tomoyo_write_self(9)

💖 NAME 💖

Okay bestie, this is tomoyo_write_self(9) from the Kernel API Manual, and it's literally the write() side of the /sys/kernel/security/tomoyo/self_domain interface. Main character syscall-adjacent energy, no cap. 💅

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✨ SYNOPSIS ✨

ssize_t tomoyo_write_self (struct file *file , const char __user *buf ,
       size_t count , loff_t *ppos );

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🎀 ARGUMENTS 🎀

• file — pointer to struct file. It's giving "the file object, bestie." 🦋
• buf — the domainname to transit to.
• count — size of buf.
• ppos — unused. Lowkey just vibing there. 🙈

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🌸 DESCRIPTION 🌸

It returns count on success, and a negative value otherwise. That's the whole return vibe. ✨

If domain transition was permitted but the domain transition failed, this function returns an error rather than terminating the current thread with SIGKILL.

💀 Okay so this part matters: permitted transition + failed transition = returns error, not SIGKILL for the current thread. Not me being dramatic, that's literally the behavior. Periodt.

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🔥 SEE ALSO 🔥

Bestie, the kernel file is ./security/tomoyo/securityfs_if.c, and the related squad is:

• tomoyo_check_task_acl(9)
• tomoyo_read_self(9)
• tomoyo_open(9)
• tomoyo_release(9)
• tomoyo_poll(9)
• tomoyo_read(9)
• tomoyo_write(9)
• tomoyo_create_entry(9)
• tomoyo_interface_init(9)

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💖 Cute sign-off time: this page comes from ./security/tomoyo, dated October 2026, and it's literally tomoyo_write_self(9). Slay. 🎀