eal/linux: support built-in kernel modules

Currently rte_eal_check_module() detects Linux kernel modules via reading
/proc/modules. Built-in ones aren't listed there and therefore they are not
being found.

Add support for checking built-in modules with parsing the sysfs files

This commit obsoletes the /proc/modules parsing approach.

Signed-off-by: Kamil Rytarowski <kamil.rytarowski@caviumnetworks.com>
Acked-by: David Marchand <david.marchand@6wind.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 635ec36..4d3e0de 100644 (file)
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -49,6 +49,7 @@
 #include <errno.h>
 #include <sys/mman.h>
 #include <sys/queue.h>
+#include <sys/stat.h>
 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686)
 #include <sys/io.h>
 #endif
@@ -901,27 +902,33 @@ int rte_eal_has_hugepages(void)
 int
 rte_eal_check_module(const char *module_name)
 {
-       char mod_name[30]; /* Any module names can be longer than 30 bytes? */
-       int ret = 0;
+       char sysfs_mod_name[PATH_MAX];
+       struct stat st;
        int n;
 
        if (NULL == module_name)
                return -1;
 
-       FILE *fd = fopen("/proc/modules", "r");
-       if (NULL == fd) {
-               RTE_LOG(ERR, EAL, "Open /proc/modules failed!"
-                       " error %i (%s)\n", errno, strerror(errno));
+       /* Check if there is sysfs mounted */
+       if (stat("/sys/module", &st) != 0) {
+               RTE_LOG(DEBUG, EAL, "sysfs is not mounted! error %i (%s)\n",
+                       errno, strerror(errno));
                return -1;
        }
-       while (!feof(fd)) {
-               n = fscanf(fd, "%29s %*[^\n]", mod_name);
-               if ((n == 1) && !strcmp(mod_name, module_name)) {
-                       ret = 1;
-                       break;
-               }
+
+       /* A module might be built-in, therefore try sysfs */
+       n = snprintf(sysfs_mod_name, PATH_MAX, "/sys/module/%s", module_name);
+       if (n < 0 || n > PATH_MAX) {
+               RTE_LOG(DEBUG, EAL, "Could not format module path\n");
+               return -1;
        }
-       fclose(fd);
 
-       return ret;
+       if (stat(sysfs_mod_name, &st) != 0) {
+               RTE_LOG(DEBUG, EAL, "Module %s not found! error %i (%s)\n",
+                       sysfs_mod_name, errno, strerror(errno));
+               return 0;
+       }
+
+       /* Module has been found */
+       return 1;
 }