#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
-#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
+#include <sys/uio.h>
#include <sys/un.h>
#include <sys/xattr.h>
#include <sys/_system_properties.h>
#include <sys/system_properties.h>
+#include <async_safe/log.h>
+
+#include "private/ErrnoRestorer.h"
#include "private/bionic_futex.h"
#include "private/bionic_lock.h"
#include "private/bionic_macros.h"
#include "private/bionic_sdk_version.h"
-#include "private/libc_logging.h"
static constexpr int PROP_FILENAME_MAX = 1024;
static constexpr size_t PA_SIZE = 128 * 1024;
-#define SERIAL_DIRTY(serial) ((serial) & 1)
+#define SERIAL_DIRTY(serial) ((serial)&1)
#define SERIAL_VALUE_LEN(serial) ((serial) >> 24)
static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
// Represents a node in the trie.
struct prop_bt {
- uint32_t namelen;
+ uint32_t namelen;
- // The property trie is updated only by the init process (single threaded) which provides
- // property service. And it can be read by multiple threads at the same time.
- // As the property trie is not protected by locks, we use atomic_uint_least32_t types for the
- // left, right, children "pointers" in the trie node. To make sure readers who see the
- // change of "pointers" can also notice the change of prop_bt structure contents pointed by
- // the "pointers", we always use release-consume ordering pair when accessing these "pointers".
+ // The property trie is updated only by the init process (single threaded) which provides
+ // property service. And it can be read by multiple threads at the same time.
+ // As the property trie is not protected by locks, we use atomic_uint_least32_t types for the
+ // left, right, children "pointers" in the trie node. To make sure readers who see the
+ // change of "pointers" can also notice the change of prop_bt structure contents pointed by
+ // the "pointers", we always use release-consume ordering pair when accessing these "pointers".
- // prop "points" to prop_info structure if there is a propery associated with the trie node.
- // Its situation is similar to the left, right, children "pointers". So we use
- // atomic_uint_least32_t and release-consume ordering to protect it as well.
+ // prop "points" to prop_info structure if there is a propery associated with the trie node.
+ // Its situation is similar to the left, right, children "pointers". So we use
+ // atomic_uint_least32_t and release-consume ordering to protect it as well.
- // We should also avoid rereading these fields redundantly, since not
- // all processor implementations ensure that multiple loads from the
- // same field are carried out in the right order.
- atomic_uint_least32_t prop;
+ // We should also avoid rereading these fields redundantly, since not
+ // all processor implementations ensure that multiple loads from the
+ // same field are carried out in the right order.
+ atomic_uint_least32_t prop;
- atomic_uint_least32_t left;
- atomic_uint_least32_t right;
+ atomic_uint_least32_t left;
+ atomic_uint_least32_t right;
- atomic_uint_least32_t children;
+ atomic_uint_least32_t children;
- char name[0];
+ char name[0];
- prop_bt(const char *name, const uint32_t name_length) {
- this->namelen = name_length;
- memcpy(this->name, name, name_length);
- this->name[name_length] = '\0';
- }
+ prop_bt(const char* name, const uint32_t name_length) {
+ this->namelen = name_length;
+ memcpy(this->name, name, name_length);
+ this->name[name_length] = '\0';
+ }
-private:
- DISALLOW_COPY_AND_ASSIGN(prop_bt);
+ private:
+ DISALLOW_COPY_AND_ASSIGN(prop_bt);
};
class prop_area {
-public:
-
- prop_area(const uint32_t magic, const uint32_t version) :
- magic_(magic), version_(version) {
- atomic_init(&serial_, 0);
- memset(reserved_, 0, sizeof(reserved_));
- // Allocate enough space for the root node.
- bytes_used_ = sizeof(prop_bt);
- }
+ public:
+ prop_area(const uint32_t magic, const uint32_t version) : magic_(magic), version_(version) {
+ atomic_init(&serial_, 0);
+ memset(reserved_, 0, sizeof(reserved_));
+ // Allocate enough space for the root node.
+ bytes_used_ = sizeof(prop_bt);
+ }
- const prop_info *find(const char *name);
- bool add(const char *name, unsigned int namelen,
- const char *value, unsigned int valuelen);
+ const prop_info* find(const char* name);
+ bool add(const char* name, unsigned int namelen, const char* value, unsigned int valuelen);
- bool foreach(void (*propfn)(const prop_info *pi, void *cookie), void *cookie);
+ bool foreach (void (*propfn)(const prop_info* pi, void* cookie), void* cookie);
- atomic_uint_least32_t *serial() { return &serial_; }
- uint32_t magic() const { return magic_; }
- uint32_t version() const { return version_; }
+ atomic_uint_least32_t* serial() {
+ return &serial_;
+ }
+ uint32_t magic() const {
+ return magic_;
+ }
+ uint32_t version() const {
+ return version_;
+ }
-private:
- void *allocate_obj(const size_t size, uint_least32_t *const off);
- prop_bt *new_prop_bt(const char *name, uint32_t namelen, uint_least32_t *const off);
- prop_info *new_prop_info(const char *name, uint32_t namelen,
- const char *value, uint32_t valuelen,
- uint_least32_t *const off);
- void *to_prop_obj(uint_least32_t off);
- prop_bt *to_prop_bt(atomic_uint_least32_t *off_p);
- prop_info *to_prop_info(atomic_uint_least32_t *off_p);
+ private:
+ void* allocate_obj(const size_t size, uint_least32_t* const off);
+ prop_bt* new_prop_bt(const char* name, uint32_t namelen, uint_least32_t* const off);
+ prop_info* new_prop_info(const char* name, uint32_t namelen, const char* value, uint32_t valuelen,
+ uint_least32_t* const off);
+ void* to_prop_obj(uint_least32_t off);
+ prop_bt* to_prop_bt(atomic_uint_least32_t* off_p);
+ prop_info* to_prop_info(atomic_uint_least32_t* off_p);
- prop_bt *root_node();
+ prop_bt* root_node();
- prop_bt *find_prop_bt(prop_bt *const bt, const char *name,
- uint32_t namelen, bool alloc_if_needed);
+ prop_bt* find_prop_bt(prop_bt* const bt, const char* name, uint32_t namelen, bool alloc_if_needed);
- const prop_info *find_property(prop_bt *const trie, const char *name,
- uint32_t namelen, const char *value,
- uint32_t valuelen, bool alloc_if_needed);
+ const prop_info* find_property(prop_bt* const trie, const char* name, uint32_t namelen,
+ const char* value, uint32_t valuelen, bool alloc_if_needed);
- bool foreach_property(prop_bt *const trie,
- void (*propfn)(const prop_info *pi, void *cookie),
- void *cookie);
+ bool foreach_property(prop_bt* const trie, void (*propfn)(const prop_info* pi, void* cookie),
+ void* cookie);
- uint32_t bytes_used_;
- atomic_uint_least32_t serial_;
- uint32_t magic_;
- uint32_t version_;
- uint32_t reserved_[28];
- char data_[0];
+ uint32_t bytes_used_;
+ atomic_uint_least32_t serial_;
+ uint32_t magic_;
+ uint32_t version_;
+ uint32_t reserved_[28];
+ char data_[0];
- DISALLOW_COPY_AND_ASSIGN(prop_area);
+ DISALLOW_COPY_AND_ASSIGN(prop_area);
};
struct prop_info {
- atomic_uint_least32_t serial;
- // we need to keep this buffer around because the property
- // value can be modified whereas name is constant.
- char value[PROP_VALUE_MAX];
- char name[0];
-
- prop_info(const char *name, uint32_t namelen, const char *value, uint32_t valuelen) {
- memcpy(this->name, name, namelen);
- this->name[namelen] = '\0';
- atomic_init(&this->serial, valuelen << 24);
- memcpy(this->value, value, valuelen);
- this->value[valuelen] = '\0';
- }
- private:
- DISALLOW_IMPLICIT_CONSTRUCTORS(prop_info);
-};
-
-struct find_nth_cookie {
- uint32_t count;
- const uint32_t n;
- const prop_info *pi;
+ atomic_uint_least32_t serial;
+ // we need to keep this buffer around because the property
+ // value can be modified whereas name is constant.
+ char value[PROP_VALUE_MAX];
+ char name[0];
+
+ prop_info(const char* name, uint32_t namelen, const char* value, uint32_t valuelen) {
+ memcpy(this->name, name, namelen);
+ this->name[namelen] = '\0';
+ atomic_init(&this->serial, valuelen << 24);
+ memcpy(this->value, value, valuelen);
+ this->value[valuelen] = '\0';
+ }
- explicit find_nth_cookie(uint32_t n) : count(0), n(n), pi(NULL) {
- }
+ private:
+ DISALLOW_IMPLICIT_CONSTRUCTORS(prop_info);
};
// This is public because it was exposed in the NDK. As of 2017-01, ~60 apps reference this symbol.
-// It's also used in a libnativehelper test.
prop_area* __system_property_area__ = nullptr;
static char property_filename[PROP_FILENAME_MAX] = PROP_FILENAME;
static prop_area* map_prop_area_rw(const char* filename, const char* context,
bool* fsetxattr_failed) {
- /* dev is a tmpfs that we can use to carve a shared workspace
- * out of, so let's do that...
- */
- const int fd = open(filename, O_RDWR | O_CREAT | O_NOFOLLOW | O_CLOEXEC | O_EXCL, 0444);
-
- if (fd < 0) {
- if (errno == EACCES) {
- /* for consistency with the case where the process has already
- * mapped the page in and segfaults when trying to write to it
- */
- abort();
- }
- return nullptr;
+ /* dev is a tmpfs that we can use to carve a shared workspace
+ * out of, so let's do that...
