lib: Refactor shm_rdrbuff and shm_rbuff

This refactors the creation of shm_rdrbuff and shm_rbuff elements. All
cleanup is now handled and the common code between the _open() and
_create() calls is moved to a static function. Common code between the
pthread and lockless rbuff implementations was moved to shm_rbuff.c

Signed-off-by: Dimitri Staessens <dimitri.staessens@ugent.be>
Signed-off-by: Sander Vrijders <sander.vrijders@ugent.be>

4 files changed, 286 insertions, 497 deletions

diff --git a/src/lib/shm_rbuff.c b/src/lib/shm_rbuff.c
index 93108332..00f0b92b 100644
--- a/src/lib/shm_rbuff.c
+++ b/src/lib/shm_rbuff.c
@@ -24,6 +24,181 @@
 
 #include "config.h"
 
+#include <ouroboros/shm_rbuff.h>
+#include <ouroboros/lockfile.h>
+#include <ouroboros/time_utils.h>
+#include <ouroboros/errno.h>
+#include <ouroboros/fccntl.h>
+
+#include <pthread.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#define FN_MAX_CHARS 255
+
+#define SHM_RB_FILE_SIZE ((SHM_BUFFER_SIZE) * sizeof(ssize_t)          \
+                          + 3 * sizeof(size_t)                          \
+                          + sizeof(pthread_mutex_t)                     \
+                          + 2 * sizeof (pthread_cond_t))
+
+#define shm_rbuff_used(rb) ((*rb->head + (SHM_BUFFER_SIZE) - *rb->tail)   \
+                            & ((SHM_BUFFER_SIZE) - 1))
+#define shm_rbuff_free(rb) (shm_rbuff_used(rb) + 1 < (SHM_BUFFER_SIZE))
+#define shm_rbuff_empty(rb) (*rb->head == *rb->tail)
+#define head_el_ptr(rb) (rb->shm_base + *rb->head)
+#define tail_el_ptr(rb) (rb->shm_base + *rb->tail)
+
+struct shm_rbuff {
+        ssize_t *         shm_base; /* start of entry                */
+        size_t *          head;     /* start of ringbuffer head      */
+        size_t *          tail;     /* start of ringbuffer tail      */
+        size_t *          acl;      /* access control                */
+        pthread_mutex_t * lock;     /* lock all free space in shm    */
+        pthread_cond_t *  add;      /* SDU arrived                   */
+        pthread_cond_t *  del;      /* SDU removed                   */
+        pid_t             api;      /* api of the owner              */
+        int               port_id;  /* port_id of the flow           */
+};
+
+void shm_rbuff_close(struct shm_rbuff * rb)
+{
+        assert(rb);
+
+        munmap(rb->shm_base, SHM_RB_FILE_SIZE);
+
+        free(rb);
+}
+
+#define MM_FLAGS (PROT_READ | PROT_WRITE)
+
+struct shm_rbuff * rbuff_create(pid_t api, int port_id, int flags)
+{
+        struct shm_rbuff * rb;
+        int                fd;
+        ssize_t *          shm_base;
+        char               fn[FN_MAX_CHARS];
+
+        sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
+
+        rb = malloc(sizeof(*rb));
+        if (rb == NULL)
+                goto fail_malloc;
+
+        fd = shm_open(fn, flags, 0666);
+        if (fd == -1)
+                goto fail_open;
+
+        if ((flags & O_CREAT) && ftruncate(fd, SHM_RB_FILE_SIZE - 1) < 0)
