libcutils: clean up the ashmem code a bit.
Less duplication, more modern idioms.
Change-Id: Ic6f36a35abf0c8b99f23ec9d59d76a4fd6b091ca
diff --git a/libcutils/ashmem-dev.cpp b/libcutils/ashmem-dev.cpp
index 768db81..b4f1d7f 100644
--- a/libcutils/ashmem-dev.cpp
+++ b/libcutils/ashmem-dev.cpp
@@ -76,8 +76,8 @@
* debugging.
*/
-static bool debug_log = false; /* set to true for verbose logging and other debug */
-static bool pin_deprecation_warn = true; /* Log the pin deprecation warning only once */
+/* set to true for verbose logging and other debug */
+static bool debug_log = false;
/* Determine if vendor processes would be ok with memfd in the system:
*
@@ -120,11 +120,9 @@
// permissions of the buffer (i.e. they cannot be changed by fchmod()).
//
// MFD_NOEXEC_SEAL implies MFD_ALLOW_SEALING.
- const char *test_buf_name = "test_android_memfd";
- size_t buf_size = getpagesize();
android::base::unique_fd fd(
- syscall(__NR_memfd_create, test_buf_name, MFD_CLOEXEC | MFD_NOEXEC_SEAL));
+ syscall(__NR_memfd_create, "test_android_memfd", MFD_CLOEXEC | MFD_NOEXEC_SEAL));
if (fd == -1) {
ALOGE("memfd_create failed: %m, no memfd support");
return false;
@@ -135,9 +133,9 @@
return false;
}
+ size_t buf_size = getpagesize();
if (ftruncate(fd, buf_size) == -1) {
- ALOGE("ftruncate(%s, %zd) failed to set memfd buffer size: %m, no memfd support",
- test_buf_name, buf_size);
+ ALOGE("ftruncate(%zd) failed to set memfd buffer size: %m, no memfd support", buf_size);
return false;
}
@@ -159,11 +157,7 @@
}
static bool has_memfd_support() {
- /* memfd_supported is the initial global per-process state of what is known
- * about memfd.
- */
static bool memfd_supported = __has_memfd_support();
-
return memfd_supported;
}
@@ -173,75 +167,64 @@
if (!android::base::ReadFileToString(boot_id_path, &boot_id)) {
ALOGE("Failed to read %s: %m", boot_id_path.c_str());
return "";
- };
+ }
boot_id = android::base::Trim(boot_id);
return "/dev/ashmem" + boot_id;
}
/* logistics of getting file descriptor for ashmem */
-static int __ashmem_open_locked()
-{
+static int __ashmem_open_locked() {
static const std::string ashmem_device_path = get_ashmem_device_path();
if (ashmem_device_path.empty()) {
return -1;
}
- int fd = TEMP_FAILURE_RETRY(open(ashmem_device_path.c_str(), O_RDWR | O_CLOEXEC));
-
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(ashmem_device_path.c_str(), O_RDWR | O_CLOEXEC)));
+ int errno1 = errno;
// fallback for APEX w/ use_vendor on Q, which would have still used /dev/ashmem
- if (fd < 0) {
- int saved_errno = errno;
- fd = TEMP_FAILURE_RETRY(open("/dev/ashmem", O_RDWR | O_CLOEXEC));
- if (fd < 0) {
+ // TODO: remove this?
+ if (!fd.ok()) {
+ fd.reset(TEMP_FAILURE_RETRY(open("/dev/ashmem", O_RDWR | O_CLOEXEC)));
+ int errno2 = errno;
+ if (!fd.ok()) {
/* Q launching devices and newer must not reach here since they should have been
* able to open ashmem_device_path */
- ALOGE("Unable to open ashmem device %s (error = %s) and /dev/ashmem(error = %s)",
- ashmem_device_path.c_str(), strerror(saved_errno), strerror(errno));
- return fd;
+ ALOGE("Unable to open ashmem device %s (%s) and /dev/ashmem (%s)",
+ ashmem_device_path.c_str(), strerror(errno1), strerror(errno2));
+ return -1;
}
}
+
struct stat st;
- int ret = TEMP_FAILURE_RETRY(fstat(fd, &st));
- if (ret < 0) {
- int save_errno = errno;
- close(fd);
- errno = save_errno;
- return ret;
+ if (TEMP_FAILURE_RETRY(fstat(fd, &st)) == -1) {
+ return -1;
}
if (!S_ISCHR(st.st_mode) || !st.st_rdev) {
- close(fd);
errno = ENOTTY;
return -1;
}
__ashmem_rdev = st.st_rdev;
- return fd;
+ return fd.release();
}
-static int __ashmem_open()
-{
- int fd;
-
+static int __ashmem_open() {
pthread_mutex_lock(&__ashmem_lock);
- fd = __ashmem_open_locked();
+ int fd = __ashmem_open_locked();
pthread_mutex_unlock(&__ashmem_lock);
-
return fd;
}
/* Make sure file descriptor references ashmem, negative number means false */
-static int __ashmem_is_ashmem(int fd, int fatal)
-{
- dev_t rdev;
+static int __ashmem_is_ashmem(int fd, bool fatal) {
struct stat st;
-
if (fstat(fd, &st) < 0) {
return -1;
}
- rdev = 0; /* Too much complexity to sniff __ashmem_rdev */
+ dev_t rdev = 0; /* Too much complexity to sniff __ashmem_rdev */
if (S_ISCHR(st.st_mode) && st.st_rdev) {
pthread_mutex_lock(&__ashmem_lock);
rdev = __ashmem_rdev;
@@ -282,16 +265,15 @@
return -1;
}
-static int __ashmem_check_failure(int fd, int result)
-{
- if (result == -1 && errno == ENOTTY) __ashmem_is_ashmem(fd, 1);
