1 files changed, 424 insertions, 0 deletions
diff --git a/vendor/object/src/read/elf/version.rs b/vendor/object/src/read/elf/version.rs
new file mode 100644
index 0000000..28eeed0
--- /dev/null
+++ b/vendor/object/src/read/elf/version.rs
@@ -0,0 +1,424 @@
+use alloc::vec::Vec;
+
+use crate::read::{Bytes, ReadError, ReadRef, Result, StringTable};
+use crate::{elf, endian};
+
+use super::FileHeader;
+
+/// A version index.
+#[derive(Debug, Default, Clone, Copy)]
+pub struct VersionIndex(pub u16);
+
+impl VersionIndex {
+    /// Return the version index.
+    pub fn index(&self) -> u16 {
+        self.0 & elf::VERSYM_VERSION
+    }
+
+    /// Return true if it is the local index.
+    pub fn is_local(&self) -> bool {
+        self.index() == elf::VER_NDX_LOCAL
+    }
+
+    /// Return true if it is the global index.
+    pub fn is_global(&self) -> bool {
+        self.index() == elf::VER_NDX_GLOBAL
+    }
+
+    /// Return the hidden flag.
+    pub fn is_hidden(&self) -> bool {
+        self.0 & elf::VERSYM_HIDDEN != 0
+    }
+}
+
+/// A version definition or requirement.
+///
+/// This is derived from entries in the [`elf::SHT_GNU_VERDEF`] and [`elf::SHT_GNU_VERNEED`] sections.
+#[derive(Debug, Default, Clone, Copy)]
+pub struct Version<'data> {
+    name: &'data [u8],
+    hash: u32,
+    // Used to keep track of valid indices in `VersionTable`.
+    valid: bool,
+}
+
+impl<'data> Version<'data> {
+    /// Return the version name.
+    pub fn name(&self) -> &'data [u8] {
+        self.name
+    }
+
+    /// Return hash of the version name.
+    pub fn hash(&self) -> u32 {
+        self.hash
+    }
+}
+
+/// A table of version definitions and requirements.
+///
+/// It allows looking up the version information for a given symbol index.
+///
+/// This is derived from entries in the [`elf::SHT_GNU_VERSYM`], [`elf::SHT_GNU_VERDEF`]
+/// and [`elf::SHT_GNU_VERNEED`] sections.
+///
+/// Returned by [`SectionTable::versions`](super::SectionTable::versions).
+#[derive(Debug, Clone)]
+pub struct VersionTable<'data, Elf: FileHeader> {
+    symbols: &'data [elf::Versym<Elf::Endian>],
+    versions: Vec<Version<'data>>,
+}
+
+impl<'data, Elf: FileHeader> Default for VersionTable<'data, Elf> {
+    fn default() -> Self {
+        VersionTable {
+            symbols: &[],
+            versions: Vec::new(),
+        }
+    }
+}
+
+impl<'data, Elf: FileHeader> VersionTable<'data, Elf> {
+    /// Parse the version sections.
+    pub fn parse<R: ReadRef<'data>>(
+        endian: Elf::Endian,
+        versyms: &'data [elf::Versym<Elf::Endian>],
+        verdefs: Option<VerdefIterator<'data, Elf>>,
+        verneeds: Option<VerneedIterator<'data, Elf>>,
+        strings: StringTable<'data, R>,
+    ) -> Result<Self> {
+        let mut max_index = 0;
+        if let Some(mut verdefs) = verdefs.clone() {
+            while let Some((verdef, _)) = verdefs.next()? {
+                if verdef.vd_flags.get(endian) & elf::VER_FLG_BASE != 0 {
+                    continue;
+                }
+                let index = verdef.vd_ndx.get(endian) & elf::VERSYM_VERSION;
+                if max_index < index {
+                    max_index = index;
+                }
+            }
+        }
+        if let Some(mut verneeds) = verneeds.clone() {
+            while let Some((_, mut vernauxs)) = verneeds.next()? {
+                while let Some(vernaux) = vernauxs.next()? {
+                    let index = vernaux.vna_other.get(endian) & elf::VERSYM_VERSION;
+                    if max_index < index {
+                        max_index = index;
+                    }
+                }
+            }
+        }
+
+        // Indices should be sequential, but this could be up to
+        // 32k * size_of::<Version>() if max_index is bad.
+        let mut versions = vec![Version::default(); max_index as usize + 1];
+
+        if let Some(mut verdefs) = verdefs {
+            while let Some((verdef, mut verdauxs)) = verdefs.next()? {
+                if verdef.vd_flags.get(endian) & elf::VER_FLG_BASE != 0 {
+                    continue;
+                }
+                let index = verdef.vd_ndx.get(endian) & elf::VERSYM_VERSION;
+                if index <= elf::VER_NDX_GLOBAL {
+                    // TODO: return error?
