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zig/lib/std/zig/system/NativeTargetInfo.zig
Stephen Gregoratto 285970982a Add illumos OS tag 
- Adds `illumos` to the `Target.Os.Tag` enum. A new function,
  `isSolarish` has been added that returns true if the tag is either
  Solaris or Illumos. This matches the naming convention found in Rust's
  `libc` crate[1].
- Add the tag wherever `.solaris` is being checked against.
- Check for the C pre-processor macro `__illumos__` in CMake to set the
  proper target tuple. Illumos distros patch their compilers to have
  this in the "built-in" set (verified with `echo | cc -dM -E -`).

  Alternatively you could check the output of `uname -o`.

Right now, both Solaris and Illumos import from `c/solaris.zig`. In the
future it may be worth putting the shared ABI bits in a base file, and
mixing that in with specific `c/solaris.zig`/`c/illumos.zig` files.

[1]: 6e02a329a2/src/unix/solarish
2023-10-02 15:31:49 -06:00

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const std = @import("../../std.zig");
const builtin = @import("builtin");
const mem = std.mem;
const assert = std.debug.assert;
const fs = std.fs;
const elf = std.elf;
const native_endian = builtin.cpu.arch.endian();
const NativeTargetInfo = @This();
const Target = std.Target;
const Allocator = std.mem.Allocator;
const CrossTarget = std.zig.CrossTarget;
const windows = std.zig.system.windows;
const darwin = std.zig.system.darwin;
const linux = std.zig.system.linux;
target: Target,
dynamic_linker: DynamicLinker = DynamicLinker{},
pub const DynamicLinker = Target.DynamicLinker;
pub const DetectError = error{
FileSystem,
SystemResources,
SymLinkLoop,
ProcessFdQuotaExceeded,
SystemFdQuotaExceeded,
DeviceBusy,
OSVersionDetectionFail,
Unexpected,
};
/// Given a `CrossTarget`, which specifies in detail which parts of the target should be detected
/// natively, which should be standard or default, and which are provided explicitly, this function
/// resolves the native components by detecting the native system, and then resolves standard/default parts
/// relative to that.
pub fn detect(cross_target: CrossTarget) DetectError!NativeTargetInfo {
var os = cross_target.getOsTag().defaultVersionRange(cross_target.getCpuArch());
if (cross_target.os_tag == null) {
switch (builtin.target.os.tag) {
.linux => {
const uts = std.os.uname();
const release = mem.sliceTo(&uts.release, 0);
// The release field sometimes has a weird format,
// `Version.parse` will attempt to find some meaningful interpretation.
if (std.SemanticVersion.parse(release)) |ver| {
os.version_range.linux.range.min = ver;
os.version_range.linux.range.max = ver;
} else |err| switch (err) {
error.Overflow => {},
error.InvalidVersion => {},
}
},
.solaris, .illumos => {
const uts = std.os.uname();
const release = mem.sliceTo(&uts.release, 0);
if (std.SemanticVersion.parse(release)) |ver| {
os.version_range.semver.min = ver;
os.version_range.semver.max = ver;
} else |err| switch (err) {
error.Overflow => {},
error.InvalidVersion => {},
}
},
.windows => {
const detected_version = windows.detectRuntimeVersion();
os.version_range.windows.min = detected_version;
os.version_range.windows.max = detected_version;
},
.macos => try darwin.macos.detect(&os),
.freebsd, .netbsd, .dragonfly => {
const key = switch (builtin.target.os.tag) {
.freebsd => "kern.osreldate",
.netbsd, .dragonfly => "kern.osrevision",
else => unreachable,
};
var value: u32 = undefined;
var len: usize = @sizeOf(@TypeOf(value));
std.os.sysctlbynameZ(key, &value, &len, null, 0) catch |err| switch (err) {
error.NameTooLong => unreachable, // constant, known good value
error.PermissionDenied => unreachable, // only when setting values,
error.SystemResources => unreachable, // memory already on the stack
error.UnknownName => unreachable, // constant, known good value
error.Unexpected => return error.OSVersionDetectionFail,
};
switch (builtin.target.os.tag) {
.freebsd => {
// https://www.freebsd.org/doc/en_US.ISO8859-1/books/porters-handbook/versions.html
// Major * 100,000 has been convention since FreeBSD 2.2 (1997)
// Minor * 1(0),000 summed has been convention since FreeBSD 2.2 (1997)
// e.g. 492101 = 4.11-STABLE = 4.(9+2)
const major = value / 100_000;
const minor1 = value % 100_000 / 10_000; // usually 0 since 5.1
const minor2 = value % 10_000 / 1_000; // 0 before 5.1, minor version since
const patch = value % 1_000;
os.version_range.semver.min = .{ .major = major, .minor = minor1 + minor2, .patch = patch };
os.version_range.semver.max = os.version_range.semver.min;
},
.netbsd => {
// #define __NetBSD_Version__ MMmmrrpp00
//
// M = major version
// m = minor version; a minor number of 99 indicates current.
// r = 0 (*)
// p = patchlevel
const major = value / 100_000_000;
const minor = value % 100_000_000 / 1_000_000;
const patch = value % 10_000 / 100;
os.version_range.semver.min = .{ .major = major, .minor = minor, .patch = patch };
os.version_range.semver.max = os.version_range.semver.min;
},
.dragonfly => {
// https://github.com/DragonFlyBSD/DragonFlyBSD/blob/cb2cde83771754aeef9bb3251ee48959138dec87/Makefile.inc1#L15-L17
// flat base10 format: Mmmmpp
// M = major
// m = minor; odd-numbers indicate current dev branch
// p = patch
const major = value / 100_000;
const minor = value % 100_000 / 100;
const patch = value % 100;
os.version_range.semver.min = .{ .major = major, .minor = minor, .patch = patch };
os.version_range.semver.max = os.version_range.semver.min;
},
else => unreachable,
}
},
.openbsd => {
const mib: [2]c_int = [_]c_int{
std.os.CTL.KERN,
std.os.KERN.OSRELEASE,
};
var buf: [64]u8 = undefined;
// consider that sysctl result includes null-termination
// reserve 1 byte to ensure we never overflow when appending ".0"
var len: usize = buf.len - 1;
std.os.sysctl(&mib, &buf, &len, null, 0) catch |err| switch (err) {
error.NameTooLong => unreachable, // constant, known good value
error.PermissionDenied => unreachable, // only when setting values,
error.SystemResources => unreachable, // memory already on the stack
error.UnknownName => unreachable, // constant, known good value
error.Unexpected => return error.OSVersionDetectionFail,
};
// append ".0" to satisfy semver
buf[len - 1] = '.';
buf[len] = '0';
len += 1;
if (std.SemanticVersion.parse(buf[0..len])) |ver| {
os.version_range.semver.min = ver;
os.version_range.semver.max = ver;
} else |_| {
return error.OSVersionDetectionFail;
}
},
else => {
// Unimplemented, fall back to default version range.