+ */
+ const int fd = open(filename, O_RDWR | O_CREAT | O_NOFOLLOW | O_CLOEXEC | O_EXCL, 0444);
+
+ if (fd < 0) {
+ if (errno == EACCES) {
+ /* for consistency with the case where the process has already
+ * mapped the page in and segfaults when trying to write to it
+ */
+ abort();
}
+ return nullptr;
+ }
- if (context) {
- if (fsetxattr(fd, XATTR_NAME_SELINUX, context, strlen(context) + 1, 0) != 0) {
- __libc_format_log(ANDROID_LOG_ERROR, "libc",
- "fsetxattr failed to set context (%s) for \"%s\"", context, filename);
- /*
- * fsetxattr() will fail during system properties tests due to selinux policy.
- * We do not want to create a custom policy for the tester, so we will continue in
- * this function but set a flag that an error has occurred.
- * Init, which is the only daemon that should ever call this function will abort
- * when this error occurs.
- * Otherwise, the tester will ignore it and continue, albeit without any selinux
- * property separation.
- */
- if (fsetxattr_failed) {
- *fsetxattr_failed = true;
- }
- }
+ if (context) {
+ if (fsetxattr(fd, XATTR_NAME_SELINUX, context, strlen(context) + 1, 0) != 0) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "fsetxattr failed to set context (%s) for \"%s\"", context, filename);
+ /*
+ * fsetxattr() will fail during system properties tests due to selinux policy.
+ * We do not want to create a custom policy for the tester, so we will continue in
+ * this function but set a flag that an error has occurred.
+ * Init, which is the only daemon that should ever call this function will abort
+ * when this error occurs.
+ * Otherwise, the tester will ignore it and continue, albeit without any selinux
+ * property separation.
+ */
+ if (fsetxattr_failed) {
+ *fsetxattr_failed = true;
+ }
}
+ }
- if (ftruncate(fd, PA_SIZE) < 0) {
- close(fd);
- return nullptr;
- }
+ if (ftruncate(fd, PA_SIZE) < 0) {
+ close(fd);
+ return nullptr;
+ }
- pa_size = PA_SIZE;
- pa_data_size = pa_size - sizeof(prop_area);
+ pa_size = PA_SIZE;
+ pa_data_size = pa_size - sizeof(prop_area);
- void *const memory_area = mmap(NULL, pa_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- if (memory_area == MAP_FAILED) {
- close(fd);
- return nullptr;
- }
+ void* const memory_area = mmap(nullptr, pa_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ if (memory_area == MAP_FAILED) {
+ close(fd);
+ return nullptr;
+ }
- prop_area *pa = new(memory_area) prop_area(PROP_AREA_MAGIC, PROP_AREA_VERSION);
+ prop_area* pa = new (memory_area) prop_area(PROP_AREA_MAGIC, PROP_AREA_VERSION);
- close(fd);
- return pa;
+ close(fd);
+ return pa;
}
static prop_area* map_fd_ro(const int fd) {
- struct stat fd_stat;
- if (fstat(fd, &fd_stat) < 0) {
- return nullptr;
- }
+ struct stat fd_stat;
+ if (fstat(fd, &fd_stat) < 0) {
+ return nullptr;
+ }
- if ((fd_stat.st_uid != 0)
- || (fd_stat.st_gid != 0)
- || ((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0)
- || (fd_stat.st_size < static_cast<off_t>(sizeof(prop_area))) ) {
- return nullptr;
- }
+ if ((fd_stat.st_uid != 0) || (fd_stat.st_gid != 0) ||
+ ((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0) ||
+ (fd_stat.st_size < static_cast<off_t>(sizeof(prop_area)))) {
+ return nullptr;
+ }
- pa_size = fd_stat.st_size;
- pa_data_size = pa_size - sizeof(prop_area);
+ pa_size = fd_stat.st_size;
+ pa_data_size = pa_size - sizeof(prop_area);
- void* const map_result = mmap(NULL, pa_size, PROT_READ, MAP_SHARED, fd, 0);
- if (map_result == MAP_FAILED) {
- return nullptr;
- }
+ void* const map_result = mmap(nullptr, pa_size, PROT_READ, MAP_SHARED, fd, 0);
+ if (map_result == MAP_FAILED) {
+ return nullptr;
+ }
-
prop_area* pa = reinterpret_cast<prop_area*>(map_result);
- if ((pa->magic() != PROP_AREA_MAGIC) || (pa->version() != PROP_AREA_VERSION)) {
- munmap(pa, pa_size);
- return nullptr;
- }
+ prop_area* pa = reinterpret_cast<prop_area*>(map_result);
+ if ((pa->magic() != PROP_AREA_MAGIC) || (pa->version() != PROP_AREA_VERSION)) {
+ munmap(pa, pa_size);
+ return nullptr;
+ }
- return pa;
+ return pa;
}
static prop_area* map_prop_area(const char* filename) {
- int fd = open(filename, O_CLOEXEC | O_NOFOLLOW | O_RDONLY);
- if (fd == -1) return nullptr;
+ int fd = open(filename, O_CLOEXEC | O_NOFOLLOW | O_RDONLY);
+ if (fd == -1) return nullptr;
- prop_area* map_result = map_fd_ro(fd);
- close(fd);
+ prop_area* map_result = map_fd_ro(fd);
+ close(fd);
- return map_result;
+ return map_result;
}
-void *prop_area::allocate_obj(const size_t size, uint_least32_t *const off)
-{
- const size_t aligned = BIONIC_ALIGN(size, sizeof(uint_least32_t));
- if (bytes_used_ + aligned > pa_data_size) {
- return NULL;
- }
+void* prop_area::allocate_obj(const size_t size, uint_least32_t* const off) {
+ const size_t aligned = BIONIC_ALIGN(size, sizeof(uint_least32_t));
+ if (bytes_used_ + aligned > pa_data_size) {
+ return nullptr;
+ }
- *off = bytes_used_;
- bytes_used_ += aligned;
- return data_ + *off;
+ *off = bytes_used_;
+ bytes_used_ += aligned;
+ return data_ + *off;
}
-prop_bt *prop_area::new_prop_bt(const char *name, uint32_t namelen, uint_least32_t *const off)
-{
- uint_least32_t new_offset;
- void *const p = allocate_obj(sizeof(prop_bt) + namelen + 1, &new_offset);
- if (p != NULL) {
- prop_bt* bt = new(p) prop_bt(name, namelen);
- *off = new_offset;
- return bt;
- }
+prop_bt* prop_area::new_prop_bt(const char* name, uint32_t namelen, uint_least32_t* const off) {
+ uint_least32_t new_offset;
+ void* const p = allocate_obj(sizeof(prop_bt) + namelen + 1, &new_offset);
+ if (p != nullptr) {
+ prop_bt* bt = new (p) prop_bt(name, namelen);
+ *off = new_offset;
+ return bt;
+ }
- return NULL;
+ return nullptr;
}
-prop_info *prop_area::new_prop_info(const char *name, uint32_t namelen,
- const char *value, uint32_t valuelen, uint_least32_t *const off)
-{
- uint_least32_t new_offset;
- void* const p = allocate_obj(sizeof(prop_info) + namelen + 1, &new_offset);
- if (p != NULL) {
- prop_info* info = new(p) prop_info(name, namelen, value, valuelen);
- *off = new_offset;
- return info;
- }
+prop_info* prop_area::new_prop_info(const char* name, uint32_t namelen, const char* value,
+ uint32_t valuelen, uint_least32_t* const off) {
+ uint_least32_t new_offset;
+ void* const p = allocate_obj(sizeof(prop_info) + namelen + 1, &new_offset);
+ if (p != nullptr) {
+ prop_info* info = new (p) prop_info(name, namelen, value, valuelen);
+ *off = new_offset;
+ return info;
+ }
- return NULL;
+ return nullptr;
}
-void *prop_area::to_prop_obj(uint_least32_t off)
-{
- if (off > pa_data_size)
- return NULL;
+void* prop_area::to_prop_obj(uint_least32_t off) {
+ if (off > pa_data_size) return nullptr;
- return (data_ + off);
+ return (data_ + off);
}
-inline prop_bt *prop_area::to_prop_bt(atomic_uint_least32_t* off_p) {
+inline prop_bt* prop_area::to_prop_bt(atomic_uint_least32_t* off_p) {
uint_least32_t off = atomic_load_explicit(off_p, memory_order_consume);
return reinterpret_cast<prop_bt*>(to_prop_obj(off));
}
-inline prop_info *prop_area::to_prop_info(atomic_uint_least32_t* off_p) {
+inline prop_info* prop_area::to_prop_info(atomic_uint_least32_t* off_p) {
uint_least32_t off = atomic_load_explicit(off_p, memory_order_consume);
return reinterpret_cast<prop_info*>(to_prop_obj(off));
}
-inline prop_bt *prop_area::root_node()
-{
- return reinterpret_cast<prop_bt*>(to_prop_obj(0));
+inline prop_bt* prop_area::root_node() {
+ return reinterpret_cast<prop_bt*>(to_prop_obj(0));
}
-static int cmp_prop_name(const char *one, uint32_t one_len, const char *two,
- uint32_t two_len)
-{
- if (one_len < two_len)
- return -1;
- else if (one_len > two_len)
- return 1;
- else
- return strncmp(one, two, one_len);
+static int cmp_prop_name(const char* one, uint32_t one_len, const char* two, uint32_t two_len) {
+ if (one_len < two_len)
+ return -1;
+ else if (one_len > two_len)
+ return 1;
+ else
+ return strncmp(one, two, one_len);
}
-prop_bt *prop_area::find_prop_bt(prop_bt *const bt, const char *name,
- uint32_t namelen, bool alloc_if_needed)
-{
+prop_bt* prop_area::find_prop_bt(prop_bt* const bt, const char* name, uint32_t namelen,
+ bool alloc_if_needed) {
+ prop_bt* current = bt;
+ while (true) {
+ if (!current) {
+ return nullptr;
+ }
+
+ const int ret = cmp_prop_name(name, namelen, current->name, current->namelen);
