nvram: handle nvram at varying offsets within the eraseblock (fixes Edimax PS-1208mfg...

[openwrt/staging/florian.git] / package / nvram / src / nvram.c

diff --git a/package/nvram/src/nvram.c b/package/nvram/src/nvram.c
index 7ab8c81ab0c489616af66aaa2ce2a3f0a07fcc7e..a0bc006d15322540978f6496c98f8c360ab7d0dd 100644 (file)
--- a/package/nvram/src/nvram.c
+++ b/package/nvram/src/nvram.c
@@ -142,7 +142,7 @@ static int _nvram_rehash(nvram_handle_t *h)
 /* Get nvram header. */
 nvram_header_t * nvram_header(nvram_handle_t *h)
 {
-       return (nvram_header_t *) &h->mmap[NVRAM_START(nvram_erase_size)];
+       return (nvram_header_t *) &h->mmap[h->offset];
 }
 
 /* Get the value of an NVRAM variable. */
@@ -337,10 +337,12 @@ int nvram_commit(nvram_handle_t *h)
 /* Open NVRAM and obtain a handle. */
 nvram_handle_t * nvram_open(const char *file, int rdonly)
 {
+       int i;
        int fd;
        char *mtd = NULL;
        nvram_handle_t *h;
        nvram_header_t *header;
+       int offset = -1;
 
        /* If erase size or file are undefined then try to define them */
        if( (nvram_erase_size == 0) || (file == NULL) )
@@ -361,15 +363,28 @@ nvram_handle_t * nvram_open(const char *file, int rdonly)
 
                if( mmap_area != MAP_FAILED )
                {
-                       memset(mmap_area, 0xFF, NVRAM_START(nvram_erase_size));
+                       for( i = 0; i <= ((nvram_erase_size - NVRAM_SPACE) / sizeof(uint32_t)); i++ )
+                       {
+                               if( ((uint32_t *)mmap_area)[i] == NVRAM_MAGIC )
+                               {
+                                       offset = i * sizeof(uint32_t);
+                                       break;
+                               }
+                       }
 
-                       if((h = (nvram_handle_t *) malloc(sizeof(nvram_handle_t))) != NULL)
+                       if( offset < 0 )
+                       {
+                               free(mtd);
+                               return NULL;
+                       }
+                       else if( (h = malloc(sizeof(nvram_handle_t))) != NULL )
                        {
                                memset(h, 0, sizeof(nvram_handle_t));
 
                                h->fd     = fd;
                                h->mmap   = mmap_area;
                                h->length = nvram_erase_size;
+                               h->offset = offset;
 
                                header = nvram_header(h);