diff options
Diffstat (limited to 'external/meta-virtualization/recipes-extended/xen/files/xen-tools-xenpmd-snprintf.patch')
| -rw-r--r-- | external/meta-virtualization/recipes-extended/xen/files/xen-tools-xenpmd-snprintf.patch | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/external/meta-virtualization/recipes-extended/xen/files/xen-tools-xenpmd-snprintf.patch b/external/meta-virtualization/recipes-extended/xen/files/xen-tools-xenpmd-snprintf.patch new file mode 100644 index 00000000..aac7282f --- /dev/null +++ b/external/meta-virtualization/recipes-extended/xen/files/xen-tools-xenpmd-snprintf.patch @@ -0,0 +1,78 @@ +From e4d78a67ffbacf30b66464080898227f18f6bf49 Mon Sep 17 00:00:00 2001 +From: Christopher Clark <christopher.w.clark@gmail.com> +Date: Fri, 17 Aug 2018 17:46:10 -0700 +Subject: [PATCH] xenpmd: prevent format-truncation warning with gcc 8.2 + ARM + 32-bit +To: xen-devel@lists.xenproject.org +Cc: ian.jackson@eu.citrix.com, + wei.liu2@citrix.com + +xenpmd writes battery information to xenstore, including a string with a +formatted hex value calculated from summing the lengths of four strings, +plus some constants. + +Each of the four strings has a maximum length of 31 bytes, excluding the +terminating zero byte. The strings are stored in 32-byte arrays in a +struct that is zeroed before it is populated, and logic that writes to +the strings uses strncpy and explicit zero termination. + +The maximum value to be supplied to the xenstore string is: + (9 * 4) + (31 * 4) + 4 , which is 164, ie. 0xa4. + +When used with this value, '%02x' will always fit within 3 bytes, but +gcc 8.2 is apparently not able to deduce this (observed when building +for a 32-bit ARM platform). + +This commit assists the compiler by applying a mask (0xff) to the value, +enabling it to observe a lower maximum value and so pass the truncation +length check. + +Prior to this change, building fails with the compiler warning: + +| xenpmd.c: In function 'write_battery_info_to_xenstore': +| 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)); +| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +| cc1: all warnings being treated as errors + +Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com> +--- + tools/xenpmd/xenpmd.c | 6 ++++-- + 1 file changed, 4 insertions(+), 2 deletions(-) + +diff --git a/tools/xenpmd/xenpmd.c b/tools/xenpmd/xenpmd.c +index 56412a9..0c0787e 100644 +--- a/tools/xenpmd/xenpmd.c ++++ b/tools/xenpmd/xenpmd.c +@@ -350,8 +350,10 @@ void write_battery_info_to_xenstore(struct battery_info *info) + + 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", ++ /* write 9 dwords (so 9*4) + length of 4 strings + 4 null terminators. ++ * mask informs the compiler that format truncation will not occur. ++ */ ++ snprintf(val, 3, "%02x", 0xff & + (unsigned int)(9*4 + + strlen(info->model_number) + + strlen(info->serial_number) + |