Fixed issue with trailing dots in file paths

Paths such as the following were causing issues:
/tea/hottea/.
/tea/hottea/..

Unfortunately the existing structure for path lookup didn't make it very
easy to introduce proper handling in this case without duplicating the
entire skip logic for paths. So the lfs_dir_find function had to be
restructured a bit.

One odd side-effect of this is that now lfs_dir_find includes the
initial fetch operation. This kinda breaks the fetch -> op pattern of
the dir functions, but does come with a nice code size reduction.

.travis.yml

@@ -1,107 +1,224 @@
+# Environment variables
 env:
+  global:
     - CFLAGS=-Werror
 
+# Common test script
 script:
-    # make sure example can at least compile
-    - sed -n '/``` c/,/```/{/```/d; p;}' README.md > test.c &&
-      make all size CFLAGS+="
+  # make sure example can at least compile
+  - sed -n '/``` c/,/```/{/```/d; p;}' README.md > test.c &&
+    make all CFLAGS+="
         -Duser_provided_block_device_read=NULL
         -Duser_provided_block_device_prog=NULL
         -Duser_provided_block_device_erase=NULL
         -Duser_provided_block_device_sync=NULL
         -include stdio.h"
 
-    # run tests
-    - make test QUIET=1
+  # run tests
+  - make test QUIET=1
 
-    # run tests with a few different configurations
-    - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=1      -DLFS_PROG_SIZE=1"
-    - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=512    -DLFS_PROG_SIZE=512"
-    - make test QUIET=1 CFLAGS+="-DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD=2048"
+  # run tests with a few different configurations
+  - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=1      -DLFS_PROG_SIZE=1"
+  - make test QUIET=1 CFLAGS+="-DLFS_READ_SIZE=512    -DLFS_PROG_SIZE=512"
+  - make test QUIET=1 CFLAGS+="-DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD=2048"
+
+  - make clean test QUIET=1 CFLAGS+="-DLFS_NO_INTRINSICS"
+
+  # compile and find the code size with the smallest configuration
+  - make clean size
+        OBJ="$(ls lfs*.o | tr '\n' ' ')"
+        CFLAGS+="-DLFS_NO{ASSERT,DEBUG,WARN,ERROR}"
+        | tee sizes
+
+  # update status if we succeeded, compare with master if possible
+  - |
+    if [ "$TRAVIS_TEST_RESULT" -eq 0 ]
+    then
+        CURR=$(tail -n1 sizes | awk '{print $1}')
+        PREV=$(curl -u $GEKY_BOT_STATUSES https://api.github.com/repos/$TRAVIS_REPO_SLUG/status/master \
+            | jq -re "select(.sha != \"$TRAVIS_COMMIT\")
+                | .statuses[] | select(.context == \"$STAGE/$NAME\").description
+                | capture(\"code size is (?<size>[0-9]+)\").size" \
+            || echo 0)
+
+        STATUS="Passed, code size is ${CURR}B"
+        if [ "$PREV" -ne 0 ]
+        then
+            STATUS="$STATUS ($(python -c "print '%+.2f' % (100*($CURR-$PREV)/$PREV.0)")%)"
+        fi
+    fi
+
+# CI matrix
+jobs:
+  include:
+    # native testing
+    - stage: test
+      env:
+        - STAGE=test
+        - NAME=littlefs-x86
+
+    # cross-compile with ARM (thumb mode)
+    - stage: test
+      env:
+        - STAGE=test
+        - NAME=littlefs-arm
+        - CC="arm-linux-gnueabi-gcc --static -mthumb"
+        - EXEC="qemu-arm"
+      install:
+        - sudo apt-get install gcc-arm-linux-gnueabi qemu-user
+        - arm-linux-gnueabi-gcc --version
+        - qemu-arm -version
+
+    # cross-compile with PowerPC
+    - stage: test
+      env:
+        - STAGE=test
+        - NAME=littlefs-powerpc
+        - CC="powerpc-linux-gnu-gcc --static"
+        - EXEC="qemu-ppc"
+      install:
+        - sudo apt-get install gcc-powerpc-linux-gnu qemu-user
+        - powerpc-linux-gnu-gcc --version
+        - qemu-ppc -version
+
+    # cross-compile with MIPS
+    - stage: test
+      env:
+        - STAGE=test
+        - NAME=littlefs-mips
+        - CC="mips-linux-gnu-gcc --static"
+        - EXEC="qemu-mips"
+      install:
+        - sudo add-apt-repository -y "deb http://archive.ubuntu.com/ubuntu/ xenial main universe"
+        - sudo apt-get -qq update
+        - sudo apt-get install gcc-mips-linux-gnu qemu-user
+        - mips-linux-gnu-gcc --version
+        - qemu-mips -version
 
