Modify the read_index_from function, splitting it up into
one function that stays the same for every index format,
doing the basic operations such as verifying the header,
and a function which is specific for each index version,
which does the real reading of the index.
Signed-off-by: Thomas Gummerer <t.gummerer@xxxxxxxxx>
---
cache.h | 1 +
read-cache.c | 108 +++++++++++++++++++++++++++++++++++------------------------
2 files changed, 66 insertions(+), 43 deletions(-)
diff --git a/cache.h b/cache.h
index d4028ef..3aa70d8 100644
--- a/cache.h
+++ b/cache.h
@@ -435,6 +435,7 @@ extern int init_db(const char *template_dir, unsigned int flags);
/* Initialize and use the cache information */
extern int read_index(struct index_state *);
extern int read_index_preload(struct index_state *, const char **pathspec);
+extern void read_index_v2(struct index_state *, void *mmap, int);
extern int read_index_from(struct index_state *, const char *path);
extern int is_index_unborn(struct index_state *);
extern int read_index_unmerged(struct index_state *);
diff --git a/read-cache.c b/read-cache.c
index c44b5f7..3d83f05 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1247,10 +1247,8 @@ struct ondisk_cache_entry_extended {
ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
ondisk_cache_entry_size(ce_namelen(ce)))
-static int verify_hdr(struct cache_version_header *hdr, unsigned long size)
+static int verify_hdr_version(struct cache_version_header *hdr, unsigned long size)
{
- git_SHA_CTX c;
- unsigned char sha1[20];
int hdr_version;
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
@@ -1258,6 +1256,14 @@ static int verify_hdr(struct cache_version_header *hdr, unsigned long size)
hdr_version = ntohl(hdr->hdr_version);
if (hdr_version < 2 || 4 < hdr_version)
return error("bad index version %d", hdr_version);
+ return 0;
+}
+
+static int verify_hdr_v2(struct cache_version_header *hdr, unsigned long size)
+{
+ git_SHA_CTX c;
+ unsigned char sha1[20];
+
git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20);
git_SHA1_Final(sha1, &c);
@@ -1403,50 +1409,15 @@ static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
return ce;
}
-/* remember to discard_cache() before reading a different cache! */
-int read_index_from(struct index_state *istate, const char *path)
+void read_index_v2(struct index_state *istate, void *mmap, int mmap_size)
{
- int fd, i;
- struct stat st;
+ int i;
unsigned long src_offset;
struct cache_version_header *hdr;
struct cache_header_v2 *hdr_v2;
- void *mmap;
- size_t mmap_size;
struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
- errno = EBUSY;
- if (istate->initialized)
- return istate->cache_nr;
-
- errno = ENOENT;
- istate->timestamp.sec = 0;
- istate->timestamp.nsec = 0;
- fd = open(path, O_RDONLY);
- if (fd < 0) {
- if (errno == ENOENT)
- return 0;
- die_errno("index file open failed");
- }
-
- if (fstat(fd, &st))
- die_errno("cannot stat the open index");
-
- errno = EINVAL;
- mmap_size = xsize_t(st.st_size);
- if (mmap_size < sizeof(struct cache_version_header) + 20)
- die("index file smaller than expected");
-
- mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
- close(fd);
- if (mmap == MAP_FAILED)
- die_errno("unable to map index file");
-
hdr = mmap;
- hdr_v2 = mmap + sizeof(*hdr);
- if (verify_hdr(hdr, mmap_size) < 0)
- goto unmap;
-
hdr_v2 = mmap + sizeof(*hdr);
istate->version = ntohl(hdr->hdr_version);
istate->cache_nr = ntohl(hdr_v2->hdr_entries);
@@ -1472,8 +1443,6 @@ int read_index_from(struct index_state *istate, const char *path)
src_offset += consumed;
}
strbuf_release(&previous_name_buf);
- istate->timestamp.sec = st.st_mtime;
- istate->timestamp.nsec = ST_MTIME_NSEC(st);
while (src_offset <= mmap_size - 20 - 8) {
/* After an array of active_nr index entries,
@@ -1493,12 +1462,65 @@ int read_index_from(struct index_state *istate, const char *path)
src_offset += 8;
src_offset += extsize;
}
+ return;
+unmap:
+ munmap(mmap, mmap_size);
+ die("index file corrupt");
+}
+
+/* remember to discard_cache() before reading a different cache! */
+int read_index_from(struct index_state *istate, const char *path)
+{
+ int fd;
+ struct stat st;
+ struct cache_version_header *hdr;
+ void *mmap;
+ size_t mmap_size;
+
+ errno = EBUSY;
+ if (istate->initialized)
+ return istate->cache_nr;
+
+ errno = ENOENT;
+ istate->timestamp.sec = 0;
+ istate->timestamp.nsec = 0;
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ return 0;
+ die_errno("index file open failed");
+ }
+
+ if (fstat(fd, &st))
+ die_errno("cannot stat the open index");
+
+ errno = EINVAL;
+ mmap_size = xsize_t(st.st_size);
+ if (mmap_size < sizeof(struct cache_version_header) + 20)
+ die("index file smaller than expected");
+
+ mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+ close(fd);
+ if (mmap == MAP_FAILED)
+ die_errno("unable to map index file");
+
+ hdr = mmap;
+ if (verify_hdr_version(hdr, mmap_size) < 0)
+ goto unmap;
+
+ if (verify_hdr_v2(hdr, mmap_size) < 0)
+ goto unmap;
+
+ read_index_v2(istate, mmap, mmap_size);
+
+ istate->timestamp.sec = st.st_mtime;
+ istate->timestamp.nsec = ST_MTIME_NSEC(st);
+
munmap(mmap, mmap_size);
return istate->cache_nr;
unmap:
munmap(mmap, mmap_size);
- errno = EINVAL;
die("index file corrupt");
}
--
1.7.10.886.gdf6792c.dirty
--
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