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Auto merge of #2144 - kjvalencik:master, r=JohnTitor
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Add dl_iterate_phdr to Android

Adds the `dl_iterate_phdr` function for Android targets. This is required for Android support in `gimli` and by proxy, `backtrace`.

I tested this in [`backtrace`](rust-lang/backtrace-rs#415) both in an i686 emulator and a physical arm64 device.

This API is only available on Version 21+. I'm not sure how that's typically handled in `libc`, so I added a doc comment.

Let me know what else is needed!
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bors committed Apr 12, 2021
2 parents 4d0cd9a + ab1472e commit d3ca6a7
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Showing 2 changed files with 101 additions and 2 deletions.
26 changes: 24 additions & 2 deletions libc-test/build.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1384,11 +1384,13 @@ fn test_android(target: &str) {
"ctype.h",
"dirent.h",
"dlfcn.h",
"elf.h",
"errno.h",
"fcntl.h",
"grp.h",
"ifaddrs.h",
"limits.h",
"link.h",
"locale.h",
"malloc.h",
"net/ethernet.h",
Expand Down Expand Up @@ -1469,6 +1471,7 @@ fn test_android(target: &str) {
"asm/mman.h",
"linux/auxvec.h",
"linux/dccp.h",
"linux/elf.h",
"linux/errqueue.h",
"linux/falloc.h",
"linux/futex.h",
Expand Down Expand Up @@ -1507,7 +1510,7 @@ fn test_android(target: &str) {
cfg.type_name(move |ty, is_struct, is_union| {
match ty {
// Just pass all these through, no need for a "struct" prefix
"FILE" | "fd_set" | "Dl_info" => ty.to_string(),
"FILE" | "fd_set" | "Dl_info" | "Elf32_Phdr" | "Elf64_Phdr" => ty.to_string(),

t if is_union => format!("union {}", t),

Expand Down Expand Up @@ -1610,7 +1613,12 @@ fn test_android(target: &str) {
// This is a weird union, don't check the type.
(struct_ == "ifaddrs" && field == "ifa_ifu") ||
// sigval is actually a union, but we pretend it's a struct
(struct_ == "sigevent" && field == "sigev_value")
(struct_ == "sigevent" && field == "sigev_value") ||
// FIXME: `sa_sigaction` has type `sighandler_t` but that type is
// incorrect, see: https://github.com/rust-lang/libc/issues/1359
(struct_ == "sigaction" && field == "sa_sigaction") ||
// signalfd had SIGSYS fields added in Android 4.19, but CI does not have that version yet.
(struct_ == "signalfd_siginfo" && field == "ssi_call_addr")
});

cfg.skip_field(move |struct_, field| {
Expand All @@ -1628,6 +1636,20 @@ fn test_android(target: &str) {
field == "ssi_arch"))
});

cfg.skip_field(|struct_, field| {
match (struct_, field) {
// conflicting with `p_type` macro from <resolve.h>.
("Elf32_Phdr", "p_type") => true,
("Elf64_Phdr", "p_type") => true,

// this is actually a union on linux, so we can't represent it well and
// just insert some padding.
("siginfo_t", "_pad") => true,

_ => false,
}
});

cfg.generate("../src/lib.rs", "main.rs");

test_linux_like_apis(target);
Expand Down
77 changes: 77 additions & 0 deletions src/unix/linux_like/android/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,19 @@ pub type loff_t = ::c_longlong;
pub type __kernel_loff_t = ::c_longlong;
pub type __kernel_pid_t = ::c_int;

// linux/elf.h

pub type Elf32_Addr = u32;
pub type Elf32_Half = u16;
pub type Elf32_Off = u32;
pub type Elf32_Word = u32;

pub type Elf64_Addr = u64;
pub type Elf64_Half = u16;
pub type Elf64_Off = u64;
pub type Elf64_Word = u32;
pub type Elf64_Xword = u64;

s! {
pub struct stack_t {
pub ss_sp: *mut ::c_void,
Expand Down Expand Up @@ -244,6 +257,57 @@ s! {
pub svm_cid: ::c_uint,
pub svm_zero: [u8; 4]
}

// linux/elf.h

pub struct Elf32_Phdr {
pub p_type: Elf32_Word,
pub p_offset: Elf32_Off,
pub p_vaddr: Elf32_Addr,
pub p_paddr: Elf32_Addr,
pub p_filesz: Elf32_Word,
pub p_memsz: Elf32_Word,
pub p_flags: Elf32_Word,
pub p_align: Elf32_Word,
}

pub struct Elf64_Phdr {
pub p_type: Elf64_Word,
pub p_flags: Elf64_Word,
pub p_offset: Elf64_Off,
pub p_vaddr: Elf64_Addr,
pub p_paddr: Elf64_Addr,
pub p_filesz: Elf64_Xword,
pub p_memsz: Elf64_Xword,
pub p_align: Elf64_Xword,
}

// link.h

pub struct dl_phdr_info {
#[cfg(target_pointer_width = "64")]
pub dlpi_addr: Elf64_Addr,
#[cfg(target_pointer_width = "32")]
pub dlpi_addr: Elf32_Addr,

pub dlpi_name: *const ::c_char,

#[cfg(target_pointer_width = "64")]
pub dlpi_phdr: *const Elf64_Phdr,
#[cfg(target_pointer_width = "32")]
pub dlpi_phdr: *const Elf32_Phdr,

#[cfg(target_pointer_width = "64")]
pub dlpi_phnum: Elf64_Half,
#[cfg(target_pointer_width = "32")]
pub dlpi_phnum: Elf32_Half,

// These fields were added in Android R
pub dlpi_adds: ::c_ulonglong,
pub dlpi_subs: ::c_ulonglong,
pub dlpi_tls_modid: ::size_t,
pub dlpi_tls_data: *mut ::c_void,
}
}

s_no_extra_traits! {
Expand Down Expand Up @@ -2715,6 +2779,19 @@ extern "C" {

pub fn __system_property_set(__name: *const ::c_char, __value: *const ::c_char) -> ::c_int;
pub fn __system_property_get(__name: *const ::c_char, __value: *mut ::c_char) -> ::c_int;

// #include <link.h>
/// Only available in API Version 21+
pub fn dl_iterate_phdr(
callback: ::Option<
unsafe extern "C" fn(
info: *mut dl_phdr_info,
size: usize,
data: *mut ::c_void,
) -> ::c_int,
>,
data: *mut ::c_void,
) -> ::c_int;
}

cfg_if! {
Expand Down

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