1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
use crate::{Error, Result};
#[cfg(not(target_os = "android"))]
use crate::NixPath;
use crate::errno::Errno;
#[cfg(not(target_os = "android"))]
use crate::fcntl::OFlag;
use libc::{self, c_int, c_void, size_t, off_t};
#[cfg(not(target_os = "android"))]
use crate::sys::stat::Mode;
use std::os::unix::io::RawFd;

libc_bitflags!{
    /// Desired memory protection of a memory mapping.
    pub struct ProtFlags: c_int {
        /// Pages cannot be accessed.
        PROT_NONE;
        /// Pages can be read.
        PROT_READ;
        /// Pages can be written.
        PROT_WRITE;
        /// Pages can be executed
        PROT_EXEC;
        /// Apply protection up to the end of a mapping that grows upwards.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        PROT_GROWSDOWN;
        /// Apply protection down to the beginning of a mapping that grows downwards.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        PROT_GROWSUP;
    }
}

libc_bitflags!{
    /// Additional parameters for `mmap()`.
    pub struct MapFlags: c_int {
        /// Compatibility flag. Ignored.
        MAP_FILE;
        /// Share this mapping. Mutually exclusive with `MAP_PRIVATE`.
        MAP_SHARED;
        /// Create a private copy-on-write mapping. Mutually exclusive with `MAP_SHARED`.
        MAP_PRIVATE;
        /// Place the mapping at exactly the address specified in `addr`.
        MAP_FIXED;
        /// Synonym for `MAP_ANONYMOUS`.
        MAP_ANON;
        /// The mapping is not backed by any file.
        #[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))]
        MAP_ANONYMOUS;
        /// Put the mapping into the first 2GB of the process address space.
        #[cfg(any(all(any(target_os = "android", target_os = "linux"),
                      any(target_arch = "x86", target_arch = "x86_64")),
                  all(target_os = "linux", target_env = "musl", any(target_arch = "x86", target_arch = "x86_64")),
                  all(target_os = "freebsd", target_pointer_width = "64")))]
        MAP_32BIT;
        /// Used for stacks; indicates to the kernel that the mapping should extend downward in memory.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_GROWSDOWN;
        /// Compatibility flag. Ignored.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_DENYWRITE;
        /// Compatibility flag. Ignored.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_EXECUTABLE;
        /// Mark the mmaped region to be locked in the same way as `mlock(2)`.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_LOCKED;
        /// Do not reserve swap space for this mapping.
        ///
        /// This was removed in FreeBSD 11.
        #[cfg(not(target_os = "freebsd"))]
        MAP_NORESERVE;
        /// Populate page tables for a mapping.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_POPULATE;
        /// Only meaningful when used with `MAP_POPULATE`. Don't perform read-ahead.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_NONBLOCK;
        /// Allocate the mapping using "huge pages."
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MAP_HUGETLB;
        /// Make use of 64KB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_64KB;
        /// Make use of 512KB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_512KB;
        /// Make use of 1MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_1MB;
        /// Make use of 2MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_2MB;
        /// Make use of 8MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_8MB;
        /// Make use of 16MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_16MB;
        /// Make use of 32MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_32MB;
        /// Make use of 256MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_256MB;
        /// Make use of 512MB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_512MB;
        /// Make use of 1GB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_1GB;
        /// Make use of 2GB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_2GB;
        /// Make use of 16GB huge page (must be supported by the system)
        #[cfg(target_os = "linux")]
        MAP_HUGE_16GB;

        /// Lock the mapped region into memory as with `mlock(2)`.
        #[cfg(target_os = "netbsd")]
        MAP_WIRED;
        /// Causes dirtied data in the specified range to be flushed to disk only when necessary.
        #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))]
        MAP_NOSYNC;
        /// Rename private pages to a file.
        ///
        /// This was removed in FreeBSD 11.
        #[cfg(any(target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd"))]
        MAP_RENAME;
        /// Region may contain semaphores.
        #[cfg(any(target_os = "dragonfly", target_os = "freebsd", target_os = "netbsd", target_os = "openbsd"))]
        MAP_HASSEMAPHORE;
        /// Region grows down, like a stack.
        #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd", target_os = "linux"))]
        MAP_STACK;
        /// Pages in this mapping are not retained in the kernel's memory cache.
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MAP_NOCACHE;
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MAP_JIT;
    }
}

