Custom error message when incorrect-architecture OCI.DLL is in PATH on Windows

[kubo]

When incorrect-architecture OCI.DLL is in the PATH and correct-architecture OCI.DLL isn't there, GetLastError() returns ERROR_BAD_EXE_FORMAT(%1 is not a valid Win32 application). How about custom error message saying "c:\full\path\of\OCI.DLL is 32-bit, which isn't available in x64 programs" or so in this case?
This will reduce issues such as oracle/node-oracledb#752.

1. Search OCI.DLL as the step 1 in Custom error message when Visual Studio distributable package is not installed on Windows #48 (comment).
2. If all OCI.DLLs are incorrect-architecture, create a custom error message. Otherwise use message from FormatMessage().

Architecture could be checked by nt_hdr->FileHeader.Machine in #48 (comment) or by the following function.

#include <windows.h>

static void print_arch(const char *name)
{
    FILE *fp = fopen(name, "rb");
    IMAGE_DOS_HEADER dos_hdr;
    IMAGE_NT_HEADERS nt_hdr;

    if (fp == NULL) {
        printf("failed to open: %s\n", name);
        return;
    }
    fread(&dos_hdr, sizeof(dos_hdr), 1, fp);
    if (dos_hdr.e_magic != IMAGE_DOS_SIGNATURE) {
        printf("invalid DOS signature: 0x%x\n", dos_hdr.e_magic);
        fclose(fp);
        return;
    }
    fseek(fp, dos_hdr.e_lfanew, SEEK_SET);
    fread(&nt_hdr, sizeof(nt_hdr), 1, fp);
    fclose(fp);
    if (nt_hdr.Signature != IMAGE_NT_SIGNATURE) {
        printf("invalid NT signature: 0x%x\n", nt_hdr.Signature);
        return;
    }
    switch (nt_hdr.FileHeader.Machine) {
    case IMAGE_FILE_MACHINE_I386:
        printf("architecture is x86.\n");
        break;
    case IMAGE_FILE_MACHINE_AMD64:
        printf("architecture is x64.\n");
        break;
    case IMAGE_FILE_MACHINE_IA64:
        printf("architecture is IA64.\n");
        break;
    default:
        printf("invalid architecture: 0x%x\n", nt_hdr.FileHeader.Machine);
        break;
    }
}

[anthony-tuininga]

I just pushed a commit to address this. Please take a look and let me know if that addresses your request. Thanks!

[kubo]

Thank you! It works fine. But could you fix following?
Check the length of destination of strcpy and strcat to prevent buffer overrun.
When length > _MAX_DIR, it loops infinitely.
Use snprintf instead of sprintf to prevent buffer overrun.

As for this code I prefer predefined macros as follows to checking sizeof(void*).
But it is just my preference. There is no need to fix it.

#if defined _M_AMD64
    if (ntHeaders.FileHeader.Machine == IMAGE_FILE_MACHINE_AMD64)
        return 1;
#elif defined _M_IX86
    if (ntHeaders.FileHeader.Machine == IMAGE_FILE_MACHINE_I386)
        return 1;
#else
#error unsupported architecture
#endif

[anthony-tuininga]

I just pushed changes based on your suggestions. Thanks. Some of those should be "impossible", but the Windows documentation doesn't state it is, so better safe than sorry!

[kubo]

Thank you! It satisfies my request.