diag_ftp_cmd(9)

💅 diag_ftp_cmd — like, the Kernel API Manual page for it, bestie

Okay so welcome to diag_ftp_cmd(9), the little kernel API page that tells you how to fire off a DIAG X'2C4' FTP command that's aimed at a HMC. Yes, that's a lot of acronyms in one breath. No, we're not scared of them. 💪

✨ NAME ✨

diag_ftp_cmd — executes a DIAG X'2C4' FTP command, targeting a HMC

🦋 SYNOPSIS 🦋

ssize_t diag_ftp_cmd (const struct hmcdrv_ftp_cmdspec *ftp , size_t *fsize );

🎀 ARGUMENTS 🎀

• ftp — pointer to the FTP command specification. Like, the whole vibe of what you wanna do lives in here.
• fsize — where the file size comes back to you (or NULL if that's simply not the energy you're on today 🙈).

🔥 DESCRIPTION 🔥

⚠️ Attention, bestie, this is the important part: this function is not reentrant — so the caller must ensure locking. Not optional. Not "eh, probably fine". The caller. Must. Ensure. Locking. periodt. 🔒

💀 RETURN 💀

It hands you back the number of bytes read/written… or a (negative) error code. So like, good news or bad news, but never no news. 😭

🌈 SEE ALSO 🌈

• Kernel file ./drivers/s390/char/diag_ftp.c
• struct diag_ftp_ldfpl(9)
• diag_ftp_handler(9)
• diag_ftp_2c4(9)
• diag_ftp_startup(9)
• diag_ftp_shutdown(9)

And that's the whole page, iykyk. This little icon lives over in ./drivers/s390/char, and the whole thing is dated October 2026 — so like, future-vibes fr fr. Go forth and lock your stuff. 🫶💖