+ if (ret == 0) {
+ return current;
+ }
- prop_bt* current = bt;
- while (true) {
- if (!current) {
- return NULL;
+ if (ret < 0) {
+ uint_least32_t left_offset = atomic_load_explicit(¤t->left, memory_order_relaxed);
+ if (left_offset != 0) {
+ current = to_prop_bt(¤t->left);
+ } else {
+ if (!alloc_if_needed) {
+ return nullptr;
}
- const int ret = cmp_prop_name(name, namelen, current->name, current->namelen);
- if (ret == 0) {
- return current;
+ uint_least32_t new_offset;
+ prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
+ if (new_bt) {
+ atomic_store_explicit(¤t->left, new_offset, memory_order_release);
+ }
+ return new_bt;
+ }
+ } else {
+ uint_least32_t right_offset = atomic_load_explicit(¤t->right, memory_order_relaxed);
+ if (right_offset != 0) {
+ current = to_prop_bt(¤t->right);
+ } else {
+ if (!alloc_if_needed) {
+ return nullptr;
}
- if (ret < 0) {
- uint_least32_t left_offset = atomic_load_explicit(¤t->left, memory_order_relaxed);
- if (left_offset != 0) {
- current = to_prop_bt(¤t->left);
- } else {
- if (!alloc_if_needed) {
- return NULL;
- }
-
- uint_least32_t new_offset;
- prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
- if (new_bt) {
- atomic_store_explicit(¤t->left, new_offset, memory_order_release);
- }
- return new_bt;
- }
- } else {
- uint_least32_t right_offset = atomic_load_explicit(¤t->right, memory_order_relaxed);
- if (right_offset != 0) {
- current = to_prop_bt(¤t->right);
- } else {
- if (!alloc_if_needed) {
- return NULL;
- }
-
- uint_least32_t new_offset;
- prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
- if (new_bt) {
- atomic_store_explicit(¤t->right, new_offset, memory_order_release);
- }
- return new_bt;
- }
+ uint_least32_t new_offset;
+ prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
+ if (new_bt) {
+ atomic_store_explicit(¤t->right, new_offset, memory_order_release);
}
+ return new_bt;
+ }
}
+ }
}
-const prop_info *prop_area::find_property(prop_bt *const trie, const char *name,
- uint32_t namelen, const char *value, uint32_t valuelen,
- bool alloc_if_needed)
-{
- if (!trie) return NULL;
-
- const char *remaining_name = name;
- prop_bt* current = trie;
- while (true) {
- const char *sep = strchr(remaining_name, '.');
- const bool want_subtree = (sep != NULL);
- const uint32_t substr_size = (want_subtree) ?
- sep - remaining_name : strlen(remaining_name);
-
- if (!substr_size) {
- return NULL;
- }
+const prop_info* prop_area::find_property(prop_bt* const trie, const char* name, uint32_t namelen,
+ const char* value, uint32_t valuelen,
+ bool alloc_if_needed) {
+ if (!trie) return nullptr;
- prop_bt* root = NULL;
- uint_least32_t children_offset = atomic_load_explicit(¤t->children, memory_order_relaxed);
- if (children_offset != 0) {
- root = to_prop_bt(¤t->children);
- } else if (alloc_if_needed) {
- uint_least32_t new_offset;
- root = new_prop_bt(remaining_name, substr_size, &new_offset);
- if (root) {
- atomic_store_explicit(¤t->children, new_offset, memory_order_release);
- }
- }
+ const char* remaining_name = name;
+ prop_bt* current = trie;
+ while (true) {
+ const char* sep = strchr(remaining_name, '.');
+ const bool want_subtree = (sep != nullptr);
+ const uint32_t substr_size = (want_subtree) ? sep - remaining_name : strlen(remaining_name);
- if (!root) {
- return NULL;
- }
+ if (!substr_size) {
+ return nullptr;
+ }
- current = find_prop_bt(root, remaining_name, substr_size, alloc_if_needed);
- if (!current) {
- return NULL;
- }
+ prop_bt* root = nullptr;
+ uint_least32_t children_offset = atomic_load_explicit(¤t->children, memory_order_relaxed);
+ if (children_offset != 0) {
+ root = to_prop_bt(¤t->children);
+ } else if (alloc_if_needed) {
+ uint_least32_t new_offset;
+ root = new_prop_bt(remaining_name, substr_size, &new_offset);
+ if (root) {
+ atomic_store_explicit(¤t->children, new_offset, memory_order_release);
+ }
+ }
- if (!want_subtree)
- break;
+ if (!root) {
+ return nullptr;
+ }
- remaining_name = sep + 1;
+ current = find_prop_bt(root, remaining_name, substr_size, alloc_if_needed);
+ if (!current) {
+ return nullptr;
}
- uint_least32_t prop_offset = atomic_load_explicit(¤t->prop, memory_order_relaxed);
- if (prop_offset != 0) {
- return to_prop_info(¤t->prop);
- } else if (alloc_if_needed) {
- uint_least32_t new_offset;
- prop_info* new_info = new_prop_info(name, namelen, value, valuelen, &new_offset);
- if (new_info) {
- atomic_store_explicit(¤t->prop, new_offset, memory_order_release);
- }
+ if (!want_subtree) break;
- return new_info;
- } else {
- return NULL;
+ remaining_name = sep + 1;
+ }
+
+ uint_least32_t prop_offset = atomic_load_explicit(¤t->prop, memory_order_relaxed);
+ if (prop_offset != 0) {
+ return to_prop_info(¤t->prop);
+ } else if (alloc_if_needed) {
+ uint_least32_t new_offset;
+ prop_info* new_info = new_prop_info(name, namelen, value, valuelen, &new_offset);
+ if (new_info) {
+ atomic_store_explicit(¤t->prop, new_offset, memory_order_release);
}
+
+ return new_info;
+ } else {
+ return nullptr;
+ }
}
class PropertyServiceConnection {
public:
PropertyServiceConnection() : last_error_(0) {
- fd_ = socket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
- if (fd_ == -1) {
+ socket_ = ::socket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
+ if (socket_ == -1) {
last_error_ = errno;
return;
}
addr.sun_family = AF_LOCAL;
socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;
- if (TEMP_FAILURE_RETRY(connect(fd_, reinterpret_cast<sockaddr*>(&addr), alen)) == -1) {
- close(fd_);
- fd_ = -1;
+ if (TEMP_FAILURE_RETRY(connect(socket_, reinterpret_cast<sockaddr*>(&addr), alen)) == -1) {
last_error_ = errno;
+ close(socket_);
+ socket_ = -1;
}
}
bool IsValid() {
- return fd_ != -1;
+ return socket_ != -1;
}
int GetLastError() {
return last_error_;
}
- bool SendUint32(uint32_t value) {
- int result = TEMP_FAILURE_RETRY(send(fd_, &value, sizeof(value), 0));
- return CheckSendRecvResult(result, sizeof(value));
- }
-
- bool SendString(const char* value) {
- uint32_t valuelen = strlen(value);
- if (!SendUint32(valuelen)) {
- return false;
- }
-
- // Trying to send even 0 bytes to closed socket may lead to
- // broken pipe (http://b/34670529).
- if (valuelen == 0) {
- return true;
- }
-
- int result = TEMP_FAILURE_RETRY(send(fd_, value, valuelen, 0));
- return CheckSendRecvResult(result, valuelen);
- }
-
bool RecvInt32(int32_t* value) {
- int result = TEMP_FAILURE_RETRY(recv(fd_, value, sizeof(*value), MSG_WAITALL));
+ int result = TEMP_FAILURE_RETRY(recv(socket_, value, sizeof(*value), MSG_WAITALL));
return CheckSendRecvResult(result, sizeof(*value));
}
- int GetFd() {
- return fd_;
+ int socket() {
+ return socket_;
}
~PropertyServiceConnection() {
- if (fd_ != -1) {
- close(fd_);
+ if (socket_ != -1) {
+ close(socket_);
}
}
+
private:
bool CheckSendRecvResult(int result, int expected_len) {
if (result == -1) {
return last_error_ == 0;
}
- int fd_;
+ int socket_;
int last_error_;
-};
-struct prop_msg {
- unsigned cmd;
- char name[PROP_NAME_MAX];
- char value[PROP_VALUE_MAX];
+ friend class SocketWriter;
};
-static int send_prop_msg(const prop_msg* msg) {
- PropertyServiceConnection connection;
- if (!connection.IsValid()) {
- return connection.GetLastError();
+class SocketWriter {
+ public:
+ explicit SocketWriter(PropertyServiceConnection* connection)
+ : connection_(connection), iov_index_(0), uint_buf_index_(0)
+ {}
+
+ SocketWriter& WriteUint32(uint32_t value) {
+ CHECK(uint_buf_index_ < kUintBufSize);
+ CHECK(iov_index_ < kIovSize);
+ uint32_t* ptr = uint_buf_ + uint_buf_index_;
+ uint_buf_[uint_buf_index_++] = value;
+ iov_[iov_index_].iov_base = ptr;
+ iov_[iov_index_].iov_len = sizeof(*ptr);
+ ++iov_index_;
+ return *this;
+ }
+
+ SocketWriter& WriteString(const char* value) {
+ uint32_t valuelen = strlen(value);
+ WriteUint32(valuelen);
+ if (valuelen == 0) {
+ return *this;
}
- int result = -1;
- int fd = connection.GetFd();
-
- const int num_bytes = TEMP_FAILURE_RETRY(send(fd, msg, sizeof(prop_msg), 0));
- if (num_bytes == sizeof(prop_msg)) {
- // We successfully wrote to the property server but now we
- // wait for the property server to finish its work. It
- // acknowledges its completion by closing the socket so we
- // poll here (on nothing), waiting for the socket to close.
