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[PATCH v3 04/21] die_unterminated_line(), die_invalid_line(): new functions

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Sep 25, 2017, 08:00 UTC
Message-ID
<55b1102936de66e00bdee75cd38454a70d4228af.1506325610.git.mhagger@alum.mit.edu>
In-Reply-To
<cover.1506325610.git.mhagger@alum.mit.edu>

Extract some helper functions for reporting errors. While we're at it, prevent them from spewing unlimited output to the terminal. These functions will soon have more callers.

These functions accept the problematic line as a `(ptr, len)` pair rather than a NUL-terminated string, and `die_invalid_line()` checks for an EOL itself, because these calling conventions will be convenient for future callers. (Efficiency is not a concern here because these functions are only ever called if the `packed-refs` file is corrupt.)

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs/packed-backend.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index a3d9210cb0..5c50c223ef 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -161,6 +161,29 @@ static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
 	return ref;
 }
 
+static NORETURN void die_unterminated_line(const char *path,
+					   const char *p, size_t len)
+{
+	if (len < 80)
+		die("unterminated line in %s: %.*s", path, (int)len, p);
+	else
+		die("unterminated line in %s: %.75s...", path, p);
+}
+
+static NORETURN void die_invalid_line(const char *path,
+				      const char *p, size_t len)
+{
+	const char *eol = memchr(p, '\n', len);
+
+	if (!eol)
+		die_unterminated_line(path, p, len);
+	else if (eol - p < 80)
+		die("unexpected line in %s: %.*s", path, (int)(eol - p), p);
+	else
+		die("unexpected line in %s: %.75s...", path, p);
+
+}
+
 /*
  * Read from the `packed-refs` file into a newly-allocated
  * `packed_ref_cache` and return it. The return value will already
@@ -227,7 +250,7 @@ static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
 		const char *traits;
 
 		if (!line.len || line.buf[line.len - 1] != '\n')
-			die("unterminated line in %s: %s", refs->path, line.buf);
+			die_unterminated_line(refs->path, line.buf, line.len);
 
 		if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
 			if (strstr(traits, " fully-peeled "))
@@ -266,8 +289,7 @@ static struct packed_ref_cache *read_packed_refs(struct packed_ref_store *refs)
 			 */
 			last->flag |= REF_KNOWS_PEELED;
 		} else {
-			strbuf_setlen(&line, line.len - 1);
-			die("unexpected line in %s: %s", refs->path, line.buf);
+			die_invalid_line(refs->path, line.buf, line.len);
 		}
 	}
 

-- 
2.14.1
Previous: Michael HaggertyNext: Michael Haggerty
Message 5 of 24 in “Read `packed-refs` using mmap()”
  1. 00/21 Read `packed-refs` using mmap()Michael Haggerty, Sep 25, 2017
  2. 01/21 ref_iterator: keep track of whether the iterator output is orderedMichael Haggerty, Sep 25, 2017
  3. 02/21 prefix_ref_iterator: break when we leave the prefixMichael Haggerty, Sep 25, 2017
  4. 03/21 packed_ref_cache: add a backlink to the associated `packed_ref_store`Michael Haggerty, Sep 25, 2017
  5. 04/21 die_unterminated_line(), die_invalid_line(): new functionsMichael Haggerty, Sep 25, 2017
  6. 05/21 read_packed_refs(): use mmap to read the `packed-refs` fileMichael Haggerty, Sep 25, 2017
  7. 06/21 read_packed_refs(): only check for a header at the top of the fileMichael Haggerty, Sep 25, 2017
  8. 07/21 read_packed_refs(): make parsing of the header line more robustMichael Haggerty, Sep 25, 2017
  9. 09/21 packed_ref_cache: remember the file-wide peeling stateMichael Haggerty, Sep 25, 2017
  10. 08/21 read_packed_refs(): read references with minimal copyingMichael Haggerty, Sep 25, 2017
  11. 10/21 mmapped_ref_iterator: add iterator over a packed-refs fileMichael Haggerty, Sep 25, 2017
  12. 12/21 packed-backend.c: reorder some definitionsMichael Haggerty, Sep 25, 2017
  13. 13/21 packed_ref_cache: keep the `packed-refs` file mmapped if possibleMichael Haggerty, Sep 25, 2017
  14. 14/21 read_packed_refs(): ensure that references are ordered when readMichael Haggerty, Sep 25, 2017
  15. 11/21 mmapped_ref_iterator_advance(): no peeled value for broken refsMichael Haggerty, Sep 25, 2017
  16. 15/21 packed_ref_iterator_begin(): iterate using `mmapped_ref_iterator`Michael Haggerty, Sep 25, 2017
  17. 16/21 packed_read_raw_ref(): read the reference from the mmapped bufferMichael Haggerty, Sep 25, 2017
  18. 17/21 ref_store: implement `refs_peel_ref()` genericallyMichael Haggerty, Sep 25, 2017
  19. 18/21 packed_ref_store: get rid of the `ref_cache` entirelyMichael Haggerty, Sep 25, 2017
  20. 20/21 mmapped_ref_iterator: inline into `packed_ref_iterator`Michael Haggerty, Sep 25, 2017
  21. 19/21 ref_cache: remove support for storing peeled valuesMichael Haggerty, Sep 25, 2017
  22. 21/21 packed-backend.c: rename a bunch of things and update commentsMichael Haggerty, Sep 25, 2017
  23. Jeff KingSep 25, 2017
  24. Junio C HamanoSep 29, 2017

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