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[PATCH v6 30/39] resolve_symlink(): use a strbuf for internal scratch space

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Sep 26, 2014, 10:08 UTC
Message-ID
<1411726119-31598-31-git-send-email-mhagger@alum.mit.edu>
In-Reply-To
<1411726119-31598-1-git-send-email-mhagger@alum.mit.edu>

Aside from shortening and simplifying the code, this removes another place where the path name length is arbitrarily limited.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 lockfile.c | 33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)
diff --git a/lockfile.c b/lockfile.c
index 85c8648..cc9b9cb 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -126,44 +126,35 @@ static char *last_path_elm(char *p)
 static char *resolve_symlink(char *p, size_t s)
 {
 	int depth = MAXDEPTH;
+	static struct strbuf link = STRBUF_INIT;
 
 	while (depth--) {
-		char link[PATH_MAX];
-		int link_len = readlink(p, link, sizeof(link));
-		if (link_len < 0) {
-			/* not a symlink anymore */
-			return p;
-		}
-		else if (link_len < sizeof(link))
-			/* readlink() never null-terminates */
-			link[link_len] = '\0';
-		else {
-			warning("%s: symlink too long", p);
-			return p;
-		}
+		if (strbuf_readlink(&link, p, strlen(p)) < 0)
+			break;
 
-		if (is_absolute_path(link)) {
+		if (is_absolute_path(link.buf)) {
 			/* absolute path simply replaces p */
-			if (link_len < s)
-				strcpy(p, link);
+			if (link.len < s)
+				strcpy(p, link.buf);
 			else {
 				warning("%s: symlink too long", p);
-				return p;
+				break;
 			}
 		} else {
 			/*
-			 * link is a relative path, so I must replace the
+			 * link is a relative path, so replace the
 			 * last element of p with it.
 			 */
 			char *r = (char *)last_path_elm(p);
-			if (r - p + link_len < s)
-				strcpy(r, link);
+			if (r - p + link.len < s)
+				strcpy(r, link.buf);
 			else {
 				warning("%s: symlink too long", p);
-				return p;
+				break;
 			}
 		}
 	}
+	strbuf_reset(&link);
 	return p;
 }
 
