[lttng-dev] [RFC PATCH lttng-tools] Allow environment variable LTTNG_HOME to override HOME - for lttng-tools - UPDATED PATCH

Amit Margalit AMITM at il.ibm.com
Thu Jun 13 08:15:39 EDT 2013


Hi,

I've added a paragraph to the man page. Here is the new patch:

>From a72bd9dd6a58ac727280f2f9a85ee80607f1aba9 Mon Sep 17 00:00:00 2001
From: Amit Margalit <amitm at il.ibm.com>
Date: Thu, 13 Jun 2013 12:35:13 +0300
Subject: [PATCH] Using LTTNG_HOME environment variable if exists, with
 fallback to HOME

---
 doc/man/lttng.1                 |  4 ++++
 src/bin/lttng-relayd/utils.c    | 10 +---------
 src/bin/lttng-sessiond/main.c   |  2 +-
 src/bin/lttng-sessiond/utils.c  | 10 ----------
 src/bin/lttng/commands/create.c |  2 +-
 src/bin/lttng/conf.c            | 13 +++----------
 src/bin/lttng/conf.h            |  1 -
 src/bin/lttng/utils.c           |  3 ++-
 src/common/defaults.h           |  2 ++
 src/common/utils.c              | 15 +++++++++++++++
 src/common/utils.h              |  1 +
 src/lib/lttng-ctl/lttng-ctl.c   |  5 +++--
 12 files changed, 33 insertions(+), 35 deletions(-)

diff --git a/doc/man/lttng.1 b/doc/man/lttng.1
index f472d38..26fd44a 100644
--- a/doc/man/lttng.1
+++ b/doc/man/lttng.1
@@ -214,6 +214,10 @@ automatically created having this form: 
'auto-yyyymmdd-hhmmss'.
 
 If no \fB\-o, \-\-output\fP is specified, the traces will be written in
 $HOME/lttng-traces.
+
+The $HOME environment variable can be overridden by defining the 
environment
+variable LTTNG_HOME. This is useful when the user running the commands 
has
+a non-writeable home directory.
 .fi
 
 .B OPTIONS:
diff --git a/src/bin/lttng-relayd/utils.c b/src/bin/lttng-relayd/utils.c
index ad13d32..392fab6 100644
--- a/src/bin/lttng-relayd/utils.c
+++ b/src/bin/lttng-relayd/utils.c
@@ -29,14 +29,6 @@
 #include "lttng-relayd.h"
 #include "utils.h"
 
-/*
- * Returns the HOME directory path. Caller MUST NOT free(3) the return 
pointer.
- */
-static char *get_default_path(void)
-{
-       return getenv("HOME");
-}
-
 static char *create_output_path_auto(char *path_name)
 {
        int ret;
@@ -44,7 +36,7 @@ static char *create_output_path_auto(char *path_name)
        char *alloc_path = NULL;
        char *default_path;
 
-       default_path = get_default_path();
+       default_path = utils_get_home_dir();
        if (default_path == NULL) {
                ERR("Home path not found.\n \
                                Please specify an output path using -o, 
--output PATH");
diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index 4470afc..256ffba 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -4136,7 +4136,7 @@ int main(int argc, char **argv)
                DBG2("Kernel consumer cmd path: %s",
                                kconsumer_data.cmd_unix_sock_path);
        } else {
-               home_path = get_home_dir();
+               home_path = utils_get_home_dir();
                if (home_path == NULL) {
                        /* TODO: Add --socket PATH option */
                        ERR("Can't get HOME directory for sockets 
creation.");
diff --git a/src/bin/lttng-sessiond/utils.c 
b/src/bin/lttng-sessiond/utils.c
index 5ea3374..af42ad0 100644
--- a/src/bin/lttng-sessiond/utils.c
+++ b/src/bin/lttng-sessiond/utils.c
@@ -45,13 +45,3 @@ int notify_thread_pipe(int wpipe)
 
