Imported Upstream version 4.3.10-dfsgupstream/4.3.10-dfsgupstream

1 files changed, 80 insertions, 84 deletions

diff --git a/src/VBox/Runtime/r3/linux/sysfs.cpp b/src/VBox/Runtime/r3/linux/sysfs.cpp
index f5dfc6a57..15309330f 100644
--- a/src/VBox/Runtime/r3/linux/sysfs.cpp
+++ b/src/VBox/Runtime/r3/linux/sysfs.cpp
@@ -53,8 +53,7 @@
  * Constructs the path of a sysfs file from the format parameters passed,
  * prepending a prefix if the path is relative.
  *
- * @returns The number of characters returned, or -1 and errno set to ERANGE on
- *          failure.
+ * @returns The number of characters returned, or an iprt error code on failure.
  *
  * @param   pszPrefix  The prefix to prepend if the path is relative.  Must end
  *                     in '/'.
@@ -70,8 +69,8 @@ static ssize_t rtLinuxConstructPathV(char *pszBuf, size_t cchBuf,
                                      const char *pszFormat, va_list va)
 {
     size_t cchPrefix = strlen(pszPrefix);
-    AssertReturnStmt(pszPrefix[cchPrefix - 1] == '/', errno = ERANGE, -1);
-    AssertReturnStmt(cchBuf > cchPrefix + 1, errno = ERANGE, -1);
+    AssertReturn(pszPrefix[cchPrefix - 1] == '/', VERR_INVALID_PARAMETER);
+    AssertReturn(cchBuf > cchPrefix + 1, VERR_INVALID_PARAMETER);
 
     /** @todo While RTStrPrintfV prevents overflows, it doesn't make it easy to
      *        check for truncations. RTPath should provide some formatters and
@@ -80,7 +79,7 @@ static ssize_t rtLinuxConstructPathV(char *pszBuf, size_t cchBuf,
     size_t cch = RTStrPrintfV(pszBuf, cchBuf, pszFormat, va);
     if (*pszBuf != '/')
     {
-        AssertReturnStmt(cchBuf >= cch + cchPrefix + 1, errno = ERANGE, -1);
+        AssertReturn(cchBuf >= cch + cchPrefix + 1, VERR_BUFFER_OVERFLOW);
         memmove(pszBuf + cchPrefix, pszBuf, cch + 1);
         memcpy(pszBuf, pszPrefix, cchPrefix);
         cch += cchPrefix;
@@ -93,8 +92,8 @@ static ssize_t rtLinuxConstructPathV(char *pszBuf, size_t cchBuf,
  * Constructs the path of a sysfs file from the format parameters passed,
  * prepending a prefix if the path is relative.
  *
- * @returns The number of characters returned, or -1 and errno set to ERANGE on
- *        failure.
+ * @returns The number of characters returned, or an iprt error code on failure.
+ * @note  Unused.
  *
  * @param   pszPrefix  The prefix to prepend if the path is relative.  Must end
  *                     in '/'.
@@ -131,7 +130,11 @@ static ssize_t rtLinuxConstructPath(char *pszBuf, size_t cchBuf,
  */
 static ssize_t rtLinuxSysFsConstructPath(char *pszBuf, size_t cchBuf, const char *pszFormat, va_list va)
 {
-    return rtLinuxConstructPathV(pszBuf, cchBuf, "/sys/", pszFormat, va);
+    ssize_t rc = rtLinuxConstructPathV(pszBuf, cchBuf, "/sys/", pszFormat, va);
+    if (rc >= 0)
+        return rc;
+    errno = ERANGE;
+    return -1;
 }
 
 
@@ -409,125 +412,118 @@ RTDECL(ssize_t) RTLinuxSysFsGetLinkDest(char *pszBuf, size_t cchBuf, const char
 }
 
