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Commit b5ad0f12 authored by Adam Wujek's avatar Adam Wujek 💬
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userspace/libwr: in shmem, use pointers to structs intead of void pointers 

In shared memory functions take as parameters pinters to structures instead
of void pointers. By this compiler will warn when wrong type of pointer is
passed. For example when pointer to the data in shmem is passed instead of
pointer to the header.
Signed-off-by: Adam Wujek's avatarAdam Wujek <adam.wujek@cern.ch>
parent 8746815f
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Showing with 29 additions and 35 deletions
userspace/libwr/include/libwr/shmem.h
View file @ b5ad0f12
......@@ -61,19 +61,21 @@ void wrs_shm_set_path(char *new_path);
void wrs_shm_ignore_flag_locked(int ignore_flag);
/* get vs. put, like in the kernel. Errors are in errno (see source) */
void *wrs_shm_get(enum wrs_shm_name name_id, char *name, unsigned long flags);
int wrs_shm_put(void *headptr);
struct wrs_shm_head *wrs_shm_get(enum wrs_shm_name name_id, char *name,
unsigned long flags);
int wrs_shm_put(struct wrs_shm_head *head);
/* A reader may wait for the writer (polling on version field) */
void wrs_shm_wait(void *headptr, int msec_step, int retries, FILE *msg);
void wrs_shm_wait(struct wrs_shm_head *head, int msec_step, int retries,
FILE *msg);
int wrs_shm_get_and_check(enum wrs_shm_name shm_name,
struct wrs_shm_head **head);
/* The writer can allocate structures that live in the area itself */
void *wrs_shm_alloc(void *headptr, size_t size);
void *wrs_shm_alloc(struct wrs_shm_head *head, size_t size);
/* The reader can track writer's pointers, if they are in the area */
void *wrs_shm_follow(void *headptr, void *ptr);
void *wrs_shm_follow(struct wrs_shm_head *head, void *ptr);
/* Before and after writing a chunk of data, act on sequence and stamp */
#define WRS_SHM_WRITE_BEGIN 1
......@@ -82,16 +84,17 @@ void *wrs_shm_follow(void *headptr, void *ptr);
/* A helper to pass the name of caller function */
#define wrs_shm_write(headptr, flags) wrs_shm_write_caller(headptr, flags, \
__func__)
extern void wrs_shm_write_caller(void *headptr, int flags, const char *caller);
extern void wrs_shm_write_caller(struct wrs_shm_head *head, int flags,
const char *caller);
/* A reader can rely on the sequence number (in the <linux/seqlock.h> way) */
extern unsigned wrs_shm_seqbegin(void *headptr);
extern int wrs_shm_seqretry(void *headptr, unsigned start);
extern unsigned wrs_shm_seqbegin(struct wrs_shm_head *head);
extern int wrs_shm_seqretry(struct wrs_shm_head *head, unsigned start);
/* A reader can check wether information is current enough */
extern int wrs_shm_age(void *headptr);
extern int wrs_shm_age(struct wrs_shm_head *head);
/* A reader can get the information pointer, for a specific version, or NULL */
extern void *wrs_shm_data(void *headptr, unsigned version);
extern void *wrs_shm_data(struct wrs_shm_head *head, unsigned version);
#endif /* __WRS_SHM_H__ */
userspace/libwr/shmem.c
View file @ b5ad0f12
......@@ -39,7 +39,8 @@ void wrs_shm_ignore_flag_locked(int ignore_flag)
/* Get wrs shared memory */
/* return NULL and set errno on error */
void *wrs_shm_get(enum wrs_shm_name name_id, char *name, unsigned long flags)
struct wrs_shm_head *wrs_shm_get(enum wrs_shm_name name_id, char *name,
unsigned long flags)
{
struct wrs_shm_head *head;
struct stat stbuf;
......@@ -120,20 +121,19 @@ void *wrs_shm_get(enum wrs_shm_name name_id, char *name, unsigned long flags)
head->pidsequence++;
/* version and size are up to the user (or to allocation) */
return map;
return (struct wrs_shm_head *) map;
}
/* Put wrs shared memory */
/* return 0 on success, !0 on error */
int wrs_shm_put(void *headptr)
int wrs_shm_put(struct wrs_shm_head *head)
{
struct wrs_shm_head *head = headptr;
int err;
if (head->pid == getpid()) {
head->pid = 0; /* mark that we are not writers any more */
close(head->fd);
}
if ((err = munmap(headptr, WRS_SHM_MAX_SIZE)) < 0)
if ((err = munmap(head, WRS_SHM_MAX_SIZE)) < 0)
return err;
return 0;
}
......@@ -175,9 +175,9 @@ int wrs_shm_get_and_check(enum wrs_shm_name shm_name,
}
/* The writer can allocate structures that live in the area itself */
void *wrs_shm_alloc(void *headptr, size_t size)
void *wrs_shm_alloc(struct wrs_shm_head *head, size_t size)
{
struct wrs_shm_head *head = headptr;
void *headptr = (void *) head;
void *nextptr;
if (head->pid != getpid())
......@@ -196,20 +196,18 @@ void *wrs_shm_alloc(void *headptr, size_t size)
}
/* The reader can track writer's pointers, if they are in the area */
void *wrs_shm_follow(void *headptr, void *ptr)
void *wrs_shm_follow(struct wrs_shm_head *head, void *ptr)
{
struct wrs_shm_head *head = headptr;
void *headptr = (void *) head;
if (ptr < head->mapbase || ptr > head->mapbase + WRS_SHM_MAX_SIZE)
return NULL; /* not in the area */
return headptr + (ptr - head->mapbase);
}
/* Before and after writing a chunk of data, act on sequence and stamp */
void wrs_shm_write_caller(void *headptr, int flags, const char *caller)
void wrs_shm_write_caller(struct wrs_shm_head *head, int flags,
const char *caller)
{
struct wrs_shm_head *head = headptr;
head->sequence += 2;
pr_debug("caller of a function %s is %s\n", __func__, caller);
......@@ -237,17 +235,13 @@ void wrs_shm_write_caller(void *headptr, int flags, const char *caller)
}
/* A reader can rely on the sequence number (in the <linux/seqlock.h> way) */
unsigned wrs_shm_seqbegin(void *headptr)
unsigned wrs_shm_seqbegin(struct wrs_shm_head *head)
{
struct wrs_shm_head *head = headptr;
return head->sequence;
}
int wrs_shm_seqretry(void *headptr, unsigned start)
int wrs_shm_seqretry(struct wrs_shm_head *head, unsigned start)
{
struct wrs_shm_head *head = headptr;
if (start & WRS_SHM_LOCK_MASK)
return 1; /* it was odd: retry */
......@@ -255,18 +249,15 @@ int wrs_shm_seqretry(void *headptr, unsigned start)
}
/* A reader can check wether information is current enough */
int wrs_shm_age(void *headptr)
int wrs_shm_age(struct wrs_shm_head *head)
{
struct wrs_shm_head *head = headptr;
return get_monotonic_sec() - head->stamp;
}
/* A reader can get the information pointer, for a specific version, or NULL */
void *wrs_shm_data(void *headptr, unsigned version)
void *wrs_shm_data(struct wrs_shm_head *head, unsigned version)
{
struct wrs_shm_head *head = headptr;
void *headptr = (void *) head;
if (head->version != version)
return NULL;
......
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