+                goto fail_truncate;
+
+        shm_base = mmap(NULL, SHM_RB_FILE_SIZE, MM_FLAGS, MAP_SHARED, fd, 0);
+        if (shm_base == MAP_FAILED)
+                goto fail_truncate;
+
+        close(fd);
+
+        rb->shm_base = shm_base;
+        rb->head     = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
+        rb->tail     = rb->head + 1;
+        rb->acl      = rb->tail + 1;
+        rb->lock     = (pthread_mutex_t *) (rb->acl + 1);
+        rb->add      = (pthread_cond_t *) (rb->lock + 1);
+        rb->del      = rb->add + 1;
+
+        rb->api = api;
+        rb->port_id = port_id;
+
+        return rb;
+
+ fail_truncate:
+        close(fd);
+        if (flags & O_CREAT)
+                shm_unlink(fn);
+ fail_open:
+        free(rb);
+ fail_malloc:
+        return NULL;
+}
+
+struct shm_rbuff * shm_rbuff_create(pid_t api, int port_id)
+{
+        struct shm_rbuff *  rb;
+        pthread_mutexattr_t mattr;
+        pthread_condattr_t  cattr;
+        mode_t              mask;
+
+        mask = umask(0);
+
+        rb = rbuff_create(api, port_id, O_CREAT | O_EXCL | O_RDWR);
+
+        umask(mask);
+
+        if (rb == NULL)
+                goto fail_rb;
+
+        if (pthread_mutexattr_init(&mattr))
+                goto fail_mattr;
+
+        pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
+#ifdef HAVE_ROBUST_MUTEX
+        pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
+#endif
+        if (pthread_mutex_init(rb->lock, &mattr))
+                goto fail_mutex;
+
+        if (pthread_condattr_init(&cattr))
+                goto fail_cattr;
+
+        pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
+#ifndef __APPLE__
+        pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
+#endif
+        if (pthread_cond_init(rb->add, &cattr))
+                goto fail_add;
+
+        if (pthread_cond_init(rb->del, &cattr))
+                goto fail_del;
+
+        *rb->acl  = ACL_RDWR;
+        *rb->head = 0;
+        *rb->tail = 0;
+
+        rb->api = api;
+        rb->port_id = port_id;
+
+        pthread_mutexattr_destroy(&mattr);
+        pthread_condattr_destroy(&cattr);
+
+        return rb;
+
+ fail_del:
+        pthread_cond_destroy(rb->add);
+ fail_add:
+        pthread_condattr_destroy(&cattr);
+ fail_cattr:
+        pthread_mutex_destroy(rb->lock);
+ fail_mutex:
+        pthread_mutexattr_destroy(&mattr);
+ fail_mattr:
+        shm_rbuff_destroy(rb);
+ fail_rb:
+        return NULL;
+}
+
+struct shm_rbuff * shm_rbuff_open(pid_t api, int port_id)
+{
+        return rbuff_create(api, port_id, O_RDWR);
+}
+
 #if (defined(SHM_RBUFF_LOCKLESS) &&                            \
      (defined(__GNUC__) || defined (__clang__)))
 #include "shm_rbuff_ll.c"
diff --git a/src/lib/shm_rbuff_ll.c b/src/lib/shm_rbuff_ll.c
index b77c4374..6ac9af47 100644
--- a/src/lib/shm_rbuff_ll.c
+++ b/src/lib/shm_rbuff_ll.c
@@ -20,193 +20,9 @@
  * Foundation, Inc., http://www.fsf.org/about/contact/.
  */
 
