Merge "Use mkstemp for host ashmem." (3bc8ae63) · Commits · e / os / android_system_core

libcutils/ashmem-host.c

+7 −43

Original line number	Diff line number	Diff line
		@@ -22,7 +22,6 @@
		#include <errno.h>
		#include <fcntl.h>
		#include <limits.h>
		#include <pthread.h>
		#include <stdbool.h>
		#include <stdio.h>
		#include <stdlib.h>
		@@ -33,51 +32,18 @@
		#include <unistd.h>

		#include <cutils/ashmem.h>
		#include <utils/Compat.h>

		#ifndef __unused
		#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;
		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) {
		char template[PATH_MAX];
		snprintf(template, sizeof(template), "/tmp/android-ashmem-%d-XXXXXXXXX", getpid());
		int fd = mkstemp(template);
		if (fd != -1 && TEMP_FAILURE_RETRY(ftruncate(fd, size)) != -1 && unlink(template) != -1) {
		return fd;
		}
		close(fd);
		@@ -102,9 +68,7 @@ int ashmem_unpin_region(int fd __unused, size_t offset __unused, size_t len __un
		int ashmem_get_size_region(int fd)
		{
		struct stat buf;
		int result;

		result = fstat(fd, &buf);
		int result = fstat(fd, &buf);
		if (result == -1) {
		return -1;
		}
		@@ -116,5 +80,5 @@ int ashmem_get_size_region(int fd)
		return -1;
		}

		return (int)buf.st_size; // TODO: care about overflow (> 2GB file)?
		return buf.st_size;
		}