From fd6f688120e4f18decee6a49120837f27df53b35 Mon Sep 17 00:00:00 2001
From: Alexey Sheplyakov <asheplyakov@altlinux.org>
Date: Mon, 30 Aug 2021 14:54:50 +0400
Subject: backoff.c: added dcc_backof_is_enabled() helper function

---
 src/backoff.c | 33 +++++++++++++++++----------------
 src/distcc.h  |  1 +
 2 files changed, 18 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/backoff.c b/src/backoff.c
index b3d656c..5aaf45a 100644
--- a/src/backoff.c
+++ b/src/backoff.c
@@ -52,6 +52,19 @@
 
 static int dcc_backoff_period = 60; /* seconds */
 
+static int dcc_get_backoff_period(void)
+{
+    char *bp;
+    bp = getenv("DISTCC_BACKOFF_PERIOD");
+    if (bp)
+        dcc_backoff_period = atoi(bp);
+    return dcc_backoff_period;
+}
+
+int dcc_backoff_is_enabled(void)
+{
+    return dcc_get_backoff_period() != 0;
+}
 
 /**
  * Remember that this host is working OK.
@@ -61,23 +74,17 @@ static int dcc_backoff_period = 60; /* seconds */
  **/
 int dcc_enjoyed_host(const struct dcc_hostdef *host)
 {
-    char *bp;
-
     /* special-case: if DISTCC_BACKOFF_PERIOD==0, don't manage backoff files */
-    bp = getenv("DISTCC_BACKOFF_PERIOD");
-    if (bp && (atoi(bp) == 0))
-	return 0;
+    if (!dcc_backoff_is_enabled())
+        return 0;
 
     return dcc_remove_timefile("backoff", host);
 }
 
 int dcc_disliked_host(const struct dcc_hostdef *host)
 {
-    char *bp;
-
     /* special-case: if DISTCC_BACKOFF_PERIOD==0, don't manage backoff files */
-    bp = getenv("DISTCC_BACKOFF_PERIOD");
-    if (bp && (atoi(bp) == 0))
+    if (!dcc_backoff_is_enabled())
 	return 0;
 
     /* i hate you (but only for dcc_backoff_period seconds) */
@@ -108,14 +115,8 @@ static int dcc_check_backoff(struct dcc_hostdef *host)
 int dcc_remove_disliked(struct dcc_hostdef **hostlist)
 {
     struct dcc_hostdef *h;
-    char *bp;
 
-    bp = getenv("DISTCC_BACKOFF_PERIOD");
-    if (bp)
-	dcc_backoff_period = atoi(bp);
-
-    /* special-case: if DISTCC_BACKOFF_PERIOD==0, don't manage backoff files */
-    if (dcc_backoff_period == 0)
+    if (!dcc_backoff_is_enabled())
 	return 0;
 
     while ((h = *hostlist) != NULL) {
diff --git a/src/distcc.h b/src/distcc.h
index 7860a2c..a4bfe26 100644
--- a/src/distcc.h
+++ b/src/distcc.h
@@ -190,6 +190,7 @@ int dcc_support_masquerade(char *argv[], char *progname, int *);
 int dcc_enjoyed_host(const struct dcc_hostdef *host);
 int dcc_disliked_host(const struct dcc_hostdef *host);
 int dcc_remove_disliked(struct dcc_hostdef **hostlist);
+int dcc_backoff_is_enabled(void);
 
 
 
-- 
cgit v1.2.1


From a59c8a58caa912e85867749cbd03861f4654acc1 Mon Sep 17 00:00:00 2001
From: Alexey Sheplyakov <asheplyakov@altlinux.org>
Date: Mon, 30 Aug 2021 13:58:38 +0400
Subject: Restrict the number of retries when DISTCC_BACKOFF is disabled

Since the commit a7dd5cf90e8c ("Try a new host after failing to
connect instead of immediately falling back to localhost") distcc
tries to choose a different host on connection/protocol errors.
However when backoff is disabled (DISTCC_BACKOFF_PERIOD=0)
distcc keeps retrying forever.

To avoid the problem limit the number of retries (currently to 3)
when backoff is disabled.

Closes: #434
---
 src/compile.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/compile.c b/src/compile.c
index 26d7d18..1fdee42 100644
--- a/src/compile.c
+++ b/src/compile.c
@@ -631,6 +631,18 @@ static int dcc_gcc_rewrite_fqn(char **argv)
     return -ENOENT;
 }
 
+static int dcc_get_max_retries(void)
+{
+    if (dcc_backoff_is_enabled()) {
+        /* eventually distcc will either find a suitable host or mark
+	 * all hosts as faulty (and fallback to a local compilation)
+	 */
+	return 0; /* no limit */
+    } else {
+	return 3; /* somewhat arbitrary */
+    }
+}
+
 /**
  * Execute the commands in argv remotely or locally as appropriate.
  *
@@ -687,10 +699,13 @@ dcc_build_somewhere(char *argv[],
     int cpu_lock_fd = -1, local_cpu_lock_fd = -1;
     int ret;
     int remote_ret = 0;
+    int retry_count = 0, max_retries;
     struct dcc_hostdef *host = NULL;
     char *discrepancy_filename = NULL;
     char **new_argv;
 
+    max_retries = dcc_get_max_retries();
+
     if ((ret = dcc_expand_preprocessor_options(&argv)) != 0)
         goto clean_up;
 
@@ -841,7 +856,14 @@ dcc_build_somewhere(char *argv[],
         /* dcc_compile_remote() already unlocked local_cpu_lock_fd. */
         local_cpu_lock_fd = -1;
         bad_host(host, &cpu_lock_fd, &local_cpu_lock_fd);
-        goto choose_host;
+        retry_count++;
+        if (max_retries == 0 || retry_count < max_retries)
+            goto choose_host;
+        else {
+            rs_log_warning("Couldn't find a host in %d attempts, retrying locally",
+                           retry_count);
+            goto fallback;
+	}
     }
     /* dcc_compile_remote() already unlocked local_cpu_lock_fd. */
     local_cpu_lock_fd = -1;
-- 
cgit v1.2.1