]> wimlib.net Git - wimlib/blobdiff - src/symlink.c
--hardlink fix
[wimlib] / src / symlink.c
index e243a42a01acc73a34896baf3694332ee34250b3..e7163e584c71b35f810315eed7b285cd8a06151a 100644 (file)
@@ -1,6 +1,8 @@
 #include "dentry.h"
 #include "io.h"
 #include "lookup_table.h"
+#include "sha1.h"
+#include <errno.h>
 
 /*
  * Find the symlink target of a symbolic link or junction point in the WIM.
@@ -12,7 +14,7 @@
  */
 static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
                                char *buf, size_t buf_len,
-                               bool is_junction_point)
+                               u32 reparse_tag)
 {
        const u8 *p = resource;
        u16 substitute_name_offset;
@@ -25,6 +27,7 @@ static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
        unsigned header_size;
        char *translated_target;
        bool is_absolute;
+       u32 flags;
 
        if (resource_len < 12)
                return -EIO;
@@ -32,13 +35,23 @@ static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
        p = get_u16(p, &substitute_name_len);
        p = get_u16(p, &print_name_offset);
        p = get_u16(p, &print_name_len);
-       if (is_junction_point) {
+       get_u32(p, &flags);
+
+       wimlib_assert(reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
+                     reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
+
+       /* I think that some junction points incorrectly get marked as symbolic
+        * links.  So, parse the link buffer as a symlink if the flags seem
+        * plausible. */
+       if (flags <= 1)
+               reparse_tag = WIM_IO_REPARSE_TAG_SYMLINK;
+
+       if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT) {
                header_size = 8;
        } else {
-               u32 flags;
-               p = get_u32(p, &flags);
                is_absolute = (flags & 1) ? false : true;
                header_size = 12;
+               p += 4;
        }
        if (header_size + substitute_name_offset + substitute_name_len > resource_len)
                return -EIO;
@@ -55,7 +68,7 @@ static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
        }
 
        translated_target = link_target;
-       if (is_junction_point || is_absolute) {
+       if (reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT || is_absolute) {
                if (link_target_len < 7
                      || memcmp(translated_target, "\\??\\", 4) != 0
                      || translated_target[4] == '\0'
@@ -66,10 +79,13 @@ static ssize_t get_symlink_name(const u8 *resource, size_t resource_len,
                }
                translated_target += 4;
                link_target_len -= 4;
+               /* There's a drive letter, so just leave the backslashes since
+                * it won't go anyhwere on UNIX anyway... */
+       } else {
+               for (size_t i = 0; i < link_target_len; i++)
+                       if (translated_target[i] == '\\')
+                               translated_target[i] = '/';
        }
-       for (size_t i = 0; i < link_target_len; i++)
-               if (translated_target[i] == '\\')
-                       translated_target[i] = '/';
 
        memcpy(buf, translated_target, link_target_len + 1);
        ret = link_target_len;
@@ -93,13 +109,14 @@ void *make_symlink_reparse_data_buf(const char *symlink_target, size_t *len_ret)
        void *buf = MALLOC(len);
        if (!buf)
                goto out;
+       /* XXX Fix absolute paths */
 
        u8 *p = buf;
        p = put_u16(p, 0); /* Substitute name offset */
        p = put_u16(p, utf16_len); /* Substitute name length */
        p = put_u16(p, utf16_len); /* Print name offset */
        p = put_u16(p, utf16_len); /* Print name length */
-       p = put_u32(p, (symlink_target[0] == '/') ?  0 : 1);
+       p = put_u32(p, 1);
        p = put_bytes(p, utf16_len, name_utf16);
        p = put_bytes(p, utf16_len, name_utf16);
        /*DEBUG("utf16_len = %zu, len = %zu", utf16_len, len);*/
@@ -114,49 +131,108 @@ out:
 ssize_t dentry_readlink(const struct dentry *dentry, char *buf, size_t buf_len,
                        const WIMStruct *w)
 {
-       struct ads_entry *ads;
-       struct lookup_table_entry *entry;
        struct resource_entry *res_entry;
-       bool is_junction_point;
+       struct lookup_table_entry *lte;
+       u16 i = 0;
+       const u8 *hash = dentry->hash;
 
        wimlib_assert(dentry_is_symlink(dentry));
 