+static int __ashmem_check_failure(int fd, int result) {
+ if (result == -1 && errno == ENOTTY) __ashmem_is_ashmem(fd, true);
return result;
}
-static bool memfd_is_ashmem(int fd) {
+static bool is_ashmem_fd(int fd) {
static bool fd_check_error_once = false;
- if (__ashmem_is_ashmem(fd, 0) == 0) {
+ if (__ashmem_is_ashmem(fd, false) == 0) {
if (!fd_check_error_once) {
ALOGE("memfd: memfd expected but ashmem fd used - please use libcutils");
fd_check_error_once = true;
@@ -303,13 +285,16 @@
return false;
}
-int ashmem_valid(int fd)
-{
- if (has_memfd_support() && !memfd_is_ashmem(fd)) {
+static bool is_memfd_fd(int fd) {
+ return has_memfd_support() && !is_ashmem_fd(fd);
+}
+
+int ashmem_valid(int fd) {
+ if (is_memfd_fd(fd)) {
return 1;
}
- return __ashmem_is_ashmem(fd, 0) >= 0;
+ return __ashmem_is_ashmem(fd, false) >= 0;
}
static int memfd_create_region(const char* name, size_t size) {
@@ -352,41 +337,20 @@
* `name' is an optional label to give the region (visible in /proc/pid/maps)
* `size' is the size of the region, in page-aligned bytes
*/
-int ashmem_create_region(const char *name, size_t size)
-{
- int ret, save_errno;
+int ashmem_create_region(const char* name, size_t size) {
+ if (name == NULL) name = "none";
if (has_memfd_support()) {
- return memfd_create_region(name ? name : "none", size);
+ return memfd_create_region(name, size);
}
- int fd = __ashmem_open();
- if (fd < 0) {
- return fd;
+ android::base::unique_fd fd(__ashmem_open());
+ if (!fd.ok() ||
+ TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_NAME, name) < 0) ||
+ TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_SIZE, size) < 0)) {
+ return -1;
}
-
- if (name) {
- char buf[ASHMEM_NAME_LEN] = {0};
-
- strlcpy(buf, name, sizeof(buf));
- ret = TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_NAME, buf));
- if (ret < 0) {
- goto error;
- }
- }
-
- ret = TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_SIZE, size));
- if (ret < 0) {
- goto error;
- }
-
- return fd;
-
-error:
- save_errno = errno;
- close(fd);
- errno = save_errno;
- return ret;
+ return fd.release();
}
static int memfd_set_prot_region(int fd, int prot) {
@@ -418,61 +382,45 @@
return 0;
}
-int ashmem_set_prot_region(int fd, int prot)
-{
- if (has_memfd_support() && !memfd_is_ashmem(fd)) {
+int ashmem_set_prot_region(int fd, int prot) {
+ if (is_memfd_fd(fd)) {
return memfd_set_prot_region(fd, prot);
}
return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_SET_PROT_MASK, prot)));
}
-int ashmem_pin_region(int fd, size_t offset, size_t len)
-{
- if (!pin_deprecation_warn || debug_log) {
+static int do_pin(int op, int fd, size_t offset, size_t length) {
+ static bool already_warned_about_pin_deprecation = false;
+ if (!already_warned_about_pin_deprecation || debug_log) {
ALOGE("Pinning is deprecated since Android Q. Please use trim or other methods.");
- pin_deprecation_warn = true;
+ already_warned_about_pin_deprecation = true;
}
- if (has_memfd_support() && !memfd_is_ashmem(fd)) {
+ if (is_memfd_fd(fd)) {
return 0;
}
// TODO: should LP64 reject too-large offset/len?
- ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(len) };
- return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_PIN, &pin)));
+ ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(length) };
+ return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, op, &pin)));
}
-int ashmem_unpin_region(int fd, size_t offset, size_t len)
-{
- if (!pin_deprecation_warn || debug_log) {
- ALOGE("Pinning is deprecated since Android Q. Please use trim or other methods.");
- pin_deprecation_warn = true;
- }
-
- if (has_memfd_support() && !memfd_is_ashmem(fd)) {
- return 0;
- }
-
- // TODO: should LP64 reject too-large offset/len?
- ashmem_pin pin = { static_cast<uint32_t>(offset), static_cast<uint32_t>(len) };
- return __ashmem_check_failure(fd, TEMP_FAILURE_RETRY(ioctl(fd, ASHMEM_UNPIN, &pin)));
+int ashmem_pin_region(int fd, size_t offset, size_t length) {
+ return do_pin(ASHMEM_PIN, fd, offset, length);
}
-int ashmem_get_size_region(int fd)
-{
- if (has_memfd_support() && !memfd_is_ashmem(fd)) {
+int ashmem_unpin_region(int fd, size_t offset, size_t length) {
+ return do_pin(ASHMEM_UNPIN, fd, offset, length);
+}
+
+int ashmem_get_size_region(int fd) {
+ if (is_memfd_fd(fd)) {
struct stat sb;
-
if (fstat(fd, &sb) == -1) {
ALOGE("ashmem_get_size_region(%d): fstat failed: %m", fd);
return -1;
}
-
- if (debug_log) {
- ALOGD("ashmem_get_size_region(%d): %d", fd, static_cast<int>(sb.st_size));
- }
-
return sb.st_size;
}