        return ret;
 }
-
-/*
- * Return pointer to home directory path using the env variable HOME.
- *
- * No home, NULL is returned.
- */
-const char *get_home_dir(void)
-{
-       return ((const char *) getenv("HOME"));
-}
diff --git a/src/bin/lttng/commands/create.c 
b/src/bin/lttng/commands/create.c
index 805cdb1..ddd2983 100644
--- a/src/bin/lttng/commands/create.c
+++ b/src/bin/lttng/commands/create.c
@@ -250,7 +250,7 @@ static int create_session(void)
                print_str_url = url;
        } else {
                /* Auto output path */
-               alloc_path = config_get_default_path();
+               alloc_path = utils_get_home_dir();
                if (alloc_path == NULL) {
                        ERR("HOME path not found.\n \
                                        Please specify an output path 
using -o, --output PATH");
diff --git a/src/bin/lttng/conf.c b/src/bin/lttng/conf.c
index b6632fc..5a0da9d 100644
--- a/src/bin/lttng/conf.c
+++ b/src/bin/lttng/conf.c
@@ -25,6 +25,7 @@
 #include <unistd.h>
 
 #include <common/error.h>
+#include <common/utils.h>
 
 #include "conf.h"
 
@@ -123,14 +124,6 @@ end:
 }
 
 /*
- * Returns the HOME directory path. Caller MUST NOT free(3) the return 
pointer.
- */
-char *config_get_default_path(void)
-{
-       return getenv("HOME");
-}
-
-/*
  * Destroys directory config and file config.
  */
 void config_destroy(char *path)
@@ -161,7 +154,7 @@ end:
  */
 void config_destroy_default(void)
 {
-       char *path = config_get_default_path();
+       char *path = utils_get_home_dir();
        if (path == NULL) {
                return;
        }
@@ -277,7 +270,7 @@ int config_init(char *session_name)
        int ret;
        char *path;
 
-       path = config_get_default_path();
+       path = utils_get_home_dir();
        if (path == NULL) {
                ret = -1;
                goto error;
diff --git a/src/bin/lttng/conf.h b/src/bin/lttng/conf.h
index 2cb04b0..3bed59c 100644
--- a/src/bin/lttng/conf.h
+++ b/src/bin/lttng/conf.h
@@ -25,7 +25,6 @@ void config_destroy_default(void);
 int config_exists(const char *path);
 int config_init(char *path);
 int config_add_session_name(char *path, char *name);
-char *config_get_default_path(void);
 
 /* Must free() the return pointer */
 char *config_read_session_name(char *path);
diff --git a/src/bin/lttng/utils.c b/src/bin/lttng/utils.c
index 94c4527..6041655 100644
--- a/src/bin/lttng/utils.c
+++ b/src/bin/lttng/utils.c
@@ -21,6 +21,7 @@
 #include <limits.h>
 
 #include <common/error.h>
+#include <common/utils.h>
 
 #include "conf.h"
 #include "utils.h"
@@ -36,7 +37,7 @@ char *get_session_name(void)
        char *path, *session_name = NULL;
 
        /* Get path to config file */
-       path = config_get_default_path();
+       path = utils_get_home_dir();
        if (path == NULL) {
                goto error;
        }
diff --git a/src/common/defaults.h b/src/common/defaults.h
index 66bb972..c040634 100644
--- a/src/common/defaults.h
+++ b/src/common/defaults.h
@@ -77,6 +77,8 @@
 #define DEFAULT_USTCONSUMERD32_ERR_SOCK_PATH DEFAULT_USTCONSUMERD32_PATH 
"/error"
 
 /* Default lttng run directory */
+#define DEFAULT_LTTNG_HOME_ENV_VAR              "LTTNG_HOME"
+#define DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR    "HOME"
 #define DEFAULT_LTTNG_RUNDIR                    "/var/run/lttng"
 #define DEFAULT_LTTNG_HOME_RUNDIR               "%s/.lttng"
 #define DEFAULT_LTTNG_SESSIOND_PIDFILE          "lttng-sessiond.pid"
diff --git a/src/common/utils.c b/src/common/utils.c
index 38f78a7..436febe 100644
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -32,6 +32,7 @@
 #include <common/runas.h>
 