- // If you 'adb shell setprop foo bar' you'll see the POLLHUP
- // once the socket closes. Out of paranoia we cap our poll
- // at 250 ms.
- pollfd pollfds[1];
- pollfds[0].fd = fd;
- pollfds[0].events = 0;
- const int poll_result = TEMP_FAILURE_RETRY(poll(pollfds, 1, 250 /* ms */));
- if (poll_result == 1 && (pollfds[0].revents & POLLHUP) != 0) {
- result = 0;
- } else {
- // Ignore the timeout and treat it like a success anyway.
- // The init process is single-threaded and its property
- // service is sometimes slow to respond (perhaps it's off
- // starting a child process or something) and thus this
- // times out and the caller thinks it failed, even though
- // it's still getting around to it. So we fake it here,
- // mostly for ctl.* properties, but we do try and wait 250
- // ms so callers who do read-after-write can reliably see
- // what they've written. Most of the time.
- // TODO: fix the system properties design.
- __libc_format_log(ANDROID_LOG_WARN, "libc",
- "Property service has timed out while trying to set \"%s\" to \"%s\"",
- msg->name, msg->value);
- result = 0;
- }
+ CHECK(iov_index_ < kIovSize);
+ iov_[iov_index_].iov_base = const_cast<char*>(value);
+ iov_[iov_index_].iov_len = valuelen;
+ ++iov_index_;
+
+ return *this;
+ }
+
+ bool Send() {
+ if (!connection_->IsValid()) {
+ return false;
}
- return result;
-}
+ if (writev(connection_->socket(), iov_, iov_index_) == -1) {
+ connection_->last_error_ = errno;
+ return false;
+ }
-static void find_nth_fn(const prop_info *pi, void *ptr)
-{
- find_nth_cookie *cookie = reinterpret_cast<find_nth_cookie*>(ptr);
+ iov_index_ = uint_buf_index_ = 0;
+ return true;
+ }
- if (cookie->n == cookie->count)
- cookie->pi = pi;
+ private:
+ static constexpr size_t kUintBufSize = 8;
+ static constexpr size_t kIovSize = 8;
- cookie->count++;
-}
+ PropertyServiceConnection* connection_;
+ iovec iov_[kIovSize];
+ size_t iov_index_;
+ uint32_t uint_buf_[kUintBufSize];
+ size_t uint_buf_index_;
-bool prop_area::foreach_property(prop_bt *const trie,
- void (*propfn)(const prop_info *pi, void *cookie), void *cookie)
-{
- if (!trie)
- return false;
-
- uint_least32_t left_offset = atomic_load_explicit(&trie->left, memory_order_relaxed);
- if (left_offset != 0) {
- const int err = foreach_property(to_prop_bt(&trie->left), propfn, cookie);
- if (err < 0)
- return false;
- }
- uint_least32_t prop_offset = atomic_load_explicit(&trie->prop, memory_order_relaxed);
- if (prop_offset != 0) {
- prop_info *info = to_prop_info(&trie->prop);
- if (!info)
- return false;
- propfn(info, cookie);
- }
- uint_least32_t children_offset = atomic_load_explicit(&trie->children, memory_order_relaxed);
- if (children_offset != 0) {
- const int err = foreach_property(to_prop_bt(&trie->children), propfn, cookie);
- if (err < 0)
- return false;
- }
- uint_least32_t right_offset = atomic_load_explicit(&trie->right, memory_order_relaxed);
- if (right_offset != 0) {
- const int err = foreach_property(to_prop_bt(&trie->right), propfn, cookie);
- if (err < 0)
- return false;
+ DISALLOW_IMPLICIT_CONSTRUCTORS(SocketWriter);
+};
+
+struct prop_msg {
+ unsigned cmd;
+ char name[PROP_NAME_MAX];
+ char value[PROP_VALUE_MAX];
+};
+
+static int send_prop_msg(const prop_msg* msg) {
+ PropertyServiceConnection connection;
+ if (!connection.IsValid()) {
+ return connection.GetLastError();
+ }
+
+ int result = -1;
+ int s = connection.socket();
+
+ const int num_bytes = TEMP_FAILURE_RETRY(send(s, msg, sizeof(prop_msg), 0));
+ if (num_bytes == sizeof(prop_msg)) {
+ // We successfully wrote to the property server but now we
+ // wait for the property server to finish its work. It
+ // acknowledges its completion by closing the socket so we
+ // poll here (on nothing), waiting for the socket to close.
+ // If you 'adb shell setprop foo bar' you'll see the POLLHUP
+ // once the socket closes. Out of paranoia we cap our poll
+ // at 250 ms.
+ pollfd pollfds[1];
+ pollfds[0].fd = s;
+ pollfds[0].events = 0;
+ const int poll_result = TEMP_FAILURE_RETRY(poll(pollfds, 1, 250 /* ms */));
+ if (poll_result == 1 && (pollfds[0].revents & POLLHUP) != 0) {
+ result = 0;
+ } else {
+ // Ignore the timeout and treat it like a success anyway.
+ // The init process is single-threaded and its property
+ // service is sometimes slow to respond (perhaps it's off
+ // starting a child process or something) and thus this
+ // times out and the caller thinks it failed, even though
+ // it's still getting around to it. So we fake it here,
+ // mostly for ctl.* properties, but we do try and wait 250
+ // ms so callers who do read-after-write can reliably see
+ // what they've written. Most of the time.
+ // TODO: fix the system properties design.
+ async_safe_format_log(ANDROID_LOG_WARN, "libc",
+ "Property service has timed out while trying to set \"%s\" to \"%s\"",
+ msg->name, msg->value);
+ result = 0;
}
+ }
- return true;
+ return result;
}
-const prop_info *prop_area::find(const char *name) {
- return find_property(root_node(), name, strlen(name), nullptr, 0, false);
+bool prop_area::foreach_property(prop_bt* const trie,
+ void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
+ if (!trie) return false;
+
+ uint_least32_t left_offset = atomic_load_explicit(&trie->left, memory_order_relaxed);
+ if (left_offset != 0) {
+ const int err = foreach_property(to_prop_bt(&trie->left), propfn, cookie);
+ if (err < 0) return false;
+ }
+ uint_least32_t prop_offset = atomic_load_explicit(&trie->prop, memory_order_relaxed);
+ if (prop_offset != 0) {
+ prop_info* info = to_prop_info(&trie->prop);
+ if (!info) return false;
+ propfn(info, cookie);
+ }
+ uint_least32_t children_offset = atomic_load_explicit(&trie->children, memory_order_relaxed);
+ if (children_offset != 0) {
+ const int err = foreach_property(to_prop_bt(&trie->children), propfn, cookie);
+ if (err < 0) return false;
+ }
+ uint_least32_t right_offset = atomic_load_explicit(&trie->right, memory_order_relaxed);
+ if (right_offset != 0) {
+ const int err = foreach_property(to_prop_bt(&trie->right), propfn, cookie);
+ if (err < 0) return false;
+ }
+
+ return true;
+}
+
+const prop_info* prop_area::find(const char* name) {
+ return find_property(root_node(), name, strlen(name), nullptr, 0, false);
}
-bool prop_area::add(const char *name, unsigned int namelen,
- const char *value, unsigned int valuelen) {
- return find_property(root_node(), name, namelen, value, valuelen, true);
+bool prop_area::add(const char* name, unsigned int namelen, const char* value,
+ unsigned int valuelen) {
+ return find_property(root_node(), name, namelen, value, valuelen, true);
}
-bool prop_area::foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
- return foreach_property(root_node(), propfn, cookie);
+bool prop_area::foreach (void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
+ return foreach_property(root_node(), propfn, cookie);
}
class context_node {
-public:
- context_node(context_node* next, const char* context, prop_area* pa)
- : next(next), context_(strdup(context)), pa_(pa), no_access_(false) {
- lock_.init(false);
- }
- ~context_node() {
- unmap();
- free(context_);
- }
- bool open(bool access_rw, bool* fsetxattr_failed);
- bool check_access_and_open();
- void reset_access();
+ public:
+ context_node(context_node* next, const char* context, prop_area* pa)
+ : next(next), context_(strdup(context)), pa_(pa), no_access_(false) {
+ lock_.init(false);
+ }
+ ~context_node() {
+ unmap();
+ free(context_);
+ }
+ bool open(bool access_rw, bool* fsetxattr_failed);
+ bool check_access_and_open();
+ void reset_access();
- const char* context() const { return context_; }
- prop_area* pa() { return pa_; }
+ const char* context() const {
+ return context_;
+ }
+ prop_area* pa() {
+ return pa_;
+ }
- context_node* next;
+ context_node* next;
-private:
- bool check_access();
