Changeset 3710

Timestamp:

Mar 17, 2011, 5:22:45 PM (14 years ago)

Author:

bird

Message:

_getdcwd: When the buffer is NULL, the size is just a minimum. Refernces #194.

File:

• trunk/libc/src/libc/misc/_getdcwd.c (modified) (3 diffs)

trunk/libc/src/libc/misc/_getdcwd.c

@@ -50 +50 @@
  * @param   pszBuffer   Where to store the current directory of the drive.
  *                      If NULL a buffer will be malloc'ed. The size of the malloc'ed
- *                      buffer will be cchBuffer and if cchBuffer is 0 it will be
- *                      as big as necessary.
- * @param   cchBuffer   Size of the buffer.
+ *                      buffer will be at least @a cbBuffer bytes.
+ * @param   cbBuffer    The size of the buffer @a pszBuffer points to.  If 
+                        @a pszbuffer is NULL, it specifies the minimum buffer 
+                        size of the allocated buffer.
  */
-char *_getdcwd(int iDrive, char *pszBuffer, int cchBuffer)
+char *_getdcwd(int iDrive, char *pszBuffer, int cbBuffer)
 {
-    LIBCLOG_ENTER("iDrive=%d pszBuffer=%p cchBuffer=%d\n", iDrive, (void *)pszBuffer, cchBuffer);
+    LIBCLOG_ENTER("iDrive=%d pszBuffer=%p cbBuffer=%d\n", iDrive, (void *)pszBuffer, cbBuffer);
     char chDrive = iDrive ? iDrive + 'A' - 1 : 0;
 
@@ -62 +63 @@
     if (!pszBuffer)
     {
-        LIBCLOG_MSG("Allocating buffer, %d bytes.\n", cchBuffer ? cchBuffer : PATH_MAX);
-        size_t cch = cchBuffer ? cchBuffer : PATH_MAX;
-        pszBuffer = malloc(cch);
+        size_t cbAlloced = cbBuffer > PATH_MAX ? cbBuffer : PATH_MAX + 1;
+        LIBCLOG_MSG("Allocating buffer, %zd bytes.\n", cbAlloced);
+        pszBuffer = malloc(cbAlloced);
         if (pszBuffer)
         {
-            rc = __libc_Back_fsDirCurrentGet(pszBuffer, cchBuffer, chDrive, 0);
+            rc = __libc_Back_fsDirCurrentGet(pszBuffer, cbAlloced, chDrive, 0);
             if (!rc)
             {
                 /*
-                 * Reallocate a PATH_MAX buffer before we return.
+                 * Reallocate the buffer before we return?
                  */
-                if (!cchBuffer)
+                size_t cbReturned = strlen(pszBuffer) + 1;
+                if (   cbReturned + 64 <= cbAlloced 
+                    && cbBuffer        <  (ssize_t)cbAlloced)
                 {
                     char *pvOld = pszBuffer;
-                    cch = strlen(pszBuffer) + 1;
-                    pszBuffer = realloc(pszBuffer, cch > cchBuffer ? cch : cchBuffer);
-                    if (!pszBuffer)
+                    if (cbReturned <= cbBuffer)
+                        cbReturned = cbBuffer + 1;
+                    pszBuffer = realloc(pszBuffer, cbReturned);
+                    if (pszBuffer)
+                        cbAlloced = cbReturned;
+                    else
                         pszBuffer = pvOld;
                 }
-                LIBCLOG_RETURN_MSG(pszBuffer, "ret %p:{%s}\n", (void *)pszBuffer, pszBuffer);
+                LIBCLOG_RETURN_MSG(pszBuffer, "ret %p:{%s} (%zu bytes)\n", (void *)pszBuffer, pszBuffer, cbAlloced);
             }
+
             free(pszBuffer);
         }
@@ -90 +97 @@
     else
     {
-        rc = __libc_Back_fsDirCurrentGet(pszBuffer, cchBuffer, chDrive, 0);
+        rc = __libc_Back_fsDirCurrentGet(pszBuffer, cbBuffer, chDrive, 0);
         if (!rc)
             LIBCLOG_RETURN_MSG(pszBuffer, "ret %p:{%s}\n", (void *)pszBuffer, pszBuffer);