bionic: add compatibility mode for properties
Allow a new bionic to work with an old init property area by supporting
the old format.
(cherry picked from commit ad76c85b9ca587084089d086f954158bc0eae905)
Change-Id: Ib496e818a62a5834d40c71eb4745783d998be893
diff --git a/libc/Android.mk b/libc/Android.mk
index b239b745..eba0a00 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -149,6 +149,7 @@
bionic/strntoumax.c \
bionic/strtotimeval.c \
bionic/system_properties.c \
+ bionic/system_properties_compat.c \
bionic/tcgetpgrp.c \
bionic/tcsetpgrp.c \
bionic/thread_atexit.c \
diff --git a/libc/bionic/system_properties.c b/libc/bionic/system_properties.c
index 0d42195..4c2e5a2 100644
--- a/libc/bionic/system_properties.c
+++ b/libc/bionic/system_properties.c
@@ -109,6 +109,7 @@
static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
static char property_filename[PATH_MAX] = PROP_FILENAME;
+static bool compat_mode = false;
prop_area *__system_property_area__ = NULL;
@@ -156,6 +157,7 @@
pa_size = PA_SIZE;
pa_data_size = pa_size - sizeof(prop_area);
+ compat_mode = false;
pa = mmap(NULL, pa_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if(pa == MAP_FAILED)
@@ -246,11 +248,16 @@
goto cleanup;
}
- if((pa->magic != PROP_AREA_MAGIC) || (pa->version != PROP_AREA_VERSION)) {
+ if((pa->magic != PROP_AREA_MAGIC) || (pa->version != PROP_AREA_VERSION &&
+ pa->version != PROP_AREA_VERSION_COMPAT)) {
munmap(pa, pa_size);
goto cleanup;
}
+ if (pa->version == PROP_AREA_VERSION_COMPAT) {
+ compat_mode = true;
+ }
+
result = 0;
__system_property_area__ = pa;
@@ -425,6 +432,9 @@
const prop_info *__system_property_find(const char *name)
{
+ if (__predict_false(compat_mode)) {
+ return __system_property_find_compat(name);
+ }
return find_property(root_node(), name, strlen(name), NULL, 0, false);
}
@@ -432,6 +442,10 @@
{
unsigned serial, len;
+ if (__predict_false(compat_mode)) {
+ return __system_property_read_compat(pi, name, value);
+ }
+
for(;;) {
serial = pi->serial;
while(SERIAL_DIRTY(serial)) {
@@ -688,5 +702,8 @@
int __system_property_foreach(void (*propfn)(const prop_info *pi, void *cookie),
void *cookie)
{
+ if (__predict_false(compat_mode)) {
+ return __system_property_foreach_compat(propfn, cookie);
+ }
return foreach_property(0, propfn, cookie);
}
diff --git a/libc/bionic/system_properties_compat.c b/libc/bionic/system_properties_compat.c
new file mode 100644
index 0000000..6dbc4cc
--- /dev/null
+++ b/libc/bionic/system_properties_compat.c
@@ -0,0 +1,131 @@
+/*
+ * 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.
+ */
+
+/*
+ * This file is only used to provide backwards compatibility to property areas
+ * created by old versions of init, which occurs when an ota runs. The updater
+ * binary is compiled statically against the newest bionic, but the recovery
+ * ramdisk may be using an old version of init. This can all be removed once
+ * OTAs from pre-K versions are no longer supported.
+ */
+
+#include <string.h>
+#include <sys/atomics.h>
+
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
+#define TOC_NAME_LEN(toc) ((toc) >> 24)
+#define TOC_TO_INFO(area, toc) ((prop_info_compat*) (((char*) area) + ((toc) & 0xFFFFFF)))
+
+struct prop_area_compat {
+ unsigned volatile count;
+ unsigned volatile serial;
+ unsigned magic;
+ unsigned version;
+ unsigned toc[1];
+};
+
+typedef struct prop_area_compat prop_area_compat;
+
+struct prop_area;
+typedef struct prop_area prop_area;
+
+struct prop_info_compat {
+ char name[PROP_NAME_MAX];
+ unsigned volatile serial;
+ char value[PROP_VALUE_MAX];
+};
+
+typedef struct prop_info_compat prop_info_compat;
+
+extern prop_area *__system_property_area__;
+
+const prop_info *__system_property_find_compat(const char *name)
+{
+ prop_area_compat *pa = (prop_area_compat *)__system_property_area__;
+ unsigned count = pa->count;
+ unsigned *toc = pa->toc;
+ unsigned len = strlen(name);
+ prop_info_compat *pi;
+
+ if (len >= PROP_NAME_MAX)
+ return 0;
+ if (len < 1)
+ return 0;
+
+ 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 (const prop_info *)pi;
+ }
+
+ return 0;
+}
+
+int __system_property_read_compat(const prop_info *_pi, char *name, char *value)
+{
+ unsigned serial, len;
+ const prop_info_compat *pi = (const prop_info_compat *)_pi;
+
+ for(;;) {
+ serial = pi->serial;
+ while(SERIAL_DIRTY(serial)) {
+ __futex_wait((volatile void *)&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_foreach_compat(
+ void (*propfn)(const prop_info *pi, void *cookie),
+ void *cookie)
+{
+ prop_area_compat *pa = (prop_area_compat *)__system_property_area__;
+ unsigned i;
+
+ for (i = 0; i < pa->count; i++) {
+ unsigned entry = pa->toc[i];
+ prop_info_compat *pi = TOC_TO_INFO(pa, entry);
+ propfn((const prop_info *)pi, cookie);
+ }
+
+ return 0;
+}
diff --git a/libc/include/sys/_system_properties.h b/libc/include/sys/_system_properties.h
index 92e35e1..5eee7f0 100644
--- a/libc/include/sys/_system_properties.h
+++ b/libc/include/sys/_system_properties.h
@@ -38,6 +38,7 @@
#define PROP_AREA_MAGIC 0x504f5250
#define PROP_AREA_VERSION 0xfc6ed0ab
+#define PROP_AREA_VERSION_COMPAT 0x45434f76
#define PROP_SERVICE_NAME "property_service"
#define PROP_FILENAME "/dev/__properties__"
@@ -129,6 +130,15 @@
** successive call. */
unsigned int __system_property_wait_any(unsigned int serial);
+/* Compatibility functions to support using an old init with a new libc,
+ ** mostly for the OTA updater binary. These can be deleted once OTAs from
+ ** a pre-K release no longer needed to be supported. */
+const prop_info *__system_property_find_compat(const char *name);
+int __system_property_read_compat(const prop_info *pi, char *name, char *value);
+int __system_property_foreach_compat(
+ void (*propfn)(const prop_info *pi, void *cookie),
+ void *cookie);
+
__END_DECLS
#endif
