[openib-general] [PATCH/RFC] libibverbs: Improve driver loading
Roland Dreier
rdreier at cisco.com
Mon Nov 27 12:43:12 PST 2006
OK, at last here is a patch that implements the improvements to
libibverbs driver loading that we discussed back in October.
With this patch, instead of trying all the .so files in the
$(libdir)/infiniband directory as libibverbs 1.0 does, libibverbs
instead builds a list of drivers to load and dlopen() exactly that
list of libraries. It uses relative paths rather than absolute paths,
so the linker uses the normal search path to find driver libraries.
(To get a list of drivers, libibverbs parses all the config files it
finds in $(sysconfdir)/libibverbs.d and also looks at the environment
variables RDMAV_DRIVERS and IBV_DRIVERS)
Then, instead of calling a specific entry point in the driver,
libibverbs assumes the driver will call ibv_register_driver() from an
__attribute__((constructor)) function.
This has a number of benefits:
- multiple drivers can be linked statically into an executable
- LD_LIBRARY_PATH can be used to manage which drivers to load
- different versions of the driver can be selected automagically at
runtime (eg i686/cmov on i386 distros)
I will post a libmthca patch to illustrate how driver libraries need
to change to work with this new libibverbs method.
---
Makefile.am | 2 +-
README | 2 +-
include/infiniband/driver.h | 19 +-
src/ibverbs.h | 5 -
src/init.c | 486 ++++++++++++++++++++++++++++++-------------
src/libibverbs.map | 1 +
6 files changed, 347 insertions(+), 168 deletions(-)
diff --git a/Makefile.am b/Makefile.am
index 391c522..35f4468 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -4,7 +4,7 @@ lib_LTLIBRARIES = src/libibverbs.la
AM_CFLAGS = -g -Wall -D_GNU_SOURCE
-src_libibverbs_la_CFLAGS = -g -Wall -D_GNU_SOURCE -DDRIVER_PATH=\"$(libdir)/infiniband\"
+src_libibverbs_la_CFLAGS = $(AM_CFLAGS) -DIBV_CONFIG_DIR=\"$(sysconfdir)/libibverbs.d\"
libibverbs_version_script = @LIBIBVERBS_VERSION_SCRIPT@
diff --git a/README b/README
index 6190895..634fc3b 100644
--- a/README
+++ b/README
@@ -80,7 +80,7 @@ uninitialized" warnings. This code adds
critical performance path, so it is disabled by default. The intent
is that production users can use a "normal" build of libibverbs and
developers can use the "valgrind debug" build by simply switching
-their LD_LIBRARY_PATH and/or OPENIB_DRIVER_PATH environment variables.
+their LD_LIBRARY_PATH environment variables.
Libibverbs needs some header files from Valgrind in order to compile
this support; it is important to use the header files from the same
diff --git a/include/infiniband/driver.h b/include/infiniband/driver.h
index f759d52..8e2418c 100644
--- a/include/infiniband/driver.h
+++ b/include/infiniband/driver.h
@@ -47,21 +47,16 @@ # define END_C_DECLS
#endif /* __cplusplus */
/*
- * Device-specific drivers should declare their device init function
- * as below (the name must be "openib_driver_init"):
- *
- * struct ibv_device *ibv_driver_init(const char *uverbs_sys_path,
- * int abi_version);
- *
- * libibverbs will call each driver's ibv_driver_init() function once
- * for each InfiniBand device. If the device is one that the driver
- * can support, it should return a struct ibv_device * with the ops
- * member filled in. If the driver does not support the device, it
- * should return NULL from openib_driver_init().
+ * Extension that low-level drivers should add to their .so filename
+ * (probably via libtool "-release" option). For example a low-level
+ * driver named "libfoo" should build a plug-in named "libfoo-rdmav2.so".