libc_enum!{
    /// Usage information for a range of memory to allow for performance optimizations by the kernel.
    ///
    /// Used by [`madvise`](./fn.madvise.html).
    #[repr(i32)]
    pub enum MmapAdvise {
        /// No further special treatment. This is the default.
        MADV_NORMAL,
        /// Expect random page references.
        MADV_RANDOM,
        /// Expect sequential page references.
        MADV_SEQUENTIAL,
        /// Expect access in the near future.
        MADV_WILLNEED,
        /// Do not expect access in the near future.
        MADV_DONTNEED,
        /// Free up a given range of pages and its associated backing store.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_REMOVE,
        /// Do not make pages in this range available to the child after a `fork(2)`.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_DONTFORK,
        /// Undo the effect of `MADV_DONTFORK`.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_DOFORK,
        /// Poison the given pages.
        ///
        /// Subsequent references to those pages are treated like hardware memory corruption.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_HWPOISON,
        /// Enable Kernel Samepage Merging (KSM) for the given pages.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_MERGEABLE,
        /// Undo the effect of `MADV_MERGEABLE`
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_UNMERGEABLE,
        /// Preserve the memory of each page but offline the original page.
        #[cfg(any(target_os = "android",
            all(target_os = "linux", any(
                target_arch = "aarch64",
                target_arch = "arm",
                target_arch = "ppc",
                target_arch = "s390x",
                target_arch = "x86",
                target_arch = "x86_64",
                target_arch = "sparc64"))))]
        MADV_SOFT_OFFLINE,
        /// Enable Transparent Huge Pages (THP) for pages in the given range.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_HUGEPAGE,
        /// Undo the effect of `MADV_HUGEPAGE`.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_NOHUGEPAGE,
        /// Exclude the given range from a core dump.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_DONTDUMP,
        /// Undo the effect of an earlier `MADV_DONTDUMP`.
        #[cfg(any(target_os = "android", target_os = "linux"))]
        MADV_DODUMP,
        /// Specify that the application no longer needs the pages in the given range.
        MADV_FREE,
        /// Request that the system not flush the current range to disk unless it needs to.
        #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))]
        MADV_NOSYNC,
        /// Undoes the effects of `MADV_NOSYNC` for any future pages dirtied within the given range.
        #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))]
        MADV_AUTOSYNC,
        /// Region is not included in a core file.
        #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))]
        MADV_NOCORE,
        /// Include region in a core file
        #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))]
        MADV_CORE,
        #[cfg(any(target_os = "freebsd"))]
        MADV_PROTECT,
        /// Invalidate the hardware page table for the given region.
        #[cfg(target_os = "dragonfly")]
        MADV_INVAL,
        /// Set the offset of the page directory page to `value` for the virtual page table.
        #[cfg(target_os = "dragonfly")]
        MADV_SETMAP,
        /// Indicates that the application will not need the data in the given range.
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MADV_ZERO_WIRED_PAGES,
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MADV_FREE_REUSABLE,
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MADV_FREE_REUSE,
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MADV_CAN_REUSE,
    }
}

libc_bitflags!{
    /// Configuration flags for `msync`.
    pub struct MsFlags: c_int {
        /// Schedule an update but return immediately.
        MS_ASYNC;
        /// Invalidate all cached data.
        MS_INVALIDATE;
        /// Invalidate pages, but leave them mapped.
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MS_KILLPAGES;
        /// Deactivate pages, but leave them mapped.
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        MS_DEACTIVATE;
        /// Perform an update and wait for it to complete.
        MS_SYNC;
    }
}

libc_bitflags!{
    /// Flags for `mlockall`.
    pub struct MlockAllFlags: c_int {
        /// Lock pages that are currently mapped into the address space of the process.
        MCL_CURRENT;
        /// Lock pages which will become mapped into the address space of the process in the future.
        MCL_FUTURE;
    }
}

/// Locks all memory pages that contain part of the address range with `length`
/// bytes starting at `addr`.
///
/// Locked pages never move to the swap area.
///
/// # Safety
///
/// `addr` must meet all the requirements described in the `mlock(2)` man page.
pub unsafe fn mlock(addr: *const c_void, length: size_t) -> Result<()> {
    Errno::result(libc::mlock(addr, length)).map(drop)
}

/// Unlocks all memory pages that contain part of the address range with
/// `length` bytes starting at `addr`.
///
/// # Safety
///
/// `addr` must meet all the requirements described in the `munlock(2)` man
/// page.
pub unsafe fn munlock(addr: *const c_void, length: size_t) -> Result<()> {
    Errno::result(libc::munlock(addr, length)).map(drop)
}