},
}
}
if (cross_target.os_version_min) |min| switch (min) {
.none => {},
.semver => |semver| switch (cross_target.getOsTag()) {
.linux => os.version_range.linux.range.min = semver,
else => os.version_range.semver.min = semver,
},
.windows => |win_ver| os.version_range.windows.min = win_ver,
};
if (cross_target.os_version_max) |max| switch (max) {
.none => {},
.semver => |semver| switch (cross_target.getOsTag()) {
.linux => os.version_range.linux.range.max = semver,
else => os.version_range.semver.max = semver,
},
.windows => |win_ver| os.version_range.windows.max = win_ver,
};
if (cross_target.glibc_version) |glibc| {
assert(cross_target.isGnuLibC());
os.version_range.linux.glibc = glibc;
}
// Until https://github.com/ziglang/zig/issues/4592 is implemented (support detecting the
// native CPU architecture as being different than the current target), we use this:
const cpu_arch = cross_target.getCpuArch();
var cpu = switch (cross_target.cpu_model) {
.native => detectNativeCpuAndFeatures(cpu_arch, os, cross_target),
.baseline => Target.Cpu.baseline(cpu_arch),
.determined_by_cpu_arch => if (cross_target.cpu_arch == null)
detectNativeCpuAndFeatures(cpu_arch, os, cross_target)
else
Target.Cpu.baseline(cpu_arch),
.explicit => |model| model.toCpu(cpu_arch),
} orelse backup_cpu_detection: {
break :backup_cpu_detection Target.Cpu.baseline(cpu_arch);
};
var result = try detectAbiAndDynamicLinker(cpu, os, cross_target);
// For x86, we need to populate some CPU feature flags depending on architecture
// and mode:
// * 16bit_mode => if the abi is code16
// * 32bit_mode => if the arch is x86
// However, the "mode" flags can be used as overrides, so if the user explicitly
// sets one of them, that takes precedence.
switch (cpu_arch) {
.x86 => {
if (!std.Target.x86.featureSetHasAny(cross_target.cpu_features_add, .{
.@"16bit_mode", .@"32bit_mode",
})) {
switch (result.target.abi) {
.code16 => result.target.cpu.features.addFeature(
@intFromEnum(std.Target.x86.Feature.@"16bit_mode"),
),
else => result.target.cpu.features.addFeature(
@intFromEnum(std.Target.x86.Feature.@"32bit_mode"),
),
}
}
},
.arm, .armeb => {
// XXX What do we do if the target has the noarm feature?
// What do we do if the user specifies +thumb_mode?
},
.thumb, .thumbeb => {
result.target.cpu.features.addFeature(
@intFromEnum(std.Target.arm.Feature.thumb_mode),
);
},
else => {},
}
cross_target.updateCpuFeatures(&result.target.cpu.features);
return result;
}
/// In the past, this function attempted to use the executable's own binary if it was dynamically
/// linked to answer both the C ABI question and the dynamic linker question. However, this
/// could be problematic on a system that uses a RUNPATH for the compiler binary, locking
/// it to an older glibc version, while system binaries such as /usr/bin/env use a newer glibc
/// version. The problem is that libc.so.6 glibc version will match that of the system while
/// the dynamic linker will match that of the compiler binary. Executables with these versions
/// mismatching will fail to run.
///
/// Therefore, this function works the same regardless of whether the compiler binary is
/// dynamically or statically linked. It inspects `/usr/bin/env` as an ELF file to find the
/// answer to these questions, or if there is a shebang line, then it chases the referenced
/// file recursively. If that does not provide the answer, then the function falls back to
/// defaults.
fn detectAbiAndDynamicLinker(
cpu: Target.Cpu,
os: Target.Os,
cross_target: CrossTarget,
) DetectError!NativeTargetInfo {
const native_target_has_ld = comptime builtin.target.hasDynamicLinker();
const is_linux = builtin.target.os.tag == .linux;
const is_solarish = builtin.target.os.tag.isSolarish();
const have_all_info = cross_target.dynamic_linker.get() != null and
cross_target.abi != null and (!is_linux or cross_target.abi.?.isGnu());
const os_is_non_native = cross_target.os_tag != null;
// The Solaris/illumos environment is always the same.
if (!native_target_has_ld or have_all_info or os_is_non_native or is_solarish) {
return defaultAbiAndDynamicLinker(cpu, os, cross_target);
}
if (cross_target.abi) |abi| {
if (abi.isMusl()) {
// musl implies static linking.
return defaultAbiAndDynamicLinker(cpu, os, cross_target);
}
}
// The current target's ABI cannot be relied on for this. For example, we may build the zig
// compiler for target riscv64-linux-musl and provide a tarball for users to download.