+                    continue;
+                }
+                if let Some(verdaux) = verdauxs.next()? {
+                    versions[usize::from(index)] = Version {
+                        name: verdaux.name(endian, strings)?,
+                        hash: verdef.vd_hash.get(endian),
+                        valid: true,
+                    };
+                }
+            }
+        }
+        if let Some(mut verneeds) = verneeds {
+            while let Some((_, mut vernauxs)) = verneeds.next()? {
+                while let Some(vernaux) = vernauxs.next()? {
+                    let index = vernaux.vna_other.get(endian) & elf::VERSYM_VERSION;
+                    if index <= elf::VER_NDX_GLOBAL {
+                        // TODO: return error?
+                        continue;
+                    }
+                    versions[usize::from(index)] = Version {
+                        name: vernaux.name(endian, strings)?,
+                        hash: vernaux.vna_hash.get(endian),
+                        valid: true,
+                    };
+                }
+            }
+        }
+
+        Ok(VersionTable {
+            symbols: versyms,
+            versions,
+        })
+    }
+
+    /// Return true if the version table is empty.
+    pub fn is_empty(&self) -> bool {
+        self.symbols.is_empty()
+    }
+
+    /// Return version index for a given symbol index.
+    pub fn version_index(&self, endian: Elf::Endian, index: usize) -> VersionIndex {
+        let version_index = match self.symbols.get(index) {
+            Some(x) => x.0.get(endian),
+            // Ideally this would be VER_NDX_LOCAL for undefined symbols,
+            // but currently there are no checks that need this distinction.
+            None => elf::VER_NDX_GLOBAL,
+        };
+        VersionIndex(version_index)
+    }
+
+    /// Return version information for a given symbol version index.
+    ///
+    /// Returns `Ok(None)` for local and global versions.
+    /// Returns `Err(_)` if index is invalid.
+    pub fn version(&self, index: VersionIndex) -> Result<Option<&Version<'data>>> {
+        if index.index() <= elf::VER_NDX_GLOBAL {
+            return Ok(None);
+        }
+        self.versions
+            .get(usize::from(index.index()))
+            .filter(|version| version.valid)
+            .read_error("Invalid ELF symbol version index")
+            .map(Some)
+    }
+
+    /// Return true if the given symbol index satisfies the requirements of `need`.
+    ///
+    /// Returns false for any error.
+    ///
+    /// Note: this function hasn't been fully tested and is likely to be incomplete.
+    pub fn matches(&self, endian: Elf::Endian, index: usize, need: Option<&Version<'_>>) -> bool {
+        let version_index = self.version_index(endian, index);
+        let def = match self.version(version_index) {
+            Ok(def) => def,
+            Err(_) => return false,
+        };
+        match (def, need) {
+            (Some(def), Some(need)) => need.hash == def.hash && need.name == def.name,
+            (None, Some(_need)) => {
+                // Version must be present if needed.
+                false
+            }
+            (Some(_def), None) => {
+                // For a dlsym call, use the newest version.
+                // TODO: if not a dlsym call, then use the oldest version.
+                !version_index.is_hidden()
+            }
+            (None, None) => true,
+        }
+    }
+}
+
+/// An iterator for the entries in an ELF [`elf::SHT_GNU_VERDEF`] section.
+#[derive(Debug, Clone)]
+pub struct VerdefIterator<'data, Elf: FileHeader> {
+    endian: Elf::Endian,
+    data: Bytes<'data>,
+}
+
+impl<'data, Elf: FileHeader> VerdefIterator<'data, Elf> {
+    pub(super) fn new(endian: Elf::Endian, data: &'data [u8]) -> Self {
+        VerdefIterator {
+            endian,
+            data: Bytes(data),
+        }
+    }
+
+    /// Return the next `Verdef` entry.
+    pub fn next(
+        &mut self,
+    ) -> Result<Option<(&'data elf::Verdef<Elf::Endian>, VerdauxIterator<'data, Elf>)>> {
+        if self.data.is_empty() {
+            return Ok(None);
+        }
+
+        let verdef = self
+            .data
+            .read_at::<elf::Verdef<_>>(0)
+            .read_error("ELF verdef is too short")?;
+
+        let mut verdaux_data = self.data;
+        verdaux_data
+            .skip(verdef.vd_aux.get(self.endian) as usize)
+            .read_error("Invalid ELF vd_aux")?;
+        let verdaux =
+            VerdauxIterator::new(self.endian, verdaux_data.0, verdef.vd_cnt.get(self.endian));
+
+        let next = verdef.vd_next.get(self.endian);
+        if next != 0 {
+            self.data
+                .skip(next as usize)
+                .read_error("Invalid ELF vd_next")?;
+        } else {
+            self.data = Bytes(&[]);
+        }
+        Ok(Some((verdef, verdaux)))
+    }
+}
+
+/// An iterator for the auxiliary records for an entry in an ELF [`elf::SHT_GNU_VERDEF`] section.
+#[derive(Debug, Clone)]
+pub struct VerdauxIterator<'data, Elf: FileHeader> {
+    endian: Elf::Endian,
+    data: Bytes<'data>,
+    count: u16,
+}
+
+impl<'data, Elf: FileHeader> VerdauxIterator<'data, Elf> {
+    pub(super) fn new(endian: Elf::Endian, data: &'data [u8], count: u16) -> Self {
+        VerdauxIterator {
+            endian,
+            data: Bytes(data),
+            count,
+        }
+    }
+
+    /// Return the next `Verdaux` entry.
