make tests ignore root more robustly (#42533)

(cherry picked from commit 536d35e)

base/libc.jl

@@ -404,36 +404,36 @@ srand(seed=floor(Int, time()) % Cuint) = ccall(:srand, Cvoid, (Cuint,), seed)
 
 struct Cpasswd
    username::Cstring
-   uid::Clong
-   gid::Clong
+   uid::Culong
+   gid::Culong
    shell::Cstring
    homedir::Cstring
    gecos::Cstring
-   Cpasswd() = new(C_NULL, -1, -1, C_NULL, C_NULL, C_NULL)
+   Cpasswd() = new(C_NULL, typemax(Culong), typemax(Culong), C_NULL, C_NULL, C_NULL)
 end
 mutable struct Cgroup
-    groupname::Cstring     # group name
-    gid::Clong        # group ID
-    mem::Ptr{Cstring} # group members
-    Cgroup() = new(C_NULL, -1, C_NULL)
+    groupname::Cstring # group name
+    gid::Culong        # group ID
+    mem::Ptr{Cstring}  # group members
+    Cgroup() = new(C_NULL, typemax(Culong), C_NULL)
 end
 struct Passwd
     username::String
-    uid::Int
-    gid::Int
+    uid::UInt
+    gid::UInt
     shell::String
     homedir::String
     gecos::String
 end
 struct Group
     groupname::String
-    gid::Int
+    gid::UInt
     mem::Vector{String}
 end
 
 function getpwuid(uid::Unsigned, throw_error::Bool=true)
     ref_pd = Ref(Cpasswd())
-    ret = ccall(:jl_os_get_passwd, Cint, (Ref{Cpasswd}, UInt), ref_pd, uid)
+    ret = ccall(:jl_os_get_passwd, Cint, (Ref{Cpasswd}, Culong), ref_pd, uid)
     if ret != 0
         throw_error && Base.uv_error("getpwuid", ret)
         return
@@ -452,7 +452,7 @@ function getpwuid(uid::Unsigned, throw_error::Bool=true)
 end
 function getgrgid(gid::Unsigned, throw_error::Bool=true)
     ref_gp = Ref(Cgroup())
-    ret = ccall(:jl_os_get_group, Cint, (Ref{Cgroup}, UInt), ref_gp, gid)
+    ret = ccall(:jl_os_get_group, Cint, (Ref{Cgroup}, Culong), ref_gp, gid)
     if ret != 0
         throw_error && Base.uv_error("getgrgid", ret)
         return
@@ -475,6 +475,9 @@ function getgrgid(gid::Unsigned, throw_error::Bool=true)
     return gp
 end
 
+getuid() = ccall(:jl_getuid, Culong, ())
+geteuid() = ccall(:jl_geteuid, Culong, ())
+
 # Include dlopen()/dlpath() code
 include("libdl.jl")
 using .Libdl

src/sys.c

@@ -232,7 +232,25 @@ JL_DLLEXPORT double jl_stat_ctime(char *statbuf)
     return (double)s->st_ctim.tv_sec + (double)s->st_ctim.tv_nsec * 1e-9;
 }
 
-JL_DLLEXPORT int jl_os_get_passwd(uv_passwd_t *pwd, size_t uid)
+JL_DLLEXPORT unsigned long jl_getuid(void)
+{
+#ifdef _OS_WINDOWS_
+    return -1;
+#else
+    return getuid();
+#endif
+}
+
+JL_DLLEXPORT unsigned long jl_geteuid(void)
+{
+#ifdef _OS_WINDOWS_
+    return -1;
+#else
+    return geteuid();
+#endif
+}
+
+JL_DLLEXPORT int jl_os_get_passwd(uv_passwd_t *pwd, unsigned long uid)
 {
 #ifdef _OS_WINDOWS_
   return UV_ENOTSUP;
@@ -345,11 +363,11 @@ JL_DLLEXPORT int jl_os_get_passwd(uv_passwd_t *pwd, size_t uid)
 
 typedef struct jl_group_s {
     char* groupname;
-    long gid;
+    unsigned long gid;
     char** members;
 } jl_group_t;
 
-JL_DLLEXPORT int jl_os_get_group(jl_group_t *grp, size_t gid)
+JL_DLLEXPORT int jl_os_get_group(jl_group_t *grp, unsigned long gid)
 {
 #ifdef _OS_WINDOWS_
   return UV_ENOTSUP;

test/file.jl

@@ -516,7 +516,10 @@ end
 
 if !Sys.iswindows()
     # chown will give an error if the user does not have permissions to change files
-    if get(ENV, "USER", "") == "root" || get(ENV, "HOME", "") == "/root"
+    uid = Libc.geteuid()
+    @test stat(file).uid == uid
+    @test uid == Libc.getuid()
+    if uid == 0 # root user
         chown(file, -2, -1)  # Change the file owner to nobody
         @test stat(file).uid != 0
         chown(file, 0, -2)  # Change the file group to nogroup (and owner back to root)

test/read.jl

@@ -461,7 +461,7 @@ rm(f)
 io = Base.Filesystem.open(f, Base.Filesystem.JL_O_WRONLY | Base.Filesystem.JL_O_CREAT | Base.Filesystem.JL_O_EXCL, 0o000)
 @test write(io, "abc") == 3
 close(io)
-if !Sys.iswindows() && get(ENV, "USER", "") != "root" && get(ENV, "HOME", "") != "/root"
+if !Sys.iswindows() && Libc.geteuid() != 0 # root user
     # msvcrt _wchmod documentation states that all files are readable,
     # so we don't test that it correctly set the umask on windows
     @test_throws SystemError open(f)
@@ -511,7 +511,7 @@ close(f1)
 close(f2)
 @test eof(f1)
 @test_throws Base.IOError eof(f2)
-if get(ENV, "USER", "") != "root" && get(ENV, "HOME", "") != "/root"
+if Libc.geteuid() != 0 # root user
     @test_throws SystemError open(f, "r+")
     @test_throws Base.IOError Base.Filesystem.open(f, Base.Filesystem.JL_O_RDWR)
 else