Replace the libc environment with a thread-safe emulation

putenv(3) and friends aren't thread-safe regardless of how you slice
it; a global lock around all environment operations (like before)
keeps things safe as far as our own operations go, but we have
absolutely no control over what libc or a library dragged in by a
driver/NIF does -- they're free to call getenv(3) or putenv(3)
without honoring our lock.

This commit solves this by setting up an "emulated" environment which
can't be touched without going through our interfaces. Third-party
libraries can still shoot themselves in the foot but benign uses of
os:putenv/2 will no longer risk crashing the emulator.

13 files changed, 184 insertions, 347 deletions

diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 1bd4acbf95..1c5e19cd88 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -374,9 +374,10 @@ bif ets:match_spec_run_r/3
 # Bifs in os module.
 #
 
-bif os:putenv/2
-bif os:getenv/0
-bif os:getenv/1
+bif os:get_env_var/1
+bif os:set_env_var/2
+bif os:unset_env_var/1
+bif os:list_env_vars/0
 bif os:getpid/0
 bif os:timestamp/0
 bif os:system_time/0
@@ -617,7 +618,6 @@ bif erlang:float_to_binary/2
 bif erlang:binary_to_float/1
 
 bif io:printable_range/0
-bif os:unsetenv/1
 
 #
 # New in 17.0
diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index 2bfb481771..cb8812c455 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -775,16 +775,16 @@ erl_crash_dump_v(char *file, int line, char* fmt, va_list args)
      * - write dump until alarm or file is written completely
      */
 	
-    if (erts_sys_getenv__("ERL_CRASH_DUMP_SECONDS", env, &envsz) != 0) {
-	env_erl_crash_dump_seconds_set = 0;
-	secs = -1;
+    if (erts_sys_explicit_8bit_getenv("ERL_CRASH_DUMP_SECONDS", env, &envsz) == 1) {
+        env_erl_crash_dump_seconds_set = 1;
+        secs = atoi(env);
     } else {
-	env_erl_crash_dump_seconds_set = 1;
-	secs = atoi(env);
+        env_erl_crash_dump_seconds_set = 0;
+        secs = -1;
     }
 
     if (secs == 0) {
-	return;
+        return;
     }
 
     /* erts_sys_prepare_crash_dump returns 1 if heart port is found, otherwise 0
@@ -800,7 +800,7 @@ erl_crash_dump_v(char *file, int line, char* fmt, va_list args)
 
     crash_dump_limit = ERTS_SINT64_MAX;
     envsz = sizeof(env);
-    if (erts_sys_getenv__("ERL_CRASH_DUMP_BYTES", env, &envsz) == 0) {
+    if (erts_sys_explicit_8bit_getenv("ERL_CRASH_DUMP_BYTES", env, &envsz) == 1) {
         Sint64 limit;
         char* endptr;
         errno = 0;
@@ -813,7 +813,7 @@ erl_crash_dump_v(char *file, int line, char* fmt, va_list args)
         }
     }
 
-    if (erts_sys_getenv__("ERL_CRASH_DUMP",&dumpnamebuf[0],&dumpnamebufsize) != 0)
+    if (erts_sys_explicit_8bit_getenv("ERL_CRASH_DUMP",&dumpnamebuf[0],&dumpnamebufsize) != 1)
 	dumpname = "erl_crash.dump";
     else
 	dumpname = &dumpnamebuf[0];
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index 7ff7462bf6..30390cdb5e 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -1212,7 +1212,7 @@ erts_dsig_send_group_leader(ErtsDSigData *dsdp, Eterm leader, Eterm remote)
 #  define PURIFY_MSG(msg)                                                    \
     do {								     \
 	char buf__[1]; size_t bufsz__ = sizeof(buf__);			     \
-	if (erts_sys_getenv_raw("VALGRIND_LOG_XML", buf__, &bufsz__) >= 0) { \
+	if (erts_sys_explicit_8bit_getenv("VALGRIND_LOG_XML", buf__, &bufsz__) >= 0) { \
 	    VALGRIND_PRINTF_XML("<erlang_error_log>"			     \
 			    "%s, line %d: %s</erlang_error_log>\n",	     \
 			    __FILE__, __LINE__, msg);			     \
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index c6cc5c78b3..8107f133aa 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -283,6 +283,8 @@ type	THR_PRGR_DATA	LONG_LIVED	SYSTEM		thr_prgr_data
 type	T_THR_PRGR_DATA	SHORT_LIVED	SYSTEM		temp_thr_prgr_data
 type	RELEASE_LAREA	SHORT_LIVED	SYSTEM		release_literal_area
 
