Reduce dependency on libsysfs

Reduce libibverbs dependency on libsysfs by using local functions for
internal sysfs access.  libsysfs is still required because of the ABI,
which passes a struct sysfs_class_device * to low-level driver init
functions.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

8 files changed, 154 insertions, 66 deletions

diff --git a/ChangeLog b/ChangeLog
index 8acd8b5..d4abeae 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2006-04-11  Roland Dreier  <rdreier@cisco.com>
 
+	* src/device.c (ibv_get_device_guid), src/verbs.c (ibv_query_gid,
+	ibv_query_pkey), src/init.c (init_drivers, check_abi_version): Use
+	libibverbs functions instead of libsysfs functions to get to sysfs.
+
+	* src/sysfs.c (ibv_get_sysfs_path, ibv_read_sysfs_file): Add some
+	simple functions for accessing sysfs without using libsysfs.
+
 	* include/infiniband/sa-kern-abi.h: Deprecate struct
 	ib_kern_path_rec name; struct ibv_kern_path_rec is now preferred.
 
diff --git a/Makefile.am b/Makefile.am
index 171bcec..a3b575a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -15,7 +15,7 @@ else
 endif
 
 src_libibverbs_la_SOURCES = src/cmd.c src/device.c src/init.c src/marshall.c \
-			    src/memory.c src/verbs.c
+			    src/memory.c src/sysfs.c src/verbs.c
 src_libibverbs_la_LDFLAGS = -version-info 1 -export-dynamic \
     $(libibverbs_version_script)
 src_libibverbs_la_DEPENDENCIES = $(srcdir)/src/libibverbs.map
diff --git a/include/infiniband/driver.h b/include/infiniband/driver.h
index 8d2f6e4..6b01275 100644
--- a/include/infiniband/driver.h
+++ b/include/infiniband/driver.h
@@ -136,4 +136,12 @@ int ibv_cmd_destroy_ah(struct ibv_ah *ah);
 int ibv_cmd_attach_mcast(struct ibv_qp *qp, union ibv_gid *gid, uint16_t lid);
 int ibv_cmd_detach_mcast(struct ibv_qp *qp, union ibv_gid *gid, uint16_t lid);
 
+/*
+ * sysfs helper functions
+ */
+const char *ibv_get_sysfs_path(void);
+
+int ibv_read_sysfs_file(const char *dir, const char *file,
+			char *buf, size_t size);
+
 #endif /* INFINIBAND_DRIVER_H */
diff --git a/src/device.c b/src/device.c
index 1139c96..3ab6ceb 100644
--- a/src/device.c
+++ b/src/device.c
@@ -87,16 +87,16 @@ const char *ibv_get_device_name(struct ibv_device *device)
 
 uint64_t ibv_get_device_guid(struct ibv_device *device)
 {
-	struct sysfs_attribute *attr;
+	char attr[24];
 	uint64_t guid = 0;
 	uint16_t parts[4];
 	int i;
 
-	attr = sysfs_get_classdev_attr(device->ibdev, "node_guid");
-	if (!attr)
+	if (ibv_read_sysfs_file(device->ibdev->path, "node_guid",
+				attr, sizeof attr) < 0)
 		return 0;
 
-	if (sscanf(attr->value, "%hx:%hx:%hx:%hx",
+	if (sscanf(attr, "%hx:%hx:%hx:%hx",
 		   parts, parts + 1, parts + 2, parts + 3) != 4)
 		return 0;
 
diff --git a/src/init.c b/src/init.c
index a15d295..4b943b8 100644
--- a/src/init.c
+++ b/src/init.c
@@ -121,24 +121,21 @@ static void find_drivers(char *dir)
 static struct ibv_device *init_drivers(struct sysfs_class_device *verbs_dev)
 {
 	struct sysfs_class_device *ib_dev;
-	struct sysfs_attribute *attr;
 	struct ibv_driver *driver;
 	struct ibv_device *dev;
 	char ibdev_name[64];
 
