libmount: add support to parse /proc/swaps

Signed-off-by: Karel Zak <kzak@redhat.com>

6 files changed, 206 insertions, 3 deletions

diff --git a/libmount/src/fs.c b/libmount/src/fs.c
index 167d7acef..22addb9f4 100644
--- a/libmount/src/fs.c
+++ b/libmount/src/fs.c
@@ -53,6 +53,7 @@ void mnt_free_fs(struct libmnt_fs *fs)
 	free(fs->tagname);
 	free(fs->tagval);
 	free(fs->root);
+	free(fs->swaptype);
 	free(fs->target);
 	free(fs->fstype);
 	free(fs->optstr);
@@ -147,6 +148,8 @@ struct libmnt_fs *mnt_copy_fs(struct libmnt_fs *dest,
 		goto err;
 	if (cpy_str_at_offset(dest, src, offsetof(struct libmnt_fs, root)))
 		goto err;
+	if (cpy_str_at_offset(dest, src, offsetof(struct libmnt_fs, swaptype)))
+		goto err;
 	if (cpy_str_at_offset(dest, src, offsetof(struct libmnt_fs, target)))
 		goto err;
 	if (cpy_str_at_offset(dest, src, offsetof(struct libmnt_fs, fstype)))
@@ -167,6 +170,9 @@ struct libmnt_fs *mnt_copy_fs(struct libmnt_fs *dest,
 	dest->freq       = src->freq;
 	dest->passno     = src->passno;
 	dest->flags      = src->flags;
+	dest->size	 = src->size;
+	dest->usedsize   = src->usedsize;
+	dest->priority   = src->priority;
 
 	return dest;
 err:
@@ -1017,6 +1023,69 @@ int mnt_fs_set_root(struct libmnt_fs *fs, const char *root)
 }
 
 /**
+ * mnt_fs_get_swaptype:
+ * @fs: /proc/swaps entry
+ *
+ * Returns: swap type or NULL
+ */
+const char *mnt_fs_get_swaptype(struct libmnt_fs *fs)
+{
+	assert(fs);
+	return fs ? fs->swaptype : NULL;
+}
+
+/**
+ * mnt_fs_get_size:
+ * @fs: /proc/swaps entry
+ *
+ * Returns: size
+ */
+off_t mnt_fs_get_size(struct libmnt_fs *fs)
+{
+	assert(fs);
+	return fs ? fs->size : 0;
+}
+
+/**
+ * mnt_fs_get_usedsize:
+ * @fs: /proc/swaps entry
+ *
+ * Returns: used size
+ */
+off_t mnt_fs_get_usedsize(struct libmnt_fs *fs)
+{
+	assert(fs);
+	return fs ? fs->usedsize : 0;
+}
+
+/**
+ * mnt_fs_get_priority:
+ * @fs: /proc/swaps entry
+ *
+ * Returns: priority
+ */
+int mnt_fs_get_priority(struct libmnt_fs *fs)
+{
+	assert(fs);
+	return fs ? fs->priority : 0;
+}
+
+/**
+ * mnt_fs_set_priority:
+ * @fs: /proc/swaps entry
+ *
+ * Returns: 0 or -1 in case of error
+ */
+int mnt_fs_set_priority(struct libmnt_fs *fs, int prio)
+{
+	assert(fs);
+	if (!fs)
+		return -EINVAL;
+	fs->priority = prio;
+	return 0;
+}
+
+/**
  * mnt_fs_get_bindsrc:
  * @fs: /run/mount/utab entry
  *
@@ -1314,6 +1383,16 @@ int mnt_fs_print_debug(struct libmnt_fs *fs, FILE *file)
 