// A user could then run that zig compiler on riscv64-linux-gnu. This use case is well-defined
// and supported by Zig. But that means that we must detect the system ABI here rather than
// relying on `builtin.target`.
const all_abis = comptime blk: {
assert(@intFromEnum(Target.Abi.none) == 0);
const fields = std.meta.fields(Target.Abi)[1..];
var array: [fields.len]Target.Abi = undefined;
inline for (fields, 0..) |field, i| {
array[i] = @field(Target.Abi, field.name);
}
break :blk array;
};
var ld_info_list_buffer: [all_abis.len]LdInfo = undefined;
var ld_info_list_len: usize = 0;
const ofmt = cross_target.ofmt orelse Target.ObjectFormat.default(os.tag, cpu.arch);
for (all_abis) |abi| {
// This may be a nonsensical parameter. We detect this with
// error.UnknownDynamicLinkerPath and skip adding it to `ld_info_list`.
const target: Target = .{
.cpu = cpu,
.os = os,
.abi = abi,
.ofmt = ofmt,
};
const ld = target.standardDynamicLinkerPath();
if (ld.get() == null) continue;
ld_info_list_buffer[ld_info_list_len] = .{
.ld = ld,
.abi = abi,
};
ld_info_list_len += 1;
}
const ld_info_list = ld_info_list_buffer[0..ld_info_list_len];
// Best case scenario: the executable is dynamically linked, and we can iterate
// over our own shared objects and find a dynamic linker.
const elf_file = blk: {
// This block looks for a shebang line in /usr/bin/env,
// if it finds one, then instead of using /usr/bin/env as the ELF file to examine, it uses the file it references instead,
// doing the same logic recursively in case it finds another shebang line.
// Since /usr/bin/env is hard-coded into the shebang line of many portable scripts, it's a
// reasonably reliable path to start with.
var file_name: []const u8 = "/usr/bin/env";
// #! (2) + 255 (max length of shebang line since Linux 5.1) + \n (1)
var buffer: [258]u8 = undefined;
while (true) {
const file = fs.openFileAbsolute(file_name, .{}) catch |err| switch (err) {
error.NoSpaceLeft => unreachable,
error.NameTooLong => unreachable,
error.PathAlreadyExists => unreachable,
error.SharingViolation => unreachable,
error.InvalidUtf8 => unreachable,
error.BadPathName => unreachable,
error.PipeBusy => unreachable,
error.FileLocksNotSupported => unreachable,
error.WouldBlock => unreachable,
error.FileBusy => unreachable, // opened without write permissions
error.IsDir,
error.NotDir,
error.InvalidHandle,
error.AccessDenied,
error.NoDevice,
error.FileNotFound,
error.NetworkNotFound,
error.FileTooBig,
error.Unexpected,
=> |e| {
std.log.warn("Encountered error: {s}, falling back to default ABI and dynamic linker.\n", .{@errorName(e)});
return defaultAbiAndDynamicLinker(cpu, os, cross_target);
},
else => |e| return e,
};
errdefer file.close();
const len = preadMin(file, &buffer, 0, buffer.len) catch |err| switch (err) {
error.UnexpectedEndOfFile,
error.UnableToReadElfFile,
=> break :blk file,
else => |e| return e,
};
const newline = mem.indexOfScalar(u8, buffer[0..len], '\n') orelse break :blk file;
const line = buffer[0..newline];
if (!mem.startsWith(u8, line, "#!")) break :blk file;
var it = mem.tokenizeScalar(u8, line[2..], ' ');
file_name = it.next() orelse return defaultAbiAndDynamicLinker(cpu, os, cross_target);
file.close();
}
};
defer elf_file.close();
// If Zig is statically linked, such as via distributed binary static builds, the above
// trick (block self_exe) won't work. The next thing we fall back to is the same thing, but for elf_file.
// TODO: inline this function and combine the buffer we already read above to find
// the possible shebang line with the buffer we use for the ELF header.
return abiAndDynamicLinkerFromFile(elf_file, cpu, os, ld_info_list, cross_target) catch |err| switch (err) {
error.FileSystem,
error.SystemResources,
error.SymLinkLoop,
error.ProcessFdQuotaExceeded,
error.SystemFdQuotaExceeded,
=> |e| return e,
error.UnableToReadElfFile,
error.InvalidElfClass,
error.InvalidElfVersion,
error.InvalidElfEndian,
error.InvalidElfFile,
error.InvalidElfMagic,
error.Unexpected,
error.UnexpectedEndOfFile,
error.NameTooLong,
// Finally, we fall back on the standard path.
=> |e| {
std.log.warn("Encountered error: {s}, falling back to default ABI and dynamic linker.\n", .{@errorName(e)});
return defaultAbiAndDynamicLinker(cpu, os, cross_target);
},
};
}
fn glibcVerFromRPath(rpath: []const u8) !std.SemanticVersion {
var dir = fs.cwd().openDir(rpath, .{}) catch |err| switch (err) {
error.NameTooLong => unreachable,
error.InvalidUtf8 => unreachable,
error.BadPathName => unreachable,
error.DeviceBusy => unreachable,
error.NetworkNotFound => unreachable, // Windows-only
error.FileNotFound,
error.NotDir,
error.InvalidHandle,
error.AccessDenied,
error.NoDevice,
=> return error.GLibCNotFound,
error.ProcessFdQuotaExceeded,
error.SystemFdQuotaExceeded,
error.SystemResources,
error.SymLinkLoop,
error.Unexpected,
=> |e| return e,
};
defer dir.close();
// Now we have a candidate for the path to libc shared object. In
// the past, we used readlink() here because the link name would
// reveal the glibc version. However, in more recent GNU/Linux
// installations, there is no symlink. Thus we instead use a more
// robust check of opening the libc shared object and looking at the
// .dynstr section, and finding the max version number of symbols
// that start with "GLIBC_2.".
const glibc_so_basename = "libc.so.6";
var f = dir.openFile(glibc_so_basename, .{}) catch |err| switch (err) {
error.NameTooLong => unreachable,
error.InvalidUtf8 => unreachable, // Windows only
error.BadPathName => unreachable, // Windows only
error.PipeBusy => unreachable, // Windows-only
error.SharingViolation => unreachable, // Windows-only
error.NetworkNotFound => unreachable, // Windows-only
error.FileLocksNotSupported => unreachable, // No lock requested.
