src/libstd/sys/windows/os.rs

   1 //! Implementation of `std::os` functionality for Windows.
   2
   3 #![allow(nonstandard_style)]
   4
   5 use crate::os::windows::prelude::*;
   6
   7 use crate::error::Error as StdError;
   8 use crate::ffi::{OsStr, OsString};
   9 use crate::fmt;
  10 use crate::io;
  11 use crate::os::windows::ffi::EncodeWide;
  12 use crate::path::{self, PathBuf};
  13 use crate::ptr;
  14 use crate::slice;
  15 use crate::sys::{c, cvt};
  16
  17 use super::to_u16s;
  18
  19 pub fn errno() -> i32 {
  20     unsafe { c::GetLastError() as i32 }
  21 }
  22
  23 /// Gets a detailed string description for the given error number.
  24 pub fn error_string(mut errnum: i32) -> String {
  25     // This value is calculated from the macro
  26     // MAKELANGID(LANG_SYSTEM_DEFAULT, SUBLANG_SYS_DEFAULT)
  27     let langId = 0x0800 as c::DWORD;
  28
  29     let mut buf = [0 as c::WCHAR; 2048];
  30
  31     unsafe {
  32         let mut module = ptr::null_mut();
  33         let mut flags = 0;
  34
  35         // NTSTATUS errors may be encoded as HRESULT, which may returned from
  36         // GetLastError. For more information about Windows error codes, see
  37         // `[MS-ERREF]`: https://msdn.microsoft.com/en-us/library/cc231198.aspx
  38         if (errnum & c::FACILITY_NT_BIT as i32) != 0 {
  39             // format according to https://support.microsoft.com/en-us/help/259693
  40             const NTDLL_DLL: &[u16] = &[
  41                 'N' as _, 'T' as _, 'D' as _, 'L' as _, 'L' as _, '.' as _, 'D' as _, 'L' as _,
  42                 'L' as _, 0,
  43             ];
  44             module = c::GetModuleHandleW(NTDLL_DLL.as_ptr());
  45
  46             if module != ptr::null_mut() {
  47                 errnum ^= c::FACILITY_NT_BIT as i32;
  48                 flags = c::FORMAT_MESSAGE_FROM_HMODULE;
  49             }
  50         }
  51
  52         let res = c::FormatMessageW(
  53             flags | c::FORMAT_MESSAGE_FROM_SYSTEM | c::FORMAT_MESSAGE_IGNORE_INSERTS,
  54             module,
  55             errnum as c::DWORD,
  56             langId,
  57             buf.as_mut_ptr(),
  58             buf.len() as c::DWORD,
  59             ptr::null(),
  60         ) as usize;
  61         if res == 0 {
  62             // Sometimes FormatMessageW can fail e.g., system doesn't like langId,
  63             let fm_err = errno();
  64             return format!("OS Error {} (FormatMessageW() returned error {})", errnum, fm_err);
  65         }
  66
  67         match String::from_utf16(&buf[..res]) {
  68             Ok(mut msg) => {
  69                 // Trim trailing CRLF inserted by FormatMessageW
  70                 let len = msg.trim_end().len();
  71                 msg.truncate(len);
  72                 msg
  73             }
  74             Err(..) => format!(
  75                 "OS Error {} (FormatMessageW() returned \
  76                  invalid UTF-16)",
  77                 errnum
  78             ),
  79         }
  80     }
  81 }
  82
  83 pub struct Env {
  84     base: c::LPWCH,
  85     cur: c::LPWCH,
  86 }
  87
  88 impl Iterator for Env {
  89     type Item = (OsString, OsString);
  90
  91     fn next(&mut self) -> Option<(OsString, OsString)> {
  92         loop {
  93             unsafe {
  94                 if *self.cur == 0 {
  95                     return None;
  96                 }
  97                 let p = &*self.cur as *const u16;
  98                 let mut len = 0;
  99                 while *p.offset(len) != 0 {
 100                     len += 1;
 101                 }
 102                 let s = slice::from_raw_parts(p, len as usize);
 103                 self.cur = self.cur.offset(len + 1);
 104
 105                 // Windows allows environment variables to start with an equals
 106                 // symbol (in any other position, this is the separator between
 107                 // variable name and value). Since`s` has at least length 1 at
 108                 // this point (because the empty string terminates the array of
 109                 // environment variables), we can safely slice.
