On 2010-04-27, at 10:13, Aneesh Kumar K.V wrote:
> Changes from V5:
> a) added sys_name_to_handle_at syscall which takes AT_SYMLINK_NOFOLLOW flag
> instead of two syscalls sys_name_to_handle and sys_lname_to_handle.
>
> #define AT_FDCWD -100
> #define AT_SYMLINK_NOFOLLOW 0x100
>
> static int name_to_handle(const char *name, struct file_handle *fh)
> {
> return syscall(338, AT_FDCWD, name, fh, 0);
> }
>
> static int lname_to_handle(const char *name, struct file_handle *fh)
> {
> return syscall(338, AT_FDCWD, name, fh, AT_SYMLINK_NOFOLLOW);
> }
>
> static int open_by_handle(struct file_handle *fh, int flags)
> {
> return syscall(339, fh, flags);
> }
>
> static int freadlink(int fd, char *buf, size_t bufsiz)
> {
> return syscall(340, fd, buf, bufsiz);
> }
Your example, while #defining the AT_* stuff, did not actually change to use the _at() interface.
> #define BUFSZ 100
> int main(int argc, char *argv[])
> {
> int ret;
> int handle_sz;
> struct stat bufstat;
> int fd, dirfd;
> char buf[BUFSZ];
> struct file_handle *fh = NULL;;
> again:
> if (fh && fh->handle_size) {
> handle_sz = fh->handle_size;
> free(fh);
> fh = malloc(sizeof(struct file_handle) + handle_sz);
> fh->handle_size = handle_sz;
> } else {
> fh = malloc(sizeof(struct file_handle));
> fh->handle_size = 0;
> }
> errno = 0;
> ret = lname_to_handle(argv[1], fh);
> if (ret && errno == EOVERFLOW) {
> perror("Error:");
> printf("Found the handle size needed to be %d\n", fh->handle_size);
> printf("Trying again..\n");
> goto again;
> } else if (ret) {
> perror("Error:");
> exit(1);
> }
> fd = open_by_handle(fh, O_RDONLY);
> if (fd <= 0 ) {
> perror("Error:");
> exit(1);
> }
> fstat(fd, &bufstat);
> ret = S_ISLNK(bufstat.st_mode);
> if (ret) {
> memset(buf, 0 , BUFSZ);
> freadlink(fd, buf, BUFSZ);
> printf("%s is a symlink pointing to %s\n", argv[1], buf);
> }
> memset(buf, 0 , BUFSZ);
> while (1) {
> ret = read(fd, buf, BUFSZ -1);
> if (ret <= 0)
> break;
> buf[ret] = '\0';
> printf("%s", buf);
> memset(buf, 0 , BUFSZ);
> }
> return 0;
> }
Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
