service: if logging start app with LD_PRELOAD & lib for line buffering

[project/procd.git] / service / instance.c

diff --git a/service/instance.c b/service/instance.c
index 35b2def..40ff021 100644 (file)
--- a/service/instance.c
+++ b/service/instance.c
@@ -12,6 +12,7 @@
  * GNU General Public License for more details.
  */
 
+#define _GNU_SOURCE
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -19,6 +20,7 @@
 #include <net/if.h>
 #include <unistd.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <fcntl.h>
 #include <pwd.h>
 #include <libgen.h>
@@ -224,8 +226,11 @@ instance_run(struct service_instance *in, int _stdout, int _stderr)
        struct blobmsg_list_node *var;
        struct blob_attr *cur;
        char **argv;
+       char *ld_preload;
        int argc = 1; /* NULL terminated */
        int rem, _stdin;
+       bool seccomp = !in->trace && !in->has_jail && in->seccomp;
+       bool setlbf = _stdout >= 0;
 
        if (in->nice)
                setpriority(PRIO_PROCESS, 0, in->nice);
@@ -236,10 +241,14 @@ instance_run(struct service_instance *in, int _stdout, int _stderr)
        blobmsg_list_for_each(&in->env, var)
                setenv(blobmsg_name(var->data), blobmsg_data(var->data), 1);
 
-       if (!in->trace && !in->has_jail && in->seccomp) {
+       if (seccomp)
                setenv("SECCOMP_FILE", in->seccomp, 1);
-               setenv("LD_PRELOAD", "/lib/libpreload-seccomp.so", 1);
-       }
+
+       if ((seccomp || setlbf) && asprintf(&ld_preload, "LD_PRELOAD=%s%s%s",
+                       seccomp ? "/lib/libpreload-seccomp.so" : "",
+                       seccomp && setlbf ? ":" : "",
+                       setlbf ? "/lib/libsetlbf.so" : "") > 0)
+               putenv(ld_preload);
 
        blobmsg_list_for_each(&in->limits, var)
                instance_limits(blobmsg_name(var->data), blobmsg_data(var->data));