Found because 'stress-ng --fcntl 2 --verify' reports "ftruncate failed,
errno=21":
Testcase:
$ uname -r # also with 3.6.0-1 and 3.5.7-1
3.7.0-0.43.g779e46b5b3ee.x86_64
$ cat ftruncopen.c
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
int main()
{
const char name[] = "file.tmp";
unlink(name);
pid_t pid = fork();
if (pid == (pid_t)-1) {
perror("fork"); return 1;
}
int status = 1;
int fd = open(name, O_WRONLY|O_CREAT|O_TRUNC, 0600);
if (fd < 0) {
fprintf(stderr, "%d: ", (int)getpid()); perror("open");
}
else if (!pid && ftruncate(fd, 0) < 0) {
fprintf(stderr, "%d: ", (int)getpid()); perror("ftruncate");
}
else
status = 0;
printf("%d: exit(%d)\n", (int)getpid(), status);
if (!pid)
return status;
int status2 = 0;
wait(&status2);
return (status || status2);
}
$ gcc -o ftruncopen ftruncopen.c
$ while ./ftruncopen; do echo retry; done
11223: exit(0)
11222: exit(0)
retry
11225: exit(0)
11224: exit(0)
retry
11227: ftruncate: Is a directory
11226: exit(0)
11227: exit(1)
Problem did not occur if
- O_TRUNC is removed, or
- unlink() is removed and the file exists, or
- it is run with 'taskset 0x1'.
--
Regards,
Christian
--
Problem reports: https://cygwin.com/problems.html
FAQ: https://cygwin.com/faq/
Documentation: https://cygwin.com/docs.html
Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
