symlink.c revision 97c607b1a25e1f4e83bf246c76b679d91470f5dc
1f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart/* 2f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * symlink.c --- make a symlink in the filesystem, based on mkdir.c 3f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * 4f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Copyright (c) 2012, Intel Corporation. 5f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * All Rights Reserved. 6f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * 7f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * %Begin-Header% 8f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * This file may be redistributed under the terms of the GNU Library 9f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * General Public License, version 2. 10f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * %End-Header% 11f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 12f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 13f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include "config.h" 14f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <stdio.h> 15f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <string.h> 16f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#if HAVE_UNISTD_H 17f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <unistd.h> 18f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#endif 19f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <fcntl.h> 20f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <time.h> 21f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#if HAVE_SYS_STAT_H 22f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <sys/stat.h> 23f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#endif 24f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#if HAVE_SYS_TYPES_H 25f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include <sys/types.h> 26f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#endif 27f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 28f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include "ext2_fs.h" 29f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart#include "ext2fs.h" 30f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 31f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Harterrcode_t ext2fs_symlink(ext2_filsys fs, ext2_ino_t parent, ext2_ino_t ino, 32f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart const char *name, char *target) 33f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart{ 34f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart errcode_t retval; 35f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart struct ext2_inode inode; 36f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart ext2_ino_t scratch_ino; 37f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart blk64_t blk; 38f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart int fastlink; 39e48bf256e99e4923c6193ff78000af18c700d93dTheodore Ts'o unsigned int target_len; 40f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart char *block_buf = 0; 41f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 42f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 43f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 44f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* The Linux kernel doesn't allow for links longer than a block */ 45f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart target_len = strlen(target); 46f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (target_len > fs->blocksize) { 47f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = EXT2_ET_INVALID_ARGUMENT; 48f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 49f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 50f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 51f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 52f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Allocate a data block for slow links 53f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 54f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart fastlink = (target_len < sizeof(inode.i_block)); 55f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (!fastlink) { 56f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = ext2fs_new_block2(fs, 0, 0, &blk); 57f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval) 58f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 59f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = ext2fs_get_mem(fs->blocksize, &block_buf); 60f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval) 61f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 62f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 63f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 64f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 65f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Allocate an inode, if necessary 66f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 67f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (!ino) { 68f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = ext2fs_new_inode(fs, parent, LINUX_S_IFLNK | 0755, 69f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 0, &ino); 70f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval) 71f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 72f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 73f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 74f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 75f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Create the inode structure.... 76f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 77f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart memset(&inode, 0, sizeof(struct ext2_inode)); 78f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart inode.i_mode = LINUX_S_IFLNK | 0777; 79f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart inode.i_uid = inode.i_gid = 0; 80f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart ext2fs_iblk_set(fs, &inode, fastlink ? 0 : 1); 81f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart inode.i_links_count = 1; 8297c607b1a25e1f4e83bf246c76b679d91470f5dcDarrick J. Wong ext2fs_inode_size_set(fs, &inode, target_len); 83f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* The time fields are set by ext2fs_write_new_inode() */ 84f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 85f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (fastlink) { 86f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* Fast symlinks, target stored in inode */ 87f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart strcpy((char *)&inode.i_block, target); 88f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } else { 89f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* Slow symlinks, target stored in the first block */ 90f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart memset(block_buf, 0, fs->blocksize); 91f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart strcpy(block_buf, target); 92f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (fs->super->s_feature_incompat & 9362f17f36031102a2a40fac338e063c556f73b94aDarrick J. Wong EXT3_FEATURE_INCOMPAT_EXTENTS) { 94f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 95f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * The extent bmap is setup after the inode and block 96f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * have been written out below. 97f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 98f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart inode.i_flags |= EXT4_EXTENTS_FL; 99f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 100f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 101f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 102f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 103f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Write out the inode and inode data block. The inode generation 104f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * number is assigned by write_new_inode, which means that the 105f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * operations using ino must come after it. 106f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 107f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = ext2fs_write_new_inode(fs, ino, &inode); 108f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval) 109f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 110f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 111f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (!fastlink) { 11262f17f36031102a2a40fac338e063c556f73b94aDarrick J. Wong retval = ext2fs_bmap2(fs, ino, &inode, NULL, BMAP_SET, 0, NULL, 11362f17f36031102a2a40fac338e063c556f73b94aDarrick J. Wong &blk); 114f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval) 115f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 116f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 11762f17f36031102a2a40fac338e063c556f73b94aDarrick J. Wong retval = io_channel_write_blk64(fs->io, blk, 1, block_buf); 11862f17f36031102a2a40fac338e063c556f73b94aDarrick J. Wong if (retval) 11962f17f36031102a2a40fac338e063c556f73b94aDarrick J. Wong goto cleanup; 120f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 121f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 122f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 123f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Link the symlink into the filesystem hierarchy 124f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 125f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (name) { 126f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = ext2fs_lookup(fs, parent, name, strlen(name), 0, 127f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart &scratch_ino); 128f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (!retval) { 129f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = EXT2_ET_FILE_EXISTS; 130f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 131f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 132f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval != EXT2_ET_FILE_NOT_FOUND) 133f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 134f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart retval = ext2fs_link(fs, parent, name, ino, EXT2_FT_SYMLINK); 135f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (retval) 136f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart goto cleanup; 137f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart } 138f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 139f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart /* 140f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart * Update accounting.... 141f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart */ 142f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (!fastlink) 143f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart ext2fs_block_alloc_stats2(fs, blk, +1); 144f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart ext2fs_inode_alloc_stats2(fs, ino, +1, 0); 145f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart 146f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hartcleanup: 147f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart if (block_buf) 148f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart ext2fs_free_mem(&block_buf); 149f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart return retval; 150f01c1a6bce5e6674cbfa5260db1691bca01a4410Darren Hart} 151