Add lib module with conditional imports depending on std/no_std.

Signed-off-by: SzymonKubica <[email protected]> Add correct imports for cranelift feature. Signed-off-by: SzymonKubica <[email protected]> Add optional loading of dependencies available only when under std. Signed-off-by: SzymonKubica <[email protected]>
qmonnet · May 30, 2024 · 1544093 · 1544093
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diff --git a/Cargo.toml b/Cargo.toml
@@ -24,27 +24,30 @@ include = [
 
 [dependencies]
 
-combine = "4.6"
-libc = "0.2"
-time = "0.2"
-byteorder = "1.2"
+byteorder = { version = "1.2", default-features = false }
+log = {version = "0.4.21", default-features = false }
+
+# The following dependencies are only used when `std` is enabled.
+combine = { version = "4.6", optional = true }
+libc = { version = "0.2", optional = true }
+time = {version = "0.2", optional = true }
 
 # Optional Dependencies for the CraneLift JIT
-cranelift-codegen = { version = "0.99", optional = true }
-cranelift-frontend = { version = "0.99", optional = true }
-cranelift-jit = { version = "0.99", optional = true }
-cranelift-native = { version = "0.99", optional = true }
-cranelift-module = { version = "0.99", optional = true }
+cranelift-codegen = { version = "0.99",  optional = true }
+cranelift-frontend = { version = "0.99",  optional = true }
+cranelift-jit = { version = "0.99",  optional = true }
+cranelift-native = { version = "0.99",  optional = true }
+cranelift-module = { version = "0.99",  optional = true }
 
 [dev-dependencies]
 
-elf = "0.0.10"
-json = "0.11"
-hex = "0.4.3"
+elf = { version = "0.0.10", default-features = false }
+json = { version = "0.11", default-features = false }
+hex = { version = "0.4.3" }
 
 [features]
 default = ["std"]
-std = []
+std = ["dep:time", "dep:libc", "dep:combine"]
 cranelift = [
     "dep:cranelift-codegen",
     "dep:cranelift-frontend",

diff --git a/README.md b/README.md
@@ -447,9 +447,12 @@ fn main() {
     let mut vm = rbpf::EbpfVmFixedMbuff::new(Some(prog), 0x40, 0x50).unwrap();
 
     // We register a helper function, that can be called by the program, into
-    // the VM.
-    vm.register_helper(helpers::BPF_TRACE_PRINTK_IDX,
-                       helpers::bpf_trace_printf).unwrap();
+    // the VM. The `bpf_trace_printf` is only available when we have access to
+    // the standard library.
+    #[cfg(feature = "std")] {
+        vm.register_helper(helpers::BPF_TRACE_PRINTK_IDX,
+                           helpers::bpf_trace_printf).unwrap();
+    }
 
     // This kind of VM takes a reference to the packet data, but does not need
     // any reference to the metadata buffer: a fixed buffer is handled
@@ -469,17 +472,21 @@ methods are available.
 The first method consists in using the assembler provided by the crate.
 
 ```rust
-extern crate rbpf;
-use rbpf::assembler::assemble;
 
-let prog = assemble("add64 r1, 0x605
-                     mov64 r2, 0x32
-                     mov64 r1, r0
-                     be16 r0
-                     neg64 r2
-                     exit").unwrap();
-
-println!("{:?}", prog);
+extern crate rbpf;
+// These tests should only be run on std as they depend on the assembler.
+#[cfg(feature = "std")] {
+    use rbpf::assembler::assemble;
+
+    let prog = assemble("add64 r1, 0x605
+                         mov64 r2, 0x32
+                         mov64 r1, r0
+                         be16 r0
+                         neg64 r2
+                         exit").unwrap();
+
+    println!("{:?}", prog);
+}
 ```
 
 The above snippet will produce:
@@ -497,19 +504,21 @@ Conversely, a disassembler is also available to dump instruction names from
 bytecode in a human-friendly format.
 
 ```rust
-extern crate rbpf;
-use rbpf::disassembler::disassemble;
+#[cfg(feature = "std")] {
+    extern crate rbpf;
+    use rbpf::disassembler::disassemble;
 
-let prog = &[
-    0x07, 0x01, 0x00, 0x00, 0x05, 0x06, 0x00, 0x00,
-    0xb7, 0x02, 0x00, 0x00, 0x32, 0x00, 0x00, 0x00,
-    0xbf, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-    0xdc, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00,
-    0x87, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-    0x95, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
-];
+    let prog = &[
+        0x07, 0x01, 0x00, 0x00, 0x05, 0x06, 0x00, 0x00,
+        0xb7, 0x02, 0x00, 0x00, 0x32, 0x00, 0x00, 0x00,
+        0xbf, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0xdc, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00,
+        0x87, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x95, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+    ];
 
-disassemble(prog);
+    disassemble(prog);
+}
 ```
 
 This will produce the following output:

diff --git a/examples/disassemble.rs b/examples/disassemble.rs
@@ -1,37 +1,40 @@
 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
 // Copyright 2017 6WIND S.A. <[email protected]>
 
