Merge pull request #642 from aya-rs/less-strings

aya: don't allocate static strings

aya-bpf-macros/src/expand.rs

@@ -93,7 +93,7 @@ impl Map {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = "maps".to_string();
+        let section_name = "maps";
         let name = &self.name;
         let item = &self.item;
         Ok(quote! {
@@ -148,10 +148,10 @@ impl SockOps {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = if let Some(name) = &self.name {
-            format!("sockops/{name}")
+        let section_name: std::borrow::Cow<'_, _> = if let Some(name) = &self.name {
+            format!("sockops/{name}").into()
         } else {
-            "sockops".to_owned()
+            "sockops".into()
         };
         let fn_vis = &self.item.vis;
         let fn_name = &self.item.sig.ident;
@@ -256,10 +256,10 @@ impl SchedClassifier {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = if let Some(name) = &self.name {
-            format!("classifier/{name}")
+        let section_name: std::borrow::Cow<'_, _> = if let Some(name) = &self.name {
+            format!("classifier/{name}").into()
         } else {
-            "classifier".to_owned()
+            "classifier".into()
         };
         let fn_vis = &self.item.vis;
         let fn_name = &self.item.sig.ident;
@@ -452,16 +452,16 @@ impl CgroupSock {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = if let Some(name) = &self.name {
+        let section_name: std::borrow::Cow<'_, _> = if let Some(name) = &self.name {
             if let Some(attach_type) = &self.attach_type {
-                format!("cgroup/{attach_type}/{name}")
+                format!("cgroup/{attach_type}/{name}").into()
             } else {
-                format!("cgroup/sock/{name}")
+                format!("cgroup/sock/{name}").into()
             }
         } else if let Some(attach_type) = &self.attach_type {
-            format!("cgroup/{attach_type}")
+            format!("cgroup/{attach_type}").into()
         } else {
-            "cgroup/sock".to_string()
+            "cgroup/sock".into()
         };
         let fn_vis = &self.item.vis;
         let fn_name = &self.item.sig.ident;
@@ -761,10 +761,10 @@ impl SocketFilter {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = if let Some(name) = &self.name {
-            format!("socket/{name}")
+        let section_name: std::borrow::Cow<'_, _> = if let Some(name) = &self.name {
+            format!("socket/{name}").into()
         } else {
-            "socket".to_owned()
+            "socket".into()
         };
         let fn_vis = &self.item.vis;
         let fn_name = &self.item.sig.ident;
@@ -854,10 +854,10 @@ impl SkLookup {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = if let Some(name) = &self.name {
-            format!("sk_lookup/{name}")
+        let section_name: std::borrow::Cow<'_, _> = if let Some(name) = &self.name {
+            format!("sk_lookup/{name}").into()
         } else {
-            "sk_lookup".to_owned()
+            "sk_lookup".into()
         };
         let fn_vis = &self.item.vis;
         let fn_name = &self.item.sig.ident;
@@ -887,10 +887,10 @@ impl CgroupDevice {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = if let Some(name) = &self.name {
-            format!("cgroup/dev/{name}")
+        let section_name: std::borrow::Cow<'_, _> = if let Some(name) = &self.name {
+            format!("cgroup/dev/{name}").into()
         } else {
-            ("cgroup/dev").to_owned()
+            "cgroup/dev".into()
         };
         let fn_vis = &self.item.vis;
         let fn_name = &self.item.sig.ident;

aya-obj/src/btf/btf.rs

@@ -1,10 +1,9 @@
 use core::{ffi::CStr, mem, ptr};
 
 use alloc::{
-    borrow::Cow,
-    ffi::CString,
+    borrow::{Cow, ToOwned as _},
     format,
-    string::{String, ToString},
+    string::String,
     vec,
     vec::Vec,
 };
@@ -276,10 +275,10 @@ impl Btf {
     }
 
     /// Adds a string to BTF metadata, returning an offset
-    pub fn add_string(&mut self, name: String) -> u32 {
-        let str = CString::new(name).unwrap();
+    pub fn add_string(&mut self, name: &str) -> u32 {
+        let str = name.bytes().chain(std::iter::once(0));
         let name_offset = self.strings.len();
-        self.strings.extend(str.as_c_str().to_bytes_with_nul());
+        self.strings.extend(str);
         self.header.str_len = self.strings.len() as u32;
         name_offset as u32
     }
@@ -424,7 +423,7 @@ impl Btf {
         }
 
         Err(BtfError::UnknownBtfTypeName {
-            type_name: name.to_string(),
+            type_name: name.to_owned(),
         })
     }
 
@@ -498,14 +497,13 @@ impl Btf {
 
                     // STRUCT aren't allowed to have "." in their name, fixup this if needed.
                     let mut name_offset = t.name_offset();
-                    let sec_name = self.string_at(name_offset)?;
-                    let name = sec_name.to_string();
+                    let name = self.string_at(name_offset)?;
 
                     // Handle any "." characters in struct names
                     // Example: ".maps"
                     let fixed_name = name.replace('.', "_");
                     if fixed_name != name {
-                        name_offset = self.add_string(fixed_name);
+                        name_offset = self.add_string(&fixed_name);
                     }
 
                     let mut members = vec![];
@@ -526,8 +524,8 @@ impl Btf {
                 // we need to fix them here before loading the btf to the kernel
                 BtfType::DataSec(d) if features.btf_datasec => {
                     // Start DataSec Fixups
-                    let sec_name = self.string_at(d.name_offset)?;
-                    let name = sec_name.to_string();
+                    let name = self.string_at(d.name_offset)?;
+                    let name = name.into_owned();
 
                     let mut fixed_ty = d.clone();
 
@@ -535,7 +533,7 @@ impl Btf {
                     // Example: "maps/hashmap"
                     let fixed_name = name.replace('/', ".");
                     if fixed_name != name {
-                        fixed_ty.name_offset = self.add_string(fixed_name);
+                        fixed_ty.name_offset = self.add_string(&fixed_name);
                     }
 
                     // There are some cases when the compiler does indeed populate the
@@ -546,11 +544,12 @@ impl Btf {
                         // We need to get the size of the section from the ELF file
                         // Fortunately, we cached these when parsing it initially
                         // and we can this up by name in section_infos
-                        let (_, size) = section_infos.get(&name).ok_or_else(|| {
-                            BtfError::UnknownSectionSize {
-                                section_name: name.clone(),
+                        let size = match section_infos.get(&name) {
+                            Some((_, size)) => size,
+                            None => {
+                                return Err(BtfError::UnknownSectionSize { section_name: name });
                             }
-                        })?;
+                        };
                         debug!("{} {}: fixup size to {}", kind, name, size);
                         fixed_ty.size = *size as u32;
 
@@ -563,7 +562,7 @@ impl Btf {
                             let var_type = types.type_by_id(d.btf_type)?;
                             let var_kind = var_type.kind();
                             if let BtfType::Var(var) = var_type {
-                                let var_name = self.string_at(var.name_offset)?.to_string();
+                                let var_name = self.string_at(var.name_offset)?;
                                 if var.linkage == VarLinkage::Static {
                                     debug!(
                                         "{} {}: {} {}: fixup not required",
@@ -572,11 +571,14 @@ impl Btf {
                                     continue;
                                 }
 
-                                let offset = symbol_offsets.get(&var_name).ok_or(
-                                    BtfError::SymbolOffsetNotFound {
-                                        symbol_name: var_name.clone(),
-                                    },
-                                )?;
+                                let offset = match symbol_offsets.get(var_name.as_ref()) {
+                                    Some(offset) => offset,
+                                    None => {
+                                        return Err(BtfError::SymbolOffsetNotFound {
+                                            symbol_name: var_name.into_owned(),
+                                        });
+                                    }
+                                };
                                 d.offset = *offset as u32;
                                 debug!(
                                     "{} {}: {} {}: fixup offset {}",
@@ -594,7 +596,7 @@ impl Btf {
                     let mut ty = ty.clone();
                     for (i, param) in ty.params.iter_mut().enumerate() {
                         if param.name_offset == 0 && param.btf_type != 0 {
-                            param.name_offset = self.add_string(format!("param{i}"));
+                            param.name_offset = self.add_string(&format!("param{i}"));
                         }
                     }
                     types.types[i] = BtfType::FuncProto(ty);
@@ -1163,11 +1165,11 @@ mod tests {
     #[test]
     fn test_write_btf() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
         btf.add_type(int_type);
 
