Use sigaction and SA_RESTART in read-tree.c; add option in Makefile.

Might as well ape the sigaction change in read-tree.c to avoid
the same potential problems.  The fprintf status output will
be overwritten in a second, so don't bother guarding it.  Do
move the fputc after disabling SIGALRM to ensure we go to the
next line, though.

Also add a NO_SA_RESTART option in the Makefile in case someone
doesn't have SA_RESTART but does restart (maybe older HP/UX?).
We want the builder to chose this specifically in case the
system both lacks SA_RESTART and does not restart stdio calls;
a compat #define in git-compat-utils.h would silently allow
broken systems.

Signed-off-by: Jason Riedy <ejr@cs.berkeley.edu>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/read-tree.c b/read-tree.c
index da0fcf0..32fb6fa 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -273,10 +273,26 @@ static void unlink_entry(char *name)
 
 static void progress_interval(int signum)
 {
-       signal(SIGALRM, progress_interval);
        progress_update = 1;
 }
 
+static void setup_progress_signal(void)
+{
+       struct sigaction sa;
+       struct itimerval v;
+
+       memset(&sa, 0, sizeof(sa));
+       sa.sa_handler = progress_interval;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       sigaction(SIGALRM, &sa, NULL);
+
+       v.it_interval.tv_sec = 1;
+       v.it_interval.tv_usec = 0;
+       v.it_value = v.it_interval;
+       setitimer(ITIMER_REAL, &v, NULL);
+}
+
 static void check_updates(struct cache_entry **src, int nr)
 {
        static struct checkout state = {
@@ -289,8 +305,6 @@ static void check_updates(struct cache_entry **src, int nr)
        unsigned last_percent = 200, cnt = 0, total = 0;
 
        if (update && verbose_update) {
-               struct itimerval v;
-
                for (total = cnt = 0; cnt < nr; cnt++) {
                        struct cache_entry *ce = src[cnt];
                        if (!ce->ce_mode || ce->ce_flags & mask)
@@ -302,12 +316,8 @@ static void check_updates(struct cache_entry **src, int nr)
                        total = 0;
 
                if (total) {
-                       v.it_interval.tv_sec = 1;
-                       v.it_interval.tv_usec = 0;
-                       v.it_value = v.it_interval;
-                       signal(SIGALRM, progress_interval);
-                       setitimer(ITIMER_REAL, &v, NULL);
                        fprintf(stderr, "Checking files out...\n");
+                       setup_progress_signal();
                        progress_update = 1;
                }
                cnt = 0;
@@ -341,8 +351,8 @@ static void check_updates(struct cache_entry **src, int nr)
                }
        }
        if (total) {
-               fputc('\n', stderr);
                signal(SIGALRM, SIG_IGN);
+               fputc('\n', stderr);
        }
 }