test: optimise fd closing in forks

Caught while investigating timeouts on a ARM64 server.

Stracing a test process running the eal_flags_autotest, we can see that
the fork helper is checking all possible file descriptors from
getdtablesize() to 2, and close the existing ones.
We can do better by inspecting this forked process /proc/self/fd
directory.

Besides, checking file descriptors via /proc/self/fd only makes sense for
Linux. This code was a noop on FreeBSD.

Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org
Signed-off-by: Krzysztof Kanas <kkanas@marvell.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Tested-by: Krzysztof Kanas <kkanas@marvell.com>
Acked-by: Kevin Traynor <ktraynor@redhat.com>

diff --git a/app/test/process.h b/app/test/process.h
index 128ce41..191d279 100644 (file)
--- a/app/test/process.h
+++ b/app/test/process.h
@@ -11,6 +11,7 @@
 #include <stdlib.h> /* NULL */
 #include <string.h> /* strerror */
 #include <unistd.h> /* readlink */
+#include <dirent.h>
 #include <sys/wait.h>
 
 #include <rte_string_fns.h> /* strlcpy */
@@ -40,7 +41,7 @@ process_dup(const char *const argv[], int numargs, const char *env_value)
 {
        int num;
        char *argv_cpy[numargs + 1];
-       int i, fd, status;
+       int i, status;
        char path[32];
 #ifdef RTE_LIBRTE_PDUMP
        pthread_t thread;
@@ -56,13 +57,50 @@ process_dup(const char *const argv[], int numargs, const char *env_value)
                argv_cpy[i] = NULL;
                num = numargs;
 
-               /* close all open file descriptors, check /proc/self/fd to only
-                * call close on open fds. Exclude fds 0, 1 and 2*/
-               for (fd = getdtablesize(); fd > 2; fd-- ) {
-                       snprintf(path, sizeof(path), "/proc/" exe "/fd/%d", fd);
-                       if (access(path, F_OK) == 0)
+#ifdef RTE_EXEC_ENV_LINUX
+               {
+                       const char *procdir = "/proc/" self "/fd/";
+                       struct dirent *dirent;
+                       char *endptr;
+                       int fd, fdir;
+                       DIR *dir;
+
+                       /* close all open file descriptors, check /proc/self/fd
+                        * to only call close on open fds. Exclude fds 0, 1 and
+                        * 2
+                        */
+                       dir = opendir(procdir);
+                       if (dir == NULL) {
+                               rte_panic("Error opening %s: %s\n", procdir,
+                                               strerror(errno));
+                       }
+
+                       fdir = dirfd(dir);
+                       if (fdir < 0) {
+                               status = errno;
+                               closedir(dir);
+                               rte_panic("Error %d obtaining fd for dir %s: %s\n",
+                                               fdir, procdir,
+                                               strerror(status));
+                       }
+
+                       while ((dirent = readdir(dir)) != NULL) {
+                               errno = 0;
+                               fd = strtol(dirent->d_name, &endptr, 10);
+                               if (errno != 0 || endptr[0] != '\0') {
+                                       printf("Error converting name fd %d %s:\n",
+                                               fd, dirent->d_name);
+                                       continue;
+                               }
+
+                               if (fd == fdir || fd <= 2)
+                                       continue;
+
                                close(fd);
+                       }
+                       closedir(dir);
                }
+#endif
                printf("Running binary with argv[]:");
                for (i = 0; i < num; i++)
                        printf("'%s' ", argv_cpy[i]);