+
 extern crate rbpf;
 use rbpf::disassembler;
 
 // Simply disassemble a program into human-readable instructions.
 fn main() {
-    let prog = &[
-        0xb7, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x79, 0x12, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x79, 0x11, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0xbf, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x07, 0x03, 0x00, 0x00, 0x36, 0x00, 0x00, 0x00,
-        0x2d, 0x23, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x69, 0x12, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x55, 0x02, 0x10, 0x00, 0x08, 0x00, 0x00, 0x00,
-        0x71, 0x12, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x55, 0x02, 0x0e, 0x00, 0x06, 0x00, 0x00, 0x00,
-        0x18, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x79, 0x11, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0xbf, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x57, 0x02, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00,
-        0x15, 0x02, 0x08, 0x00, 0x99, 0x99, 0x00, 0x00,
-        0x18, 0x02, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x5f, 0x21, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0xb7, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-        0x18, 0x02, 0x00, 0x00, 0x00, 0x00, 0x99, 0x99,
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x1d, 0x21, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0xb7, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x95, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
-    ];
-    disassembler::disassemble(prog);
+    #[cfg(feature = "std")] {
+        let prog = &[
+            0xb7, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x79, 0x12, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x79, 0x11, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0xbf, 0x13, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x07, 0x03, 0x00, 0x00, 0x36, 0x00, 0x00, 0x00,
+            0x2d, 0x23, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x69, 0x12, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x55, 0x02, 0x10, 0x00, 0x08, 0x00, 0x00, 0x00,
+            0x71, 0x12, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x55, 0x02, 0x0e, 0x00, 0x06, 0x00, 0x00, 0x00,
+            0x18, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x79, 0x11, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0xbf, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x57, 0x02, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00,
+            0x15, 0x02, 0x08, 0x00, 0x99, 0x99, 0x00, 0x00,
+            0x18, 0x02, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x5f, 0x21, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0xb7, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
+            0x18, 0x02, 0x00, 0x00, 0x00, 0x00, 0x99, 0x99,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x1d, 0x21, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0xb7, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x95, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+        ];
+        disassembler::disassemble(prog);
+    }
 }
diff --git a/examples/load_elf.rs b/examples/load_elf.rs
@@ -49,85 +49,88 @@ use rbpf::helpers;
 
