Add a quick test program to detect file system type

Intended to help with identifying shared tmp dirs.

Signed-off-by: Ralph Castain <rhc@pmix.org>

.gitignore

@@ -185,6 +185,7 @@ test/filegen
 test/iostress
 test/spawn_multiple
 test/clichk
+test/chkfs
 
 docs/_build
 docs/_static

test/Makefile

@@ -51,7 +51,8 @@ TESTS = \
 	qspawn \
 	iostress \
 	filegen \
-	clichk
+	clichk \
+	chkfs
 
 all: $(TESTS)
 

test/chkfs.c

@@ -0,0 +1,83 @@
+#define _GNU_SOURCE
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <mntent.h>
+#include <string.h>
+ #include <fcntl.h>
+
+//#define MOUNT_FILE "/etc/mtab"
+#define MOUNT_FILE "/proc/mounts"
+
+static int mountpoint(char *filename, char **fstype)
+{
+    struct stat s;
+    struct mntent mnt;
+    FILE *fp;
+    dev_t dev;
+    char buf[1024];
+    int fd;
+
+    fd = open(filename, O_RDONLY);
+    if (0 > fd) {
+        fprintf(stderr, "CANNOT OPEN %s\n", filename);
+        return EINVAL;
+    }
+    if (fstat(fd, &s) != 0) {
+        return EINVAL;
+    }
+    close(fd);
+
+    dev = s.st_dev;
+
+    if ((fp = setmntent(MOUNT_FILE, "r")) == NULL) {
+        return EINVAL;
+    }
+
+    while (getmntent_r(fp, &mnt, buf, sizeof(buf))) {
+        fprintf(stderr, "MNT: %s %s\n", mnt.mnt_fsname, mnt.mnt_dir);
+        fd = open(mnt.mnt_dir, O_RDONLY);
+        if (0 > fd) {
+            // probably lack permissions
+            continue;
+        }
+        if (fstat(fd, &s) != 0) {
+            close(fd);
+            continue;
+        }
+
+        if (s.st_dev == dev) {
+            *fstype = strdup(mnt.mnt_type);
+            close(fd);
+            return 0;
+        }
+        close(fd);
+    }
+
+    endmntent(fp);
+
+    // Should never reach here.
+    return EINVAL;
+}
+
+int main(int argc, char **argv)
+{
+    int n, rc;
+    char *fstype;
+
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s file1 file2 ...\n", argv[0]);
+        return 1;
+    }
+
+    for (n=1; NULL != argv[n]; n++) {
+        rc = mountpoint(argv[n], &fstype);
+        fprintf(stdout, "Return: %d File: %s FStype: %s\n", rc, argv[n], fstype);
+        free(fstype);
+    }
+
+    return 0;
+}