Document and enforce return values

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

diff --git a/src/bin/lttng/conf.c b/src/bin/lttng/conf.c
index cdd264a5d11a3246e4430a3acce5cf354a68e731..00991b08195319f58f3d5489ff10ed679204f8aa 100644 (file)
--- a/src/bin/lttng/conf.c
+++ b/src/bin/lttng/conf.c
@@ -32,7 +32,8 @@
 /*
  *  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)
 {
@@ -50,7 +51,8 @@ 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)
 {
@@ -77,7 +79,9 @@ 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)
 {
@@ -101,6 +105,8 @@ error:
  *  write_config
  *
  *  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 +122,7 @@ 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);
@@ -127,7 +133,7 @@ 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)
 {
@@ -137,7 +143,7 @@ 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)
 {
@@ -160,7 +166,9 @@ void config_destroy(char *path)
 /*
  *  config_read_session_name
  *
- *  Return sesson name from the config file.
+ *  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 +176,12 @@ 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 +189,6 @@ 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) {
@@ -206,14 +219,21 @@ found:
  *  config_add_session_name
  *
  *  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);
@@ -225,6 +245,8 @@ error:
  *  config_init
  *
  *  Init configuration directory and file.
+ *  On success, returns 0;
+ *  on error, returns -1.
  */
 int config_init(char *session_name)
 {