     # self-host with littlefs-fuse for fuzz test
-    - make -C littlefs-fuse
+    - stage: test
+      env:
+        - STAGE=test
+        - NAME=littlefs-fuse
+      install:
+        - sudo apt-get install libfuse-dev
+        - git clone --depth 1 https://github.com/geky/littlefs-fuse
+        - fusermount -V
+        - gcc --version
+      before_script:
+        # setup disk for littlefs-fuse
+        - rm -rf littlefs-fuse/littlefs/*
+        - cp -r $(git ls-tree --name-only HEAD) littlefs-fuse/littlefs
 
-    - littlefs-fuse/lfs --format /dev/loop0
-    - littlefs-fuse/lfs /dev/loop0 mount
+        - mkdir mount
+        - sudo chmod a+rw /dev/loop0
+        - dd if=/dev/zero bs=512 count=2048 of=disk
+        - losetup /dev/loop0 disk
+      script:
+        # self-host test
+        - make -C littlefs-fuse
 
-    - ls mount
-    - mkdir mount/littlefs
-    - cp -r $(git ls-tree --name-only HEAD) mount/littlefs
-    - cd mount/littlefs
-    - ls
-    - make -B test_dirs test_files QUIET=1
+        - littlefs-fuse/lfs --format /dev/loop0
+        - littlefs-fuse/lfs /dev/loop0 mount
 
-before_install:
-    - fusermount -V
-    - gcc --version
+        - ls mount
+        - mkdir mount/littlefs
+        - cp -r $(git ls-tree --name-only HEAD) mount/littlefs
+        - cd mount/littlefs
+        - ls
+        - make -B test_dirs test_files QUIET=1
 
