i2cdump: bail-out if block read fails

We should bail-out if i2c_smbus_read_block_data() or
i2c_smbus_read_i2c_block_data() return 0 or less. Add the missing check
for the former and fix the existing for the latter.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/miscutils/i2c_tools.c b/miscutils/i2c_tools.c
index 6d221e9fc..7be489036 100644
--- a/miscutils/i2c_tools.c
+++ b/miscutils/i2c_tools.c
@@ -724,16 +724,16 @@ static int read_block_data(int buf_fd, int mode, int *block)
         int res, blen = 0, tmp, i;
 
         if (mode == I2C_SMBUS_BLOCK_DATA) {
-                res = i2c_smbus_read_block_data(buf_fd, 0, cblock);
-                blen = res;
+                blen = i2c_smbus_read_block_data(buf_fd, 0, cblock);
+                if (blen <= 0)
+                        goto fail;
         } else {
                 for (res = 0; res < I2CDUMP_NUM_REGS; res += tmp) {
                         tmp = i2c_smbus_read_i2c_block_data(
                                         buf_fd, res, I2C_SMBUS_BLOCK_MAX,
                                         cblock + res);
-                        if (tmp < 0) {
-                                bb_error_msg_and_die("block read failed");
-                        }
+                        if (tmp <= 0)
+                                goto fail;
                 }
 
                 if (res >= I2CDUMP_NUM_REGS)
@@ -748,6 +748,9 @@ static int read_block_data(int buf_fd, int mode, int *block)
         }
 
         return blen;
+
+ fail:
+        bb_error_msg_and_die("block read failed");
 }
 
 /* Dump all but word data. */