consistently check OOM from hash_initialize/hash_insert

Both hash_initialize and hash_insert may return NULL to indicate
allocation errors.  So implement a mog_oom_if_null helper function to
destroy the process instead of attempting to continue and dereferencing
NULL pointers.

This may affect configurations with limited memory and lacking
overcommit; but is unlikely to trigger given the small memory footprint
of cmogstored.

10 files changed, 19 insertions, 16 deletions

diff --git a/alloc.c b/alloc.c
index 5afcee2..f5ce8bc 100644
--- a/alloc.c
+++ b/alloc.c
@@ -58,6 +58,11 @@ _Noreturn void mog_oom(void)
         abort();
 }
 
+void mog_oom_if_null(const void *ptr)
+{
+        if (!ptr)
+                mog_oom();
+}
 
 /*
  * Cache alignment is important for sub-pagesized allocations
diff --git a/cfg.c b/cfg.c
index c689aa3..a87500f 100644
--- a/cfg.c
+++ b/cfg.c
@@ -53,8 +53,7 @@ static void cfg_atexit(void)
 __attribute__((constructor)) static void cfg_init(void)
 {
         all_cfg = hash_initialize(7, NULL, cfg_hash, cfg_cmp, cfg_free);
-        if (!all_cfg)
-                mog_oom();
+        mog_oom_if_null(all_cfg);
 
         atexit(cfg_atexit);
 }
diff --git a/cmogstored.h b/cmogstored.h
index d9e74fc..0b5a7bf 100644
--- a/cmogstored.h
+++ b/cmogstored.h
@@ -310,6 +310,7 @@ void mog_rbuf_free(struct mog_rbuf *);
 void mog_rbuf_free_and_null(struct mog_rbuf **);
 void *mog_fsbuf_get(size_t *size);
 void mog_alloc_quit(void);
+void mog_oom_if_null(const void *);
 
 #define die_errno(...) do { \
         error(EXIT_FAILURE, errno, __VA_ARGS__); \
diff --git a/fsck_queue.c b/fsck_queue.c
index 22f3d38..c99a9ed 100644
--- a/fsck_queue.c
+++ b/fsck_queue.c
@@ -37,6 +37,7 @@ static void fsck_queue_atexit(void)
 MOG_NOINLINE static void fsck_queue_once(void)
 {
         fsck_queues = hash_initialize(7, NULL, fq_hash, fq_cmp, free);
+        mog_oom_if_null(fsck_queues);
         atexit(fsck_queue_atexit);
 }
 
diff --git a/inherit.c b/inherit.c
index da3c852..75d3050 100644
--- a/inherit.c
+++ b/inherit.c
@@ -131,8 +131,7 @@ void mog_inherit_init(void)
                 return;
 
         listeners = hash_initialize(3, NULL, listener_hash, listener_cmp, free);
-        if (!listeners)
-                die("failed to initialize inherited listeners hash");
+        mog_oom_if_null(listeners);
         atexit(listeners_cleanup);
 
         fds = xstrdup(orig);
diff --git a/ioutil.c b/ioutil.c
index 9323a32..fdb9562 100644
--- a/ioutil.c
+++ b/ioutil.c
@@ -39,8 +39,7 @@ __attribute__((destructor)) static void iou_destructor(void)
 __attribute__((constructor)) static void iou_constructor(void)
 {
         dev_iou = hash_initialize(7, NULL, iou_hash, iou_cmp, free);
-        if (!dev_iou)
-                mog_oom();
+        mog_oom_if_null(dev_iou);
 }
 
 static bool cleanup_begin_i(void *ent, void *unused)
diff --git a/mnt.c b/mnt.c
index 7205c2c..8349214 100644
--- a/mnt.c
+++ b/mnt.c
@@ -62,8 +62,8 @@ static Hash_table * mnt_new(size_t n)
 {
         Hash_table *rv = hash_initialize(n, NULL, me_hash, me_cmp, me_free);
 
-        if (!rv)
-                mog_oom();
+        mog_oom_if_null(rv);
+
         return rv;
 }
 
diff --git a/process.c b/process.c
index e817fba..28615df 100644
--- a/process.c
+++ b/process.c
@@ -38,8 +38,7 @@ void mog_process_init(size_t nr)
         if (nr < 3)
                 nr = 3;
         processes = hash_initialize(nr, NULL, process_hash, process_cmp, free);
-        if (processes == NULL)
-                mog_oom();
+        mog_oom_if_null(processes);
 }
 
 void mog_process_reset(void)
@@ -123,8 +122,7 @@ void mog_process_register(pid_t pid, unsigned id)
         p->pid = pid;
         p->id = id;
 
-        if (hash_insert(processes, p) == NULL)
-                mog_oom();
+        mog_oom_if_null(hash_insert(processes, p));
 }
 
 /*
diff --git a/svc.c b/svc.c
index 6eea3e3..e9d8d6d 100644
--- a/svc.c
+++ b/svc.c
@@ -50,8 +50,7 @@ static void svc_atexit(void) /* called atexit */
 static void svc_once(void)
 {
         by_docroot = hash_initialize(7, NULL, svc_hash, svc_cmp, svc_free);
-        if (!by_docroot)
-                mog_oom();
+        mog_oom_if_null(by_docroot);
 
         mog_umask = umask(0);
         umask(mog_umask);
@@ -98,6 +97,7 @@ struct mog_svc * mog_svc_new(const char *docroot)
         CHECK(int, 0, pthread_mutex_init(&svc->by_mog_devid_lock, NULL));
         svc->by_mog_devid = hash_initialize(7, NULL, mog_dev_hash,
                                         mog_dev_cmp, free);
+        mog_oom_if_null(svc->by_mog_devid);
 
         switch (hash_insert_if_absent(by_docroot, svc, NULL)) {
         case 0:
diff --git a/svc_dev.c b/svc_dev.c
index d7e1dcd..e8d8a2c 100644
--- a/svc_dev.c
+++ b/svc_dev.c
@@ -52,6 +52,8 @@ static struct mog_devlist * mog_devlist_new(dev_t st_dev)
                                                 */
                                                NULL);
 
+        mog_oom_if_null(devlist->by_mogdevid);
+
         return devlist;
 }
 
@@ -90,8 +92,7 @@ static void svc_init_dev_hash(struct mog_svc *svc)
 
         svc->by_st_dev = hash_initialize(7, NULL, devlist_hash,
                                          devlist_cmp, devlist_free);
-        if (!svc->by_st_dev)
-                mog_oom();
+        mog_oom_if_null(svc->by_st_dev);
 }
 
 static int svc_scandev(struct mog_svc *svc, size_t *nr, mog_scandev_cb cb)