 #include "utils.h"
+#include "defaults.h"
 
 /*
  * Return the realpath(3) of the path even if the last directory token 
does not
@@ -584,3 +585,17 @@ int utils_get_count_order_u32(uint32_t x)
 
        return fls_u32(x - 1);
 }
+
+/**
+ * Obtain the value of LTTNG_HOME environment variable, if exists.
+ * Otherwise returns the value of HOME.
+ */
+char *utils_get_home_dir(void)
+{
+       char *val = NULL;
+       val = getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
+       if (val != NULL) {
+               return val;
+       }
+       return getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
+}
diff --git a/src/common/utils.h b/src/common/utils.h
index 083acef..9e6fb37 100644
--- a/src/common/utils.h
+++ b/src/common/utils.h
@@ -40,5 +40,6 @@ int utils_rotate_stream_file(char *path_name, char 
*file_name, uint64_t size,
                uint64_t count, int uid, int gid, int out_fd, uint64_t 
*new_count);
 int utils_parse_size_suffix(char *str, uint64_t *size);
 int utils_get_count_order_u32(uint32_t x);
+char *utils_get_home_dir(void);
 
 #endif /* _COMMON_UTILS_H */
diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index a7328eb..9d76f79 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -32,6 +32,7 @@
 #include <common/defaults.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 #include <common/uri.h>
+#include <common/utils.h>
 #include <lttng/lttng.h>
 
 #include "filter/filter-ast.h"
@@ -485,7 +486,7 @@ static int set_session_daemon_path(void)
                 * With GNU C >= 2.1, snprintf returns the required size 
(excluding closing null)
                 */
                ret = snprintf(sessiond_sock_path, 
sizeof(sessiond_sock_path),
-                               DEFAULT_HOME_CLIENT_UNIX_SOCK, 
getenv("HOME"));
+                               DEFAULT_HOME_CLIENT_UNIX_SOCK, 
utils_get_home_dir());
                if ((ret < 0) || (ret >= sizeof(sessiond_sock_path))) {
                        goto error;
                }
@@ -1543,7 +1544,7 @@ static int set_health_socket_path(void)
                 * With GNU C <  2.1, snprintf returns -1 if the target 
buffer is too small;
                 * With GNU C >= 2.1, snprintf returns the required size 
(excluding closing null)
                 */
-               home = getenv("HOME");
+               home = utils_get_home_dir();
                if (home == NULL) {
                        /* Fallback in /tmp .. */
                        home = "/tmp";
-- 
1.7.11.7


Amit Margalit
IBM XIV - Storage Reinvented
XIV-NAS Development Team
Tel. 03-689-7774
Fax. 03-689-7230



From:   Amit Margalit/Israel/IBM at IBMIL
To:     David Goulet <dgoulet at efficios.com>
Cc:     lttng-dev at lists.lttng.org
Date:   06/13/2013 12:39 PM
Subject:        Re: [lttng-dev] [RFC PATCH lttng-tools] Allow environment 
variable LTTNG_HOME to override HOME - for lttng-tools



I think I've done all that you suggested, for lttng-tools only, though, 
based on cfa9a5a2b4a96e0d6a9eeddd2622a6d7c173b7ac which is the latest 
master as of right now. 

Here is the patch: 
>From 5881718a60608d640ac1124c9c1f439a2a084707 Mon Sep 17 00:00:00 2001
From: Amit Margalit <amitm at il.ibm.com>
Date: Thu, 13 Jun 2013 12:35:13 +0300
Subject: [PATCH] Using LTTNG_HOME environment variable if exists, with
fallback to HOME 

---
[Old patch deleted]
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