 	if (mnt_fs_get_root(fs))
 		fprintf(file, "root:   %s\n", mnt_fs_get_root(fs));
+
+	if (mnt_fs_get_swaptype(fs))
+		fprintf(file, "swaptype: %s\n", mnt_fs_get_swaptype(fs));
+	if (mnt_fs_get_size(fs))
+		fprintf(file, "size: %jd\n", mnt_fs_get_size(fs));
+	if (mnt_fs_get_usedsize(fs))
+		fprintf(file, "usedsize: %jd\n", mnt_fs_get_usedsize(fs));
+	if (mnt_fs_get_priority(fs))
+		fprintf(file, "priority: %d\n", mnt_fs_get_priority(fs));
+
 	if (mnt_fs_get_bindsrc(fs))
 		fprintf(file, "bindsrc: %s\n", mnt_fs_get_bindsrc(fs));
 	if (mnt_fs_get_freq(fs))
diff --git a/libmount/src/libmount.h.in b/libmount/src/libmount.h.in
index fbabec5c8..a3eaa9ea6 100644
--- a/libmount/src/libmount.h.in
+++ b/libmount/src/libmount.h.in
@@ -131,6 +131,7 @@ extern int mnt_fstype_is_pseudofs(const char *type);
 extern int mnt_match_fstype(const char *type, const char *pattern);
 extern int mnt_match_options(const char *optstr, const char *pattern);
 extern const char *mnt_get_fstab_path(void);
+extern const char *mnt_get_swaps_path(void);
 extern const char *mnt_get_mtab_path(void);
 extern int mnt_has_regular_mtab(const char **mtab, int *writable);
 
@@ -259,6 +260,11 @@ extern int mnt_fs_get_id(struct libmnt_fs *fs);
 extern int mnt_fs_get_parent_id(struct libmnt_fs *fs);
 extern dev_t mnt_fs_get_devno(struct libmnt_fs *fs);
 
+extern const char *mnt_fs_get_swaptype(struct libmnt_fs *fs);
+extern off_t mnt_fs_get_size(struct libmnt_fs *fs);
+extern off_t mnt_fs_get_usedsize(struct libmnt_fs *fs);
+extern int mnt_fs_get_priority(struct libmnt_fs *fs);
+
 extern int mnt_fs_match_target(struct libmnt_fs *fs, const char *target,
 			       struct libmnt_cache *cache);
 extern int mnt_fs_match_source(struct libmnt_fs *fs, const char *source,
@@ -284,6 +290,7 @@ extern int mnt_table_parse_file(struct libmnt_table *tb, const char *filename);
 extern int mnt_table_parse_dir(struct libmnt_table *tb, const char *dirname);
 
 extern int mnt_table_parse_fstab(struct libmnt_table *tb, const char *filename);
+extern int mnt_table_parse_swaps(struct libmnt_table *tb, const char *filename);
 extern int mnt_table_parse_mtab(struct libmnt_table *tb, const char *filename);
 extern int mnt_table_set_parser_errcb(struct libmnt_table *tb,
                 int (*cb)(struct libmnt_table *tb, const char *filename, int line));
diff --git a/libmount/src/libmount.sym b/libmount/src/libmount.sym
index 48860e870..c09f6ce2a 100644
--- a/libmount/src/libmount.sym
+++ b/libmount/src/libmount.sym
@@ -233,4 +233,10 @@ global:
 	mnt_context_is_loopdel;
 	mnt_context_is_nocanonicalize;
 	mnt_context_is_nohelpers;
+	mnt_table_parse_swaps;
+	mnt_get_swaps_path;
+	mnt_fs_get_swaptype;
+	mnt_fs_get_size;
+	mnt_fs_get_usedsize;
+	mnt_fs_get_priority;
 } MOUNT_2.21;
diff --git a/libmount/src/mountP.h b/libmount/src/mountP.h
index fa0edf50c..ee5e94fb2 100644
--- a/libmount/src/mountP.h
+++ b/libmount/src/mountP.h
@@ -194,7 +194,7 @@ struct libmnt_fs {
 
 	char		*bindsrc;	/* utab, full path from fstab[1] for bind mounts */
 
-	char		*source;	/* fstab[1], mountinfo[10]:
+	char		*source;	/* fstab[1], mountinfo[10], swaps[1]:
                                          * source dev, file, dir or TAG */
 	char		*tagname;	/* fstab[1]: tag name - "LABEL", "UUID", ..*/
 	char		*tagval;	/*           tag value */
@@ -212,6 +212,12 @@ struct libmnt_fs {
 	int		freq;		/* fstab[5]: dump frequency in days */
 	int		passno;		/* fstab[6]: pass number on parallel fsck */
 
