From 27138ef6d2725a873a9d5cbc4800650026206804 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Thu, 21 Dec 2017 14:11:38 +0000
Subject: [PATCH] mntent: Library methods for managing mtab and fstab

We don't use these or hook them in yet but add them ready
---
 Library/include/mntent.h |  25 +++++++
 Library/libs/mntent.c    | 150 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 175 insertions(+)
 create mode 100644 Library/include/mntent.h
 create mode 100644 Library/libs/mntent.c

diff --git a/Library/include/mntent.h b/Library/include/mntent.h
new file mode 100644
index 00000000..62d27603
--- /dev/null
+++ b/Library/include/mntent.h
@@ -0,0 +1,25 @@
+#ifndef _MNTENT_H
+#define _MNTENT_H
+
+struct mntent {
+    char *mnt_fsname;
+    char *mnt_dir;
+    char *mnt_type;
+    char *mnt_opts;
+    int mnt_freq;
+    int mnt_passno;
+};
+
+#define _MAX_MNTLEN	512
+
+/* Standard functions */
+extern FILE *setmntent(char *filep, char *type);
+extern struct mntent *getmntent(FILE *fp);
+extern int addmntent(FILE *fp, struct mntent *mnt);
+extern int endmntent(FILE *fp);
+extern char *hasmntopt(struct mntent *mnt, char *opt);
+
+/* Extended function found in some Unixen */
+extern int delmntent(FILE *fp, struct mntent *mnt);
+
+#endif
diff --git a/Library/libs/mntent.c b/Library/libs/mntent.c
new file mode 100644
index 00000000..e1af5d74
--- /dev/null
+++ b/Library/libs/mntent.c
@@ -0,0 +1,150 @@
+/*
+ *	An implementation of the mountpoint handling library. This one
+ *	handles all the modern quoting rules for spaces in mount entries
+ *	but does not currently implement the delmntent() extension as we
+ *	can't do that easily without ftruncate().
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <sys/file.h>
+#include <mntent.h>
+
+static char mntbuf[_MAX_MNTLEN];
+
+FILE *setmntent(char *filep, char *type)
+{
+	int lock;
+	FILE *fp = fopen(filep, type);
+	
+	if (fp == NULL)
+		return NULL;
+	if (strchr(type,'w') || strchr(type,'a'))
+		lock = LOCK_SH;
+	else
+		lock = LOCK_EX;
+	if (flock(fileno(fp), lock) == -1) {
+		fclose(fp);
+		return NULL;
+	}
+	return fp;
+}
+
+static int isoct(char c)
+{
+	if (c >= '0' && c <= '7')
+		return 1;
+	return 0;
+}
+
+static int mntparse(char *p, char **t, char *def)
+{
+	char *d = strtok(p, " \t\n");
+	if (d == NULL)
+		d = def;
+	else {
+		/* Dequote */
+		char *s = d;
+		while (*s) {
+			if (*s == '\\' && isoct(s[1]) && isoct(s[2]) && isoct(s[3])) {
+				*d++ = ((s[1] - '0') << 6) | ((s[2] - '0') << 3) | (s[3] - '0');
+				s += 4;
+			} else
+				*d++ = *s++;
+		}
+	}
+	if (t)
+		*t = d;
+	return atoi(d);
+}
+
+struct mntent *getmntent(FILE * fp)
+{
+	static struct mntent me;
+	char *p = mntbuf;
+	/* Skip blank lines and comments */
+	do {
+		if (fgets(mntbuf, _MAX_MNTLEN, fp) == NULL)
+			return NULL;
+	} while(*p == '\n' || *p == '#');
+	mntparse(mntbuf, &me.mnt_fsname, NULL);
+	mntparse(NULL, &me.mnt_dir, NULL);
+	mntparse(NULL, &me.mnt_type, "fuzix");
+	mntparse(NULL, &me.mnt_opts, "");
+	me.mnt_freq = mntparse(NULL, NULL, "0");
+	me.mnt_passno = mntparse(NULL, NULL, "0");
+	if (me.mnt_fsname == NULL || me.mnt_dir == NULL)
+		return NULL;
+	return &me;
+}
+
+void quote_out(char **p, char *s)
+{
+	char *t = *p;
+	if (t == NULL)
+		return;
+	while (t < mntbuf + _MAX_MNTLEN - 1) {
+		if (*s == 0) {
+			*p = t;
+			return;
+		}
+		if (*s == ' ' || *s == '\n' || *s == '\t' || *s == '\\') {
+			if (t < mntbuf + _MAX_MNTLEN - 5) {
+				sprintf(t, "\\%3o", *s);
+				t += 4;
+				s++;
+			} else
+				break;
+		} else {
+			*t++ = *s++;
+		}
+	}
+	/* Overrun */
+	*p = NULL;
+}
+
+void quote_out_int(char **p, int s)
+{
+	quote_out(p, _itoa(s));
+}
+
+int addmntent(FILE * fp, struct mntent *mnt)
+{
+	char *p = mntbuf;
+	quote_out(&p, mnt->mnt_fsname);
+	quote_out(&p, mnt->mnt_dir);
+	quote_out(&p, mnt->mnt_type);
+	quote_out(&p, mnt->mnt_opts);
+	quote_out_int(&p, mnt->mnt_freq);
+	quote_out_int(&p, mnt->mnt_passno);
+	if (p) {
+		*p = '\n';
+		if (fwrite(mntbuf, p - mntbuf, 1, fp) == 1)
+			return 0;
+	}
+	return 1;
+}
+
+int endmntent(FILE *fp)
+{
+	/* Will automatically drop the flock */
+	return fclose(fp);
+}
+
+char *hasmntopt(struct mntent *mnt, char *opt)
+{
+	char *p = mnt->mnt_opts;
+	ssize_t o = strlen(opt);
+
+	while (p) {
+		if (memcmp(p, opt, o) == 0 && (p[o] == ',' || isspace(p[o]) || p[o] == 0 || p[o] == '='))
+			return p;
+		p = strchr(p, ',');
+		if (p)
+			p++;
+	}
+}
-- 
2.34.1