ls: stop doing time() for each file in "ls -l"

ls: use fully-buffered stdout (can it be problematic
on VERY slow/hanging NFS mounts?)

1 files changed, 14 insertions, 1 deletions

diff --git a/coreutils/ls.c b/coreutils/ls.c
index ff0831dac..067e463ee 100644
--- a/coreutils/ls.c
+++ b/coreutils/ls.c
@@ -537,6 +537,12 @@ static struct dnode **list_dir(const char *path)
 }
 
 
+#if ENABLE_FEATURE_LS_TIMESTAMPS
+/* Do time() just once. Saves one syscall per file for "ls -l" */
+/* Initialized in main() */
+static time_t current_time_t;
+#endif
+
 static int list_single(struct dnode *dn)
 {
         int i, column = 0;
@@ -611,7 +617,8 @@ static int list_single(struct dnode *dn)
                         break;
                 case LIST_DATE_TIME:
                         if ((all_fmt & LIST_FULLTIME) == 0) {
-                                age = time(NULL) - ttime;
+                                /* current_time_t ~== time(NULL) */
+                                age = current_time_t - ttime;
                                 printf("%6.6s ", filetime + 4);
                                 if (age < 3600L * 24 * 365 / 2 && age > -15 * 60) {
                                         /* hh:mm if less than 6 months old */
@@ -785,6 +792,12 @@ int ls_main(int argc, char **argv)
         USE_FEATURE_AUTOWIDTH(char *terminal_width_str = NULL;)
         USE_FEATURE_LS_COLOR(char *color_opt;)
 
+        setvbuf(stdout, bb_common_bufsiz1, _IOFBF, BUFSIZ);
+
+#if ENABLE_FEATURE_LS_TIMESTAMPS
+        time(&current_time_t);
+#endif
+
         all_fmt = LIST_SHORT |
                 (ENABLE_FEATURE_LS_SORTFILES * (SORT_NAME | SORT_FORWARD));