-- 
2.1.0
Previous: Michael HaggertyNext: Michael Haggerty
Message 43 of 55 in “Lockfile correctness and refactoring”
  1. 00/39 Lockfile correctness and refactoringMichael Haggerty, Sep 26, 2014
  2. 01/39 unable_to_lock_die(): rename function from unable_to_lock_index_die()Michael Haggerty, Sep 26, 2014
  3. 02/39 api-lockfile: revise and expand the documentationMichael Haggerty, Sep 26, 2014
  4. Junio C HamanoSep 26, 2014
  5. Michael HaggertySep 30, 2014
  6. Junio C HamanoSep 30, 2014
  7. Michael HaggertyOct 1, 2014
  8. Junio C HamanoSep 26, 2014
  9. Michael HaggertySep 30, 2014
  10. Jeff KingSep 30, 2014
  11. Junio C HamanoSep 30, 2014
  12. Michael HaggertyOct 1, 2014
  13. 03/39 close_lock_file(): exit (successfully) if file is already closedMichael Haggerty, Sep 26, 2014
  14. 04/39 rollback_lock_file(): do not clear filename redundantlyMichael Haggerty, Sep 26, 2014
  15. 05/39 rollback_lock_file(): exit early if lock is not activeMichael Haggerty, Sep 26, 2014
  16. 06/39 rollback_lock_file(): set fd to -1Michael Haggerty, Sep 26, 2014
  17. 07/39 lockfile: unlock file if lockfile permissions cannot be adjustedMichael Haggerty, Sep 26, 2014
  18. 08/39 hold_lock_file_for_append(): release lock on errorsMichael Haggerty, Sep 26, 2014
  19. 09/39 lock_file(): always initialize and register lock_file objectMichael Haggerty, Sep 26, 2014
  20. 10/39 lockfile.c: document the various states of lock_file objectsMichael Haggerty, Sep 26, 2014
  21. 11/39 cache.h: define constants LOCK_SUFFIX and LOCK_SUFFIX_LENMichael Haggerty, Sep 26, 2014
  22. 12/39 delete_ref_loose(): don't muck around in the lock_file's filenameMichael Haggerty, Sep 26, 2014
  23. 13/39 prepare_index(): declare return value to be (const char *)Michael Haggerty, Sep 26, 2014
  24. 14/39 write_packed_entry_fn(): convert cb_data into a (const int *)Michael Haggerty, Sep 26, 2014
  25. 15/39 lock_file(): exit early if lockfile cannot be openedMichael Haggerty, Sep 26, 2014
  26. 16/39 remove_lock_file(): call rollback_lock_file()Michael Haggerty, Sep 26, 2014
  27. 17/39 commit_lock_file(): inline temporary variableMichael Haggerty, Sep 26, 2014
  28. 18/39 commit_lock_file(): die() if called for unlocked lockfile objectMichael Haggerty, Sep 26, 2014
  29. 19/39 close_lock_file(): if close fails, roll backMichael Haggerty, Sep 26, 2014
  30. 20/39 commit_lock_file(): rollback lock file on failure to renameMichael Haggerty, Sep 26, 2014
  31. 21/39 api-lockfile: document edge casesMichael Haggerty, Sep 26, 2014
  32. 22/39 dump_marks(): remove a redundant call to rollback_lock_file()Michael Haggerty, Sep 26, 2014
  33. 23/39 git_config_set_multivar_in_file(): avoid call to rollback_lock_file()Michael Haggerty, Sep 26, 2014
  34. 24/39 lockfile: avoid transitory invalid statesMichael Haggerty, Sep 26, 2014
  35. 25/39 struct lock_file: declare some fields volatileMichael Haggerty, Sep 26, 2014
  36. 26/39 try_merge_strategy(): remove redundant lock_file allocationMichael Haggerty, Sep 26, 2014
  37. 27/39 try_merge_strategy(): use a statically-allocated lock_file objectMichael Haggerty, Sep 26, 2014
  38. Junio C HamanoSep 26, 2014
  39. Michael HaggertySep 30, 2014
  40. Junio C HamanoSep 30, 2014
  41. 28/39 commit_lock_file(): use a strbuf to manage temporary spaceMichael Haggerty, Sep 26, 2014
  42. 29/39 Change lock_file::filename into a strbufMichael Haggerty, Sep 26, 2014
  43. 30/39 resolve_symlink(): use a strbuf for internal scratch spaceMichael Haggerty, Sep 26, 2014
  44. 31/39 resolve_symlink(): take a strbuf parameterMichael Haggerty, Sep 26, 2014
  45. 32/39 trim_last_path_component(): replace last_path_elm()Michael Haggerty, Sep 26, 2014
  46. 33/39 Extract a function commit_lock_file_to()Michael Haggerty, Sep 26, 2014
  47. 34/39 Rename LOCK_NODEREF to LOCK_NO_DEREFMichael Haggerty, Sep 26, 2014
  48. 35/39 lockfile.c: rename static functionsMichael Haggerty, Sep 26, 2014
  49. 36/39 get_locked_file_path(): new functionMichael Haggerty, Sep 26, 2014
  50. 37/39 hold_lock_file_for_append(): restore errno before returningMichael Haggerty, Sep 26, 2014
  51. 38/39 Move read_index() definition to read-cache.cMichael Haggerty, Sep 26, 2014
  52. 39/39 lockfile.h: extract new header file for the functions in lockfile.cMichael Haggerty, Sep 26, 2014
  53. Junio C HamanoSep 26, 2014
  54. Michael HaggertySep 30, 2014
  55. Junio C HamanoSep 26, 2014

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