lib/sysfs: add functions for SCSI host attributes

Signed-off-by: Karel Zak <kzak@redhat.com>

3 files changed, 66 insertions, 42 deletions

diff --git a/include/sysfs.h b/include/sysfs.h
index 10875d421..f0d33611e 100644
--- a/include/sysfs.h
+++ b/include/sysfs.h
@@ -75,5 +75,8 @@ extern int sysfs_devno_to_wholedisk(dev_t dev, char *diskname,
 
 extern int sysfs_scsi_get_hctl(struct sysfs_cxt *cxt, int *h,
 			       int *c, int *t, int *l);
+extern char *sysfs_scsi_host_strdup_attribute(struct sysfs_cxt *cxt,
+                const char *type, const char *attr);
+extern int sysfs_scsi_host_is(struct sysfs_cxt *cxt, const char *type);
 
 #endif /* UTIL_LINUX_SYSFS_H */
diff --git a/lib/sysfs.c b/lib/sysfs.c
index 4cb6284ca..d0c6c8944 100644
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -672,6 +672,58 @@ done:
 	return 0;
 }
 
+
+static char *sysfs_scsi_host_attribute_path(struct sysfs_cxt *cxt,
+		const char *type, char *buf, size_t bufsz, const char *attr)
+{
+	int len;
+	int host;
+
+	if (sysfs_scsi_get_hctl(cxt, &host, NULL, NULL, NULL))
+		return NULL;
+
+	if (attr)
+		len = snprintf(buf, bufsz, "/sys/class/%s_host/host%d/%s",
+				type, host, attr);
+	else
+		len = snprintf(buf, bufsz, "/sys/class/%s_host/host%d",
+				type, host);
+
+	return (len < 0 || (size_t) len + 1 > bufsz) ? NULL : buf;
+}
+
+char *sysfs_scsi_host_strdup_attribute(struct sysfs_cxt *cxt,
+		const char *type, const char *attr)
+{
+	char buf[1024];
+	int rc;
+	FILE *f;
+
+	if (!attr || !type ||
+	    !sysfs_scsi_host_attribute_path(cxt, type, buf, sizeof(buf), attr))
+		return NULL;
+
+	if (!(f = fopen(buf, "r")))
+                return NULL;
+
+	rc = fscanf(f, "%1023[^\n]", buf);
+	fclose(f);
+
+	return rc == 1 ? strdup(buf) : NULL;
+}
+
+int sysfs_scsi_host_is(struct sysfs_cxt *cxt, const char *type)
+{
+	char buf[PATH_MAX];
+	struct stat st;
+
+	if (!type || !sysfs_scsi_host_attribute_path(cxt, type,
+				buf, sizeof(buf), NULL))
+		return 0;
+
+	return stat(buf, &st) == 0 && S_ISDIR(st.st_mode);
+}
+
 #ifdef TEST_PROGRAM_SYSFS
 #include <errno.h>
 #include <err.h>
diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index c3803d826..104270418 100644
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -577,40 +577,6 @@ static char *get_type(struct blkdev_cxt *cxt)
 	return res;
 }
 
-static char *_sysfs_host_string(const char *type, int host, const char *attr)
-{
-	char path[PATH_MAX], tmp[64] = {0};
-	int fd, r;
-
-	if (snprintf(path, sizeof(path), "/sys/class/%s_host/host%d/%s",
-			type, host, attr) < 0)
-		return NULL;
-	if ((fd = open(path, O_RDONLY)) < 0)
-                return NULL;
-	r = read(fd, tmp, sizeof(tmp));
-	close(fd);
-
-	if (r <= 0)
-		return NULL;
-
-	return xstrdup(tmp);
-}
-
-static int _sysfs_host_exists(const char *type, int host)
-{
-	char buf[PATH_MAX];
-	struct stat st;
-
-	if (snprintf(buf, sizeof(buf), "/sys/class/%s_host/host%d",
-		     type, host) < 0)
-		return 0;
-
-	if (!stat(buf, &st) && S_ISDIR(st.st_mode))
-		return 1;
-
-	return 0;
-}
-
 static int _sysfs_scsi_attr_exists(const char *attr, int h, int c, int t, int l)
 {
 	char buf[PATH_MAX];
@@ -647,19 +613,21 @@ static int _sysfs_scsi_path_contains(const char *pattern, int h, int c, int t, i
 /* Thanks to lsscsi code for idea of detection logic used here */
 static char *get_transport(struct blkdev_cxt *cxt)
 {
+	struct sysfs_cxt *sysfs = &cxt->sysfs;
 	int host, channel, target, lun;
 	char *attr;
 
-	if (sysfs_scsi_get_hctl(&cxt->sysfs, &host, &channel, &target, &lun) != 0)
+	if (sysfs_scsi_get_hctl(sysfs, &host, &channel, &target, &lun) != 0)
 		return NULL;
 
 	/* SPI - Serial Peripheral Interface */
-	if (_sysfs_host_exists("spi", host))
+	if (sysfs_scsi_host_is(sysfs, "spi"))
 		return xstrdup("spi");
 
 	/* FC/FCoE - Fibre Channel / Fibre Channel over Ethernet */
-	if (_sysfs_host_exists("fc", host)) {
-		if (!(attr = _sysfs_host_string("fc", host, "symbolic_name")))
+	if (sysfs_scsi_host_is(sysfs, "fc")) {
+		attr = sysfs_scsi_host_strdup_attribute(sysfs, "fc", "symbolic_name");
+		if (!attr)
 			return NULL;
 		if (strstr(attr, " over "))
 			return xstrdup("fcoe");
@@ -667,7 +635,7 @@ static char *get_transport(struct blkdev_cxt *cxt)
 	}
 
 	/* SAS - Serial Attached SCSI */
-	if (_sysfs_host_exists("sas", host))
+	if (sysfs_scsi_host_is(sysfs, "sas"))
 		return xstrdup("sas");
 
 	if (_sysfs_scsi_attr_exists("sas_device", host, channel, target, lun))
@@ -678,7 +646,7 @@ static char *get_transport(struct blkdev_cxt *cxt)
 		return xstrdup("sbp");
 
 	/* iSCSI */
-	if (_sysfs_host_exists("iscsi", host))
+	if (sysfs_scsi_host_is(sysfs, "iscsi"))
 		return xstrdup("iscsi");
 
 	/* USB - Universal Serial Bus */
@@ -686,8 +654,9 @@ static char *get_transport(struct blkdev_cxt *cxt)
 		return xstrdup("usb");
 
 	/* ATA, SATA */
-	if (_sysfs_host_exists("scsi", host)) {
-		if (!(attr = _sysfs_host_string("scsi", host, "proc_name")))
+	if (sysfs_scsi_host_is(sysfs, "scsi")) {
+		attr = sysfs_scsi_host_strdup_attribute(sysfs, "scsi", "proc_name");
+		if (!attr)
 			return NULL;
 		if (!strncmp(attr, "ahci", 4) ||
 		    !strncmp(attr, "sata", 4))