linux(uclibc): change file offset bindings

The currently exposed bindings to file offset types and routines are
often found to be either lacking or incorrect in the current worktree.
This has been fixed by means of changing multiple type definitions
across child modules of the `linux/uclibc` module, such that a more
cohesive interface is exposed.

Types with LFS64 variants in 32-bit platforms will now have equivalent
definitions to their "unsuffixed" variants if the
`uclibc_file_offset_bits` `cfg` is set. In 64-bit machine word targets,
both the unsuffixed and suffixed types are unconditionally exposed with
the same bit width.

Author: dybucc

build.rs

@@ -35,6 +35,8 @@ const ALLOWED_CFGS: &[&str] = &[
     // Corresponds to `_REDIR_TIME64` in musl: symbol redirects to __*_time64
     "musl_redir_time64",
     "vxworks_lt_25_09",
+    // Corresponds with `__USE_FILE_OFFSET64` in uClibc.
+    "uclibc_file_offset_bits64",
 ];
 
 // Extra values to allow for check-cfg.
@@ -131,11 +133,6 @@ fn main() {
         }
     }
 
-    let uclibc_use_time64 = env_flag("CARGO_CFG_LIBC_UNSTABLE_UCLIBC_TIME64");
-    if target_env == "uclibc" && uclibc_use_time64 {
-        set_cfg("linux_time_bits64");
-    }
-
     let linux_time_bits64 = env::var("RUST_LIBC_UNSTABLE_LINUX_TIME_BITS64").is_ok();
     println!("cargo:rerun-if-env-changed=RUST_LIBC_UNSTABLE_LINUX_TIME_BITS64");
     if linux_time_bits64 {
@@ -180,6 +177,13 @@ fn main() {
         }
     }
 
+    if target_env == "uclibc"
+        && target_ptr_width == "32"
+        && env::var("CARGO_CFG_LIBC_UNSTABLE_UCLIBC_FILE_OFFSET_BITS").is_ok()
+    {
+        set_cfg("uclibc_file_offset_bits64");
+    }
+
     // On CI: deny all warnings
     if libc_ci {
         set_cfg("libc_deny_warnings");

src/unix/linux_like/linux/uclibc/arm/mod.rs

@@ -1,4 +1,3 @@
-use crate::off64_t;
 use crate::prelude::*;
 
 pub type wchar_t = c_uint;
@@ -15,22 +14,23 @@ cfg_if! {
 }
 
 pub type clock_t = c_long;
-pub type fsblkcnt_t = c_ulong;
-pub type fsfilcnt_t = c_ulong;
-pub type ino_t = c_ulong;
-pub type off_t = c_long;
 pub type pthread_t = c_ulong;
 
 pub type nlink_t = c_uint;
 pub type blksize_t = c_long;
-pub type blkcnt_t = c_long;
 
-pub type fsblkcnt64_t = u64;
-pub type fsfilcnt64_t = u64;
 pub type __u64 = c_ulonglong;
 pub type __s64 = c_longlong;
 
 s! {
+    pub struct flock {
+        pub l_type: c_short,
+        pub l_whence: c_short,
+        pub l_start: crate::off_t,
+        pub l_len: crate::off_t,
+        pub l_pid: crate::pid_t,
+    }
+
     pub struct cmsghdr {
         pub cmsg_len: size_t,
         pub cmsg_level: c_int,
@@ -52,58 +52,71 @@ s! {
     }
 
     pub struct stat {
-        pub st_dev: c_ulonglong,
+        pub st_dev: crate::dev_t,
+
+        #[cfg(not(uclibc_file_offset_bits64))]
         __pad1: Padding<c_ushort>,
+        #[cfg(not(uclibc_file_offset_bits64))]
         pub st_ino: crate::ino_t,
+
+        #[cfg(uclibc_file_offset_bits64)]
+        __pad1: Padding<c_uint>,
+        #[cfg(uclibc_file_offset_bits64)]
+        pub __st_ino: crate::ino_t,
+
         pub st_mode: crate::mode_t,
         pub st_nlink: crate::nlink_t,
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
-        pub st_rdev: c_ulonglong,
+        pub st_rdev: crate::dev_t,
+
+        #[cfg(not(uclibc_file_offset_bits64))]
         __pad2: Padding<c_ushort>,
-        pub st_size: off_t,
+
+        #[cfg(uclibc_file_offset_bits64)]
+        __pad2: Padding<c_uint>,
+
+        pub st_size: crate::off_t,
         pub st_blksize: crate::blksize_t,
         pub st_blocks: crate::blkcnt_t,
         pub st_atime: crate::time_t,
-        pub st_atime_nsec: c_long,
+        pub st_atime_nsec: c_ulong,
         pub st_mtime: crate::time_t,
-        pub st_mtime_nsec: c_long,
+        pub st_mtime_nsec: c_ulong,
         pub st_ctime: crate::time_t,
-        pub st_ctime_nsec: c_long,
-        __unused4: Padding<c_ulong>,
-        __unused5: Padding<c_ulong>,
+        pub st_ctime_nsec: c_ulong,
+
+        #[cfg(not(uclibc_file_offset_bits64))]
+        __uclibc_unused4: Padding<c_ulong>,
+        #[cfg(not(uclibc_file_offset_bits64))]
+        __uclibc_unused5: Padding<c_ulong>,
+
+        #[cfg(uclibc_file_offset_bits64)]
+        pub st_ino: crate::ino_t,
     }
 
