Change lzf to handle values larger than UINT32_MAX (#9776)

Redis supports inserting data over 4GB into string (and recently for lists too, see #9357),
But LZF compression used in RDB files (see `rdbcompression` config), and in quicklist
(see `list-compress-depth` config) does not support compress/decompress data over
UINT32_MAX, which will result in corrupting the rdb after compression.

Internal changes:
1. Modify the `unsigned int` parameter of `lzf_compress/lzf_decompress` to `size_t`.
2. Modify the variable types in `lzf_compress` involving offsets and lengths to `size_t`.
3. Set LZF_USE_OFFSETS to 0.
    When LZF_USE_OFFSETS is 1, lzf store offset into `LZF_HSLOT`(32bit). 
    Even in 64-bit, `LZF_USE_OFFSETS` defaults to 1, because lzf assumes that it only
    compresses and decompresses data smaller than UINT32_MAX.
    But now we need to make lzf support 64-bit, turning on `LZF_USE_OFFSETS` will make
    it impossible to store 64-bit offsets or pointers.
    BTW, disable LZF_USE_OFFSETS also brings a few performance improvements.

Tests:
1. Add test for compress/decompress string large than UINT32_MAX.
2. Add unittest for compress/decompress quicklistNode.

6 files changed, 109 insertions, 17 deletions

diff --git a/src/lzf.h b/src/lzf.h
index 98e038f31..45ddfa8da 100644
--- a/src/lzf.h
+++ b/src/lzf.h
@@ -73,9 +73,9 @@
  * and lzf_c.c.
  *
  */
-unsigned int
-lzf_compress (const void *const in_data,  unsigned int in_len,
-              void             *out_data, unsigned int out_len);
+size_t
+lzf_compress (const void *const in_data,  size_t in_len,
+              void             *out_data, size_t out_len);
 
 /*
  * Decompress data compressed with some version of the lzf_compress
@@ -92,9 +92,9 @@ lzf_compress (const void *const in_data,  unsigned int in_len,
  *
  * This function is very fast, about as fast as a copying loop.
  */
-unsigned int
-lzf_decompress (const void *const in_data,  unsigned int in_len,
-                void             *out_data, unsigned int out_len);
+size_t
+lzf_decompress (const void *const in_data,  size_t in_len,
+                void             *out_data, size_t out_len);
 
 #endif
 
diff --git a/src/lzfP.h b/src/lzfP.h
index 78c858fad..567f5a201 100644
--- a/src/lzfP.h
+++ b/src/lzfP.h
@@ -129,8 +129,9 @@
  * Whether to store pointers or offsets inside the hash table. On
  * 64 bit architectures, pointers take up twice as much space,
  * and might also be slower. Default is to autodetect.
- */
-/*#define LZF_USER_OFFSETS autodetect */
+ * Notice: Don't set this value to 1, it will result in 'LZF_HSLOT'
+ * not being able to store offset above UINT32_MAX in 64bit. */
+#define LZF_USE_OFFSETS 0
 
 /*****************************************************************************/
 /* nothing should be changed below */
diff --git a/src/lzf_c.c b/src/lzf_c.c
index 6c117dab1..7cbbc82fa 100644
--- a/src/lzf_c.c
+++ b/src/lzf_c.c
@@ -105,9 +105,9 @@
  *
  */
 NO_SANITIZE("alignment")
-unsigned int
-lzf_compress (const void *const in_data, unsigned int in_len,
-	      void *out_data, unsigned int out_len
+size_t
+lzf_compress (const void *const in_data, size_t in_len,
+	      void *out_data, size_t out_len
 #if LZF_STATE_ARG
               , LZF_STATE htab
 #endif
@@ -132,7 +132,7 @@ lzf_compress (const void *const in_data, unsigned int in_len,
 #if defined (WIN32) && defined (_M_X64)
   unsigned _int64 off; /* workaround for missing POSIX compliance */
 #else
-  unsigned long off;
+  size_t off;
 #endif
   unsigned int hval;
   int lit;
@@ -153,7 +153,8 @@ lzf_compress (const void *const in_data, unsigned int in_len,
 
       hval = NEXT (hval, ip);
       hslot = htab + IDX (hval);
-      ref = *hslot + LZF_HSLOT_BIAS; *hslot = ip - LZF_HSLOT_BIAS;
+      ref = *hslot ? (*hslot + LZF_HSLOT_BIAS) : NULL; /* avoid applying zero offset to null pointer */
+      *hslot = ip - LZF_HSLOT_BIAS;
 
       if (1
 #if INIT_HTAB
@@ -171,7 +172,7 @@ lzf_compress (const void *const in_data, unsigned int in_len,
         {
           /* match found at *ref++ */
           unsigned int len = 2;
-          unsigned int maxlen = in_end - ip - len;
+          size_t maxlen = in_end - ip - len;
           maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
 
           if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
diff --git a/src/lzf_d.c b/src/lzf_d.c
index dbf1ae772..ff32be892 100644
--- a/src/lzf_d.c
+++ b/src/lzf_d.c
@@ -56,9 +56,9 @@
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
 #endif
-unsigned int
-lzf_decompress (const void *const in_data,  unsigned int in_len,
-                void             *out_data, unsigned int out_len)
+size_t
+lzf_decompress (const void *const in_data,  size_t in_len,
+                void             *out_data, size_t out_len)
 {
   u8 const *ip = (const u8 *)in_data;
   u8       *op = (u8 *)out_data;
diff --git a/src/quicklist.c b/src/quicklist.c
index b1051bd9b..22bd9b516 100644
--- a/src/quicklist.c
+++ b/src/quicklist.c
@@ -1721,6 +1721,7 @@ void quicklistBookmarksClear(quicklist *ql) {
 #include <stdint.h>
 #include <sys/time.h>
 #include "testhelp.h"
+#include <stdlib.h>
 
