Implement -fstype

Fixes #6!

1 files changed, 174 insertions, 0 deletions

diff --git a/mtab.c b/mtab.c
new file mode 100644
index 0000000..0311c50
--- /dev/null
+++ b/mtab.c
@@ -0,0 +1,174 @@
+/*********************************************************************
+ * bfs                                                               *
+ * Copyright (C) 2017 Tavian Barnes <tavianator@tavianator.com>      *
+ *                                                                   *
+ * This program is free software. It comes without any warranty, to  *
+ * the extent permitted by applicable law. You can redistribute it   *
+ * and/or modify it under the terms of the Do What The Fuck You Want *
+ * To Public License, Version 2, as published by Sam Hocevar. See    *
+ * the COPYING file or http://www.wtfpl.net/ for more details.       *
+ *********************************************************************/
+
+#include "mtab.h"
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#if __linux__
+#	include <mntent.h>
+#elif BSD
+#	include <sys/mount.h>
+#	include <sys/ucred.h>
+#endif
+
+/**
+ * A mount point in the mount table.
+ */
+struct bfs_mtab_entry {
+	/** The device number for this mount point. */
+	dev_t dev;
+	/** The file system type of this mount point. */
+	char *type;
+};
+
+struct bfs_mtab {
+	/** The array of mtab entries. */
+	struct bfs_mtab_entry *table;
+	/** The size of the array. */
+	size_t size;
+	/** Capacity of the array. */
+	size_t capacity;
+};
+
+/**
+ * Add an entry to the mount table.
+ */
+static int bfs_mtab_push(struct bfs_mtab *mtab, dev_t dev, const char *type) {
+	size_t size = mtab->size + 1;
+
+	if (size >= mtab->capacity) {
+		size_t capacity = 2*size;
+		struct bfs_mtab_entry *table = realloc(mtab->table, capacity*sizeof(*table));
+		if (!table) {
+			return -1;
+		}
+		mtab->table = table;
+		mtab->capacity = capacity;
+	}
+
+	struct bfs_mtab_entry *entry = mtab->table + (size - 1);
+	entry->dev = dev;
+	entry->type = strdup(type);
+	if (!entry->type) {
+		return -1;
+	}
+
+	mtab->size = size;
+	return 0;
+}
+
+struct bfs_mtab *parse_bfs_mtab() {
+#if __linux__
+
+	FILE *file = setmntent("/etc/mtab", "r");
+	if (!file) {
+		goto fail;
+	}
+
+	struct bfs_mtab *mtab = malloc(sizeof(*mtab));
+	if (!mtab) {
+		goto fail_file;
+	}
+	mtab->table = NULL;
+	mtab->size = 0;
+	mtab->capacity = 0;
+
+	struct mntent *mnt;
+	while ((mnt = getmntent(file))) {
+		struct stat sb;
+		if (stat(mnt->mnt_dir, &sb) != 0) {
+			continue;
+		}
+
+		if (bfs_mtab_push(mtab, sb.st_dev, mnt->mnt_type) != 0) {
+			goto fail_mtab;
+		}
+	}
+
+	endmntent(file);
+	return mtab;
+
+fail_mtab:
+	free_bfs_mtab(mtab);
+fail_file:
+	endmntent(file);
+fail:
+	return NULL;
+
+#elif BSD
+
+	struct statfs *mntbuf;
+	int size = getmntinfo(&mntbuf, MNT_WAIT);
+	if (size < 0) {
+		return NULL;
+	}
+
+	struct bfs_mtab *mtab = malloc(sizeof(*mtab));
+	if (!mtab) {
+		goto fail;
+	}
+
+	mtab->size = 0;
+	mtab->table = malloc(size*sizeof(*mtab->table));
+	if (!mtab->table) {
+		goto fail_mtab;
+	}
+	mtab->capacity = size;
+
+	for (struct statfs *mnt = mntbuf; mnt < mntbuf + size; ++mnt) {
+		struct stat sb;
+		if (stat(mnt->f_mntonname, &sb) != 0) {
+			continue;
+		}
+
+		if (bfs_mtab_push(mtab, sb.st_dev, mnt->f_fstypename) != 0) {
+			goto fail_mtab;
+		}
+	}
+
+	return mtab;
+
+fail_mtab:
+	free_bfs_mtab(mtab);
+fail:
+	return NULL;
+
+#else
+
+	errno = ENOTSUP;
+	return NULL;
+#endif
+}
+
+const char *bfs_fstype(const struct bfs_mtab *mtab, const struct stat *statbuf) {
+	for (struct bfs_mtab_entry *mnt = mtab->table; mnt < mtab->table + mtab->size; ++mnt) {
+		if (statbuf->st_dev == mnt->dev) {
+			return mnt->type;
+		}
+	}
+
+	return "unknown";
+}
+
+void free_bfs_mtab(struct bfs_mtab *mtab) {
+	if (mtab) {
+		for (struct bfs_mtab_entry *mnt = mtab->table; mnt < mtab->table + mtab->size; ++mnt) {
+			free(mnt->type);
+		}
+		free(mtab->table);
+		free(mtab);
+	}
+}