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[PATCH 3/5] safe_create_leading_directories(): add "slash" pointer

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
Dec 22, 2013, 07:14 UTC
Message-ID
<1387696451-32224-4-git-send-email-mhagger@alum.mit.edu>
In-Reply-To
<1387696451-32224-1-git-send-email-mhagger@alum.mit.edu>

Keep track of the position of the slash character separately, and restore the slash character at a single place, at the end of the while loop. This makes the next change easier to implement.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 sha1_file.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/sha1_file.c b/sha1_file.c
index cc9957e..dcfd35a 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -107,40 +107,40 @@ int mkdir_in_gitdir(const char *path)
 
 int safe_create_leading_directories(char *path)
 {
-	char *pos = path + offset_1st_component(path);
+	char *next_component = path + offset_1st_component(path);
+	int retval = 0;
 
-	while (pos) {
+	while (!retval && next_component) {
 		struct stat st;
+		char *slash = strchr(next_component, '/');
 
-		pos = strchr(pos, '/');
-		if (!pos)
-			break;
-		while (*++pos == '/')
-			;
-		if (!*pos)
-			break;
-		*--pos = '\0';
+		if (!slash)
+			return 0;
+		while (*(slash + 1) == '/')
+			slash++;
+		next_component = slash + 1;
+		if (!*next_component)
+			return 0;
+
+		*slash = '\0';
 		if (!stat(path, &st)) {
 			/* path exists */
 			if (!S_ISDIR(st.st_mode)) {
-				*pos = '/';
-				return -3;
+				retval = -3;
 			}
 		} else if (mkdir(path, 0777)) {
 			if (errno == EEXIST &&
 			    !stat(path, &st) && S_ISDIR(st.st_mode)) {
 				; /* somebody created it since we checked */
 			} else {
-				*pos = '/';
-				return -1;
+				retval = -1;
 			}
 		} else if (adjust_shared_perm(path)) {
-			*pos = '/';
-			return -2;
+			retval = -2;
 		}
-		*pos++ = '/';
+		*slash = '/';
 	}
-	return 0;
+	return retval;
 }
 
 int safe_create_leading_directories_const(const char *path)
-- 
1.8.5.1
Previous: Michael HaggertyNext: Jonathan Nieder
Message 7 of 15 in “Fix two mkdir/rmdir races”
  1. 0/5 Fix two mkdir/rmdir racesMichael Haggerty, Dec 22, 2013
  2. 1/5 safe_create_leading_directories(): modernize format of "if" chainingMichael Haggerty, Dec 22, 2013
  3. Jonathan NiederDec 26, 2013
  4. 2/5 safe_create_leading_directories(): reduce scope of local variableMichael Haggerty, Dec 22, 2013
  5. Jonathan NiederDec 26, 2013
  6. Michael HaggertyJan 1, 2014
  7. 3/5 safe_create_leading_directories(): add "slash" pointerMichael Haggerty, Dec 22, 2013
  8. Jonathan NiederDec 26, 2013
  9. Michael HaggertyJan 1, 2014
  10. 4/5 safe_create_leading_directories(): fix a mkdir/rmdir raceMichael Haggerty, Dec 22, 2013
  11. Ramsay JonesDec 22, 2013
  12. Jonathan NiederDec 26, 2013
  13. Michael HaggertyJan 2, 2014
  14. 5/5 rename_ref(): fix a mkdir()/rmdir() raceMichael Haggerty, Dec 22, 2013
  15. Jonathan NiederDec 26, 2013

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