error.NoSpaceLeft => unreachable, // read-only
error.PathAlreadyExists => unreachable, // read-only
error.DeviceBusy => unreachable, // read-only
error.FileBusy => unreachable, // read-only
error.InvalidHandle => unreachable, // should not be in the error set
error.WouldBlock => unreachable, // not using O_NONBLOCK
error.NoDevice => unreachable, // not asking for a special device
error.AccessDenied,
error.FileNotFound,
error.NotDir,
error.IsDir,
=> return error.GLibCNotFound,
error.FileTooBig => return error.Unexpected,
error.ProcessFdQuotaExceeded,
error.SystemFdQuotaExceeded,
error.SystemResources,
error.SymLinkLoop,
error.Unexpected,
=> |e| return e,
};
defer f.close();
return glibcVerFromSoFile(f) catch |err| switch (err) {
error.InvalidElfMagic,
error.InvalidElfEndian,
error.InvalidElfClass,
error.InvalidElfFile,
error.InvalidElfVersion,
error.InvalidGnuLibCVersion,
error.UnexpectedEndOfFile,
=> return error.GLibCNotFound,
error.SystemResources,
error.UnableToReadElfFile,
error.Unexpected,
error.FileSystem,
=> |e| return e,
};
}
fn glibcVerFromSoFile(file: fs.File) !std.SemanticVersion {
var hdr_buf: [@sizeOf(elf.Elf64_Ehdr)]u8 align(@alignOf(elf.Elf64_Ehdr)) = undefined;
_ = try preadMin(file, &hdr_buf, 0, hdr_buf.len);
const hdr32 = @as(*elf.Elf32_Ehdr, @ptrCast(&hdr_buf));
const hdr64 = @as(*elf.Elf64_Ehdr, @ptrCast(&hdr_buf));
if (!mem.eql(u8, hdr32.e_ident[0..4], elf.MAGIC)) return error.InvalidElfMagic;
const elf_endian: std.builtin.Endian = switch (hdr32.e_ident[elf.EI_DATA]) {
elf.ELFDATA2LSB => .Little,
elf.ELFDATA2MSB => .Big,
else => return error.InvalidElfEndian,
};
const need_bswap = elf_endian != native_endian;
if (hdr32.e_ident[elf.EI_VERSION] != 1) return error.InvalidElfVersion;
const is_64 = switch (hdr32.e_ident[elf.EI_CLASS]) {
elf.ELFCLASS32 => false,
elf.ELFCLASS64 => true,
else => return error.InvalidElfClass,
};
const shstrndx = elfInt(is_64, need_bswap, hdr32.e_shstrndx, hdr64.e_shstrndx);
var shoff = elfInt(is_64, need_bswap, hdr32.e_shoff, hdr64.e_shoff);
const shentsize = elfInt(is_64, need_bswap, hdr32.e_shentsize, hdr64.e_shentsize);
const str_section_off = shoff + @as(u64, shentsize) * @as(u64, shstrndx);
var sh_buf: [16 * @sizeOf(elf.Elf64_Shdr)]u8 align(@alignOf(elf.Elf64_Shdr)) = undefined;
if (sh_buf.len < shentsize) return error.InvalidElfFile;
_ = try preadMin(file, &sh_buf, str_section_off, shentsize);
const shstr32: *elf.Elf32_Shdr = @ptrCast(@alignCast(&sh_buf));
const shstr64: *elf.Elf64_Shdr = @ptrCast(@alignCast(&sh_buf));
const shstrtab_off = elfInt(is_64, need_bswap, shstr32.sh_offset, shstr64.sh_offset);
const shstrtab_size = elfInt(is_64, need_bswap, shstr32.sh_size, shstr64.sh_size);
var strtab_buf: [4096:0]u8 = undefined;
const shstrtab_len = @min(shstrtab_size, strtab_buf.len);
const shstrtab_read_len = try preadMin(file, &strtab_buf, shstrtab_off, shstrtab_len);
const shstrtab = strtab_buf[0..shstrtab_read_len];
const shnum = elfInt(is_64, need_bswap, hdr32.e_shnum, hdr64.e_shnum);
var sh_i: u16 = 0;
const dynstr: struct { offset: u64, size: u64 } = find_dyn_str: while (sh_i < shnum) {
// Reserve some bytes so that we can deref the 64-bit struct fields
// even when the ELF file is 32-bits.
const sh_reserve: usize = @sizeOf(elf.Elf64_Shdr) - @sizeOf(elf.Elf32_Shdr);
const sh_read_byte_len = try preadMin(
file,
sh_buf[0 .. sh_buf.len - sh_reserve],
shoff,
shentsize,
);
var sh_buf_i: usize = 0;
while (sh_buf_i < sh_read_byte_len and sh_i < shnum) : ({
sh_i += 1;
shoff += shentsize;
sh_buf_i += shentsize;
}) {
const sh32: *elf.Elf32_Shdr = @ptrCast(@alignCast(&sh_buf[sh_buf_i]));
const sh64: *elf.Elf64_Shdr = @ptrCast(@alignCast(&sh_buf[sh_buf_i]));
const sh_name_off = elfInt(is_64, need_bswap, sh32.sh_name, sh64.sh_name);
const sh_name = mem.sliceTo(shstrtab[sh_name_off..], 0);
if (mem.eql(u8, sh_name, ".dynstr")) {
break :find_dyn_str .{
.offset = elfInt(is_64, need_bswap, sh32.sh_offset, sh64.sh_offset),
.size = elfInt(is_64, need_bswap, sh32.sh_size, sh64.sh_size),
};
}
}
} else return error.InvalidGnuLibCVersion;
// Here we loop over all the strings in the dynstr string table, assuming that any
// strings that start with "GLIBC_2." indicate the existence of such a glibc version,
// and furthermore, that the system-installed glibc is at minimum that version.
// Empirically, glibc 2.34 libc.so .dynstr section is 32441 bytes on my system.