*/
+#define IBV_DEVICE_LIBRARY_EXTENSION rdmav2
-typedef struct ibv_device *(*ibv_driver_init_func)(const char *, int);
+typedef struct ibv_device *(*ibv_driver_init_func)(const char *uverbs_sys_path,
+ int abi_version);
+void ibv_register_driver(const char *name, ibv_driver_init_func init_func);
int ibv_cmd_get_context(struct ibv_context *context, struct ibv_get_context *cmd,
size_t cmd_size, struct ibv_get_context_resp *resp,
size_t resp_size);
diff --git a/src/ibverbs.h b/src/ibverbs.h
index 4c6c07e..14330f8 100644
--- a/src/ibverbs.h
+++ b/src/ibverbs.h
@@ -58,11 +58,6 @@ #define FINI __attribute__((destructor)
#define PFX "libibverbs: "
-struct ibv_driver {
- ibv_driver_init_func init_func;
- struct ibv_driver *next;
-};
-
struct ibv_abi_compat_v2 {
struct ibv_comp_channel channel;
pthread_mutex_t in_use;
diff --git a/src/init.c b/src/init.c
index fe70852..0ced806 100644
--- a/src/init.c
+++ b/src/init.c
@@ -46,150 +46,312 @@ #include <dirent.h>
#include "ibverbs.h"
-#ifndef OPENIB_DRIVER_PATH_ENV
-# define OPENIB_DRIVER_PATH_ENV "OPENIB_DRIVER_PATH"
-#endif
-
HIDDEN int abi_ver;
-static const char default_path[] = DRIVER_PATH;
-static const char *user_path;
-
-static struct ibv_driver *driver_list;
-
-static void load_driver(char *so_path)
+struct ibv_sysfs_dev {
+ char sysfs_name[IBV_SYSFS_NAME_MAX];
+ char ibdev_name[IBV_SYSFS_NAME_MAX];
+ char sysfs_path[IBV_SYSFS_PATH_MAX];
+ char ibdev_path[IBV_SYSFS_PATH_MAX];
+ struct ibv_sysfs_dev *next;
+ int abi_ver;
+ int have_driver;
+};
+
+struct ibv_driver_name {
+ char *name;
+ struct ibv_driver_name *next;
+};
+
+struct ibv_driver {
+ const char *name;
+ ibv_driver_init_func init_func;
+ struct ibv_driver *next;
+};
+
+static struct ibv_sysfs_dev *sysfs_dev_list;
+static struct ibv_driver_name *driver_name_list;
+static struct ibv_driver *head_driver, *tail_driver;
+
+static void find_sysfs_devs(void)
{
- void *dlhandle;
- ibv_driver_init_func init_func;
- struct ibv_driver *driver;
+ char class_path[IBV_SYSFS_PATH_MAX];
+ DIR *class_dir;
+ struct dirent *dent;
+ struct ibv_sysfs_dev *sysfs_dev;
+ char value[8];
- dlhandle = dlopen(so_path, RTLD_NOW);
- if (!dlhandle) {
- fprintf(stderr, PFX "Warning: couldn't load driver %s: %s\n",
- so_path, dlerror());
+ snprintf(class_path, sizeof class_path, "%s/class/infiniband_verbs",
+ ibv_get_sysfs_path());
+
+ class_dir = opendir(class_path);
+ if (!class_dir) {
+ fprintf(stderr, PFX "Fatal: couldn't open sysfs class "
+ "directory '%s'.\n", class_path);
return;
}
- dlerror();
- init_func = dlsym(dlhandle, "ibv_driver_init");
- if (dlerror() != NULL || !init_func) {
- dlclose(dlhandle);
- return;
+ while ((dent = readdir(class_dir))) {
+ if (dent->d_name[0] == '.' || dent->d_type == DT_REG)
+ continue;
+
+ sysfs_dev = malloc(sizeof *sysfs_dev);
+ if (!sysfs_dev) {
+ fprintf(stderr, PFX "Warning: couldn't allocate sysfs dev "
+ "for '%s'.\n", dent->d_name);
+ continue;
+ }
+
+ snprintf(sysfs_dev->sysfs_name, sizeof sysfs_dev->sysfs_name,
+ "%s", dent->d_name);
+ snprintf(sysfs_dev->sysfs_path, sizeof sysfs_dev->sysfs_path,
