minix/drivers/log/log.h
David van Moolenbroek c51cd5fe91 Server/driver protocols: no longer allow third-party copies.
Before safecopies, the IO_ENDPT and DL_ENDPT message fields were needed
to know which actual process to copy data from/to, as that process may
not always be the caller. Now that we have full safecopy support, these
fields have become useless for that purpose: the owner of the grant is
*always* the caller. Allowing the caller to supply another endpoint is
in fact dangerous, because the callee may then end up using a grant
from a third party. One could call this a variant of the confused
deputy problem.

From now on, safecopy calls should always use the caller's endpoint as
grant owner. This fully obsoletes the DL_ENDPT field in the
inet/ethernet protocol. IO_ENDPT has other uses besides identifying the
grant owner though. This patch renames IO_ENDPT to USER_ENDPT, not only
because that is a more fitting name (it should never be used for I/O
after all), but also in order to intentionally break any old system
source code outside the base system. If this patch breaks your code,
fixing it is fairly simple:

- DL_ENDPT should be replaced with m_source;
- IO_ENDPT should be replaced with m_source when used for safecopies;
- IO_ENDPT should be replaced with USER_ENDPT for any other use, e.g.
  when setting REP_ENDPT, matching requests in CANCEL calls, getting
  DEV_SELECT flags, and retrieving of the real user process's endpoint
  in DEV_OPEN.

The changes in this patch are binary backward compatible.
2011-04-11 17:35:05 +00:00

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C

/* Includes. */
#include <minix/drivers.h>
#include <minix/driver.h>
#include <minix/type.h>
#include <minix/const.h>
#include <minix/com.h>
#include <sys/types.h>
#include <minix/ipc.h>
/* Constants and types. */
#define LOG_SIZE (50*1024)
#define SUSPENDABLE 1
struct logdevice {
char log_buffer[LOG_SIZE];
int log_size, /* no. of bytes in log buffer */
log_read, /* read mark */
log_write; /* write mark */
#if SUSPENDABLE
endpoint_t log_proc_nr,
log_source;
int log_iosize,
log_revive_alerted,
log_status;
cp_grant_id_t log_user_grant;
vir_bytes log_user_offset;
#endif
int log_selected, log_select_proc,
log_select_alerted, log_select_ready_ops;
};
/* Function prototypes. */
_PROTOTYPE( void do_new_kmess, (void) );
_PROTOTYPE( void log_append, (char *buf, int len) );