+type	ENVIRONMENT	SYSTEM		SYSTEM		environment
+
 #
 # Types used for special emulators
 #
@@ -370,8 +372,6 @@ type	SYS_READ_BUF	TEMPORARY	SYSTEM		sys_read_buf
 type	FD_TAB		LONG_LIVED	SYSTEM		fd_tab
 type	FD_ENTRY_BUF	STANDARD	SYSTEM		fd_entry_buf
 type	CS_PROG_PATH	LONG_LIVED	SYSTEM		cs_prog_path
-type	ENVIRONMENT	TEMPORARY	SYSTEM		environment
-type	PUTENV_STR	SYSTEM		SYSTEM		putenv_string
 type	PRT_REP_EXIT	STANDARD	SYSTEM		port_report_exit
 type	SYS_BLOCKING	STANDARD	SYSTEM		sys_blocking
 
@@ -383,9 +383,7 @@ type	SYS_WRITE_BUF	TEMPORARY	SYSTEM		sys_write_buf
 
 type	DRV_DATA_BUF	SYSTEM		SYSTEM		drv_data_buf
 type	PRELOADED	LONG_LIVED	SYSTEM		preloaded
-type	PUTENV_STR	SYSTEM		SYSTEM		putenv_string
 type	WAITER_OBJ	LONG_LIVED	SYSTEM		waiter_object
-type	ENVIRONMENT	SYSTEM		SYSTEM		environment
 type	CON_VPRINTF_BUF	TEMPORARY	SYSTEM		con_vprintf_buf
 
 +endif
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 64639e157b..9aafab86c0 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -1754,7 +1754,7 @@ static int check_if_xml(void)
 {
     char buf[1];
     size_t bufsz = sizeof(buf);
-    return erts_sys_getenv_raw("VALGRIND_LOG_XML", buf, &bufsz) >= 0;
+    return erts_sys_explicit_8bit_getenv("VALGRIND_LOG_XML", buf, &bufsz) >= 0;
 }
 #else
 #define check_if_xml() 0
diff --git a/erts/emulator/beam/erl_bif_os.c b/erts/emulator/beam/erl_bif_os.c
index 910325a2f4..ce2b27409b 100644
--- a/erts/emulator/beam/erl_bif_os.c
+++ b/erts/emulator/beam/erl_bif_os.c
@@ -36,8 +36,7 @@
 #include "big.h"
 #include "dist.h"
 #include "erl_version.h"
-
-static int check_env_name(char *name);
+#include "erl_osenv.h"
 
 /*
  * Return the pid for the Erlang process in the host OS.
@@ -67,148 +66,78 @@ BIF_RETTYPE os_getpid_0(BIF_ALIST_0)
      BIF_RET(buf_to_intlist(&hp, pid_string, n, NIL));
 }
 
-BIF_RETTYPE os_getenv_0(BIF_ALIST_0)
+static void os_getenv_foreach(Process *process, Eterm *result, Eterm key, Eterm value)
 {
-    GETENV_STATE state;
-    char *cp;
-    Eterm* hp;
-    Eterm ret;
-    Eterm str;
+    Eterm kvp_term, *hp;
 
-    init_getenv_state(&state);
+    hp = HAlloc(process, 5);
+    kvp_term = TUPLE2(hp, key, value);
+    hp += 3;
 
-    ret = NIL;
-    while ((cp = getenv_string(&state)) != NULL) {
-	str = erts_convert_native_to_filename(BIF_P,(byte *)cp);
-	hp = HAlloc(BIF_P, 2);
-	ret = CONS(hp, str, ret);
-    }
+    (*result) = CONS(hp, kvp_term, (*result));
+}
 
-    fini_getenv_state(&state);
+BIF_RETTYPE os_list_env_vars_0(BIF_ALIST_0)
+{
+    const erts_osenv_t *global_env;
+    Eterm result = NIL;
+
+    global_env = erts_sys_rlock_global_osenv();
+    erts_osenv_foreach_term(global_env, BIF_P, &result, (void*)&os_getenv_foreach);
+    erts_sys_runlock_global_osenv();
 