+ "%s/%s", class_path, dent->d_name);
+
+ if (ibv_read_sysfs_file(sysfs_dev->sysfs_path, "ibdev",
+ sysfs_dev->ibdev_name,
+ sizeof sysfs_dev->ibdev_name) < 0) {
+ fprintf(stderr, PFX "Warning: no ibdev class attr for '%s'.\n",
+ dent->d_name);
+ free(sysfs_dev);
+ continue;
+ }
+
+ snprintf(sysfs_dev->ibdev_path, sizeof sysfs_dev->ibdev_path,
+ "%s/class/infiniband/%s", ibv_get_sysfs_path(),
+ sysfs_dev->ibdev_name);
+
+ sysfs_dev->next = NULL;
+ sysfs_dev->have_driver = 0;
+ if (ibv_read_sysfs_file(sysfs_dev->sysfs_path, "abi_version",
+ value, sizeof value) > 0)
+ sysfs_dev->abi_ver = strtol(value, NULL, 10);
+ else
+ sysfs_dev->abi_ver = 0;
+
+ sysfs_dev_list = sysfs_dev;
}
+ closedir(class_dir);
+}
+
+void ibv_register_driver(const char *name, ibv_driver_init_func init_func)
+{
+ struct ibv_driver *driver;
+
driver = malloc(sizeof *driver);
if (!driver) {
- fprintf(stderr, PFX "Fatal: couldn't allocate driver for %s\n", so_path);
- dlclose(dlhandle);
+ fprintf(stderr, PFX "Warning: couldn't allocate driver for %s\n", name);
return;
}
+ driver->name = name;
driver->init_func = init_func;
- driver->next = driver_list;
- driver_list = driver;
+ driver->next = NULL;
+
+ if (tail_driver)
+ tail_driver->next = driver;
+ else
+ head_driver = driver;
+ tail_driver = driver;
}
-static void find_drivers(const char *dir)
+static void load_driver(const char *name)
{
- size_t len = strlen(dir);
- glob_t so_glob;
- char *pat;
- int ret;
- int i;
+ char *so_name;
+ void *dlhandle;
+
+#define __IBV_QUOTE(x) #x
+#define IBV_QUOTE(x) __IBV_QUOTE(x)
- if (!len)
+ if (asprintf(&so_name,
+ "lib%s-" IBV_QUOTE(IBV_DEVICE_LIBRARY_EXTENSION) ".so",
+ name) < 0) {
+ fprintf(stderr, PFX "Warning: couldn't load driver '%s'.\n",
+ name);
return;
+ }
+
+ dlhandle = dlopen(so_name, RTLD_NOW);
+ if (!dlhandle) {
+ fprintf(stderr, PFX "Warning: couldn't load driver '%s': %s\n",
+ name, dlerror());
+ goto out;
+ }
- while (len && dir[len - 1] == '/')
- --len;
+out:
+ free(so_name);
+}
- asprintf(&pat, "%.*s/*.so", (int) len, dir);
+static void load_drivers(void)
+{
+ struct ibv_driver_name *name, *next_name;
+ const char *env;
+ char *list, *env_name;
+
+ for (name = driver_name_list, next_name = name->next;
+ name;
+ name = next_name, next_name = name ? name->next : NULL) {
+ load_driver(name->name);
+ free(name->name);
+ free(name);
+ }
- ret = glob(pat, 0, NULL, &so_glob);
- free(pat);
+ env = getenv("IBV_DRIVERS");
+ if (env) {
+ list = strdupa(env);
+ while ((env_name = strsep(&list, ":;")))
+ load_driver(env_name);
+ }
- if (ret) {
- if (ret != GLOB_NOMATCH)
- fprintf(stderr, PFX "Warning: couldn't search %s\n", pat);
+ env = getenv("RDMAV_DRIVERS");
+ if (env) {
+ list = strdupa(env);
+ while ((env_name = strsep(&list, ":;")))
+ load_driver(env_name);
+ }
+}
+
+static void read_config_file(const char *dir, const char *name)
+{
+ char *path;
+ FILE *conf;
+ char *line = NULL;
+ char *config;
+ char *field;
+ size_t buflen = 0;
+ ssize_t len;
+
+ if (asprintf(&path, "%s/%s", dir, name) < 0) {