- void unmap();
+ private:
+ bool check_access();
+ void unmap();
- Lock lock_;
- char* context_;
- prop_area* pa_;
- bool no_access_;
+ Lock lock_;
+ char* context_;
+ prop_area* pa_;
+ bool no_access_;
};
struct prefix_node {
- prefix_node(struct prefix_node* next, const char* prefix, context_node* context)
- : prefix(strdup(prefix)), prefix_len(strlen(prefix)), context(context), next(next) {
- }
- ~prefix_node() {
- free(prefix);
- }
- char* prefix;
- const size_t prefix_len;
- context_node* context;
- struct prefix_node* next;
+ prefix_node(struct prefix_node* next, const char* prefix, context_node* context)
+ : prefix(strdup(prefix)), prefix_len(strlen(prefix)), context(context), next(next) {
+ }
+ ~prefix_node() {
+ free(prefix);
+ }
+ char* prefix;
+ const size_t prefix_len;
+ context_node* context;
+ struct prefix_node* next;
};
template <typename List, typename... Args>
static inline void list_add(List** list, Args... args) {
- *list = new List(*list, args...);
+ *list = new List(*list, args...);
}
static void list_add_after_len(prefix_node** list, const char* prefix, context_node* context) {
- size_t prefix_len = strlen(prefix);
+ size_t prefix_len = strlen(prefix);
- auto next_list = list;
+ auto next_list = list;
- while (*next_list) {
- if ((*next_list)->prefix_len < prefix_len || (*next_list)->prefix[0] == '*') {
- list_add(next_list, prefix, context);
- return;
- }
- next_list = &(*next_list)->next;
+ while (*next_list) {
+ if ((*next_list)->prefix_len < prefix_len || (*next_list)->prefix[0] == '*') {
+ list_add(next_list, prefix, context);
+ return;
}
- list_add(next_list, prefix, context);
+ next_list = &(*next_list)->next;
+ }
+ list_add(next_list, prefix, context);
}
template <typename List, typename Func>
static void list_foreach(List* list, Func func) {
- while (list) {
- func(list);
- list = list->next;
- }
+ while (list) {
+ func(list);
+ list = list->next;
+ }
}
template <typename List, typename Func>
static List* list_find(List* list, Func func) {
- while (list) {
- if (func(list)) {
- return list;
- }
- list = list->next;
+ while (list) {
+ if (func(list)) {
+ return list;
}
- return nullptr;
+ list = list->next;
+ }
+ return nullptr;
}
template <typename List>
static void list_free(List** list) {
- while (*list) {
- auto old_list = *list;
- *list = old_list->next;
- delete old_list;
- }
+ while (*list) {
+ auto old_list = *list;
+ *list = old_list->next;
+ delete old_list;
+ }
}
static prefix_node* prefixes = nullptr;
*/
bool context_node::open(bool access_rw, bool* fsetxattr_failed) {
- lock_.lock();
- if (pa_) {
- lock_.unlock();
- return true;
- }
-
- char filename[PROP_FILENAME_MAX];
- int len = __libc_format_buffer(filename, sizeof(filename), "%s/%s",
- property_filename, context_);
- if (len < 0 || len > PROP_FILENAME_MAX) {
- lock_.unlock();
- return false;
- }
+ lock_.lock();
+ if (pa_) {
+ lock_.unlock();
+ return true;
+ }
- if (access_rw) {
- pa_ = map_prop_area_rw(filename, context_, fsetxattr_failed);
- } else {
- pa_ = map_prop_area(filename);
- }
+ char filename[PROP_FILENAME_MAX];
+ int len = async_safe_format_buffer(filename, sizeof(filename), "%s/%s", property_filename,
+ context_);
+ if (len < 0 || len > PROP_FILENAME_MAX) {
lock_.unlock();
- return pa_;
+ return false;
+ }
+
+ if (access_rw) {
+ pa_ = map_prop_area_rw(filename, context_, fsetxattr_failed);
+ } else {
+ pa_ = map_prop_area(filename);
+ }
+ lock_.unlock();
+ return pa_;
}
bool context_node::check_access_and_open() {
- if (!pa_ && !no_access_) {
- if (!check_access() || !open(false, nullptr)) {
- no_access_ = true;
- }
+ if (!pa_ && !no_access_) {
+ if (!check_access() || !open(false, nullptr)) {
+ no_access_ = true;
}
- return pa_;
+ }
+ return pa_;
}
void context_node::reset_access() {
- if (!check_access()) {
- unmap();
- no_access_ = true;
- } else {
- no_access_ = false;
- }
+ if (!check_access()) {
+ unmap();
+ no_access_ = true;
+ } else {
+ no_access_ = false;
+ }
}
bool context_node::check_access() {
- char filename[PROP_FILENAME_MAX];
- int len = __libc_format_buffer(filename, sizeof(filename), "%s/%s",
- property_filename, context_);
- if (len < 0 || len > PROP_FILENAME_MAX) {
- return false;
- }
+ char filename[PROP_FILENAME_MAX];
+ int len = async_safe_format_buffer(filename, sizeof(filename), "%s/%s", property_filename,
+ context_);
+ if (len < 0 || len > PROP_FILENAME_MAX) {
+ return false;
+ }
- return access(filename, R_OK) == 0;
+ return access(filename, R_OK) == 0;
}
void context_node::unmap() {
- if (!pa_) {
- return;
- }
+ if (!pa_) {
+ return;
+ }
- munmap(pa_, pa_size);
- if (pa_ == __system_property_area__) {
- __system_property_area__ = nullptr;
- }
- pa_ = nullptr;
+ munmap(pa_, pa_size);
+ if (pa_ == __system_property_area__) {
+ __system_property_area__ = nullptr;
+ }
+ pa_ = nullptr;
}
static bool map_system_property_area(bool access_rw, bool* fsetxattr_failed) {
- char filename[PROP_FILENAME_MAX];
- int len = __libc_format_buffer(filename, sizeof(filename),
- "%s/properties_serial", property_filename);
- if (len < 0 || len > PROP_FILENAME_MAX) {
- __system_property_area__ = nullptr;
- return false;
- }
+ char filename[PROP_FILENAME_MAX];
+ int len =
+ async_safe_format_buffer(filename, sizeof(filename), "%s/properties_serial",
+ property_filename);
+ if (len < 0 || len > PROP_FILENAME_MAX) {
+ __system_property_area__ = nullptr;
+ return false;
+ }
- if (access_rw) {
- __system_property_area__ =
- map_prop_area_rw(filename, "u:object_r:properties_serial:s0", fsetxattr_failed);
- } else {
- __system_property_area__ = map_prop_area(filename);
- }
- return __system_property_area__;
+ if (access_rw) {
+ __system_property_area__ =
+ map_prop_area_rw(filename, "u:object_r:properties_serial:s0", fsetxattr_failed);
+ } else {
+ __system_property_area__ = map_prop_area(filename);
+ }
+ return __system_property_area__;
}
static prop_area* get_prop_area_for_name(const char* name) {
- auto entry = list_find(prefixes, [name](prefix_node* l) {
- return l->prefix[0] == '*' || !strncmp(l->prefix, name, l->prefix_len);
- });
- if (!entry) {
- return nullptr;
- }
+ auto entry = list_find(prefixes, [name](prefix_node* l) {
+ return l->prefix[0] == '*' || !strncmp(l->prefix, name, l->prefix_len);
+ });
+ if (!entry) {
+ return nullptr;
+ }
- auto cnode = entry->context;
- if (!cnode->pa()) {
- /*
- * We explicitly do not check no_access_ in this case because unlike the
- * case of foreach(), we want to generate an selinux audit for each
- * non-permitted property access in this function.
- */
- cnode->open(false, nullptr);
- }
- return cnode->pa();
+ auto cnode = entry->context;
+ if (!cnode->pa()) {
+ /*
+ * We explicitly do not check no_access_ in this case because unlike the
+ * case of foreach(), we want to generate an selinux audit for each
+ * non-permitted property access in this function.
+ */
+ cnode->open(false, nullptr);
+ }
+ return cnode->pa();
}
/*
*/
/* Read an entry from a spec file (e.g. file_contexts) */
-static inline int read_spec_entry(char **entry, char **ptr, int *len)
-{
- *entry = NULL;
- char *tmp_buf = NULL;
+static inline int read_spec_entry(char** entry, char** ptr, int* len) {
+ *entry = nullptr;
+ char* tmp_buf = nullptr;
- while (isspace(**ptr) && **ptr != '\0')
- (*ptr)++;
+ while (isspace(**ptr) && **ptr != '\0') (*ptr)++;
- tmp_buf = *ptr;
- *len = 0;
+ tmp_buf = *ptr;
+ *len = 0;
- while (!isspace(**ptr) && **ptr != '\0') {
- (*ptr)++;
- (*len)++;
- }
+ while (!isspace(**ptr) && **ptr != '\0') {
+ (*ptr)++;
+ (*len)++;
+ }
- if (*len) {
- *entry = strndup(tmp_buf, *len);
- if (!*entry)
- return -1;
- }
+ if (*len) {
+ *entry = strndup(tmp_buf, *len);
+ if (!*entry) return -1;
+ }
- return 0;
+ return 0;
}
/*
*
* This function calls read_spec_entry() to do the actual string processing.
*/
-static int read_spec_entries(char *line_buf, int num_args, ...)