-install:
-    - sudo apt-get install libfuse-dev
-    - git clone --depth 1 https://github.com/geky/littlefs-fuse
-
-before_script:
-    - rm -rf littlefs-fuse/littlefs/*
-    - cp -r $(git ls-tree --name-only HEAD) littlefs-fuse/littlefs
-
-    - mkdir mount
-    - sudo chmod a+rw /dev/loop0
-    - dd if=/dev/zero bs=512 count=2048 of=disk
-    - losetup /dev/loop0 disk
-
-deploy:
-    # Let before_deploy take over
-    provider: script
-    script: 'true'
-    on:
-        branch: master
-
-before_deploy:
-    - cd $TRAVIS_BUILD_DIR
-    # Update tag for version defined in lfs.h
-    - LFS_VERSION=$(grep -ox '#define LFS_VERSION .*' lfs.h | cut -d ' ' -f3)
-    - LFS_VERSION_MAJOR=$((0xffff & ($LFS_VERSION >> 16)))
-    - LFS_VERSION_MINOR=$((0xffff & ($LFS_VERSION >>  0)))
-    - LFS_VERSION="v$LFS_VERSION_MAJOR.$LFS_VERSION_MINOR"
-    - echo "littlefs version $LFS_VERSION"
-    - |
-      curl -u $GEKY_BOT -X POST \
-        https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs \
-        -d "{
-          \"ref\": \"refs/tags/$LFS_VERSION\",
-          \"sha\": \"$TRAVIS_COMMIT\"
-        }"
-    - |
-      curl -f -u $GEKY_BOT -X PATCH \
-        https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs/tags/$LFS_VERSION \
-        -d "{
-          \"sha\": \"$TRAVIS_COMMIT\"
-        }"
-    # Create release notes from commits
-    - LFS_PREV_VERSION="v$LFS_VERSION_MAJOR.$(($LFS_VERSION_MINOR-1))"
-    - |
-      if [ $(git tag -l "$LFS_PREV_VERSION") ]
-      then
-        curl -u $GEKY_BOT -X POST \
-            https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases \
+      # Automatically update releases
+    - stage: deploy
+      env:
+        - STAGE=deploy
+        - NAME=deploy
+      script:
+        # Update tag for version defined in lfs.h
+        - LFS_VERSION=$(grep -ox '#define LFS_VERSION .*' lfs.h | cut -d ' ' -f3)
+        - LFS_VERSION_MAJOR=$((0xffff & ($LFS_VERSION >> 16)))
+        - LFS_VERSION_MINOR=$((0xffff & ($LFS_VERSION >>  0)))
+        - LFS_VERSION="v$LFS_VERSION_MAJOR.$LFS_VERSION_MINOR"
+        - echo "littlefs version $LFS_VERSION"
+        - |
+          curl -u $GEKY_BOT_RELEASES -X POST \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs \
             -d "{
-                \"tag_name\": \"$LFS_VERSION\",
-                \"name\": \"$LFS_VERSION\"
+              \"ref\": \"refs/tags/$LFS_VERSION\",
+              \"sha\": \"$TRAVIS_COMMIT\"
             }"
-        RELEASE=$(
-            curl -f https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases/tags/$LFS_VERSION
-        )
-        CHANGES=$(
-            git log --oneline $LFS_PREV_VERSION.. --grep='^Merge' --invert-grep
-        )
-        curl -f -u $GEKY_BOT -X PATCH \
-            https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases/$(
-                jq -r '.id' <<< "$RELEASE"
-            ) \
-            -d "$(
-                jq -s '{
-                    "body": ((.[0] // "" | sub("(?<=\n)#+ Changes.*"; ""; "mi"))
-                        + "### Changes\n\n" + .[1])
-                }' <(jq '.body' <<< "$RELEASE") <(jq -sR '.' <<< "$CHANGES")
-            )"
-      fi
+        - |
+          curl -f -u $GEKY_BOT_RELEASES -X PATCH \
+            https://api.github.com/repos/$TRAVIS_REPO_SLUG/git/refs/tags/$LFS_VERSION \
+            -d "{
+              \"sha\": \"$TRAVIS_COMMIT\"
+            }"
+        # Create release notes from commits
+        - LFS_PREV_VERSION="v$LFS_VERSION_MAJOR.$(($LFS_VERSION_MINOR-1))"
+        - |
+          if [ $(git tag -l "$LFS_PREV_VERSION") ]
+          then
+            curl -u $GEKY_BOT_RELEASES -X POST \
+                https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases \
+                -d "{
+                    \"tag_name\": \"$LFS_VERSION\",
+                    \"name\": \"$LFS_VERSION\"
+                }"
+            RELEASE=$(
+                curl -f -u $GEKY_BOT_RELEASES \
+                    https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases/tags/$LFS_VERSION
+            )
+            CHANGES=$(
+                git log --oneline $LFS_PREV_VERSION.. --grep='^Merge' --invert-grep
+            )
+            curl -f -u $GEKY_BOT_RELEASES -X PATCH \
+                https://api.github.com/repos/$TRAVIS_REPO_SLUG/releases/$(
+                    jq -r '.id' <<< "$RELEASE"
+                ) \
+                -d "$(
+                    jq -s '{
+                        "body": ((.[0] // "" | sub("(?<=\n)#+ Changes.*"; ""; "mi"))
+                            + "### Changes\n\n" + .[1])
+                    }' <(jq '.body' <<< "$RELEASE") <(jq -sR '.' <<< "$CHANGES")
+                )"
+          fi
+
+# Manage statuses
+before_install:
+  - |
+    curl -u $GEKY_BOT_STATUSES -X POST \
+        https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+        -d "{
+            \"context\": \"$STAGE/$NAME\",
+            \"state\": \"pending\",
+            \"description\": \"${STATUS:-In progress}\",
+            \"target_url\": \"https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$TRAVIS_JOB_ID\"
+        }"
+
+after_failure:
+  - |
+    curl -u $GEKY_BOT_STATUSES -X POST \
+        https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+        -d "{
+            \"context\": \"$STAGE/$NAME\",
+            \"state\": \"failure\",
+            \"description\": \"${STATUS:-Failed}\",
+            \"target_url\": \"https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$TRAVIS_JOB_ID\"
+        }"
+
+after_success:
+  - |
+    curl -u $GEKY_BOT_STATUSES -X POST \
+        https://api.github.com/repos/$TRAVIS_REPO_SLUG/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT} \
+        -d "{
+            \"context\": \"$STAGE/$NAME\",
+            \"state\": \"success\",
+            \"description\": \"${STATUS:-Passed}\",
+            \"target_url\": \"https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$TRAVIS_JOB_ID\"
+        }"
+
+# Job control
+stages:
+    - name: test
+    - name: deploy
+      if: branch = master AND type = push

