On Wed 21 Sep at 15:02:48 -0700 tpepper@xxxxxxxxx said:
>
> I wonder who would whinge on performance if the open/close simply
> happened everytime? Ie: remove initial state_fd=-2 and its associated
> special casing.
Something sort of like this for get_clock(), completely untested...
--
Tim Pepper <lnxninja@xxxxxxxxxxxxxxxxxx>
IBM Linux Technology Center
--- gen_uuid.c.orig 2011-09-16 14:14:58.902434595 -0700
+++ gen_uuid.c 2011-09-21 15:06:35.271419101 -0700
@@ -316,57 +316,48 @@ static int get_node_id(unsigned char *no
static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
uint16_t *ret_clock_seq, int *num)
{
- THREAD_LOCAL int adjustment = 0;
- THREAD_LOCAL struct timeval last = {0, 0};
- THREAD_LOCAL int state_fd = -2;
- THREAD_LOCAL FILE *state_f;
- THREAD_LOCAL uint16_t clock_seq;
+ int adjustment = 0;
+ struct timeval last = {0, 0};
+ int fd;
+ FILE *f;
+ uint16_t clock_seq;
struct timeval tv;
uint64_t clock_reg;
mode_t save_umask;
int len;
int ret = 0;
-
- if (state_fd == -2) {
- save_umask = umask(0);
- state_fd = open("/var/lib/libuuid/clock.txt",
- O_RDWR|O_CREAT, 0660);
- (void) umask(save_umask);
- if (state_fd != -1) {
- state_f = fdopen(state_fd, "r+");
- if (!state_f) {
- close(state_fd);
- state_fd = -1;
- ret = -1;
- }
+ unsigned int cl;
+ unsigned long tv1, tv2;
+ int a;
+
+ save_umask = umask(0);
+ fd = open("/var/lib/libuuid/clock.txt",
+ O_RDWR|O_CREAT, 0660);
+ (void) umask(save_umask);
+ if (fd != -1) {
+ f = fdopen(fd, "r+");
+ if (!f) {
+ close(fd);
+ return -1;
}
- else
- ret = -1;
}
- if (state_fd >= 0) {
- rewind(state_f);
- while (flock(state_fd, LOCK_EX) < 0) {
- if ((errno == EAGAIN) || (errno == EINTR))
- continue;
- fclose(state_f);
- close(state_fd);
- state_fd = -1;
- ret = -1;
- break;
- }
+ else
+ return -1;
+
+ while (flock(fd, LOCK_EX) < 0) {
+ if ((errno == EAGAIN) || (errno == EINTR))
+ continue;
+ fclose(f);
+ close(fd);
+ return -1;
}
- if (state_fd >= 0) {
- unsigned int cl;
- unsigned long tv1, tv2;
- int a;
-
- if (fscanf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
- &cl, &tv1, &tv2, &a) == 4) {
- clock_seq = cl & 0x3FFF;
- last.tv_sec = tv1;
- last.tv_usec = tv2;
- adjustment = a;
- }
+
+ if (fscanf(f, "clock: %04x tv: %lu %lu adj: %d\n",
+ &cl, &tv1, &tv2, &a) == 4) {
+ clock_seq = cl & 0x3FFF;
+ last.tv_sec = tv1;
+ last.tv_usec = tv2;
+ adjustment = a;
}
if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
@@ -406,19 +397,18 @@ try_again:
last.tv_usec = last.tv_usec % 1000000;
}
- if (state_fd >= 0) {
- rewind(state_f);
- len = fprintf(state_f,
- "clock: %04x tv: %016lu %08lu adj: %08d\n",
- clock_seq, last.tv_sec, last.tv_usec, adjustment);
- fflush(state_f);
- if (ftruncate(state_fd, len) < 0) {
- fprintf(state_f, " \n");
- fflush(state_f);
- }
- rewind(state_f);
- flock(state_fd, LOCK_UN);
- }
+ rewind(f);
+ len = fprintf(f,
+ "clock: %04x tv: %016lu %08lu adj: %08d\n",
+ clock_seq, last.tv_sec, last.tv_usec, adjustment);
+ fflush(f);
+ if (ftruncate(fd, len) < 0) {
+ fprintf(f, " \n");
+ fflush(f);
+ }
+ fclose(f);
+ flock(fd, LOCK_UN);
+ close(fd);
*clock_high = clock_reg >> 32;
*clock_low = clock_reg;
--
To unsubscribe from this list: send the line "unsubscribe util-linux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
