[PATCH] xenpmd.c: use dynamic allocation

Manuel Bouyer posted 1 patch 2 weeks, 1 day ago
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git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20210112181242.1570-21-bouyer@antioche.eu.org
tools/xenpmd/xenpmd.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

[PATCH] xenpmd.c: use dynamic allocation

Posted by Manuel Bouyer 2 weeks, 1 day ago
From: Manuel Bouyer <bouyer@netbsd.org>

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 <bouyer@netbsd.org>
---
 tools/xenpmd/xenpmd.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

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;
-- 
2.29.2


Re: [PATCH] xenpmd.c: use dynamic allocation

Posted by Ian Jackson 12 hours ago
Manuel Bouyer writes ("[PATCH] xenpmd.c: use dynamic allocation"):
> From: Manuel Bouyer <bouyer@netbsd.org>
> 
> 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 <ian.jackson@eu.citrix.com>