 fn main() {
 
-    let filename = "examples/load_elf__block_a_port.o";
-
-    let path = PathBuf::from(filename);
-    let file = match elf::File::open_path(path) {
-        Ok(f) => f,
-        Err(e) => panic!("Error: {:?}", e),
-    };
-
-    let text_scn = match file.get_section(".classifier") {
-        Some(s) => s,
-        None => panic!("Failed to look up .classifier section"),
-    };
-
-    let prog = &text_scn.data;
-
-    let packet1 = &mut [
-        0x01, 0x23, 0x45, 0x67, 0x89, 0xab,
-        0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54,
-        0x08, 0x00, // ethertype
-        0x45, 0x00, 0x00, 0x3b, // start ip_hdr
-        0xa6, 0xab, 0x40, 0x00,
-        0x40, 0x06, 0x96, 0x0f,
-        0x7f, 0x00, 0x00, 0x01,
-        0x7f, 0x00, 0x00, 0x01,
-        // Program matches the next two bytes: 0x9999 returns 0xffffffff, else return 0.
-        0x99, 0x99, 0xc6, 0xcc, // start tcp_hdr
-        0xd1, 0xe5, 0xc4, 0x9d,
-        0xd4, 0x30, 0xb5, 0xd2,
-        0x80, 0x18, 0x01, 0x56,
-        0xfe, 0x2f, 0x00, 0x00,
-        0x01, 0x01, 0x08, 0x0a, // start data
-        0x00, 0x23, 0x75, 0x89,
-        0x00, 0x23, 0x63, 0x2d,
-        0x71, 0x64, 0x66, 0x73,
-        0x64, 0x66, 0x0au8
-    ];
-
-    let packet2 = &mut [
-        0x01, 0x23, 0x45, 0x67, 0x89, 0xab,
-        0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54,
-        0x08, 0x00, // ethertype
-        0x45, 0x00, 0x00, 0x3b, // start ip_hdr
-        0xa6, 0xab, 0x40, 0x00,
-        0x40, 0x06, 0x96, 0x0f,
-        0x7f, 0x00, 0x00, 0x01,
-        0x7f, 0x00, 0x00, 0x01,
-        // Program matches the next two bytes: 0x9999 returns 0xffffffff, else return 0.
-        0x98, 0x76, 0xc6, 0xcc, // start tcp_hdr
-        0xd1, 0xe5, 0xc4, 0x9d,
-        0xd4, 0x30, 0xb5, 0xd2,
-        0x80, 0x18, 0x01, 0x56,
-        0xfe, 0x2f, 0x00, 0x00,
-        0x01, 0x01, 0x08, 0x0a, // start data
-        0x00, 0x23, 0x75, 0x89,
-        0x00, 0x23, 0x63, 0x2d,
-        0x71, 0x64, 0x66, 0x73,
-        0x64, 0x66, 0x0au8
-    ];
-
-    let mut vm = rbpf::EbpfVmFixedMbuff::new(Some(prog), 0x40, 0x50).unwrap();
-    vm.register_helper(helpers::BPF_TRACE_PRINTK_IDX, helpers::bpf_trace_printf).unwrap();
-
-    let res = vm.execute_program(packet1).unwrap();
-    println!("Packet #1, program returned: {res:?} ({res:#x})");
-    assert_eq!(res, 0xffffffff);
-
-    #[cfg(all(not(windows), feature = "std"))]
-    {
-        vm.jit_compile().unwrap();
-
-        let res = unsafe { vm.execute_program_jit(packet2).unwrap() };
-        println!("Packet #2, program returned: {res:?} ({res:#x})");
-        assert_eq!(res, 0);
-    }
-
-    #[cfg(any(windows, not(feature = "std")))]
-    {
-        let res = vm.execute_program(packet2).unwrap();
-        println!("Packet #2, program returned: {:?} ({:#x})", res, res);
-        assert_eq!(res, 0);
+    // This example relies on the bpf_trace_printf which is only available on std
+    #[cfg(feature = "std")] {
+        let filename = "examples/load_elf__block_a_port.o";
+
+        let path = PathBuf::from(filename);
+        let file = match elf::File::open_path(path) {
+            Ok(f) => f,
+            Err(e) => panic!("Error: {:?}", e),
+        };
+
+        let text_scn = match file.get_section(".classifier") {
+            Some(s) => s,
+            None => panic!("Failed to look up .classifier section"),
+        };
+
+        let prog = &text_scn.data;
+
+        let packet1 = &mut [
+            0x01, 0x23, 0x45, 0x67, 0x89, 0xab,
+            0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54,
+            0x08, 0x00, // ethertype
+            0x45, 0x00, 0x00, 0x3b, // start ip_hdr
+            0xa6, 0xab, 0x40, 0x00,
+            0x40, 0x06, 0x96, 0x0f,
+            0x7f, 0x00, 0x00, 0x01,
+            0x7f, 0x00, 0x00, 0x01,
+            // Program matches the next two bytes: 0x9999 returns 0xffffffff, else return 0.
+            0x99, 0x99, 0xc6, 0xcc, // start tcp_hdr
+            0xd1, 0xe5, 0xc4, 0x9d,
+            0xd4, 0x30, 0xb5, 0xd2,
+            0x80, 0x18, 0x01, 0x56,
+            0xfe, 0x2f, 0x00, 0x00,
+            0x01, 0x01, 0x08, 0x0a, // start data
+            0x00, 0x23, 0x75, 0x89,
+            0x00, 0x23, 0x63, 0x2d,
+            0x71, 0x64, 0x66, 0x73,
+            0x64, 0x66, 0x0au8
+        ];
+
+        let packet2 = &mut [
+            0x01, 0x23, 0x45, 0x67, 0x89, 0xab,
+            0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54,
+            0x08, 0x00, // ethertype
+            0x45, 0x00, 0x00, 0x3b, // start ip_hdr
+            0xa6, 0xab, 0x40, 0x00,
+            0x40, 0x06, 0x96, 0x0f,
+            0x7f, 0x00, 0x00, 0x01,
+            0x7f, 0x00, 0x00, 0x01,
+            // Program matches the next two bytes: 0x9999 returns 0xffffffff, else return 0.
+            0x98, 0x76, 0xc6, 0xcc, // start tcp_hdr
+            0xd1, 0xe5, 0xc4, 0x9d,
+            0xd4, 0x30, 0xb5, 0xd2,
+            0x80, 0x18, 0x01, 0x56,
+            0xfe, 0x2f, 0x00, 0x00,
+            0x01, 0x01, 0x08, 0x0a, // start data
+            0x00, 0x23, 0x75, 0x89,
+            0x00, 0x23, 0x63, 0x2d,
+            0x71, 0x64, 0x66, 0x73,
+            0x64, 0x66, 0x0au8
+        ];
+
+        let mut vm = rbpf::EbpfVmFixedMbuff::new(Some(prog), 0x40, 0x50).unwrap();
+        vm.register_helper(helpers::BPF_TRACE_PRINTK_IDX, helpers::bpf_trace_printf).unwrap();
+
+        let res = vm.execute_program(packet1).unwrap();
+        println!("Packet #1, program returned: {res:?} ({res:#x})");
+        assert_eq!(res, 0xffffffff);
+
+        #[cfg(not(windows))]
+        {
+            vm.jit_compile().unwrap();
+
+            let res = unsafe { vm.execute_program_jit(packet2).unwrap() };
+            println!("Packet #2, program returned: {res:?} ({res:#x})");
+            assert_eq!(res, 0);
+        }
+
+        #[cfg(windows)]
+        {
+            let res = vm.execute_program(packet2).unwrap();
+            println!("Packet #2, program returned: {:?} ({:#x})", res, res);
+            assert_eq!(res, 0);
+        }
     }
 }