 110                 let pos = match s[1..].iter().position(|&u| u == b'=' as u16).map(|p| p + 1) {
 111                     Some(p) => p,
 112                     None => continue,
 113                 };
 114                 return Some((
 115                     OsStringExt::from_wide(&s[..pos]),
 116                     OsStringExt::from_wide(&s[pos + 1..]),
 117                 ));
 118             }
 119         }
 120     }
 121 }
 122
 123 impl Drop for Env {
 124     fn drop(&mut self) {
 125         unsafe {
 126             c::FreeEnvironmentStringsW(self.base);
 127         }
 128     }
 129 }
 130
 131 pub fn env() -> Env {
 132     unsafe {
 133         let ch = c::GetEnvironmentStringsW();
 134         if ch as usize == 0 {
 135             panic!("failure getting env string from OS: {}", io::Error::last_os_error());
 136         }
 137         Env { base: ch, cur: ch }
 138     }
 139 }
 140
 141 pub struct SplitPaths<'a> {
 142     data: EncodeWide<'a>,
 143     must_yield: bool,
 144 }
 145
 146 pub fn split_paths(unparsed: &OsStr) -> SplitPaths<'_> {
 147     SplitPaths { data: unparsed.encode_wide(), must_yield: true }
 148 }
 149
 150 impl<'a> Iterator for SplitPaths<'a> {
 151     type Item = PathBuf;
 152     fn next(&mut self) -> Option<PathBuf> {
 153         // On Windows, the PATH environment variable is semicolon separated.
 154         // Double quotes are used as a way of introducing literal semicolons
 155         // (since c:\some;dir is a valid Windows path). Double quotes are not
 156         // themselves permitted in path names, so there is no way to escape a
 157         // double quote.  Quoted regions can appear in arbitrary locations, so
 158         //
 159         //   c:\foo;c:\som"e;di"r;c:\bar
 160         //
 161         // Should parse as [c:\foo, c:\some;dir, c:\bar].
 162         //
 163         // (The above is based on testing; there is no clear reference available
 164         // for the grammar.)
 165
 166         let must_yield = self.must_yield;
 167         self.must_yield = false;
 168
 169         let mut in_progress = Vec::new();
 170         let mut in_quote = false;
 171         for b in self.data.by_ref() {
 172             if b == '"' as u16 {
 173                 in_quote = !in_quote;
 174             } else if b == ';' as u16 && !in_quote {
 175                 self.must_yield = true;
 176                 break;
 177             } else {
 178                 in_progress.push(b)
 179             }
 180         }
 181
 182         if !must_yield && in_progress.is_empty() {
 183             None
 184         } else {
 185             Some(super::os2path(&in_progress))
 186         }
 187     }
 188 }
 189
 190 #[derive(Debug)]
 191 pub struct JoinPathsError;
 192
 193 pub fn join_paths<I, T>(paths: I) -> Result<OsString, JoinPathsError>
 194 where
 195     I: Iterator<Item = T>,
 196     T: AsRef<OsStr>,
 197 {
 198     let mut joined = Vec::new();
 199     let sep = b';' as u16;
 200
 201     for (i, path) in paths.enumerate() {
 202         let path = path.as_ref();
 203         if i > 0 {
 204             joined.push(sep)
 205         }
 206         let v = path.encode_wide().collect::<Vec<u16>>();
 207         if v.contains(&(b'"' as u16)) {
 208             return Err(JoinPathsError);
 209         } else if v.contains(&sep) {
 210             joined.push(b'"' as u16);
 211             joined.extend_from_slice(&v[..]);
 212             joined.push(b'"' as u16);
 213         } else {
 214             joined.extend_from_slice(&v[..]);