     pub struct stat64 {
-        pub st_dev: c_ulonglong,
-        pub __pad1: c_uint,
+        pub st_dev: crate::dev_t,
+        __pad1: Padding<c_uint>,
         pub __st_ino: crate::ino_t,
         pub st_mode: crate::mode_t,
         pub st_nlink: crate::nlink_t,
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
-        pub st_rdev: c_ulonglong,
-        pub __pad2: c_uint,
-        pub st_size: off64_t,
+        pub st_rdev: crate::dev_t,
+        __pad2: Padding<c_uint>,
+        pub st_size: crate::off64_t,
         pub st_blksize: crate::blksize_t,
         pub st_blocks: crate::blkcnt64_t,
         pub st_atime: crate::time_t,
-        pub st_atime_nsec: c_long,
+        pub st_atime_nsec: c_ulong,
         pub st_mtime: crate::time_t,
-        pub st_mtime_nsec: c_long,
+        pub st_mtime_nsec: c_ulong,
         pub st_ctime: crate::time_t,
-        pub st_ctime_nsec: c_long,
+        pub st_ctime_nsec: c_ulong,
         pub st_ino: crate::ino64_t,
     }
 
-    pub struct flock {
-        pub l_type: c_short,
-        pub l_whence: c_short,
-        pub l_start: off_t,
-        pub l_len: off_t,
-        pub l_pid: crate::pid_t,
-    }
-
     pub struct sysinfo {
         pub uptime: c_long,
         pub loads: [c_ulong; 3],
@@ -134,7 +147,7 @@ s! {
         pub f_namelen: c_int,
         pub f_frsize: c_int,
         pub f_flags: c_int,
-        pub f_spare: [c_int; 4],
+        f_spare: Padding<[c_int; 4]>,
     }
 
     pub struct statfs64 {
@@ -145,27 +158,12 @@ s! {
         pub f_bavail: crate::fsblkcnt64_t,
         pub f_files: crate::fsfilcnt64_t,
         pub f_ffree: crate::fsfilcnt64_t,
+
         pub f_fsid: crate::fsid_t,
         pub f_namelen: c_int,
         pub f_frsize: c_int,
         pub f_flags: c_int,
-        pub f_spare: [c_int; 4],
-    }
-
-    pub struct statvfs64 {
-        pub f_bsize: c_ulong,
-        pub f_frsize: c_ulong,
-        pub f_blocks: u64,
-        pub f_bfree: u64,
-        pub f_bavail: u64,
-        pub f_files: u64,
-        pub f_ffree: u64,
-        pub f_favail: u64,
-        pub f_fsid: c_ulong,
-        __f_unused: Padding<c_int>,
-        pub f_flag: c_ulong,
-        pub f_namemax: c_ulong,
-        __f_spare: [c_int; 6],
+        f_spare: Padding<[c_int; 4]>,
     }
 
     pub struct sigset_t {

src/unix/linux_like/linux/uclibc/mips/mips32/mod.rs

@@ -1,21 +1,13 @@
-use crate::off64_t;
 use crate::prelude::*;
 
 pub type clock_t = i32;
 pub type time_t = i32;
 pub type suseconds_t = i32;
 pub type wchar_t = i32;
-pub type off_t = i32;
-pub type ino_t = u32;
-pub type blkcnt_t = i32;
 pub type blksize_t = i32;
 pub type nlink_t = u32;
-pub type fsblkcnt_t = c_ulong;
-pub type fsfilcnt_t = c_ulong;
 pub type __u64 = c_ulonglong;
 pub type __s64 = c_longlong;
-pub type fsblkcnt64_t = u64;
-pub type fsfilcnt64_t = u64;
 
