xenpmd.c: use dynamic allocation

Commit Message

Manuel Bouyer Jan. 12, 2021, 6:12 p.m. UTC

From: Manuel Bouyer <[e-mail]>

On NetBSD, d_name is larger than 256, so file_name[284] may not be large
enough (and gcc emits a format-truncation error).
Use asprintf() instead of snprintf() on a static on-stack buffer.

Signed-off-by: Manuel Bouyer <[e-mail]>
---
 tools/xenpmd/xenpmd.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Ian Jackson Jan. 27, 2021, 3:57 p.m. UTC | #1

Manuel Bouyer writes ("[PATCH] xenpmd.c: use dynamic allocation"):
> From: Manuel Bouyer <[e-mail]>
> 
> On NetBSD, d_name is larger than 256, so file_name[284] may not be large
> enough (and gcc emits a format-truncation error).
> Use asprintf() instead of snprintf() on a static on-stack buffer.

Reviewed-by: Ian Jackson <[e-mail]>

Patch

diff --git a/tools/xenpmd/xenpmd.c b/tools/xenpmd/xenpmd.c
index 12b82cf43e..e432aad856 100644
--- a/tools/xenpmd/xenpmd.c
+++ b/tools/xenpmd/xenpmd.c
@@ -101,7 +101,7 @@  FILE *get_next_battery_file(DIR *battery_dir,
 {
     FILE *file = 0;
     struct dirent *dir_entries;
-    char file_name[284];
+    char *file_name;
     int ret;
     
     do 
@@ -112,16 +112,16 @@  FILE *get_next_battery_file(DIR *battery_dir,
         if ( strlen(dir_entries->d_name) < 4 )
             continue;
         if ( battery_info_type == BIF ) 
-            ret = snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH,
+            ret = asprintf(&file_name, BATTERY_INFO_FILE_PATH,
                      dir_entries->d_name);
         else 
-            ret = snprintf(file_name, sizeof(file_name), BATTERY_STATE_FILE_PATH,
+            ret = asprintf(&file_name, BATTERY_STATE_FILE_PATH,
                      dir_entries->d_name);
         /* This should not happen but is needed to pass gcc checks */
         if (ret < 0)
             continue;
-        file_name[sizeof(file_name) - 1] = '\0';
         file = fopen(file_name, "r");
+	free(file_name);
     } while ( !file );
 
     return file;