autofs-5.0.7 - add symlink pseudo option

From: Ian Kent <raven@themaw.net>

Add a "symlink" pseudo option to tell the bind mount module to symlink

instead of bind when mounting mounts other than direct mounts and

non-root indirect mount offset mounts (aka. non-root multi-mount

entries).

---

 CHANGELOG              |    1 +

 include/automount.h    |    3 +++

 lib/master_parse.y     |    8 +++++++-

 lib/master_tok.l       |    1 +

 man/auto.master.5.in   |    8 ++++++++

 modules/mount_autofs.c |    5 +++++

 modules/mount_bind.c   |   36 +++++++++++++++++++++++++++++++++++-

 7 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG

index c189483..247d334 100644

--- a/CHANGELOG

+++ b/CHANGELOG

@@ -32,6 +32,7 @@

 - fix wildcard multi map regression.

 - fix file descriptor leak when reloading the daemon.

 - depricate nosymlink pseudo option.

+- add symlink pseudo option.

 25/07/2012 autofs-5.0.7

 =======================

diff --git a/include/automount.h b/include/automount.h

index 37541f5..e72fa0d 100644

--- a/include/automount.h

+++ b/include/automount.h

@@ -455,6 +455,9 @@ struct kernel_mod_version {

 /* Don't use bind mounts even when system supports them */

 #define MOUNT_FLAG_NOBIND		0x0020

+/* Use symlinks instead of bind mounting local mounts */

+#define MOUNT_FLAG_SYMLINK		0x0040

+

 struct autofs_point {

 	pthread_t thid;

 	char *path;			/* Mount point name */

diff --git a/lib/master_parse.y b/lib/master_parse.y

index f925b5a..11caf5b 100644

--- a/lib/master_parse.y

+++ b/lib/master_parse.y

@@ -57,6 +57,7 @@ static char *type;

 static char *format;

 static long timeout;

 static long negative_timeout;

+static unsigned symlnk;

 static unsigned nobind;

 static unsigned ghost;

 extern unsigned global_selection_options;

@@ -100,7 +101,7 @@ static int master_fprintf(FILE *, char *, ...);

 %token COMMENT

 %token MAP

 %token OPT_TIMEOUT OPT_NTIMEOUT OPT_NOBIND OPT_NOGHOST OPT_GHOST OPT_VERBOSE

-%token OPT_DEBUG OPT_RANDOM OPT_USE_WEIGHT

+%token OPT_DEBUG OPT_RANDOM OPT_USE_WEIGHT OPT_SYMLINK

 %token COLON COMMA NL DDASH

 %type <strtype> map

 %type <strtype> options

@@ -186,6 +187,7 @@ line:

 	| PATH OPT_USE_WEIGHT { master_notify($1); YYABORT; }

 	| PATH OPT_DEBUG { master_notify($1); YYABORT; }

 	| PATH OPT_TIMEOUT { master_notify($1); YYABORT; }

+	| PATH OPT_SYMLINK { master_notify($1); YYABORT; }

 	| PATH OPT_NOBIND { master_notify($1); YYABORT; }

 	| PATH OPT_GHOST { master_notify($1); YYABORT; }

 	| PATH OPT_NOGHOST { master_notify($1); YYABORT; }

@@ -557,6 +559,7 @@ option: daemon_option

 daemon_option: OPT_TIMEOUT NUMBER { timeout = $2; }

 	| OPT_NTIMEOUT NUMBER { negative_timeout = $2; }

+	| OPT_SYMLINK	{ symlnk = 1; }

 	| OPT_NOBIND	{ nobind = 1; }

 	| OPT_NOGHOST	{ ghost = 0; }

 	| OPT_GHOST	{ ghost = 1; }

@@ -627,6 +630,7 @@ static void local_init_vars(void)

 	debug = 0;

 	timeout = -1;

 	negative_timeout = 0;

+	symlnk = 0;

 	nobind = 0;

 	ghost = defaults_get_browse_mode();

 	random_selection = global_selection_options & MOUNT_FLAG_RANDOM_SELECT;

@@ -811,6 +815,8 @@ int master_parse_entry(const char *buffer, unsigned int default_timeout, unsigne

 		entry->ap->flags |= MOUNT_FLAG_RANDOM_SELECT;

 	if (use_weight)

 		entry->ap->flags |= MOUNT_FLAG_USE_WEIGHT_ONLY;

+	if (symlnk)

