libshare: use AVL tree with static data, pass all data in arguments

This makes it so we don't leak a consistent 64 bytes anymore,
makes the searches simpler and faster, removes /all allocations/
from the driver (quite trivially, since they were absolutely needless),
and makes libshare thread-safe (except, maybe, linux/smb, but that only
does pointer-width loads/stores so it's also mostly fine, except for
leaking smb_shares)

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Ahelenia Ziemiańska <[email protected]>
Closes #13165

4 files changed, 18 insertions, 147 deletions

diff --git a/lib/libshare/os/freebsd/nfs.c b/lib/libshare/os/freebsd/nfs.c
index d0cd5f2b3..388bafc28 100644
--- a/lib/libshare/os/freebsd/nfs.c
+++ b/lib/libshare/os/freebsd/nfs.c
@@ -52,8 +52,6 @@ __FBSDID("$FreeBSD$");
 #define	ZFS_EXPORTS_FILE	"/etc/zfs/exports"
 #define	ZFS_EXPORTS_LOCK	ZFS_EXPORTS_FILE".lock"
 
-static sa_fstype_t *nfs_fstype;
-
 /*
  * This function translates options to a format acceptable by exports(5), eg.
  *
@@ -107,7 +105,7 @@ translate_opts(const char *shareopts, FILE *out)
 static int
 nfs_enable_share_impl(sa_share_impl_t impl_share, FILE *tmpfile)
 {
-	char *shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
+	const char *shareopts = impl_share->sa_shareopts;
 	if (strcmp(shareopts, "on") == 0)
 		shareopts = "";
 
@@ -158,19 +156,6 @@ nfs_validate_shareopts(const char *shareopts)
 	return (SA_OK);
 }
 
-static int
-nfs_update_shareopts(sa_share_impl_t impl_share, const char *shareopts)
-{
-	FSINFO(impl_share, nfs_fstype)->shareopts = (char *)shareopts;
-	return (SA_OK);
-}
-
-static void
-nfs_clear_shareopts(sa_share_impl_t impl_share)
-{
-	FSINFO(impl_share, nfs_fstype)->shareopts = NULL;
-}
-
 /*
  * Commit the shares by restarting mountd.
  */
@@ -201,22 +186,13 @@ start:
 	return (SA_OK);
 }
 
-static const sa_share_ops_t nfs_shareops = {
+sa_fstype_t libshare_nfs_type = {
+	.protocol = "nfs",
+
 	.enable_share = nfs_enable_share,
 	.disable_share = nfs_disable_share,
 	.is_shared = nfs_is_shared,
 
 	.validate_shareopts = nfs_validate_shareopts,
-	.update_shareopts = nfs_update_shareopts,
-	.clear_shareopts = nfs_clear_shareopts,
 	.commit_shares = nfs_commit_shares,
 };
-
-/*
- * Initializes the NFS functionality of libshare.
- */
-void
-libshare_nfs_init(void)
-{
-	nfs_fstype = register_fstype("nfs", &nfs_shareops);
-}
diff --git a/lib/libshare/os/freebsd/smb.c b/lib/libshare/os/freebsd/smb.c
index f14e631b2..fd61d473d 100644
--- a/lib/libshare/os/freebsd/smb.c
+++ b/lib/libshare/os/freebsd/smb.c
@@ -27,8 +27,6 @@
 #include <libshare.h>
 #include "libshare_impl.h"
 
-static sa_fstype_t *smb_fstype;
-
 /*
  * Enables SMB sharing for the specified share.
  */
@@ -71,51 +69,20 @@ smb_is_share_active(sa_share_impl_t impl_share)
 	return (B_FALSE);
 }
 
-/*
- * Called to update a share's options. A share's options might be out of
- * date if the share was loaded from disk and the "sharesmb" dataset
- * property has changed in the meantime. This function also takes care
- * of re-enabling the share if necessary.
- */
-static int
-smb_update_shareopts(sa_share_impl_t impl_share, const char *shareopts)
-{
-	(void) impl_share, (void) shareopts;
-	return (SA_OK);
-}
-
 static int
 smb_update_shares(void)
 {
 	/* Not implemented */
 	return (0);
 }
-/*
- * Clears a share's SMB options. Used by libshare to
- * clean up shares that are about to be free()'d.
- */
-static void
-smb_clear_shareopts(sa_share_impl_t impl_share)
-{
-	FSINFO(impl_share, smb_fstype)->shareopts = NULL;
-}
 