 #define yell(str, ...) printf("ERROR! " str "\n\n", __VA_ARGS__)
 
@@ -1902,6 +1903,30 @@ static char *genstr(char *prefix, int i) {
     return result;
 }
 
+static void randstring(unsigned char *target, size_t sz) {
+    size_t p = 0;
+    int minval, maxval;
+    switch(rand() % 3) {
+    case 0:
+        minval = 'a';
+        maxval = 'z';
+    break;
+    case 1:
+        minval = '0';
+        maxval = '9';
+    break;
+    case 2:
+        minval = 'A';
+        maxval = 'Z';
+    break;
+    default:
+        assert(NULL);
+    }
+
+    while(p < sz)
+        target[p++] = minval+rand()%(maxval-minval+1);
+}
+
 /* main test, but callable from other files */
 int quicklistTest(int argc, char *argv[], int flags) {
     UNUSED(argc);
@@ -3125,6 +3150,57 @@ int quicklistTest(int argc, char *argv[], int flags) {
         quicklistRelease(ql);
     }
 
+    if (flags & REDIS_TEST_LARGE_MEMORY) {
+        TEST("compress and decompress quicklist ziplist node") {
+            quicklistNode *node = quicklistCreateNode();
+            node->entry = ziplistNew();
+            
+            /* Create a rand string */
+            size_t sz = (1 << 25); /* 32MB per one entry */
+            unsigned char *s = zmalloc(sz);
+            randstring(s, sz);
+
+            /* Keep filling the node, until it reaches 1GB */
+            for (int i = 0; i < 32; i++) {
+                node->entry = ziplistPush(node->entry, s, sz, ZIPLIST_TAIL);
+                quicklistNodeUpdateSz(node);
+
+                long long start = mstime();
+                assert(__quicklistCompressNode(node));
+                assert(__quicklistDecompressNode(node));
+                printf("Compress and decompress: %zu MB in %.2f seconds.\n",
+                       node->sz/1024/1024, (float)(mstime() - start) / 1000);
+            }
+
+            zfree(s);
+            zfree(node->entry);
+            zfree(node);
+        }
+
+#if ULONG_MAX >= 0xffffffffffffffff
+        TEST("compress and decomress quicklist plain node large than UINT32_MAX") {
+            size_t sz = (1ull << 32);
+            unsigned char *s = zmalloc(sz);
+            randstring(s, sz);
+            memcpy(s, "helloworld", 10);
+            memcpy(s + sz - 10, "1234567890", 10);
+
+            quicklistNode *node = __quicklistCreatePlainNode(s, sz);
+
+            long long start = mstime();
+            assert(__quicklistCompressNode(node));
+            assert(__quicklistDecompressNode(node));
+            printf("Compress and decompress: %zu MB in %.2f seconds.\n",
+                   node->sz/1024/1024, (float)(mstime() - start) / 1000);
+
+            assert(memcmp(node->entry, "helloworld", 10) == 0);
+            assert(memcmp(node->entry + sz - 10, "1234567890", 10) == 0);
+            zfree(node->entry);
+            zfree(node);
+        }
+#endif
+    }
+
     if (!err)
         printf("ALL TESTS PASSED!\n");
     else
diff --git a/tests/unit/bitops.tcl b/tests/unit/bitops.tcl
index 1a3c3a54e..89431c81f 100644
--- a/tests/unit/bitops.tcl
+++ b/tests/unit/bitops.tcl
@@ -566,4 +566,18 @@ start_server {tags {"bitops"}} {
         r config set proto-max-bulk-len $oldval
         r del mykey
     } {1} {large-memory}
+
+    test "SETBIT values larger than UINT32_MAX and lzf_compress/lzf_decompress correctly" {
+        set bytes [expr (1 << 32) + 1]
+        set bitpos [expr (1 << 35)]
+        set oldval [lindex [r config get proto-max-bulk-len] 1]
+        r config set proto-max-bulk-len $bytes
+        r setbit mykey $bitpos 1
+        assert_equal $bytes [r strlen mykey]
+        assert_equal 1 [r getbit mykey $bitpos]
+        r debug reload ;# lzf_compress/lzf_decompress when RDB saving/loading.
+        assert_equal 1 [r getbit mykey $bitpos]
+        r config set proto-max-bulk-len $oldval
+        r del mykey
+    } {1} {large-memory needs:debug}
 }