Change the UST event hash table match function

[lttng-tools.git] / src / bin / lttng / conf.c

diff --git a/src/bin/lttng/conf.c b/src/bin/lttng/conf.c
index cdd264a5d11a3246e4430a3acce5cf354a68e731..7d537d1f6d654ab5dce83fa65adf333ed14e4bf4 100644 (file)
--- a/src/bin/lttng/conf.c
+++ b/src/bin/lttng/conf.c
@@ -2,9 +2,8 @@
  * Copyright (c)  2011 David Goulet <david.goulet@polymtl.ca>
  *
  * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * as published by the Free Software Foundation; only version 2
- * of the License.
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -30,9 +29,8 @@
 #include "conf.h"
 
 /*
- *  config_get_file_path
- *
- *  Return the path with '/CONFIG_FILENAME' added to it.
+ * Returns the path with '/CONFIG_FILENAME' added to it;
+ * path will be NULL if an error occurs.
  */
 char *config_get_file_path(char *path)
 {
@@ -48,9 +46,8 @@ char *config_get_file_path(char *path)
 }
 
 /*
- *  open_config
- *
- *  Return an open FILE pointer to the config file.
+ * Returns an open FILE pointer to the config file;
+ * on error, NULL is returned.
  */
 static FILE *open_config(char *path, const char *mode)
 {
@@ -75,9 +72,9 @@ error:
 }
 
 /*
- *  create_config_file
- *
- *  Create the empty config file a the path.
+ * Creates the empty config file at the path.
+ * On success, returns 0;
+ * on error, returns -1.
  */
 static int create_config_file(char *path)
 {
@@ -98,9 +95,9 @@ error:
 }
 
 /*
- *  write_config
- *
- *  Append data to the config file in file_path
+ * Append data to the config file in file_path
+ * On success, returns 0;
+ * on error, returns -1.
  */
 static int write_config(char *file_path, size_t size, char *data)
 {
@@ -116,7 +113,7 @@ static int write_config(char *file_path, size_t size, char *data)
 
        /* Write session name into config file */
        len = fwrite(data, size, 1, fp);
-       if (len < 1) {
+       if (len != 1) {
                ret = -1;
        }
        fclose(fp);
@@ -125,9 +122,7 @@ end:
 }
 
 /*
- *  config_get_default_path
- *
- *  Return the HOME directory path. Caller MUST NOT free(3) the return pointer.
+ * Returns the HOME directory path. Caller MUST NOT free(3) the return pointer.
  */
 char *config_get_default_path(void)
 {
@@ -135,9 +130,7 @@ char *config_get_default_path(void)
 }
 
 /*
- *  config_destroy
- *
- *  Destroy directory config and file config.
+ * Destroys directory config and file config.
  */
 void config_destroy(char *path)
 {
@@ -149,18 +142,50 @@ void config_destroy(char *path)
                return;
        }
 
+       if (!config_exists(config_path)) {
+               goto end;
+       }
+
+       DBG("Removing %s\n", config_path);
        ret = remove(config_path);
        if (ret < 0) {
                perror("remove config file");
        }
-
+end:
        free(config_path);
 }
 
 /*
- *  config_read_session_name
- *
- *  Return sesson name from the config file.
+ * Destroys the default config
+ */
+void config_destroy_default(void)
+{
+       char *path = config_get_default_path();
+       if (path == NULL) {
+               return;
+       }
+       config_destroy(path);
+}
+
+/*
+ * Returns 1 if config exists, 0 otherwise
+ */
+int config_exists(const char *path)
+{
+       int ret;
+       struct stat info;
+
+       ret = stat(path, &info);
+       if (ret < 0) {
+               return 0;
+       }
+       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)
 {
@@ -168,6 +193,12 @@ char *config_read_session_name(char *path)
        FILE *fp;
        char var[NAME_MAX], *session_name;
 
+       session_name = malloc(NAME_MAX);
+       if (session_name == NULL) {
+               ERR("Out of memory");
+               goto error;
+       }
+
        fp = open_config(path, "r");
        if (fp == NULL) {
                ERR("Can't find valid lttng config %s/.lttngrc", path);
@@ -175,7 +206,6 @@ char *config_read_session_name(char *path)
                goto error;
        }
 
-       session_name = malloc(NAME_MAX);
        while (!feof(fp)) {
                if ((ret = fscanf(fp, "%[^'=']=%s\n", var, session_name)) != 2) {
                        if (ret == -1) {
@@ -203,17 +233,22 @@ found:
 }
 
 /*
- *  config_add_session_name
- *
- *  Write session name option to the config file.
+ * Write session name option to the config file.
+ * On success, returns 0;
+ * on error, returns -1.
  */
 int config_add_session_name(char *path, char *name)
 {
        int ret;
        char session_name[NAME_MAX];
 
+       /*
+        * 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)
+        */
        ret = snprintf(session_name, NAME_MAX, "session=%s\n", name);
-       if (ret < 0) {
+       if ((ret < 0) || (ret >= NAME_MAX)) {
+               ret = -1;
                goto error;
        }
        ret = write_config(path, ret, session_name);
@@ -222,9 +257,9 @@ error:
 }
 
 /*
- *  config_init
- *
- *  Init configuration directory and file.
+ * Init configuration directory and file.
+ * On success, returns 0;
+ * on error, returns -1.
  */
 int config_init(char *session_name)
 {