Merge home and roaming stats file

Instead creating for each service two stats file (home and roaming), just
create one. Each entry in the file is marked with a flag (home or roaming).

The file header contains two additional index which points to the current
home or roaming entry.

Now we have a nice history in the ring buffer.
Additionally this reduces the number of open files by half.

diff --git a/src/stats.c b/src/stats.c
index 0ad8ae2..7d05b89 100644 (file)
--- a/src/stats.c
+++ b/src/stats.c
@@ -31,10 +31,11 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <string.h>
+#include <limits.h>
 
 #include "connman.h"
 
-#define MAGIC 0xFA00B915
+#define MAGIC 0xFA00B916
 
 /*
  * Statistics counters are stored into a ring buffer which is stored
@@ -45,20 +46,25 @@
  *   Initialy only the smallest possible amount of disk space is allocated
  *   The files grow to the configured maximal size
  *   The grows by _SC_PAGESIZE step size
- *   For each service home and service roaming counter set a file is created
+ *   For each service a file is created
  *   Each file has a header where the indexes are stored
  *
  * Entries properties:
- *   The entries are fixed sized (stats_record)
  *   Each entry has a timestamp
+ *   A flag to mark if the entry is either home (0) or roaming (1) entry
+ *   The entries are fixed sized (stats_record)
  *
  * Ring buffer properties:
- *   There are to indexes 'begin' and 'end'
+ *   There are to indexes 'begin', 'end', 'home' and 'roaming'
  *   'begin' points to the oldest entry
  *   'end' points to the newest/current entry
+ *   'home' points to the current home entry
+ *   'roaming' points to the current roaming entry
  *   If 'begin' == 'end' then the buffer is empty
  *   If 'end' + 1 == 'begin then it's full
  *   The ring buffer is valid in the range (begin, end]
+ *   If 'home' has the value UINT_MAX', 'home' is invalid
+ *   if 'roaming' has the value UINT_MAX', 'roaming' is invalid
  *   'first' points to the first entry in the ring buffer
  *   'last' points to the last entry in the ring buffer
  */
@@ -67,10 +73,13 @@ struct stats_file_header {
        unsigned int magic;
        unsigned int begin;
        unsigned int end;
+       unsigned int home;
+       unsigned int roaming;
 };
 
 struct stats_record {
        time_t ts;
+       unsigned int roaming;
        struct connman_stats_data data;
 };
 
@@ -84,11 +93,8 @@ struct stats_file {
        /* cached values */
        struct stats_record *first;
        struct stats_record *last;
-};
-
-struct stats_handle {
-       struct stats_file home;
-       struct stats_file roaming;
+       struct stats_record *home;
+       struct stats_record *roaming;
 };
 
 GHashTable *stats_hash = NULL;
@@ -112,6 +118,30 @@ static struct stats_record *get_end(struct stats_file *file)
        return (struct stats_record *)(file->addr + off);
 }
 
+static struct stats_record *get_home(struct stats_file *file)
+{
+       struct stats_file_header *hdr;
+
+       hdr = get_hdr(file);
+
+       if (hdr->home == UINT_MAX)
+               return NULL;
+
+       return (struct stats_record *)(file->addr + hdr->home);
+}
+
+static struct stats_record *get_roaming(struct stats_file *file)
+{
+       struct stats_file_header *hdr;
+
+       hdr = get_hdr(file);
+
+       if (hdr->roaming == UINT_MAX)
+               return NULL;
+
+       return (struct stats_record *)(file->addr + hdr->roaming);
+}
+
 static void set_begin(struct stats_file *file, struct stats_record *begin)
 {
        struct stats_file_header *hdr;
@@ -128,6 +158,22 @@ static void set_end(struct stats_file *file, struct stats_record *end)
        hdr->end = (char *)end - file->addr;
 }
 
