23bc3ff71d
Depends on init change I8dd685ea Bug: 4185486 Change-Id: I5a2dbc3b7be1759212d4a3988d9033b9b947a1db
247 lines
6.4 KiB
C
247 lines
6.4 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stddef.h>
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#include <errno.h>
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#include <poll.h>
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#include <sys/mman.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <sys/select.h>
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <unistd.h>
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#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
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#include <sys/_system_properties.h>
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#include <sys/atomics.h>
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static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
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static unsigned dummy_props = 0;
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prop_area *__system_property_area__ = (void*) &dummy_props;
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int __system_properties_init(void)
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{
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prop_area *pa;
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int s, fd;
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unsigned sz;
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char *env;
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if(__system_property_area__ != ((void*) &dummy_props)) {
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return 0;
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}
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env = getenv("ANDROID_PROPERTY_WORKSPACE");
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if (!env) {
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return -1;
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}
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fd = atoi(env);
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env = strchr(env, ',');
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if (!env) {
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return -1;
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}
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sz = atoi(env + 1);
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pa = mmap(0, sz, PROT_READ, MAP_SHARED, fd, 0);
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if(pa == MAP_FAILED) {
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return -1;
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}
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if((pa->magic != PROP_AREA_MAGIC) || (pa->version != PROP_AREA_VERSION)) {
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munmap(pa, sz);
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return -1;
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}
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__system_property_area__ = pa;
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return 0;
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}
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const prop_info *__system_property_find_nth(unsigned n)
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{
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prop_area *pa = __system_property_area__;
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if(n >= pa->count) {
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return 0;
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} else {
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return TOC_TO_INFO(pa, pa->toc[n]);
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}
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}
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const prop_info *__system_property_find(const char *name)
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{
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prop_area *pa = __system_property_area__;
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unsigned count = pa->count;
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unsigned *toc = pa->toc;
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unsigned len = strlen(name);
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prop_info *pi;
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while(count--) {
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unsigned entry = *toc++;
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if(TOC_NAME_LEN(entry) != len) continue;
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pi = TOC_TO_INFO(pa, entry);
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if(memcmp(name, pi->name, len)) continue;
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return pi;
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}
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return 0;
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}
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int __system_property_read(const prop_info *pi, char *name, char *value)
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{
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unsigned serial, len;
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for(;;) {
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serial = pi->serial;
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while(SERIAL_DIRTY(serial)) {
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__futex_wait((volatile void *)&pi->serial, serial, 0);
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serial = pi->serial;
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}
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len = SERIAL_VALUE_LEN(serial);
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memcpy(value, pi->value, len + 1);
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if(serial == pi->serial) {
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if(name != 0) {
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strcpy(name, pi->name);
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}
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return len;
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}
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}
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}
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int __system_property_get(const char *name, char *value)
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{
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const prop_info *pi = __system_property_find(name);
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if(pi != 0) {
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return __system_property_read(pi, 0, value);
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} else {
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value[0] = 0;
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return 0;
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}
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}
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static int send_prop_msg(prop_msg *msg)
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{
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struct pollfd pollfds[1];
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struct sockaddr_un addr;
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socklen_t alen;
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size_t namelen;
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int s;
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int r;
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int result = -1;
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s = socket(AF_LOCAL, SOCK_STREAM, 0);
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if(s < 0) {
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return result;
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}
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memset(&addr, 0, sizeof(addr));
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namelen = strlen(property_service_socket);
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strlcpy(addr.sun_path, property_service_socket, sizeof addr.sun_path);
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addr.sun_family = AF_LOCAL;
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alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
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if(TEMP_FAILURE_RETRY(connect(s, (struct sockaddr *) &addr, alen) < 0)) {
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close(s);
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return result;
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}
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r = TEMP_FAILURE_RETRY(send(s, msg, sizeof(prop_msg), 0));
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if(r == sizeof(prop_msg)) {
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// We successfully wrote to the property server but now we
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// wait for the property server to finish its work. It
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// acknowledges its completion by closing the socket so we
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// poll here (on nothing), waiting for the socket to close.
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// If you 'adb shell setprop foo bar' you'll see the POLLHUP
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// once the socket closes. Out of paranoia we cap our poll
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// at 250 ms.
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pollfds[0].fd = s;
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pollfds[0].events = 0;
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r = TEMP_FAILURE_RETRY(poll(pollfds, 1, 250 /* ms */));
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if (r == 1 && (pollfds[0].revents & POLLHUP) != 0) {
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result = 0;
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}
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}
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close(s);
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return result;
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}
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int __system_property_set(const char *key, const char *value)
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{
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int err;
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int tries = 0;
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int update_seen = 0;
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prop_msg msg;
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if(key == 0) return -1;
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if(value == 0) value = "";
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if(strlen(key) >= PROP_NAME_MAX) return -1;
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if(strlen(value) >= PROP_VALUE_MAX) return -1;
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memset(&msg, 0, sizeof msg);
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msg.cmd = PROP_MSG_SETPROP;
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strlcpy(msg.name, key, sizeof msg.name);
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strlcpy(msg.value, value, sizeof msg.value);
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err = send_prop_msg(&msg);
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if(err < 0) {
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return err;
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}
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return 0;
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}
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int __system_property_wait(const prop_info *pi)
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{
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unsigned n;
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if(pi == 0) {
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prop_area *pa = __system_property_area__;
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n = pa->serial;
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do {
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__futex_wait(&pa->serial, n, 0);
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} while(n == pa->serial);
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} else {
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n = pi->serial;
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do {
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__futex_wait((volatile void *)&pi->serial, n, 0);
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} while(n == pi->serial);
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}
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return 0;
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}
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