-        let name_offset = btf.add_string("widget".to_string());
+        let name_offset = btf.add_string("widget");
         let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
         btf.add_type(int_type);
 
@@ -1189,7 +1191,7 @@ mod tests {
     #[test]
     fn test_fixup_ptr() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1197,7 +1199,7 @@ mod tests {
             0,
         )));
 
-        let name_offset = btf.add_string("&mut int".to_string());
+        let name_offset = btf.add_string("&mut int");
         let ptr_type_id = btf.add_type(BtfType::Ptr(Ptr::new(name_offset, int_type_id)));
 
         let features = Default::default();
@@ -1221,7 +1223,7 @@ mod tests {
     #[test]
     fn test_sanitize_var() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1229,7 +1231,7 @@ mod tests {
             0,
         )));
 
-        let name_offset = btf.add_string("&mut int".to_string());
+        let name_offset = btf.add_string("&mut int");
         let var_type_id = btf.add_type(BtfType::Var(Var::new(
             name_offset,
             int_type_id,
@@ -1256,7 +1258,7 @@ mod tests {
     #[test]
     fn test_sanitize_datasec() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1264,14 +1266,14 @@ mod tests {
             0,
         )));
 
-        let name_offset = btf.add_string("foo".to_string());
+        let name_offset = btf.add_string("foo");
         let var_type_id = btf.add_type(BtfType::Var(Var::new(
             name_offset,
             int_type_id,
             VarLinkage::Static,
         )));
 
-        let name_offset = btf.add_string("data".to_string());
+        let name_offset = btf.add_string("data");
         let variables = vec![DataSecEntry {
             btf_type: var_type_id,
             offset: 0,
@@ -1303,7 +1305,7 @@ mod tests {
     #[test]
     fn test_fixup_datasec() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1311,14 +1313,14 @@ mod tests {
             0,
         )));
 
-        let name_offset = btf.add_string("foo".to_string());
+        let name_offset = btf.add_string("foo");
         let var_type_id = btf.add_type(BtfType::Var(Var::new(
             name_offset,
             int_type_id,
             VarLinkage::Global,
         )));
 
-        let name_offset = btf.add_string(".data/foo".to_string());
+        let name_offset = btf.add_string(".data/foo");
         let variables = vec![DataSecEntry {
             btf_type: var_type_id,
             offset: 0,
@@ -1333,8 +1335,8 @@ mod tests {
         };
 
         btf.fixup_and_sanitize(
-            &HashMap::from([(".data/foo".to_string(), (SectionIndex(0), 32u64))]),
-            &HashMap::from([("foo".to_string(), 64u64)]),
+            &HashMap::from([(".data/foo".to_owned(), (SectionIndex(0), 32u64))]),
+            &HashMap::from([("foo".to_owned(), 64u64)]),
             &features,
         )
         .unwrap();
@@ -1361,7 +1363,7 @@ mod tests {
     #[test]
     fn test_sanitize_func_and_proto() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1371,17 +1373,17 @@ mod tests {
 
         let params = vec![
             BtfParam {
-                name_offset: btf.add_string("a".to_string()),
+                name_offset: btf.add_string("a"),
                 btf_type: int_type_id,
             },
             BtfParam {
-                name_offset: btf.add_string("b".to_string()),
+                name_offset: btf.add_string("b"),
                 btf_type: int_type_id,
             },
         ];
         let func_proto_type_id =
             btf.add_type(BtfType::FuncProto(FuncProto::new(params, int_type_id)));
-        let inc = btf.add_string("inc".to_string());
+        let inc = btf.add_string("inc");
         let func_type_id = btf.add_type(BtfType::Func(Func::new(
             inc,
             func_proto_type_id,
@@ -1420,7 +1422,7 @@ mod tests {
     #[test]
     fn test_fixup_func_proto() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
         let int_type_id = btf.add_type(int_type);
 
@@ -1459,7 +1461,7 @@ mod tests {
     #[test]
     fn test_sanitize_func_global() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1469,17 +1471,17 @@ mod tests {
 
         let params = vec![
             BtfParam {
-                name_offset: btf.add_string("a".to_string()),
+                name_offset: btf.add_string("a"),
                 btf_type: int_type_id,
             },
             BtfParam {
-                name_offset: btf.add_string("b".to_string()),
+                name_offset: btf.add_string("b"),
                 btf_type: int_type_id,
             },
         ];
         let func_proto_type_id =
             btf.add_type(BtfType::FuncProto(FuncProto::new(params, int_type_id)));
-        let inc = btf.add_string("inc".to_string());
+        let inc = btf.add_string("inc");
         let func_type_id = btf.add_type(BtfType::Func(Func::new(
             inc,
             func_proto_type_id,
@@ -1508,7 +1510,7 @@ mod tests {
     #[test]
     fn test_sanitize_mem_builtins() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1518,11 +1520,11 @@ mod tests {
 
         let params = vec![
             BtfParam {
-                name_offset: btf.add_string("a".to_string()),
+                name_offset: btf.add_string("a"),
                 btf_type: int_type_id,
             },
             BtfParam {
-                name_offset: btf.add_string("b".to_string()),
+                name_offset: btf.add_string("b"),
                 btf_type: int_type_id,
             },
         ];
@@ -1531,7 +1533,7 @@ mod tests {
 
         let builtins = ["memset", "memcpy", "memcmp", "memmove"];
         for fname in builtins {
-            let func_name_offset = btf.add_string(fname.to_string());
+            let func_name_offset = btf.add_string(fname);
             let func_type_id = btf.add_type(BtfType::Func(Func::new(
                 func_name_offset,
                 func_proto_type_id,
@@ -1562,7 +1564,7 @@ mod tests {
     #[test]
     fn test_sanitize_float() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("float".to_string());
+        let name_offset = btf.add_string("float");
         let float_type_id = btf.add_type(BtfType::Float(Float::new(name_offset, 16)));
 
         let features = BtfFeatures {
@@ -1586,7 +1588,7 @@ mod tests {
     #[test]
     fn test_sanitize_decl_tag() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let int_type_id = btf.add_type(BtfType::Int(Int::new(
             name_offset,
             4,
@@ -1594,14 +1596,14 @@ mod tests {
             0,
         )));
 
-        let name_offset = btf.add_string("foo".to_string());
+        let name_offset = btf.add_string("foo");
         let var_type_id = btf.add_type(BtfType::Var(Var::new(
             name_offset,
             int_type_id,
             VarLinkage::Static,
         )));
 
-        let name_offset = btf.add_string("decl_tag".to_string());
+        let name_offset = btf.add_string("decl_tag");
         let decl_tag_type_id =
             btf.add_type(BtfType::DeclTag(DeclTag::new(name_offset, var_type_id, -1)));
 
@@ -1629,7 +1631,7 @@ mod tests {
 
         let int_type_id = btf.add_type(BtfType::Int(Int::new(0, 4, IntEncoding::Signed, 0)));
 
-        let name_offset = btf.add_string("int".to_string());
+        let name_offset = btf.add_string("int");
         let type_tag_type = btf.add_type(BtfType::TypeTag(TypeTag::new(name_offset, int_type_id)));
         btf.add_type(BtfType::Ptr(Ptr::new(0, type_tag_type)));
 

aya-obj/src/btf/relocation.rs

@@ -1,7 +1,7 @@
 use core::{mem, ops::Bound::Included, ptr};
 
 use alloc::{
-    borrow::ToOwned,
+    borrow::{Cow, ToOwned as _},
     collections::BTreeMap,
     format,
     string::{String, ToString},
@@ -99,7 +99,7 @@ enum RelocationError {
         /// The max index
         max_index: usize,
         /// The error message
-        error: String,
+        error: &'static str,
     },
 