// Here I use double this value plus some headroom. This makes it only need
// a single read syscall here.
var buf: [80000]u8 = undefined;
if (buf.len < dynstr.size) return error.InvalidGnuLibCVersion;
const dynstr_size = @as(usize, @intCast(dynstr.size));
const dynstr_bytes = buf[0..dynstr_size];
_ = try preadMin(file, dynstr_bytes, dynstr.offset, dynstr_bytes.len);
var it = mem.splitScalar(u8, dynstr_bytes, 0);
var max_ver: std.SemanticVersion = .{ .major = 2, .minor = 2, .patch = 5 };
while (it.next()) |s| {
if (mem.startsWith(u8, s, "GLIBC_2.")) {
const chopped = s["GLIBC_".len..];
const ver = std.SemanticVersion.parse(chopped) catch |err| switch (err) {
error.Overflow => return error.InvalidGnuLibCVersion,
error.InvalidVersion => return error.InvalidGnuLibCVersion,
};
switch (ver.order(max_ver)) {
.gt => max_ver = ver,
.lt, .eq => continue,
}
}
}
return max_ver;
}
fn glibcVerFromLinkName(link_name: []const u8, prefix: []const u8) !std.SemanticVersion {
// example: "libc-2.3.4.so"
// example: "libc-2.27.so"
// example: "ld-2.33.so"
const suffix = ".so";
if (!mem.startsWith(u8, link_name, prefix) or !mem.endsWith(u8, link_name, suffix)) {
return error.UnrecognizedGnuLibCFileName;
}
// chop off "libc-" and ".so"
const link_name_chopped = link_name[prefix.len .. link_name.len - suffix.len];
return std.SemanticVersion.parse(link_name_chopped) catch |err| switch (err) {
error.Overflow => return error.InvalidGnuLibCVersion,
error.InvalidVersion => return error.InvalidGnuLibCVersion,
};
}
pub const AbiAndDynamicLinkerFromFileError = error{
FileSystem,
SystemResources,
SymLinkLoop,
ProcessFdQuotaExceeded,
SystemFdQuotaExceeded,
UnableToReadElfFile,
InvalidElfClass,
InvalidElfVersion,
InvalidElfEndian,
InvalidElfFile,
InvalidElfMagic,
Unexpected,
UnexpectedEndOfFile,
NameTooLong,
};
pub fn abiAndDynamicLinkerFromFile(
file: fs.File,
cpu: Target.Cpu,
os: Target.Os,
ld_info_list: []const LdInfo,
cross_target: CrossTarget,
) AbiAndDynamicLinkerFromFileError!NativeTargetInfo {
var hdr_buf: [@sizeOf(elf.Elf64_Ehdr)]u8 align(@alignOf(elf.Elf64_Ehdr)) = undefined;
_ = try preadMin(file, &hdr_buf, 0, hdr_buf.len);
const hdr32 = @as(*elf.Elf32_Ehdr, @ptrCast(&hdr_buf));
const hdr64 = @as(*elf.Elf64_Ehdr, @ptrCast(&hdr_buf));
if (!mem.eql(u8, hdr32.e_ident[0..4], elf.MAGIC)) return error.InvalidElfMagic;
const elf_endian: std.builtin.Endian = switch (hdr32.e_ident[elf.EI_DATA]) {
elf.ELFDATA2LSB => .Little,
elf.ELFDATA2MSB => .Big,
else => return error.InvalidElfEndian,
};
const need_bswap = elf_endian != native_endian;
if (hdr32.e_ident[elf.EI_VERSION] != 1) return error.InvalidElfVersion;
const is_64 = switch (hdr32.e_ident[elf.EI_CLASS]) {
elf.ELFCLASS32 => false,
elf.ELFCLASS64 => true,
else => return error.InvalidElfClass,
};
var phoff = elfInt(is_64, need_bswap, hdr32.e_phoff, hdr64.e_phoff);
const phentsize = elfInt(is_64, need_bswap, hdr32.e_phentsize, hdr64.e_phentsize);
const phnum = elfInt(is_64, need_bswap, hdr32.e_phnum, hdr64.e_phnum);
var result: NativeTargetInfo = .{
.target = .{
.cpu = cpu,
.os = os,
.abi = cross_target.abi orelse Target.Abi.default(cpu.arch, os),
.ofmt = cross_target.ofmt orelse Target.ObjectFormat.default(os.tag, cpu.arch),
},
.dynamic_linker = cross_target.dynamic_linker,
};
var rpath_offset: ?u64 = null; // Found inside PT_DYNAMIC
const look_for_ld = cross_target.dynamic_linker.get() == null;
var ph_buf: [16 * @sizeOf(elf.Elf64_Phdr)]u8 align(@alignOf(elf.Elf64_Phdr)) = undefined;
if (phentsize > @sizeOf(elf.Elf64_Phdr)) return error.InvalidElfFile;
var ph_i: u16 = 0;
while (ph_i < phnum) {
// Reserve some bytes so that we can deref the 64-bit struct fields
// even when the ELF file is 32-bits.
const ph_reserve: usize = @sizeOf(elf.Elf64_Phdr) - @sizeOf(elf.Elf32_Phdr);
const ph_read_byte_len = try preadMin(file, ph_buf[0 .. ph_buf.len - ph_reserve], phoff, phentsize);
var ph_buf_i: usize = 0;
while (ph_buf_i < ph_read_byte_len and ph_i < phnum) : ({
ph_i += 1;
phoff += phentsize;
ph_buf_i += phentsize;
}) {
const ph32: *elf.Elf32_Phdr = @ptrCast(@alignCast(&ph_buf[ph_buf_i]));
const ph64: *elf.Elf64_Phdr = @ptrCast(@alignCast(&ph_buf[ph_buf_i]));
const p_type = elfInt(is_64, need_bswap, ph32.p_type, ph64.p_type);
switch (p_type) {
elf.PT_INTERP => if (look_for_ld) {
const p_offset = elfInt(is_64, need_bswap, ph32.p_offset, ph64.p_offset);
const p_filesz = elfInt(is_64, need_bswap, ph32.p_filesz, ph64.p_filesz);
if (p_filesz > result.dynamic_linker.buffer.len) return error.NameTooLong;
const filesz = @as(usize, @intCast(p_filesz));
_ = try preadMin(file, result.dynamic_linker.buffer[0..filesz], p_offset, filesz);
// PT_INTERP includes a null byte in filesz.
const len = filesz - 1;
// dynamic_linker.max_byte is "max", not "len".
