index: mmap: open and close file

diff --git a/libkmod/libkmod-index.c b/libkmod/libkmod-index.c
index a0f9e0b..c078524 100644 (file)
--- a/libkmod/libkmod-index.c
+++ b/libkmod/libkmod-index.c
@@ -506,3 +506,91 @@ struct index_value *index_searchwild(struct index_file *in, const char *key)
        buf_destroy(buf);
        return out;
 }
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/**************************************************************************/
+/*
+ * Alternative implementation, using mmap to map all the file to memory when
+ * starting
+ */
+struct index_mm {
+       struct kmod_ctx *ctx;
+       void *mm;
+       uint32_t root_offset;
+       size_t size;
+};
+
+struct index_mm *index_mm_open(struct kmod_ctx *ctx, const char *filename)
+{
+       int fd;
+       struct stat st;
+       struct index_mm *idx;
+       struct {
+               uint32_t magic;
+               uint32_t version;
+               uint32_t root_offset;
+       } hdr;
+       void *p;
+
+       DBG(ctx, "file=%s\n", filename);
+
+       if ((fd = open(filename, O_RDONLY)) < 0) {
+               ERR(ctx, "%m\n");
+               return NULL;
+       }
+
+       fstat(fd, &st);
+
+       idx = malloc(sizeof(*idx));
+       if (idx == NULL) {
+               ERR(ctx, "%m\n");
+               goto fail;
+       }
+
+       if ((idx->mm = mmap(0, st.st_size, PROT_READ,
+                               MAP_PRIVATE | MAP_POPULATE,
+                               fd, 0)) == MAP_FAILED) {
+               ERR(ctx, "%m\n");
+               goto fail;
+       }
+
+       p = idx->mm;
+       hdr.magic = read_long_mm(&p);
+       hdr.version = read_long_mm(&p);
+       hdr.root_offset = read_long_mm(&p);
+
+       if (hdr.magic != INDEX_MAGIC) {
+               ERR(ctx, "magic check fail: %x instead of %x\n", hdr.magic,
+                                                               INDEX_MAGIC);
+               goto fail;
+       }
+
+       if (hdr.version >> 16 != INDEX_VERSION_MAJOR) {
+               ERR(ctx, "major version check fail: %u instead of %u\n",
+                                               hdr.version, INDEX_MAGIC);
+               goto fail;
+       }
+
+       idx->root_offset = hdr.root_offset;
+       idx->size = st.st_size;
+       idx->ctx = ctx;
+       close(fd);
+
+       return idx;
+
+fail:
+       close(fd);
+       if (idx->mm)
+               munmap(idx->mm, st.st_size);
+       free(idx);
+       return NULL;
+}
+
+void index_mm_close(struct index_mm *idx)
+{
+       munmap(idx->mm, idx->size);
+       free(idx);
+}

diff --git a/libkmod/libkmod-index.h b/libkmod/libkmod-index.h
index 653ce42..e611eee 100644 (file)
--- a/libkmod/libkmod-index.h
+++ b/libkmod/libkmod-index.h
@@ -162,4 +162,9 @@ struct index_value *index_searchwild(struct index_file *idx, const char *key);
 
 void index_values_free(struct index_value *values);
 
+/* Implementation using mmap */
+struct index_mm;
+struct index_mm *index_mm_open(struct kmod_ctx *ctx, const char *filename);
+void index_mm_close(struct index_mm *index);
+
 #endif