-    return ret;
+    return result;
 }
 
-#define STATIC_BUF_SIZE 1024
-BIF_RETTYPE os_getenv_1(BIF_ALIST_1)
+BIF_RETTYPE os_get_env_var_1(BIF_ALIST_1)
 {
-    Process* p = BIF_P;
-    Eterm str;
-    Sint len;
-    int res;
-    char *key_str, *val;
-    char buf[STATIC_BUF_SIZE];
-    size_t val_size = sizeof(buf);
-
-    key_str = erts_convert_filename_to_native(BIF_ARG_1,buf,STATIC_BUF_SIZE,
-					      ERTS_ALC_T_TMP,1,0,&len);
-
-    if (!check_env_name(key_str)) {
-        if (key_str && key_str != &buf[0])
-            erts_free(ERTS_ALC_T_TMP, key_str);
-        BIF_ERROR(p, BADARG);
-    }
+    const erts_osenv_t *global_env;
+    Eterm out_term;
+    int error;
 
-    if (key_str != &buf[0])
-	val = &buf[0];
-    else {
-	/* len includes zero byte */
-	val_size -= len;
-	val = &buf[len];
-    }
-    res = erts_sys_getenv(key_str, val, &val_size);
-
-    if (res < 0) {
-    no_var:
-	str = am_false;
-    } else {
-	if (res > 0) {
-	    val = erts_alloc(ERTS_ALC_T_TMP, val_size);
-	    while (1) {
-		res = erts_sys_getenv(key_str, val, &val_size);
-		if (res == 0)
-		    break;
-		else if (res < 0)
-		    goto no_var;
-		else
-		    val = erts_realloc(ERTS_ALC_T_TMP, val, val_size);
-	    }
-	}
-	str = erts_convert_native_to_filename(p,(byte *)val);
-    }
-    if (key_str != &buf[0])
-	erts_free(ERTS_ALC_T_TMP, key_str);
-    if (val < &buf[0] || &buf[sizeof(buf)-1] < val)
-	erts_free(ERTS_ALC_T_TMP, val);
-    BIF_RET(str);
+    global_env = erts_sys_rlock_global_osenv();
+    error = erts_osenv_get_term(global_env, BIF_P, BIF_ARG_1, &out_term);
+    erts_sys_runlock_global_osenv();
+
+    if (error == 0) {
+        return am_false;
+    } else if (error < 0) {
+        BIF_ERROR(BIF_P, BADARG);
+    } 
+
+    return out_term;
 }
 
-BIF_RETTYPE os_putenv_2(BIF_ALIST_2)
+BIF_RETTYPE os_set_env_var_2(BIF_ALIST_2)
 {
-    char def_buf_key[STATIC_BUF_SIZE];
-    char def_buf_value[STATIC_BUF_SIZE];
-    char *key_buf = NULL, *value_buf = NULL;
-
-    key_buf = erts_convert_filename_to_native(BIF_ARG_1,def_buf_key,
-					      STATIC_BUF_SIZE,
-					      ERTS_ALC_T_TMP,0,0,NULL);
-    if (!check_env_name(key_buf))
-        goto badarg;
-
-    value_buf = erts_convert_filename_to_native(BIF_ARG_2,def_buf_value,
-						STATIC_BUF_SIZE,
-						ERTS_ALC_T_TMP,1,0,
-						NULL);
-    if (!value_buf)
-        goto badarg;
-
-    if (erts_sys_putenv(key_buf, value_buf)) {
-	if (key_buf != def_buf_key) {
-	    erts_free(ERTS_ALC_T_TMP, key_buf);
-	}
-	if (value_buf != def_buf_value) {
-	    erts_free(ERTS_ALC_T_TMP, value_buf);
-	}
-	BIF_ERROR(BIF_P, BADARG);
-    }
-    if (key_buf != def_buf_key) {
-	erts_free(ERTS_ALC_T_TMP, key_buf);
-    }
-    if (value_buf != def_buf_value) {
-	erts_free(ERTS_ALC_T_TMP, value_buf);
+    erts_osenv_t *global_env;
+    int error;
+
+    global_env = erts_sys_rwlock_global_osenv();
+    error = erts_osenv_put_term(global_env, BIF_ARG_1, BIF_ARG_2);
+    erts_sys_rwunlock_global_osenv();
+
+    if (error < 0) {
+        BIF_ERROR(BIF_P, BADARG);
     }
-    BIF_RET(am_true);
 
-badarg:
-    if (key_buf && key_buf != def_buf_key)
-	erts_free(ERTS_ALC_T_TMP, key_buf);
-    if (value_buf && value_buf != def_buf_value)
-	erts_free(ERTS_ALC_T_TMP, value_buf);
-    BIF_ERROR(BIF_P, BADARG);
+    BIF_RET(am_true);
 }
 
