| Message ID | 1498650385-17478-1-git-send-email-thuth@redhat.com |
|---|---|
| State | Accepted |
| Headers | show |
On 28/06/17 21:46, Thomas Huth wrote: > It's theoretically possible to load a file to address 0, too, so > we should use a different marker than NULL to check for a valid > buffer. Thanks, applied. Out of curiosity - what brought this up? :) > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > lib/libnet/tftp.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/lib/libnet/tftp.c b/lib/libnet/tftp.c > index d0c2f13..ab63578 100644 > --- a/lib/libnet/tftp.c > +++ b/lib/libnet/tftp.c > @@ -26,6 +26,7 @@ > > #define MAX_BLOCKSIZE 1428 > #define BUFFER_LEN 256 > +#define INVALID_BUFFER ((void *)-1L) > > #define ENOTFOUND 1 > #define EACCESS 2 > @@ -45,7 +46,7 @@ > > /* Local variables */ > static unsigned char packet[BUFFER_LEN]; > -static unsigned char *buffer = NULL; > +static unsigned char *buffer = INVALID_BUFFER; > static unsigned short block; > static unsigned short blocksize; > static char blocksize_str[6]; /* Blocksize string for read request */ > @@ -337,7 +338,7 @@ int32_t handle_tftp(int fd, uint8_t *pkt, int32_t packetsize) > struct tftphdr *tftp; > > /* buffer is only set if we are handling TFTP */ > - if (buffer == NULL ) > + if (buffer == INVALID_BUFFER) > return 0; > > #ifndef __DEBUG__ > @@ -536,7 +537,7 @@ int tftp(filename_ip_t * _fn_ip, unsigned char *_buffer, int _len, > printf(" Receiving data: "); > print_progress(-1, 0); > > - // Setting buffer to a non-zero address enabled handling of received TFTP packets. > + /* Set buffer to a valid address, enables handling of received packets */ > buffer = _buffer; > > set_timer(TICKS_SEC); > @@ -579,8 +580,8 @@ int tftp(filename_ip_t * _fn_ip, unsigned char *_buffer, int _len, > } > } > > - // Setting buffer to NULL disables handling of received TFTP packets. > - buffer = NULL; > + /* Setting buffer invalid to disable handling of received packets */ > + buffer = INVALID_BUFFER; > > if (tftp_errno) > return tftp_errno; >
On 30.06.2017 08:06, Alexey Kardashevskiy wrote: > On 28/06/17 21:46, Thomas Huth wrote: >> It's theoretically possible to load a file to address 0, too, so >> we should use a different marker than NULL to check for a valid >> buffer. > > Thanks, applied. Thanks a lot! > Out of curiosity - what brought this up? :) I'm currently trying to re-use the libnet for network booting a s390x guest, and kernels get loaded to address 0 there: https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg05911.html Thomas
diff --git a/lib/libnet/tftp.c b/lib/libnet/tftp.c index d0c2f13..ab63578 100644 --- a/lib/libnet/tftp.c +++ b/lib/libnet/tftp.c @@ -26,6 +26,7 @@ #define MAX_BLOCKSIZE 1428 #define BUFFER_LEN 256 +#define INVALID_BUFFER ((void *)-1L) #define ENOTFOUND 1 #define EACCESS 2 @@ -45,7 +46,7 @@ /* Local variables */ static unsigned char packet[BUFFER_LEN]; -static unsigned char *buffer = NULL; +static unsigned char *buffer = INVALID_BUFFER; static unsigned short block; static unsigned short blocksize; static char blocksize_str[6]; /* Blocksize string for read request */ @@ -337,7 +338,7 @@ int32_t handle_tftp(int fd, uint8_t *pkt, int32_t packetsize) struct tftphdr *tftp; /* buffer is only set if we are handling TFTP */ - if (buffer == NULL ) + if (buffer == INVALID_BUFFER) return 0; #ifndef __DEBUG__ @@ -536,7 +537,7 @@ int tftp(filename_ip_t * _fn_ip, unsigned char *_buffer, int _len, printf(" Receiving data: "); print_progress(-1, 0); - // Setting buffer to a non-zero address enabled handling of received TFTP packets. + /* Set buffer to a valid address, enables handling of received packets */ buffer = _buffer; set_timer(TICKS_SEC); @@ -579,8 +580,8 @@ int tftp(filename_ip_t * _fn_ip, unsigned char *_buffer, int _len, } } - // Setting buffer to NULL disables handling of received TFTP packets. - buffer = NULL; + /* Setting buffer invalid to disable handling of received packets */ + buffer = INVALID_BUFFER; if (tftp_errno) return tftp_errno;
It's theoretically possible to load a file to address 0, too, so we should use a different marker than NULL to check for a valid buffer. Signed-off-by: Thomas Huth <thuth@redhat.com> --- lib/libnet/tftp.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)