failed to produce bindings for RPM library

[sa2ajj]

I'm looking into creating Rust bindings for the RPM libraries.

First I installed bindgen, but it seems to be somewhat inconsistent with what servo/rust-bindgen offers. So my second attempt was to clone and build bindgen from servo/rust-bindgen:

$ git clone https://github.com/servo/rust-bindgen
$ cd rust-bindgen/bindgen
$ cargo build --release

after that I created a simple wrapper.h:

#include <rpm/rpmlib.h>
#include <rpm/rpmts.h>

and then run bindgen on it:

$ CLANG_PATH=/opt/clang+llvm-3.9.1-x86_64-linux-gnu-debian8/bin/clangLIBCLANG_PATH=/opt/clang+llvm-3.9.1-x86_64-linux-gnu-debian8/lib/ ~/bin/bindgen wrapper.h --output=rpm.rs

as the result I got these errors:

ERROR:libbindgen::ir::context: Valid declaration with no USR: Cursor(__va_list_tag kind: StructDecl, loc: builtin definitions, usr: None), Some(Cursor(va_list kind: TypedefDecl, loc: /opt/clang+llvm-3.9.1-x86_64-linux-gnu-debian8/bin/../lib/clang/3.9.1/include/stdarg.h:30:27, usr: Some("c:@T@va_list")))
ERROR:libbindgen::ir::context: Valid declaration with no USR: Cursor(__builtin_va_list kind: TypedefDecl, loc: builtin definitions, usr: None), Some(Cursor(va_list kind: TypedefDecl, loc: /opt/clang+llvm-3.9.1-x86_64-linux-gnu-debian8/bin/../lib/clang/3.9.1/include/stdarg.h:30:27, usr: Some("c:@T@va_list")))

Do I miss something?

[emilio]

Those errors are non-fatal, does the generated code compile? You can post it here if you want.

If it doesn't, I bet this is #361, and you need to blacklist the functions that use varargs until we do it automatically.

[fitzgen]

We might want to make all the non-fatal error!(...)s into warn!(...)s, because I expect most people get confused. I know I did when I first started using bindgen.

Thoughts @emilio ?

[emilio]

Sounds good to me.

[sa2ajj]

right, since I had no rpm.rs after my previous attempts (for some reason my package installed clang 3.8 was used) I did not check whether the aforementioned file has any content: actually it does.

I tried to compile the produced rpm.rs and it failed: from my inexperienced look, the problems are not related to the issues mentioned in this issue #361. A couple of errors from running rustc on the rpm.rs:

error[E0428]: a type named `poptOption` has already been defined in this module
...
error: unions are unstable and possibly buggy (see issue #32836)
...
error: aborting due to 14 previous errors

and the union related error is the 13 beside the first one.

[sa2ajj]

I forgot to mention:

$ rustc --version
rustc 1.14.0 (e8a012324 2016-12-16)

[emilio]

Ok, so the unions one is that by default we generate rust unions, which are nightly-only right now. We probably should change that default behavior.

Can you call bindgen with --no-unstable-rust, and see if that makes things better? The poptOption error seems interesting.

[sa2ajj]

As you suggested, I run bindgen with --no-unstable-rust option. The compilation of the resulting rpm.rs failed with

error[E0428]: a type named `poptOption` has already been defined in this module
    --> rpm.rs:1246:1
     |   
1176 | pub struct poptOption {
     | - previous definition of `poptOption` here
...
1246 | pub type poptOption = *mut poptOption;
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ already defined

error: main function not found

error[E0391]: unsupported cyclic reference between types/traits detected
    --> rpm.rs:1246:28
     |   
1246 | pub type poptOption = *mut poptOption;
     |                            ^^^^^^^^^^ cyclic reference
     |   
     = note: the cycle begins when processing `poptOption`...
     = note: ...which then again requires processing `poptOption`, completing the cycle.

error: aborting due to previous error

main function not found is understandable, the rest is not that much.

poptOption comes from popt library (#include <popt.h>) and it has this:

struct poptOption {
...
};
...
#ifndef __cplusplus
/*@-exporttype -typeuse@*/
typedef struct poptOption * poptOption;
/*@=exporttype =typeuse@*/
#endif
...

Is C++ somehow controlled by an option?

[emilio]

Yup! passing -x c++ to bindgen like:

./bindgen wrapper.h --output=rpm.rs --no-unstable-rust -- -x c++

Should make it work.