+		entry->ap->flags |= MOUNT_FLAG_SYMLINK;

 	if (negative_timeout)

 		entry->ap->negative_timeout = negative_timeout;

diff --git a/lib/master_tok.l b/lib/master_tok.l

index 30abb15..f9b4e55 100644

--- a/lib/master_tok.l

+++ b/lib/master_tok.l

@@ -361,6 +361,7 @@ OPTNTOUT	(-n{OPTWS}|-n{OPTWS}={OPTWS}|--negative-timeout{OPTWS}|--negative-timeo

 		return(NUMBER);

 	}

+	-?symlink		{ return(OPT_SYMLINK); }

 	-?nobind		{ return(OPT_NOBIND); }

 	-?nobrowse		{ return(OPT_NOGHOST); }

 	-g|--ghost|-?browse	{ return(OPT_GHOST); }

diff --git a/man/auto.master.5.in b/man/auto.master.5.in

index 8007542..bbea43a 100644

--- a/man/auto.master.5.in

+++ b/man/auto.master.5.in

@@ -159,6 +159,14 @@ on individual map entries of both types. Bind mounting of NFS file

 systems can also be prevented for specific map entrys by adding the

 "port=" mount option to the entries.

 .TP

+.I "symlink"

+This option makes bind mounting use a symlink instead of an actual bind

+mount. It is an autofs specific option that is a pseudo mount option and

+so is given without a leading dash. It may be used with indirect map

+entries only, either in the master map (so it effects all map entries)

+or with individual map entries. The option is ignored for direct mounts

+and non-root offest mount entries.

+.TP

 .I "\-r, \-\-random-multimount-selection"

 Enables the use of ramdom selection when choosing a host from a

 list of replicated servers. This option is applied to this mount

diff --git a/modules/mount_autofs.c b/modules/mount_autofs.c

index ef16020..8c1e600 100644

--- a/modules/mount_autofs.c

+++ b/modules/mount_autofs.c

@@ -51,6 +51,7 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name,

 	int argc, status;

 	int nobind = ap->flags & MOUNT_FLAG_NOBIND;

 	int ghost = ap->flags & MOUNT_FLAG_GHOST;

+	int symlnk = ap->flags & MOUNT_FLAG_SYMLINK;

 	time_t timeout = ap->entry->maps->exp_timeout;

 	unsigned logopt = ap->logopt;

 	struct map_type_info *info;

@@ -120,6 +121,8 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name,

 				nobind = 1;

 			else if (strncmp(cp, "browse", 6) == 0)

 				ghost = 1;

+			else if (strncmp(cp, "symlink", 7) == 0)

+				symlnk = 1;

 			else if (strncmp(cp, "timeout=", 8) == 0) {

 				char *val = strchr(cp, '=');

 				unsigned tout;

@@ -158,6 +161,8 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name,

 	}

 	nap = entry->ap;

 	nap->parent = ap;

+	if (symlnk)

+		nap->flags |= MOUNT_FLAG_SYMLINK;

 	argc = 1;

diff --git a/modules/mount_bind.c b/modules/mount_bind.c

index 9bce686..4975294 100644

--- a/modules/mount_bind.c

+++ b/modules/mount_bind.c

@@ -73,10 +73,44 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name, int

 	char buf[MAX_ERR_BUF];

 	int err;

 	int i, len;

+	int symlnk = (*name != '/' && (ap->flags & MOUNT_FLAG_SYMLINK));

 	if (ap->flags & MOUNT_FLAG_REMOUNT)

 		return 0;

+	/* Extract "symlink" pseudo-option which forces local filesystems

+	 * to be symlinked instead of bound.

+	 */

+	if (*name != '/' && !symlnk && options) {

+		const char *comma;

+		int o_len = strlen(options) + 1;

+

+		for (comma = options; *comma != '\0';) {

+			const char *cp;

+			const char *end;

+

+			while (*comma == ',')

+				comma++;

+

+			/* Skip leading white space */

+			while (*comma == ' ' || *comma == '\t')

+				comma++;

+

+			cp = comma;

+			while (*comma != '\0' && *comma != ',')

+				comma++;

+

+			/* Skip trailing white space */

+			end = comma - 1;

+			while (*comma == ' ' || *comma == '\t')

+				end--;

+

+			o_len = end - cp + 1;

+			if (strncmp("symlink", cp, o_len) == 0)

+				symlnk = 1;

+		}

+	}

+

 	/* Root offset of multi-mount */

 	len = strlen(root);

 	if (root[len - 1] == '/') {

@@ -100,7 +134,7 @@ int mount_mount(struct autofs_point *ap, const char *root, const char *name, int

 	if (options == NULL || *options == '\0')

 		options = "defaults";

-	if (bind_works) {

+	if (!symlnk && bind_works) {

 		int status, existed = 1;

 		debug(ap->logopt, MODPREFIX "calling mkdir_path %s", fullpath);