+	/* /proc/swaps */
+	char		*swaptype;	/* swaps[2]: device type (partition, file, ...) */
+	off_t		size;		/* swaps[3]: swaparea size */
+	off_t		usedsize;	/* swaps[4]: used size */
+	int		priority;	/* swaps[5]: swap priority */
+
 	int		flags;		/* MNT_FS_* flags */
 
 	void		*userdata;	/* library independent data */
@@ -255,7 +261,8 @@ enum {
 	MNT_FMT_FSTAB,			/* /etc/{fs,m}tab */
 	MNT_FMT_MTAB = MNT_FMT_FSTAB,	/* alias */
 	MNT_FMT_MOUNTINFO,		/* /proc/#/mountinfo */
-	MNT_FMT_UTAB			/* /dev/.mount/utab */
+	MNT_FMT_UTAB,			/* /run/mount/utab */
+	MNT_FMT_SWAPS			/* /proc/swaps */
 };
 
 
diff --git a/libmount/src/tab_parse.c b/libmount/src/tab_parse.c
index 6d3e21d21..73a7f83c8 100644
--- a/libmount/src/tab_parse.c
+++ b/libmount/src/tab_parse.c
@@ -269,6 +269,56 @@ enomem:
 }
 
 /*
+ * Parses one line from /proc/swaps
+ */
+static int mnt_parse_swaps_line(struct libmnt_fs *fs, char *s)
+{
+	uintmax_t fsz, usz;
+	int rc;
+	char *src = NULL;
+
+	rc = sscanf(s,	UL_SCNsA" "	/* (1) source */
+			UL_SCNsA" "	/* (2) type */
+			"%jd"		/* (3) size */
+			"%jd"		/* (4) used */
+			"%d",		/* priority */
+
+			&src,
+			&fs->swaptype,
+			&fsz,
+			&usz,
+			&fs->priority);
+
+	if (rc == 5) {
+		size_t sz;
+
+		fs->size = fsz;
+		fs->usedsize = usz;
+
+		unmangle_string(src);
+
+		/* remove "(deleted)" suffix */
+		sz = strlen(src);
+		if (sz > PATH_DELETED_SUFFIX_SZ) {
+			char *p = src + (sz - PATH_DELETED_SUFFIX_SZ);
+			if (strcmp(p, PATH_DELETED_SUFFIX) == 0)
+				*p = '\0';
+		}
+
+		rc = mnt_fs_set_source(fs, src);
+		if (!rc)
+			mnt_fs_set_fstype(fs, "swap");
+		free(src);
+	} else {
+		DBG(TAB, mnt_debug("tab parse error: [sscanf rc=%d]: '%s'", rc, s));
+		rc = -EINVAL;
+	}
+
+	return rc;
+}
+
+
+/*
  * Returns {m,fs}tab or mountinfo file format (MNT_FMT_*)
  *
  * Note that we aren't trying to guess utab file format, because this file has
@@ -281,9 +331,14 @@ static int guess_table_format(char *line)
 {
 	unsigned int a, b;
 
+	DBG(TAB, mnt_debug("trying to guess table type"));
+
 	if (sscanf(line, "%u %u", &a, &b) == 2)
 		return MNT_FMT_MOUNTINFO;
 
+	if (strncmp(line, "Filename\t", 9) == 0)
+		return MNT_FMT_SWAPS;
+
 	return MNT_FMT_FSTAB;		/* fstab, mtab or /proc/mounts */
 }
 