-	attr = sysfs_get_classdev_attr(verbs_dev, "ibdev");
-	if (!attr) {
+	if (ibv_read_sysfs_file(verbs_dev->path, "ibdev",
+				ibdev_name, sizeof ibdev_name) < 0) {
 		fprintf(stderr, PFX "Warning: no ibdev class attr for %s\n",
 			verbs_dev->name);
 		return NULL;
 	}
 
-	sscanf(attr->value, "%63s", ibdev_name);
-
 	ib_dev = sysfs_open_class_device("infiniband", ibdev_name);
 	if (!ib_dev) {
 		fprintf(stderr, PFX "Warning: no infiniband class device %s for %s\n",
-			attr->value, verbs_dev->name);
+			ibdev_name, verbs_dev->name);
 		return NULL;
 	}
 
@@ -164,44 +161,34 @@ static struct ibv_device *init_drivers(struct sysfs_class_device *verbs_dev)
 
 static int check_abi_version(void)
 {
-	char path[256];
-	struct sysfs_attribute *attr;
-	int ret = -1;
+	const char *path;
+	char value[8];
 
-	if (sysfs_get_mnt_path(path, sizeof path)) {
+	path = ibv_get_sysfs_path();
+	if (!path) {
 		fprintf(stderr, PFX "Fatal: couldn't find sysfs mount.\n");
 		return -1;
 	}
 
-	strncat(path, "/class/infiniband_verbs/abi_version", sizeof path);
-
-	attr = sysfs_open_attribute(path);
-	if (!attr)
-		return -1;
-
-	if (sysfs_read_attribute(attr)) {
+	if (ibv_read_sysfs_file(path, "class/infiniband_verbs/abi_version",
+				value, sizeof value) < 0) {
 		fprintf(stderr, PFX "Fatal: couldn't read uverbs ABI version.\n");
-		goto out;
+		return -1;
 	}
 
-	abi_ver = strtol(attr->value, NULL, 10);
+	abi_ver = strtol(value, NULL, 10);
 
 	if (abi_ver < IB_USER_VERBS_MIN_ABI_VERSION ||
 	    abi_ver > IB_USER_VERBS_MAX_ABI_VERSION) {
 		fprintf(stderr, PFX "Fatal: kernel ABI version %d "
 			"doesn't match library version %d.\n",
 			abi_ver, IB_USER_VERBS_MAX_ABI_VERSION);
-		goto out;
+		return -1;
 	}
 
-	ret = 0;
-
-out:
-	sysfs_close_attribute(attr);
-	return ret;
+	return 0;
 }
 
-
 HIDDEN int ibverbs_init(struct ibv_device ***list)
 {
 	char *wr_path, *dir;
@@ -221,7 +208,7 @@ HIDDEN int ibverbs_init(struct ibv_device ***list)
 	find_drivers(default_path);
 
