sys: push error construction up

aya/src/maps/mod.rs

@@ -560,10 +560,7 @@ impl MapData {
             io_error,
         })? as RawFd;
 
-        let info = bpf_map_get_info_by_fd(fd).map_err(|io_error| SyscallError {
-            call: "BPF_MAP_GET_INFO_BY_FD",
-            io_error,
-        })?;
+        let info = bpf_map_get_info_by_fd(fd)?;
 
         Ok(MapData {
             obj: parse_map_info(info, PinningType::ByName),
@@ -579,10 +576,7 @@ impl MapData {
     /// This API is intended for cases where you have received a valid BPF FD from some other means.
     /// For example, you received an FD over Unix Domain Socket.
     pub fn from_fd(fd: RawFd) -> Result<MapData, MapError> {
-        let info = bpf_map_get_info_by_fd(fd).map_err(|io_error| SyscallError {
-            call: "BPF_OBJ_GET",
-            io_error,
-        })?;
+        let info = bpf_map_get_info_by_fd(fd)?;
 
         Ok(MapData {
             obj: parse_map_info(info, PinningType::None),

aya/src/programs/extension.rs

@@ -151,10 +151,7 @@ impl Extension {
 /// with the name `func_name` within that BTF object.
 fn get_btf_info(prog_fd: i32, func_name: &str) -> Result<(RawFd, u32), ProgramError> {
     // retrieve program information
-    let info = sys::bpf_prog_get_info_by_fd(prog_fd).map_err(|io_error| SyscallError {
-        call: "bpf_prog_get_info_by_fd",
-        io_error,
-    })?;
+    let info = sys::bpf_prog_get_info_by_fd(prog_fd)?;
 
     // btf_id refers to the ID of the program btf that was loaded with bpf(BPF_BTF_LOAD)
     if info.btf_id == 0 {

aya/src/programs/kprobe.rs

@@ -10,7 +10,7 @@ use crate::{
         probe::{attach, ProbeKind},
         FdLink, LinkError, ProgramData, ProgramError,
     },
-    sys::{bpf_link_get_info_by_fd, SyscallError},
+    sys::bpf_link_get_info_by_fd,
     VerifierLogLevel,
 };
 
@@ -137,10 +137,7 @@ impl TryFrom<FdLink> for KProbeLink {
     type Error = LinkError;
 
     fn try_from(fd_link: FdLink) -> Result<Self, Self::Error> {
-        let info = bpf_link_get_info_by_fd(fd_link.fd).map_err(|io_error| SyscallError {
-            call: "BPF_OBJ_GET_INFO_BY_FD",
-            io_error,
-        })?;
+        let info = bpf_link_get_info_by_fd(fd_link.fd)?;
         if info.type_ == (bpf_link_type::BPF_LINK_TYPE_KPROBE_MULTI as u32) {
             return Ok(KProbeLink::new(PerfLinkInner::FdLink(fd_link)));
         }

aya/src/programs/lirc_mode2.rs

@@ -99,11 +99,7 @@ impl LircMode2 {
         let mut prog_fds = Vec::with_capacity(prog_ids.len());
 
         for id in prog_ids {
-            let fd = bpf_prog_get_fd_by_id(id).map_err(|io_error| SyscallError {
-                call: "bpf_prog_get_fd_by_id",
-                io_error,
-            })?;
-
+            let fd = bpf_prog_get_fd_by_id(id)?;
             prog_fds.push(fd);
         }
 
@@ -137,13 +133,7 @@ impl LircLink {
     pub fn info(&self) -> Result<ProgramInfo, ProgramError> {
         bpf_prog_get_info_by_fd(self.prog_fd)
             .map(ProgramInfo)
-            .map_err(|io_error| {
-                SyscallError {
-                    call: "bpf_prog_get_info_by_fd",
-                    io_error,
-                }
-                .into()
-            })
+            .map_err(Into::into)
     }
 }
 

aya/src/programs/mod.rs

@@ -487,11 +487,7 @@ impl<T: Link> ProgramData<T> {
             io_error,
         })? as RawFd;
 
-        let info = bpf_prog_get_info_by_fd(fd).map_err(|io_error| SyscallError {
-            call: "bpf_prog_get_info_by_fd",
-            io_error,
-        })?;
-
+        let info = bpf_prog_get_info_by_fd(fd)?;
         let name = ProgramInfo(info).name_as_str().map(|s| s.to_string());
         ProgramData::from_bpf_prog_info(name, fd, path.as_ref(), info, verifier_log_level)
     }
@@ -945,10 +941,8 @@ impl ProgramInfo {
     ///
     /// The returned fd must be closed when no longer needed.
     pub fn fd(&self) -> Result<RawFd, ProgramError> {
-        let fd = bpf_prog_get_fd_by_id(self.0.id).map_err(|io_error| SyscallError {
-            call: "bpf_prog_get_fd_by_id",
-            io_error,
-        })?;
+        let Self(info) = self;
+        let fd = bpf_prog_get_fd_by_id(info.id)?;
         Ok(fd.into_raw_fd())
     }
 
