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authorMathieu Chartier <mathieuc@google.com>2014-06-03 19:02:35 +0000
committerGerrit Code Review <noreply-gerritcodereview@google.com>2014-06-03 19:02:35 +0000
commit03b87b49fae82a6304ab69b10426701c4f82c7e9 (patch)
treec496707cd5f73d640921e787877774f5f643bd93 /libcutils
parentb0b343d0864556816d89af61f7418130cea047d0 (diff)
parent1104ae8cfc0e5144e7d796cf29ee124d05401cbf (diff)
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Merge "Make host ashmem_create_region seed only once."
Diffstat (limited to 'libcutils')
-rw-r--r--libcutils/ashmem-host.c124
1 files changed, 63 insertions, 61 deletions
diff --git a/libcutils/ashmem-host.c b/libcutils/ashmem-host.c
index 7873964..4ac4f57 100644
--- a/libcutils/ashmem-host.c
+++ b/libcutils/ashmem-host.c
@@ -22,6 +22,8 @@
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
+#include <pthread.h>
+#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -36,83 +38,83 @@
#define __unused __attribute__((__unused__))
#endif
+static pthread_once_t seed_initialized = PTHREAD_ONCE_INIT;
+static void initialize_random() {
+ srand(time(NULL) + getpid());
+}
+
int ashmem_create_region(const char *ignored __unused, size_t size)
{
- static const char txt[] = "abcdefghijklmnopqrstuvwxyz"
- "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
- char name[64];
- unsigned int retries = 0;
- pid_t pid = getpid();
- int fd;
-
- srand(time(NULL) + pid);
-
-retry:
- /* not beautiful, its just wolf-like loop unrolling */
- snprintf(name, sizeof(name), "/tmp/android-ashmem-%d-%c%c%c%c%c%c%c%c",
- pid,
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
- txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))]);
-
- /* open O_EXCL & O_CREAT: we are either the sole owner or we fail */
- fd = open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
- if (fd == -1) {
- /* unlikely, but if we failed because `name' exists, retry */
- if (errno == EEXIST && ++retries < 6)
- goto retry;
- return -1;
- }
-
- /* truncate the file to `len' bytes */
- if (ftruncate(fd, size) == -1)
- goto error;
-
- if (unlink(name) == -1)
- goto error;
-
- return fd;
-error:
- close(fd);
- return -1;
+ static const char txt[] = "abcdefghijklmnopqrstuvwxyz"
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+ char name[64];
+ unsigned int retries = 0;
+ pid_t pid = getpid();
+ int fd;
+ if (pthread_once(&seed_initialized, &initialize_random) != 0) {
+ return -1;
+ }
+ do {
+ /* not beautiful, its just wolf-like loop unrolling */
+ snprintf(name, sizeof(name), "/tmp/android-ashmem-%d-%c%c%c%c%c%c%c%c",
+ pid,
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))],
+ txt[(int) ((sizeof(txt) - 1) * (rand() / (RAND_MAX + 1.0)))]);
+
+ /* open O_EXCL & O_CREAT: we are either the sole owner or we fail */
+ fd = open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
+ if (fd == -1) {
+ /* unlikely, but if we failed because `name' exists, retry */
+ if (errno != EEXIST || ++retries >= 6) {
+ return -1;
+ }
+ }
+ } while (fd == -1);
+ /* truncate the file to `len' bytes */
+ if (ftruncate(fd, size) != -1 && unlink(name) != -1) {
+ return fd;
+ }
+ close(fd);
+ return -1;
}
int ashmem_set_prot_region(int fd __unused, int prot __unused)
{
- return 0;
+ return 0;
}
int ashmem_pin_region(int fd __unused, size_t offset __unused, size_t len __unused)
{
- return ASHMEM_NOT_PURGED;
+ return ASHMEM_NOT_PURGED;
}
int ashmem_unpin_region(int fd __unused, size_t offset __unused, size_t len __unused)
{
- return ASHMEM_IS_UNPINNED;
+ return ASHMEM_IS_UNPINNED;
}
int ashmem_get_size_region(int fd)
{
- struct stat buf;
- int result;
-
- result = fstat(fd, &buf);
- if (result == -1) {
- return -1;
- }
-
- // Check if this is an "ashmem" region.
- // TODO: This is very hacky, and can easily break. We need some reliable indicator.
- if (!(buf.st_nlink == 0 && S_ISREG(buf.st_mode))) {
- errno = ENOTTY;
- return -1;
- }
-
- return (int)buf.st_size; // TODO: care about overflow (> 2GB file)?
+ struct stat buf;
+ int result;
+
+ result = fstat(fd, &buf);
+ if (result == -1) {
+ return -1;
+ }
+
+ // Check if this is an "ashmem" region.
+ // TODO: This is very hacky, and can easily break. We need some reliable indicator.
+ if (!(buf.st_nlink == 0 && S_ISREG(buf.st_mode))) {
+ errno = ENOTTY;
+ return -1;
+ }
+
+ return (int)buf.st_size; // TODO: care about overflow (> 2GB file)?
}