// We know it will fit in u8 because we check against dynamic_linker.buffer.len above.
result.dynamic_linker.max_byte = @as(u8, @intCast(len - 1));
// Use it to determine ABI.
const full_ld_path = result.dynamic_linker.buffer[0..len];
for (ld_info_list) |ld_info| {
const standard_ld_basename = fs.path.basename(ld_info.ld.get().?);
if (std.mem.endsWith(u8, full_ld_path, standard_ld_basename)) {
result.target.abi = ld_info.abi;
break;
}
}
},
// We only need this for detecting glibc version.
elf.PT_DYNAMIC => if (builtin.target.os.tag == .linux and result.target.isGnuLibC() and
cross_target.glibc_version == null)
{
var dyn_off = elfInt(is_64, need_bswap, ph32.p_offset, ph64.p_offset);
const p_filesz = elfInt(is_64, need_bswap, ph32.p_filesz, ph64.p_filesz);
const dyn_size: usize = if (is_64) @sizeOf(elf.Elf64_Dyn) else @sizeOf(elf.Elf32_Dyn);
const dyn_num = p_filesz / dyn_size;
var dyn_buf: [16 * @sizeOf(elf.Elf64_Dyn)]u8 align(@alignOf(elf.Elf64_Dyn)) = undefined;
var dyn_i: usize = 0;
dyn: while (dyn_i < dyn_num) {
// Reserve some bytes so that we can deref the 64-bit struct fields
// even when the ELF file is 32-bits.
const dyn_reserve: usize = @sizeOf(elf.Elf64_Dyn) - @sizeOf(elf.Elf32_Dyn);
const dyn_read_byte_len = try preadMin(
file,
dyn_buf[0 .. dyn_buf.len - dyn_reserve],
dyn_off,
dyn_size,
);
var dyn_buf_i: usize = 0;
while (dyn_buf_i < dyn_read_byte_len and dyn_i < dyn_num) : ({
dyn_i += 1;
dyn_off += dyn_size;
dyn_buf_i += dyn_size;
}) {
const dyn32: *elf.Elf32_Dyn = @ptrCast(@alignCast(&dyn_buf[dyn_buf_i]));
const dyn64: *elf.Elf64_Dyn = @ptrCast(@alignCast(&dyn_buf[dyn_buf_i]));
const tag = elfInt(is_64, need_bswap, dyn32.d_tag, dyn64.d_tag);
const val = elfInt(is_64, need_bswap, dyn32.d_val, dyn64.d_val);
if (tag == elf.DT_RUNPATH) {
rpath_offset = val;
break :dyn;
}
}
}
},
else => continue,
}
}
}
if (builtin.target.os.tag == .linux and result.target.isGnuLibC() and
cross_target.glibc_version == null)
{
const shstrndx = elfInt(is_64, need_bswap, hdr32.e_shstrndx, hdr64.e_shstrndx);
var shoff = elfInt(is_64, need_bswap, hdr32.e_shoff, hdr64.e_shoff);
const shentsize = elfInt(is_64, need_bswap, hdr32.e_shentsize, hdr64.e_shentsize);
const str_section_off = shoff + @as(u64, shentsize) * @as(u64, shstrndx);
var sh_buf: [16 * @sizeOf(elf.Elf64_Shdr)]u8 align(@alignOf(elf.Elf64_Shdr)) = undefined;
if (sh_buf.len < shentsize) return error.InvalidElfFile;
_ = try preadMin(file, &sh_buf, str_section_off, shentsize);
const shstr32: *elf.Elf32_Shdr = @ptrCast(@alignCast(&sh_buf));
const shstr64: *elf.Elf64_Shdr = @ptrCast(@alignCast(&sh_buf));
const shstrtab_off = elfInt(is_64, need_bswap, shstr32.sh_offset, shstr64.sh_offset);
const shstrtab_size = elfInt(is_64, need_bswap, shstr32.sh_size, shstr64.sh_size);
var strtab_buf: [4096:0]u8 = undefined;
const shstrtab_len = @min(shstrtab_size, strtab_buf.len);
const shstrtab_read_len = try preadMin(file, &strtab_buf, shstrtab_off, shstrtab_len);
const shstrtab = strtab_buf[0..shstrtab_read_len];
const shnum = elfInt(is_64, need_bswap, hdr32.e_shnum, hdr64.e_shnum);
var sh_i: u16 = 0;
const dynstr: ?struct { offset: u64, size: u64 } = find_dyn_str: while (sh_i < shnum) {
// Reserve some bytes so that we can deref the 64-bit struct fields
// even when the ELF file is 32-bits.