+ fprintf(stderr, PFX "Warning: couldn't read config file %s/%s.\n",
+ dir, name);
return;
}
- for (i = 0; i < so_glob.gl_pathc; ++i)
- load_driver(so_glob.gl_pathv[i]);
+ conf = fopen(path, "r");
+ if (!conf) {
+ fprintf(stderr, PFX "Warning: couldn't read config file %s.\n",
+ path);
+ goto out;
+ }
+
+ while ((len = getline(&line, &buflen, conf)) != -1) {
+ config = line + strspn(line, "\t ");
+ if (config[0] == '\n' || config[0] == '#')
+ continue;
+
+ field = strsep(&config, "\n\t ");
+
+ if (strcmp(field, "driver") == 0) {
+ struct ibv_driver_name *driver_name;
+
+ config += strspn(config, "\t ");
+ field = strsep(&config, "\n\t ");
+
+ driver_name = malloc(sizeof *driver_name);
+ if (!driver_name) {
+ fprintf(stderr, PFX "Warning: couldn't allocate "
+ "driver name '%s'.\n", field);
+ continue;
+ }
+
+ driver_name->name = strdup(field);
+ if (!driver_name->name) {
+ fprintf(stderr, PFX "Warning: couldn't allocate "
+ "driver name '%s'.\n", field);
+ free(driver_name);
+ continue;
+ }
+
+ driver_name->next = driver_name_list;
+ driver_name_list = driver_name;
+ } else
+ fprintf(stderr, PFX "Warning: ignoring bad config directive "
+ "'%s' in file '%s'.\n", field, path);
+ }
- globfree(&so_glob);
+ if (line)
+ free(line);
+ fclose(conf);
+
+out:
+ free(path);
}
-static struct ibv_device *init_drivers(const char *class_path,
- const char *dev_name)
+static void read_config(void)
{
- struct ibv_driver *driver;
- struct ibv_device *dev;
- int abi_ver = 0;
- char sys_path[IBV_SYSFS_PATH_MAX];
- char ibdev_name[IBV_SYSFS_NAME_MAX];
- char ibdev_path[IBV_SYSFS_PATH_MAX];
- char value[8];
- enum ibv_node_type node_type;
+ DIR *conf_dir;
+ struct dirent *dent;
- snprintf(sys_path, sizeof sys_path, "%s/%s",
- class_path, dev_name);
+ conf_dir = opendir(IBV_CONFIG_DIR);
+ if (!conf_dir) {
+ fprintf(stderr, PFX "Warning: couldn't open config directory '%s'.\n",
+ IBV_CONFIG_DIR);
+ return;
+ }
- if (ibv_read_sysfs_file(sys_path, "abi_version", value, sizeof value) > 0)
- abi_ver = strtol(value, NULL, 10);
+ while ((dent = readdir(conf_dir))) {
+ if (dent->d_type != DT_REG)
+ continue;
- if (ibv_read_sysfs_file(sys_path, "ibdev", ibdev_name, sizeof ibdev_name) < 0) {
- fprintf(stderr, PFX "Warning: no ibdev class attr for %s\n",
- sys_path);
- return NULL;
+ read_config_file(IBV_CONFIG_DIR, dent->d_name);
}
- snprintf(ibdev_path, IBV_SYSFS_PATH_MAX, "%s/class/infiniband/%s",
- ibv_get_sysfs_path(), ibdev_name);
+ closedir(conf_dir);
+}
+
+static struct ibv_device *try_driver(struct ibv_driver *driver,
+ struct ibv_sysfs_dev *sysfs_dev)
+{
+ struct ibv_device *dev;
+ char value[8];
+ enum ibv_node_type node_type;
- if (ibv_read_sysfs_file(ibdev_path, "node_type", value, sizeof value) < 0) {
- fprintf(stderr, PFX "Warning: no node_type attr for %s\n",
- ibdev_path);
+ dev = driver->init_func(sysfs_dev->sysfs_path, sysfs_dev->abi_ver);
+ if (!dev)
return NULL;
+
+ if (ibv_read_sysfs_file(sysfs_dev->ibdev_path, "node_type", value, sizeof value) < 0) {
+ fprintf(stderr, PFX "Warning: no node_type attr under %s.\n",
+ sysfs_dev->ibdev_path);