[sa2ajj]

That definitely made a difference. First, the output of bindgen:

ERROR:libbindgen::ir::item: Unhandled cursor kind CXCursorKind(400): Cursor( kind: UnexposedAttr, loc: /usr/lib/gcc/x86_64-linux-gnu/6.2.1/../../../../include/x86_64-linux-gnu/c++/6.2.1/bits/c++config.h:223:43, usr: None)
ERROR:libbindgen::ir::item: Unhandled cursor kind CXCursorKind(400): Cursor( kind: UnexposedAttr, loc: /usr/lib/gcc/x86_64-linux-gnu/6.2.1/../../../../include/x86_64-linux-gnu/c++/6.2.1/bits/c++config.h:227:43, usr: None)
ERROR:libbindgen::ir::item: Unhandled cursor kind CXCursorKind(417): Cursor(default kind: attribute(visibility), loc: /usr/lib/gcc/x86_64-linux-gnu/6.2.1/../../../../include/c++/6.2.1/cstdlib:120:15, usr: None)
ERROR:libbindgen::ir::item: Unhandled cursor kind CXCursorKind(417): Cursor(default kind: attribute(visibility), loc: /usr/lib/gcc/x86_64-linux-gnu/6.2.1/../../../../include/c++/6.2.1/cstdlib:215:21, usr: None)
ERROR:libbindgen::ir::context: Valid declaration with no USR: Cursor(__va_list_tag kind: StructDecl, loc: builtin definitions, usr: None), Some(Cursor(va_list kind: TypedefDecl, loc: /opt/clang+llvm-3.9.1-x86_64-linux-gnu-debian8/bin/../lib/clang/3.9.1/include/stdarg.h:30:27, usr: Some("c:@T@va_list")))
ERROR:libbindgen::ir::context: Valid declaration with no USR: Cursor(__builtin_va_list kind: TypedefDecl, loc: builtin definitions, usr: None), Some(Cursor(va_list kind: TypedefDecl, loc: /opt/clang+llvm-3.9.1-x86_64-linux-gnu-debian8/bin/../lib/clang/3.9.1/include/stdarg.h:30:27, usr: Some("c:@T@va_list")))

and then the output of rustc:

error: main function not found

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5840:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5840 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5848:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5848 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5854:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5854 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5862:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5862 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5868:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5868 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5876:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5876 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5882:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5882 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5890:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5890 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5896:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5896 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5904:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5904 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5910:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5910 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5918:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5918 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5924:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5924 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5932:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5932 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5938:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5938 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5946:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5946 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5952:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5952 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5960:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5960 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `at_offset_0`:
    --> rpm.rs:5966:5
     |
5826 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     - previous definition of `at_offset_0` here
...
5966 |     pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
     |     ^ duplicate definition

error[E0201]: duplicate definitions with name `set_at_offset_0`:
    --> rpm.rs:5974:5
     |
5834 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     - previous definition of `set_at_offset_0` here
...
5974 |     pub fn set_at_offset_0(&mut self, val: ::std::os::raw::c_int) {
     |     ^ duplicate definition

error: aborting due to 20 previous errors

[emilio]

That's... Interesting!

Do you have the definition of the struct that is causing those?

[sa2ajj]

this comes from <bits/timex.h>, I believe, which means that bindgen tries to generate for all things system.

what I want is to generate bindings for rpm related headers only, is there an easy way to do that?

the code rustc complains about:

---

#[repr(C)]
#[derive(Debug, Copy)]
pub struct timex {
    pub modes: ::std::os::raw::c_uint,
    pub offset: __syscall_slong_t,
    pub freq: __syscall_slong_t,
    pub maxerror: __syscall_slong_t,
    pub esterror: __syscall_slong_t,
    pub status: ::std::os::raw::c_int,
    pub constant: __syscall_slong_t,
    pub precision: __syscall_slong_t,
    pub tolerance: __syscall_slong_t,
    pub time: timeval,
    pub tick: __syscall_slong_t,
    pub ppsfreq: __syscall_slong_t,
    pub jitter: __syscall_slong_t,
    pub shift: ::std::os::raw::c_int,
    pub stabil: __syscall_slong_t,
    pub jitcnt: __syscall_slong_t,
    pub calcnt: __syscall_slong_t,
    pub errcnt: __syscall_slong_t,
    pub stbcnt: __syscall_slong_t,
    pub tai: ::std::os::raw::c_int,
    pub _bitfield_1: u32,
    pub _bitfield_2: u32,
    pub _bitfield_3: u32,
    pub _bitfield_4: u32,
    pub _bitfield_5: u32,
    pub _bitfield_6: u32,
    pub _bitfield_7: u32,
    pub _bitfield_8: u32,
    pub _bitfield_9: u32,
    pub _bitfield_10: u32,
    pub _bitfield_11: u32,
}
#[test]
fn bindgen_test_layout_timex() {
    assert_eq!(::std::mem::size_of::<timex>() , 208usize);
    assert_eq!(::std::mem::align_of::<timex>() , 8usize);
}
impl Clone for timex {
    fn clone(&self) -> Self { *self }
}
impl timex {
    #[inline]
    pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
        unsafe {
            ::std::mem::transmute(((self._bitfield_1 &
                                        (4294967295usize as u32)) >> 0u32) as
                                      u32)
        }
    }
    ...
    #[inline]
    pub fn at_offset_0(&self) -> ::std::os::raw::c_int {
        unsafe {
            ::std::mem::transmute(((self._bitfield_2 &
                                        (4294967295usize as u32)) >> 0u32) as
                                      u32)
        }
    }
    ...

[emilio]

Yes, you should whitelist the rpm stuff you want, using regexes.

For example: `--whitelist-function "rpm.*".

[fitzgen]

@sa2ajj are you still hitting this on master? If so, the best way to contribute to resolving this bug would be to create a reduced test case.