diff options
Diffstat (limited to 'libc/bionic/system_properties.c')
| -rw-r--r-- | libc/bionic/system_properties.c | 91 |
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); |