+ node_type = IBV_NODE_UNKNOWN;
+ } else {
+ node_type = strtol(value, NULL, 10);
+ if (node_type < IBV_NODE_CA || node_type > IBV_NODE_RNIC)
+ node_type = IBV_NODE_UNKNOWN;
}
- node_type = strtol(value, NULL, 10);
- if (node_type < IBV_NODE_CA || node_type > IBV_NODE_RNIC)
- node_type = IBV_NODE_UNKNOWN;
- for (driver = driver_list; driver; driver = driver->next) {
- dev = driver->init_func(sys_path, abi_ver);
- if (!dev)
- continue;
+ switch (node_type) {
+ case IBV_NODE_CA:
+ case IBV_NODE_SWITCH:
+ case IBV_NODE_ROUTER:
+ dev->transport_type = IBV_TRANSPORT_IB;
+ break;
+ case IBV_NODE_RNIC:
+ dev->transport_type = IBV_TRANSPORT_IWARP;
+ break;
+ default:
+ dev->transport_type = IBV_TRANSPORT_UNKNOWN;
+ break;
+ }
- dev->node_type = node_type;
-
- switch (node_type) {
- case IBV_NODE_CA:
- case IBV_NODE_SWITCH:
- case IBV_NODE_ROUTER:
- dev->transport_type = IBV_TRANSPORT_IB;
- break;
- case IBV_NODE_RNIC:
- dev->transport_type = IBV_TRANSPORT_IWARP;
- break;
- default:
- dev->transport_type = IBV_TRANSPORT_UNKNOWN;
- break;
- }
+ strcpy(dev->dev_name, sysfs_dev->sysfs_name);
+ strcpy(dev->dev_path, sysfs_dev->sysfs_path);
+ strcpy(dev->name, sysfs_dev->ibdev_name);
+ strcpy(dev->ibdev_path, sysfs_dev->ibdev_path);
- strcpy(dev->dev_path, sys_path);
- strcpy(dev->dev_name, dev_name);
- strcpy(dev->name, ibdev_name);
- strcpy(dev->ibdev_path, ibdev_path);
+ return dev;
+}
- return dev;
- }
+static struct ibv_device *try_drivers(struct ibv_sysfs_dev *sysfs_dev)
+{
+ struct ibv_driver *driver;
+ struct ibv_device *dev;
- fprintf(stderr, PFX "Warning: no userspace device-specific driver found for %s\n"
- " driver search path: ", dev_name);
- if (user_path)
- fprintf(stderr, "%s:", user_path);
- fprintf(stderr, "%s\n", default_path);
+ for (driver = head_driver; driver; driver = driver->next) {
+ dev = try_driver(driver, sysfs_dev);
+ if (dev)
+ return dev;
+ }
return NULL;
}
@@ -217,17 +379,33 @@ static int check_abi_version(const char
return 0;
}
+static void add_device(struct ibv_device *dev,
+ struct ibv_device ***dev_list,
+ int *num_devices,
+ int *list_size)
+{
+ struct ibv_device **new_list;
+
+ if (*list_size <= *num_devices) {
+ *list_size = *list_size ? *list_size * 2 : 1;
+ new_list = realloc(*dev_list, *list_size * sizeof (struct ibv_device *));
+ if (!new_list)
+ return;
+ *dev_list = new_list;
+ }
+
+ (*dev_list)[(*num_devices)++] = dev;
+}
+
HIDDEN int ibverbs_init(struct ibv_device ***list)
{
const char *sysfs_path;
- char *wr_path, *dir;
- char class_path[IBV_SYSFS_PATH_MAX];
- DIR *class_dir;
- struct dirent *dent;
+ struct ibv_sysfs_dev *sysfs_dev, *next_dev;
struct ibv_device *device;
- struct ibv_device **new_list;
int num_devices = 0;
int list_size = 0;
+ int statically_linked = 0;
+ int no_driver = 0;
*list = NULL;
@@ -236,28 +414,6 @@ HIDDEN int ibverbs_init(struct ibv_devic
fprintf(stderr, PFX "Warning: fork()-safety requested "
"but init failed\n");
- find_drivers(default_path);
-
- /*
- * Only follow use path passed in through the calling user's
- * environment if we're not running SUID.
