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-rw-r--r--builtin/index-pack.c2
-rw-r--r--cache.h3
-rw-r--r--compat/mmap.c4
-rw-r--r--git-compat-util.h1
-rw-r--r--read-cache.c47
-rw-r--r--wrapper.c38
6 files changed, 90 insertions, 5 deletions
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 54b089542b..18f57de58b 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -554,7 +554,7 @@ static void *unpack_data(struct object_entry *obj,
do {
ssize_t n = (len < 64*1024) ? len : 64*1024;
- n = pread(get_thread_data()->pack_fd, inbuf, n, from);
+ n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
if (n < 0)
die_errno(_("cannot pread pack file"));
if (!n)
diff --git a/cache.h b/cache.h
index 107ac61b68..cc46be4e0f 100644
--- a/cache.h
+++ b/cache.h
@@ -279,6 +279,7 @@ struct index_state {
initialized : 1;
struct hashmap name_hash;
struct hashmap dir_hash;
+ unsigned char sha1[20];
};
extern struct index_state the_index;
@@ -1322,6 +1323,8 @@ extern void fsync_or_die(int fd, const char *);
extern ssize_t read_in_full(int fd, void *buf, size_t count);
extern ssize_t write_in_full(int fd, const void *buf, size_t count);
+extern ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset);
+
static inline ssize_t write_str_in_full(int fd, const char *str)
{
return write_in_full(fd, str, strlen(str));
diff --git a/compat/mmap.c b/compat/mmap.c
index c9d46d1742..7f662fef7b 100644
--- a/compat/mmap.c
+++ b/compat/mmap.c
@@ -14,7 +14,7 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
}
while (n < length) {
- ssize_t count = pread(fd, (char *)start + n, length - n, offset + n);
+ ssize_t count = xpread(fd, (char *)start + n, length - n, offset + n);
if (count == 0) {
memset((char *)start+n, 0, length-n);
@@ -22,8 +22,6 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
}
if (count < 0) {
- if (errno == EAGAIN || errno == EINTR)
- continue;
free(start);
errno = EACCES;
return MAP_FAILED;
diff --git a/git-compat-util.h b/git-compat-util.h
index f6d3a46622..e6a4159a25 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -531,6 +531,7 @@ extern void *xcalloc(size_t nmemb, size_t size);
extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
extern ssize_t xread(int fd, void *buf, size_t len);
extern ssize_t xwrite(int fd, const void *buf, size_t len);
+extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
extern int xdup(int fd);
extern FILE *xfdopen(int fd, const char *mode);
extern int xmkstemp(char *template);
diff --git a/read-cache.c b/read-cache.c
index ba13353b37..7f5645e745 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1477,6 +1477,7 @@ int read_index_from(struct index_state *istate, const char *path)
if (verify_hdr(hdr, mmap_size) < 0)
goto unmap;
+ hashcpy(istate->sha1, (unsigned char *)hdr + mmap_size - 20);
istate->version = ntohl(hdr->hdr_version);
istate->cache_nr = ntohl(hdr->hdr_entries);
istate->cache_alloc = alloc_nr(istate->cache_nr);
@@ -1760,6 +1761,50 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce,
return result;
}
+/*
+ * This function verifies if index_state has the correct sha1 of the
+ * index file. Don't die if we have any other failure, just return 0.
+ */
+static int verify_index_from(const struct index_state *istate, const char *path)
+{
+ int fd;
+ ssize_t n;
+ struct stat st;
+ unsigned char sha1[20];
+
+ if (!istate->initialized)
+ return 0;
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return 0;
+
+ if (fstat(fd, &st))
+ goto out;
+
+ if (st.st_size < sizeof(struct cache_header) + 20)
+ goto out;
+
+ n = pread_in_full(fd, sha1, 20, st.st_size - 20);
+ if (n != 20)
+ goto out;
+
+ if (hashcmp(istate->sha1, sha1))
+ goto out;
+
+ close(fd);
+ return 1;
+
+out:
+ close(fd);
+ return 0;
+}
+
+static int verify_index(const struct index_state *istate)
+{
+ return verify_index_from(istate, get_index_file());
+}
+
static int has_racy_timestamp(struct index_state *istate)
{
int entries = istate->cache_nr;
@@ -1779,7 +1824,7 @@ static int has_racy_timestamp(struct index_state *istate)
void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
{
if ((istate->cache_changed || has_racy_timestamp(istate)) &&
- !write_index(istate, lockfile->fd))
+ verify_index(istate) && !write_index(istate, lockfile->fd))
commit_locked_index(lockfile);
else
rollback_lock_file(lockfile);
diff --git a/wrapper.c b/wrapper.c
index 0cc56368bd..bc1bfb8600 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -174,6 +174,24 @@ ssize_t xwrite(int fd, const void *buf, size_t len)
}
}
+/*
+ * xpread() is the same as pread(), but it automatically restarts pread()
+ * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
+ * NOT GUARANTEE that "len" bytes is read even if the data is available.
+ */
+ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
+{
+ ssize_t nr;
+ if (len > MAX_IO_SIZE)
+ len = MAX_IO_SIZE;
+ while (1) {
+ nr = pread(fd, buf, len, offset);
+ if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
+ continue;
+ return nr;
+ }
+}
+
ssize_t read_in_full(int fd, void *buf, size_t count)
{
char *p = buf;
@@ -214,6 +232,26 @@ ssize_t write_in_full(int fd, const void *buf, size_t count)
return total;
}
+ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
+{
+ char *p = buf;
+ ssize_t total = 0;
+
+ while (count > 0) {
+ ssize_t loaded = xpread(fd, p, count, offset);
+ if (loaded < 0)
+ return -1;
+ if (loaded == 0)
+ return total;
+ count -= loaded;
+ p += loaded;
+ total += loaded;
+ offset += loaded;
+ }
+
+ return total;
+}
+
int xdup(int fd)
{
int ret = dup(fd);