-BIF_RETTYPE os_unsetenv_1(BIF_ALIST_1)
+BIF_RETTYPE os_unset_env_var_1(BIF_ALIST_1)
 {
-    char *key_buf;
-    char buf[STATIC_BUF_SIZE];
+    erts_osenv_t *global_env;
+    int error;
 
-    key_buf = erts_convert_filename_to_native(BIF_ARG_1,buf,STATIC_BUF_SIZE,
-					      ERTS_ALC_T_TMP,0,0,NULL);
-    if (!check_env_name(key_buf))
-        goto badarg;
+    global_env = erts_sys_rwlock_global_osenv();
+    error = erts_osenv_unset_term(global_env, BIF_ARG_1);
+    erts_sys_rwunlock_global_osenv();
 
-    if (erts_sys_unsetenv(key_buf))
-        goto badarg;
-
-    if (key_buf != buf) {
-	erts_free(ERTS_ALC_T_TMP, key_buf);
+    if (error < 0) {
+        BIF_ERROR(BIF_P, BADARG);
     }
-    BIF_RET(am_true);
 
-badarg:
-    if (key_buf && key_buf != buf)
-        erts_free(ERTS_ALC_T_TMP, key_buf);
-    BIF_ERROR(BIF_P, BADARG);    
+    BIF_RET(am_true);
 }
 
 BIF_RETTYPE os_set_signal_2(BIF_ALIST_2) {
@@ -224,27 +153,3 @@ BIF_RETTYPE os_set_signal_2(BIF_ALIST_2) {
 error:
     BIF_ERROR(BIF_P, BADARG);
 }
-
-static int
-check_env_name(char *raw_name)
-{
-    byte *c = (byte *) raw_name;
-    int encoding;
-
-    if (!c)
-        return 0;
-    
-    encoding = erts_get_native_filename_encoding();
-
-    if (erts_raw_env_char_is_7bit_ascii_char('\0', c, encoding))
-        return 0; /* Do not allow empty name... */
-
-    /* Verify no '=' characters in variable name... */
-    do {
-        if (erts_raw_env_char_is_7bit_ascii_char('=', c, encoding))
-            return 0;
-        c = erts_raw_env_next_char(c, encoding);
-    } while (!erts_raw_env_char_is_7bit_ascii_char('\0', c, encoding));
-
-    return 1; /* Seems ok... */
-}
diff --git a/erts/emulator/beam/erl_bif_port.c b/erts/emulator/beam/erl_bif_port.c
index c4a4dd5863..9f0c90ff7b 100644
--- a/erts/emulator/beam/erl_bif_port.c
+++ b/erts/emulator/beam/erl_bif_port.c
@@ -45,7 +45,7 @@
 #include "dtrace-wrapper.h"
 
 static Port *open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump);
-static char* convert_environment(Eterm env);
+static int merge_global_environment(erts_osenv_t *env, Eterm key_value_pairs);
 static char **convert_args(Eterm);
 static void free_args(char **);
 
@@ -651,6 +651,7 @@ BIF_RETTYPE port_get_data_1(BIF_ALIST_1)
 static Port *
 open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump)
 {
+    int merged_environment = 0;
     Sint i;
     Eterm option;
     Uint arity;
@@ -672,12 +673,13 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump)
     opts.read_write = 0;
     opts.hide_window = 0;
     opts.wd = NULL;
-    opts.envir = NULL;
     opts.exit_status = 0;
     opts.overlapped_io = 0; 
     opts.spawn_type = ERTS_SPAWN_ANY; 
     opts.argv = NULL;
     opts.parallelism = erts_port_parallelism;
+    erts_osenv_init(&opts.envir);
+
     linebuf = 0;
 
     *err_nump = 0;
@@ -718,11 +720,16 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump)
 			goto badarg;
 		    }
 		} else if (option == am_env) {
-                    if (opts.envir) /* ignore previous env option... */
-                        erts_free(ERTS_ALC_T_OPEN_PORT_ENV, opts.envir);
-                    opts.envir = convert_environment(*tp);
-                    if (!opts.envir)
-			goto badarg;
+		    if (merged_environment) {
+		        /* Ignore previous env option */
+		        erts_osenv_clear(&opts.envir);
+		    }
+
+		    merged_environment = 1;
+
+		    if (merge_global_environment(&opts.envir, *tp)) {
+		        goto badarg;
+		    }
 		} else if (option == am_args) {
 		    char **av;
 		    char **oav = opts.argv;
@@ -807,6 +814,12 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump)
     if((linebuf && opts.packet_bytes) || 
        (opts.redir_stderr && !opts.use_stdio)) {
 	goto badarg;
+}
+
+    /* If we lacked an env option, fill in the global environment without
+     * changes. */
+    if (!merged_environment) {
+        merge_global_environment(&opts.envir, NIL);
     }
 
