| Message ID | 20180125131455.14466-1-frediz@linux.vnet.ibm.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Fix FTBFS with -Werror=format-overflow | expand |
On 26/01/18 00:14, Frédéric Bonnard wrote: > i2c.c fails to compile with gcc7 and -Werror=format-overflow used in > Debian Unstable and Ubuntu 18.04 : > > i2c.c: In function ‘i2c_init’: > i2c.c:211:15: error: ‘%s’ directive writing up to 255 bytes into a > region of size 236 [-Werror=format-overflow=] > > We just make sure we never write more than what the destination can > store. > > Signed-off-by: Frédéric Bonnard <frediz@linux.vnet.ibm.com> > --- > external/opal-prd/i2c.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/external/opal-prd/i2c.c b/external/opal-prd/i2c.c > index ba4b3c85..dca303e4 100644 > --- a/external/opal-prd/i2c.c > +++ b/external/opal-prd/i2c.c > @@ -234,7 +234,13 @@ void i2c_init(void) > continue; > > /* Get bus name */ > - sprintf(dpath, SYSFS "/class/i2c-dev/%s/name", devent->d_name); > + if (snprintf(dpath, NAME_MAX, SYSFS "/class/i2c-dev/%s/name", > + devent->d_name) < 0 ) { If the string is too long, snprintf() will truncate and return number of bytes written, not a negative error code. > + pr_log(LOG_ERR, "I2C: bus name longer than NAME_MAX : " Strictly speaking, the bus name doesn't have to be longer than NAME_MAX, it's the entire path. I suspect that dpath should actually be of length PATH_MAX... Andrew > + SYSFS "/class/i2c-dev/%s/name", > + devent->d_name); > + return; > + } > f = fopen(dpath, "r"); > if (!f) { > pr_log(LOG_NOTICE, "I2C: Can't open %s: %m, skipping.", >
Hi Andrew, On Tue, 30 Jan 2018 13:28:24 +1100, Andrew Donnellan <andrew.donnellan@au1.ibm.com> wrote: > On 26/01/18 00:14, Frédéric Bonnard wrote: > > i2c.c fails to compile with gcc7 and -Werror=format-overflow used in > > Debian Unstable and Ubuntu 18.04 : > > > > i2c.c: In function ‘i2c_init’: > > i2c.c:211:15: error: ‘%s’ directive writing up to 255 bytes into a > > region of size 236 [-Werror=format-overflow=] > > > > We just make sure we never write more than what the destination can > > store. > > > > Signed-off-by: Frédéric Bonnard <frediz@linux.vnet.ibm.com> > > --- > > external/opal-prd/i2c.c | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/external/opal-prd/i2c.c b/external/opal-prd/i2c.c > > index ba4b3c85..dca303e4 100644 > > --- a/external/opal-prd/i2c.c > > +++ b/external/opal-prd/i2c.c > > @@ -234,7 +234,13 @@ void i2c_init(void) > > continue; > > > > /* Get bus name */ > > - sprintf(dpath, SYSFS "/class/i2c-dev/%s/name", devent->d_name); > > + if (snprintf(dpath, NAME_MAX, SYSFS "/class/i2c-dev/%s/name", > > + devent->d_name) < 0 ) { > > If the string is too long, snprintf() will truncate and return number of > bytes written, not a negative error code. indeed.. what was I thinking. > > + pr_log(LOG_ERR, "I2C: bus name longer than NAME_MAX : " > > Strictly speaking, the bus name doesn't have to be longer than NAME_MAX, > it's the entire path. > > I suspect that dpath should actually be of length PATH_MAX... That would make much more sense actually. Thanks for your help. F. > > Andrew > > > + SYSFS "/class/i2c-dev/%s/name", > > + devent->d_name); > > + return; > > + } > > f = fopen(dpath, "r"); > > if (!f) { > > pr_log(LOG_NOTICE, "I2C: Can't open %s: %m, skipping.", > > > > -- > Andrew Donnellan OzLabs, ADL Canberra > andrew.donnellan@au1.ibm.com IBM Australia Limited
diff --git a/external/opal-prd/i2c.c b/external/opal-prd/i2c.c index ba4b3c85..dca303e4 100644 --- a/external/opal-prd/i2c.c +++ b/external/opal-prd/i2c.c @@ -234,7 +234,13 @@ void i2c_init(void) continue; /* Get bus name */ - sprintf(dpath, SYSFS "/class/i2c-dev/%s/name", devent->d_name); + if (snprintf(dpath, NAME_MAX, SYSFS "/class/i2c-dev/%s/name", + devent->d_name) < 0 ) { + pr_log(LOG_ERR, "I2C: bus name longer than NAME_MAX : " + SYSFS "/class/i2c-dev/%s/name", + devent->d_name); + return; + } f = fopen(dpath, "r"); if (!f) { pr_log(LOG_NOTICE, "I2C: Can't open %s: %m, skipping.",
i2c.c fails to compile with gcc7 and -Werror=format-overflow used in Debian Unstable and Ubuntu 18.04 : i2c.c: In function ‘i2c_init’: i2c.c:211:15: error: ‘%s’ directive writing up to 255 bytes into a region of size 236 [-Werror=format-overflow=] We just make sure we never write more than what the destination can store. Signed-off-by: Frédéric Bonnard <frediz@linux.vnet.ibm.com> --- external/opal-prd/i2c.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)