In the extension for postgresql, I encrypt char*, get a BYTE buffer, write it to a file, and return it as bytea* via PG_RETURN_BYTEA_P. When I try to read the same through bytea* b = PG_GETARG_BYTEA_P, the read does not match what I wrote to the file. How to read bytea correctly to get BYTE and decrypt again? Everything is in C.
Part of code:
FILE* log = AllocateFile("C:\\pg\\log.txt", PG_BINARY_A);
//get data to decrypt
bytea* dataToDecrypt = PG_GETARG_BYTEA_P(0);
FILE* tempFile = AllocateFile("C:\\pg\\file1.txt", PG_BINARY_A);
fwrite(dataToDecrypt, sizeof(dataToDecrypt), 1, tempFile);
FreeFile(tempFile);
I put the data in a file1 to use an example from Microsoft. Further everything as in the example https://learn.microsoft.com/en-us/windows/win32/seccrypto/example-c-program-decrypting-a-file
In the end:
FreeFile(log);
PG_RETURN_BYTEA_P(pbBuffer);
Related
Hey guys i need to read something from file and put that in buffer, so i use fread function. My code is:
duzina = configs[i].lenght * 1048576;
printf("Duzina %d[B]: %d\n",i+1,duzina);
printf("Duzina %d[MB]: %d\n",i+1,duzina/1048576);
printf("Duzina %d[B]: %d\n",i+1,duzina);
ukupna_duzina = ukupna_duzina + duzina;
printf("Ukupna duzina[B]: %d\n",ukupna_duzina);
printf("Ukupna duzina[MB]: %d\n",ukupna_duzina/1048576);
procitano[i] = fread(buffers[i],1,duzina,fp);
printf("Procitano %d[B]\n",procitano[i]);
perror("PERROR KAZE: ");
fseek(fp,ukupna_duzina,SEEK_SET);
In terminal, i get right size for duzina, 2,097,152B, perror returns no_error, but procitano[i] which is size_t type gives me 2 064 384 B. Also when i open file i need to read from his size is good -> 2,097,152B. So what is happening?
We use testing equipment (1995 year manufacturing) powered by MS DOS. Analog-digital converter records information in the file.
In [picture1] is shown the structure of that file.
In [picture2] is shown the oscillogram that constructed according to the data from the file (program for opening the file on MS DOS).
Below I placed link to this file (google drive).
This file contains the data that need for me - the massive of point of oscillogram. I want have opportunities to keep, analyze and print this chart on Windows or Linux (not MS DOS). So I need to extract data from the file.
But I can't make it. And no program (known to me) can't open this file. I analyzed a few first byte and they point to program 'TRAS v4.99'. This program is on MS DOS.
But I really hope, that it is really to get data without this program.
P.S. If anyone will say it is impossible - it is will well too because I haven't found point of view yet:)
Thank you for your time! Best regards!
LINK TO FILE ON GOOGLE DISK - 00014380.K00
STRUCTURE OF FILE
OPENING FILE VIA PROGRAM IN MS DOS
Here is an idea on how you can tackle this problem. Since the format is relatively well specified in the handbook you can use the Java programming language for example with something like java.io.RandomAccessFile to read arrays of bytes. These arrays of bytes can then be converted to Java primitive types OR to string according to the data type. After this conversion you can the print out the data in a human readable format.
Below you can find some sample code to give you an idea of what you could do with this approach (I have not tested the code, it is not complete, it is just to give you an idea of what you can do):
public static void readBinaryfile() throws IOException {
java.io.RandomAccessFile randomAccessFile = new RandomAccessFile("test.bin", "r");
byte[] addKenStrBytes = new byte[12];
randomAccessFile.read(addKenStrBytes);
String addKenStr = new String(addKenStrBytes, "UTF-8");
// TODO: Do something with addKenStr.
System.out.println(addKenStr);
byte[] kopfSizeBytes = new byte[2];
randomAccessFile.read(kopfSizeBytes);
// TODO: Do something with kopfSizeBytes
System.out.println(convertToInt(kopfSizeBytes));
byte[] addRufNrCounterBytes = new byte[6];
randomAccessFile.read(addRufNrCounterBytes);
long addRufNrCounter = convertToLong(addRufNrCounterBytes);
// TODO: Do something with addRufNrCounter
System.out.println(addRufNrCounter);
byte[] endAdrBytes = new byte[4];
randomAccessFile.read(endAdrBytes);
// TODO: Do something with endAdrBytes
System.out.println(convertToLong(endAdrBytes));
// Continue here and after you reached the end of the record repeat until you reached the end off the file
}
private static int convertToInt(byte[] bytes) {
if(bytes.length > 4) {
throw new IllegalArgumentException();
}
int buffer = 0;
for(byte b : bytes) {
buffer |= b;
buffer = buffer << 8;
}
return buffer;
}
private static long convertToLong(byte[] bytes) {
if(bytes.length > 8) {
throw new IllegalArgumentException();
}
long buffer = 0L;
for(byte b : bytes) {
buffer |= b;
buffer = buffer << 8;
}
return buffer;
}
Note that fields with more than 8 bytes need to be most probably converted to strings. This is not complete code, just an example to give you an idea on how you can tackle this problem.
