[lxc-devel] [lxc/master] [RFC]: lxccontainer: detect if we should send SIGRTMIN+3
brauner on Github
lxc-bot at linuxcontainers.org
Mon Jul 18 20:47:47 UTC 2016
A non-text attachment was scrubbed...
Name: not available
Type: text/x-mailbox
Size: 479 bytes
Desc: not available
URL: <http://lists.linuxcontainers.org/pipermail/lxc-devel/attachments/20160718/ebb3e4a7/attachment.bin>
-------------- next part --------------
From 5defaf4373e60bc2ca0b1c1d812e3a4acceb7a26 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at mailbox.org>
Date: Mon, 18 Jul 2016 22:21:56 +0200
Subject: [PATCH] lxccontainer: detect if we should send SIGRTMIN+3
This is required by systemd to cleanly shutdown. Other init systems should not
have SIGRTMIN+3 in the blocked signals set.
Signed-off-by: Christian Brauner <cbrauner at suse.de>
---
src/lxc/lxccontainer.c | 9 +++++++++
src/lxc/utils.c | 36 ++++++++++++++++++++++++++++++++++++
src/lxc/utils.h | 5 +++++
3 files changed, 50 insertions(+)
diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 4a4dc42..7571625 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -1606,6 +1606,15 @@ static bool do_lxcapi_shutdown(struct lxc_container *c, int timeout)
return true;
if (c->lxc_conf && c->lxc_conf->haltsignal)
haltsignal = c->lxc_conf->haltsignal;
+
+ /* Detect whether we should send SIGRTMIN + 3 (e.g. systemd). */
+ if (haltsignal == SIGPWR) {
+ if (check_sigblk(pid, (SIGRTMIN + 3))) {
+ haltsignal = (SIGRTMIN + 3);
+ INFO("Using SIGRTMIN+3 as halt signal.");
+ }
+ }
+
kill(pid, haltsignal);
retv = do_lxcapi_wait(c, "STOPPED", timeout);
return retv;
diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 5c35ae8..df6988e 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -1838,3 +1838,39 @@ int lxc_strmunmap(void *addr, size_t length)
{
return munmap(addr, length + 1);
}
+
+/* Check whether we need to send SIGRTMIN+3 to init. (e.g. used by systemd to
+ * cleanly shutdown container.
+ */
+bool check_sigblk(pid_t pid, int signal)
+{
+ bool bret = false;
+ char *line = NULL;
+ long unsigned int sigblk = 0;
+ size_t n = 0;
+ char status[MAXPATHLEN];
+ int ret;
+ FILE *f;
+
+ ret = snprintf(status, MAXPATHLEN, "/proc/%d/status", pid);
+ if (ret < 0 || ret >= MAXPATHLEN)
+ return bret;
+
+ f = fopen(status, "r");
+ if (!f)
+ return bret;
+
+ while (getline(&line, &n, f) != -1) {
+ if (!strncmp(line, "SigBlk:\t", 8))
+ if (sscanf(line + 8, "%lx", &sigblk) != 1)
+ goto out;
+ }
+
+ if (sigblk & signal)
+ bret = true;
+
+out:
+ free(line);
+ fclose(f);
+ return bret;
+}
diff --git a/src/lxc/utils.h b/src/lxc/utils.h
index 22161cb..ee4d0d6 100644
--- a/src/lxc/utils.h
+++ b/src/lxc/utils.h
@@ -296,4 +296,9 @@ int open_devnull(void);
int set_stdfds(int fd);
int null_stdfds(void);
int lxc_count_file_lines(const char *fn);
+
+/* Check whether we need to send SIGRTMIN+3 to init. (e.g. used by systemd to
+ * cleanly shutdown container.
+ */
+bool check_sigblk(pid_t pid, int signal);
#endif /* __LXC_UTILS_H */
More information about the lxc-devel
mailing list