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-rw-r--r--libc/bionic/system_properties.c91
1 files changed, 25 insertions, 66 deletions
diff --git a/libc/bionic/system_properties.c b/libc/bionic/system_properties.c
index 126fea5..d4054d2 100644
--- a/libc/bionic/system_properties.c
+++ b/libc/bionic/system_properties.c
@@ -109,7 +109,7 @@ typedef struct prop_bt prop_bt;
static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
static char property_filename[PATH_MAX] = PROP_FILENAME;
-prop_area *__system_property_regions__[PA_REGION_COUNT] = { NULL, };
+prop_area *__system_property_area__ = NULL;
const size_t PA_DATA_SIZE = PA_SIZE - sizeof(prop_area);
@@ -124,15 +124,10 @@ static int get_fd_from_env(void)
return atoi(env);
}
-static int map_prop_region_rw(size_t region)
+static int map_prop_area_rw()
{
prop_area *pa;
int fd;
- size_t offset = region * PA_SIZE;
-
- if (__system_property_regions__[region]) {
- return 0;
- }
/* dev is a tmpfs that we can use to carve a shared workspace
* out of, so let's do that...
@@ -148,24 +143,21 @@ static int map_prop_region_rw(size_t region)
return -1;
}
- if (ftruncate(fd, offset + PA_SIZE) < 0)
+ if (ftruncate(fd, PA_SIZE) < 0)
goto out;
- pa = mmap(NULL, PA_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset);
+ pa = mmap(NULL, PA_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if(pa == MAP_FAILED)
goto out;
memset(pa, 0, PA_SIZE);
pa->magic = PROP_AREA_MAGIC;
pa->version = PROP_AREA_VERSION;
-
- if (!region) {
- /* reserve root node */
- pa->bytes_used += sizeof(prop_bt);
- }
+ /* reserve root node */
+ pa->bytes_used = sizeof(prop_bt);
/* plug into the lib property services */
- __system_property_regions__[region] = pa;
+ __system_property_area__ = pa;
close(fd);
return 0;
@@ -187,20 +179,14 @@ int __system_property_set_filename(const char *filename)
int __system_property_area_init()
{
- return map_prop_region_rw(0);
+ return map_prop_area_rw();
}
-static int map_prop_region(size_t region)
+static int map_prop_area()
{
bool fromFile = true;
- bool swapped;
- size_t offset = region * PA_SIZE;
int result = -1;
- if(__system_property_regions__[region]) {
- return 0;
- }
-
int fd = open(property_filename, O_RDONLY | O_NOFOLLOW);
if ((fd < 0) && (errno == ENOENT)) {
@@ -229,11 +215,11 @@ static int map_prop_region(size_t region)
if ((fd_stat.st_uid != 0)
|| (fd_stat.st_gid != 0)
|| ((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0)
- || (fd_stat.st_size < offset + PA_SIZE) ) {
+ || (fd_stat.st_size < PA_SIZE) ) {
goto cleanup;
}
- prop_area *pa = mmap(NULL, PA_SIZE, PROT_READ, MAP_SHARED, fd, offset);
+ prop_area *pa = mmap(NULL, PA_SIZE, PROT_READ, MAP_SHARED, fd, 0);
if (pa == MAP_FAILED) {
goto cleanup;
@@ -245,16 +231,8 @@ static int map_prop_region(size_t region)
}
result = 0;
- swapped = __sync_bool_compare_and_swap(&__system_property_regions__[region],
- NULL, pa);
- if (!swapped) {
- /**
- * In the event of a race either mapping is equally good, so
- * the thread that lost can just throw its mapping away and proceed as
- * normal.
- */
- munmap(pa, PA_SIZE);
- }
+
+ __system_property_area__ = pa;
cleanup:
if (fromFile) {
@@ -266,33 +244,20 @@ cleanup:
int __system_properties_init()
{
- return map_prop_region(0);
+ return map_prop_area();
}
static void *new_prop_obj(size_t size, prop_off_t *off)
{
- prop_area *pa;
- size_t i, idx;
+ prop_area *pa = __system_property_area__;
size = ALIGN(size, sizeof(uint32_t));
- for (i = 0; i < PA_REGION_COUNT; i++) {
- int err = map_prop_region_rw(i);
- if (err < 0) {
- return NULL;
- }
-
- pa = __system_property_regions__[i];
- if (pa->bytes_used + size <= PA_DATA_SIZE)
- break;
- }
-
- if (i == PA_REGION_COUNT)
+ if (pa->bytes_used + size > PA_DATA_SIZE)
return NULL;
- idx = pa->bytes_used;
- *off = idx + i * PA_DATA_SIZE;
- pa->bytes_used += size;
- return pa->data + idx;
+ *off = pa->bytes_used;
+ __system_property_area__->bytes_used += size;
+ return __system_property_area__->data + *off;
}
static prop_bt *new_prop_bt(const char *name, uint8_t namelen, prop_off_t *off)
@@ -330,16 +295,10 @@ static prop_info *new_prop_info(const char *name, uint8_t namelen,
static void *to_prop_obj(prop_off_t off)
{
- size_t region = off / PA_DATA_SIZE;
- size_t idx = off % PA_DATA_SIZE;
-
- if (region > PA_REGION_COUNT)
- return NULL;
-
- if (map_prop_region(region) < 0)
+ if (off > PA_DATA_SIZE)
return NULL;
- return __system_property_regions__[region]->data + idx;
+ return __system_property_area__->data + off;
}
static prop_bt *root_node()
@@ -570,7 +529,7 @@ int __system_property_wait(const prop_info *pi)
{
unsigned n;
if(pi == 0) {
- prop_area *pa = __system_property_regions__[0];
+ prop_area *pa = __system_property_area__;
n = pa->serial;
do {
__futex_wait(&pa->serial, n, 0);
@@ -586,7 +545,7 @@ int __system_property_wait(const prop_info *pi)
int __system_property_update(prop_info *pi, const char *value, unsigned int len)
{
- prop_area *pa = __system_property_regions__[0];
+ prop_area *pa = __system_property_area__;
if (len >= PROP_VALUE_MAX)
return -1;
@@ -607,7 +566,7 @@ int __system_property_update(prop_info *pi, const char *value, unsigned int len)
int __system_property_add(const char *name, unsigned int namelen,
const char *value, unsigned int valuelen)
{
- prop_area *pa = __system_property_regions__[0];
+ prop_area *pa = __system_property_area__;
const prop_info *pi;
if (namelen >= PROP_NAME_MAX)
@@ -633,7 +592,7 @@ unsigned int __system_property_serial(const prop_info *pi)
unsigned int __system_property_wait_any(unsigned int serial)
{
- prop_area *pa = __system_property_regions__[0];
+ prop_area *pa = __system_property_area__;
do {
__futex_wait(&pa->serial, serial, 0);