Use a lock file to prevent multiple daemons from running
simultaneously.
Without this lock, a second instance of ib_acm eventually
fails to bind to the server's TCP port and exits, but not
before it overwrites a portion of the log file.
Signed-off-by: Sean Hefty <sean.he...@intel.com>
---
acm_opts.cfg | 6 ++++++
src/acm.c | 27 +++++++++++++++++++++++++++
src/acme.c | 6 ++++++
3 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/acm_opts.cfg b/acm_opts.cfg
index 372cd7b..7147fe2 100644
--- a/acm_opts.cfg
+++ b/acm_opts.cfg
@@ -26,6 +26,12 @@ log_file /var/log/ibacm.log
log_level 0
+# lock_file:
+# Specifies the location of the ACM lock file used to ensure that only a
+# single instance of ACM is running.
+
+lock_file /var/lock/ibacm.pid
+
# addr_prot:
# Default resolution protocol to resolve IP addresses into IB GIDs.
# Supported protocols are:
diff --git a/src/acm.c b/src/acm.c
index 3152392..bc7124f 100644
--- a/src/acm.c
+++ b/src/acm.c
@@ -36,8 +36,10 @@
#include <string.h>
#include <osd.h>
#include <arpa/inet.h>
+#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
+#include <fcntl.h>
#include <infiniband/acm.h>
#include <infiniband/umad.h>
#include <infiniband/verbs.h>
@@ -208,6 +210,7 @@ static char *opts_file = "/etc/ibacm/acm_opts.cfg";
static char *addr_file = "/etc/ibacm/acm_addr.cfg";
static char log_file[128] = "stdout";
static int log_level = 0;
+static char lock_file[128] = "/var/lock/ibacm.pid";
static enum acm_addr_prot addr_prot = ACM_ADDR_PROT_ACM;
static enum acm_route_prot route_prot = ACM_ROUTE_PROT_ACM;
static enum acm_loopback_prot loopback_prot = ACM_LOOPBACK_PROT_LOCAL;
@@ -2654,6 +2657,8 @@ static void acm_set_options(void)
strcpy(log_file, value);
else if (!stricmp("log_level", opt))
log_level = atoi(value);
+ else if (!stricmp("lock_file", opt))
+ strcpy(lock_file, value);
else if (!stricmp("addr_prot", opt))
addr_prot = acm_convert_addr_prot(value);
else if (!stricmp("route_prot", opt))
@@ -2686,6 +2691,7 @@ static void acm_set_options(void)
static void acm_log_options(void)
{
acm_log(0, "log level %d\n", log_level);
+ acm_log(0, "lock file %s\n", lock_file);
acm_log(0, "address resolution %d\n", addr_prot);
acm_log(0, "route resolution %d\n", route_prot);
acm_log(0, "loopback resolution %d\n", loopback_prot);
@@ -2716,6 +2722,25 @@ static FILE *acm_open_log(void)
return f;
}
+static int acm_open_lock_file(void)
+{
+ int lock_fd;
+ char pid[16];
+
+ lock_fd = open(lock_file, O_RDWR | O_CREAT, 0640);
+ if (lock_fd < 0)
+ return lock_fd;
+
+ if (lockf(lock_fd, F_TLOCK, 0)) {
+ close(lock_fd);
+ return -1;
+ }
+
+ sprintf(pid, "%d\n", getpid());
+ write(lock_fd, pid, strlen(pid));
+ return 0;
+}
+
static void daemonize(void)
{
pid_t pid, sid;
@@ -2778,6 +2803,8 @@ int CDECL_FUNC main(int argc, char **argv)
return -1;
acm_set_options();
+ if (acm_open_lock_file())
+ return -1;
lock_init(&log_lock);
flog = acm_open_log();
diff --git a/src/acme.c b/src/acme.c
index 218dbe8..552f42a 100644
--- a/src/acme.c
+++ b/src/acme.c
@@ -106,6 +106,12 @@ static void gen_opts_temp(FILE *f)
fprintf(f, "\n");
fprintf(f, "log_level 0\n");
fprintf(f, "\n");
+ fprintf(f, "# lock_file:\n");
+ fprintf(f, "# Specifies the location of the ACM lock file used to
ensure that only a\n");
+ fprintf(f, "# single instance of ACM is running.\n");
+ fprintf(f, "\n");
+ fprintf(f, "lock_file /var/lock/ibacm.pid\n");
+ fprintf(f, "\n");
fprintf(f, "# addr_prot:\n");
fprintf(f, "# Default resolution protocol to resolve IP addresses into
IB GIDs.\n");
fprintf(f, "# Supported protocols are:\n");
--
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