 s! {
     pub struct stat {
@@ -27,16 +19,29 @@ s! {
         pub st_uid: crate::uid_t,
         pub st_gid: crate::gid_t,
         pub st_rdev: crate::dev_t,
-        pub st_pad2: [c_long; 1],
-        pub st_size: off_t,
+
+        #[cfg(not(uclibc_file_offset_bits64))]
+        st_pad2: Padding<[c_long; 1]>,
+
+        #[cfg(uclibc_file_offset_bits64)]
+        st_pad2: Padding<[c_long; 2]>,
+
+        pub st_size: crate::off_t,
+
+        #[cfg(not(uclibc_file_offset_bits64))]
         st_pad3: Padding<c_long>,
+
         pub st_atime: crate::time_t,
-        pub st_atime_nsec: c_long,
+        pub st_atime_nsec: c_ulong,
         pub st_mtime: crate::time_t,
-        pub st_mtime_nsec: c_long,
+        pub st_mtime_nsec: c_ulong,
         pub st_ctime: crate::time_t,
-        pub st_ctime_nsec: c_long,
+        pub st_ctime_nsec: c_ulong,
         pub st_blksize: crate::blksize_t,
+
+        #[cfg(uclibc_file_offset_bits64)]
+        st_pad4: Padding<c_long>,
+
         pub st_blocks: crate::blkcnt_t,
         st_pad5: Padding<[c_long; 14]>,
     }
@@ -51,33 +56,17 @@ s! {
         pub st_gid: crate::gid_t,
         pub st_rdev: crate::dev_t,
         st_pad2: Padding<[c_long; 2]>,
-        pub st_size: off64_t,
+        pub st_size: crate::off64_t,
         pub st_atime: crate::time_t,
-        pub st_atime_nsec: c_long,
+        pub st_atime_nsec: c_ulong,
         pub st_mtime: crate::time_t,
-        pub st_mtime_nsec: c_long,
+        pub st_mtime_nsec: c_ulong,
         pub st_ctime: crate::time_t,
-        pub st_ctime_nsec: c_long,
+        pub st_ctime_nsec: c_ulong,
         pub st_blksize: crate::blksize_t,
         st_pad3: Padding<c_long>,
         pub st_blocks: crate::blkcnt64_t,
-        st_pad5: Padding<[c_long; 14]>,
-    }
-
-    pub struct statvfs64 {
-        pub f_bsize: c_ulong,
-        pub f_frsize: c_ulong,
-        pub f_blocks: crate::fsblkcnt64_t,
-        pub f_bfree: crate::fsblkcnt64_t,
-        pub f_bavail: crate::fsblkcnt64_t,
-        pub f_files: crate::fsfilcnt64_t,
-        pub f_ffree: crate::fsfilcnt64_t,
-        pub f_favail: crate::fsfilcnt64_t,
-        pub f_fsid: c_ulong,
-        pub __f_unused: c_int,
-        pub f_flag: c_ulong,
-        pub f_namemax: c_ulong,
-        pub __f_spare: [c_int; 6],
+        st_pad4: Padding<[c_long; 14]>,
     }
 
     pub struct pthread_attr_t {
@@ -173,36 +162,6 @@ s! {
         __glibc_reserved5: Padding<c_ulong>,
     }
 
-    pub struct statfs {
-        pub f_type: c_long,
-        pub f_bsize: c_long,
-        pub f_frsize: c_long,
-        pub f_blocks: crate::fsblkcnt_t,
-        pub f_bfree: crate::fsblkcnt_t,
-        pub f_files: crate::fsblkcnt_t,
-        pub f_ffree: crate::fsblkcnt_t,
-        pub f_bavail: crate::fsblkcnt_t,
-        pub f_fsid: crate::fsid_t,
-
-        pub f_namelen: c_long,
-        f_spare: [c_long; 6],
-    }
-
-    pub struct statfs64 {
-        pub f_type: c_long,
-        pub f_bsize: c_long,
-        pub f_frsize: c_long,
-        pub f_blocks: crate::fsblkcnt64_t,
-        pub f_bfree: crate::fsblkcnt64_t,
-        pub f_files: crate::fsblkcnt64_t,
-        pub f_ffree: crate::fsblkcnt64_t,
-        pub f_bavail: crate::fsblkcnt64_t,
-        pub f_fsid: crate::fsid_t,
-        pub f_namelen: c_long,
-        pub f_flags: c_long,
-        pub f_spare: [c_long; 5],
-    }
-
     pub struct msghdr {
         pub msg_name: *mut c_void,
         pub msg_namelen: crate::socklen_t,
@@ -228,16 +187,6 @@ s! {
         pub c_cc: [crate::cc_t; crate::NCCS],
     }
 
-    pub struct flock {
-        pub l_type: c_short,
-        pub l_whence: c_short,
-        pub l_start: off_t,
-        pub l_len: off_t,
-        pub l_sysid: c_long,
-        pub l_pid: crate::pid_t,
-        pad: Padding<[c_long; 4]>,
-    }
-
     pub struct sysinfo {
         pub uptime: c_long,
         pub loads: [c_ulong; 3],
@@ -665,7 +614,6 @@ pub const SYS_process_mrelease: c_long = 4000 + 448;
 pub const SYS_futex_waitv: c_long = 4000 + 449;
 pub const SYS_set_mempolicy_home_node: c_long = 4000 + 450;
 
-#[link(name = "util")]
 extern "C" {
     pub fn sysctl(
         name: *mut c_int,