Re: [PATCH] Prevent git-upload-pack segfault if object cannot be found
From: Junio C Hamano <hidden>
Date: 2016-06-15 22:42:20
Subsystem:
the rest · Maintainer:
Linus Torvalds
Possibly related (same subject, not in this thread)
- 2016-06-15 · Re: [PATCH] Prevent git-upload-pack segfault if object cannot be found · Andrew Vasquez <hidden>
- 2016-06-15 · Re: [PATCH] Prevent git-upload-pack segfault if object cannot be found · Junio C Hamano <hidden>
- 2016-06-15 · Re: [PATCH] Prevent git-upload-pack segfault if object cannot be found · Carl Worth <hidden>
- 2016-06-15 · Re: [PATCH] Prevent git-upload-pack segfault if object cannot be found · Junio C Hamano <hidden>
- 2016-06-15 · [PATCH] Prevent git-upload-pack segfault if object cannot be found · Carl Worth <hidden>
Carl Worth [off-list ref] writes:
In the case in which I hit the original bug, this message is necessary to provide information about where the actual problem is. Here is what that scenario looks like with the message: $ mkdir original; $ (cd original; git-init-db; touch foo; git add foo; git commit -m "original") defaulting to local storage area Committing initial tree 4d5fcadc293a348e88f777dc0920f11e7d71441c $ git clone -l -s original clone $ mv original moved $ git clone clone again unable to open object pack directory: /tmp/original/.git/objects/pack: No such file or directory fatal: git-upload-pack: cannot find object 0153d496df669cbe5cecb665dbe6f95b20461917: fatal: unexpected EOF clone-pack from '/tmp/clone/.git' failed. Here the "cannot find object" message doesn't point to the core problem, but the "unable to open object pack directory" does contain the "/tmp/original" path of interest.
Updated patch. The root cause of the problem you had was that alternates was dangling, so we catch that. -- >8 --
diff --git a/sha1_file.c b/sha1_file.c
index f08b1d6..c08da35 100644
--- a/sha1_file.c
+++ b/sha1_file.c@@ -247,6 +247,7 @@ static void link_alt_odb_entries(const c for ( ; cp < ep && *cp != sep; cp++) ; if (last != cp) { + struct stat st; struct alternate_object_database *alt; /* 43 = 40-byte + 2 '/' + terminating NUL */ int pfxlen = cp - last;
@@ -269,9 +270,19 @@ static void link_alt_odb_entries(const c } else memcpy(ent->base, last, pfxlen); + ent->name = ent->base + pfxlen + 1; - ent->base[pfxlen] = ent->base[pfxlen + 3] = '/'; - ent->base[entlen-1] = 0; + ent->base[pfxlen + 3] = '/'; + ent->base[pfxlen] = ent->base[entlen-1] = 0; + + /* Detect cases where alternate disappeared */ + if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) { + error("object directory %s does not exist; " + "check .git/objects/info/alternates.", + ent->base); + goto bad; + } + ent->base[pfxlen] = '/'; /* Prevent the common mistake of listing the same * thing twice, or object directory itself.
@@ -552,7 +563,9 @@ static void prepare_packed_git_one(char len = strlen(path); dir = opendir(path); if (!dir) { - fprintf(stderr, "unable to open object pack directory: %s: %s\n", path, strerror(errno)); + if (errno != ENOENT) + error("unable to open object pack directory: %s: %s\n", + path, strerror(errno)); return; } path[len++] = '/';