-#include "config.h"
-
-#include <ouroboros/shm_rbuff.h>
-#include <ouroboros/lockfile.h>
-#include <ouroboros/time_utils.h>
-#include <ouroboros/errno.h>
-#include <ouroboros/fccntl.h>
-
-#include <pthread.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <signal.h>
-#include <sys/stat.h>
-#include <assert.h>
-#include <stdbool.h>
-
-#define FN_MAX_CHARS 255
-
-#define SHM_RBUFF_FILE_SIZE ((SHM_BUFFER_SIZE) * sizeof(ssize_t)        \
-                             + 3 * sizeof(size_t)                       \
-                             + sizeof(pthread_mutex_t)                  \
-                             + 2 * sizeof (pthread_cond_t))
-
 #define RB_HEAD __sync_fetch_and_add(rb->head, 0)
 #define RB_TAIL __sync_fetch_and_add(rb->tail, 0)
 
-#define shm_rbuff_used(rb) ((RB_HEAD + (SHM_BUFFER_SIZE) - RB_TAIL)     \
-                            & ((SHM_BUFFER_SIZE) - 1))
-#define shm_rbuff_free(rb) (shm_rbuff_used(rb) + 1 < (SHM_BUFFER_SIZE))
-#define shm_rbuff_empty(rb) (RB_HEAD == RB_TAIL)
-#define head_el_ptr(rb) (rb->shm_base + RB_HEAD)
-#define tail_el_ptr(rb) (rb->shm_base + RB_TAIL)
-
-struct shm_rbuff {
-        ssize_t *         shm_base; /* start of entry                */
-        size_t *          head;     /* start of ringbuffer head      */
-        size_t *          tail;     /* start of ringbuffer tail      */
-        size_t *          acl;      /* access control                */
-        pthread_mutex_t * lock;     /* lock all free space in shm    */
-        pthread_cond_t *  add;      /* SDU arrived                   */
-        pthread_cond_t *  del;      /* SDU removed                   */
-        pid_t             api;      /* api of the owner              */
-        int               port_id;  /* port_id of the flow           */
-};
-
-struct shm_rbuff * shm_rbuff_create(pid_t api, int port_id)
-{
-        struct shm_rbuff *  rb;
-        int                 shm_fd;
-        ssize_t *           shm_base;
-        pthread_mutexattr_t mattr;
-        pthread_condattr_t  cattr;
-        char                fn[FN_MAX_CHARS];
-        mode_t              mask;
-
-        sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
-
-        rb = malloc(sizeof(*rb));
-        if (rb == NULL)
-                return NULL;
-
-        mask = umask(0);
-
-        shm_fd = shm_open(fn, O_CREAT | O_EXCL | O_RDWR, 0666);
-        if (shm_fd == -1) {
-                free(rb);
-                return NULL;
-        }
-
-        umask(mask);
-
-        if (ftruncate(shm_fd, SHM_RBUFF_FILE_SIZE - 1) < 0) {
-                free(rb);
-                close(shm_fd);
-                return NULL;
-        }
-
-        shm_base = mmap(NULL,
-                        SHM_RBUFF_FILE_SIZE,
-                        PROT_READ | PROT_WRITE,
-                        MAP_SHARED,
-                        shm_fd,
-                        0);
-
-        close(shm_fd);
-
-        if (shm_base == MAP_FAILED) {
-                shm_unlink(fn);
-                free(rb);
-                return NULL;
-        }
-
-        rb->shm_base = shm_base;
-        rb->head     = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
-        rb->tail     = rb->head + 1;
-        rb->acl      = rb->tail + 1;
-        rb->lock     = (pthread_mutex_t *) (rb->acl + 1);
-        rb->add      = (pthread_cond_t *) (rb->lock + 1);
-        rb->del      = rb->add + 1;
-
-        pthread_mutexattr_init(&mattr);
-#ifdef HAVE_ROBUST_MUTEX
-        pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
-#endif
-        pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
-        pthread_mutex_init(rb->lock, &mattr);
-
-        pthread_condattr_init(&cattr);
-        pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
-#ifndef __APPLE__
-        pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
-#endif
-        pthread_cond_init(rb->add, &cattr);
-        pthread_cond_init(rb->del, &cattr);
-
-        *rb->acl = ACL_RDWR;
-        *rb->head = 0;
-        *rb->tail = 0;
-
-        rb->api = api;
-        rb->port_id = port_id;
-
-        return rb;
-}
-
-struct shm_rbuff * shm_rbuff_open(pid_t api, int port_id)
-{
-        struct shm_rbuff * rb;
-        int                shm_fd;
-        ssize_t *          shm_base;
-        char               fn[FN_MAX_CHARS];
-
-        sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
-
-        rb = malloc(sizeof(*rb));
-        if (rb == NULL)
-                return NULL;
-
-        shm_fd = shm_open(fn, O_RDWR, 0666);
-        if (shm_fd == -1) {
-                free(rb);
-                return NULL;
-        }
-
-        shm_base = mmap(NULL,
-                        SHM_RBUFF_FILE_SIZE,
-                        PROT_READ | PROT_WRITE,
-                        MAP_SHARED,
-                        shm_fd,
-                        0);
-
-        close(shm_fd);
-
-        if (shm_base == MAP_FAILED) {
-                shm_unlink(fn);
-                free(rb);
-                return NULL;
-        }
-
-        rb->shm_base = shm_base;
-        rb->head     = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
-        rb->tail     = rb->head + 1;
-        rb->acl      = rb->tail + 1;
-        rb->lock     = (pthread_mutex_t *) (rb->acl + 1);
-        rb->add      = (pthread_cond_t *) (rb->lock + 1);
-        rb->del      = rb->add + 1;
-
-        rb->api = api;
-        rb->port_id = port_id;
-
-        return rb;
-}
-
-void shm_rbuff_close(struct shm_rbuff * rb)
-{
-        assert(rb);
-
-        munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE);
-
-        free(rb);
-}
-
 void shm_rbuff_destroy(struct shm_rbuff * rb)
 {
         char fn[FN_MAX_CHARS];
@@ -215,10 +31,9 @@ void shm_rbuff_destroy(struct shm_rbuff * rb)
 
         sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", rb->api, rb->port_id);
 
