From 704c787b8c852acea33842744897fea41ca2fb32 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Sun, 12 Nov 2017 21:33:45 +0000
Subject: [PATCH] remount, umount: updates for mtab

Fix parsing in remount
Add umount -a support to the umount tool
---
 Applications/util/remount.c |   4 ++
 Applications/util/umount.c  | 116 +++++++++++++++++++++++++++---------
 2 files changed, 92 insertions(+), 28 deletions(-)

diff --git a/Applications/util/remount.c b/Applications/util/remount.c
index 9a9ad3c9..0b846a91 100644
--- a/Applications/util/remount.c
+++ b/Applications/util/remount.c
@@ -17,7 +17,11 @@ char *getdev(char *arg)
 	if (f) {
 		while (fgets(tmp, sizeof(tmp), f)) {
 			dev = strtok(tmp, " \t");
+			if (*tmp == '#' || dev == NULL)
+				continue;
 			mntpt = strtok(NULL, " \t");
+			if (mntpt == NULL)
+				continue;
 			if ((strcmp(dev, arg) == 0) || (strcmp(mntpt, arg) == 0)) {
 				fclose(f);
 				return strdup(dev);
diff --git a/Applications/util/umount.c b/Applications/util/umount.c
index 273d881b..77ac925e 100644
--- a/Applications/util/umount.c
+++ b/Applications/util/umount.c
@@ -5,19 +5,35 @@
 
 /* Assumed length of a line in /etc/mtab */
 #define MTAB_LINE 160
+#define MAXFS	16
+
+static char *devlist[MAXFS];
+static char **devp = &devlist[0];
+
+static char tmp[MTAB_LINE];
+
+const char *readmtab(FILE *fp)
+{
+    char *dev;
+    while (fgets(tmp, sizeof(tmp), fp) != NULL) {
+        dev = strtok(tmp, " \t");
+        if (dev == NULL || *tmp == '#')
+            continue;
+        return dev;
+    }
+    return NULL;
+}
 
 char *getdev(char *arg)
 {
 	FILE *f;
-	char tmp[MTAB_LINE];
-	char* dev;
+	const char *dev;
 	char* mntpt;
 
 	f = fopen("/etc/mtab", "r");
 	if (f) {
-		while (fgets(tmp, sizeof(tmp), f)) {
-			dev = strtok(tmp, " ");
-			mntpt = strtok(NULL, " ");
+		while ((dev = readmtab(f)) != NULL) {
+			mntpt = strtok(NULL, " \t");
 			if ((strcmp(dev, arg) == 0) || (strcmp(mntpt, arg) == 0)) {
 				fclose(f);
 				return strdup(dev);
@@ -28,8 +44,28 @@ char *getdev(char *arg)
 	return NULL;
 }
 
+int deleted(const char *p)
+{
+	char **d = &devlist[0];
 
-int rm_mtab(char *devname)
+	while(d < devp) {
+		if (*d && strcmp(*d, p) == 0)
+			return 1;
+		d++;
+	}
+	return 0;
+}
+
+static void queue_rm_mtab(const char *p)
+{
+	if (devp == &devlist[MAXFS])
+		fputs("umount: too many file systems.\n", stderr);
+	else
+		*devp++ = strdup(p);
+}
+
+/* FIXME: error checking, atomicity */
+int rewrite_mtab(void)
 {
 	FILE *inpf, *outf;
 	char *tmp_fname;
@@ -37,36 +73,28 @@ int rm_mtab(char *devname)
 	static char tmp2[MTAB_LINE];
 	char* dev;
 
-	if ((tmp_fname = tmpnam(NULL)) == NULL) {
-		perror("Error getting temporary file name");
-		exit(1);
-	}
 	inpf = fopen("/etc/mtab", "r");
 	if (!inpf) {
 		perror("Can't open /etc/mtab");
 		exit(1);
 	}
-	outf = fopen(tmp_fname, "w");
+	outf = fopen("/etc/mtab.new", "w");
 	if (!outf) {
 		perror("Can't create temporary file");
 		exit(1);
 	}
 	while (fgets(tmp, sizeof(tmp), inpf)) {
 		strncpy( tmp2, tmp, MTAB_LINE );
-		dev = strtok(tmp, " ");
-		if (strcmp(dev, devname) == 0) {
+		dev = strtok(tmp, " \t");
+		if (dev && deleted(dev)) {
 			continue;
 		} else {
-			fprintf(outf, "%s", tmp2);
+			fputs(tmp2, outf);
 		}
 	}
 	fclose(inpf);
 	fclose(outf);
-	if (unlink("/etc/mtab") < 0) {
-		perror("Can't delete old /etc/mtab file");
-		exit(1);
-	}
-	if (rename(tmp_fname, "/etc/mtab") < 0) {
+	if (rename("/etc/mtab.new", "/etc/mtab") < 0) {
 		perror("Error installing /etc/mtab");
 		exit(1);
 	}
@@ -75,21 +103,53 @@ int rm_mtab(char *devname)
 
 int main(int argc, char *argv[])
 {
-	char *dev;
+	const char *dev;
+	char **dp;
+	FILE *f;
+	int err = 0;
+
+	umask(022);
 	
 	if (argc != 2) {
 		fprintf(stderr, "%s: umount device\n", argv[0]);
 		return 1;
 	}
-
-	dev = getdev(argv[1]);
-	if (!dev) dev = argv[1];
-	
-	if (umount(dev) == 0) {
-		rm_mtab(dev);
+	if (strcmp(argv[1], "-a") == 0) {
+		/* We need to umount things in reverse order if we have
+		   mounts on mounts */
+		f = fopen("/etc/mtab", "r");
+		if (f == NULL) {
+			perror("mtab");
+			exit(1);
+		}
+		while((dev = readmtab(f)) != NULL) {
+			char *mntpt = strtok(NULL, " \t");
+			/* We can't unmount / */
+			if (strcmp(mntpt, "/"))
+				queue_rm_mtab(dev);
+		}
+		fclose(f);
+		dp = devp;
+		/* Unmount in reverse order of mounting */
+		while(--dp >= devlist) {
+			if (umount(*dp) == -1) {
+				perror(*dp);
+				*dp = NULL;
+				err |= 1;
+			}
+		}
+		rewrite_mtab();
 	} else {
-		perror("umount");
+		dev = getdev(argv[1]);
+		if (!dev)
+			dev = argv[1];
+
+		if (umount(dev) == 0) {
+			queue_rm_mtab(dev);
+			rewrite_mtab();
+		} else
+			perror("umount");
 		return 1;
 	}
-	return 0;
+	return err;
 }
-- 
2.34.1