+static void set_home(struct stats_file *file, struct stats_record *home)
+{
+       struct stats_file_header *hdr;
+
+       hdr = get_hdr(file);
+       hdr->home = (char *)home - file->addr;
+}
+
+static void set_roaming(struct stats_file *file, struct stats_record *roaming)
+{
+       struct stats_file_header *hdr;
+
+       hdr = get_hdr(file);
+       hdr->roaming = (char *)roaming - file->addr;
+}
+
 static struct stats_record *get_next(struct stats_file *file,
                                        struct stats_record *cur)
 {
@@ -139,21 +185,10 @@ static struct stats_record *get_next(struct stats_file *file,
        return cur;
 }
 
-static struct stats_file *stats_file_get(struct stats_handle *handle,
-                                               connman_bool_t roaming)
+static void stats_free(gpointer user_data)
 {
-       struct stats_file *file;
+       struct stats_file *file = user_data;
 
-       if (roaming == FALSE)
-               file = &handle->home;
-       else
-               file = &handle->roaming;
-
-       return file;
-}
-
-static void stats_close_file(struct stats_file *file)
-{
        msync(file->addr, file->len, MS_SYNC);
 
        munmap(file->addr, file->len);
@@ -163,27 +198,18 @@ static void stats_close_file(struct stats_file *file)
        file->fd = -1;
 
        g_free(file->name);
-}
-
-static void stats_free(gpointer user_data)
-{
-       struct stats_handle *handle = user_data;
-
-       stats_close_file(&handle->home);
-       stats_close_file(&handle->roaming);
-
-       g_free(handle);
+       g_free(file);
 }
 
 static int stats_create(struct connman_service *service)
 {
-       struct stats_handle *handle;
+       struct stats_file *file;
 
-       handle = g_try_new0(struct stats_handle, 1);
-       if (handle == NULL)
+       file = g_try_new0(struct stats_file, 1);
+       if (file == NULL)
                return -ENOMEM;
 
-       g_hash_table_insert(stats_hash, service, handle);
+       g_hash_table_insert(stats_hash, service, file);
 
        return 0;
 }
@@ -203,10 +229,22 @@ static void update_last(struct stats_file *file)
        file->last = file->first + max_entries - 1;
 }
 
+static void update_home(struct stats_file *file)
+{
+       file->home = get_home(file);
+}
+
+static void update_roaming(struct stats_file *file)
+{
+       file->roaming = get_roaming(file);
+}
+
 static void stats_file_update_cache(struct stats_file *file)
 {
        update_first(file);
        update_last(file);
+       update_home(file);
+       update_roaming(file);
 }
 
 static int stats_file_remap(struct stats_file *file, size_t size)
@@ -246,26 +284,17 @@ static int stats_file_remap(struct stats_file *file, size_t size)
        return 0;
 }
 
-static int stats_open_file(struct connman_service *service,
-                               struct stats_file *file,
-                               connman_bool_t roaming)
+static int stats_open(struct connman_service *service,
+                       struct stats_file *file)
 {
        struct stat st;
-       char *name;
        int err;
        size_t size;
        struct stats_file_header *hdr;
        connman_bool_t new_file = FALSE;
 
-       if (roaming == FALSE) {
-               name = g_strdup_printf("%s/stats/%s.data", STORAGEDIR,
-                                       __connman_service_get_ident(service));
-       } else {
-               name = g_strdup_printf("%s/stats/%s-roaming.data", STORAGEDIR,
-                                       __connman_service_get_ident(service));
-       }
-
-       file->name = name;
+       file->name = g_strdup_printf("%s/stats/%s.data", STORAGEDIR,
+                       __connman_service_get_ident(service));
 
        err = stat(file->name, &st);
        if (err < 0) {
@@ -274,7 +303,7 @@ static int stats_open_file(struct connman_service *service,
                new_file = TRUE;
        }
 