const sh_reserve: usize = @sizeOf(elf.Elf64_Shdr) - @sizeOf(elf.Elf32_Shdr);
const sh_read_byte_len = try preadMin(
file,
sh_buf[0 .. sh_buf.len - sh_reserve],
shoff,
shentsize,
);
var sh_buf_i: usize = 0;
while (sh_buf_i < sh_read_byte_len and sh_i < shnum) : ({
sh_i += 1;
shoff += shentsize;
sh_buf_i += shentsize;
}) {
const sh32: *elf.Elf32_Shdr = @ptrCast(@alignCast(&sh_buf[sh_buf_i]));
const sh64: *elf.Elf64_Shdr = @ptrCast(@alignCast(&sh_buf[sh_buf_i]));
const sh_name_off = elfInt(is_64, need_bswap, sh32.sh_name, sh64.sh_name);
const sh_name = mem.sliceTo(shstrtab[sh_name_off..], 0);
if (mem.eql(u8, sh_name, ".dynstr")) {
break :find_dyn_str .{
.offset = elfInt(is_64, need_bswap, sh32.sh_offset, sh64.sh_offset),
.size = elfInt(is_64, need_bswap, sh32.sh_size, sh64.sh_size),
};
}
}
} else null;
if (dynstr) |ds| {
if (rpath_offset) |rpoff| {
// TODO this pointer cast should not be necessary
const rpoff_usize = std.math.cast(usize, rpoff) orelse return error.InvalidElfFile;
if (rpoff_usize > ds.size) return error.InvalidElfFile;
const rpoff_file = ds.offset + rpoff_usize;
const rp_max_size = ds.size - rpoff_usize;
const strtab_len = @min(rp_max_size, strtab_buf.len);
const strtab_read_len = try preadMin(file, &strtab_buf, rpoff_file, strtab_len);
const strtab = strtab_buf[0..strtab_read_len];
const rpath_list = mem.sliceTo(strtab, 0);
var it = mem.tokenizeScalar(u8, rpath_list, ':');
while (it.next()) |rpath| {
if (glibcVerFromRPath(rpath)) |ver| {
result.target.os.version_range.linux.glibc = ver;
return result;
} else |err| switch (err) {
error.GLibCNotFound => continue,
else => |e| return e,
}
}
}
}
if (result.dynamic_linker.get()) |dl_path| glibc_ver: {
// There is no DT_RUNPATH so we try to find libc.so.6 inside the same
// directory as the dynamic linker.
if (fs.path.dirname(dl_path)) |rpath| {
if (glibcVerFromRPath(rpath)) |ver| {
result.target.os.version_range.linux.glibc = ver;
return result;
} else |err| switch (err) {
error.GLibCNotFound => {},
else => |e| return e,
}
}
// So far, no luck. Next we try to see if the information is
// present in the symlink data for the dynamic linker path.
var link_buf: [std.os.PATH_MAX]u8 = undefined;
const link_name = std.os.readlink(dl_path, &link_buf) catch |err| switch (err) {
error.NameTooLong => unreachable,
error.InvalidUtf8 => unreachable, // Windows only
error.BadPathName => unreachable, // Windows only
error.UnsupportedReparsePointType => unreachable, // Windows only
error.NetworkNotFound => unreachable, // Windows only
error.AccessDenied,
error.FileNotFound,
error.NotLink,
error.NotDir,
=> break :glibc_ver,
error.SystemResources,
error.FileSystem,
error.SymLinkLoop,
error.Unexpected,
=> |e| return e,
};
result.target.os.version_range.linux.glibc = glibcVerFromLinkName(
fs.path.basename(link_name),
"ld-",
) catch |err| switch (err) {
error.UnrecognizedGnuLibCFileName,
error.InvalidGnuLibCVersion,
=> break :glibc_ver,
};
return result;
}
// Nothing worked so far. Finally we fall back to hard-coded search paths.
// Some distros such as Debian keep their libc.so.6 in `/lib/$triple/`.
var path_buf: [std.os.PATH_MAX]u8 = undefined;
var index: usize = 0;
const prefix = "/lib/";
const cpu_arch = @tagName(result.target.cpu.arch);
const os_tag = @tagName(result.target.os.tag);
const abi = @tagName(result.target.abi);
@memcpy(path_buf[index..][0..prefix.len], prefix);
index += prefix.len;
@memcpy(path_buf[index..][0..cpu_arch.len], cpu_arch);
index += cpu_arch.len;
path_buf[index] = '-';
index += 1;
@memcpy(path_buf[index..][0..os_tag.len], os_tag);
index += os_tag.len;
path_buf[index] = '-';
index += 1;
@memcpy(path_buf[index..][0..abi.len], abi);
index += abi.len;
const rpath = path_buf[0..index];
if (glibcVerFromRPath(rpath)) |ver| {
result.target.os.version_range.linux.glibc = ver;
return result;
} else |err| switch (err) {
error.GLibCNotFound => {},
else => |e| return e,
}
}
return result;
}
fn preadMin(file: fs.File, buf: []u8, offset: u64, min_read_len: usize) !usize {
var i: usize = 0;
while (i < min_read_len) {
const len = file.pread(buf[i..], offset + i) catch |err| switch (err) {
error.OperationAborted => unreachable, // Windows-only
error.WouldBlock => unreachable, // Did not request blocking mode
error.NotOpenForReading => unreachable,
error.SystemResources => return error.SystemResources,
error.IsDir => return error.UnableToReadElfFile,
error.BrokenPipe => return error.UnableToReadElfFile,
error.Unseekable => return error.UnableToReadElfFile,
error.ConnectionResetByPeer => return error.UnableToReadElfFile,
error.ConnectionTimedOut => return error.UnableToReadElfFile,
error.NetNameDeleted => return error.UnableToReadElfFile,
error.Unexpected => return error.Unexpected,
error.InputOutput => return error.FileSystem,
error.AccessDenied => return error.Unexpected,
};
if (len == 0) return error.UnexpectedEndOfFile;
i += len;
}
return i;
}
fn defaultAbiAndDynamicLinker(cpu: Target.Cpu, os: Target.Os, cross_target: CrossTarget) !NativeTargetInfo {
const target: Target = .{
.cpu = cpu,
.os = os,
.abi = cross_target.abi orelse Target.Abi.default(cpu.arch, os),
.ofmt = cross_target.ofmt orelse Target.ObjectFormat.default(os.tag, cpu.arch),
};
return NativeTargetInfo{
.target = target,
.dynamic_linker = if (cross_target.dynamic_linker.get() == null)
target.standardDynamicLinkerPath()
else
cross_target.dynamic_linker,
};
}
pub const LdInfo = struct {
ld: DynamicLinker,
abi: Target.Abi,
};
pub fn elfInt(is_64: bool, need_bswap: bool, int_32: anytype, int_64: anytype) @TypeOf(int_64) {
if (is_64) {
if (need_bswap) {
return @byteSwap(int_64);
} else {
return int_64;
}
} else {
if (need_bswap) {
return @byteSwap(int_32);
} else {
return int_32;
}
}
}
fn detectNativeCpuAndFeatures(cpu_arch: Target.Cpu.Arch, os: Target.Os, cross_target: CrossTarget) ?Target.Cpu {
// Here we switch on a comptime value rather than `cpu_arch`. This is valid because `cpu_arch`,
// although it is a runtime value, is guaranteed to be one of the architectures in the set
// of the respective switch prong.
