| Message ID | 0ade4264c537819c3dd45179fcea2723df66b045.1602672245.git.bertrand.marquis@arm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tools/xenmpd: Fix gcc10 snprintf warning | expand |
Hi, On 14/10/2020 11:47, Bertrand Marquis wrote: > Add a check for snprintf return code and ignore the entry if we get an > error. This should in fact never happen and is more a trick to make gcc > happy and prevent compilation errors. > > This is solving the gcc warning: > xenpmd.c:92:37: error: '%s' directive output may be truncated writing > between 4 and 2147483645 bytes into a region of size 271 > [-Werror=format-truncation=] IIRC, this is only affecting GCC when building for Arm32 *and* when the optimizer is enabled. If so, it would be good to add more details in the commit message. I would also suggest to link to the bug reported on Debian. Cheers, > > Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com> > --- > tools/xenpmd/xenpmd.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/tools/xenpmd/xenpmd.c b/tools/xenpmd/xenpmd.c > index 35fd1c931a..12b82cf43e 100644 > --- a/tools/xenpmd/xenpmd.c > +++ b/tools/xenpmd/xenpmd.c > @@ -102,6 +102,7 @@ FILE *get_next_battery_file(DIR *battery_dir, > FILE *file = 0; > struct dirent *dir_entries; > char file_name[284]; > + int ret; > > do > { > @@ -111,11 +112,15 @@ FILE *get_next_battery_file(DIR *battery_dir, > if ( strlen(dir_entries->d_name) < 4 ) > continue; > if ( battery_info_type == BIF ) > - snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH, > + ret = snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH, > dir_entries->d_name); > else > - snprintf(file_name, sizeof(file_name), BATTERY_STATE_FILE_PATH, > + ret = snprintf(file_name, sizeof(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"); > } while ( !file ); > > Cheers,
Hi Julien, > On 14 Oct 2020, at 12:04, Julien Grall <julien@xen.org> wrote: > > Hi, > > On 14/10/2020 11:47, Bertrand Marquis wrote: >> Add a check for snprintf return code and ignore the entry if we get an >> error. This should in fact never happen and is more a trick to make gcc >> happy and prevent compilation errors. >> This is solving the gcc warning: >> xenpmd.c:92:37: error: '%s' directive output may be truncated writing >> between 4 and 2147483645 bytes into a region of size 271 >> [-Werror=format-truncation=] > > IIRC, this is only affecting GCC when building for Arm32 *and* when the optimizer is enabled. If so, it would be good to add more details in the commit message. I can confirm this is the only build catching it on my side. I will modify the commit message to say that the problem was encountered on arm32 build with the optimizer enabled. > > I would also suggest to link to the bug reported on Debian. I will add it to the commit message. Cheers Bertrand > > Cheers, > >> Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com> >> --- >> tools/xenpmd/xenpmd.c | 9 +++++++-- >> 1 file changed, 7 insertions(+), 2 deletions(-) >> diff --git a/tools/xenpmd/xenpmd.c b/tools/xenpmd/xenpmd.c >> index 35fd1c931a..12b82cf43e 100644 >> --- a/tools/xenpmd/xenpmd.c >> +++ b/tools/xenpmd/xenpmd.c >> @@ -102,6 +102,7 @@ FILE *get_next_battery_file(DIR *battery_dir, >> FILE *file = 0; >> struct dirent *dir_entries; >> char file_name[284]; >> + int ret; >> do >> { >> @@ -111,11 +112,15 @@ FILE *get_next_battery_file(DIR *battery_dir, >> if ( strlen(dir_entries->d_name) < 4 ) >> continue; >> if ( battery_info_type == BIF ) >> - snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH, >> + ret = snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH, >> dir_entries->d_name); >> else >> - snprintf(file_name, sizeof(file_name), BATTERY_STATE_FILE_PATH, >> + ret = snprintf(file_name, sizeof(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"); >> } while ( !file ); >> > > Cheers, > > -- > Julien Grall
diff --git a/tools/xenpmd/xenpmd.c b/tools/xenpmd/xenpmd.c index 35fd1c931a..12b82cf43e 100644 --- a/tools/xenpmd/xenpmd.c +++ b/tools/xenpmd/xenpmd.c @@ -102,6 +102,7 @@ FILE *get_next_battery_file(DIR *battery_dir, FILE *file = 0; struct dirent *dir_entries; char file_name[284]; + int ret; do { @@ -111,11 +112,15 @@ FILE *get_next_battery_file(DIR *battery_dir, if ( strlen(dir_entries->d_name) < 4 ) continue; if ( battery_info_type == BIF ) - snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH, + ret = snprintf(file_name, sizeof(file_name), BATTERY_INFO_FILE_PATH, dir_entries->d_name); else - snprintf(file_name, sizeof(file_name), BATTERY_STATE_FILE_PATH, + ret = snprintf(file_name, sizeof(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"); } while ( !file );
Add a check for snprintf return code and ignore the entry if we get an error. This should in fact never happen and is more a trick to make gcc happy and prevent compilation errors. This is solving the gcc warning: xenpmd.c:92:37: error: '%s' directive output may be truncated writing between 4 and 2147483645 bytes into a region of size 271 [-Werror=format-truncation=] Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com> --- tools/xenpmd/xenpmd.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)