     /*
@@ -956,8 +969,7 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump)
 	erts_atomic32_read_bor_relb(&port->state, sflgs);
  
  do_return:
-    if (opts.envir)
-        erts_free(ERTS_ALC_T_OPEN_PORT_ENV, opts.envir);
+    erts_osenv_clear(&opts.envir);
     if (name_buf)
 	erts_free(ERTS_ALC_T_TMP, (void *) name_buf);
     if (opts.argv) {
@@ -977,6 +989,45 @@ open_port(Process* p, Eterm name, Eterm settings, int *err_typep, int *err_nump)
     goto do_return;
 }
 
+/* Merges the the global environment and the given {Key, Value} list into env,
+ * unsetting all keys whose value is either 'false' or NIL. The behavior on
+ * NIL is undocumented and perhaps surprising, but the previous implementation
+ * worked in this manner. */
+static int merge_global_environment(erts_osenv_t *env, Eterm key_value_pairs) {
+    const erts_osenv_t *global_env = erts_sys_rlock_global_osenv();
+    erts_osenv_merge(env, global_env, 0);
+    erts_sys_runlock_global_osenv();
+
+    while (is_list(key_value_pairs)) {
+        Eterm *cell, *tuple;
+
+        cell = list_val(key_value_pairs);
+
+        if(!is_tuple_arity(CAR(cell), 2)) {
+            return -1;
+        }
+
+        tuple = tuple_val(CAR(cell));
+        key_value_pairs = CDR(cell);
+
+        if(is_nil(tuple[2]) || tuple[2] == am_false) {
+            if(erts_osenv_unset_term(env, tuple[1]) < 0) {
+                return -1;
+            }
+        } else {
+            if(erts_osenv_put_term(env, tuple[1], tuple[2]) < 0) {
+                return -1;
+            }
+        }
+    }
+
+    if(!is_nil(key_value_pairs)) {
+        return -1;
+    }
+
+    return 0;
+}
+
 /* Arguments can be given i unicode and as raw binaries, convert filename is used to convert */
 static char **convert_args(Eterm l)
 {
@@ -1024,130 +1075,6 @@ static void free_args(char **av)
     erts_free(ERTS_ALC_T_TMP, av);
 }
 