Makefile

@@ -1,8 +1,8 @@
 TARGET = lfs
 
-CC = gcc
-AR = ar
-SIZE = size
+CC ?= gcc
+AR ?= ar
+SIZE ?= size
 
 SRC += $(wildcard *.c emubd/*.c)
 OBJ := $(SRC:.c=.o)
@@ -33,8 +33,8 @@ size: $(OBJ)
 	$(SIZE) -t $^
 
 .SUFFIXES:
-test: test_format test_dirs test_files test_seek test_truncate test_parallel \
-	test_alloc test_paths test_orphan test_move test_corrupt
+test: test_format test_dirs test_files test_seek test_truncate \
+	test_interspersed test_alloc test_paths test_orphan test_move test_corrupt
 test_%: tests/test_%.sh
 ifdef QUIET
 	@./$< | sed -n '/^[-=]/p'

README.md

@@ -115,10 +115,17 @@ All littlefs have the potential to return a negative error code. The errors
 can be either one of those found in the `enum lfs_error` in [lfs.h](lfs.h),
 or an error returned by the user's block device operations.
 
-It should also be noted that the current implementation of littlefs doesn't
-really do anything to ensure that the data written to disk is machine portable.
-This is fine as long as all of the involved machines share endianness
-(little-endian) and don't have strange padding requirements.
+In the configuration struct, the `prog` and `erase` function provided by the
+user may return a `LFS_ERR_CORRUPT` error if the implementation already can
+detect corrupt blocks. However, the wear leveling does not depend on the return
+code of these functions, instead all data is read back and checked for
+integrity.
+
+If your storage caches writes, make sure that the provided `sync` function
+flushes all the data to memory and ensures that the next read fetches the data
+from memory, otherwise data integrity can not be guaranteed. If the `write`
+function does not perform caching, and therefore each `read` or `write` call
+hits the memory, the `sync` function can simply return 0.
 
 ## Reference material
 

lfs.c

@@ -18,17 +18,13 @@
 #include "lfs.h"
 #include "lfs_util.h"
 
-#include <string.h>
-#include <stdlib.h>
-#include <assert.h>
-
 
 /// Caching block device operations ///
 static int lfs_cache_read(lfs_t *lfs, lfs_cache_t *rcache,
         const lfs_cache_t *pcache, lfs_block_t block,
         lfs_off_t off, void *buffer, lfs_size_t size) {
     uint8_t *data = buffer;
-    assert(block < lfs->cfg->block_count);
+    LFS_ASSERT(block < lfs->cfg->block_count);
 
     while (size > 0) {
         if (pcache && block == pcache->block && off >= pcache->off &&
@@ -153,7 +149,7 @@ static int lfs_cache_prog(lfs_t *lfs, lfs_cache_t *pcache,
         lfs_cache_t *rcache, lfs_block_t block,
         lfs_off_t off, const void *buffer, lfs_size_t size) {
     const uint8_t *data = buffer;
-    assert(block < lfs->cfg->block_count);
+    LFS_ASSERT(block < lfs->cfg->block_count);
 
     while (size > 0) {
         if (block == pcache->block && off >= pcache->off &&
@@ -180,7 +176,7 @@ static int lfs_cache_prog(lfs_t *lfs, lfs_cache_t *pcache,
 
         // pcache must have been flushed, either by programming and
         // entire block or manually flushing the pcache
-        assert(pcache->block == 0xffffffff);
+        LFS_ASSERT(pcache->block == 0xffffffff);
 
         if (off % lfs->cfg->prog_size == 0 &&
                 size >= lfs->cfg->prog_size) {
@@ -274,8 +270,7 @@ int lfs_deorphan(lfs_t *lfs);
 static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
     lfs_t *lfs = p;
 
