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Diffstat (limited to 'sha1_file.c')
-rw-r--r--sha1_file.c267
1 files changed, 244 insertions, 23 deletions
diff --git a/sha1_file.c b/sha1_file.c
index 1eb47f6113..6628f06da3 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -129,8 +129,10 @@ enum scld_error safe_create_leading_directories(char *path)
*slash = '\0';
if (!stat(path, &st)) {
/* path exists */
- if (!S_ISDIR(st.st_mode))
+ if (!S_ISDIR(st.st_mode)) {
+ errno = ENOTDIR;
ret = SCLD_EXISTS;
+ }
} else if (mkdir(path, 0777)) {
if (errno == EEXIST &&
!stat(path, &st) && S_ISDIR(st.st_mode))
@@ -158,13 +160,85 @@ enum scld_error safe_create_leading_directories(char *path)
enum scld_error safe_create_leading_directories_const(const char *path)
{
+ int save_errno;
/* path points to cache entries, so xstrdup before messing with it */
char *buf = xstrdup(path);
enum scld_error result = safe_create_leading_directories(buf);
+
+ save_errno = errno;
free(buf);
+ errno = save_errno;
return result;
}
+int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
+{
+ /*
+ * The number of times we will try to remove empty directories
+ * in the way of path. This is only 1 because if another
+ * process is racily creating directories that conflict with
+ * us, we don't want to fight against them.
+ */
+ int remove_directories_remaining = 1;
+
+ /*
+ * The number of times that we will try to create the
+ * directories containing path. We are willing to attempt this
+ * more than once, because another process could be trying to
+ * clean up empty directories at the same time as we are
+ * trying to create them.
+ */
+ int create_directories_remaining = 3;
+
+ /* A scratch copy of path, filled lazily if we need it: */
+ struct strbuf path_copy = STRBUF_INIT;
+
+ int ret, save_errno;
+
+ /* Sanity check: */
+ assert(*path);
+
+retry_fn:
+ ret = fn(path, cb);
+ save_errno = errno;
+ if (!ret)
+ goto out;
+
+ if (errno == EISDIR && remove_directories_remaining-- > 0) {
+ /*
+ * A directory is in the way. Maybe it is empty; try
+ * to remove it:
+ */
+ if (!path_copy.len)
+ strbuf_addstr(&path_copy, path);
+
+ if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
+ goto retry_fn;
+ } else if (errno == ENOENT && create_directories_remaining-- > 0) {
+ /*
+ * Maybe the containing directory didn't exist, or
+ * maybe it was just deleted by a process that is
+ * racing with us to clean up empty directories. Try
+ * to create it:
+ */
+ enum scld_error scld_result;
+
+ if (!path_copy.len)
+ strbuf_addstr(&path_copy, path);
+
+ do {
+ scld_result = safe_create_leading_directories(path_copy.buf);
+ if (scld_result == SCLD_OK)
+ goto retry_fn;
+ } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
+ }
+
+out:
+ strbuf_release(&path_copy);
+ errno = save_errno;
+ return ret;
+}
+
static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
{
int i;
@@ -284,7 +358,7 @@ static int link_alt_odb_entry(const char *entry, const char *relative_base,
struct strbuf pathbuf = STRBUF_INIT;
if (!is_absolute_path(entry) && relative_base) {
- strbuf_addstr(&pathbuf, real_path(relative_base));
+ strbuf_realpath(&pathbuf, relative_base, 1);
strbuf_addch(&pathbuf, '/');
}
strbuf_addstr(&pathbuf, entry);
@@ -1630,39 +1704,54 @@ int git_open_cloexec(const char *name, int flags)
return fd;
}
-static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
+/*
+ * Find "sha1" as a loose object in the local repository or in an alternate.
+ * Returns 0 on success, negative on failure.
+ *
+ * The "path" out-parameter will give the path of the object we found (if any).
+ * Note that it may point to static storage and is only valid until another
+ * call to sha1_file_name(), etc.
