1//! Process execution domains
2use crate::errno::Errno;
3use crate::Result;
4
5use libc::{self, c_int, c_ulong};
6
7libc_bitflags! {
8    /// Flags used and returned by [`get()`](fn.get.html) and
9    /// [`set()`](fn.set.html).
10    pub struct Persona: c_int {
11        /// Provide the legacy virtual address space layout.
12        ADDR_COMPAT_LAYOUT;
13        /// Disable address-space-layout randomization.
14        ADDR_NO_RANDOMIZE;
15        /// Limit the address space to 32 bits.
16        ADDR_LIMIT_32BIT;
17        /// Use `0xc0000000` as the offset at which to search a virtual memory
18        /// chunk on [`mmap(2)`], otherwise use `0xffffe000`.
19        ///
20        /// [`mmap(2)`]: https://man7.org/linux/man-pages/man2/mmap.2.html
21        ADDR_LIMIT_3GB;
22        /// User-space function pointers to signal handlers point to descriptors.
23        #[cfg(not(any(target_env = "musl", target_env = "ohos", target_env = "uclibc")))]
24        #[cfg_attr(docsrs, doc(cfg(all())))]
25        FDPIC_FUNCPTRS;
26        /// Map page 0 as read-only.
27        MMAP_PAGE_ZERO;
28        /// `PROT_READ` implies `PROT_EXEC` for [`mmap(2)`].
29        ///
30        /// [`mmap(2)`]: https://man7.org/linux/man-pages/man2/mmap.2.html
31        READ_IMPLIES_EXEC;
32        /// No effects.
33        SHORT_INODE;
34        /// [`select(2)`], [`pselect(2)`], and [`ppoll(2)`] do not modify the
35        /// returned timeout argument when interrupted by a signal handler.
36        ///
37        /// [`select(2)`]: https://man7.org/linux/man-pages/man2/select.2.html
38        /// [`pselect(2)`]: https://man7.org/linux/man-pages/man2/pselect.2.html
39        /// [`ppoll(2)`]: https://man7.org/linux/man-pages/man2/ppoll.2.html
40        STICKY_TIMEOUTS;
41        /// Have [`uname(2)`] report a 2.6.40+ version number rather than a 3.x
42        /// version number.
43        ///
44        /// [`uname(2)`]: https://man7.org/linux/man-pages/man2/uname.2.html
45        #[cfg(not(any(target_env = "musl", target_env = "ohos", target_env = "uclibc")))]
46        #[cfg_attr(docsrs, doc(cfg(all())))]
47        UNAME26;
48        /// No effects.
49        WHOLE_SECONDS;
50    }
51}
52
53/// Retrieve the current process personality.
54///
55/// Returns a Result containing a Persona instance.
56///
57/// Example:
58///
59/// ```
60/// # use nix::sys::personality::{self, Persona};
61/// let pers = personality::get().unwrap();
62/// assert!(!pers.contains(Persona::WHOLE_SECONDS));
63/// ```
64pub fn get() -> Result<Persona> {
65    let res = unsafe { libc::personality(0xFFFFFFFF) };
66
67    Errno::result(res).map(Persona::from_bits_truncate)
68}
69
70/// Set the current process personality.
71///
72/// Returns a Result containing the *previous* personality for the
73/// process, as a Persona.
74///
75/// For more information, see [personality(2)](https://man7.org/linux/man-pages/man2/personality.2.html)
76///
77/// **NOTE**: This call **replaces** the current personality entirely.
78/// To **update** the personality, first call `get()` and then `set()`
79/// with the modified persona.
80///
81/// Example:
82///
83/// ```
84/// # use nix::sys::personality::{self, Persona};
85/// let mut pers = personality::get().unwrap();
86/// assert!(!pers.contains(Persona::ADDR_NO_RANDOMIZE));
87/// personality::set(pers | Persona::ADDR_NO_RANDOMIZE).unwrap();
88/// ```
89pub fn set(persona: Persona) -> Result<Persona> {
90    let res = unsafe { libc::personality(persona.bits() as c_ulong) };
91
92    Errno::result(res).map(Persona::from_bits_truncate)
93}
94