-#ifdef DEBUG
-#define ERTS_CONV_ENV_BUF_EXTRA 2
-#else
-#define ERTS_CONV_ENV_BUF_EXTRA 1024
-#endif
-
-static char* convert_environment(Eterm env)
-{
-    /*
-     * Returns environment buffer in memory allocated
-     * as ERTS_ALC_T_OPEN_PORT_ENV. Caller *needs*
-     * to deallocate...
-     */
-
-    Sint size, alloc_size;
-    byte* bytes;
-    int encoding = erts_get_native_filename_encoding();
-
-    alloc_size = ERTS_CONV_ENV_BUF_EXTRA;
-    bytes = erts_alloc(ERTS_ALC_T_OPEN_PORT_ENV,
-                       alloc_size);
-    size = 0;
-
-    /* ERTS_CONV_ENV_BUF_EXTRA >= for end delimiter... */
-    ERTS_CT_ASSERT(ERTS_CONV_ENV_BUF_EXTRA >= 2);
-
-    while (is_list(env)) {
-        Sint var_sz, val_sz, need;
-        byte *str, *limit;
-	Eterm tmp, *tp, *consp;
-
-        consp = list_val(env);
-	tmp = CAR(consp);
-	if (is_not_tuple_arity(tmp, 2))
-	    goto error;
-
-	tp = tuple_val(tmp);
-
-        /* Check encoding of env variable... */
-        if (is_not_list(tp[1]))
-            goto error;
-        var_sz = erts_native_filename_need(tp[1], encoding);
-        if (var_sz <= 0)
-            goto error;
-        /* Check encoding of value... */
-        if (tp[2] == am_false || is_nil(tp[2]))
-            val_sz = 0;
-        else if (is_not_list(tp[2]))
-            goto error;
-        else {
-            val_sz = erts_native_filename_need(tp[2], encoding);
-            if (val_sz < 0)
-                goto error;
-        }
-
-        /* Ensure enough memory... */
-        need = size;
-        need += var_sz + val_sz;
-        /* '=' and '\0' */
-        need += 2 * erts_raw_env_7bit_ascii_char_need(encoding);
-        if (need > alloc_size) {
-            alloc_size = (need - alloc_size) + alloc_size;
-            alloc_size += ERTS_CONV_ENV_BUF_EXTRA;
-            bytes = erts_realloc(ERTS_ALC_T_OPEN_PORT_ENV,
-                                 bytes, alloc_size);
-        }
-
-        /* Write environment variable name... */
-        str = bytes + size;
-        erts_native_filename_put(tp[1], encoding, str);
-        /* empty variable name is not allowed... */
-        if (erts_raw_env_char_is_7bit_ascii_char('\0', str, encoding))
-            goto error;
-
-        /*
-         * Drop null characters at the end and verify that we do
-         * not have any '=' characters in the name...
-         */
-        limit = str + var_sz;
-        while (str < limit) {
-            if (erts_raw_env_char_is_7bit_ascii_char('\0', str, encoding))
-                break;
-            if (erts_raw_env_char_is_7bit_ascii_char('=', str, encoding))
-                goto error;
-            str = erts_raw_env_next_char(str, encoding);
-        }
-
-        /* Write the equals sign... */
-        str = erts_raw_env_7bit_ascii_char_put('=', str, encoding);
-
-        /* Write the value... */
-        if (val_sz > 0) {
-            limit = str + val_sz;
-            erts_native_filename_put(tp[2], encoding, str);
-            while (str < limit) {
-                if (erts_raw_env_char_is_7bit_ascii_char('\0', str, encoding))
-                    break;
-                str = erts_raw_env_next_char(str, encoding);
-            }
-        }
-
-        /* Delimit... */
-        str = erts_raw_env_7bit_ascii_char_put('\0', str, encoding);
-
-        size = str - bytes;
-        ASSERT(size <= alloc_size);
-
-        env = CDR(consp);
-    }
-
-    /* End delimit... */
-    (void) erts_raw_env_7bit_ascii_char_put('\0', &bytes[size], encoding);
-
-    if (is_nil(env))
-        return (char *) bytes;
-
-error:
-
-    if (bytes)
-        erts_free(ERTS_ALC_T_OPEN_PORT_ENV, bytes);
-
-    return (char *) NULL; /* error... */
-}
-
 /* ------------ decode_packet() and friends: */
 
 struct packet_callback_args
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 6cef9bd0e3..f52eed41d5 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -50,7 +50,7 @@
 #define ERTS_WANT_TIMER_WHEEL_API
 #include "erl_time.h"
 #include "erl_check_io.h"
-
+#include "erl_osenv.h"
 #ifdef HIPE
 #include "hipe_mode_switch.h"	/* for hipe_mode_switch_init() */
 #include "hipe_signal.h"	/* for hipe_signal_init() */
@@ -803,8 +803,9 @@ early_init(int *argc, char **argv) /*
 
     envbufsz = sizeof(envbuf);
 
-    /* erts_sys_getenv(_raw)() not initialized yet; need erts_sys_getenv__() */
-    if (erts_sys_getenv__("ERL_THREAD_POOL_SIZE", envbuf, &envbufsz) == 0)
+    /* erts_osenv hasn't been initialized yet, so we need to fall back to
+     * erts_sys_explicit_host_getenv() */
+    if (erts_sys_explicit_host_getenv("ERL_THREAD_POOL_SIZE", envbuf, &envbufsz) == 1)
 	erts_async_max_threads = atoi(envbuf);
     else
 	erts_async_max_threads = ERTS_DEFAULT_NO_ASYNC_THREADS;
@@ -1210,20 +1211,20 @@ erl_start(int argc, char **argv)
 			 &time_warp_mode);
 
     envbufsz = sizeof(envbuf);
-    if (erts_sys_getenv_raw(ERL_MAX_ETS_TABLES_ENV, envbuf, &envbufsz) == 0)
+    if (erts_sys_explicit_8bit_getenv(ERL_MAX_ETS_TABLES_ENV, envbuf, &envbufsz) == 1)
 	user_requested_db_max_tabs = atoi(envbuf);
     else
 	user_requested_db_max_tabs = 0;
 
