I am trying to write a plugin in nginx, I should create a file in main process then child process will read this file. I have set the file 0766 in main process, but open and statvfs failed when I try to open the file in child process, the errno is 13 which means Permission denied.
Is there any special settings between parent and child processes? How can I solve it?
my code is like this:
// in nginx main process I create the file
u_char* shared_addr = NULL;
int map_my_file(const char* path)
{
extern int errno;
umask(0);
int fd = open(path, O_RDWR | O_CREAT | O_EXCL, 0766);
if (fd < 0)
{
ngx_log_stderr(0, "open file failed %s, %d", path, errno);
}
if (ftruncate(fd, 1024 *1024) < 0)
{
printf("ftruncate %d failed", fd);
}
shared_addr = (u_char*)mmap(NULL, 1024 * 1024, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
close(fd);
}
// in nginx child process, I try to open the file
int cfd = 0;
if ((cfd = open("./t.log", O_RDWR)) >= 0)
{
printf("child open success\n");
} else {
printf("failed %d\n", errno);
}
// I got `failed 13`, means `Permission denied`
If I take these create and open codes out separately and put them in a sample parent-child process case, it can works correctly. But it can not work in nginx, always told me 13.