-static const sa_share_ops_t smb_shareops = {
+sa_fstype_t libshare_smb_type = {
+	.protocol = "smb",
+
 	.enable_share = smb_enable_share,
 	.disable_share = smb_disable_share,
 	.is_shared = smb_is_share_active,
 
 	.validate_shareopts = smb_validate_shareopts,
-	.update_shareopts = smb_update_shareopts,
-	.clear_shareopts = smb_clear_shareopts,
 	.commit_shares = smb_update_shares,
 };
-
-/*
- * Initializes the SMB functionality of libshare.
- */
-void
-libshare_smb_init(void)
-{
-	smb_fstype = register_fstype("smb", &smb_shareops);
-}
diff --git a/lib/libshare/os/linux/nfs.c b/lib/libshare/os/linux/nfs.c
index 72653b6d4..f8a34924c 100644
--- a/lib/libshare/os/linux/nfs.c
+++ b/lib/libshare/os/linux/nfs.c
@@ -45,8 +45,6 @@
 #define	ZFS_EXPORTS_FILE	ZFS_EXPORTS_DIR"/zfs.exports"
 #define	ZFS_EXPORTS_LOCK	ZFS_EXPORTS_FILE".lock"
 
-static sa_fstype_t *nfs_fstype;
-
 typedef int (*nfs_shareopt_callback_t)(const char *opt, const char *value,
     void *cookie);
 
@@ -229,7 +227,6 @@ foreach_nfs_host(sa_share_impl_t impl_share, FILE *tmpfile,
     nfs_host_callback_t callback, void *cookie)
 {
 	nfs_host_cookie_t udata;
-	char *shareopts;
 
 	udata.callback = callback;
 	udata.sharepath = impl_share->sa_mountpoint;
@@ -237,10 +234,8 @@ foreach_nfs_host(sa_share_impl_t impl_share, FILE *tmpfile,
 	udata.tmpfile = tmpfile;
 	udata.security = "sys";
 
-	shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
-
-	return (foreach_nfs_shareopt(shareopts, foreach_nfs_host_cb,
-	    &udata));
+	return (foreach_nfs_shareopt(impl_share->sa_shareopts,
+	    foreach_nfs_host_cb, &udata));
 }
 
 /*
@@ -411,11 +406,10 @@ nfs_add_entry(FILE *tmpfile, const char *sharepath,
 static int
 nfs_enable_share_impl(sa_share_impl_t impl_share, FILE *tmpfile)
 {
-	char *shareopts, *linux_opts;
+	char *linux_opts;
 	int error;
 
-	shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
-	error = get_linux_shareopts(shareopts, &linux_opts);
+	error = get_linux_shareopts(impl_share->sa_shareopts, &linux_opts);
 	if (error != SA_OK)
 		return (error);
 
@@ -476,23 +470,6 @@ nfs_validate_shareopts(const char *shareopts)
 }
 
 static int
-nfs_update_shareopts(sa_share_impl_t impl_share, const char *shareopts)
-{
-	FSINFO(impl_share, nfs_fstype)->shareopts = (char *)shareopts;
-	return (SA_OK);
-}
-
-/*
- * Clears a share's NFS options. Used by libshare to
- * clean up shares that are about to be free()'d.
- */
-static void
-nfs_clear_shareopts(sa_share_impl_t impl_share)
-{
-	FSINFO(impl_share, nfs_fstype)->shareopts = NULL;
-}
-
-static int
 nfs_commit_shares(void)
 {
 	char *argv[] = {
@@ -504,22 +481,13 @@ nfs_commit_shares(void)
 	return (libzfs_run_process(argv[0], argv, 0));
 }
 
