Fix: destroy session removes the default config file

Destroy session command by default removes the default config file
without checking the current session. As a result when we call any
other command which expects a default session by calling
get_session_name() function, it fails.

This patch will fix this by checking that the default config file gets
removed only when destroy session is called with the current session.

Fixes: #887
Signed-off-by: Partha Pratim Mukherjee <ppm.floss@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng/commands/destroy.c b/src/bin/lttng/commands/destroy.c
index 95343c9c9a883513dd2741e5a1cb68acb2e612a3..53fe3aca13b676c6f94e4b64c912191bfb5bfe15 100644 (file)
--- a/src/bin/lttng/commands/destroy.c
+++ b/src/bin/lttng/commands/destroy.c
@@ -29,6 +29,7 @@
 
 #include <common/mi-lttng.h>
 #include <common/sessiond-comm/sessiond-comm.h>
+#include <common/utils.h>
 
 static char *opt_session_name;
 static int opt_destroy_all;
@@ -75,6 +76,7 @@ static void usage(FILE *ofp)
 static int destroy_session(struct lttng_session *session)
 {
        int ret;
+       char *session_name = NULL;
 
        ret = lttng_destroy_session(session->name);
        if (ret < 0) {
@@ -90,7 +92,11 @@ static int destroy_session(struct lttng_session *session)
        }
 
        MSG("Session %s destroyed", session->name);
-       config_destroy_default();
+
+       session_name = get_session_name_quiet();
+       if (session_name && !strncmp(session->name, session_name, NAME_MAX)) {
+               config_destroy_default();
+       }
 
        if (lttng_opt_mi) {
                ret = mi_lttng_session(writer, session, 0);
@@ -102,6 +108,7 @@ static int destroy_session(struct lttng_session *session)
 
        ret = CMD_SUCCESS;
 error:
+       free(session_name);
        return ret;
 }
 
@@ -213,7 +220,7 @@ int cmd_destroy(int argc, const char **argv)
        } else {
                opt_session_name = (char *) poptGetArg(pc);
 
-               if (opt_session_name == NULL) {
+               if (!opt_session_name) {
                        /* No session name specified, lookup default */
                        session_name = get_session_name();
                        if (session_name == NULL) {

diff --git a/src/bin/lttng/conf.c b/src/bin/lttng/conf.c
index 7e6c833449857890fa7c8e8a092eaf97d439a750..f96be3a8175a248e8c1e6187e8e5fc5e96c8b270 100644 (file)
--- a/src/bin/lttng/conf.c
+++ b/src/bin/lttng/conf.c
@@ -24,6 +24,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <errno.h>
 
 #include <common/common.h>
 #include <common/utils.h>
@@ -177,14 +178,10 @@ int config_exists(const char *path)
        return S_ISREG(info.st_mode) || S_ISDIR(info.st_mode);
 }
 
-/*
- * Returns the session name from the config file.
- * The caller is responsible for freeing the returned string.
- * On error, NULL is returned.
- */
-char *config_read_session_name(char *path)
+static
+int _config_read_session_name(char *path, char **name)
 {
-       int ret;
+       int ret = 0;
        FILE *fp;
        char var[NAME_MAX], *session_name;
 #if (NAME_MAX == 255)
@@ -193,15 +190,14 @@ char *config_read_session_name(char *path)
 
        session_name = zmalloc(NAME_MAX);
        if (session_name == NULL) {
+               ret = -ENOMEM;
                ERR("Out of memory");
                goto error;
        }
 
        fp = open_config(path, "r");
        if (fp == NULL) {
-               ERR("Can't find valid lttng config %s/.lttngrc", path);
-               MSG("Did you create a session? (lttng create <my_session>)");
-               free(session_name);
+               ret = -ENOENT;
                goto error;
        }
 