-        munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE);
-        shm_unlink(fn);
+        shm_rbuff_close(rb);
 
-        free(rb);
+        shm_unlink(fn);
 }
 
 int shm_rbuff_write(struct shm_rbuff * rb,
diff --git a/src/lib/shm_rbuff_pthr.c b/src/lib/shm_rbuff_pthr.c
index fb183d8f..565bb1fa 100644
--- a/src/lib/shm_rbuff_pthr.c
+++ b/src/lib/shm_rbuff_pthr.c
@@ -20,190 +20,6 @@
  * Foundation, Inc., http://www.fsf.org/about/contact/.
  */
 
-#define _POSIX_C_SOURCE 200809L
-
-#include <ouroboros/shm_rbuff.h>
-#include <ouroboros/lockfile.h>
-#include <ouroboros/time_utils.h>
-#include <ouroboros/errno.h>
-#include <ouroboros/fccntl.h>
-
-#include <pthread.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <signal.h>
-#include <sys/stat.h>
-#include <assert.h>
-#include <stdbool.h>
-
-#define FN_MAX_CHARS 255
-
-#define SHM_RBUFF_FILE_SIZE ((SHM_BUFFER_SIZE) * sizeof(ssize_t)          \
-                             + 3 * sizeof(size_t)                         \
-                             + sizeof(pthread_mutex_t)                    \
-                             + 2 * sizeof (pthread_cond_t))
-
-#define shm_rbuff_used(rb) ((*rb->head + (SHM_BUFFER_SIZE) - *rb->tail)   \
-                            & ((SHM_BUFFER_SIZE) - 1))
-#define shm_rbuff_free(rb) (shm_rbuff_used(rb) + 1 < (SHM_BUFFER_SIZE))
-#define shm_rbuff_empty(rb) (*rb->head == *rb->tail)
-#define head_el_ptr(rb) (rb->shm_base + *rb->head)
-#define tail_el_ptr(rb) (rb->shm_base + *rb->tail)
-
-struct shm_rbuff {
-        ssize_t *         shm_base; /* start of entry                */
-        size_t *          head;     /* start of ringbuffer head      */
-        size_t *          tail;     /* start of ringbuffer tail      */
-        size_t *          acl;      /* access control                */
-        pthread_mutex_t * lock;     /* lock all free space in shm    */
-        pthread_cond_t *  add;      /* SDU arrived                   */
-        pthread_cond_t *  del;      /* SDU removed                   */
-        pid_t             api;      /* api of the owner              */
-        int               port_id;  /* port_id of the flow           */
-};
-
-struct shm_rbuff * shm_rbuff_create(pid_t api, int port_id)
-{
-        struct shm_rbuff *  rb;
-        int                 shm_fd;
-        ssize_t *           shm_base;
-        pthread_mutexattr_t mattr;
-        pthread_condattr_t  cattr;
-        char                fn[FN_MAX_CHARS];
-        mode_t              mask;
-
-        sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
-
-        rb = malloc(sizeof(*rb));
-        if (rb == NULL)
-                return NULL;
-
-        mask = umask(0);
-
-        shm_fd = shm_open(fn, O_CREAT | O_EXCL | O_RDWR, 0666);
-        if (shm_fd == -1) {
-                free(rb);
-                return NULL;
-        }
-
-        umask(mask);
-
-        if (ftruncate(shm_fd, SHM_RBUFF_FILE_SIZE - 1) < 0) {
-                free(rb);
-                close(shm_fd);
-                return NULL;
-        }
-
-        shm_base = mmap(NULL,
-                        SHM_RBUFF_FILE_SIZE,
-                        PROT_READ | PROT_WRITE,
-                        MAP_SHARED,
-                        shm_fd,
-                        0);
-
-        close(shm_fd);
-
-        if (shm_base == MAP_FAILED) {
-                shm_unlink(fn);
-                free(rb);
-                return NULL;
-        }
-
-        rb->shm_base = shm_base;
-        rb->head     = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
-        rb->tail     = rb->head + 1;
-        rb->acl      = rb->tail + 1;
-        rb->lock     = (pthread_mutex_t *) (rb->acl + 1);
-        rb->add      = (pthread_cond_t *) (rb->lock + 1);
-        rb->del      = rb->add + 1;
-
-        pthread_mutexattr_init(&mattr);
-#ifdef HAVE_ROBUST_MUTEX
-        pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
-#endif
-        pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
-        pthread_mutex_init(rb->lock, &mattr);
-
-        pthread_condattr_init(&cattr);
-        pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
-#ifndef __APPLE__
-        pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
-#endif
-        pthread_cond_init(rb->add, &cattr);
-        pthread_cond_init(rb->del, &cattr);
-
-        *rb->acl  = ACL_RDWR;
-        *rb->head = 0;
-        *rb->tail = 0;
-
-        rb->api = api;
-        rb->port_id = port_id;
-
-        return rb;
-}
-
-struct shm_rbuff * shm_rbuff_open(pid_t api, int port_id)
-{
-        struct shm_rbuff * rb;
-        int                shm_fd;
-        ssize_t *          shm_base;
-        char               fn[FN_MAX_CHARS];
-
-        sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
-
-        rb = malloc(sizeof(*rb));
-        if (rb == NULL)
-                return NULL;
-
-        shm_fd = shm_open(fn, O_RDWR, 0666);
-        if (shm_fd == -1) {
-                free(rb);
-                return NULL;
-        }
-
-        shm_base = mmap(NULL,
-                        SHM_RBUFF_FILE_SIZE,
-                        PROT_READ | PROT_WRITE,
-                        MAP_SHARED,
-                        shm_fd,
-                        0);
-
-        close(shm_fd);
-
-        if (shm_base == MAP_FAILED) {
-                shm_unlink(fn);
-                free(rb);
-                return NULL;
-        }
-
-        rb->shm_base = shm_base;
-        rb->head     = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
-        rb->tail     = rb->head + 1;
-        rb->acl      = rb->tail + 1;
-        rb->lock     = (pthread_mutex_t *) (rb->acl + 1);
-        rb->add      = (pthread_cond_t *) (rb->lock + 1);
-        rb->del      = rb->add + 1;
-
-        rb->api = api;
-        rb->port_id = port_id;
-
-        return rb;
-}
-
-void shm_rbuff_close(struct shm_rbuff * rb)
-{
-        assert(rb);
-
-        munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE);
-
-        free(rb);
-}
-
 void shm_rbuff_destroy(struct shm_rbuff * rb)
 {
         char fn[FN_MAX_CHARS];
@@ -219,10 +35,9 @@ void shm_rbuff_destroy(struct shm_rbuff * rb)
 #endif
         sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", rb->api, rb->port_id);
 