     /// Relocation not valid for type
@@ -114,7 +114,7 @@ enum RelocationError {
         /// The type kind
         type_kind: String,
         /// The error message
-        error: String,
+        error: &'static str,
     },
 
     /// Invalid instruction referenced by relocation
@@ -127,7 +127,7 @@ enum RelocationError {
         /// The instruction index
         index: usize,
         /// The error message
-        error: String,
+        error: Cow<'static, str>,
     },
 
     #[error("applying relocation `{kind:?}` missing target BTF info for type `{type_id}` at instruction #{ins_index}")]
@@ -142,8 +142,8 @@ enum RelocationError {
     BtfError(#[from] BtfError),
 }
 
-fn err_type_name(name: &Option<String>) -> String {
-    name.clone().unwrap_or_else(|| "[unknown name]".to_string())
+fn err_type_name(name: &Option<String>) -> &str {
+    name.as_deref().unwrap_or("[unknown name]")
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -717,7 +717,7 @@ impl<'a> AccessSpec<'a> {
                             spec: spec.to_string(),
                             index,
                             max_index: n_variants,
-                            error: "tried to access nonexistant enum variant".to_string(),
+                            error: "tried to access nonexistant enum variant",
                         });
                     }
                     let accessors = vec![Accessor {
@@ -740,7 +740,7 @@ impl<'a> AccessSpec<'a> {
                         relocation_number: relocation.number,
                         relocation_kind: format!("{:?}", relocation.kind),
                         type_kind: format!("{:?}", ty.kind()),
-                        error: "enum relocation on non-enum type".to_string(),
+                        error: "enum relocation on non-enum type",
                     })
                 }
             },
@@ -770,7 +770,7 @@ impl<'a> AccessSpec<'a> {
                                     spec: spec.to_string(),
                                     index,
                                     max_index: members.len(),
-                                    error: "out of bounds struct or union access".to_string(),
+                                    error: "out of bounds struct or union access",
                                 });
                             }
 
@@ -806,7 +806,7 @@ impl<'a> AccessSpec<'a> {
                                     spec: spec.to_string(),
                                     index,
                                     max_index: array.len as usize,
-                                    error: "array index out of bounds".to_string(),
+                                    error: "array index out of bounds",
                                 });
                             }
                             accessors.push(Accessor {
@@ -822,8 +822,7 @@ impl<'a> AccessSpec<'a> {
                                 relocation_number: relocation.number,
                                 relocation_kind: format!("{rel_kind:?}"),
                                 type_kind: format!("{:?}", ty.kind()),
-                                error: "field relocation on a type that doesn't have fields"
-                                    .to_string(),
+                                error: "field relocation on a type that doesn't have fields",
                             });
                         }
                     };
@@ -958,7 +957,7 @@ impl ComputedRelocation {
                     return Err(RelocationError::InvalidInstruction {
                         relocation_number: rel.number,
                         index: ins_index,
-                        error: format!("invalid src_reg={src_reg:x} expected {BPF_K:x}"),
+                        error: format!("invalid src_reg={src_reg:x} expected {BPF_K:x}").into(),
                     });
                 }
 
@@ -969,7 +968,8 @@ impl ComputedRelocation {
                     return Err(RelocationError::InvalidInstruction {
                         relocation_number: rel.number,
                         index: ins_index,
-                        error: format!("value `{target_value}` overflows 16 bits offset field"),
+                        error: format!("value `{target_value}` overflows 16 bits offset field")
+                            .into(),
                     });
                 }
 
@@ -994,7 +994,8 @@ impl ComputedRelocation {
                                     self.local.size,
                                     err_type_name(&target_btf.err_type_name(target_ty)),
                                     target.size,
-                                ),
+                                )
+                                .into(),
                             })
                         }
                     }
@@ -1008,7 +1009,7 @@ impl ComputedRelocation {
                             return Err(RelocationError::InvalidInstruction {
                                 relocation_number: rel.number,
                                 index: ins_index,
-                                error: format!("invalid target size {size}"),
+                                error: format!("invalid target size {size}").into(),
                             })
                         }
                     } as u8;
@@ -1031,7 +1032,7 @@ impl ComputedRelocation {
                 return Err(RelocationError::InvalidInstruction {
                     relocation_number: rel.number,
                     index: ins_index,
-                    error: format!("invalid instruction class {class:x}"),
+                    error: format!("invalid instruction class {class:x}").into(),
                 })
             }
         };
@@ -1128,7 +1129,7 @@ impl ComputedRelocation {
                         relocation_number: rel.number,
                         relocation_kind: format!("{rel_kind:?}"),
                         type_kind: format!("{:?}", ty.kind()),
-                        error: "invalid relocation kind for array type".to_string(),
+                        error: "invalid relocation kind for array type",
                     });
                 }
             };
@@ -1143,7 +1144,7 @@ impl ComputedRelocation {
                     relocation_number: rel.number,
                     relocation_kind: format!("{:?}", rel.kind),
                     type_kind: format!("{:?}", ty.kind()),
-                    error: "field relocation on a type that doesn't have fields".to_string(),
+                    error: "field relocation on a type that doesn't have fields",
                 });
             }
         };

aya-obj/src/btf/types.rs

@@ -1724,11 +1724,11 @@ mod tests {
     #[test]
     fn test_types_are_compatible() {
         let mut btf = Btf::new();
-        let name_offset = btf.add_string("u32".to_string());
+        let name_offset = btf.add_string("u32");
         let u32t = btf.add_type(BtfType::Int(Int::new(name_offset, 4, IntEncoding::None, 0)));
-        let name_offset = btf.add_string("u64".to_string());
+        let name_offset = btf.add_string("u64");
         let u64t = btf.add_type(BtfType::Int(Int::new(name_offset, 8, IntEncoding::None, 0)));
-        let name_offset = btf.add_string("widgets".to_string());
+        let name_offset = btf.add_string("widgets");
         let array_type = btf.add_type(BtfType::Array(Array::new(name_offset, u64t, u32t, 16)));
 
         assert!(types_are_compatible(&btf, u32t, &btf, u32t).unwrap());

aya-obj/src/obj.rs

@@ -2378,7 +2378,7 @@ mod tests {
     fn test_patch_map_data() {
         let mut obj = fake_obj();
         obj.maps.insert(
-            ".rodata".to_string(),
+            ".rodata".to_owned(),
             Map::Legacy(LegacyMap {
                 def: bpf_map_def {
                     map_type: BPF_MAP_TYPE_ARRAY as u32,
@@ -2400,7 +2400,7 @@ mod tests {
             Symbol {
                 index: 1,
                 section_index: Some(1),
-                name: Some("my_config".to_string()),
+                name: Some("my_config".to_owned()),
                 address: 0,
                 size: 3,
                 is_definition: true,

aya-tool/src/generate.rs

@@ -157,7 +157,7 @@ mod test {
     fn test_extract_ctypes_prefix() {
         let (flags, prefix) = extract_ctypes_prefix(&to_vec("foo --ctypes-prefix bar baz"));
         assert_eq!(flags, to_vec("foo baz"));
-        assert_eq!(prefix, Some("bar".to_string()));
+        assert_eq!(prefix.as_deref(), Some("bar"));
 
         let (flags, prefix) = extract_ctypes_prefix(&to_vec("foo --ctypes-prefi bar baz"));
         assert_eq!(flags, to_vec("foo --ctypes-prefi bar baz"));
@@ -170,7 +170,7 @@ mod test {
         let (flags, prefix) = extract_ctypes_prefix(&to_vec("--ctypes-prefix foo"));
         let empty: Vec<String> = Vec::new();
         assert_eq!(flags, empty);
-        assert_eq!(prefix, Some("foo".to_string()));
+        assert_eq!(prefix.as_deref(), Some("foo"));
 
         let (flags, prefix) = extract_ctypes_prefix(&to_vec("--ctypes-prefix"));
         assert_eq!(flags, to_vec("--ctypes-prefix"));
@@ -181,32 +181,32 @@ mod test {
     fn test_combine_flags() {
         assert_eq!(
             combine_flags(&to_vec("a b"), &to_vec("c d"),).join(" "),
-            "a b c d".to_string(),
+            "a b c d",
         );
 
