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Truncate user and group ids for 64 bit Linux systems (#7466)

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* Truncate user and group ids

Calls to `getuid`, `getgid` and their `eid` variants fail to compile on
64bit Linux systems because the return value of the syscall is of
`usize` and needs to be truncated to fit the size of `uid_t` that is 32
bit.

Thanks to @FireFox317 for figuring this out in Zig's Discord channel!

* Add a regression test for user and group ids

* Replace @truncate with @intCast

This should be safe because `uid_t` will be 32-bit.

* Add missing import for getauxval

* Add missing package names

* Revert "Add missing import for getauxval"

This reverts commit 38f93dc89effdf657f2b81a56b96527ce4083f52.

* Skip user and group test if builtin.link_libc
This commit is contained in:
Andreas Linz
2020-12-23 10:16:27 +01:00
committed by GitHub
parent 4420dabdf5
commit 7e63f7ad03
2 changed files with 17 additions and 8 deletions
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16
lib/std/os/linux.zig
View File

@@ -745,33 +745,33 @@ pub fn setregid(rgid: gid_t, egid: gid_t) usize {
pub fn getuid() uid_t {
if (@hasField(SYS, "getuid32")) {
return @as(uid_t, syscall0(.getuid32));
return @intCast(uid_t, syscall0(.getuid32));
} else {
return @as(uid_t, syscall0(.getuid));
return @intCast(uid_t, syscall0(.getuid));
}
}
pub fn getgid() gid_t {
if (@hasField(SYS, "getgid32")) {
return @as(gid_t, syscall0(.getgid32));
return @intCast(gid_t, syscall0(.getgid32));
} else {
return @as(gid_t, syscall0(.getgid));
return @intCast(gid_t, syscall0(.getgid));
}
}
pub fn geteuid() uid_t {
if (@hasField(SYS, "geteuid32")) {
return @as(uid_t, syscall0(.geteuid32));
return @intCast(uid_t, syscall0(.geteuid32));
} else {
return @as(uid_t, syscall0(.geteuid));
return @intCast(uid_t, syscall0(.geteuid));
}
}
pub fn getegid() gid_t {
if (@hasField(SYS, "getegid32")) {
return @as(gid_t, syscall0(.getegid32));
return @intCast(gid_t, syscall0(.getegid32));
} else {
return @as(gid_t, syscall0(.getegid));
return @intCast(gid_t, syscall0(.getegid));
}
}

9
lib/std/os/linux/test.zig
View File

@@ -9,6 +9,7 @@ const linux = std.os.linux;
const mem = std.mem;
const elf = std.elf;
const expect = std.testing.expect;
const expectEqual = std.testing.expectEqual;
const fs = std.fs;
test "fallocate" {
@@ -99,3 +100,11 @@ test "statx" {
expect(@bitCast(u64, @as(i64, stat_buf.blksize)) == statx_buf.blksize);
expect(@bitCast(u64, @as(i64, stat_buf.blocks)) == statx_buf.blocks);
}
test "user and group ids" {
if (builtin.link_libc) return error.SkipZigTest;
expectEqual(linux.getauxval(elf.AT_UID), linux.getuid());
expectEqual(linux.getauxval(elf.AT_GID), linux.getgid());
expectEqual(linux.getauxval(elf.AT_EUID), linux.geteuid());
expectEqual(linux.getauxval(elf.AT_EGID), linux.getegid());
}