[libcheckers] add the directio checker

Created by Hannes Reinecke, Suse, mainly for DASD devices.

4 files changed, 176 insertions, 1 deletions

diff --git a/libcheckers/Makefile b/libcheckers/Makefile
index c737da1..b3e7231 100644
--- a/libcheckers/Makefile
+++ b/libcheckers/Makefile
@@ -6,7 +6,7 @@ BUILD = glibc
 
 include ../Makefile.inc
 
-OBJS = readsector0.o tur.o selector.o emc_clariion.o hp_sw.o
+OBJS = readsector0.o tur.o selector.o directio.o emc_clariion.o hp_sw.o
 
 all: $(BUILD)
 
diff --git a/libcheckers/checkers.h b/libcheckers/checkers.h
index 363147f..92ecfe5 100644
--- a/libcheckers/checkers.h
+++ b/libcheckers/checkers.h
@@ -9,6 +9,7 @@ enum checkers {
 	CHECKER_UNDEF,
 	TUR,
 	READSECTOR0,
+	DIRECTIO,
 	EMC_CLARIION,
 	HP_SW
 };
@@ -21,6 +22,7 @@ void *get_checker_addr (int);
 int get_checker_name (char *, int);
 
 int emc_clariion (int fd, char * msg, void ** ctxt);
+int directio (int fd, char * msg, void ** ctxt);
 int readsector0 (int fd, char * msg, void ** ctxt);
 int tur (int fd, char * msg, void ** ctxt);
 int hp_sw (int fd, char * msg, void ** ctxt);
diff --git a/libcheckers/directio.c b/libcheckers/directio.c
new file mode 100644
index 0000000..6f52494
--- /dev/null
+++ b/libcheckers/directio.c
@@ -0,0 +1,165 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+#include <errno.h>
+
+#include "path_state.h"
+#include "checkers.h"
+
+#define MSG_DIRECTIO_UNKNOWN	"directio checker is not available"
+#define MSG_DIRECTIO_UP		"directio checker reports path is up"
+#define MSG_DIRECTIO_DOWN	"directio checker reports path is down"
+
+struct readsector0_checker_context {
+	void * dummy;
+};
+
+static int
+direct_read (int fd, unsigned char * buff, int size)
+{
+	long flags;
+	int reset_flags = 0;
+	int res, retval;
+
+	flags = fcntl(fd,F_GETFL);
+
+	if (flags < 0) {
+		return PATH_UNCHECKED;
+	}
+
+	if (!(flags & O_DIRECT)) {
+		flags |= O_DIRECT;
+		if (fcntl(fd,F_SETFL,flags) < 0) {
+			return PATH_UNCHECKED;
+		}
+		reset_flags = 1;
+	}
+
+	while ( (res = read(fd,buff,size)) < 0 && errno == EINTR );
+	if (res < 0) {
+		if (errno == EINVAL) {
+			/* O_DIRECT is not available */
+			retval = PATH_UNCHECKED;
+		} else if (errno == ENOMEM) {
+			retval = PATH_UP;
+		} else {
+			retval = PATH_DOWN;
+		}
+	} else {
+		retval = PATH_UP;
+	}
+	
+	if (reset_flags) {
+		flags &= ~O_DIRECT;
+		/* No point in checking for errors */
+		fcntl(fd,F_SETFL,flags);
+	}
+
+	return retval;
+}
+
+extern int
+directio (int fd, char *msg, void **context)
+{
+	unsigned char *buf, *ptr;
+	struct readsector0_checker_context * ctxt = NULL;
+	unsigned long pgsize, numsect;
+	int ret, blksize;
+
+	pgsize = getpagesize();
+	
+	/*
+	 * caller passed in a context : use its address
+	 */
+	if (context)
+		ctxt = (struct readsector0_checker_context *) (*context);
+
+	/*
+	 * passed in context is uninitialized or volatile context :
+	 * initialize it
+	 */
+	if (!ctxt) {
+		ctxt = malloc(sizeof(struct readsector0_checker_context));
+		memset(ctxt, 0, sizeof(struct readsector0_checker_context));
+
+		if (!ctxt) {
+			MSG("cannot allocate context");
+			return -1;
+		}
+		if (context)
+			*context = ctxt;
+	}
+	if (fd <= 0) {
+		MSG("no usable fd");
+		ret = -1;
+		goto out;
+	}
+	
+	if (ioctl(fd, BLKGETSIZE, &numsect) < 0) {
+		MSG("cannot get number of sectors, set default");
+		numsect = 0;
+	}
+
+	if (ioctl(fd, BLKBSZGET, &blksize) < 0) {
+		MSG("cannot get blocksize, set default");
+		blksize = 512;
+	}
+
+	if (blksize > 4096) {
+		/*
+		 * Sanity check for DASD; BSZGET is broken
+		 */
+		blksize = 4096;
+	}
+
+	if (!blksize) {
+		/*
+		 * Blocksize is 0, assume we can't write
+		 * to this device.
+		 */
+		MSG(MSG_DIRECTIO_DOWN);
+		ret = PATH_DOWN;
+		goto out;
+	}
+
+	buf = (unsigned char *)malloc(blksize + pgsize);
+	if (!buf){
+		goto out;
+	}
+	ptr = (unsigned char *)(((unsigned long)buf + pgsize - 1) &
+				(~(pgsize - 1))); 
+	ret = direct_read(fd, ptr, blksize);
+
+	switch (ret)
+	{
+	case PATH_UNCHECKED:
+		MSG(MSG_DIRECTIO_UNKNOWN);
+		break;
+	case PATH_DOWN:
+		MSG(MSG_DIRECTIO_DOWN);
+		break;
+	case PATH_UP:
+		MSG(MSG_DIRECTIO_UP);
+		break;
+	default:
+		break;
+	}
+	free(buf);
+
+out:
+	/*
+	 * caller told us he doesn't want to keep the context :
+	 * free it
+	 */
+	if (!context)
+		free(ctxt);
+
+	return ret;
+}
diff --git a/libcheckers/selector.c b/libcheckers/selector.c
index 306b198..43f88f0 100644
--- a/libcheckers/selector.c
+++ b/libcheckers/selector.c
@@ -10,6 +10,8 @@ get_checker_id (char * str)
 		return TUR;
 	if (0 == strncmp(str, "readsector0", 11))
 		return READSECTOR0;
+ 	if (0 == strncmp(str, "directio", 8))
+		return DIRECTIO;
  	if (0 == strncmp(str, "emc_clariion", 12))
 		return EMC_CLARIION;
  	if (0 == strncmp(str, "hp_sw", 5))
@@ -29,6 +31,9 @@ get_checker_addr (int id)
 	case READSECTOR0:
 		checker = &readsector0;
 		break;
+	case DIRECTIO:
+		checker = &directio;
+		break;
 	case EMC_CLARIION:
 		checker = &emc_clariion;
 		break;
@@ -54,6 +59,9 @@ get_checker_name (char * str, int id)
 	case READSECTOR0:
 		s = "readsector0";
 		break;
+	case DIRECTIO:
+		s = "directio";
+		break;
 	case EMC_CLARIION:
 		s = "emc_clariion";
 		break;