@@ -960,10 +954,7 @@ impl ProgramInfo {
             io_error,
         })? as RawFd;
 
-        let info = bpf_prog_get_info_by_fd(fd).map_err(|io_error| SyscallError {
-            call: "bpf_prog_get_info_by_fd",
-            io_error,
-        })?;
+        let info = bpf_prog_get_info_by_fd(fd)?;
         unsafe {
             libc::close(fd);
         }
@@ -998,17 +989,11 @@ pub fn loaded_programs() -> impl Iterator<Item = Result<ProgramInfo, ProgramErro
     iter_prog_ids()
         .map(|id| {
             let id = id?;
-            bpf_prog_get_fd_by_id(id).map_err(|io_error| SyscallError {
-                call: "bpf_prog_get_fd_by_id",
-                io_error,
-            })
+            bpf_prog_get_fd_by_id(id)
         })
         .map(|fd| {
             let fd = fd?;
-            bpf_prog_get_info_by_fd(fd.as_raw_fd()).map_err(|io_error| SyscallError {
-                call: "bpf_prog_get_info_by_fd",
-                io_error,
-            })
+            bpf_prog_get_info_by_fd(fd.as_raw_fd())
         })
         .map(|result| result.map(ProgramInfo).map_err(Into::into))
 }

aya/src/programs/perf_event.rs

@@ -206,10 +206,7 @@ impl TryFrom<FdLink> for PerfEventLink {
     type Error = LinkError;
 
     fn try_from(fd_link: FdLink) -> Result<Self, Self::Error> {
-        let info = bpf_link_get_info_by_fd(fd_link.fd).map_err(|io_error| SyscallError {
-            call: "BPF_OBJ_GET_INFO_BY_FD",
-            io_error,
-        })?;
+        let info = bpf_link_get_info_by_fd(fd_link.fd)?;
         if info.type_ == (bpf_link_type::BPF_LINK_TYPE_PERF_EVENT as u32) {
             return Ok(PerfEventLink::new(PerfLinkInner::FdLink(fd_link)));
         }

aya/src/programs/trace_point.rs

@@ -131,10 +131,7 @@ impl TryFrom<FdLink> for TracePointLink {
     type Error = LinkError;
 
     fn try_from(fd_link: FdLink) -> Result<Self, Self::Error> {
-        let info = bpf_link_get_info_by_fd(fd_link.fd).map_err(|io_error| SyscallError {
-            call: "BPF_OBJ_GET_INFO_BY_FD",
-            io_error,
-        })?;
+        let info = bpf_link_get_info_by_fd(fd_link.fd)?;
         if info.type_ == (bpf_link_type::BPF_LINK_TYPE_TRACING as u32) {
             return Ok(TracePointLink::new(PerfLinkInner::FdLink(fd_link)));
         }

aya/src/programs/uprobe.rs

@@ -21,7 +21,7 @@ use crate::{
         probe::{attach, ProbeKind},
         FdLink, LinkError, ProgramData, ProgramError,
     },
-    sys::{bpf_link_get_info_by_fd, SyscallError},
+    sys::bpf_link_get_info_by_fd,
     VerifierLogLevel,
 };
 
@@ -177,10 +177,7 @@ impl TryFrom<FdLink> for UProbeLink {
     type Error = LinkError;
 
     fn try_from(fd_link: FdLink) -> Result<Self, Self::Error> {
-        let info = bpf_link_get_info_by_fd(fd_link.fd).map_err(|io_error| SyscallError {
-            call: "BPF_OBJ_GET_INFO_BY_FD",
-            io_error,
-        })?;
+        let info = bpf_link_get_info_by_fd(fd_link.fd)?;
         if info.type_ == (bpf_link_type::BPF_LINK_TYPE_TRACING as u32) {
             return Ok(UProbeLink::new(PerfLinkInner::FdLink(fd_link)));
         }

aya/src/programs/xdp.rs

@@ -279,10 +279,7 @@ impl TryFrom<FdLink> for XdpLink {
 
     fn try_from(fd_link: FdLink) -> Result<Self, Self::Error> {
         // unwrap of fd_link.fd will not panic since it's only None when being dropped.
-        let info = bpf_link_get_info_by_fd(fd_link.fd).map_err(|io_error| SyscallError {
-            call: "BPF_OBJ_GET_INFO_BY_FD",
-            io_error,
-        })?;
+        let info = bpf_link_get_info_by_fd(fd_link.fd)?;
         if info.type_ == (bpf_link_type::BPF_LINK_TYPE_XDP as u32) {
             return Ok(XdpLink::new(XdpLinkInner::FdLink(fd_link)));
         }