         assert_eq!(
             combine_flags(&to_vec("a -- b"), &to_vec("a b"),).join(" "),
-            "a a b -- b".to_string(),
+            "a a b -- b",
         );
 
         assert_eq!(
             combine_flags(&to_vec("a -- b"), &to_vec("c d"),).join(" "),
-            "a c d -- b".to_string(),
+            "a c d -- b",
         );
 
         assert_eq!(
             combine_flags(&to_vec("a b"), &to_vec("c -- d"),).join(" "),
-            "a b c -- d".to_string(),
+            "a b c -- d",
         );
 
         assert_eq!(
             combine_flags(&to_vec("a -- b"), &to_vec("c -- d"),).join(" "),
-            "a c -- b d".to_string(),
+            "a c -- b d",
         );
 
         assert_eq!(
             combine_flags(&to_vec("a -- b"), &to_vec("-- c d"),).join(" "),
-            "a -- b c d".to_string(),
+            "a -- b c d",
         );
     }
 }

aya/src/bpf.rs

@@ -425,13 +425,13 @@ impl<'a> BpfLoader<'a> {
             if !map.obj.data().is_empty() && map.obj.section_kind() != BpfSectionKind::Bss {
                 bpf_map_update_elem_ptr(fd, &0 as *const _, map.obj.data_mut().as_mut_ptr(), 0)
                     .map_err(|(_, io_error)| MapError::SyscallError {
-                        call: "bpf_map_update_elem".to_owned(),
+                        call: "bpf_map_update_elem",
                         io_error,
                     })?;
             }
             if map.obj.section_kind() == BpfSectionKind::Rodata {
                 bpf_map_freeze(fd).map_err(|(_, io_error)| MapError::SyscallError {
-                    call: "bpf_map_freeze".to_owned(),
+                    call: "bpf_map_freeze",
                     io_error,
                 })?;
             }

aya/src/maps/array/array.rs

@@ -67,7 +67,7 @@ impl<T: Borrow<MapData>, V: Pod> Array<T, V> {
 
         let value = bpf_map_lookup_elem(fd, index, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             }
         })?;
@@ -94,7 +94,7 @@ impl<T: BorrowMut<MapData>, V: Pod> Array<T, V> {
         let fd = data.fd_or_err()?;
         bpf_map_update_elem(fd, Some(&index), value.borrow(), flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             }
         })?;

aya/src/maps/array/per_cpu_array.rs

@@ -86,7 +86,7 @@ impl<T: Borrow<MapData>, V: Pod> PerCpuArray<T, V> {
 
         let value = bpf_map_lookup_elem_per_cpu(fd, index, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             }
         })?;
@@ -114,7 +114,7 @@ impl<T: BorrowMut<MapData>, V: Pod> PerCpuArray<T, V> {
 
         bpf_map_update_elem_per_cpu(fd, &index, &values, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             }
         })?;

aya/src/maps/array/program_array.rs

@@ -81,7 +81,7 @@ impl<T: BorrowMut<MapData>> ProgramArray<T> {
 
         bpf_map_update_elem(fd, Some(&index), &prog_fd, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             }
         })?;
@@ -100,7 +100,7 @@ impl<T: BorrowMut<MapData>> ProgramArray<T> {
         bpf_map_delete_elem(fd, index)
             .map(|_| ())
             .map_err(|(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_delete_elem".to_owned(),
+                call: "bpf_map_delete_elem",
                 io_error,
             })
     }

aya/src/maps/bloom_filter.rs

@@ -54,7 +54,7 @@ impl<T: Borrow<MapData>, V: Pod> BloomFilter<T, V> {
 
         bpf_map_lookup_elem_ptr::<u32, _>(fd, None, &mut value, flags)
             .map_err(|(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             })?
             .ok_or(MapError::ElementNotFound)?;
@@ -66,7 +66,7 @@ impl<T: Borrow<MapData>, V: Pod> BloomFilter<T, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         bpf_map_push_elem(fd, value.borrow(), flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_push_elem".to_owned(),
+                call: "bpf_map_push_elem",
                 io_error,
             }
         })?;

aya/src/maps/hash_map/hash_map.rs

@@ -56,7 +56,7 @@ impl<T: Borrow<MapData>, K: Pod, V: Pod> HashMap<T, K, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         let value = bpf_map_lookup_elem(fd, key, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             }
         })?;

aya/src/maps/hash_map/mod.rs

@@ -23,7 +23,7 @@ pub(crate) fn insert<K: Pod, V: Pod>(
     let fd = map.fd_or_err()?;
     bpf_map_update_elem(fd, Some(key), value, flags).map_err(|(_, io_error)| {
         MapError::SyscallError {
-            call: "bpf_map_update_elem".to_owned(),
+            call: "bpf_map_update_elem",
             io_error,
         }
     })?;
@@ -36,7 +36,7 @@ pub(crate) fn remove<K: Pod>(map: &mut MapData, key: &K) -> Result<(), MapError>
     bpf_map_delete_elem(fd, key)
         .map(|_| ())
         .map_err(|(_, io_error)| MapError::SyscallError {
-            call: "bpf_map_delete_elem".to_owned(),
+            call: "bpf_map_delete_elem",
             io_error,
         })
 }

aya/src/maps/hash_map/per_cpu_hash_map.rs

@@ -66,7 +66,7 @@ impl<T: Borrow<MapData>, K: Pod, V: Pod> PerCpuHashMap<T, K, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         let values = bpf_map_lookup_elem_per_cpu(fd, key, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             }
         })?;
@@ -124,7 +124,7 @@ impl<T: BorrowMut<MapData>, K: Pod, V: Pod> PerCpuHashMap<T, K, V> {
         let fd = self.inner.borrow_mut().fd_or_err()?;
         bpf_map_update_elem_per_cpu(fd, key.borrow(), &values, flags).map_err(
             |(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             },
         )?;

aya/src/maps/lpm_trie.rs

@@ -130,7 +130,7 @@ impl<T: Borrow<MapData>, K: Pod, V: Pod> LpmTrie<T, K, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         let value = bpf_map_lookup_elem(fd, key, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             }
         })?;
@@ -161,7 +161,7 @@ impl<T: BorrowMut<MapData>, K: Pod, V: Pod> LpmTrie<T, K, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         bpf_map_update_elem(fd, Some(key), value.borrow(), flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             }
         })?;
@@ -177,7 +177,7 @@ impl<T: BorrowMut<MapData>, K: Pod, V: Pod> LpmTrie<T, K, V> {
         bpf_map_delete_elem(fd, key)
             .map(|_| ())
             .map_err(|(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_delete_elem".to_owned(),
+                call: "bpf_map_delete_elem",
                 io_error,
             })
     }

aya/src/maps/mod.rs

@@ -168,7 +168,7 @@ pub enum MapError {
     #[error("the `{call}` syscall failed")]
     SyscallError {
         /// Syscall Name
-        call: String,
+        call: &'static str,
         /// Original io::Error
         io_error: io::Error,
     },
@@ -518,7 +518,7 @@ impl MapData {
         let map_path = path.as_ref().join(name);
         let path_string = CString::new(map_path.to_str().unwrap()).unwrap();
         let fd = bpf_get_object(&path_string).map_err(|(_, io_error)| MapError::SyscallError {
-            call: "BPF_OBJ_GET".to_string(),
+            call: "BPF_OBJ_GET",
             io_error,
         })? as RawFd;
 
@@ -540,12 +540,12 @@ impl MapData {
             })?;
 
         let fd = bpf_get_object(&path_string).map_err(|(_, io_error)| MapError::SyscallError {
-            call: "BPF_OBJ_GET".to_owned(),
+            call: "BPF_OBJ_GET",
             io_error,
         })? as RawFd;
 
         let info = bpf_map_get_info_by_fd(fd).map_err(|io_error| MapError::SyscallError {
-            call: "BPF_MAP_GET_INFO_BY_FD".to_owned(),
+            call: "BPF_MAP_GET_INFO_BY_FD",
             io_error,
         })?;
 