-    lfs_block_t off = (((lfs_soff_t)(block - lfs->free.begin)
-                % (lfs_soff_t)(lfs->cfg->block_count))
+    lfs_block_t off = ((block - lfs->free.off)
             + lfs->cfg->block_count) % lfs->cfg->block_count;
 
     if (off < lfs->free.size) {
@@ -287,27 +282,38 @@ static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
 
 static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
     while (true) {
-        while (lfs->free.off != lfs->free.size) {
-            lfs_block_t off = lfs->free.off;
-            lfs->free.off += 1;
+        while (lfs->free.i != lfs->free.size) {
+            lfs_block_t off = lfs->free.i;
+            lfs->free.i += 1;
+            lfs->free.ack -= 1;
 
             if (!(lfs->free.buffer[off / 32] & (1U << (off % 32)))) {
                 // found a free block
-                *block = (lfs->free.begin + off) % lfs->cfg->block_count;
+                *block = (lfs->free.off + off) % lfs->cfg->block_count;
+
+                // eagerly find next off so an alloc ack can
+                // discredit old lookahead blocks
+                while (lfs->free.i != lfs->free.size &&
+                        (lfs->free.buffer[lfs->free.i / 32]
+                            & (1U << (lfs->free.i % 32)))) {
+                    lfs->free.i += 1;
+                    lfs->free.ack -= 1;
+                }
+
                 return 0;
             }
         }
 
         // check if we have looked at all blocks since last ack
-        if (lfs->free.off == lfs->free.ack - lfs->free.begin) {
-            LFS_WARN("No more free space %d", lfs->free.off + lfs->free.begin);
+        if (lfs->free.ack == 0) {
+            LFS_WARN("No more free space %d", lfs->free.i + lfs->free.off);
             return LFS_ERR_NOSPC;
         }
 
-        lfs->free.begin += lfs->free.size;
-        lfs->free.size = lfs_min(lfs->cfg->lookahead,
-                lfs->free.ack - lfs->free.begin);
-        lfs->free.off = 0;
+        lfs->free.off = (lfs->free.off + lfs->free.size)
+                % lfs->cfg->block_count;
+        lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->free.ack);
+        lfs->free.i = 0;
 
         // find mask of free blocks from tree
         memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
@@ -319,7 +325,49 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
 }
 
 static void lfs_alloc_ack(lfs_t *lfs) {
-    lfs->free.ack = lfs->free.off-1 + lfs->free.begin + lfs->cfg->block_count;
+    lfs->free.ack = lfs->cfg->block_count;
+}
+
+
+/// Endian swapping functions ///
+static void lfs_dir_fromle32(struct lfs_disk_dir *d) {
+    d->rev     = lfs_fromle32(d->rev);
+    d->size    = lfs_fromle32(d->size);
+    d->tail[0] = lfs_fromle32(d->tail[0]);
+    d->tail[1] = lfs_fromle32(d->tail[1]);
+}
+
+static void lfs_dir_tole32(struct lfs_disk_dir *d) {
+    d->rev     = lfs_tole32(d->rev);
+    d->size    = lfs_tole32(d->size);
+    d->tail[0] = lfs_tole32(d->tail[0]);
+    d->tail[1] = lfs_tole32(d->tail[1]);
+}
+
+static void lfs_entry_fromle32(struct lfs_disk_entry *d) {
+    d->u.dir[0] = lfs_fromle32(d->u.dir[0]);
+    d->u.dir[1] = lfs_fromle32(d->u.dir[1]);
+}
+
+static void lfs_entry_tole32(struct lfs_disk_entry *d) {
+    d->u.dir[0] = lfs_tole32(d->u.dir[0]);
+    d->u.dir[1] = lfs_tole32(d->u.dir[1]);
+}
+
+static void lfs_superblock_fromle32(struct lfs_disk_superblock *d) {
+    d->root[0]     = lfs_fromle32(d->root[0]);
+    d->root[1]     = lfs_fromle32(d->root[1]);
+    d->block_size  = lfs_fromle32(d->block_size);
+    d->block_count = lfs_fromle32(d->block_count);
+    d->version     = lfs_fromle32(d->version);
+}
+
+static void lfs_superblock_tole32(struct lfs_disk_superblock *d) {
+    d->root[0]     = lfs_tole32(d->root[0]);
+    d->root[1]     = lfs_tole32(d->root[1]);
+    d->block_size  = lfs_tole32(d->block_size);
+    d->block_count = lfs_tole32(d->block_count);
+    d->version     = lfs_tole32(d->version);
 }
 