-static const sa_share_ops_t nfs_shareops = {
+sa_fstype_t libshare_nfs_type = {
+	.protocol = "nfs",
+
 	.enable_share = nfs_enable_share,
 	.disable_share = nfs_disable_share,
 	.is_shared = nfs_is_shared,
 
 	.validate_shareopts = nfs_validate_shareopts,
-	.update_shareopts = nfs_update_shareopts,
-	.clear_shareopts = nfs_clear_shareopts,
 	.commit_shares = nfs_commit_shares,
 };
-
-/*
- * Initializes the NFS functionality of libshare.
- */
-void
-libshare_nfs_init(void)
-{
-	nfs_fstype = register_fstype("nfs", &nfs_shareops);
-}
diff --git a/lib/libshare/os/linux/smb.c b/lib/libshare/os/linux/smb.c
index f4a0bfd6b..91dffc9bb 100644
--- a/lib/libshare/os/linux/smb.c
+++ b/lib/libshare/os/linux/smb.c
@@ -63,8 +63,6 @@
 
 static boolean_t smb_available(void);
 
-static sa_fstype_t *smb_fstype;
-
 static smb_share_t *smb_shares;
 static int smb_disable_share(sa_share_impl_t impl_share);
 static boolean_t smb_is_share_active(sa_share_impl_t impl_share);
@@ -265,19 +263,16 @@ smb_enable_share_one(const char *sharename, const char *sharepath)
 static int
 smb_enable_share(sa_share_impl_t impl_share)
 {
-	char *shareopts;
-
 	if (!smb_available())
 		return (SA_SYSTEM_ERR);
 
 	if (smb_is_share_active(impl_share))
 		smb_disable_share(impl_share);
 
-	shareopts = FSINFO(impl_share, smb_fstype)->shareopts;
-	if (shareopts == NULL) /* on/off */
+	if (impl_share->sa_shareopts == NULL) /* on/off */
 		return (SA_SYSTEM_ERR);
 
-	if (strcmp(shareopts, "off") == 0)
+	if (strcmp(impl_share->sa_shareopts, "off") == 0)
 		return (SA_OK);
 
 	/* Magic: Enable (i.e., 'create new') share */
@@ -361,22 +356,6 @@ smb_is_share_active(sa_share_impl_t impl_share)
 	return (B_FALSE);
 }
 
-/*
- * Called to update a share's options. A share's options might be out of
- * date if the share was loaded from disk and the "sharesmb" dataset
- * property has changed in the meantime. This function also takes care
- * of re-enabling the share if necessary.
- */
-static int
-smb_update_shareopts(sa_share_impl_t impl_share, const char *shareopts)
-{
-	if (!impl_share)
-		return (SA_SYSTEM_ERR);
-
-	FSINFO(impl_share, smb_fstype)->shareopts = (char *)shareopts;
-	return (SA_OK);
-}
-
 static int
 smb_update_shares(void)
 {
@@ -384,24 +363,14 @@ smb_update_shares(void)
 	return (0);
 }
 
-/*
- * Clears a share's SMB options. Used by libshare to
- * clean up shares that are about to be free()'d.
- */
-static void
-smb_clear_shareopts(sa_share_impl_t impl_share)
-{
-	FSINFO(impl_share, smb_fstype)->shareopts = NULL;
-}
+sa_fstype_t libshare_smb_type = {
+	.protocol = "smb",
 
-static const sa_share_ops_t smb_shareops = {
 	.enable_share = smb_enable_share,
 	.disable_share = smb_disable_share,
 	.is_shared = smb_is_share_active,
 
 	.validate_shareopts = smb_validate_shareopts,
-	.update_shareopts = smb_update_shareopts,
-	.clear_shareopts = smb_clear_shareopts,
 	.commit_shares = smb_update_shares,
 };
 
@@ -422,12 +391,3 @@ smb_available(void)
 
 	return (B_TRUE);
 }
-
-/*
- * Initializes the SMB functionality of libshare.
- */
-void
-libshare_smb_init(void)
-{
-	smb_fstype = register_fstype("smb", &smb_shareops);
-}