From: Amit Margalit <AMITM@il.ibm.com>
Date: Mon, 8 Jul 2013 16:10:31 +0000 (-0400)
Subject: Allow environment variable LTTNG_HOME to override HOME
X-Git-Tag: v2.3.0-rc1~7
X-Git-Url: http://git.lttng.org/?p=lttng-ust.git;a=commitdiff_plain;h=3c6f6263bb2d87dc863c24a4edc59c2c959270b0

Allow environment variable LTTNG_HOME to override HOME

Patch functionality - If LTTNG_HOME environment variable exists, it is
used instead of HOME.  Reason for patch - We are trying to deploy LTTng
on a system where $HOME is on a filesystem mounted read-only, but cannot
afford to run lttng as a different user and cannot move the home
directories of users to writeable locations.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 60beef8f..475110cf 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -188,6 +188,22 @@ extern void lttng_ring_buffer_client_discard_exit(void);
 extern void lttng_ring_buffer_client_discard_rt_exit(void);
 extern void lttng_ring_buffer_metadata_client_exit(void);
 
+/*
+ * Returns the HOME directory path. Caller MUST NOT free(3) the returned
+ * pointer.
+ */
+static
+const char *get_lttng_home_dir(void)
+{
+       const char *val;
+
+       val = (const char *) getenv("LTTNG_HOME");
+       if (val != NULL) {
+               return val;
+       }
+       return (const char *) getenv("HOME");
+}
+
 /*
  * Force a read (imply TLS fixup for dlopen) of TLS variables.
  */
@@ -232,7 +248,7 @@ int setup_local_apps(void)
 		assert(local_apps.allowed == 0);
 		return 0;
 	}
-	home_dir = (const char *) getenv("HOME");
+	home_dir = get_lttng_home_dir();
 	if (!home_dir) {
 		WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
 		assert(local_apps.allowed == 0);