");
return 0;
}
strcat(str, "Done");
return 1;
}
Thanks in advance and just post something if you need to see more code. I just placed the code which should be causing the problem.