 
@@ -364,6 +412,7 @@ static int lfs_dir_alloc(lfs_t *lfs, lfs_dir_t *dir) {
     // rather than clobbering one of the blocks we just pretend
     // the revision may be valid
     int err = lfs_bd_read(lfs, dir->pair[0], 0, &dir->d.rev, 4);
+    dir->d.rev = lfs_fromle32(dir->d.rev);
     if (err) {
         return err;
     }
@@ -389,6 +438,7 @@ static int lfs_dir_fetch(lfs_t *lfs,
     for (int i = 0; i < 2; i++) {
         struct lfs_disk_dir test;
         int err = lfs_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
+        lfs_dir_fromle32(&test);
         if (err) {
             return err;
         }
@@ -403,7 +453,9 @@ static int lfs_dir_fetch(lfs_t *lfs,
         }
 
         uint32_t crc = 0xffffffff;
+        lfs_dir_tole32(&test);
         lfs_crc(&crc, &test, sizeof(test));
+        lfs_dir_fromle32(&test);
         err = lfs_bd_crc(lfs, tpair[i], sizeof(test),
                 (0x7fffffff & test.size) - sizeof(test), &crc);
         if (err) {
@@ -463,8 +515,10 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
             }
 
             uint32_t crc = 0xffffffff;
+            lfs_dir_tole32(&dir->d);
             lfs_crc(&crc, &dir->d, sizeof(dir->d));
             err = lfs_bd_prog(lfs, dir->pair[0], 0, &dir->d, sizeof(dir->d));
+            lfs_dir_fromle32(&dir->d);
             if (err) {
                 if (err == LFS_ERR_CORRUPT) {
                     goto relocate;
@@ -511,7 +565,9 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
                 }
             }
 
+            crc = lfs_tole32(crc);
             err = lfs_bd_prog(lfs, dir->pair[0], newoff, &crc, 4);
+            crc = lfs_fromle32(crc);
             if (err) {
                 if (err == LFS_ERR_CORRUPT) {
                     goto relocate;
@@ -584,11 +640,14 @@ relocate:
 }
 
 static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
-        const lfs_entry_t *entry, const void *data) {
-    return lfs_dir_commit(lfs, dir, (struct lfs_region[]){
+        lfs_entry_t *entry, const void *data) {
+    lfs_entry_tole32(&entry->d);
+    int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
             {entry->off, sizeof(entry->d), &entry->d, sizeof(entry->d)},
             {entry->off+sizeof(entry->d), entry->d.nlen, data, entry->d.nlen}
         }, data ? 2 : 1);
+    lfs_entry_fromle32(&entry->d);
+    return err;
 }
 
 static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
@@ -597,35 +656,41 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
     while (true) {
         if (dir->d.size + lfs_entry_size(entry) <= lfs->cfg->block_size) {
             entry->off = dir->d.size - 4;
-            return lfs_dir_commit(lfs, dir, (struct lfs_region[]){
+
+            lfs_entry_tole32(&entry->d);
+            int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
                     {entry->off, 0, &entry->d, sizeof(entry->d)},
                     {entry->off, 0, data, entry->d.nlen}
                 }, 2);
+            lfs_entry_fromle32(&entry->d);
+            return err;
         }
 
         // we need to allocate a new dir block
         if (!(0x80000000 & dir->d.size)) {
-            lfs_dir_t newdir;
-            int err = lfs_dir_alloc(lfs, &newdir);
+            lfs_dir_t olddir = *dir;
+            int err = lfs_dir_alloc(lfs, dir);
             if (err) {
                 return err;
             }
 
-            newdir.d.tail[0] = dir->d.tail[0];
-            newdir.d.tail[1] = dir->d.tail[1];
-            entry->off = newdir.d.size - 4;
-            err = lfs_dir_commit(lfs, &newdir, (struct lfs_region[]){
+            dir->d.tail[0] = olddir.d.tail[0];
+            dir->d.tail[1] = olddir.d.tail[1];
+            entry->off = dir->d.size - 4;
+            lfs_entry_tole32(&entry->d);
+            err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
                     {entry->off, 0, &entry->d, sizeof(entry->d)},
                     {entry->off, 0, data, entry->d.nlen}
                 }, 2);
+            lfs_entry_fromle32(&entry->d);
             if (err) {
                 return err;
             }
 