@@ -564,7 +564,7 @@ impl MapData {
     /// 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| MapError::SyscallError {
-            call: "BPF_OBJ_GET".to_owned(),
+            call: "BPF_OBJ_GET",
             io_error,
         })?;
 
@@ -594,7 +594,7 @@ impl MapData {
             }
         })?;
         bpf_pin_object(fd, &path_string).map_err(|(_, io_error)| PinError::SyscallError {
-            name: "BPF_OBJ_PIN".to_string(),
+            name: "BPF_OBJ_PIN",
             io_error,
         })?;
         self.pinned = true;
@@ -683,7 +683,7 @@ impl<K: Pod> Iterator for MapKeys<'_, K> {
             Err((_, io_error)) => {
                 self.err = true;
                 Some(Err(MapError::SyscallError {
-                    call: "bpf_map_get_next_key".to_owned(),
+                    call: "bpf_map_get_next_key",
                     io_error,
                 }))
             }

aya/src/maps/queue.rs

@@ -66,7 +66,7 @@ impl<T: BorrowMut<MapData>, V: Pod> Queue<T, V> {
 
         let value = bpf_map_lookup_and_delete_elem::<u32, _>(fd, None, flags).map_err(
             |(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_lookup_and_delete_elem".to_owned(),
+                call: "bpf_map_lookup_and_delete_elem",
                 io_error,
             },
         )?;
@@ -82,7 +82,7 @@ impl<T: BorrowMut<MapData>, V: Pod> Queue<T, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         bpf_map_push_elem(fd, value.borrow(), flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_push_elem".to_owned(),
+                call: "bpf_map_push_elem",
                 io_error,
             }
         })?;

aya/src/maps/sock/sock_hash.rs

@@ -85,7 +85,7 @@ impl<T: Borrow<MapData>, K: Pod> SockHash<T, K> {
         let fd = self.inner.borrow().fd_or_err()?;
         let value = bpf_map_lookup_elem(fd, key, flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             }
         })?;

aya/src/maps/sock/sock_map.rs

@@ -77,7 +77,7 @@ impl<T: BorrowMut<MapData>> SockMap<T> {
         check_bounds(data, index)?;
         bpf_map_update_elem(fd, Some(&index), &socket.as_raw_fd(), flags).map_err(
             |(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             },
         )?;
@@ -92,7 +92,7 @@ impl<T: BorrowMut<MapData>> SockMap<T> {
         bpf_map_delete_elem(fd, index)
             .map(|_| ())
             .map_err(|(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_delete_elem".to_owned(),
+                call: "bpf_map_delete_elem",
                 io_error,
             })
     }

aya/src/maps/stack.rs

@@ -66,7 +66,7 @@ impl<T: BorrowMut<MapData>, V: Pod> Stack<T, V> {
 
         let value = bpf_map_lookup_and_delete_elem::<u32, _>(fd, None, flags).map_err(
             |(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_lookup_and_delete_elem".to_owned(),
+                call: "bpf_map_lookup_and_delete_elem",
                 io_error,
             },
         )?;
@@ -82,7 +82,7 @@ impl<T: BorrowMut<MapData>, V: Pod> Stack<T, V> {
         let fd = self.inner.borrow().fd_or_err()?;
         bpf_map_update_elem(fd, None::<&u32>, value.borrow(), flags).map_err(|(_, io_error)| {
             MapError::SyscallError {
-                call: "bpf_map_update_elem".to_owned(),
+                call: "bpf_map_update_elem",
                 io_error,
             }
         })?;

aya/src/maps/stack_trace.rs

@@ -52,8 +52,8 @@ use crate::{
 ///         frame.ip,
 ///         frame
 ///             .symbol_name
-///             .as_ref()
-///             .unwrap_or(&"[unknown symbol name]".to_owned())
+///             .as_deref()
+///             .unwrap_or("[unknown symbol name]")
 ///     );
 /// }
 ///
@@ -79,7 +79,7 @@ impl<T: Borrow<MapData>> StackTraceMap<T> {
         let max_stack_depth =
             sysctl::<usize>("kernel/perf_event_max_stack").map_err(|io_error| {
                 MapError::SyscallError {
-                    call: "sysctl".to_owned(),
+                    call: "sysctl",
                     io_error,
                 }
             })?;
@@ -107,7 +107,7 @@ impl<T: Borrow<MapData>> StackTraceMap<T> {
         let mut frames = vec![0; self.max_stack_depth];
         bpf_map_lookup_elem_ptr(fd, Some(stack_id), frames.as_mut_ptr(), flags)
             .map_err(|(_, io_error)| MapError::SyscallError {
-                call: "bpf_map_lookup_elem".to_owned(),
+                call: "bpf_map_lookup_elem",
                 io_error,
             })?
             .ok_or(MapError::KeyNotFound)?;

aya/src/pin.rs

@@ -27,7 +27,7 @@ pub enum PinError {
     #[error("{name} failed")]
     SyscallError {
         /// The syscall name.
-        name: String,
+        name: &'static str,
         /// The [`io::Error`] returned by the syscall.
         #[source]
         io_error: io::Error,

aya/src/programs/cgroup_device.rs

@@ -66,7 +66,7 @@ impl CgroupDevice {
         if k_ver >= (5, 7, 0) {
             let link_fd = bpf_link_create(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, None, 0).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -78,7 +78,7 @@ impl CgroupDevice {
         } else {
             bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_prog_attach".to_owned(),
+                    call: "bpf_prog_attach",
                     io_error,
                 }
             })?;

aya/src/programs/cgroup_skb.rs

@@ -100,7 +100,7 @@ impl CgroupSkb {
         if k_ver >= (5, 7, 0) {
             let link_fd = bpf_link_create(prog_fd, cgroup_fd, attach_type, None, 0).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -112,7 +112,7 @@ impl CgroupSkb {
         } else {
             bpf_prog_attach(prog_fd, cgroup_fd, attach_type).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_prog_attach".to_owned(),
+                    call: "bpf_prog_attach",
                     io_error,
                 }
             })?;

aya/src/programs/cgroup_sock.rs

@@ -75,7 +75,7 @@ impl CgroupSock {
         if k_ver >= (5, 7, 0) {
             let link_fd = bpf_link_create(prog_fd, cgroup_fd, attach_type, None, 0).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -87,7 +87,7 @@ impl CgroupSock {
         } else {
             bpf_prog_attach(prog_fd, cgroup_fd, attach_type).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_prog_attach".to_owned(),
+                    call: "bpf_prog_attach",
                     io_error,
                 }
             })?;

aya/src/programs/cgroup_sock_addr.rs

@@ -76,7 +76,7 @@ impl CgroupSockAddr {
         if k_ver >= (5, 7, 0) {
             let link_fd = bpf_link_create(prog_fd, cgroup_fd, attach_type, None, 0).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -88,7 +88,7 @@ impl CgroupSockAddr {
         } else {
             bpf_prog_attach(prog_fd, cgroup_fd, attach_type).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_prog_attach".to_owned(),
+                    call: "bpf_prog_attach",
                     io_error,
                 }
             })?;

aya/src/programs/cgroup_sockopt.rs

@@ -73,7 +73,7 @@ impl CgroupSockopt {
         if k_ver >= (5, 7, 0) {
             let link_fd = bpf_link_create(prog_fd, cgroup_fd, attach_type, None, 0).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -85,7 +85,7 @@ impl CgroupSockopt {
         } else {
             bpf_prog_attach(prog_fd, cgroup_fd, attach_type).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_prog_attach".to_owned(),
+                    call: "bpf_prog_attach",
                     io_error,
                 }
             })?;

aya/src/programs/cgroup_sysctl.rs

@@ -68,7 +68,7 @@ impl CgroupSysctl {
         if k_ver >= (5, 7, 0) {
             let link_fd = bpf_link_create(prog_fd, cgroup_fd, BPF_CGROUP_SYSCTL, None, 0).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -80,7 +80,7 @@ impl CgroupSysctl {
         } else {
             bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SYSCTL).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_prog_attach".to_owned(),
+                    call: "bpf_prog_attach",
                     io_error,
                 }
             })?;