-{
- char **spec_entry, *buf_p;
- int len, rc, items, entry_len = 0;
- va_list ap;
-
- len = strlen(line_buf);
- if (line_buf[len - 1] == '\n')
- line_buf[len - 1] = '\0';
- else
- /* Handle case if line not \n terminated by bumping
- * the len for the check below (as the line is NUL
- * terminated by getline(3)) */
- len++;
-
- buf_p = line_buf;
- while (isspace(*buf_p))
- buf_p++;
-
- /* Skip comment lines and empty lines. */
- if (*buf_p == '#' || *buf_p == '\0')
- return 0;
-
- /* Process the spec file entries */
- va_start(ap, num_args);
-
- items = 0;
- while (items < num_args) {
- spec_entry = va_arg(ap, char **);
-
- if (len - 1 == buf_p - line_buf) {
- va_end(ap);
- return items;
- }
+static int read_spec_entries(char* line_buf, int num_args, ...) {
+ char **spec_entry, *buf_p;
+ int len, rc, items, entry_len = 0;
+ va_list ap;
- rc = read_spec_entry(spec_entry, &buf_p, &entry_len);
- if (rc < 0) {
- va_end(ap);
- return rc;
- }
- if (entry_len)
- items++;
+ len = strlen(line_buf);
+ if (line_buf[len - 1] == '\n')
+ line_buf[len - 1] = '\0';
+ else
+ /* Handle case if line not \n terminated by bumping
+ * the len for the check below (as the line is NUL
+ * terminated by getline(3)) */
+ len++;
+
+ buf_p = line_buf;
+ while (isspace(*buf_p)) buf_p++;
+
+ /* Skip comment lines and empty lines. */
+ if (*buf_p == '#' || *buf_p == '\0') return 0;
+
+ /* Process the spec file entries */
+ va_start(ap, num_args);
+
+ items = 0;
+ while (items < num_args) {
+ spec_entry = va_arg(ap, char**);
+
+ if (len - 1 == buf_p - line_buf) {
+ va_end(ap);
+ return items;
}
- va_end(ap);
- return items;
-}
-static bool initialize_properties_from_file(const char *filename) {
- FILE* file = fopen(filename, "re");
- if (!file) {
- return false;
+ rc = read_spec_entry(spec_entry, &buf_p, &entry_len);
+ if (rc < 0) {
+ va_end(ap);
+ return rc;
}
+ if (entry_len) items++;
+ }
+ va_end(ap);
+ return items;
+}
- char* buffer = nullptr;
- size_t line_len;
- char* prop_prefix = nullptr;
- char* context = nullptr;
+static bool initialize_properties_from_file(const char* filename) {
+ FILE* file = fopen(filename, "re");
+ if (!file) {
+ return false;
+ }
- while (getline(&buffer, &line_len, file) > 0) {
- int items = read_spec_entries(buffer, 2, &prop_prefix, &context);
- if (items <= 0) {
- continue;
- }
- if (items == 1) {
- free(prop_prefix);
- continue;
- }
- /*
- * init uses ctl.* properties as an IPC mechanism and does not write them
- * to a property file, therefore we do not need to create property files
- * to store them.
- */
- if (!strncmp(prop_prefix, "ctl.", 4)) {
- free(prop_prefix);
- free(context);
- continue;
- }
+ char* buffer = nullptr;
+ size_t line_len;
+ char* prop_prefix = nullptr;
+ char* context = nullptr;
- auto old_context = list_find(
- contexts, [context](context_node* l) { return !strcmp(l->context(), context); });
- if (old_context) {
- list_add_after_len(&prefixes, prop_prefix, old_context);
- } else {
- list_add(&contexts, context, nullptr);
- list_add_after_len(&prefixes, prop_prefix, contexts);
- }
- free(prop_prefix);
- free(context);
+ while (getline(&buffer, &line_len, file) > 0) {
+ int items = read_spec_entries(buffer, 2, &prop_prefix, &context);
+ if (items <= 0) {
+ continue;
+ }
+ if (items == 1) {
+ free(prop_prefix);
+ continue;
+ }
+ /*
+ * init uses ctl.* properties as an IPC mechanism and does not write them
+ * to a property file, therefore we do not need to create property files
+ * to store them.
+ */
+ if (!strncmp(prop_prefix, "ctl.", 4)) {
+ free(prop_prefix);
+ free(context);
+ continue;
+ }
+
+ auto old_context =
+ list_find(contexts, [context](context_node* l) { return !strcmp(l->context(), context); });
+ if (old_context) {
+ list_add_after_len(&prefixes, prop_prefix, old_context);
+ } else {
+ list_add(&contexts, context, nullptr);
+ list_add_after_len(&prefixes, prop_prefix, contexts);
}
+ free(prop_prefix);
+ free(context);
+ }
- free(buffer);
- fclose(file);
+ free(buffer);
+ fclose(file);
- return true;
+ return true;
}
static bool initialize_properties() {
- // If we do find /property_contexts, then this is being
- // run as part of the OTA updater on older release that had
- // /property_contexts - b/34370523
- if (initialize_properties_from_file("/property_contexts")) {
- return true;
- }
+ // If we do find /property_contexts, then this is being
+ // run as part of the OTA updater on older release that had
+ // /property_contexts - b/34370523
+ if (initialize_properties_from_file("/property_contexts")) {
+ return true;
+ }
- // TODO: Change path to /system/property_contexts after b/27805372
+ // Use property_contexts from /system & /vendor, fall back to those from /
+ if (access("/system/etc/selinux/plat_property_contexts", R_OK) != -1) {
+ if (!initialize_properties_from_file("/system/etc/selinux/plat_property_contexts")) {
+ return false;
+ }
+ if (!initialize_properties_from_file("/vendor/etc/selinux/nonplat_property_contexts")) {
+ return false;
+ }
+ } else {
if (!initialize_properties_from_file("/plat_property_contexts")) {
- return false;
+ return false;
}
+ if (!initialize_properties_from_file("/nonplat_property_contexts")) {
+ return false;
+ }
+ }
- // TODO: Change path to /vendor/property_contexts after b/27805372
- // device-specific property context is optional, so load if it exists.
- initialize_properties_from_file("/nonplat_property_contexts");
-
- return true;
+ return true;
}
static bool is_dir(const char* pathname) {
- struct stat info;
- if (stat(pathname, &info) == -1) {
- return false;
- }
- return S_ISDIR(info.st_mode);
+ struct stat info;
+ if (stat(pathname, &info) == -1) {
+ return false;
+ }
+ return S_ISDIR(info.st_mode);
}
static void free_and_unmap_contexts() {
- list_free(&prefixes);
- list_free(&contexts);
- if (__system_property_area__) {
- munmap(__system_property_area__, pa_size);
- __system_property_area__ = nullptr;
- }
+ list_free(&prefixes);
+ list_free(&contexts);
+ if (__system_property_area__) {
+ munmap(__system_property_area__, pa_size);
+ __system_property_area__ = nullptr;
+ }
}
-int __system_properties_init()
-{
- if (initialized) {
- list_foreach(contexts, [](context_node* l) { l->reset_access(); });
- return 0;
+int __system_properties_init() {
+ // This is called from __libc_init_common, and should leave errno at 0 (http://b/37248982).
+ ErrnoRestorer errno_restorer;
+
+ if (initialized) {
+ list_foreach(contexts, [](context_node* l) { l->reset_access(); });
+ return 0;
+ }
+ if (is_dir(property_filename)) {
+ if (!initialize_properties()) {
+ return -1;
}
- if (is_dir(property_filename)) {
- if (!initialize_properties()) {
- return -1;
- }
- if (!map_system_property_area(false, nullptr)) {
- free_and_unmap_contexts();
- return -1;
- }
- } else {
- __system_property_area__ = map_prop_area(property_filename);
- if (!__system_property_area__) {
- return -1;
- }
- list_add(&contexts, "legacy_system_prop_area", __system_property_area__);
- list_add_after_len(&prefixes, "*", contexts);
+ if (!map_system_property_area(false, nullptr)) {
+ free_and_unmap_contexts();
+ return -1;
}
- initialized = true;
- return 0;
+ } else {
+ __system_property_area__ = map_prop_area(property_filename);
+ if (!__system_property_area__) {
+ return -1;
+ }
+ list_add(&contexts, "legacy_system_prop_area", __system_property_area__);
+ list_add_after_len(&prefixes, "*", contexts);
+ }
+ initialized = true;
+ return 0;
}
-int __system_property_set_filename(const char *filename)
-{
- size_t len = strlen(filename);
- if (len >= sizeof(property_filename))
- return -1;
+int __system_property_set_filename(const char* filename) {
+ size_t len = strlen(filename);
+ if (len >= sizeof(property_filename)) return -1;
- strcpy(property_filename, filename);
- return 0;
+ strcpy(property_filename, filename);
+ return 0;
}
-int __system_property_area_init()
-{
+int __system_property_area_init() {
+ free_and_unmap_contexts();
+ mkdir(property_filename, S_IRWXU | S_IXGRP | S_IXOTH);
+ if (!initialize_properties()) {
+ return -1;
+ }
+ bool open_failed = false;
+ bool fsetxattr_failed = false;
+ list_foreach(contexts, [&fsetxattr_failed, &open_failed](context_node* l) {
+ if (!l->open(true, &fsetxattr_failed)) {
+ open_failed = true;
+ }
+ });
+ if (open_failed || !map_system_property_area(true, &fsetxattr_failed)) {
free_and_unmap_contexts();
- mkdir(property_filename, S_IRWXU | S_IXGRP | S_IXOTH);
- if (!initialize_properties()) {
- return -1;
- }
- bool open_failed = false;
- bool fsetxattr_failed = false;
- list_foreach(contexts, [&fsetxattr_failed, &open_failed](context_node* l) {
- if (!l->open(true, &fsetxattr_failed)) {
- open_failed = true;
- }
- });
- if (open_failed || !map_system_property_area(true, &fsetxattr_failed)) {
- free_and_unmap_contexts();
- return -1;
- }
- initialized = true;
- return fsetxattr_failed ? -2 : 0;
+ return -1;
+ }
+ initialized = true;
+ return fsetxattr_failed ? -2 : 0;
}
-unsigned int __system_property_area_serial()
-{
- prop_area *pa = __system_property_area__;
- if (!pa) {
- return -1;
- }
- // Make sure this read fulfilled before __system_property_serial
- return atomic_load_explicit(pa->serial(), memory_order_acquire);
+uint32_t __system_property_area_serial() {
+ prop_area* pa = __system_property_area__;
+ if (!pa) {
+ return -1;
+ }
+ // Make sure this read fulfilled before __system_property_serial
+ return atomic_load_explicit(pa->serial(), memory_order_acquire);
}
-const prop_info *__system_property_find(const char *name)
-{
- if (!__system_property_area__) {
- return nullptr;
- }
+const prop_info* __system_property_find(const char* name) {
+ if (!__system_property_area__) {
+ return nullptr;
+ }
- prop_area* pa = get_prop_area_for_name(name);
- if (!pa) {
- __libc_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
- return nullptr;
- }
+ prop_area* pa = get_prop_area_for_name(name);
+ if (!pa) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
+ return nullptr;
+ }
- return pa->find(name);
+ return pa->find(name);
}
// The C11 standard doesn't allow atomic loads from const fields,
// though C++11 does. Fudge it until standards get straightened out.
