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// This file named `set.rs` because possibly here will be other functions, not only hn
use crate::log::log_warning;
use libc::{c_char, sethostname, size_t};
use std::{ffi::CString, fs, io};
pub fn set_hostname() -> Result<(), Box<dyn std::error::Error>> {
let content = fs::read_to_string("/etc/hostname")
.map(|s| s.trim().to_string())
.unwrap_or_else(|_| "localhost".to_string());
if let Err(e) = perform_set_hostname(&content) {
match perform_set_hostname("localhost") {
Ok(_) => Err(format!(
"Failed to set hostname: \"{}\": {}. Fell back to localhost successfully.",
content, e
)
.into()),
Err(fallback_error) => {
log_warning(&format!(
"Failed to set hostname to '{}': {}. Also failed to set localhost: {}.",
content, e, fallback_error
));
Err(format!(
"Failed to set hostname '{}' and failed to fall back to localhost: {}.",
content, e
)
.into())
}
}
} else {
Ok(())
}
}
fn perform_set_hostname(name: &str) -> io::Result<()> {
if name.len() > 64 {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
"Hostname too long",
));
}
let c_str = CString::new(name)
.map_err(|_| io::Error::new(io::ErrorKind::InvalidInput, "Hostname contains null byte"))?;
let res = unsafe { sethostname(c_str.as_ptr() as *const c_char, name.len() as size_t) };
if res != 0 {
return Err(io::Error::last_os_error());
}
Ok(())
}
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