diff --git a/src/freebsd_pci.c b/src/freebsd_pci.c
index 3794328cd5ff0e3c0fae260f69d6e3b67ecb4240..709bfb6556fef6c43ee6eb823af40bc1b31f20dc 100644
--- a/src/freebsd_pci.c
+++ b/src/freebsd_pci.c
@@ -663,12 +663,14 @@ pci_system_freebsd_create( void )
 
     if ( ioctl( pcidev, PCIOCGETCONF, &pciconfio ) == -1) {
 	free( pci_sys );
+	pci_sys = NULL;
 	close( pcidev );
 	return errno;
     }
 
     if (pciconfio.status == PCI_GETCONF_ERROR ) {
 	free( pci_sys );
+	pci_sys = NULL;
 	close( pcidev );
 	return EINVAL;
     }
diff --git a/src/linux_devmem.h b/src/linux_devmem.h
index e69557fec95193ede53e68ab8086edc78f0e93a8..0ae54527e58dd82cc9d61ab66ad7951c8940c516 100644
--- a/src/linux_devmem.h
+++ b/src/linux_devmem.h
@@ -30,5 +30,10 @@
  * \author Ian Romanick <idr@us.ibm.com>
  */
 
+#ifndef LINUX_DEVMEM_H
+#define LINUX_DEVMEM_H
+
 extern int pci_device_linux_devmem_read_rom(struct pci_device *dev,
 					    void *buffer);
+
+#endif
diff --git a/src/linux_sysfs.c b/src/linux_sysfs.c
index d79404ec0df5bedcf80fe4f1ec1d16fe15fb8a56..1b4051b60c59b71bae52bc67b160b699ebf3bba9 100644
--- a/src/linux_sysfs.c
+++ b/src/linux_sysfs.c
@@ -981,7 +981,7 @@ pci_device_linux_sysfs_map_legacy(struct pci_device *dev, pciaddr_t base,
     int ret=0;
 
     if (map_flags & PCI_DEV_MAP_FLAG_WRITABLE) {
-	flags = O_RDWR; /* O_RDWR != O_WRONLY | O_RDONLY */;
+	flags = O_RDWR; /* O_RDWR != O_WRONLY | O_RDONLY */
 	prot |= PROT_WRITE;
     }
 
diff --git a/src/netbsd_pci.c b/src/netbsd_pci.c
index 1f3bceacad9f5c47d0b405f9d45bcd0880067aec..b6a5ccdec0a6428d76dc79f12e7a2af0525267cb 100644
--- a/src/netbsd_pci.c
+++ b/src/netbsd_pci.c
@@ -942,6 +942,7 @@ pci_system_netbsd_create(void)
 		for (i = 0; i < nbuses; i++)
 			close(buses[i].fd);
 		free(pci_sys);
+		pci_sys = NULL;
 		return ENOMEM;
 	}
 
diff --git a/src/pci_tools.h b/src/pci_tools.h
index 37668902b03f59cbea3fd42d1e6bc48cd846b2d6..47b121fd4232d824558a56a8031d1d3139b88498 100644
--- a/src/pci_tools.h
+++ b/src/pci_tools.h
@@ -165,7 +165,7 @@ typedef struct pcitool_intr_get {
 #define	PCITOOL_IGET_SIZE(num_devs) \
 	(sizeof (pcitool_intr_get_t) - \
 	sizeof (pcitool_intr_dev_t) + \
-	(num_devs * sizeof (pcitool_intr_dev_t)))
+	((num_devs) * sizeof (pcitool_intr_dev_t)))
 
 /*
  * Size and endian fields for acc_attr bitmask.
@@ -175,12 +175,12 @@ typedef struct pcitool_intr_get {
 #define	PCITOOL_ACC_ATTR_SIZE_2		0x1
 #define	PCITOOL_ACC_ATTR_SIZE_4		0x2
 #define	PCITOOL_ACC_ATTR_SIZE_8		0x3
-#define	PCITOOL_ACC_ATTR_SIZE(x)	(1 << (x & PCITOOL_ACC_ATTR_SIZE_MASK))
+#define	PCITOOL_ACC_ATTR_SIZE(x)	(1 << ((x) & PCITOOL_ACC_ATTR_SIZE_MASK))
 
 #define	PCITOOL_ACC_ATTR_ENDN_MASK	0x100
 #define	PCITOOL_ACC_ATTR_ENDN_LTL	0x0
 #define	PCITOOL_ACC_ATTR_ENDN_BIG	0x100
-#define	PCITOOL_ACC_IS_BIG_ENDIAN(x)	(x & PCITOOL_ACC_ATTR_ENDN_BIG)
+#define	PCITOOL_ACC_IS_BIG_ENDIAN(x)	((x) & PCITOOL_ACC_ATTR_ENDN_BIG)
 
 /*
  * Data structure to read and write to pci device registers.