aya/src/sys/bpf.rs

@@ -460,57 +460,57 @@ pub(crate) fn bpf_prog_query(
     ret
 }
 
-pub(crate) fn bpf_prog_get_fd_by_id(prog_id: u32) -> Result<OwnedFd, io::Error> {
+pub(crate) fn bpf_prog_get_fd_by_id(prog_id: u32) -> Result<OwnedFd, SyscallError> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     attr.__bindgen_anon_6.__bindgen_anon_1.prog_id = prog_id;
     // SAFETY: BPF_PROG_GET_FD_BY_ID returns a new file descriptor.
-    unsafe { fd_sys_bpf(bpf_cmd::BPF_PROG_GET_FD_BY_ID, &mut attr).map_err(|(_, e)| e) }
+    unsafe { fd_sys_bpf(bpf_cmd::BPF_PROG_GET_FD_BY_ID, &mut attr) }.map_err(|(code, io_error)| {
+        assert_eq!(code, -1);
+        SyscallError {
+            call: "bpf_prog_get_fd_by_id",
+            io_error,
+        }
+    })
 }
 
-pub(crate) fn bpf_prog_get_info_by_fd(prog_fd: RawFd) -> Result<bpf_prog_info, io::Error> {
+fn bpf_obj_get_info_by_fd<T>(fd: BorrowedFd<'_>) -> Result<T, SyscallError> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
     // info gets entirely populated by the kernel
     let info = MaybeUninit::zeroed();
 
-    attr.info.bpf_fd = prog_fd as u32;
+    attr.info.bpf_fd = fd.as_raw_fd() as u32;
     attr.info.info = &info as *const _ as u64;
-    attr.info.info_len = mem::size_of::<bpf_prog_info>() as u32;
+    attr.info.info_len = mem::size_of_val(&info) as u32;
 
     match sys_bpf(bpf_cmd::BPF_OBJ_GET_INFO_BY_FD, &mut attr) {
-        Ok(_) => Ok(unsafe { info.assume_init() }),
-        Err((_, err)) => Err(err),
+        Ok(code) => {
+            assert_eq!(code, 0);
+            Ok(unsafe { info.assume_init() })
+        }
+        Err((code, io_error)) => {
+            assert_eq!(code, -1);
+            Err(SyscallError {
+                call: "bpf_obj_get_info_by_fd",
+                io_error,
+            })
+        }
     }
 }
 
-pub(crate) fn bpf_map_get_info_by_fd(prog_fd: RawFd) -> Result<bpf_map_info, io::Error> {
-    let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
-    // info gets entirely populated by the kernel
-    let info = MaybeUninit::zeroed();
-
-    attr.info.bpf_fd = prog_fd as u32;
-    attr.info.info = info.as_ptr() as *const _ as u64;
-    attr.info.info_len = mem::size_of::<bpf_map_info>() as u32;
-
-    match sys_bpf(bpf_cmd::BPF_OBJ_GET_INFO_BY_FD, &mut attr) {
-        Ok(_) => Ok(unsafe { info.assume_init() }),
-        Err((_, err)) => Err(err),
-    }
+pub(crate) fn bpf_prog_get_info_by_fd(fd: RawFd) -> Result<bpf_prog_info, SyscallError> {
+    let fd = unsafe { BorrowedFd::borrow_raw(fd) };
+    bpf_obj_get_info_by_fd::<bpf_prog_info>(fd)
 }
 
-pub(crate) fn bpf_link_get_info_by_fd(link_fd: RawFd) -> Result<bpf_link_info, io::Error> {
-    let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
-    // info gets entirely populated by the kernel
-    let info = unsafe { MaybeUninit::zeroed().assume_init() };
-
-    attr.info.bpf_fd = link_fd as u32;
-    attr.info.info = &info as *const _ as u64;
-    attr.info.info_len = mem::size_of::<bpf_link_info>() as u32;
+pub(crate) fn bpf_map_get_info_by_fd(fd: RawFd) -> Result<bpf_map_info, SyscallError> {
+    let fd = unsafe { BorrowedFd::borrow_raw(fd) };
+    bpf_obj_get_info_by_fd::<bpf_map_info>(fd)
+}
 
-    match sys_bpf(bpf_cmd::BPF_OBJ_GET_INFO_BY_FD, &mut attr) {
-        Ok(_) => Ok(info),
-        Err((_, err)) => Err(err),
-    }
+pub(crate) fn bpf_link_get_info_by_fd(fd: RawFd) -> Result<bpf_link_info, SyscallError> {
+    let fd = unsafe { BorrowedFd::borrow_raw(fd) };
+    bpf_obj_get_info_by_fd::<bpf_link_info>(fd)
 }
 
 pub(crate) fn btf_obj_get_info_by_fd(