aya/src/programs/extension.rs

@@ -92,7 +92,7 @@ impl Extension {
         // the attach type must be set as 0, which is bpf_attach_type::BPF_CGROUP_INET_INGRESS
         let link_fd = bpf_link_create(prog_fd, target_fd, BPF_CGROUP_INET_INGRESS, Some(btf_id), 0)
             .map_err(|(_, io_error)| ProgramError::SyscallError {
-                call: "bpf_link_create".to_owned(),
+                call: "bpf_link_create",
                 io_error,
             })? as RawFd;
         self.data
@@ -122,7 +122,7 @@ impl Extension {
         // the attach type must be set as 0, which is bpf_attach_type::BPF_CGROUP_INET_INGRESS
         let link_fd = bpf_link_create(prog_fd, target_fd, BPF_CGROUP_INET_INGRESS, Some(btf_id), 0)
             .map_err(|(_, io_error)| ProgramError::SyscallError {
-                call: "bpf_link_create".to_owned(),
+                call: "bpf_link_create",
                 io_error,
             })? as RawFd;
         self.data
@@ -153,7 +153,7 @@ fn get_btf_info(prog_fd: i32, func_name: &str) -> Result<(RawFd, u32), ProgramEr
     // retrieve program information
     let info =
         sys::bpf_prog_get_info_by_fd(prog_fd).map_err(|io_error| ProgramError::SyscallError {
-            call: "bpf_prog_get_info_by_fd".to_owned(),
+            call: "bpf_prog_get_info_by_fd",
             io_error,
         })?;
 
@@ -165,7 +165,7 @@ fn get_btf_info(prog_fd: i32, func_name: &str) -> Result<(RawFd, u32), ProgramEr
     // the bpf fd of the BTF object
     let btf_fd =
         sys::bpf_btf_get_fd_by_id(info.btf_id).map_err(|io_error| ProgramError::SyscallError {
-            call: "bpf_btf_get_fd_by_id".to_owned(),
+            call: "bpf_btf_get_fd_by_id",
             io_error,
         })?;
 
@@ -179,7 +179,7 @@ fn get_btf_info(prog_fd: i32, func_name: &str) -> Result<(RawFd, u32), ProgramEr
                 let btf_info =
                     sys::btf_obj_get_info_by_fd(btf_fd, &mut buf).map_err(|io_error| {
                         ProgramError::SyscallError {
-                            call: "bpf_prog_get_info_by_fd".to_owned(),
+                            call: "bpf_prog_get_info_by_fd",
                             io_error,
                         }
                     })?;
@@ -189,7 +189,7 @@ fn get_btf_info(prog_fd: i32, func_name: &str) -> Result<(RawFd, u32), ProgramEr
             }
         }
         Err(io_error) => Err(ProgramError::SyscallError {
-            call: "bpf_prog_get_info_by_fd".to_owned(),
+            call: "bpf_prog_get_info_by_fd",
             io_error,
         }),
     }?;

aya/src/programs/links.rs

@@ -129,7 +129,7 @@ impl FdLink {
                 }
             })?;
         bpf_pin_object(self.fd, &path_string).map_err(|(_, io_error)| PinError::SyscallError {
-            name: "BPF_OBJ_PIN".to_string(),
+            name: "BPF_OBJ_PIN",
             io_error,
         })?;
         Ok(PinnedLink::new(PathBuf::from(path.as_ref()), self))
@@ -186,7 +186,7 @@ impl PinnedLink {
         let path_string = CString::new(path.as_ref().to_string_lossy().to_string()).unwrap();
         let fd =
             bpf_get_object(&path_string).map_err(|(code, io_error)| LinkError::SyscallError {
-                call: "BPF_OBJ_GET".to_string(),
+                call: "BPF_OBJ_GET",
                 code,
                 io_error,
             })? as RawFd;
@@ -318,7 +318,7 @@ pub enum LinkError {
     #[error("the `{call}` syscall failed with code {code}")]
     SyscallError {
         /// Syscall Name.
-        call: String,
+        call: &'static str,
         /// Error code.
         code: libc::c_long,
         #[source]

aya/src/programs/lirc_mode2.rs

@@ -66,7 +66,7 @@ impl LircMode2 {
 
         bpf_prog_attach(prog_fd, lircdev_fd, BPF_LIRC_MODE2).map_err(|(_, io_error)| {
             ProgramError::SyscallError {
-                call: "bpf_prog_attach".to_owned(),
+                call: "bpf_prog_attach",
                 io_error,
             }
         })?;
@@ -97,7 +97,7 @@ impl LircMode2 {
 
         for id in prog_ids {
             let fd = bpf_prog_get_fd_by_id(id).map_err(|io_error| ProgramError::SyscallError {
-                call: "bpf_prog_get_fd_by_id".to_owned(),
+                call: "bpf_prog_get_fd_by_id",
                 io_error,
             })?;
 
@@ -135,7 +135,7 @@ impl LircLink {
         match bpf_prog_get_info_by_fd(self.prog_fd) {
             Ok(info) => Ok(ProgramInfo(info)),
             Err(io_error) => Err(ProgramError::SyscallError {
-                call: "bpf_prog_get_info_by_fd".to_owned(),
+                call: "bpf_prog_get_info_by_fd",
                 io_error,
             }),
         }

aya/src/programs/mod.rs

@@ -148,7 +148,7 @@ pub enum ProgramError {
     #[error("`{call}` failed")]
     SyscallError {
         /// The name of the syscall which failed.
-        call: String,
+        call: &'static str,
         /// The [`io::Error`] returned by the syscall.
         #[source]
         io_error: io::Error,
@@ -455,7 +455,7 @@ impl<T: Link> ProgramData<T> {
         let attach_btf_obj_fd = if info.attach_btf_obj_id > 0 {
             let fd = bpf_btf_get_fd_by_id(info.attach_btf_obj_id).map_err(|io_error| {
                 ProgramError::SyscallError {
-                    call: "bpf_btf_get_fd_by_id".to_string(),
+                    call: "bpf_btf_get_fd_by_id",
                     io_error,
                 }
             })?;
@@ -487,12 +487,12 @@ impl<T: Link> ProgramData<T> {
             CString::new(path.as_ref().as_os_str().to_string_lossy().as_bytes()).unwrap();
         let fd =
             bpf_get_object(&path_string).map_err(|(_, io_error)| ProgramError::SyscallError {
-                call: "bpf_obj_get".to_owned(),
+                call: "bpf_obj_get",
                 io_error,
             })? as RawFd;
 
         let info = bpf_prog_get_info_by_fd(fd).map_err(|io_error| ProgramError::SyscallError {
-            call: "bpf_prog_get_info_by_fd".to_owned(),
+            call: "bpf_prog_get_info_by_fd",
             io_error,
         })?;
 