@@ -302,6 +357,7 @@ static int mnt_table_parse_next(struct libmnt_table *tb, FILE *f, struct libmnt_
 	assert(fs);
 
 	/* read the next non-blank non-comment line */
+next_line:
 	do {
 		if (fgets(buf, sizeof(buf), f) == NULL)
 			return -EINVAL;
@@ -327,8 +383,11 @@ static int mnt_table_parse_next(struct libmnt_table *tb, FILE *f, struct libmnt_
 		s = skip_spaces(buf);
 	} while (*s == '\0' || *s == '#');
 
-	if (tb->fmt == MNT_FMT_GUESS)
+	if (tb->fmt == MNT_FMT_GUESS) {
 		tb->fmt = guess_table_format(s);
+		if (tb->fmt == MNT_FMT_SWAPS)
+			goto next_line;			/* skip swap header */
+	}
 
 	switch (tb->fmt) {
 	case MNT_FMT_FSTAB:
@@ -340,6 +399,11 @@ static int mnt_table_parse_next(struct libmnt_table *tb, FILE *f, struct libmnt_
 	case MNT_FMT_UTAB:
 		rc = mnt_parse_utab_line(fs, s);
 		break;
+	case MNT_FMT_SWAPS:
+		if (strncmp(s, "Filename\t", 9) == 0)
+			goto next_line;			/* skip swap header */
+		rc = mnt_parse_swaps_line(fs, s);
+		break;
 	default:
 		rc = -1;	/* unknown format */
 		break;
@@ -350,6 +414,7 @@ static int mnt_table_parse_next(struct libmnt_table *tb, FILE *f, struct libmnt_
 err:
 	DBG(TAB, mnt_debug_h(tb, "%s:%d: %s parse error", filename, *nlines,
 				tb->fmt == MNT_FMT_MOUNTINFO ? "mountinfo" :
+				tb->fmt == MNT_FMT_SWAPS ? "swaps" :
 				tb->fmt == MNT_FMT_FSTAB ? "tab" : "utab"));
 
 	/* by default all errors are recoverable, otherwise behavior depends on
@@ -657,6 +722,34 @@ int mnt_table_set_parser_errcb(struct libmnt_table *tb,
 }
 
 /**
+ * mnt_table_parse_swaps:
+ * @tb: table
+ * @filename: overwrites default (/proc/swaps or $LIBMOUNT_SWAPS) or NULL
+ *
+ * This function parses /proc/swaps and appends new lines to the @tab.
+ *
+ * See also mnt_table_set_parser_errcb().
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int mnt_table_parse_swaps(struct libmnt_table *tb, const char *filename)
+{
+	assert(tb);
+
+	if (!tb)
+		return -EINVAL;
+	if (!filename) {
+		filename = mnt_get_swaps_path();
+		if (!filename)
+			return -EINVAL;
+	}
+
+	tb->fmt = MNT_FMT_SWAPS;
+
+	return mnt_table_parse_file(tb, filename);
+}
+
+/**
  * mnt_table_parse_fstab:
  * @tb: table
  * @filename: overwrites default (/etc/fstab or $LIBMOUNT_FSTAB) or NULL
diff --git a/libmount/src/utils.c b/libmount/src/utils.c
index ca1eb88d8..e740d83d0 100644
--- a/libmount/src/utils.c
+++ b/libmount/src/utils.c
@@ -705,6 +705,17 @@ done:
 }
 
 /**
+ * mnt_get_swaps_path:
+ *
+ * Returns: path to /proc/swaps or $LIBMOUNT_SWAPS.
+ */
+const char *mnt_get_swaps_path(void)
+{
+	const char *p = safe_getenv("LIBMOUNT_SWAPS");
+	return p ? : _PATH_PROC_SWAPS;
+}
+
+/**
  * mnt_get_fstab_path:
  *
  * Returns: path to /etc/fstab or $LIBMOUNT_FSTAB.