[Xen-changelog] [xen staging] xenpmd: make 32 bit gcc 8.1 non-debug build work

[patchbot@xxxxxxx]

commit e75c9dc85fdeeeda0b98d8cd8d784e0508c3ffb8
Author:     Wei Liu <wei.liu2@xxxxxxxxxx>
AuthorDate: Thu Jul 26 15:58:54 2018 +0100
Commit:     Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Mon Aug 20 11:49:03 2018 +0100

    xenpmd: make 32 bit gcc 8.1 non-debug build work
    
    32 bit gcc 8.1 non-debug build yields:
    
    xenpmd.c:354:23: error: '%02x' directive output may be truncated writing 
between 2 and 8 bytes into a region of size 3 [-Werror=format-truncation=]
         snprintf(val, 3, "%02x",
                           ^~~~
    xenpmd.c:354:22: note: directive argument in the range [40, 2147483778]
         snprintf(val, 3, "%02x",
                          ^~~~~~
    xenpmd.c:354:5: note: 'snprintf' output between 3 and 9 bytes into a 
destination of size 3
         snprintf(val, 3, "%02x",
         ^~~~~~~~~~~~~~~~~~~~~~~~
                  (unsigned int)(9*4 +
                  ~~~~~~~~~~~~~~~~~~~~
                                 strlen(info->model_number) +
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                 strlen(info->serial_number) +
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                 strlen(info->battery_type) +
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                 strlen(info->oem_info) + 4));
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
    All info->* used in calculation are 32 bytes long, and the parsing
    code makes sure they are null-terminated, so the end result of the
    expression won't exceed 255, which should be able to be fit into 3
    bytes in hexadecimal format.
    
    Add an assertion to make gcc happy.
    
    Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 tools/xenpmd/xenpmd.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/xenpmd/xenpmd.c b/tools/xenpmd/xenpmd.c
index 56412a9a81..1c801caa71 100644
--- a/tools/xenpmd/xenpmd.c
+++ b/tools/xenpmd/xenpmd.c
@@ -40,6 +40,7 @@
 #include <unistd.h>
 #include <sys/stat.h>
 #include <xenstore.h>
+#include <assert.h>
 
 /* #define RUN_STANDALONE */
 #define RUN_IN_SIMULATE_MODE
@@ -345,18 +346,17 @@ void write_ulong_lsb_first(char *temp_val, unsigned long 
val)
 void write_battery_info_to_xenstore(struct battery_info *info)
 {
     char val[1024], string_info[256];
+    unsigned int len;
 
     xs_mkdir(xs, XBT_NULL, "/pm");
    
     memset(val, 0, 1024);
     memset(string_info, 0, 256);
     /* write 9 dwords (so 9*4) + length of 4 strings + 4 null terminators */
-    snprintf(val, 3, "%02x", 
-             (unsigned int)(9*4 +
-                            strlen(info->model_number) +
-                            strlen(info->serial_number) +
-                            strlen(info->battery_type) +
-                            strlen(info->oem_info) + 4));
+    len = 9 * 4 + strlen(info->model_number) + strlen(info->serial_number) +
+          strlen(info->battery_type) + strlen(info->oem_info) + 4;
+    assert(len < 255);
+    snprintf(val, 3, "%02x", len);
     write_ulong_lsb_first(val+2, info->present);
     write_ulong_lsb_first(val+10, info->design_capacity);
     write_ulong_lsb_first(val+18, info->last_full_capacity);
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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