-        munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE);
-        shm_unlink(fn);
+        shm_rbuff_close(rb);
 
-        free(rb);
+        shm_unlink(fn);
 }
 
 int shm_rbuff_write(struct shm_rbuff * rb,
diff --git a/src/lib/shm_rdrbuff.c b/src/lib/shm_rdrbuff.c
index 2853d5bb..4c00c74d 100644
--- a/src/lib/shm_rdrbuff.c
+++ b/src/lib/shm_rdrbuff.c
@@ -134,57 +134,62 @@ static char * rdrb_filename(void)
         return str;
 }
 
-struct shm_rdrbuff * shm_rdrbuff_create()
+void shm_rdrbuff_close(struct shm_rdrbuff * rdrb)
 {
-        struct shm_rdrbuff * rdrb;
-        mode_t               mask;
-        int                  shm_fd;
-        uint8_t *            shm_base;
-        pthread_mutexattr_t  mattr;
-        pthread_condattr_t   cattr;
-        char *               shm_rdrb_fn = rdrb_filename();
+        assert(rdrb);
+
+        munmap(rdrb->shm_base, SHM_FILE_SIZE);
+        free(rdrb);
+}
+
+void shm_rdrbuff_destroy(struct shm_rdrbuff * rdrb)
+{
+        char * shm_rdrb_fn;
+
+        assert(rdrb);
+
+        if (getpid() != *rdrb->api && kill(*rdrb->api, 0) == 0)
+                return;
+
+        shm_rdrbuff_close(rdrb);
+
+        shm_rdrb_fn = rdrb_filename();
         if (shm_rdrb_fn == NULL)
-                return NULL;
+                return;
 