/// Locks all memory pages mapped into this process' address space.
///
/// Locked pages never move to the swap area.
///
/// # Safety
///
/// `addr` must meet all the requirements described in the `mlockall(2)` man
/// page.
pub fn mlockall(flags: MlockAllFlags) -> Result<()> {
    unsafe { Errno::result(libc::mlockall(flags.bits())) }.map(drop)
}

/// Unlocks all memory pages mapped into this process' address space.
pub fn munlockall() -> Result<()> {
    unsafe { Errno::result(libc::munlockall()) }.map(drop)
}

/// allocate memory, or map files or devices into memory
///
/// # Safety
///
/// See the `mmap(2)` man page for detailed requirements.
pub unsafe fn mmap(addr: *mut c_void, length: size_t, prot: ProtFlags, flags: MapFlags, fd: RawFd, offset: off_t) -> Result<*mut c_void> {
    let ret = libc::mmap(addr, length, prot.bits(), flags.bits(), fd, offset);

    if ret == libc::MAP_FAILED {
        Err(Error::Sys(Errno::last()))
    } else {
        Ok(ret)
    }
}

/// remove a mapping
///
/// # Safety
///
/// `addr` must meet all the requirements described in the `munmap(2)` man
/// page.
pub unsafe fn munmap(addr: *mut c_void, len: size_t) -> Result<()> {
    Errno::result(libc::munmap(addr, len)).map(drop)
}

/// give advice about use of memory
///
/// # Safety
///
/// See the `madvise(2)` man page.  Take special care when using
/// `MmapAdvise::MADV_FREE`.
pub unsafe fn madvise(addr: *mut c_void, length: size_t, advise: MmapAdvise) -> Result<()> {
    Errno::result(libc::madvise(addr, length, advise as i32)).map(drop)
}

/// Set protection of memory mapping.
///
/// See [`mprotect(3)`](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mprotect.html) for
/// details.
///
/// # Safety
///
/// Calls to `mprotect` are inherently unsafe, as changes to memory protections can lead to
/// SIGSEGVs.
///
/// ```
/// # use nix::libc::size_t;
/// # use nix::sys::mman::{mmap, mprotect, MapFlags, ProtFlags};
/// # use std::ptr;
/// const ONE_K: size_t = 1024;
/// let mut slice: &mut [u8] = unsafe {
///     let mem = mmap(ptr::null_mut(), ONE_K, ProtFlags::PROT_NONE,
///                    MapFlags::MAP_ANON | MapFlags::MAP_PRIVATE, -1, 0).unwrap();
///     mprotect(mem, ONE_K, ProtFlags::PROT_READ | ProtFlags::PROT_WRITE).unwrap();
///     std::slice::from_raw_parts_mut(mem as *mut u8, ONE_K)
/// };
/// assert_eq!(slice[0], 0x00);
/// slice[0] = 0xFF;
/// assert_eq!(slice[0], 0xFF);
/// ```
pub unsafe fn mprotect(addr: *mut c_void, length: size_t, prot: ProtFlags) -> Result<()> {
    Errno::result(libc::mprotect(addr, length, prot.bits())).map(drop)
}

/// synchronize a mapped region
///
/// # Safety
///
/// `addr` must meet all the requirements described in the `msync(2)` man
/// page.
pub unsafe fn msync(addr: *mut c_void, length: size_t, flags: MsFlags) -> Result<()> {
    Errno::result(libc::msync(addr, length, flags.bits())).map(drop)
}

#[cfg(not(target_os = "android"))]
pub fn shm_open<P: ?Sized + NixPath>(name: &P, flag: OFlag, mode: Mode) -> Result<RawFd> {
    let ret = name.with_nix_path(|cstr| {
        #[cfg(any(target_os = "macos", target_os = "ios"))]
        unsafe {
            libc::shm_open(cstr.as_ptr(), flag.bits(), mode.bits() as libc::c_uint)
        }
        #[cfg(not(any(target_os = "macos", target_os = "ios")))]
        unsafe {
            libc::shm_open(cstr.as_ptr(), flag.bits(), mode.bits() as libc::mode_t)
        }
    })?;

    Errno::result(ret)
}

#[cfg(not(target_os = "android"))]
pub fn shm_unlink<P: ?Sized + NixPath>(name: &P) -> Result<()> {
    let ret = name.with_nix_path(|cstr| {
        unsafe { libc::shm_unlink(cstr.as_ptr()) }
    })?;

    Errno::result(ret).map(drop)
}