diff options
Diffstat (limited to 'include/linux/poll.h')
-rw-r--r-- | include/linux/poll.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/include/linux/poll.h b/include/linux/poll.h index 2001fedfb..01c4d1519 100644 --- a/include/linux/poll.h +++ b/include/linux/poll.h @@ -1 +1,106 @@ +#ifndef _LINUX_POLL_H + #include <asm/poll.h> + +#ifdef __KERNEL__ + +#include <linux/wait.h> +#include <linux/string.h> +#include <asm/uaccess.h> + + +struct poll_table_entry { + struct wait_queue wait; + struct wait_queue ** wait_address; +}; + +typedef struct poll_table_struct { + unsigned int nr; + struct poll_table_entry * entry; +} poll_table; + +#define __MAX_POLL_TABLE_ENTRIES (PAGE_SIZE / sizeof (struct poll_table_entry)) + +extern inline void poll_wait(struct wait_queue ** wait_address, poll_table *p) +{ + struct poll_table_entry * entry; + + if (!p || !wait_address) + return; + if (p->nr >= __MAX_POLL_TABLE_ENTRIES) + return; + entry = p->entry + p->nr; + entry->wait_address = wait_address; + entry->wait.task = current; + entry->wait.next = NULL; + add_wait_queue(wait_address,&entry->wait); + p->nr++; +} + + +/* + * For the kernel fd_set we use a fixed set-size for allocation purposes. + * This set-size doesn't necessarily bear any relation to the size the user + * uses, but should preferably obviously be larger than any possible user + * size (NR_OPEN bits). + * + * We need 6 bitmaps (in/out/ex for both incoming and outgoing), and we + * allocate one page for all the bitmaps. Thus we have 8*PAGE_SIZE bits, + * to be divided by 6. And we'd better make sure we round to a full + * long-word (in fact, we'll round to 64 bytes). + */ + + +#define KFDS_64BLOCK ((PAGE_SIZE/(6*64))*64) +#define KFDS_NR (KFDS_64BLOCK*8 > NR_OPEN ? NR_OPEN : KFDS_64BLOCK*8) +typedef unsigned long kernel_fd_set[KFDS_NR/__NFDBITS]; + +typedef struct { + kernel_fd_set in, out, ex; + kernel_fd_set res_in, res_out, res_ex; +} fd_set_buffer; + + +/* + * We do a VERIFY_WRITE here even though we are only reading this time: + * we'll write to it eventually.. + * + * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned. + */ +static inline +int get_fd_set(unsigned long nr, void *ufdset, unsigned long *fdset) +{ + /* round up nr to nearest "unsigned long" */ + nr = (nr + 8*sizeof(long) - 1) / (8*sizeof(long)) * sizeof(long); + if (ufdset) { + int error; + error = verify_area(VERIFY_WRITE, ufdset, nr); + if (!error) + error = __copy_from_user(fdset, ufdset, nr); + return error; + } + memset(fdset, 0, nr); + return 0; +} + +static inline +void set_fd_set(unsigned long nr, void *ufdset, unsigned long *fdset) +{ + if (ufdset) { + nr = (nr + 8*sizeof(long) - 1) / (8*sizeof(long))*sizeof(long); + __copy_to_user(ufdset, fdset, nr); + } +} + +static inline +void zero_fd_set(unsigned long nr, unsigned long *fdset) +{ + nr = (nr + 8*sizeof(long) - 1) / (8*sizeof(long)) * sizeof(long); + memset(fdset, 0, nr); +} + +extern int do_select(int n, fd_set_buffer *fds, unsigned long timeout); + +#endif /* KERNEL */ + +#endif /* _LINUX_POLL_H */ |