-       if (dentry->reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK) {
-               is_junction_point = false;
-               /* 
-                * This is of course not actually documented, but what I think is going
-                * on here is that the symlink dentries have 2 alternate data streams;
-                * one is the default data stream, which is not used and is empty, and
-                * one is the symlink buffer data stream, which is confusingly also
-                * unnamed, but isn't empty as it contains the symlink target within the
-                * resource.
-                */
-               if (dentry->num_ads != 2)
+       while (1) {
+               if ((lte = __lookup_resource(w->lookup_table, hash)))
+                       break;
+               if (i == dentry->num_ads)
                        return -EIO;
-               if ((entry = __lookup_resource(w->lookup_table, dentry->ads_entries[0].hash)))
-                       goto do_readlink;
-               if ((entry = __lookup_resource(w->lookup_table, dentry->ads_entries[1].hash)))
-                       goto do_readlink;
-       } else {
-               wimlib_assert(dentry->reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT);
-
-               is_junction_point = true;
-
-               if ((entry = __lookup_resource(w->lookup_table, dentry->hash)))
-                       goto do_readlink;
+               hash = dentry->ads_entries[i].hash;
+               i++;
        }
-       return -EIO;
-do_readlink:
-       res_entry = &entry->resource_entry;
+       res_entry = &lte->resource_entry;
        if (res_entry->original_size > 10000)
                return -EIO;
-       char res_buf[res_entry->original_size];
-       if (read_full_resource(w->fp, res_entry->size, 
-                              res_entry->original_size,
-                              res_entry->offset,
-                              wim_resource_compression_type(w, res_entry),
-                              res_buf) != 0)
-               return -EIO;
+
+       char __res_buf[res_entry->original_size];
+       const char *res_buf;
+       if (lte->is_symlink && lte->symlink_buf) {
+               res_buf = lte->symlink_buf;
+       } else {
+               res_buf = __res_buf;
+               if (read_full_resource(w->fp, res_entry->size, 
+                                      res_entry->original_size,
+                                      res_entry->offset,
+                                      wim_resource_compression_type(w, res_entry),
+                                      __res_buf) != 0)
+                       return -EIO;
+               res_buf = __res_buf;
+       }
        return get_symlink_name(res_buf, res_entry->original_size, buf,
-                               buf_len, is_junction_point);
+                               buf_len, dentry->reparse_tag);
+}
+
+static int dentry_set_symlink_buf(struct dentry *dentry,
+                                 const u8 symlink_buf_hash[])
+{
+       struct ads_entry *ads_entries;
+
+       ads_entries = CALLOC(2, sizeof(struct ads_entry));
+       if (!ads_entries)
+               return WIMLIB_ERR_NOMEM;
+       memcpy(ads_entries[1].hash, symlink_buf_hash, WIM_HASH_SIZE);
+       dentry_free_ads_entries(dentry);
+       dentry->num_ads = 2;
+       dentry->ads_entries = ads_entries;
+       return 0;
+}
+
+int dentry_set_symlink(struct dentry *dentry, const char *target,
+                      struct lookup_table *lookup_table)
+
+{
+       int ret;
+       size_t symlink_buf_len;
+       struct lookup_table_entry *lte = NULL, *existing_lte;
+       u8 symlink_buf_hash[WIM_HASH_SIZE];
+       void *symlink_buf;
+       
+       symlink_buf = make_symlink_reparse_data_buf(target, &symlink_buf_len);
+       if (!symlink_buf)
+               return WIMLIB_ERR_NOMEM;
+
+       DEBUG("Made symlink reparse data buf (len = %zu, name len = %zu)",
+                       symlink_buf_len, ret);
+       
+       sha1_buffer(symlink_buf, symlink_buf_len, symlink_buf_hash);
+
+       existing_lte = __lookup_resource(lookup_table, symlink_buf_hash);
+
+       if (existing_lte) {
+               existing_lte->refcnt++;
+       } else {
+               DEBUG("Creating new lookup table entry for symlink buf");
+               lte = new_lookup_table_entry();
+               if (!lte) {
+                       ret = WIMLIB_ERR_NOMEM;
+                       goto out_free_symlink_buf;
+               }
+               lte->is_symlink = true;
+               lte->symlink_buf = symlink_buf;
+               lte->resource_entry.original_size = symlink_buf_len;
+               lte->resource_entry.size = symlink_buf_len;
+               memcpy(lte->hash, symlink_buf_hash, WIM_HASH_SIZE);
+       }
+
+       ret = dentry_set_symlink_buf(dentry, symlink_buf_hash);
+
+       if (ret != 0)
+               goto out_free_lte;
+
+       DEBUG("Loaded symlink buf");
+
+       if (!existing_lte)
+               lookup_table_insert(lookup_table, lte);
+       return 0;
+out_free_lte:
+       FREE(lte);
+out_free_symlink_buf:
+       FREE(symlink_buf);
+       return ret;
 }