+ */
+static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
+ const char **path)
{
struct alternate_object_database *alt;
- if (!lstat(sha1_file_name(sha1), st))
+ *path = sha1_file_name(sha1);
+ if (!lstat(*path, st))
return 0;
prepare_alt_odb();
errno = ENOENT;
for (alt = alt_odb_list; alt; alt = alt->next) {
- const char *path = alt_sha1_path(alt, sha1);
- if (!lstat(path, st))
+ *path = alt_sha1_path(alt, sha1);
+ if (!lstat(*path, st))
return 0;
}
return -1;
}
-static int open_sha1_file(const unsigned char *sha1)
+/*
+ * Like stat_sha1_file(), but actually open the object and return the
+ * descriptor. See the caveats on the "path" parameter above.
+ */
+static int open_sha1_file(const unsigned char *sha1, const char **path)
{
int fd;
struct alternate_object_database *alt;
int most_interesting_errno;
- fd = git_open(sha1_file_name(sha1));
+ *path = sha1_file_name(sha1);
+ fd = git_open(*path);
if (fd >= 0)
return fd;
most_interesting_errno = errno;
prepare_alt_odb();
for (alt = alt_odb_list; alt; alt = alt->next) {
- const char *path = alt_sha1_path(alt, sha1);
- fd = git_open(path);
+ *path = alt_sha1_path(alt, sha1);
+ fd = git_open(*path);
if (fd >= 0)
return fd;
if (most_interesting_errno == ENOENT)
@@ -1672,12 +1761,21 @@ static int open_sha1_file(const unsigned char *sha1)
return -1;
}
-void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+/*
+ * Map the loose object at "path" if it is not NULL, or the path found by
+ * searching for a loose object named "sha1".
+ */
+static void *map_sha1_file_1(const char *path,
+ const unsigned char *sha1,
+ unsigned long *size)
{
void *map;
int fd;
- fd = open_sha1_file(sha1);
+ if (path)
+ fd = git_open(path);
+ else
+ fd = open_sha1_file(sha1, &path);
map = NULL;
if (fd >= 0) {
struct stat st;
@@ -1686,7 +1784,7 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
*size = xsize_t(st.st_size);
if (!*size) {
/* mmap() is forbidden on empty files */
- error("object file %s is empty", sha1_file_name(sha1));
+ error("object file %s is empty", path);
return NULL;
}
map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
@@ -1696,6 +1794,11 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
return map;
}
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+{
+ return map_sha1_file_1(NULL, sha1, size);
+}
+
unsigned long unpack_object_header_buffer(const unsigned char *buf,
unsigned long len, enum object_type *type, unsigned long *sizep)
{
@@ -2342,11 +2445,10 @@ static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
void clear_delta_base_cache(void)
{
- struct hashmap_iter iter;
- struct delta_base_cache_entry *entry;
- for (entry = hashmap_iter_first(&delta_base_cache, &iter);
- entry;
- entry = hashmap_iter_next(&iter)) {
+ struct list_head *lru, *tmp;
+ list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
+ struct delta_base_cache_entry *entry =
+ list_entry(lru, struct delta_base_cache_entry, lru);
release_delta_base_cache(entry);
}
}
@@ -2806,8 +2908,9 @@ static int sha1_loose_object_info(const unsigned char *sha1,
* object even exists.