- */
- if (getuid() == geteuid()) {
- user_path = getenv(OPENIB_DRIVER_PATH_ENV);
- if (user_path) {
- wr_path = strdupa(user_path);
- while ((dir = strsep(&wr_path, ";:")))
- find_drivers(dir);
- }
- }
-
- /*
- * Now check if a driver is statically linked. Since we push
- * drivers onto our driver list, the last driver we find will
- * be the first one we try.
- */
- load_driver(NULL);
-
sysfs_path = ibv_get_sysfs_path();
if (!sysfs_path) {
fprintf(stderr, PFX "Fatal: couldn't find sysfs mount.\n");
@@ -267,36 +423,68 @@ HIDDEN int ibverbs_init(struct ibv_devic
if (check_abi_version(sysfs_path))
return 0;
- snprintf(class_path, sizeof class_path, "%s/class/infiniband_verbs",
- sysfs_path);
- class_dir = opendir(class_path);
- if (!class_dir) {
- fprintf(stderr, PFX "Fatal: couldn't open sysfs class "
- "directory '%s'.\n", class_path);
- return 0;
+ read_config();
+
+ find_sysfs_devs();
+
+ for (sysfs_dev = sysfs_dev_list; sysfs_dev; sysfs_dev = sysfs_dev->next) {
+ device = try_drivers(sysfs_dev);
+ if (device) {
+ add_device(device, list, &num_devices, &list_size);
+ sysfs_dev->have_driver = 1;
+ } else
+ no_driver = 1;
}
- while ((dent = readdir(class_dir))) {
- if (dent->d_name[0] == '.' || dent->d_type == DT_REG)
- continue;
+ if (!no_driver)
+ goto out;
+
+ /*
+ * Check if we can dlopen() ourselves. If this fails,
+ * libibverbs is probably statically linked into the
+ * executable, and we should just give up, since trying to
+ * dlopen() a driver module will fail spectacularly (loading a
+ * driver .so will bring in dynamic copies of libibverbs and
+ * libdl to go along with the static copies the executable
+ * has, which quickly leads to a crash.
+ */
+ {
+ void *hand = dlopen(NULL, RTLD_NOW);
+ if (!hand) {
+ fprintf(stderr, PFX "Warning: dlopen(NULL) failed, "
+ "assuming static linking.\n");
+ statically_linked = 1;
+ goto out;
+ }
+ dlclose(hand);
+ }
- device = init_drivers(class_path, dent->d_name);
- if (!device)
+ load_drivers();
+
+ for (sysfs_dev = sysfs_dev_list; sysfs_dev; sysfs_dev = sysfs_dev->next) {
+ if (sysfs_dev->have_driver)
continue;
- if (list_size <= num_devices) {
- list_size = list_size ? list_size * 2 : 1;
- new_list = realloc(*list, list_size * sizeof (struct ibv_device *));
- if (!new_list)
- goto out;
- *list = new_list;
+ device = try_drivers(sysfs_dev);
+ if (device) {
+ add_device(device, list, &num_devices, &list_size);
+ sysfs_dev->have_driver = 1;
}
-
- (*list)[num_devices++] = device;
}
- closedir(class_dir);
-
out:
+ for (sysfs_dev = sysfs_dev_list, next_dev = sysfs_dev->next;
+ sysfs_dev;
+ sysfs_dev = next_dev, next_dev = sysfs_dev ? sysfs_dev->next : NULL) {
+ if (!sysfs_dev->have_driver) {
+ fprintf(stderr, PFX "Warning: no userspace device-specific "
+ "driver found for %s\n", sysfs_dev->sysfs_path);
+ if (statically_linked)
+ fprintf(stderr, " When linking libibverbs statically, "
+ "driver must be statically linked too.\n");
+ }
+ free(sysfs_dev);
+ }
+
return num_devices;
}
diff --git a/src/libibverbs.map b/src/libibverbs.map
index aeb707a..795dd55 100644
--- a/src/libibverbs.map
+++ b/src/libibverbs.map
@@ -77,6 +77,7 @@ IBVERBS_1.0 {
ibv_fork_init;
ibv_dontfork_range;
ibv_dofork_range;
+ ibv_register_driver;
local: *;
};
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