 	/*
-	 * Only follow the path passed in through the calling user's
+	 * Only follow use path passed in through the calling user's
 	 * environment if we're not running SUID.
 	 */
 	if (getuid() == geteuid()) {
diff --git a/src/libibverbs.map b/src/libibverbs.map
index 29eb220..fba7026 100644
--- a/src/libibverbs.map
+++ b/src/libibverbs.map
@@ -69,6 +69,9 @@ IBVERBS_1.0 {
 		ibv_copy_path_rec_to_kern;
 		ibv_rate_to_mult;
 		mult_to_ibv_rate;
+		ibv_get_sysfs_path;
+		ibv_read_sysfs_file;
+
 		ib_copy_qp_attr_from_kern;
 		ib_copy_path_rec_from_kern;
 		ib_copy_path_rec_to_kern;
diff --git a/src/sysfs.c b/src/sysfs.c
new file mode 100644
index 0000000..e97f0e8
--- /dev/null
+++ b/src/sysfs.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2006 Cisco Systems.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * $Id$
+ */
+
+#if HAVE_CONFIG_H
+#  include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "ibverbs.h"
+
+static char *sysfs_path;
+
+const char *ibv_get_sysfs_path(void)
+{
+	char *env = NULL;
+
+	if (sysfs_path)
+		return sysfs_path;
+
+	/*
+	 * Only follow use path passed in through the calling user's
+	 * environment if we're not running SUID.
+	 */
+	if (getuid() == geteuid())
+		env = getenv("SYSFS_PATH");
+
+	if (env) {
+		int len;
+
+		sysfs_path = strndup(env, 256);
+		len = strlen(sysfs_path);
+		while (len > 0 && sysfs_path[len - 1] == '/') {
+			--len;
+			sysfs_path[len] = '\0';
+		}
+	} else
+		sysfs_path = "/sys";
+
+	return sysfs_path;
+}
+
+int ibv_read_sysfs_file(const char *dir, const char *file,
+			char *buf, size_t size)
+{
+	char *path;
+	int fd;
+	int len;
+
+	asprintf(&path, "%s/%s", dir, file);
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	len = read(fd, buf, size);
+
+	close(fd);
+	free(path);
+
+	if (len > 0 && buf[len - 1] == '\n')
+		buf[--len] = '\0';
+
+	return len;
+}
diff --git a/src/verbs.c b/src/verbs.c
index 0397710..4f63763 100644
--- a/src/verbs.c
+++ b/src/verbs.c
@@ -92,63 +92,45 @@ int ibv_query_port(struct ibv_context *context, uint8_t port_num,
 int ibv_query_gid(struct ibv_context *context, uint8_t port_num,
 		  int index, union ibv_gid *gid)
 {
-	char *attr_name;
-	struct sysfs_attribute *attr;
+	char name[24];
+	char attr[41];
 	uint16_t val;
 	int i;
-	int ret = -1;
 
-	asprintf(&attr_name, "%s/ports/%d/gids/%d",
-		 context->device->ibdev->path, port_num, index);
+	snprintf(name, sizeof name, "ports/%d/gids/%d", port_num, index);
 
-	attr = sysfs_open_attribute(attr_name);
-	if (!attr)
+	if (ibv_read_sysfs_file(context->device->ibdev->path, name,
+				attr, sizeof attr) < 0)
 		return -1;
 
-	if (sysfs_read_attribute(attr))
-		goto out;
-
 	for (i = 0; i < 8; ++i) {
-		if (sscanf(attr->value + i * 5, "%hx", &val) != 1)
-			goto out;
+		if (sscanf(attr + i * 5, "%hx", &val) != 1)
+			return -1;
 		gid->raw[i * 2    ] = val >> 8;
 		gid->raw[i * 2 + 1] = val & 0xff;
 	}
 
-	ret = 0;
-
-out:
-	sysfs_close_attribute(attr);
-	return ret;
+	return 0;
 }
 
 int ibv_query_pkey(struct ibv_context *context, uint8_t port_num,
 		   int index, uint16_t *pkey)
 {
-	char *attr_name;
-	struct sysfs_attribute *attr;
+	char name[24];
+	char attr[8];
 	uint16_t val;
-	int ret = -1;
 
-	asprintf(&attr_name, "%s/ports/%d/pkeys/%d",
-		 context->device->ibdev->path, port_num, index);
+	snprintf(name, sizeof name, "ports/%d/pkeys/%d", port_num, index);
 
-	attr = sysfs_open_attribute(attr_name);
-	if (!attr)
+	if (ibv_read_sysfs_file(context->device->ibdev->path, name,
+				attr, sizeof attr) < 0)
 		return -1;
 
-	if (sysfs_read_attribute(attr))
-		goto out;
-
-	if (sscanf(attr->value, "%hx", &val) != 1)
-		goto out;
+	if (sscanf(attr, "%hx", &val) != 1)
+		return -1;
 
 	*pkey = htons(val);
-	ret = 0;
-
-out:
-	sysfs_close_attribute(attr);
-	return ret;
+	return 0;
 }
 
 struct ibv_pd *ibv_alloc_pd(struct ibv_context *context)