-       file->fd = open(name, O_RDWR | O_CREAT, 0644);
+       file->fd = open(file->name, O_RDWR | O_CREAT, 0644);
 
        if (file->fd < 0) {
                connman_error("open error %s for %s",
@@ -298,6 +327,8 @@ static int stats_open_file(struct connman_service *service,
        if (hdr->magic != MAGIC ||
                        hdr->begin < sizeof(struct stats_file_header) ||
                        hdr->end < sizeof(struct stats_file_header) ||
+                       hdr->home < sizeof(struct stats_file_header) ||
+                       hdr->roaming < sizeof(struct stats_file_header) ||
                        hdr->begin > file->len ||
                        hdr->end > file->len) {
                if (new_file == FALSE) {
@@ -313,47 +344,35 @@ static int stats_open_file(struct connman_service *service,
                hdr->magic = MAGIC;
                hdr->begin = sizeof(struct stats_file_header);
                hdr->end = sizeof(struct stats_file_header);
-       }
+               hdr->home = UINT_MAX;
+               hdr->roaming = UINT_MAX;
 
-       return 0;
-}
-
-static int stats_open(struct connman_service *service,
-                       struct stats_handle *handle)
-{
-       int err;
-
-       err = stats_open_file(service, &handle->home, FALSE);
-       if (err < 0)
-               return err;
-
-       err = stats_open_file(service, &handle->roaming, TRUE);
-       if (err < 0)
-               return err;
+               stats_file_update_cache(file);
+       }
 
        return 0;
 }
 
 int __connman_stats_service_register(struct connman_service *service)
 {
-       struct stats_handle *handle;
+       struct stats_file *file;
        int err;
 
        DBG("service %p", service);
 
-       handle = g_hash_table_lookup(stats_hash, service);
-       if (handle == NULL) {
+       file = g_hash_table_lookup(stats_hash, service);
+       if (file == NULL) {
                err = stats_create(service);
 
                if (err < 0)
                        return err;
 
-               handle = g_hash_table_lookup(stats_hash, service);
+               file = g_hash_table_lookup(stats_hash, service);
        } else {
                return -EALREADY;
        }
 
-       err = stats_open(service, handle);
+       err = stats_open(service, file);
        if (err < 0)
                g_hash_table_remove(stats_hash, service);
 
@@ -371,17 +390,14 @@ int  __connman_stats_update(struct connman_service *service,
                                connman_bool_t roaming,
                                struct connman_stats_data *data)
 {
-       struct stats_handle *handle;
        struct stats_file *file;
        struct stats_record *next;
        int err;
 
-       handle = g_hash_table_lookup(stats_hash, service);
-       if (handle == NULL)
+       file = g_hash_table_lookup(stats_hash, service);
+       if (file == NULL)
                return -EEXIST;
 
-       file = stats_file_get(handle, roaming);
-
        if (file->len < file->max_len &&
                        file->last == get_end(file)) {
                DBG("grow file %s", file->name);
@@ -397,8 +413,14 @@ int  __connman_stats_update(struct connman_service *service,
                set_begin(file, get_next(file, next));
 
        next->ts = time(NULL);
+       next->roaming = roaming;
        memcpy(&next->data, data, sizeof(struct connman_stats_data));
 
+       if (roaming != TRUE)
+               set_home(file, next);
+       else
+               set_roaming(file, next);
+
        set_end(file, next);
 
        return 0;
@@ -408,19 +430,20 @@ int __connman_stats_get(struct connman_service *service,
                                connman_bool_t roaming,
                                struct connman_stats_data *data)
 {
-       struct stats_handle *handle;
        struct stats_file *file;
-       struct stats_file_header *hdr;
+       struct stats_record *rec;
 
-       handle = g_hash_table_lookup(stats_hash, service);
-       if (handle == NULL)
+       file = g_hash_table_lookup(stats_hash, service);
+       if (file == NULL)
                return -EEXIST;
 
-       file = stats_file_get(handle, roaming);
-       hdr = get_hdr(file);
+       if (roaming != TRUE)
+               rec = file->home;
+       else
+               rec = file->roaming;
 
-       if (hdr->begin != hdr->end) {
-               memcpy(data, &get_end(file)->data,
+       if (rec != NULL) {
+               memcpy(data, &rec->data,
                        sizeof(struct connman_stats_data));
        }