Act as the "mv" command when rotate log

Act as the "mv" command when rotate log, first rename, if failed, then
read and write.

Upstream-Status: Pending

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
---
 logrotate.c |   59 +++++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/logrotate.c b/logrotate.c
index 537e8d6..b04482f 100644
--- a/logrotate.c
+++ b/logrotate.c
@@ -808,6 +808,53 @@ int findNeedRotating(struct logInfo *log, int logNum)
     return 0;
 }
 
+/* Act as the "mv" command, if rename failed, then read the old file and
+ * write to new file. The function which invokes the mvFile will use
+ * the strerror(errorno) to handle the error message, so we don't have
+ * to print the error message here */
+
+int mvFile (char *oldName, char *newName, struct logInfo *log)
+{
+    struct stat sbprev;
+    int fd_old, fd_new, n;
+    char buf[BUFSIZ];
+
+    /* Do the rename first */
+    if (!rename(oldName, newName))
+        return 0;
+
+    /* If the errno is EXDEV, then read old file, write newfile and
+     * remove the oldfile */
+    if (errno == EXDEV) {
+        /* Open the old file to read */
+        if ((fd_old = open(oldName, O_RDONLY)) < 0)
+            return 1;
+
+        /* Create the file to write, keep the same attribute as the old file */
+        if (stat(oldName, &sbprev))
+            return 1;
+        else {
+            if ((fd_new = createOutputFile(newName,
+                O_WRONLY | O_CREAT | O_TRUNC, &sbprev)) < 0 )
+                return 1;
+        }
+
+        /* Read and write */
+        while ((n = read(fd_old, buf, BUFSIZ)) > 0)
+            if (write(fd_new, buf, n) != n)
+                return 1;
+
+        if ((close(fd_old) < 0) ||
+            removeLogFile(oldName, log) ||
+            (close(fd_new) < 0))
+            return 1;
+
+        return 0;
+    }
+
+    return 1;
+}
+
 int prerotateSingleLog(struct logInfo *log, int logNum, struct logState *state,
 		       struct logNames *rotNames)
 {
@@ -1148,15 +1195,15 @@ int prerotateSingleLog(struct logInfo *log, int logNum, struct logState *state,
 		    rotNames->baseName, i, fileext, compext);
 
 	    message(MESS_DEBUG,
-		    "renaming %s to %s (rotatecount %d, logstart %d, i %d), \n",
+		    "moving %s to %s (rotatecount %d, logstart %d, i %d), \n",
 		    oldName, newName, rotateCount, logStart, i);
 
-	    if (!debug && rename(oldName, newName)) {
+	    if (!debug && mvFile(oldName, newName, log)) {
 		if (errno == ENOENT) {
 		    message(MESS_DEBUG, "old log %s does not exist\n",
 			    oldName);
 		} else {
-		    message(MESS_ERROR, "error renaming %s to %s: %s\n",
+		    message(MESS_ERROR, "error moving %s to %s: %s\n",
 			    oldName, newName, strerror(errno));
 		    hasErrors = 1;
 		}
@@ -1286,11 +1333,11 @@ int rotateSingleLog(struct logInfo *log, int logNum, struct logState *state,
 			}
 		}
 #endif /* WITH_ACL */
-		message(MESS_DEBUG, "renaming %s to %s\n", log->files[logNum],
+        message(MESS_DEBUG, "moving %s to %s\n", log->files[logNum],
 		    rotNames->finalName);
 	    if (!debug && !hasErrors &&
-		rename(log->files[logNum], rotNames->finalName)) {
-		message(MESS_ERROR, "failed to rename %s to %s: %s\n",
+        mvFile(log->files[logNum], rotNames->finalName, log)) {
+        message(MESS_ERROR, "failed to move %s to %s: %s\n",
 			log->files[logNum], rotNames->finalName,
 			strerror(errno));
 			hasErrors = 1;
-- 
1.7.4.1