-static inline uint_least32_t load_const_atomic(const atomic_uint_least32_t* s,
- memory_order mo) {
- atomic_uint_least32_t* non_const_s = const_cast<atomic_uint_least32_t*>(s);
- return atomic_load_explicit(non_const_s, mo);
+static inline uint_least32_t load_const_atomic(const atomic_uint_least32_t* s, memory_order mo) {
+ atomic_uint_least32_t* non_const_s = const_cast<atomic_uint_least32_t*>(s);
+ return atomic_load_explicit(non_const_s, mo);
}
-int __system_property_read(const prop_info *pi, char *name, char *value) {
- while (true) {
- uint32_t serial = __system_property_serial(pi); // acquire semantics
- size_t len = SERIAL_VALUE_LEN(serial);
- memcpy(value, pi->value, len + 1);
- // TODO: Fix the synchronization scheme here.
- // There is no fully supported way to implement this kind
- // of synchronization in C++11, since the memcpy races with
- // updates to pi, and the data being accessed is not atomic.
- // The following fence is unintuitive, but would be the
- // correct one if memcpy used memory_order_relaxed atomic accesses.
- // In practice it seems unlikely that the generated code would
- // would be any different, so this should be OK.
- atomic_thread_fence(memory_order_acquire);
- if (serial ==
- load_const_atomic(&(pi->serial), memory_order_relaxed)) {
- if (name != nullptr) {
- size_t namelen = strlcpy(name, pi->name, PROP_NAME_MAX);
- if(namelen >= PROP_NAME_MAX) {
- __libc_format_log(ANDROID_LOG_ERROR, "libc",
- "The property name length for \"%s\" is >= %d;"
- " please use __system_property_read_callback"
- " to read this property. (the name is truncated to \"%s\")",
- pi->name, PROP_NAME_MAX - 1, name);
- }
- }
- return len;
+int __system_property_read(const prop_info* pi, char* name, char* value) {
+ while (true) {
+ uint32_t serial = __system_property_serial(pi); // acquire semantics
+ size_t len = SERIAL_VALUE_LEN(serial);
+ memcpy(value, pi->value, len + 1);
+ // TODO: Fix the synchronization scheme here.
+ // There is no fully supported way to implement this kind
+ // of synchronization in C++11, since the memcpy races with
+ // updates to pi, and the data being accessed is not atomic.
+ // The following fence is unintuitive, but would be the
+ // correct one if memcpy used memory_order_relaxed atomic accesses.
+ // In practice it seems unlikely that the generated code would
+ // would be any different, so this should be OK.
+ atomic_thread_fence(memory_order_acquire);
+ if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
+ if (name != nullptr) {
+ size_t namelen = strlcpy(name, pi->name, PROP_NAME_MAX);
+ if (namelen >= PROP_NAME_MAX) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+ "The property name length for \"%s\" is >= %d;"
+ " please use __system_property_read_callback"
+ " to read this property. (the name is truncated to \"%s\")",
+ pi->name, PROP_NAME_MAX - 1, name);
}
+ }
+ return len;
}
+ }
}
void __system_property_read_callback(const prop_info* pi,
- void (*callback)(void* cookie, const char* name, const char* value),
+ void (*callback)(void* cookie,
+ const char* name,
+ const char* value,
+ uint32_t serial),
void* cookie) {
while (true) {
- uint32_t serial = __system_property_serial(pi); // acquire semantics
+ uint32_t serial = __system_property_serial(pi); // acquire semantics
size_t len = SERIAL_VALUE_LEN(serial);
- char value_buf[len+1];
+ char value_buf[len + 1];
memcpy(value_buf, pi->value, len);
value_buf[len] = '\0';
// TODO: see todo in __system_property_read function
atomic_thread_fence(memory_order_acquire);
if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
- callback(cookie, pi->name, value_buf);
+ callback(cookie, pi->name, value_buf, serial);
return;
}
}
}
-int __system_property_get(const char *name, char *value)
-{
- const prop_info *pi = __system_property_find(name);
+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, nullptr, value);
- } else {
- value[0] = 0;
- return 0;
- }
+ if (pi != 0) {
+ return __system_property_read(pi, nullptr, value);
+ } else {
+ value[0] = 0;
+ return 0;
+ }
}
static constexpr uint32_t kProtocolVersion1 = 1;
-static constexpr uint32_t kProtocolVersion2 = 2; // current
+static constexpr uint32_t kProtocolVersion2 = 2; // current
static atomic_uint_least32_t g_propservice_protocol_version = 0;
static void detect_protocol_version() {
- char value[PROP_VALUE_MAX];
- if (__system_property_get(kServiceVersionPropertyName, value) == 0) {
- g_propservice_protocol_version = kProtocolVersion1;
- __libc_format_log(ANDROID_LOG_WARN, "libc",
+ char value[PROP_VALUE_MAX];
+ if (__system_property_get(kServiceVersionPropertyName, value) == 0) {
+ g_propservice_protocol_version = kProtocolVersion1;
+ async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Using old property service protocol (\"%s\" is not set)",
kServiceVersionPropertyName);
+ } else {
+ uint32_t version = static_cast<uint32_t>(atoll(value));
+ if (version >= kProtocolVersion2) {
+ g_propservice_protocol_version = kProtocolVersion2;
} else {
- uint32_t version = static_cast<uint32_t>(atoll(value));
- if (version >= kProtocolVersion2) {
- g_propservice_protocol_version = kProtocolVersion2;
- } else {
- __libc_format_log(ANDROID_LOG_WARN, "libc",
+ async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Using old property service protocol (\"%s\"=\"%s\")",
kServiceVersionPropertyName, value);
- g_propservice_protocol_version = kProtocolVersion1;
- }
+ g_propservice_protocol_version = kProtocolVersion1;
}
+ }
}
int __system_property_set(const char* key, const char* value) {
- if (key == nullptr) return -1;
- if (value == nullptr) value = "";
- if (strlen(value) >= PROP_VALUE_MAX) return -1;
+ if (key == nullptr) return -1;
+ if (value == nullptr) value = "";
+ if (strlen(value) >= PROP_VALUE_MAX) return -1;
- if (g_propservice_protocol_version == 0) {
- detect_protocol_version();
- }
+ if (g_propservice_protocol_version == 0) {
+ detect_protocol_version();
+ }
- int result = -1;
- if (g_propservice_protocol_version == kProtocolVersion1) {
- // Old protocol does not support long names
- if (strlen(key) >= PROP_NAME_MAX) return -1;
+ if (g_propservice_protocol_version == kProtocolVersion1) {
+ // Old protocol does not support long names
+ if (strlen(key) >= PROP_NAME_MAX) return -1;
- prop_msg msg;
- memset(&msg, 0, sizeof msg);
- msg.cmd = PROP_MSG_SETPROP;
- strlcpy(msg.name, key, sizeof msg.name);
- strlcpy(msg.value, value, sizeof msg.value);
+ prop_msg msg;
+ memset(&msg, 0, sizeof msg);
+ msg.cmd = PROP_MSG_SETPROP;
+ strlcpy(msg.name, key, sizeof msg.name);
+ strlcpy(msg.value, value, sizeof msg.value);
- result = send_prop_msg(&msg);
- } else {
- // Use proper protocol
- PropertyServiceConnection connection;
- if (connection.IsValid() &&
- connection.SendUint32(PROP_MSG_SETPROP2) &&
- connection.SendString(key) &&
- connection.SendString(value) &&
- connection.RecvInt32(&result)) {
- if (result != PROP_SUCCESS) {
- __libc_format_log(ANDROID_LOG_WARN, "libc",
- "Unable to set property \"%s\" to \"%s\": error code: 0x%x",
- key, value, result);
- }
- } else {
- result = connection.GetLastError();
- __libc_format_log(ANDROID_LOG_WARN, "libc",
- "Unable to set property \"%s\" to \"%s\": error code: 0x%x (%s)",
- key, value, result, strerror(result));
- }
+ return send_prop_msg(&msg);
+ } else {
+ // Use proper protocol
+ PropertyServiceConnection connection;
+ if (!connection.IsValid()) {
+ errno = connection.GetLastError();
+ async_safe_format_log(ANDROID_LOG_WARN,
+ "libc",
+ "Unable to set property \"%s\" to \"%s\": connection failed; errno=%d (%s)",
+ key,
+ value,
+ errno,
+ strerror(errno));
+ return -1;
+ }
+
+ SocketWriter writer(&connection);
+ if (!writer.WriteUint32(PROP_MSG_SETPROP2).WriteString(key).WriteString(value).Send()) {
+ errno = connection.GetLastError();
+ async_safe_format_log(ANDROID_LOG_WARN,
+ "libc",
+ "Unable to set property \"%s\" to \"%s\": write failed; errno=%d (%s)",
+ key,
+ value,
+ errno,
+ strerror(errno));
+ return -1;
+ }
+
+ int result = -1;
+ if (!connection.RecvInt32(&result)) {
+ errno = connection.GetLastError();
+ async_safe_format_log(ANDROID_LOG_WARN,
+ "libc",
+ "Unable to set property \"%s\" to \"%s\": recv failed; errno=%d (%s)",
+ key,
+ value,
+ errno,
+ strerror(errno));
+ return -1;
+ }
+
+ if (result != PROP_SUCCESS) {
+ async_safe_format_log(ANDROID_LOG_WARN,
+ "libc",
+ "Unable to set property \"%s\" to \"%s\": error code: 0x%x",
+ key,
+ value,
+ result);
+ return -1;
}
- return result != 0 ? -1 : 0;
+ return 0;
+ }
}
-int __system_property_update(prop_info *pi, const char *value, unsigned int len)
-{
- if (len >= PROP_VALUE_MAX) {
- return -1;
- }
+int __system_property_update(prop_info* pi, const char* value, unsigned int len) {
+ if (len >= PROP_VALUE_MAX) {
+ return -1;
+ }
- prop_area* pa = __system_property_area__;
+ prop_area* pa = __system_property_area__;
- if (!pa) {
- return -1;
- }
+ if (!pa) {
+ return -1;
+ }
- uint32_t serial = atomic_load_explicit(&pi->serial, memory_order_relaxed);
- serial |= 1;
- atomic_store_explicit(&pi->serial, serial, memory_order_relaxed);
- // The memcpy call here also races. Again pretend it
- // used memory_order_relaxed atomics, and use the analogous
- // counterintuitive fence.
