From: Lukas Wagner <l.wagner@proxmox.com>
To: pve-devel@lists.proxmox.com, pbs-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH proxmox v2 3/5] time: posix: add bindings for strftime_l
Date: Mon, 11 Dec 2023 14:29:06 +0100 [thread overview]
Message-ID: <20231211132908.267921-4-l.wagner@proxmox.com> (raw)
In-Reply-To: <20231211132908.267921-1-l.wagner@proxmox.com>
This variant of strftime can be provided with a locale_t, which
determines the locale used for time formatting.
A struct `Locale` was also introduced as a safe wrapper around
locale_t.
Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>
---
proxmox-time/src/posix.rs | 99 +++++++++++++++++++++++++++++++++++++++
1 file changed, 99 insertions(+)
diff --git a/proxmox-time/src/posix.rs b/proxmox-time/src/posix.rs
index 5913816..9c8002a 100644
--- a/proxmox-time/src/posix.rs
+++ b/proxmox-time/src/posix.rs
@@ -140,6 +140,93 @@ pub fn strftime(format: &str, t: &libc::tm) -> Result<String, Error> {
Ok(str_slice.to_owned())
}
+// The `libc` crate does not yet contain bindings for `strftime_l`
+#[link(name = "c")]
+extern "C" {
+ #[link_name = "strftime_l"]
+ fn libc_strftime_l(
+ s: *mut libc::c_char,
+ max: libc::size_t,
+ format: *const libc::c_char,
+ time: *const libc::tm,
+ locale: libc::locale_t,
+ ) -> libc::size_t;
+}
+
+/// Safe bindings to libc's `strftime_l`
+///
+/// The compared to `strftime`, `strftime_l` allows the caller to provide a
+/// locale object.
+pub fn strftime_l(format: &str, t: &libc::tm, locale: &Locale) -> Result<String, Error> {
+ let format = CString::new(format).map_err(|err| format_err!("{err}"))?;
+ let mut buf = vec![0u8; 8192];
+
+ let res = unsafe {
+ libc_strftime_l(
+ buf.as_mut_ptr() as *mut libc::c_char,
+ buf.len() as libc::size_t,
+ format.as_ptr(),
+ t as *const libc::tm,
+ locale.locale,
+ )
+ };
+ if res == !0 {
+ // -1,, it's unsigned
+ // man strftime: POSIX.1-2001 does not specify any errno settings for strftime()
+ bail!("strftime failed");
+ }
+
+ // `res` is a `libc::size_t`, which on a different target architecture might not be directly
+ // assignable to a `usize`. Thus, we actually want a cast here.
+ #[allow(clippy::unnecessary_cast)]
+ let len = res as usize;
+
+ if len == 0 {
+ bail!("strftime: result len is 0 (string too large)");
+ };
+
+ let c_str = CStr::from_bytes_with_nul(&buf[..len + 1]).map_err(|err| format_err!("{err}"))?;
+ let str_slice: &str = c_str.to_str()?;
+ Ok(str_slice.to_owned())
+}
+
+/// A safe wrapper for `libc::locale_t`.
+///
+/// The enclosed locale object will be automatically freed by `Drop::drop`
+pub struct Locale {
+ locale: libc::locale_t,
+}
+
+impl Locale {
+ /// Portable, minimal locale environment
+ const C: &'static str = "C";
+
+ /// Create a new locale object.
+ /// `category_mask` is expected to be a bitmask based on the
+ /// LC_*_MASK constants from libc. The locale will be set to `locale`
+ /// for every entry in the bitmask which is set.
+ pub fn new(category_mask: i32, locale: &str) -> Result<Self, Error> {
+ let format = CString::new(locale).map_err(|err| format_err!("{err}"))?;
+
+ let locale =
+ unsafe { libc::newlocale(category_mask, format.as_ptr(), std::ptr::null_mut()) };
+
+ if locale.is_null() {
+ return Err(std::io::Error::last_os_error().into());
+ }
+
+ Ok(Self { locale })
+ }
+}
+
+impl Drop for Locale {
+ fn drop(&mut self) {
+ unsafe {
+ libc::freelocale(self.locale);
+ }
+ }
+}
+
/// Format epoch as local time
pub fn strftime_local(format: &str, epoch: i64) -> Result<String, Error> {
let localtime = localtime(epoch)?;
@@ -391,3 +478,15 @@ fn test_timezones() {
let res = epoch_to_rfc3339_utc(parsed).expect("converting to RFC failed");
assert_eq!(expected_utc, res);
}
+
+#[test]
+fn test_strftime_l() {
+ let epoch = 1609263000;
+
+ let locale = Locale::new(libc::LC_ALL, Locale::C).expect("could not create locale");
+ let time = gmtime(epoch).expect("gmtime failed");
+
+ let formatted = strftime_l("%a, %d %b %Y %T %z", &time, &locale).expect("strftime_l failed");
+
+ assert_eq!(formatted, "Tue, 29 Dec 2020 17:30:00 +0000");
+}
--
2.39.2
next prev parent reply other threads:[~2023-12-11 13:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-11 13:29 [pve-devel] [PATCH proxmox v2 0/5] sys: email: always format 'Date' header with C locale Lukas Wagner
2023-12-11 13:29 ` [pve-devel] [PATCH proxmox v2 1/5] time: posix: use strftime from the `libc` crate Lukas Wagner
2023-12-11 13:29 ` [pve-devel] [PATCH proxmox v2 2/5] time: posix: inline vars in string formatting Lukas Wagner
2023-12-11 13:29 ` Lukas Wagner [this message]
2023-12-11 13:29 ` [pve-devel] [PATCH proxmox v2 4/5] time: posix: add epoch_to_rfc2822 Lukas Wagner
2023-12-11 13:29 ` [pve-devel] [PATCH proxmox v2 5/5] sys: email: use `epoch_to_rfc2822` from proxmox_time Lukas Wagner
2024-01-08 10:42 ` [pve-devel] [PATCH proxmox v2 0/5] sys: email: always format 'Date' header with C locale Lukas Wagner
2024-01-08 11:13 ` [pve-devel] applied-series: " Wolfgang Bumiller
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