switch (builtin.cpu.arch) {
.x86_64, .x86 => {
return @import("x86.zig").detectNativeCpuAndFeatures(cpu_arch, os, cross_target);
},
else => {},
}
switch (builtin.os.tag) {
.linux => return linux.detectNativeCpuAndFeatures(),
.macos => return darwin.macos.detectNativeCpuAndFeatures(),
.windows => return windows.detectNativeCpuAndFeatures(),
else => {},
}
// This architecture does not have CPU model & feature detection yet.
// See https://github.com/ziglang/zig/issues/4591
return null;
}
pub const Executor = union(enum) {
native,
rosetta,
qemu: []const u8,
wine: []const u8,
wasmtime: []const u8,
darling: []const u8,
bad_dl: []const u8,
bad_os_or_cpu,
};
pub const GetExternalExecutorOptions = struct {
allow_darling: bool = true,
allow_qemu: bool = true,
allow_rosetta: bool = true,
allow_wasmtime: bool = true,
allow_wine: bool = true,
qemu_fixes_dl: bool = false,
link_libc: bool = false,
};
/// Return whether or not the given host target is capable of executing natively executables
/// of the other target.
pub fn getExternalExecutor(
host: NativeTargetInfo,
candidate: NativeTargetInfo,
options: GetExternalExecutorOptions,
) Executor {
const os_match = host.target.os.tag == candidate.target.os.tag;
const cpu_ok = cpu_ok: {
if (host.target.cpu.arch == candidate.target.cpu.arch)
break :cpu_ok true;
if (host.target.cpu.arch == .x86_64 and candidate.target.cpu.arch == .x86)
break :cpu_ok true;
if (host.target.cpu.arch == .aarch64 and candidate.target.cpu.arch == .arm)
break :cpu_ok true;
if (host.target.cpu.arch == .aarch64_be and candidate.target.cpu.arch == .armeb)
break :cpu_ok true;
// TODO additionally detect incompatible CPU features.
// Note that in some cases the OS kernel will emulate missing CPU features
// when an illegal instruction is encountered.
break :cpu_ok false;
};
var bad_result: Executor = .bad_os_or_cpu;
if (os_match and cpu_ok) native: {
if (options.link_libc) {
if (candidate.dynamic_linker.get()) |candidate_dl| {
fs.cwd().access(candidate_dl, .{}) catch {
bad_result = .{ .bad_dl = candidate_dl };
break :native;
};
}
}
return .native;
}
// If the OS match and OS is macOS and CPU is arm64, we can use Rosetta 2
// to emulate the foreign architecture.
if (options.allow_rosetta and os_match and
host.target.os.tag == .macos and host.target.cpu.arch == .aarch64)
{
switch (candidate.target.cpu.arch) {
.x86_64 => return .rosetta,
else => return bad_result,
}
}
// If the OS matches, we can use QEMU to emulate a foreign architecture.
if (options.allow_qemu and os_match and (!cpu_ok or options.qemu_fixes_dl)) {
return switch (candidate.target.cpu.arch) {
.aarch64 => Executor{ .qemu = "qemu-aarch64" },
.aarch64_be => Executor{ .qemu = "qemu-aarch64_be" },
.arm => Executor{ .qemu = "qemu-arm" },
.armeb => Executor{ .qemu = "qemu-armeb" },
.hexagon => Executor{ .qemu = "qemu-hexagon" },
.x86 => Executor{ .qemu = "qemu-i386" },
.m68k => Executor{ .qemu = "qemu-m68k" },
.mips => Executor{ .qemu = "qemu-mips" },
.mipsel => Executor{ .qemu = "qemu-mipsel" },
.mips64 => Executor{ .qemu = "qemu-mips64" },
.mips64el => Executor{ .qemu = "qemu-mips64el" },
.powerpc => Executor{ .qemu = "qemu-ppc" },
.powerpc64 => Executor{ .qemu = "qemu-ppc64" },
.powerpc64le => Executor{ .qemu = "qemu-ppc64le" },
.riscv32 => Executor{ .qemu = "qemu-riscv32" },
.riscv64 => Executor{ .qemu = "qemu-riscv64" },
.s390x => Executor{ .qemu = "qemu-s390x" },
.sparc => Executor{ .qemu = "qemu-sparc" },
.sparc64 => Executor{ .qemu = "qemu-sparc64" },
.x86_64 => Executor{ .qemu = "qemu-x86_64" },
else => return bad_result,
};
}
switch (candidate.target.os.tag) {
.windows => {
if (options.allow_wine) {
// x86_64 wine does not support emulating aarch64-windows and
// vice versa.
if (candidate.target.cpu.arch != builtin.cpu.arch) {
return bad_result;
}
switch (candidate.target.ptrBitWidth()) {
32 => return Executor{ .wine = "wine" },
64 => return Executor{ .wine = "wine64" },
else => return bad_result,
}
}
return bad_result;
},
.wasi => {
if (options.allow_wasmtime) {
switch (candidate.target.ptrBitWidth()) {
32 => return Executor{ .wasmtime = "wasmtime" },
else => return bad_result,
}
}
return bad_result;
},
.macos => {
if (options.allow_darling) {
// This check can be loosened once darling adds a QEMU-based emulation
// layer for non-host architectures:
// https://github.com/darlinghq/darling/issues/863
if (candidate.target.cpu.arch != builtin.cpu.arch) {
return bad_result;
}
return Executor{ .darling = "darling" };
}
return bad_result;
},
else => return bad_result,
}
}
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