     envbufsz = sizeof(envbuf);
-    if (erts_sys_getenv_raw("ERL_FULLSWEEP_AFTER", envbuf, &envbufsz) == 0) {
+    if (erts_sys_explicit_8bit_getenv("ERL_FULLSWEEP_AFTER", envbuf, &envbufsz) == 1) {
 	Uint16 max_gen_gcs = atoi(envbuf);
 	erts_atomic32_set_nob(&erts_max_gen_gcs,
 				  (erts_aint32_t) max_gen_gcs);
     }
 
     envbufsz = sizeof(envbuf);
-    if (erts_sys_getenv_raw("ERL_MAX_PORTS", envbuf, &envbufsz) == 0) {
+    if (erts_sys_explicit_8bit_getenv("ERL_MAX_PORTS", envbuf, &envbufsz) == 1) {
 	port_tab_sz = atoi(envbuf);
 	port_tab_sz_ignore_files = 1;
     }
diff --git a/erts/emulator/beam/erl_unicode.c b/erts/emulator/beam/erl_unicode.c
index b7a5c45fea..bd5439ba24 100644
--- a/erts/emulator/beam/erl_unicode.c
+++ b/erts/emulator/beam/erl_unicode.c
@@ -2083,18 +2083,9 @@ char* erts_convert_filename_to_wchar(byte* bytes, Uint size,
     return name_buf;
 }
 
-
-static int filename_len_16bit(byte *str) 
-{
-    byte *p = str;
-    while(*p != '\0' || p[1] != '\0') {
-	p += 2;
-    }
-    return (p - str);
-}
-Eterm erts_convert_native_to_filename(Process *p, byte *bytes)
+Eterm erts_convert_native_to_filename(Process *p, size_t size, byte *bytes)
 {
-    Uint size,num_chars;
+    Uint num_chars;
     Eterm *hp;
     byte *err_pos;
     Uint num_built; /* characters */
@@ -2108,7 +2099,6 @@ Eterm erts_convert_native_to_filename(Process *p, byte *bytes)
     case ERL_FILENAME_UTF8_MAC:
 	mac = 1;
     case ERL_FILENAME_UTF8:
-	size = strlen((char *) bytes);
 	if (size == 0)
 	    return NIL;
 	if (erts_analyze_utf8(bytes,size,&err_pos,&num_chars,NULL) != ERTS_UTF8_OK) {
@@ -2123,7 +2113,6 @@ Eterm erts_convert_native_to_filename(Process *p, byte *bytes)
 	} 
 	return ret;
     case ERL_FILENAME_WIN_WCHAR:
-	size=filename_len_16bit(bytes);
 	if ((size % 2) != 0) { /* Panic fixup to avoid crashing the emulator */
 	    size--;
 	    hp = HAlloc(p, size+2);
@@ -2146,7 +2135,6 @@ Eterm erts_convert_native_to_filename(Process *p, byte *bytes)
 	goto noconvert;
     }
  noconvert:
-    size = strlen((char *) bytes);
     hp = HAlloc(p, 2 * size);
     return erts_bin_bytes_to_list(NIL, hp, bytes, size, 0);
 }
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 09207364eb..09500c5bc0 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1264,7 +1264,7 @@ char* erts_convert_filename_to_wchar(byte* bytes, Uint size,
                                      char *statbuf, size_t statbuf_size,
                                      ErtsAlcType_t alloc_type, Sint* used,
                                      Uint extra_wchars);
-Eterm erts_convert_native_to_filename(Process *p, byte *bytes);
+Eterm erts_convert_native_to_filename(Process *p, size_t size, byte *bytes);
 Eterm erts_utf8_to_list(Process *p, Uint num, byte *bytes, Uint sz, Uint left,
 			Uint *num_built, Uint *num_eaten, Eterm tail);
 int erts_utf8_to_latin1(byte* dest, const byte* source, int slen);
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 9933c8dda4..6158e9613a 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -7715,13 +7715,27 @@ int null_func(void)
 int
 erl_drv_putenv(const char *key, char *value)
 {
-    return erts_sys_putenv_raw((char*)key, value);
+    switch (erts_sys_explicit_8bit_putenv((char*)key, value)) {
+    case -1: /* Insufficient buffer space */
+        return 1;
+    case 1: /* Success */
+        return 0;
+    default: /* Not found */
+        return -1;
+    }
 }
 
 int
 erl_drv_getenv(const char *key, char *value, size_t *value_size)
 {
-    return erts_sys_getenv_raw((char*)key, value, value_size);
+    switch (erts_sys_explicit_8bit_getenv((char*)key, value, value_size)) {
+    case -1: /* Insufficient buffer space */
+        return 1;
+    case 1: /* Success */
+        return 0;
+    default: /* Not found */
+        return -1;
+    }
 }
 