@@ -528,8 +528,8 @@ fn pin_program<T: Link, P: AsRef<Path>>(
     let fd = data.fd.ok_or(PinError::NoFd {
         name: data
             .name
-            .as_ref()
-            .unwrap_or(&"<unknown program>".to_string())
+            .as_deref()
+            .unwrap_or("<unknown program>")
             .to_string(),
     })?;
     let path_string = CString::new(path.as_ref().to_string_lossy().into_owned()).map_err(|e| {
@@ -538,7 +538,7 @@ fn pin_program<T: Link, P: AsRef<Path>>(
         }
     })?;
     bpf_pin_object(fd, &path_string).map_err(|(_, io_error)| PinError::SyscallError {
-        name: "BPF_OBJ_PIN".to_string(),
+        name: "BPF_OBJ_PIN",
         io_error,
     })?;
     Ok(())
@@ -666,7 +666,7 @@ pub(crate) fn query<T: AsRawFd>(
             }
             Err((_, io_error)) => {
                 return Err(ProgramError::SyscallError {
-                    call: "bpf_prog_query".to_owned(),
+                    call: "bpf_prog_query",
                     io_error,
                 });
             }
@@ -948,7 +948,7 @@ impl ProgramInfo {
     pub fn fd(&self) -> Result<RawFd, ProgramError> {
         let fd =
             bpf_prog_get_fd_by_id(self.0.id).map_err(|io_error| ProgramError::SyscallError {
-                call: "bpf_prog_get_fd_by_id".to_owned(),
+                call: "bpf_prog_get_fd_by_id",
                 io_error,
             })?;
         Ok(fd as RawFd)
@@ -959,12 +959,12 @@ impl ProgramInfo {
         let path_string = CString::new(path.as_ref().to_str().unwrap()).unwrap();
         let fd =
             bpf_get_object(&path_string).map_err(|(_, io_error)| ProgramError::SyscallError {
-                call: "BPF_OBJ_GET".to_owned(),
+                call: "BPF_OBJ_GET",
                 io_error,
             })? as RawFd;
 
         let info = bpf_prog_get_info_by_fd(fd).map_err(|io_error| ProgramError::SyscallError {
-            call: "bpf_prog_get_info_by_fd".to_owned(),
+            call: "bpf_prog_get_info_by_fd",
             io_error,
         })?;
         unsafe {
@@ -995,13 +995,13 @@ impl Iterator for ProgramsIter {
                 Some(
                     bpf_prog_get_fd_by_id(next)
                         .map_err(|io_error| ProgramError::SyscallError {
-                            call: "bpf_prog_get_fd_by_id".to_owned(),
+                            call: "bpf_prog_get_fd_by_id",
                             io_error,
                         })
                         .and_then(|fd| {
                             let info = bpf_prog_get_info_by_fd(fd)
                                 .map_err(|io_error| ProgramError::SyscallError {
-                                    call: "bpf_prog_get_info_by_fd".to_owned(),
+                                    call: "bpf_prog_get_info_by_fd",
                                     io_error,
                                 })
                                 .map(ProgramInfo);
@@ -1016,7 +1016,7 @@ impl Iterator for ProgramsIter {
                 // iteration to avoid an infinite loop.
                 self.error = true;
                 Some(Err(ProgramError::SyscallError {
-                    call: "bpf_prog_get_fd_by_id".to_owned(),
+                    call: "bpf_prog_get_fd_by_id",
                     io_error,
                 }))
             }

aya/src/programs/perf_attach.rs

@@ -77,7 +77,7 @@ pub(crate) fn perf_attach(prog_fd: RawFd, fd: RawFd) -> Result<PerfLinkInner, Pr
         let link_fd =
             bpf_link_create(prog_fd, fd, BPF_PERF_EVENT, None, 0).map_err(|(_, io_error)| {
                 ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 }
             })? as RawFd;
@@ -104,13 +104,13 @@ fn perf_attach_either(
 ) -> Result<PerfLinkInner, ProgramError> {
     perf_event_ioctl(fd, PERF_EVENT_IOC_SET_BPF, prog_fd).map_err(|(_, io_error)| {
         ProgramError::SyscallError {
-            call: "PERF_EVENT_IOC_SET_BPF".to_owned(),
+            call: "PERF_EVENT_IOC_SET_BPF",
             io_error,
         }
     })?;
     perf_event_ioctl(fd, PERF_EVENT_IOC_ENABLE, 0).map_err(|(_, io_error)| {
         ProgramError::SyscallError {
-            call: "PERF_EVENT_IOC_ENABLE".to_owned(),
+            call: "PERF_EVENT_IOC_ENABLE",
             io_error,
         }
     })?;

aya/src/programs/perf_event.rs

@@ -165,7 +165,7 @@ impl PerfEvent {
             0,
         )
         .map_err(|(_code, io_error)| ProgramError::SyscallError {
-            call: "perf_event_open".to_owned(),
+            call: "perf_event_open",
             io_error,
         })? as i32;
 

aya/src/programs/probe.rs

@@ -110,7 +110,7 @@ fn create_as_probe(
 
     let fd = perf_event_open_probe(perf_ty, ret_bit, fn_name, offset, pid).map_err(
         |(_code, io_error)| ProgramError::SyscallError {
-            call: "perf_event_open".to_owned(),
+            call: "perf_event_open",
             io_error,
         },
     )? as i32;
@@ -139,7 +139,7 @@ fn create_as_trace_point(
     let tpid = read_sys_fs_trace_point_id(tracefs, &category, &event_alias)?;
     let fd = perf_event_open_trace_point(tpid, pid).map_err(|(_code, io_error)| {
         ProgramError::SyscallError {
-            call: "perf_event_open".to_owned(),
+            call: "perf_event_open",
             io_error,
         }
     })? as i32;
@@ -174,7 +174,7 @@ fn create_probe_event(
     let offset_suffix = match kind {
         KProbe => format!("+{offset}"),
         UProbe | URetProbe => format!(":{offset:#x}"),
-        _ => "".to_string(),
+        _ => String::new(),
     };
     let probe = format!(
         "{}:{}s/{} {}{}\n",

aya/src/programs/sk_lookup.rs

@@ -66,7 +66,7 @@ impl SkLookup {
 
         let link_fd = bpf_link_create(prog_fd, netns_fd, BPF_SK_LOOKUP, None, 0).map_err(
             |(_, io_error)| ProgramError::SyscallError {
-                call: "bpf_link_create".to_owned(),
+                call: "bpf_link_create",
                 io_error,
             },
         )? as RawFd;

aya/src/programs/sk_msg.rs

@@ -84,7 +84,7 @@ impl SkMsg {
 
         bpf_prog_attach(prog_fd, map_fd, BPF_SK_MSG_VERDICT).map_err(|(_, io_error)| {
             ProgramError::SyscallError {
-                call: "bpf_prog_attach".to_owned(),
+                call: "bpf_prog_attach",
                 io_error,
             }
         })?;

aya/src/programs/sk_skb.rs

@@ -80,7 +80,7 @@ impl SkSkb {
         };
         bpf_prog_attach(prog_fd, map_fd, attach_type).map_err(|(_, io_error)| {
             ProgramError::SyscallError {
-                call: "bpf_prog_attach".to_owned(),
+                call: "bpf_prog_attach",
                 io_error,
             }
         })?;

aya/src/programs/sock_ops.rs

@@ -64,7 +64,7 @@ impl SockOps {
 
         bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS).map_err(|(_, io_error)| {
             ProgramError::SyscallError {
-                call: "bpf_prog_attach".to_owned(),
+                call: "bpf_prog_attach",
                 io_error,
             }
         })?;

aya/src/programs/tc.rs

@@ -265,13 +265,13 @@ impl SchedClassifierLink {
     /// #     #[error(transparent)]
     /// #     IO(#[from] std::io::Error),
     /// # }
-    /// # fn read_persisted_link_details() -> (String, TcAttachType, u16, u32) {
-    /// #     ("eth0".to_string(), TcAttachType::Ingress, 50, 1)
+    /// # fn read_persisted_link_details() -> (&'static str, TcAttachType, u16, u32) {
+    /// #     ("eth0", TcAttachType::Ingress, 50, 1)
     /// # }
     /// // Get the link parameters from some external source. Where and how the parameters are
     /// // persisted is up to your application.
     /// let (if_name, attach_type, priority, handle) = read_persisted_link_details();
-    /// let new_tc_link = SchedClassifierLink::attached(&if_name, attach_type, priority, handle)?;
+    /// let new_tc_link = SchedClassifierLink::attached(if_name, attach_type, priority, handle)?;
     ///
     /// # Ok::<(), Error>(())
     /// ```

aya/src/programs/trace_point.rs

@@ -82,7 +82,7 @@ impl TracePoint {
         let id = read_sys_fs_trace_point_id(tracefs, category, name)?;
         let fd = perf_event_open_trace_point(id, None).map_err(|(_code, io_error)| {
             ProgramError::SyscallError {
-                call: "perf_event_open".to_owned(),
+                call: "perf_event_open",
                 io_error,
             }
         })? as i32;