+    pub fn next(&mut self) -> Result<Option<&'data elf::Verdaux<Elf::Endian>>> {
+        if self.count == 0 {
+            return Ok(None);
+        }
+
+        let verdaux = self
+            .data
+            .read_at::<elf::Verdaux<_>>(0)
+            .read_error("ELF verdaux is too short")?;
+
+        self.data
+            .skip(verdaux.vda_next.get(self.endian) as usize)
+            .read_error("Invalid ELF vda_next")?;
+        self.count -= 1;
+        Ok(Some(verdaux))
+    }
+}
+
+/// An iterator for the entries in an ELF [`elf::SHT_GNU_VERNEED`] section.
+#[derive(Debug, Clone)]
+pub struct VerneedIterator<'data, Elf: FileHeader> {
+    endian: Elf::Endian,
+    data: Bytes<'data>,
+}
+
+impl<'data, Elf: FileHeader> VerneedIterator<'data, Elf> {
+    pub(super) fn new(endian: Elf::Endian, data: &'data [u8]) -> Self {
+        VerneedIterator {
+            endian,
+            data: Bytes(data),
+        }
+    }
+
+    /// Return the next `Verneed` entry.
+    pub fn next(
+        &mut self,
+    ) -> Result<
+        Option<(
+            &'data elf::Verneed<Elf::Endian>,
+            VernauxIterator<'data, Elf>,
+        )>,
+    > {
+        if self.data.is_empty() {
+            return Ok(None);
+        }
+
+        let verneed = self
+            .data
+            .read_at::<elf::Verneed<_>>(0)
+            .read_error("ELF verneed is too short")?;
+
+        let mut vernaux_data = self.data;
+        vernaux_data
+            .skip(verneed.vn_aux.get(self.endian) as usize)
+            .read_error("Invalid ELF vn_aux")?;
+        let vernaux =
+            VernauxIterator::new(self.endian, vernaux_data.0, verneed.vn_cnt.get(self.endian));
+
+        let next = verneed.vn_next.get(self.endian);
+        if next != 0 {
+            self.data
+                .skip(next as usize)
+                .read_error("Invalid ELF vn_next")?;
+        } else {
+            self.data = Bytes(&[]);
+        }
+        Ok(Some((verneed, vernaux)))
+    }
+}
+
+/// An iterator for the auxiliary records for an entry in an ELF [`elf::SHT_GNU_VERNEED`] section.
+#[derive(Debug, Clone)]
+pub struct VernauxIterator<'data, Elf: FileHeader> {
+    endian: Elf::Endian,
+    data: Bytes<'data>,
+    count: u16,
+}
+
+impl<'data, Elf: FileHeader> VernauxIterator<'data, Elf> {
+    pub(super) fn new(endian: Elf::Endian, data: &'data [u8], count: u16) -> Self {
+        VernauxIterator {
+            endian,
+            data: Bytes(data),
+            count,
+        }
+    }
+
+    /// Return the next `Vernaux` entry.
+    pub fn next(&mut self) -> Result<Option<&'data elf::Vernaux<Elf::Endian>>> {
+        if self.count == 0 {
+            return Ok(None);
+        }
+
+        let vernaux = self
+            .data
+            .read_at::<elf::Vernaux<_>>(0)
+            .read_error("ELF vernaux is too short")?;
+
+        self.data
+            .skip(vernaux.vna_next.get(self.endian) as usize)
+            .read_error("Invalid ELF vna_next")?;
+        self.count -= 1;
+        Ok(Some(vernaux))
+    }
+}
+
+impl<Endian: endian::Endian> elf::Verdaux<Endian> {
+    /// Parse the version name from the string table.
+    pub fn name<'data, R: ReadRef<'data>>(
+        &self,
+        endian: Endian,
+        strings: StringTable<'data, R>,
+    ) -> Result<&'data [u8]> {
+        strings
+            .get(self.vda_name.get(endian))
+            .read_error("Invalid ELF vda_name")
+    }
+}
+
+impl<Endian: endian::Endian> elf::Verneed<Endian> {
+    /// Parse the file from the string table.
+    pub fn file<'data, R: ReadRef<'data>>(
+        &self,
+        endian: Endian,
+        strings: StringTable<'data, R>,
+    ) -> Result<&'data [u8]> {
+        strings
+            .get(self.vn_file.get(endian))
+            .read_error("Invalid ELF vn_file")
+    }
+}
+
+impl<Endian: endian::Endian> elf::Vernaux<Endian> {
+    /// Parse the version name from the string table.
+    pub fn name<'data, R: ReadRef<'data>>(
+        &self,
+        endian: Endian,
+        strings: StringTable<'data, R>,
+    ) -> Result<&'data [u8]> {
+        strings
+            .get(self.vna_name.get(endian))
+            .read_error("Invalid ELF vna_name")
+    }
+}