*/
if (!oi->typep && !oi->typename && !oi->sizep) {
+ const char *path;
struct stat st;
- if (stat_sha1_file(sha1, &st) < 0)
+ if (stat_sha1_file(sha1, &st, &path) < 0)
return -1;
if (oi->disk_sizep)
*oi->disk_sizep = st.st_size;
@@ -3003,6 +3106,8 @@ void *read_sha1_file_extended(const unsigned char *sha1,
{
void *data;
const struct packed_git *p;
+ const char *path;
+ struct stat st;
const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
errno = 0;
@@ -3018,12 +3123,9 @@ void *read_sha1_file_extended(const unsigned char *sha1,
die("replacement %s not found for %s",
sha1_to_hex(repl), sha1_to_hex(sha1));
- if (has_loose_object(repl)) {
- const char *path = sha1_file_name(sha1);
-
+ if (!stat_sha1_file(repl, &st, &path))
die("loose object %s (stored in %s) is corrupt",
sha1_to_hex(repl), path);
- }
if ((p = has_packed_and_bad(repl)) != NULL)
die("packed object %s (stored in %s) is corrupt",
@@ -3793,3 +3895,122 @@ int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
}
return r ? r : pack_errors;
}
+
+static int check_stream_sha1(git_zstream *stream,
+ const char *hdr,
+ unsigned long size,
+ const char *path,
+ const unsigned char *expected_sha1)
+{
+ git_SHA_CTX c;
+ unsigned char real_sha1[GIT_SHA1_RAWSZ];
+ unsigned char buf[4096];
+ unsigned long total_read;
+ int status = Z_OK;
+
+ git_SHA1_Init(&c);
+ git_SHA1_Update(&c, hdr, stream->total_out);
+
+ /*
+ * We already read some bytes into hdr, but the ones up to the NUL
+ * do not count against the object's content size.
+ */
+ total_read = stream->total_out - strlen(hdr) - 1;
+
+ /*
+ * This size comparison must be "<=" to read the final zlib packets;
+ * see the comment in unpack_sha1_rest for details.
+ */
+ while (total_read <= size &&
+ (status == Z_OK || status == Z_BUF_ERROR)) {
+ stream->next_out = buf;
+ stream->avail_out = sizeof(buf);
+ if (size - total_read < stream->avail_out)
+ stream->avail_out = size - total_read;
+ status = git_inflate(stream, Z_FINISH);
+ git_SHA1_Update(&c, buf, stream->next_out - buf);
+ total_read += stream->next_out - buf;
+ }
+ git_inflate_end(stream);
+
+ if (status != Z_STREAM_END) {
+ error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
+ return -1;
+ }
+ if (stream->avail_in) {
+ error("garbage at end of loose object '%s'",
+ sha1_to_hex(expected_sha1));
+ return -1;
+ }
+
+ git_SHA1_Final(real_sha1, &c);
+ if (hashcmp(expected_sha1, real_sha1)) {
+ error("sha1 mismatch for %s (expected %s)", path,
+ sha1_to_hex(expected_sha1));
+ return -1;
+ }
+
+ return 0;
+}
+
+int read_loose_object(const char *path,
+ const unsigned char *expected_sha1,
+ enum object_type *type,
+ unsigned long *size,
+ void **contents)
+{
+ int ret = -1;
+ int fd = -1;
+ void *map = NULL;
+ unsigned long mapsize;
+ git_zstream stream;
+ char hdr[32];
+
+ *contents = NULL;
+
+ map = map_sha1_file_1(path, NULL, &mapsize);
+ if (!map) {
+ error_errno("unable to mmap %s", path);
+ goto out;
+ }
+
+ if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
+ error("unable to unpack header of %s", path);
+ goto out;
+ }
+
+ *type = parse_sha1_header(hdr, size);
+ if (*type < 0) {
+ error("unable to parse header of %s", path);
+ git_inflate_end(&stream);
+ goto out;
+ }
+
+ if (*type == OBJ_BLOB) {
+ if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
+ goto out;
+ } else {
+ *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
+ if (!*contents) {
+ error("unable to unpack contents of %s", path);
+ git_inflate_end(&stream);
+ goto out;
+ }
+ if (check_sha1_signature(expected_sha1, *contents,
+ *size, typename(*type))) {
+ error("sha1 mismatch for %s (expected %s)", path,
+ sha1_to_hex(expected_sha1));
+ free(*contents);
+ goto out;
+ }
+ }
+
+ ret = 0; /* everything checks out */
+
+out:
+ if (map)
+ munmap(map, mapsize);
+ if (fd >= 0)
+ close(fd);
+ return ret;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-23 02:05:15 +0000