 
-static ssize_t rtLinuxFindDevicePathRecursive(dev_t DevNum, RTFMODE fMode, const char *pszBasePath,
-                                              char *pszBuf, size_t cchBuf)
+/** Search for a device node with the number @a DevNum and the type (character
+ * or block) @a fMode below the path @a pszPath.  @a pszPath MUST point to a
+ * buffer of size at least RTPATH_MAX which will be modified during the function
+ * execution.  On successful return it will contain the path to the device node
+ * found. */
+/** @note This function previously used a local stack buffer of size RTPATH_MAX
+ *    to construct the path passed to the next recursive call, which used up 4K
+ *    of stack space per iteration and caused a stack overflow on a path with
+ *    too many components. */
+static int rtLinuxFindDevicePathRecursive(dev_t DevNum, RTFMODE fMode,
+                                          char *pszPath)
 {
+    int rc;
+    PRTDIR  pDir;
+    size_t const cchPath = strlen(pszPath);
+
     /*
      * Check assumptions made by the code below.
      */
-    size_t const cchBasePath = strlen(pszBasePath);
-    AssertReturnStmt(cchBasePath < RTPATH_MAX - 10U, errno = ENAMETOOLONG, -1);
-
-    ssize_t rcRet;
-    PRTDIR  pDir;
-    int rc = RTDirOpen(&pDir, pszBasePath);
+    AssertReturn(cchPath < RTPATH_MAX - 10U, VERR_BUFFER_OVERFLOW);
+    rc = RTDirOpen(&pDir, pszPath);
     if (RT_SUCCESS(rc))
     {
-        char szPath[RTPATH_MAX]; /** @todo 4K per recursion - can easily be optimized away by passing it along pszBasePath
-                                           and only remember the length. */
-        memcpy(szPath, pszBasePath, cchBasePath + 1);
-
         for (;;)
         {
             RTDIRENTRYEX Entry;
-            rc = RTDirReadEx(pDir, &Entry, NULL, RTFSOBJATTRADD_UNIX, RTPATH_F_ON_LINK);
+            rc = RTDirReadEx(pDir, &Entry, NULL, RTFSOBJATTRADD_UNIX,
+                             RTPATH_F_ON_LINK);
             if (RT_FAILURE(rc))
-            {
-                errno = rc == VERR_NO_MORE_FILES
-                      ? ENOENT
-                      : rc == VERR_BUFFER_OVERFLOW
-                      ? EOVERFLOW
-                      : EIO;
-                rcRet = -1;
                 break;
-            }
             if (RTFS_IS_SYMLINK(Entry.Info.Attr.fMode))
                 continue;
-
+            pszPath[cchPath] = '\0';
+            rc = RTPathAppend(pszPath, RTPATH_MAX, Entry.szName);
+            if (RT_FAILURE(rc))
+                break;
             /* Do the matching. */
             if (   Entry.Info.Attr.u.Unix.Device == DevNum
                 && (Entry.Info.Attr.fMode & RTFS_TYPE_MASK) == fMode)
-            {
-                rcRet = rtLinuxConstructPath(pszBuf, cchBuf, pszBasePath, "%s", Entry.szName);
                 break;
-            }
-
             /* Recurse into subdirectories. */
             if (!RTFS_IS_DIRECTORY(Entry.Info.Attr.fMode))
                 continue;
             if (Entry.szName[0] == '.')
                 continue;
-
-            szPath[cchBasePath] = '\0';
-            rc = RTPathAppend(szPath, sizeof(szPath) - 1, Entry.szName); /* -1: for slash */
-            if (RT_FAILURE(rc))
-            {
-                errno = ENAMETOOLONG;
-                rcRet = -1;
-                break;
-            }
-            strcat(&szPath[cchBasePath], "/");
-            rcRet = rtLinuxFindDevicePathRecursive(DevNum, fMode, szPath, pszBuf, cchBuf);
-            if (rcRet >= 0 || errno != ENOENT)
+            rc = rtLinuxFindDevicePathRecursive(DevNum, fMode, pszPath);
+            if (RT_SUCCESS(rc) || rc != VERR_NO_MORE_FILES)
                 break;
         }
         RTDirClose(pDir);
     }
-    else
-    {
-        rcRet = -1;
-        errno = RTErrConvertToErrno(rc);
-    }
-    return rcRet;
+    return rc;
 }
 