-        rdrb = malloc(sizeof *rdrb);
-        if (rdrb == NULL) {
-                free(shm_rdrb_fn);
-                return NULL;
-        }
+        shm_unlink(shm_rdrb_fn);
+        free(shm_rdrb_fn);
+}
 
-        mask = umask(0);
+#define MM_FLAGS (PROT_READ | PROT_WRITE)
 
-        shm_fd = shm_open(shm_rdrb_fn, O_CREAT | O_EXCL | O_RDWR, 0666);
-        if (shm_fd == -1) {
-                free(shm_rdrb_fn);
-                free(rdrb);
-                return NULL;
-        }
+static struct shm_rdrbuff * rdrb_create(int flags)
+{
+        struct shm_rdrbuff * rdrb;
+        int                  fd;
+        uint8_t *            shm_base;
+        char *               shm_rdrb_fn;
 
-        umask(mask);
+        shm_rdrb_fn = rdrb_filename();
+        if (shm_rdrb_fn == NULL)
+                goto fail_fn;
 
-        if (ftruncate(shm_fd, SHM_FILE_SIZE - 1) < 0) {
-                free(shm_rdrb_fn);
-                close(shm_fd);
-                free(rdrb);
-                return NULL;
-        }
+        rdrb = malloc(sizeof *rdrb);
+        if (rdrb == NULL)
+                goto fail_rdrb;
 
-        shm_base = mmap(NULL,
-                        SHM_FILE_SIZE,
-                        PROT_READ | PROT_WRITE,
-                        MAP_SHARED,
-                        shm_fd,
-                        0);
+        fd = shm_open(shm_rdrb_fn, flags, 0666);
+        if (fd == -1)
+                goto fail_open;
 
-        close(shm_fd);
+        if ((flags & O_CREAT) && ftruncate(fd, SHM_FILE_SIZE - 1) < 0)
+                goto fail_truncate;
 
-        if (shm_base == MAP_FAILED) {
-                shm_unlink(shm_rdrb_fn);
-                free(shm_rdrb_fn);
-                free(rdrb);
-                return NULL;
-        }
+        shm_base = mmap(NULL, SHM_FILE_SIZE, MM_FLAGS, MAP_SHARED, fd, 0);
+        if (shm_base == MAP_FAILED)
+                goto fail_truncate;
+
+        close(fd);
 
         rdrb->shm_base = shm_base;
         rdrb->head = (size_t *) ((uint8_t *) rdrb->shm_base + SHM_BLOCKS_SIZE);
@@ -194,80 +199,88 @@ struct shm_rdrbuff * shm_rdrbuff_create()
         rdrb->healthy = rdrb->full + 1;
         rdrb->api = (pid_t *) (rdrb->healthy + 1);
 
-        pthread_mutexattr_init(&mattr);
+        free(shm_rdrb_fn);
+
+        return rdrb;
+
+ fail_truncate:
+        close(fd);
+        if (flags & O_CREAT)
+                shm_unlink(shm_rdrb_fn);
+ fail_open:
+        free(rdrb);
+ fail_rdrb:
+        free(shm_rdrb_fn);
+ fail_fn:
+        return NULL;
+}
+
+struct shm_rdrbuff * shm_rdrbuff_create()
+{
+        struct shm_rdrbuff * rdrb;
+        mode_t               mask;
+        pthread_mutexattr_t  mattr;
+        pthread_condattr_t   cattr;
+
+        mask = umask(0);
+
+        rdrb = rdrb_create(O_CREAT | O_EXCL | O_RDWR);
+
+        umask(mask);
+
+        if (rdrb == NULL)
+                goto fail_rdrb;
+
+        if (pthread_mutexattr_init(&mattr))
+                goto fail_mattr;
+
         pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
 #ifdef HAVE_ROBUST_MUTEX
         pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
 #endif
-        pthread_mutex_init(rdrb->lock, &mattr);
+        if (pthread_mutex_init(rdrb->lock, &mattr))
+                goto fail_mutex;
+
+        if (pthread_condattr_init(&cattr))
+                goto fail_cattr;
 