- atomic_thread_fence(memory_order_release);
- strlcpy(pi->value, value, len + 1);
-
- atomic_store_explicit(
- &pi->serial,
- (len << 24) | ((serial + 1) & 0xffffff),
- memory_order_release);
- __futex_wake(&pi->serial, INT32_MAX);
-
- atomic_store_explicit(
- pa->serial(),
- atomic_load_explicit(pa->serial(), memory_order_relaxed) + 1,
- memory_order_release);
- __futex_wake(pa->serial(), INT32_MAX);
+ uint32_t serial = atomic_load_explicit(&pi->serial, memory_order_relaxed);
+ serial |= 1;
+ atomic_store_explicit(&pi->serial, serial, memory_order_relaxed);
+ // The memcpy call here also races. Again pretend it
+ // used memory_order_relaxed atomics, and use the analogous
+ // counterintuitive fence.
+ atomic_thread_fence(memory_order_release);
+ strlcpy(pi->value, value, len + 1);
- return 0;
+ atomic_store_explicit(&pi->serial, (len << 24) | ((serial + 1) & 0xffffff), memory_order_release);
+ __futex_wake(&pi->serial, INT32_MAX);
+
+ atomic_store_explicit(pa->serial(), atomic_load_explicit(pa->serial(), memory_order_relaxed) + 1,
+ memory_order_release);
+ __futex_wake(pa->serial(), INT32_MAX);
+
+ return 0;
}
-int __system_property_add(const char *name, unsigned int namelen,
- const char *value, unsigned int valuelen)
-{
- if (valuelen >= PROP_VALUE_MAX) {
- return -1;
- }
+int __system_property_add(const char* name, unsigned int namelen, const char* value,
+ unsigned int valuelen) {
+ if (valuelen >= PROP_VALUE_MAX) {
+ return -1;
+ }
- if (namelen < 1) {
- return -1;
- }
+ if (namelen < 1) {
+ return -1;
+ }
- if (!__system_property_area__) {
- return -1;
- }
+ if (!__system_property_area__) {
+ return -1;
+ }
- prop_area* pa = get_prop_area_for_name(name);
+ prop_area* pa = get_prop_area_for_name(name);
- if (!pa) {
- __libc_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
- return -1;
- }
+ if (!pa) {
+ async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
+ return -1;
+ }
- bool ret = pa->add(name, namelen, value, valuelen);
- if (!ret) {
- return -1;
- }
+ bool ret = pa->add(name, namelen, value, valuelen);
+ if (!ret) {
+ return -1;
+ }
- // There is only a single mutator, but we want to make sure that
- // updates are visible to a reader waiting for the update.
- atomic_store_explicit(
- __system_property_area__->serial(),
- atomic_load_explicit(__system_property_area__->serial(), memory_order_relaxed) + 1,
- memory_order_release);
- __futex_wake(__system_property_area__->serial(), INT32_MAX);
- return 0;
+ // There is only a single mutator, but we want to make sure that
+ // updates are visible to a reader waiting for the update.
+ atomic_store_explicit(
+ __system_property_area__->serial(),
+ atomic_load_explicit(__system_property_area__->serial(), memory_order_relaxed) + 1,
+ memory_order_release);
+ __futex_wake(__system_property_area__->serial(), INT32_MAX);
+ return 0;
}
// Wait for non-locked serial, and retrieve it with acquire semantics.
-unsigned int __system_property_serial(const prop_info *pi)
-{
- uint32_t serial = load_const_atomic(&pi->serial, memory_order_acquire);
- while (SERIAL_DIRTY(serial)) {
- __futex_wait(const_cast<volatile void *>(
- reinterpret_cast<const void *>(&pi->serial)),
- serial, NULL);
- serial = load_const_atomic(&pi->serial, memory_order_acquire);
- }
- return serial;
+uint32_t __system_property_serial(const prop_info* pi) {
+ uint32_t serial = load_const_atomic(&pi->serial, memory_order_acquire);
+ while (SERIAL_DIRTY(serial)) {
+ __futex_wait(const_cast<_Atomic(uint_least32_t)*>(&pi->serial), serial, nullptr);
+ serial = load_const_atomic(&pi->serial, memory_order_acquire);
+ }
+ return serial;
}
-unsigned int __system_property_wait_any(unsigned int serial)
-{
- prop_area *pa = __system_property_area__;
- uint32_t my_serial;
+uint32_t __system_property_wait_any(uint32_t old_serial) {
+ uint32_t new_serial;
+ __system_property_wait(nullptr, old_serial, &new_serial, nullptr);
+ return new_serial;
+}
- if (!pa) {
- return 0;
- }
+bool __system_property_wait(const prop_info* pi,
+ uint32_t old_serial,
+ uint32_t* new_serial_ptr,
+ const timespec* relative_timeout) {
+ // Are we waiting on the global serial or a specific serial?
+ atomic_uint_least32_t* serial_ptr;
+ if (pi == nullptr) {
+ if (__system_property_area__ == nullptr) return -1;
+ serial_ptr = __system_property_area__->serial();
+ } else {
+ serial_ptr = const_cast<atomic_uint_least32_t*>(&pi->serial);
+ }
- do {
- __futex_wait(pa->serial(), serial, NULL);
- my_serial = atomic_load_explicit(pa->serial(), memory_order_acquire);
- } while (my_serial == serial);
+ uint32_t new_serial;
+ do {
+ int rc;
+ if ((rc = __futex_wait(serial_ptr, old_serial, relative_timeout)) != 0 && rc == -ETIMEDOUT) {
+ return false;
+ }
+ new_serial = load_const_atomic(serial_ptr, memory_order_acquire);
+ } while (new_serial == old_serial);
- return my_serial;
+ *new_serial_ptr = new_serial;
+ return true;
}
-const prop_info *__system_property_find_nth(unsigned n)
-{
- if (bionic_get_application_target_sdk_version() >= __ANDROID_API_O__) {
- __libc_fatal("__system_property_find_nth is not supported since Android O,"
- " please use __system_property_foreach instead.");
- }
-
- find_nth_cookie cookie(n);
+const prop_info* __system_property_find_nth(unsigned n) {
+ struct find_nth {
+ const uint32_t sought;
+ uint32_t current;
+ const prop_info* result;
- const int err = __system_property_foreach(find_nth_fn, &cookie);
- if (err < 0) {
- return NULL;
+ explicit find_nth(uint32_t n) : sought(n), current(0), result(nullptr) {}
+ static void fn(const prop_info* pi, void* ptr) {
+ find_nth* self = reinterpret_cast<find_nth*>(ptr);
+ if (self->current++ == self->sought) self->result = pi;
}
-
- return cookie.pi;
+ } state(n);
+ __system_property_foreach(find_nth::fn, &state);
+ return state.result;
}
-int __system_property_foreach(void (*propfn)(const prop_info *pi, void *cookie), void *cookie)
-{
- if (!__system_property_area__) {
- return -1;
- }
+int __system_property_foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
+ if (!__system_property_area__) {
+ return -1;
+ }
- list_foreach(contexts, [propfn, cookie](context_node* l) {
- if (l->check_access_and_open()) {
- l->pa()->foreach(propfn, cookie);
- }
- });
- return 0;
+ list_foreach(contexts, [propfn, cookie](context_node* l) {
+ if (l->check_access_and_open()) {
+ l->pa()->foreach(propfn, cookie);
+ }
+ });
+ return 0;
}
OSDN Git Service
