logger: realloc buffer when header size changed

This is probably paranoid optimization, but when we generate a new
header we need to be sure that buffer is not smaller than calculated
maximal size of user's data.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index 23da164cd657f4198823396ba945b07b97d85f47..4511ab11418369b9513148bfc85eb7f9c0101809 100644 (file)
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -979,11 +979,11 @@ static void logger_stdin(struct logger_ctl *ctl)
         * update header timestamps and to reflect possible priority changes.
         * The initial header is generated by logger_open().
         */
-       int has_header = 1;
        int default_priority = ctl->pri;
        int last_pri = default_priority;
        size_t max_usrmsg_size = ctl->max_message_size - strlen(ctl->hdr);
-       char *const buf = xmalloc(max_usrmsg_size + 2 + 2);
+       size_t allocated_usrmsg_size = max_usrmsg_size;
+       char *buf = xmalloc(allocated_usrmsg_size + 2 + 2);
        int pri;
        int c;
        size_t i;
@@ -1010,9 +1010,14 @@ static void logger_stdin(struct logger_ctl *ctl)
                                ctl->pri = default_priority;
 
                        if (ctl->pri != last_pri) {
-                               has_header = 0;
-                               max_usrmsg_size =
-                                   ctl->max_message_size - strlen(ctl->hdr);
+                               generate_syslog_header(ctl);
+                               max_usrmsg_size = ctl->max_message_size - strlen(ctl->hdr);
+
+                               if (max_usrmsg_size > allocated_usrmsg_size) {
+                                       allocated_usrmsg_size = max_usrmsg_size;
+                                       buf = xrealloc(buf, allocated_usrmsg_size + 2 + 2);
+                               }
+
                                last_pri = ctl->pri;
                        }
                        if (c != EOF && c != '\n')
@@ -1025,12 +1030,8 @@ static void logger_stdin(struct logger_ctl *ctl)
                }
                buf[i] = '\0';
 
-               if (i > 0 || !ctl->skip_empty_lines) {
-                       if (!has_header)
-                               generate_syslog_header(ctl);
+               if (i > 0 || !ctl->skip_empty_lines)
                        write_output(ctl, buf);
-                       has_header = 0;
-               }
 
                if (c == '\n')  /* discard line terminator */
                        c = getchar();