aya/src/programs/utils.rs

@@ -15,7 +15,7 @@ pub(crate) fn attach_raw_tracepoint<T: Link + From<FdLink>>(
 
     let pfd = bpf_raw_tracepoint_open(tp_name, prog_fd).map_err(|(_code, io_error)| {
         ProgramError::SyscallError {
-            call: "bpf_raw_tracepoint_open".to_owned(),
+            call: "bpf_raw_tracepoint_open",
             io_error,
         }
     })? as RawFd;

aya/src/programs/xdp.rs

@@ -130,7 +130,7 @@ impl Xdp {
         if k_ver >= (5, 9, 0) {
             let link_fd = bpf_link_create(prog_fd, if_index, BPF_XDP, None, flags.bits()).map_err(
                 |(_, io_error)| ProgramError::SyscallError {
-                    call: "bpf_link_create".to_owned(),
+                    call: "bpf_link_create",
                     io_error,
                 },
             )? as RawFd;
@@ -176,7 +176,7 @@ impl Xdp {
                 let link_fd = fd_link.fd;
                 bpf_link_update(link_fd, prog_fd, None, 0).map_err(|(_, io_error)| {
                     ProgramError::SyscallError {
-                        call: "bpf_link_update".to_string(),
+                        call: "bpf_link_update",
                         io_error,
                     }
                 })?;
@@ -284,7 +284,7 @@ impl TryFrom<FdLink> for XdpLink {
         // 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| LinkError::SyscallError {
-                call: "BPF_OBJ_GET_INFO_BY_FD".to_string(),
+                call: "BPF_OBJ_GET_INFO_BY_FD",
                 code: 0,
                 io_error,
             })?;

aya/src/sys/bpf.rs

@@ -748,7 +748,7 @@ pub(crate) fn is_bpf_cookie_supported() -> bool {
 
 pub(crate) fn is_btf_supported() -> bool {
     let mut btf = Btf::new();
-    let name_offset = btf.add_string("int".to_string());
+    let name_offset = btf.add_string("int");
     let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
     btf.add_type(int_type);
     let btf_bytes = btf.to_bytes();
@@ -770,12 +770,12 @@ pub(crate) fn is_btf_supported() -> bool {
 
 pub(crate) fn is_btf_func_supported() -> bool {
     let mut btf = Btf::new();
-    let name_offset = btf.add_string("int".to_string());
+    let name_offset = btf.add_string("int");
     let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
     let int_type_id = btf.add_type(int_type);
 
-    let a_name = btf.add_string("a".to_string());
-    let b_name = btf.add_string("b".to_string());
+    let a_name = btf.add_string("a");
+    let b_name = btf.add_string("b");
     let params = vec![
         BtfParam {
             name_offset: a_name,
@@ -789,7 +789,7 @@ pub(crate) fn is_btf_func_supported() -> bool {
     let func_proto = BtfType::FuncProto(FuncProto::new(params, int_type_id));
     let func_proto_type_id = btf.add_type(func_proto);
 
-    let add = btf.add_string("inc".to_string());
+    let add = btf.add_string("inc");
     let func = BtfType::Func(Func::new(add, func_proto_type_id, FuncLinkage::Static));
     btf.add_type(func);
 
@@ -812,12 +812,12 @@ pub(crate) fn is_btf_func_supported() -> bool {
 
 pub(crate) fn is_btf_func_global_supported() -> bool {
     let mut btf = Btf::new();
-    let name_offset = btf.add_string("int".to_string());
+    let name_offset = btf.add_string("int");
     let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
     let int_type_id = btf.add_type(int_type);
 
-    let a_name = btf.add_string("a".to_string());
-    let b_name = btf.add_string("b".to_string());
+    let a_name = btf.add_string("a");
+    let b_name = btf.add_string("b");
     let params = vec![
         BtfParam {
             name_offset: a_name,
@@ -831,7 +831,7 @@ pub(crate) fn is_btf_func_global_supported() -> bool {
     let func_proto = BtfType::FuncProto(FuncProto::new(params, int_type_id));
     let func_proto_type_id = btf.add_type(func_proto);
 
-    let add = btf.add_string("inc".to_string());
+    let add = btf.add_string("inc");
     let func = BtfType::Func(Func::new(add, func_proto_type_id, FuncLinkage::Global));
     btf.add_type(func);
 
@@ -854,15 +854,15 @@ pub(crate) fn is_btf_func_global_supported() -> bool {
 
 pub(crate) fn is_btf_datasec_supported() -> bool {
     let mut btf = Btf::new();
-    let name_offset = btf.add_string("int".to_string());
+    let name_offset = btf.add_string("int");
     let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
     let int_type_id = btf.add_type(int_type);
 
-    let name_offset = btf.add_string("foo".to_string());
+    let name_offset = btf.add_string("foo");
     let var_type = BtfType::Var(Var::new(name_offset, int_type_id, VarLinkage::Static));
     let var_type_id = btf.add_type(var_type);
 
-    let name_offset = btf.add_string(".data".to_string());
+    let name_offset = btf.add_string(".data");
     let variables = vec![DataSecEntry {
         btf_type: var_type_id,
         offset: 0,
@@ -890,7 +890,7 @@ pub(crate) fn is_btf_datasec_supported() -> bool {
 
 pub(crate) fn is_btf_float_supported() -> bool {
     let mut btf = Btf::new();
-    let name_offset = btf.add_string("float".to_string());
+    let name_offset = btf.add_string("float");
     let float_type = BtfType::Float(Float::new(name_offset, 16));
     btf.add_type(float_type);
 
@@ -913,15 +913,15 @@ pub(crate) fn is_btf_float_supported() -> bool {
 
 pub(crate) fn is_btf_decl_tag_supported() -> bool {
     let mut btf = Btf::new();
-    let name_offset = btf.add_string("int".to_string());
+    let name_offset = btf.add_string("int");
     let int_type = BtfType::Int(Int::new(name_offset, 4, IntEncoding::Signed, 0));
     let int_type_id = btf.add_type(int_type);
 
-    let name_offset = btf.add_string("foo".to_string());
+    let name_offset = btf.add_string("foo");
     let var_type = BtfType::Var(Var::new(name_offset, int_type_id, VarLinkage::Static));
     let var_type_id = btf.add_type(var_type);
 
-    let name_offset = btf.add_string("decl_tag".to_string());
+    let name_offset = btf.add_string("decl_tag");
     let decl_tag = BtfType::DeclTag(DeclTag::new(name_offset, var_type_id, -1));
     btf.add_type(decl_tag);
 
@@ -948,7 +948,7 @@ pub(crate) fn is_btf_type_tag_supported() -> bool {
     let int_type = BtfType::Int(Int::new(0, 4, IntEncoding::Signed, 0));
     let int_type_id = btf.add_type(int_type);
 
-    let name_offset = btf.add_string("int".to_string());
+    let name_offset = btf.add_string("int");
     let type_tag = BtfType::TypeTag(TypeTag::new(name_offset, int_type_id));
     let type_tag_type = btf.add_type(type_tag);
 

xtask/src/build_ebpf.rs

@@ -19,13 +19,13 @@ pub enum Architecture {
 }
 
 impl std::str::FromStr for Architecture {
-    type Err = String;
+    type Err = &'static str;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         Ok(match s {
             "bpfel-unknown-none" => Architecture::BpfEl,
             "bpfeb-unknown-none" => Architecture::BpfEb,
-            _ => return Err("invalid target".to_owned()),
+            _ => return Err("invalid target"),
         })
     }
 }

xtask/src/codegen/mod.rs

@@ -28,7 +28,7 @@ impl Architecture {
 }
 
 impl std::str::FromStr for Architecture {
-    type Err = String;
+    type Err = &'static str;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         Ok(match s {
@@ -36,7 +36,7 @@ impl std::str::FromStr for Architecture {
             "armv7" => Architecture::ARMv7,
             "aarch64" => Architecture::AArch64,
             "riscv64" => Architecture::RISCV64,
-            _ => return Err("invalid architecture".to_owned()),
+            _ => return Err("invalid architecture"),
         })
     }
 }