For a while now, the test cases that come with libapr1 have been
bombing with this message:
*** fatal error - NtCreateEvent(lock): 0xC0000035
I finally took some time to investigate and have extracted a STC
that demonstrates the problem.
It's been a decade since I did any C programming, so I'm not really
sure that the STC is valid. However, it does work on my Debian
box. (I know that doesn't really mean anything, but it's the best I
can do.)
I've tried this on my Win7-64 box running the 20110822 snapshot and
on a WinXP VM running 1.7.9. I get the same results in both places.
Regards,
David
--
David Rothenberger ---- daver...@acm.org
The First Rule of Program Optimization:
Don't do it.
The Second Rule of Program Optimization (for experts only!):
Don't do it yet.
-- Michael Jackson
/***********************************************************************
* This is a STC that causes the following error on my test machine:
* NtCreateEvent(lock): 0xC0000035
*
* It tries to use flock() for file locking. It creates a temporary
* file, the uses fork to spawn a number of children. Each child opens
* the file, then repeatedly uses flock to lock and unlock it.
*
* This test was extracted from the APR test suite.
*
* Compile: gcc -Wall -o stc-flock-fork stc-flock-fork.c
***********************************************************************/
#include <sys/types.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#define MAX_ITER 2000
#define CHILDREN 6
/* A temporary file used for flock. */
char tmpfilename[] = "/tmp/flocktstXXXXXX";
/* Fork and use flock to lock and unlock the file repeatedly in the child. */
void make_child(int trylock, pid_t *pid)
{
if ((*pid = fork()) < 0) {
perror("fork failed");
exit(1);
}
else if (*pid == 0) {
int fd2 = open(tmpfilename, O_RDONLY);
if (fd2 < 0) {
perror("child open");
exit(1);
}
int rc;
int i;
for (i=0; i<MAX_ITER; ++i) {
do {
rc = flock(fd2, LOCK_EX);
} while (rc < 0 && errno == EINTR);
if (rc < 0) {
perror("lock");
exit(1);
}
do {
rc = flock(fd2, LOCK_UN);
} while (rc < 0 && errno == EINTR);
if (rc < 0) {
perror("unlock");
exit(1);
}
}
exit(0);
}
}
/* Wait for the child to finish. */
void await_child(pid_t pid)
{
pid_t pstatus;
int exit_int;
do {
pstatus = waitpid(pid, &exit_int, WUNTRACED);
} while (pstatus < 0 && errno == EINTR);
}
int main(int argc, const char * const * argv, const char * const *env)
{
pid_t child[CHILDREN];
int n;
int fd;
/* Create the temporary file. */
fd = mkstemp(tmpfilename);
if (fd < 0) {
perror("open failed");
exit(1);
}
close(fd);
/* Create the children. */
for (n = 0; n < CHILDREN; n++)
make_child(0, &child[n]);
/* Wait for them to finish. */
for (n = 0; n < CHILDREN; n++)
await_child(child[n]);
/* Clean up. */
unlink(tmpfilename);
return 0;
}
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