-        pthread_condattr_init(&cattr);
         pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
 #ifndef __APPLE__
         pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
 #endif
-        pthread_cond_init(rdrb->full, &cattr);
-        pthread_cond_init(rdrb->healthy, &cattr);
+        if (pthread_cond_init(rdrb->full, &cattr))
+                goto fail_full;
+
+        if (pthread_cond_init(rdrb->healthy, &cattr))
+                goto fail_healthy;
 
         *rdrb->head = 0;
         *rdrb->tail = 0;
 
         *rdrb->api = getpid();
 
-        free(shm_rdrb_fn);
+        pthread_mutexattr_destroy(&mattr);
+        pthread_condattr_destroy(&cattr);
 
         return rdrb;
+
+ fail_healthy:
+        pthread_cond_destroy(rdrb->full);
+ fail_full:
+        pthread_condattr_destroy(&cattr);
+ fail_cattr:
+        pthread_mutex_destroy(rdrb->lock);
+ fail_mutex:
+        pthread_mutexattr_destroy(&mattr);
+ fail_mattr:
+        shm_rdrbuff_destroy(rdrb);
+ fail_rdrb:
+         return NULL;
 }
 
 struct shm_rdrbuff * shm_rdrbuff_open()
 {
-        struct shm_rdrbuff * rdrb;
-        int                  shm_fd;
-        uint8_t *            shm_base;
-        char *               shm_rdrb_fn = rdrb_filename();
-        if (shm_rdrb_fn == NULL)
-                return NULL;
-
-        rdrb = malloc(sizeof *rdrb);
-        if (rdrb == NULL) {
-                free(shm_rdrb_fn);
-                return NULL;
-        }
-
-        shm_fd = shm_open(shm_rdrb_fn, O_RDWR, 0666);
-        if (shm_fd < 0) {
-                free(shm_rdrb_fn);
-                free(rdrb);
-                return NULL;
-        }
-
-        shm_base = mmap(NULL,
-                        SHM_FILE_SIZE,
-                        PROT_READ | PROT_WRITE,
-                        MAP_SHARED,
-                        shm_fd,
-                        0);
-
-        close(shm_fd);
-
-        if (shm_base == MAP_FAILED) {
-                shm_unlink(shm_rdrb_fn);
-                free(shm_rdrb_fn);
-                free(rdrb);
-                return NULL;
-        }
-
-        rdrb->shm_base = shm_base;
-        rdrb->head = (size_t *) ((uint8_t *) rdrb->shm_base + SHM_BLOCKS_SIZE);
-        rdrb->tail = rdrb->head + 1;
-        rdrb->lock = (pthread_mutex_t *) (rdrb->tail + 1);
-        rdrb->full = (pthread_cond_t *) (rdrb->lock + 1);
-        rdrb->healthy = rdrb->full + 1;
-        rdrb->api = (pid_t *) (rdrb->healthy + 1);
-
-        free(shm_rdrb_fn);
-
-        return rdrb;
+        return rdrb_create(O_RDWR);
 }
 
 int shm_rdrbuff_wait_full(struct shm_rdrbuff * rdrb,
@@ -315,14 +328,6 @@ int shm_rdrbuff_wait_full(struct shm_rdrbuff * rdrb,
         return 0;
 }
 
-void shm_rdrbuff_close(struct shm_rdrbuff * rdrb)
-{
-        assert(rdrb);
-
-        munmap(rdrb->shm_base, SHM_FILE_SIZE);
-        free(rdrb);
-}
-
 void shm_rdrbuff_purge(void)
 {
         char * shm_rdrb_fn;
@@ -335,27 +340,6 @@ void shm_rdrbuff_purge(void)
         free(shm_rdrb_fn);
 }
 
-void shm_rdrbuff_destroy(struct shm_rdrbuff * rdrb)
-{
-        char * shm_rdrb_fn;
-
-        assert(rdrb);
-
-        if (getpid() != *rdrb->api && kill(*rdrb->api, 0) == 0)
-                return;
-
-        munmap(rdrb->shm_base, SHM_FILE_SIZE);
-
-        shm_rdrb_fn = rdrb_filename();
-        if (shm_rdrb_fn == NULL)
-                return;
-
-        shm_unlink(shm_rdrb_fn);
-
-        free(rdrb);
-        free(shm_rdrb_fn);
-}
-
 ssize_t shm_rdrbuff_write(struct shm_rdrbuff * rdrb,
                           size_t               headspace,
                           size_t               tailspace,