@@ -222,22 +218,54 @@ char *config_read_session_name(char *path)
        }
 
 error_close:
-       free(session_name);
-       ret = fclose(fp);
-       if (ret < 0) {
+       if (fclose(fp) < 0) {
                PERROR("close config read session name");
        }
-
 error:
-       return NULL;
-
+       free(session_name);
+       return ret;
 found:
-       ret = fclose(fp);
-       if (ret < 0) {
+       *name = session_name;
+       if (fclose(fp) < 0) {
                PERROR("close config read session name found");
        }
-       return session_name;
+       return ret;
+}
+
+/*
+ * Returns the session name from the config file.
+ *
+ * The caller is responsible for freeing the returned string.
+ * On error, NULL is returned.
+ */
+char *config_read_session_name(char *path)
+{
+       int ret;
+       char *name = NULL;
+
+       ret = _config_read_session_name(path, &name);
+       if (ret == -ENOENT) {
+               const char *home_dir = utils_get_home_dir();
+
+               ERR("Can't find valid lttng config %s/.lttngrc", home_dir);
+               MSG("Did you create a session? (lttng create <my_session>)");
+       }
+
+       return name;
+}
+
+/*
+ * Returns the session name from the config file. (no warnings/errors emitted)
+ *
+ * The caller is responsible for freeing the returned string.
+ * On error, NULL is returned.
+ */
+char *config_read_session_name_quiet(char *path)
+{
+       char *name = NULL;
 
+       (void) _config_read_session_name(path, &name);
+       return name;
 }
 
 /*

diff --git a/src/bin/lttng/conf.h b/src/bin/lttng/conf.h
index 3bed59c2a09a58bc2c56e5c01c107fe74d4571e7..a26a6b8e31f9a807b282780d7e3cd706852b2942 100644 (file)
--- a/src/bin/lttng/conf.h
+++ b/src/bin/lttng/conf.h
@@ -28,6 +28,7 @@ int config_add_session_name(char *path, char *name);
 
 /* Must free() the return pointer */
 char *config_read_session_name(char *path);
+char *config_read_session_name_quiet(char *path);
 char *config_get_file_path(char *path);
 
 #endif /* _LTTNG_CONFIG_H */

diff --git a/src/bin/lttng/utils.c b/src/bin/lttng/utils.c
index ef8d0235a019229cf0c4c1b92c33a58275f8a6de..d52d4622a9c3f3b1dfa34decf94d20bceaa8ecfa 100644 (file)
--- a/src/bin/lttng/utils.c
+++ b/src/bin/lttng/utils.c
@@ -40,13 +40,8 @@ static const char *str_jul = "JUL";
 static const char *str_log4j = "LOG4J";
 static const char *str_python = "Python";
 
-/*
- *  get_session_name
- *
- *  Return allocated string with the session name found in the config
- *  directory.
- */
-char *get_session_name(void)
+static
+char *_get_session_name(int quiet)
 {
        char *path, *session_name = NULL;
 
@@ -57,7 +52,8 @@ char *get_session_name(void)
        }
 
        /* Get session name from config */
-       session_name = config_read_session_name(path);
+       session_name = quiet ? config_read_session_name_quiet(path) :
+               config_read_session_name(path);
        if (session_name == NULL) {
                goto error;
        }
@@ -70,6 +66,28 @@ error:
        return NULL;
 }
 
+/*
+ *  get_session_name
+ *
+ *  Return allocated string with the session name found in the config
+ *  directory.
+ */
+char *get_session_name(void)
+{
+       return _get_session_name(0);
+}
+
+/*
+ *  get_session_name_quiet (no warnings/errors emitted)
+ *
+ *  Return allocated string with the session name found in the config
+ *  directory.
+ */
+char *get_session_name_quiet(void)
+{
+       return _get_session_name(1);
+}
+
 /*
  *  list_commands
  *

diff --git a/src/bin/lttng/utils.h b/src/bin/lttng/utils.h
index d3941279a316d1c306d2dacd2ba839ae70db0a64..ea92bb9bc0cf2968ab588aba7eacfda1ebbde459 100644 (file)
--- a/src/bin/lttng/utils.h
+++ b/src/bin/lttng/utils.h
@@ -28,6 +28,7 @@ extern char *opt_relayd_path;
 struct cmd_struct;
 
 char *get_session_name(void);
+char *get_session_name_quiet(void);
 void list_commands(struct cmd_struct *commands, FILE *ofp);
 void list_cmd_options(FILE *ofp, struct poptOption *options);