 /* get heart_port
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index bf7d310568..290e0b209a 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -636,6 +636,8 @@ typedef struct preload {
  */
 typedef Eterm ErtsTracer;
 
+#include "erl_osenv.h"
+
 /*
  * This structure contains options to all built in drivers.
  * None of the drivers use all of the fields.
@@ -651,8 +653,7 @@ typedef struct _SysDriverOpts {
     int hide_window;		/* Hide this windows (Windows). */
     int exit_status;		/* Report exit status of subprocess. */
     int overlapped_io;          /* Only has effect on windows NT et al */
-    char *envir;		/* Environment of the port process, */
-				/* in Windows format. */
+    erts_osenv_t envir;		/* Environment of the port process */
     char **argv;                /* Argument vector in Unix'ish format. */
     char *wd;			/* Working directory. */
     unsigned spawn_type;        /* Bitfield of ERTS_SPAWN_DRIVER | 
@@ -782,9 +783,6 @@ void set_break_quit(void (*)(void), void (*)(void));
 
 void os_flavor(char*, unsigned);
 void os_version(int*, int*, int*);
-void init_getenv_state(GETENV_STATE *);
-char * getenv_string(GETENV_STATE *);
-void fini_getenv_state(GETENV_STATE *);
 
 #define HAVE_ERTS_CHECK_IO_DEBUG
 typedef struct {
@@ -805,20 +803,21 @@ int sys_double_to_chars_ext(double, char*, size_t, size_t);
 int sys_double_to_chars_fast(double, char*, int, int, int);
 void sys_get_pid(char *, size_t);
 
-/* erts_sys_putenv() returns, 0 on success and a value != 0 on failure. */
-int erts_sys_putenv(char *key, char *value);
-/* Simple variant used from drivers, raw eightbit interface */
-int erts_sys_putenv_raw(char *key, char *value);
-/* erts_sys_getenv() returns 0 on success (length of value string in
-   *size), a value > 0 if value buffer is too small (*size is set to needed
-   size), and a value < 0 on failure. */
-int erts_sys_getenv(char *key, char *value, size_t *size);
-/* Simple variant used from drivers, raw eightbit interface */
-int erts_sys_getenv_raw(char *key, char *value, size_t *size);
-/* erts_sys_getenv__() is only allowed to be used in early init phase */
-int erts_sys_getenv__(char *key, char *value, size_t *size);
-/* erst_sys_unsetenv() returns 0 on success and a value != 0 on failure. */
-int erts_sys_unsetenv(char *key);
+/* erl_drv_get/putenv have been implicitly 8-bit for so long that we can't
+ * change them without breaking things on Windows. Their return values are
+ * identical to erts_osenv_get/putenv */
+int erts_sys_explicit_8bit_getenv(char *key, char *value, size_t *size);
+int erts_sys_explicit_8bit_putenv(char *key, char *value);
+
+/* This is identical to erts_sys_explicit_8bit_getenv but falls down to the
+ * host OS implementation instead of erts_osenv. */
+int erts_sys_explicit_host_getenv(char *key, char *value, size_t *size);
+
+const erts_osenv_t *erts_sys_rlock_global_osenv(void);
+void erts_sys_runlock_global_osenv(void);
+
+erts_osenv_t *erts_sys_rwlock_global_osenv(void);
+void erts_sys_rwunlock_global_osenv(void);
 
 /* Easier to use, but not as efficient, environment functions */
 char *erts_read_env(char *key);
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index 993585be10..fe9f1c7606 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -4360,15 +4360,20 @@ erts_read_env(char *key)
     char *value = erts_alloc(ERTS_ALC_T_TMP, value_len);
     int res;
     while (1) {
-	res = erts_sys_getenv_raw(key, value, &value_len);
-	if (res <= 0)
-	    break;
-	value = erts_realloc(ERTS_ALC_T_TMP, value, value_len);
+        res = erts_sys_explicit_8bit_getenv(key, value, &value_len);
+
+        if (res >= 0) {
+            break;
+        }
+
+        value = erts_realloc(ERTS_ALC_T_TMP, value, value_len);
     }
-    if (res != 0) {
-	erts_free(ERTS_ALC_T_TMP, value);
-	return NULL;
+
+    if (res != 1) {
+        erts_free(ERTS_ALC_T_TMP, value);
+        return NULL;
     }
+
     return value;
 }