fix: Bounds-check read_from_file restores with snprintf

[VedantMadane]

Summary

Bounds-check read_from_file restores with snprintf

Changes

• file_system.cpp: replace strcpy with bounds-checked snprintf (4)

Fixes #34

[RomanAlexandroff]

Hi and welcome!

In secret_verification() and data_integrity_check(), snprintf and sizeof will work just fine.

However, in read_from_file(), sizeof will not work as you expect because here 'output' is a pointer to the char array, not the array itself. Calling sizeof(output) will return the size of the pointer which on a 32-bit system is just 4 bytes, causing snprintf to always copy at most 3 characters + a nul-terminator.

Instead, you've got to calculate the size to copy first and then pass it into read_from_file() e.g. like this:
read_from_file(const char* file_name, char* output, size_t output_size)

[VedantMadane]

Thank you for the review and explanation! I have updated
ead_from_file() to accept size_t output_size, updated the header declaration, and passed the explicit destination buffer sizes (sizeof(rtc_g.Secret) and sizeof(rtc_g.chat_id)) from
estore_data_value().

[VedantMadane]

Ready for re-review.

Maintainer feedback addressed

• read_from_file(const char* file_name, char* output, size_t output_size) now takes an explicit destination size (no sizeof on the pointer).
• Header declaration updated to match.
• Call sites pass real buffer sizes: sizeof(rtc_g.Secret) / sizeof(rtc_g.chat_id) via restore_data_value(..., destination_size).
• snprintf(output, output_size, %s, ...) uses that size; empty output_size rejected at entry.

Cleanup

• Removed leftover _pr_meta.json from the branch.
• Squashed onto current main as a single DCO-signed commit (55b4d15).

Please take another look when convenient. Thank you!

[VedantMadane]

Hi @RomanAlexandroff — gentle re-review bump.

read_from_file takes explicit output_size; leftover meta file removed. Ready when you are. Thanks!

[VedantMadane]

Hi @RomanAlexandroff — gentle re-review bump when you have a moment. Thanks!

[VedantMadane]

Verified: read_from_file(const char* file_name, char* output, size_t output_size) takes output_size and uses snprintf(output, output_size, "%s", buffer.c_str()) — no sizeof on the pointer. Call sites pass the destination buffer size.