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Merge "Use mkstemp for host ashmem."

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Elliott Hughes 2015-02-09 21:53:12 +00:00 • committed by Gerrit Code Review
commit 3bc8ae63ce
1 changed files with 7 additions and 43 deletions
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50
libcutils/ashmem-host.c
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@ -22,7 +22,6 @@
#include <errno.h> #include <errno.h>
#include <fcntl.h> #include <fcntl.h>
#include <limits.h> #include <limits.h>
#include <pthread.h>
#include <stdbool.h> #include <stdbool.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
@ -33,51 +32,18 @@
#include <unistd.h> #include <unistd.h>
#include <cutils/ashmem.h> #include <cutils/ashmem.h>
#include <utils/Compat.h>
#ifndef __unused #ifndef __unused
#define __unused __attribute__((__unused__)) #define __unused __attribute__((__unused__))
#endif #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) int ashmem_create_region(const char *ignored __unused, size_t size)
{ {
static const char txt[] = "abcdefghijklmnopqrstuvwxyz" char template[PATH_MAX];
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"; snprintf(template, sizeof(template), "/tmp/android-ashmem-%d-XXXXXXXXX", getpid());
char name[64]; int fd = mkstemp(template);
unsigned int retries = 0; if (fd != -1 && TEMP_FAILURE_RETRY(ftruncate(fd, size)) != -1 && unlink(template) != -1) {
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; return fd;
} }
close(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) int ashmem_get_size_region(int fd)
{ {
struct stat buf; struct stat buf;
int result; int result = fstat(fd, &buf);
result = fstat(fd, &buf);
if (result == -1) { if (result == -1) {
return -1; return -1;
} }
@ -116,5 +80,5 @@ int ashmem_get_size_region(int fd)
return -1; return -1;
} }
return (int)buf.st_size; // TODO: care about overflow (> 2GB file)? return buf.st_size;
} }