 215         }
 216     }
 217
 218     Ok(OsStringExt::from_wide(&joined[..]))
 219 }
 220
 221 impl fmt::Display for JoinPathsError {
 222     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 223         "path segment contains `\"`".fmt(f)
 224     }
 225 }
 226
 227 impl StdError for JoinPathsError {
 228     fn description(&self) -> &str {
 229         "failed to join paths"
 230     }
 231 }
 232
 233 pub fn current_exe() -> io::Result<PathBuf> {
 234     super::fill_utf16_buf(
 235         |buf, sz| unsafe { c::GetModuleFileNameW(ptr::null_mut(), buf, sz) },
 236         super::os2path,
 237     )
 238 }
 239
 240 pub fn getcwd() -> io::Result<PathBuf> {
 241     super::fill_utf16_buf(|buf, sz| unsafe { c::GetCurrentDirectoryW(sz, buf) }, super::os2path)
 242 }
 243
 244 pub fn chdir(p: &path::Path) -> io::Result<()> {
 245     let p: &OsStr = p.as_ref();
 246     let mut p = p.encode_wide().collect::<Vec<_>>();
 247     p.push(0);
 248
 249     cvt(unsafe { c::SetCurrentDirectoryW(p.as_ptr()) }).map(|_| ())
 250 }
 251
 252 pub fn getenv(k: &OsStr) -> io::Result<Option<OsString>> {
 253     let k = to_u16s(k)?;
 254     let res = super::fill_utf16_buf(
 255         |buf, sz| unsafe { c::GetEnvironmentVariableW(k.as_ptr(), buf, sz) },
 256         |buf| OsStringExt::from_wide(buf),
 257     );
 258     match res {
 259         Ok(value) => Ok(Some(value)),
 260         Err(e) => {
 261             if e.raw_os_error() == Some(c::ERROR_ENVVAR_NOT_FOUND as i32) {
 262                 Ok(None)
 263             } else {
 264                 Err(e)
 265             }
 266         }
 267     }
 268 }
 269
 270 pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
 271     let k = to_u16s(k)?;
 272     let v = to_u16s(v)?;
 273
 274     cvt(unsafe { c::SetEnvironmentVariableW(k.as_ptr(), v.as_ptr()) }).map(|_| ())
 275 }
 276
 277 pub fn unsetenv(n: &OsStr) -> io::Result<()> {
 278     let v = to_u16s(n)?;
 279     cvt(unsafe { c::SetEnvironmentVariableW(v.as_ptr(), ptr::null()) }).map(|_| ())
 280 }
 281
 282 pub fn temp_dir() -> PathBuf {
 283     super::fill_utf16_buf(|buf, sz| unsafe { c::GetTempPathW(sz, buf) }, super::os2path).unwrap()
 284 }
 285
 286 #[cfg(not(target_vendor = "uwp"))]
 287 fn home_dir_crt() -> Option<PathBuf> {
 288     unsafe {
 289         use crate::sys::handle::Handle;
 290
 291         let me = c::GetCurrentProcess();
 292         let mut token = ptr::null_mut();
 293         if c::OpenProcessToken(me, c::TOKEN_READ, &mut token) == 0 {
 294             return None;
 295         }
 296         let _handle = Handle::new(token);
 297         super::fill_utf16_buf(
 298             |buf, mut sz| {
 299                 match c::GetUserProfileDirectoryW(token, buf, &mut sz) {
 300                     0 if c::GetLastError() != c::ERROR_INSUFFICIENT_BUFFER => 0,
 301                     0 => sz,
 302                     _ => sz - 1, // sz includes the null terminator
 303                 }
 304             },
 305             super::os2path,
 306         )
 307         .ok()
 308     }
 309 }
 310
 311 #[cfg(target_vendor = "uwp")]
 312 fn home_dir_crt() -> Option<PathBuf> {
 313     None
 314 }
 315
 316 pub fn home_dir() -> Option<PathBuf> {
 317     crate::env::var_os("HOME")
 318         .or_else(|| crate::env::var_os("USERPROFILE"))
 319         .map(PathBuf::from)
 320         .or_else(|| home_dir_crt())
 321 }
 322
 323 pub fn exit(code: i32) -> ! {
 324     unsafe { c::ExitProcess(code as c::UINT) }
 325 }
 326
 327 pub fn getpid() -> u32 {
 328     unsafe { c::GetCurrentProcessId() as u32 }
 329 }
 330
 331 #[cfg(test)]
 332 mod tests {
 333     use crate::io::Error;
 334     use crate::sys::c;
 335
 336     // tests `error_string` above
 337     #[test]
 338     fn ntstatus_error() {
 339         const STATUS_UNSUCCESSFUL: u32 = 0xc000_0001;
 340         assert!(
 341             !Error::from_raw_os_error((STATUS_UNSUCCESSFUL | c::FACILITY_NT_BIT) as _)
 342                 .to_string()
 343                 .contains("FormatMessageW() returned error")
 344         );
 345     }
 346 }