I'm trying to open this file (final.txt) and read the contents:
c0001
f260
L
D11
H30
R0000
C0040
1X1100000100010B300300003003
181100202900027Part No
181100202900097[PRTNUM]
1e5504002400030B
1X1100002300010L300003
191100202000030Quantity
191100202000080[QUANTY]
1e5504001500040B
1X1100001400010L300003
1X1100001400150L003090
191100202000170P.O.No
191100202000220[PONUMB]
1e5504001500180B
191100201200030Supplier
1e3304000700030B
1X1100000600010L300003
181100200300030Serial
181100200300090[SERIAL]
171100300900190Rev
171100300300190[REV]
171100300900240Units
171100300300240[UNITS]
1X1100000100180L003130
Q0001
E
from which I am reading only [PRTNUM], [QUANTY], [PONUMB], [SERIAL], [UNITS].
I've written the following C program:
char* cStart = strchr(cString, '[');
if (cStart)
{
// open bracket found
*cStart++ = '\0'; // split the string at [
char* cEnd = strchr(cStart, ']');
// you could check here for the close bracket being found
// and throw an exception if not
*cEnd = '\0'; // terminate the keyword
printf("Key: %s, Value: %s",cString, cStart);
}
// continue the loop
but now I want to replace these placeholders with data from the 2nd file:
132424235
004342
L1000
DZ12
234235
234235
I want to replace [PRTNUM] (from the 1st file) with 132424235 and so on... In the end my file should be updated with all this data. Can you tell me what function I should use in the above program?
If you don't mind having an alternate approach, here's an algorithm to do the work in an elegant way
Create one (large enough) temporary buffer. Also, create (open) one output file which will be the modified version.
Read a line from the input file into the buffer using fgets()
Search for the particular "keyword" using strstr()
If a match is found --
4.1. Open the other input file.
4.2. Read the corresponding data (line), using fgets()
4.3. Replace the actual data in the temporary buffer with the newly read value.
4.4. write the modified data to the output file.
If match is not found, write the original data in the output file. Then, go to step 2.
Continue until fgets() returns NULL (indicates the file content has been exhausted).
Finally, the output file will have the data from the first file with those particular "placeholders" substituted with the value read from the second file.
Obviously, you need to polish the algorithm a little bit to make it work with multiple "placeholder" string.
Keep an extra string(name it copy) large enough to hold file 1 + some extra to manage replacement of [PRTNUM] with 132424235.
Start reading first string that has file1 and keep copying into second string (copy) as soon as you encounter [PRTNUM] , in string 2 instead of copying [PRTNUM] you append it with 132424235 and so on for all others.
And finally replace file1.txt with this second (copy) string.
I have a struct which holds some ByteArray data
typedef struct {
uint32_t length;
uint8_t* bytes;
} FREByteArray;
And here I am trying to save this to a file
FREByteArray byteArray;
if((fileToWrite = fopen(filePath, "wb+")) != NULL){
fwrite(&byteArray.bytes, 1, byteArray.length, fileToWrite);
fclose(fileToWrite);
}
But this doesn't seem to be saving all of the data, the saved file size is 16KB, actual data is about 32KB. I think fwrite is not able to write the whole bytearray to the file.
Is this the correct way to save the ByteArray? Is there a limit how much fwrite can handle in a single call?
Replace
fwrite(&byteArray.bytes, 1, byteArray.length, fileToWrite);
with
fwrite(byteArray.bytes, 1, byteArray.length, fileToWrite);
And as pointed out by #Sourav Ghosh make sure that byteArray.bytes is pointing to the correct source location.
Hi fellow stack overflowers,
I'm currently parsing a file which both contains text and binary data. Currently, I'm reading the file in following manner:
QTextStream in(&file);
int index = 0;
while(!in.atEnd()) {
if (index==0) {
QString line = in.readLine(); // parse file here
} else {
QByteArray raw_data(in.readAll().toAscii());
data = new QByteArray(raw_data);
}
index++;
}
where data refers to the binary data I'm looking for. I'm not sure if this is what I want, since the QString is encoded into ascii and I have no idea if some bytes are lost.
I checked the documentation, and it recommends using a QDataStream. How can I combine both approaches, i.e. read lines with an encoding and also read the binary dump, after one line break?
Help is greatly appreciated!
This will do what you want.
QTextStream t(&in);
QString line;
QByteArray raw_data;
if(!in.atEnd()) {line = t.readLine();}
in.reset();
int lineSize = line.toLocal8Bit().size() + 1;
in.seek(lineSize);
if(!in.atEnd())
{
int len = in.size() - lineSize;
QDataStream d(&in);
char *raw = new char[len]();
d.readRawData(raw, len);
raw_data = QByteArray(raw, len);
delete raw;
}
PS: if file format is yours, it will be better to create file with QDataStream and write data with <<, read with >>. This way you can store QByteArray and QString in file without such problems.