auto import from //depot/cupcake/@135843

libc/bionic/system_properties.c

@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stddef.h>
+#include <errno.h>
+
+#include <sys/mman.h>
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/select.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
+#include <sys/atomics.h>
+
+static const char property_service_name[] = PROP_SERVICE_NAME;
+
+static unsigned dummy_props = 0;
+
+prop_area *__system_property_area__ = (void*) &dummy_props;
+
+int __system_properties_init(void)
+{
+    prop_area *pa;
+    int s, fd;
+    unsigned sz;
+    char *env;
+
+    if(__system_property_area__ != ((void*) &dummy_props)) {
+        return 0;
+    }
+
+    env = getenv("ANDROID_PROPERTY_WORKSPACE");
+    if (!env) {
+        return -1;
+    }
+    fd = atoi(env);
+    env = strchr(env, ',');
+    if (!env) {
+        return -1;
+    }
+    sz = atoi(env + 1);
+    
+    pa = mmap(0, sz, PROT_READ, MAP_SHARED, fd, 0);
+    
+    if(pa == MAP_FAILED) {
+        return -1;
+    }
+
+    if((pa->magic != PROP_AREA_MAGIC) || (pa->version != PROP_AREA_VERSION)) {
+        munmap(pa, sz);
+        return -1;
+    }
+
+    __system_property_area__ = pa;
+    return 0;
+}
+
+const prop_info *__system_property_find_nth(unsigned n)
+{
+    prop_area *pa = __system_property_area__;
+
+    if(n >= pa->count) {
+        return 0;
+    } else {
+        return TOC_TO_INFO(pa, pa->toc[n]);
+    }
+}
+
+const prop_info *__system_property_find(const char *name)
+{
+    prop_area *pa = __system_property_area__;
+    unsigned count = pa->count;
+    unsigned *toc = pa->toc;
+    unsigned len = strlen(name);
+    prop_info *pi;
+
+    while(count--) {
+        unsigned entry = *toc++;
+        if(TOC_NAME_LEN(entry) != len) continue;
+        
+        pi = TOC_TO_INFO(pa, entry);
+        if(memcmp(name, pi->name, len)) continue;
+
+        return pi;
+    }
+
+    return 0;
+}
+
+int __system_property_read(const prop_info *pi, char *name, char *value)
+{
+    unsigned serial, len;
+    
+    for(;;) {
+        serial = pi->serial;
+        while(SERIAL_DIRTY(serial)) {
+            __futex_wait(&pi->serial, serial, 0);
+            serial = pi->serial;
+        }
+        len = SERIAL_VALUE_LEN(serial);
+        memcpy(value, pi->value, len + 1);
+        if(serial == pi->serial) {
+            if(name != 0) {
+                strcpy(name, pi->name);
+            }
+            return len;
+        }
+    }
+}
+
+int __system_property_get(const char *name, char *value)
+{
+    const prop_info *pi = __system_property_find(name);
+
+    if(pi != 0) {
+        return __system_property_read(pi, 0, value);
+    } else {
+        value[0] = 0;
+        return 0;
+    }
+}
+
+int __system_property_wait(const prop_info *pi)
+{
+    unsigned n;
+    if(pi == 0) {
+        prop_area *pa = __system_property_area__;
+        n = pa->serial;
+        do {
+            __futex_wait(&pa->serial, n, 0);
+        } while(n == pa->serial);
+    } else {
+        n = pi->serial;
+        do {
+            __futex_wait(&pi->serial, n, 0);
+        } while(n == pi->serial);
+    }
+    return 0;
+}