From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gummerer Subject: [PATCH 02/22] read-cache: split index file version specific functionality Date: Sun, 7 Jul 2013 10:11:40 +0200 Message-ID: <1373184720-29767-3-git-send-email-t.gummerer@gmail.com> References: <1373184720-29767-1-git-send-email-t.gummerer@gmail.com> Cc: trast@inf.ethz.ch, mhagger@alum.mit.edu, gitster@pobox.com, pclouds@gmail.com, robin.rosenberg@dewire.com, t.gummerer@gmail.com To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Sun Jul 07 10:12:55 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Uvk5W-0005m8-4d for gcvg-git-2@plane.gmane.org; Sun, 07 Jul 2013 10:12:54 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751872Ab3GGIMv (ORCPT ); Sun, 7 Jul 2013 04:12:51 -0400 Received: from mail-ee0-f48.google.com ([74.125.83.48]:38666 "EHLO mail-ee0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745Ab3GGIMa (ORCPT ); Sun, 7 Jul 2013 04:12:30 -0400 Received: by mail-ee0-f48.google.com with SMTP id b47so2136508eek.21 for ; Sun, 07 Jul 2013 01:12:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=GgbEcCAgnjhcnQAtqS5+wT0MdlM7p47I9NYTXt0zqQM=; b=kwNaP69CxkOuA28PylFONUHmkazB4JCSy52eiyux+v6faKmLXlNtcB0hJLNIjCQJAY BVNYme27+EtenZySI/pkjKIBBkZosctSd+ZKNZs7inQ3bRfj5EJezX/km0Ewb9NSBB4b lFyjQKpOTwuo9p4x7Ek20jumrY9L03NoZmnIffaL+WxsKgA7QqYk28Lyulnl7OsRkg86 OrHW7FOgQlZpOt/qXF1WqIE9vGA31ER6OykiGuFBoWBbyFhClJ3CdQqrzoGuq1nTnBpE wf+oH90rr6x60YydeZ3nCxRbEW0M/GjtxzQ5qnAd5mUVqqVhF9c25k/8lUKXBCr5cyqv a20g== X-Received: by 10.14.173.130 with SMTP id v2mr19753159eel.29.1373184749021; Sun, 07 Jul 2013 01:12:29 -0700 (PDT) Received: from localhost (host252-23-dynamic.0-87-r.retail.telecomitalia.it. [87.0.23.252]) by mx.google.com with ESMTPSA id b3sm30703119eev.10.2013.07.07.01.12.26 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Sun, 07 Jul 2013 01:12:28 -0700 (PDT) X-Mailer: git-send-email 1.8.3.453.g1dfc63d In-Reply-To: <1373184720-29767-1-git-send-email-t.gummerer@gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Split index file version specific functionality to their own functions, to prepare for moving the index file version specific parts to their own file. This makes it easier to add a new index file format later. Signed-off-by: Thomas Gummerer --- cache.h | 5 +- read-cache.c | 130 +++++++++++++++++++++++++++++++++------------------ test-index-version.c | 2 +- 3 files changed, 90 insertions(+), 47 deletions(-) diff --git a/cache.h b/cache.h index c288678..7af853b 100644 --- a/cache.h +++ b/cache.h @@ -100,9 +100,12 @@ unsigned long git_deflate_bound(git_zstream *, unsigned long); */ #define CACHE_SIGNATURE 0x44495243 /* "DIRC" */ -struct cache_header { +struct cache_version_header { unsigned int hdr_signature; unsigned int hdr_version; +}; + +struct cache_header { unsigned int hdr_entries; }; diff --git a/read-cache.c b/read-cache.c index d5201f9..93947bf 100644 --- a/read-cache.c +++ b/read-cache.c @@ -1268,10 +1268,8 @@ 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_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)) @@ -1279,10 +1277,22 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size) hdr_version = ntohl(hdr->hdr_version); if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version) return error("bad index version %d", hdr_version); + return 0; +} + +static int verify_hdr(void *mmap, unsigned long size) +{ + git_SHA_CTX c; + unsigned char sha1[20]; + + if (size < sizeof(struct cache_version_header) + + sizeof(struct cache_header) + 20) + die("index file smaller than expected"); + git_SHA1_Init(&c); - git_SHA1_Update(&c, hdr, size - 20); + git_SHA1_Update(&c, mmap, size - 20); git_SHA1_Final(sha1, &c); - if (hashcmp(sha1, (unsigned char *)hdr + size - 20)) + if (hashcmp(sha1, (unsigned char *)mmap + size - 20)) return error("bad index file sha1 signature"); return 0; } @@ -1424,47 +1434,19 @@ 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) +static int read_index_v2(struct index_state *istate, void *mmap, unsigned long mmap_size) { - int fd, i; - struct stat st; + int i; unsigned long src_offset; - struct cache_header *hdr; - void *mmap; - size_t mmap_size; + struct cache_version_header *hdr; + struct cache_header *hdr_v2; struct strbuf previous_name_buf = STRBUF_INIT, *previous_name; - if (istate->initialized) - return istate->cache_nr; - - 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"); - - mmap_size = xsize_t(st.st_size); - if (mmap_size < sizeof(struct cache_header) + 20) - die("index file smaller than expected"); - - mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); - if (mmap == MAP_FAILED) - die_errno("unable to map index file"); - close(fd); - hdr = mmap; - if (verify_hdr(hdr, mmap_size) < 0) - goto unmap; + hdr_v2 = (struct cache_header *)((char *)mmap + sizeof(*hdr)); istate->version = ntohl(hdr->hdr_version); - istate->cache_nr = ntohl(hdr->hdr_entries); + istate->cache_nr = ntohl(hdr_v2->hdr_entries); istate->cache_alloc = alloc_nr(istate->cache_nr); istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache)); istate->initialized = 1; @@ -1474,7 +1456,7 @@ int read_index_from(struct index_state *istate, const char *path) else previous_name = NULL; - src_offset = sizeof(*hdr); + src_offset = sizeof(*hdr) + sizeof(*hdr_v2); for (i = 0; i < istate->cache_nr; i++) { struct ondisk_cache_entry *disk_ce; struct cache_entry *ce; @@ -1487,8 +1469,6 @@ 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, @@ -1508,6 +1488,58 @@ int read_index_from(struct index_state *istate, const char *path) src_offset += 8; src_offset += extsize; } + return 0; +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_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(mmap, 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; @@ -1771,10 +1803,11 @@ void update_index_if_able(struct index_state *istate, struct lock_file *lockfile rollback_lock_file(lockfile); } -int write_index(struct index_state *istate, int newfd) +static int write_index_v2(struct index_state *istate, int newfd) { git_SHA_CTX c; - struct cache_header hdr; + struct cache_version_header hdr; + struct cache_header hdr_v2; int i, err, removed, extended, hdr_version; struct cache_entry **cache = istate->cache; int entries = istate->cache_nr; @@ -1804,11 +1837,13 @@ int write_index(struct index_state *istate, int newfd) hdr.hdr_signature = htonl(CACHE_SIGNATURE); hdr.hdr_version = htonl(hdr_version); - hdr.hdr_entries = htonl(entries - removed); + hdr_v2.hdr_entries = htonl(entries - removed); git_SHA1_Init(&c); if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0) return -1; + if (ce_write(&c, newfd, &hdr_v2, sizeof(hdr_v2)) < 0) + return -1; previous_name = (hdr_version == 4) ? &previous_name_buf : NULL; for (i = 0; i < entries; i++) { @@ -1854,6 +1889,11 @@ int write_index(struct index_state *istate, int newfd) return 0; } +int write_index(struct index_state *istate, int newfd) +{ + return write_index_v2(istate, newfd); +} + /* * Read the index file that is potentially unmerged into given * index_state, dropping any unmerged entries. Returns true if diff --git a/test-index-version.c b/test-index-version.c index 05d4699..4c0386f 100644 --- a/test-index-version.c +++ b/test-index-version.c @@ -2,7 +2,7 @@ int main(int argc, char **argv) { - struct cache_header hdr; + struct cache_version_header hdr; int version; memset(&hdr,0,sizeof(hdr)); -- 1.8.3.453.g1dfc63d