gentoo-overlay/app-arch/tarsync/files/tarsync-0.2.1-symlink.patch

From 6654d41a14da2fc521e889f01669f0dbb89aef15 Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Tue, 5 Oct 2021 23:21:53 -0700
Subject: [PATCH] Symlink support

Bug: https://bugs.gentoo.org/815823
Signed-off-by: Zac Medico <zmedico@gentoo.org>
---
 main.c | 37 +++++++++++++++++++++++++++++++++++--
 tar.c  | 16 ++++++++++++++--
 tar.h  |  2 ++
 3 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/main.c b/main.c
index 2c2da3e..448a9d0 100644
--- a/main.c
+++ b/main.c
@@ -257,7 +257,14 @@ main(int argc, char **argv)
 	// no need to seek.  cfile handles resetting streams as needed
 	
 	for(x=0; x < missing_count; x++) {
-		if(copy_whole_file(&tar_cfh, missing[x]) != 0) {
+		if (missing[x]->type == SYMTYPE) {
+			if(copy_symlink(&tar_cfh, missing[x]) != 0) {
+				v0printf("failed transfering symlink %s\n", missing[x]->fullname);
+				exit(9);
+			}
+			continue;
+		}
+		else if(copy_whole_file(&tar_cfh, missing[x]) != 0) {
 			v0printf("failed transfering file %s\n", missing[x]->fullname);
 			exit(9);
 		}
@@ -673,6 +680,8 @@ int
 check_existing_node(const struct dirent *de, const tar_entry *t, struct stat *st)
 {
 	int type;
+	unsigned char linkname[TAR_LINKNAME_LEN];
+	ssize_t linkname_len;
 	type = convert_lstat_type_tar_type(de->d_name, st);
 	if(type < 0)
 		return -1;
@@ -682,6 +691,15 @@ check_existing_node(const struct dirent *de, const tar_entry *t, struct stat *st
 		return 2;
 	if(REGTYPE == type && (st->st_size != t->size || (check_mtime && t->mtime != st->st_mtime)))
 		return 3;
+	if (SYMTYPE == type) {
+		if ((linkname_len = readlink(de->d_name, linkname, TAR_LINKNAME_LEN)) == -1) {
+			return -1;
+		}
+		if(strncmp((const char *)linkname, (const char *)t->linkname, linkname_len) != 0) {
+			remove_node(de->d_name, st);
+			return 3;
+		}
+	}
 	return 0;
 }
 
@@ -703,7 +721,22 @@ enforce_owner(const char *path, const tar_entry *t, struct stat *st)
 	}
 	return 0;
 }
-	
+
+int
+copy_symlink(cfile *tar_cfh, const tar_entry *ttent)
+{
+	v1printf("creating %s\n", ttent->fullname);
+
+	if (symlink(ttent->linkname, ttent->fullname) != 0) {
+		v0printf("failed creating symlink %s -> %s\n", ttent->fullname, ttent->linkname);
+		return -1;
+	}
+	if(lchown(ttent->fullname, ttent->uid, ttent->gid) != 0) {
+		v0printf("failed chown'ing %s\n", ttent->fullname);
+		return -1;
+	}
+	return 0;
+}
 
 int
 copy_whole_file(cfile *tar_cfh, const tar_entry *ttent) 
diff --git a/tar.c b/tar.c
index 42dc8e7..514e5fb 100644
--- a/tar.c
+++ b/tar.c
@@ -214,8 +214,7 @@ read_entry(cfile *src_cfh, off_u64 start, tar_entry *entry)
 		case AREGTYPE:
 			entry->type = REGTYPE;	break;
 		case SYMTYPE:
-			v0printf("symlinks not supported\n");
-			entry->type = TTAR_UNSUPPORTED_TYPE; break;
+			entry->type = SYMTYPE; break;
 		case LNKTYPE:
 			v0printf("hardlinks not supported!\n");
 			entry->type = TTAR_UNSUPPORTED_TYPE; break;
@@ -242,6 +241,17 @@ read_entry(cfile *src_cfh, off_u64 start, tar_entry *entry)
 	if(get_uid(block + TAR_UNAME_LOC, &entry->uid))
 		entry->uid = octal_str2long(block + TAR_UID_LOC, TAR_UID_LOC);
 
+	if (entry->type == SYMTYPE) {
+		name_len = strnlen((char *)block + TAR_LINKNAME_LOC, TAR_LINKNAME_LEN);
+		if((entry->linkname = (char *)malloc(name_len + 1)) == NULL){
+			v0printf("unable to allocate needed memory, bailing\n");
+			return MEM_ERROR;
+		}
+		memcpy(entry->linkname, block + TAR_LINKNAME_LOC, name_len);
+		entry->linkname[name_len] = '\0';
+		entry->linkname_len = name_len;
+	}
+
 //	if(entry->end % 512)
 //		entry->end += 512 - (entry->end % 512);
 	return 0;
@@ -256,6 +266,8 @@ convert_lstat_type_tar_type(const char *path, struct stat *st)
 	if(S_ISREG(st->st_mode)) {
 		if(st->st_nlink == 1)
 			return REGTYPE;
+	} else if(S_ISLNK(st->st_mode)) {
+			return SYMTYPE;
 	} else if(S_ISDIR(st->st_mode))
 			return DIRTYPE;
 
diff --git a/tar.h b/tar.h
index e9d9ee9..95f957c 100644
--- a/tar.h
+++ b/tar.h
@@ -78,6 +78,8 @@ typedef struct {
 	off_u64			size;
 	unsigned int	fullname_len;
 	char			*fullname;
+	unsigned int	linkname_len;
+	char			*linkname;
 	time_t			mtime;
 	uid_t			uid;
 	gid_t			gid;
-- 
2.32.0