 
-RTDECL(ssize_t) RTLinuxFindDevicePathV(dev_t DevNum, RTFMODE fMode, char *pszBuf, size_t cchBuf,
-                                       const char *pszSuggestion, va_list va)
+RTDECL(ssize_t) RTLinuxFindDevicePathV(dev_t DevNum, RTFMODE fMode, char *pszBuf,
+                                       size_t cchBuf, const char *pszSuggestion,
+                                       va_list va)
 {
-    AssertReturnStmt(cchBuf >= 2, errno = EINVAL, -1);
-    AssertReturnStmt(   fMode == RTFS_TYPE_DEV_CHAR
-                     || fMode == RTFS_TYPE_DEV_BLOCK,
-                     errno = EINVAL, -1);
+    char szFilename[RTPATH_MAX];
+    int rc = VINF_TRY_AGAIN;
 
+    AssertReturn(cchBuf >= 2, VERR_INVALID_PARAMETER);
+    AssertReturn(   fMode == RTFS_TYPE_DEV_CHAR
+                 || fMode == RTFS_TYPE_DEV_BLOCK,
+                 VERR_INVALID_PARAMETER);
     if (pszSuggestion)
     {
         /*
          * Construct the filename and read the link.
          */
-        char szFilename[RTPATH_MAX];
-        int rc = rtLinuxConstructPathV(szFilename, sizeof(szFilename), "/dev/", pszSuggestion, va);
-        if (rc == -1)
-            return -1;
-
-        /*
-         * Check whether the caller's suggestion was right.
-         */
-        RTFSOBJINFO Info;
-        rc = RTPathQueryInfo(szFilename, &Info, RTFSOBJATTRADD_UNIX);
-        if (   RT_SUCCESS(rc)
-            && Info.Attr.u.Unix.Device == DevNum
-            && (Info.Attr.fMode & RTFS_TYPE_MASK) == fMode)
+        rc = rtLinuxConstructPathV(szFilename, sizeof(szFilename), "/dev/",
+                                   pszSuggestion, va);
+        if (rc > 0)
         {
-            size_t cchPath = strlen(szFilename);
-            if (cchPath >= cchBuf)
-            {
-                errno = EOVERFLOW;
-                return -1;
-            }
-            memcpy(pszBuf, szFilename, cchPath + 1);
-            return cchPath;
+            /*
+             * Check whether the caller's suggestion was right.
+             */
+            RTFSOBJINFO Info;
+            rc = RTPathQueryInfo(szFilename, &Info, RTFSOBJATTRADD_UNIX);
+            if (   rc == VERR_PATH_NOT_FOUND 
+                || rc == VERR_FILE_NOT_FOUND
+                || (   RT_SUCCESS(rc)
+                    && (   Info.Attr.u.Unix.Device != DevNum
+                        || (Info.Attr.fMode & RTFS_TYPE_MASK) != fMode)))
+            /* The suggestion was wrong, fall back on the brute force attack. */
+                rc = VINF_TRY_AGAIN;
         }
-
-        /* The suggestion was wrong, fall back on the brute force attack. */
     }
 
-    return rtLinuxFindDevicePathRecursive(DevNum, fMode, "/dev/", pszBuf, cchBuf);
+    if (rc == VINF_TRY_AGAIN)
+    {
+        RTStrCopy(szFilename, sizeof(szFilename), "/dev/");
+        rc = rtLinuxFindDevicePathRecursive(DevNum, fMode, szFilename);
+    }
+    if (RT_SUCCESS(rc))
+    {
+        size_t cchPath = strlen(szFilename);
+        if (cchPath >= cchBuf)
+            return VERR_BUFFER_OVERFLOW;
+        memcpy(pszBuf, szFilename, cchPath + 1);
+        return cchPath;
+    }
+    return rc;
 }
 
 
-RTDECL(ssize_t) RTLinuxFindDevicePath(dev_t DevNum, RTFMODE fMode, char *pszBuf, size_t cchBuf,
-                                      const char *pszSuggestion, ...)
+/** @todo Do we really need to return the string length?  If the caller is
+ * interested (the current ones aren't) they can check themselves. */
+RTDECL(ssize_t) RTLinuxFindDevicePath(dev_t DevNum, RTFMODE fMode, char *pszBuf,
+                                      size_t cchBuf, const char *pszSuggestion,
+                                      ...)
 {
     va_list va;
     va_start(va, pszSuggestion);