1 files changed, 52 insertions, 5 deletions

diff --git a/src/output.c b/src/output.c
index 3cf68af..4c660d6 100644
--- a/src/output.c
+++ b/src/output.c
@@ -51,6 +51,7 @@ void out_print_user_name(struct list_node *ptr);
 
 void out_print_format_string_header(const char *format, size_t longest_fname);
 
+size_t estimate_formatted_line_length(const char *format, size_t longest_fname);
 size_t get_longest_filename(struct list_head *list);
 
 
@@ -314,18 +315,62 @@ inline void out_print_permissions(struct list_node *ptr) {
     printf(" %4o ", mode);
 }
 
+/* Interpret the format string and based on it generate a size which will be
+ * able to store everything including visual additions. Use strlen later.  */
+inline size_t estimate_formatted_line_length(const char *format, size_t longest_fname) {
+    size_t rc = 0, i=0, format_len=0;
+    static int login_name_max = -1;
+    if (login_name_max < 0) {
+        /* TODO: Check whether all UNIX likes use this for user and group name*/
+        if ((login_name_max=(int)sysconf(_SC_LOGIN_NAME_MAX)) < 0) {
+            LOGERR("ERROR: sysconf(_SC_LOGIN_NAME_MAX) failed: %s (errno %d)\n",
+                strerror(errno), errno);
+            return 0;
+        }
+        DBGTRC("DEBUG: sysconf(_SC_LOGIN_NAME_MAX) = %d\n", login_name_max);
+        login_name_max += 4; /* formatting additions */
+    }
+    format_len = strnlen(format, DM_OUT_FORMAT_MAX_LEN);
+    for (i=0; i<format_len; i++) {
+        switch (format[i]) {
+            case 'n': rc += longest_fname+4; break;
+            case 'G':
+            case 'U': rc += ((unsigned int)login_name_max); break;
+            case 'g': /* Short ones */
+            case 'p':
+            case 'u': rc += 8; break;
+            case ' ': break;
+            default: rc += 28; /* time, and strings >10 in format*/
+        };
+    }
+    DBGTRC("DEBUG: format string '%s' estimated with %lu bytes\n", format, rc);
+    return rc;
+}
+
 inline void out_print_format_string_header(const char *format, size_t longest_fname) {
-    size_t i=0, j=0, k=0, format_len=0, tmp = 0;
-    char header[4096] = "", sep_line[4096] = "";
-    char *pos = header;
+    size_t i=0, j=0, k=0, format_len=0, est_length=0, tmp = 0;
+    char *header = NULL, *sep_line = NULL;
+    char *pos = NULL;
 
-    if (format == NULL || longest_fname == 0) return;
+    if (format == NULL || format[0] == '\0' || longest_fname == 0) return;
     DBGTRC("DEBUG: format string: \"%s\"\n", format);
 
-
     format_len = strnlen(format, DM_OUT_FORMAT_MAX_LEN);
 
+    est_length = estimate_formatted_line_length(format, longest_fname);
+    if ((header=calloc(est_length, sizeof(char))) == NULL) {
+        LOGERR("ERROR: Failed to allocate memory for header\n");
+        return;
+    }
+
+    pos = header;
+
     if (option_print_boxed_table) {
+        if ((sep_line=calloc(est_length, sizeof(char))) == NULL) {
+            free(header);
+            LOGERR("ERROR: Failed to allocate memory for sep line\n");
+            return;
+        }
         if (global_sep_line != NULL) { free(global_sep_line); }
         pos[0] = box_vsep;
         pos++;
@@ -429,11 +474,13 @@ inline void out_print_format_string_header(const char *format, size_t longest_fn
         fputs(sep_line, stdout);
         if ((global_sep_line = calloc(tmp+1, sizeof(char))) != NULL) {
             memcpy(global_sep_line, sep_line, tmp);
+            free(sep_line);
         }
     } else {
         fputc_width_x('-', strlen(header), stdout);
     }
     out_print_newline();
+    free(header);
 #undef LOCAL_EXTEND_SEP_LINE
 }
 /* === END OF FORMATTING FUNCTIONS === */