ethtool_cpy(9)

💅 ethtool_cpy(9) — the Kernel API Manual, bestie edition 🎀

okay so this is ethtool_cpy(9) from the Kernel API Manual, and before you ask — yes, it's a whole little function for putting strings into ethtool string data, and yes, the "possibly-not-NUL-terminated" of it all is the main character here. Let's get into it ✨

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🌸 NAME 🌸

ethtool_cpy — write a string that might not be NUL-terminated into ethtool string data 🫶

like, that's literally the whole job. no cap.

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✨ SYNOPSIS ✨

ethtool_cpy (data , str );

that's it, that's the vibe check 💅

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🦋 ARGUMENTS 🦋

• data — a pointer to a pointer to the start of the string you're writing into. yes, double pointer. two layers. it's giving inception, but make it C 😭
• str — a NUL-byte padded char array of size ETH_GSTRING_LEN that you're copying from. note the padding, bestie — it's NUL-byte padded, not necessarily NUL-terminated, and that distinction is the whole plot 👑

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👑 SEE ALSO 👑

like a true icon, ethtool_cpy rolls deep. the whole clique lives in the kernel file ./include/linux/ethtool.h — here's everybody in the group chat 💖

• enum ethtool_phys_id_state(9)
• struct kernel_ethtool_ringparam(9)
• enum ethtool_supported_ring_param(9)
• ethtool_rxfh_indir_default(9)
• struct ethtool_rxfh_context(9)
• ethtool_link_ksettings_zero_link_mode(9)
• ethtool_link_ksettings_add_link_mode(9)
• ethtool_link_ksettings_del_link_mode(9)
• ethtool_link_ksettings_test_link_mode(9)
• ethtool_intersect_link_masks(9)
• struct ethtool_phy_stats(9)
• struct ethtool_pause_stats(9)
• struct ethtool_fec_hist_range(9)
• struct ethtool_fec_stats(9)
• struct ethtool_rmon_hist_range(9)
• struct ethtool_rmon_stats(9)
• struct ethtool_ts_stats(9)
• struct ethtool_module_eeprom(9)
• struct ethtool_module_power_mode_params(9)
• struct ethtool_mm_state(9)
• struct ethtool_mm_cfg(9)
• struct ethtool_mm_stats(9)
• struct ethtool_mmsv_ops(9)
• struct ethtool_mmsv(9)
• struct ethtool_rxfh_param(9)
• struct ethtool_rxfh_fields(9)
• struct kernel_ethtool_ts_info(9)
• struct ethtool_ops(9)
• struct ethtool_netdev_state(9)
• struct ethtool_phy_ops(9)
• ethtool_set_ethtool_phy_ops(9)
• ethtool_params_from_link_mode(9)
• ethtool_get_phc_vclocks(9)
• ethtool_mm_frag_size_add_to_min(9)
• ethtool_mm_frag_size_min_to_add(9)
• ethtool_get_ts_info_by_layer(9)
• ethtool_sprintf(9)
• ethtool_puts(9)

like I said — entire friend group. and honestly ethtool_sprintf(9) and ethtool_puts(9) are right there at the end being the sibling energy of it all 🌈

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ok real talk though bestie: str is only padded to ETH_GSTRING_LEN, so don't be out here assuming it's NUL-terminated. that's the whole reason this function exists instead of you just vibing with strcpy. respect the padding 🍓

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and that's the page!! 🧚 it lives in ./include/linux, dated October 2026, in the Kernel API Manual — mwah, sending you a big kiss, go forth and copy your strings correctly 💜🌸✨