-            dir->d.size |= 0x80000000;
-            dir->d.tail[0] = newdir.pair[0];
-            dir->d.tail[1] = newdir.pair[1];
-            return lfs_dir_commit(lfs, dir, NULL, 0);
+            olddir.d.size |= 0x80000000;
+            olddir.d.tail[0] = dir->pair[0];
+            olddir.d.tail[1] = dir->pair[1];
+            return lfs_dir_commit(lfs, &olddir, NULL, 0);
         }
 
         int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
@@ -703,6 +768,7 @@ static int lfs_dir_next(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
 
     int err = lfs_bd_read(lfs, dir->pair[0], dir->off,
             &entry->d, sizeof(entry->d));
+    lfs_entry_fromle32(&entry->d);
     if (err) {
         return err;
     }
@@ -717,9 +783,15 @@ static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
         lfs_entry_t *entry, const char **path) {
     const char *pathname = *path;
     size_t pathlen;
+    entry->d.type = LFS_TYPE_DIR;
+    entry->d.elen = sizeof(entry->d) - 4;
+    entry->d.alen = 0;
+    entry->d.nlen = 0;
+    entry->d.u.dir[0] = lfs->root[0];
+    entry->d.u.dir[1] = lfs->root[1];
 
     while (true) {
-    nextname:
+nextname:
         // skip slashes
         pathname += strspn(pathname, "/");
         pathlen = strcspn(pathname, "/");
@@ -755,10 +827,25 @@ static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
             suffix += sufflen;
         }
 
+        // found path
+        if (pathname[0] == '\0') {
+            return 0;
+        }
+
         // update what we've found
         *path = pathname;
 
-        // find path
+        // continue on if we hit a directory
+        if (entry->d.type != LFS_TYPE_DIR) {
+            return LFS_ERR_NOTDIR;
+        }
+
+        int err = lfs_dir_fetch(lfs, dir, entry->d.u.dir);
+        if (err) {
+            return err;
+        }
+
+        // find entry matching name
         while (true) {
             int err = lfs_dir_next(lfs, dir, entry);
             if (err) {
@@ -794,21 +881,8 @@ static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
             entry->d.type &= ~0x80;
         }
 
+        // to next name
         pathname += pathlen;
-        pathname += strspn(pathname, "/");
-        if (pathname[0] == '\0') {
-            return 0;
-        }
-
-        // continue on if we hit a directory
-        if (entry->d.type != LFS_TYPE_DIR) {
-            return LFS_ERR_NOTDIR;
-        }
-
-        int err = lfs_dir_fetch(lfs, dir, entry->d.u.dir);
-        if (err) {
-            return err;
-        }
     }
 }
 
@@ -825,13 +899,8 @@ int lfs_mkdir(lfs_t *lfs, const char *path) {
 
     // fetch parent directory
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err != LFS_ERR_NOENT || strchr(path, '/') != NULL) {
         return err ? err : LFS_ERR_EXIST;
     }
@@ -875,22 +944,8 @@ int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
     dir->pair[0] = lfs->root[0];
     dir->pair[1] = lfs->root[1];
 
-    int err = lfs_dir_fetch(lfs, dir, dir->pair);
-    if (err) {
-        return err;
-    }
-
-    // check for root, can only be something like '/././../.'
-    if (strspn(path, "/.") == strlen(path)) {
-        dir->head[0] = dir->pair[0];
-        dir->head[1] = dir->pair[1];
-        dir->pos = sizeof(dir->d) - 2;
-        dir->off = sizeof(dir->d);
-        return 0;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, dir, &entry, &path);
+    int err = lfs_dir_find(lfs, dir, &entry, &path);
     if (err) {
         return err;
     } else if (entry.d.type != LFS_TYPE_DIR) {
@@ -1065,11 +1120,12 @@ static int lfs_ctz_find(lfs_t *lfs,
                 lfs_ctz(current));
 
         int err = lfs_cache_read(lfs, rcache, pcache, head, 4*skip, &head, 4);
+        head = lfs_fromle32(head);
         if (err) {
             return err;
         }
 
-        assert(head >= 2 && head <= lfs->cfg->block_count);
+        LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
         current -= 1 << skip;
     }
 
@@ -1089,7 +1145,7 @@ static int lfs_ctz_extend(lfs_t *lfs,
         if (err) {
             return err;
         }
-        assert(nblock >= 2 && nblock <= lfs->cfg->block_count);
+        LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
 
         if (true) {
             err = lfs_bd_erase(lfs, nblock);
@@ -1140,8 +1196,10 @@ static int lfs_ctz_extend(lfs_t *lfs,
             lfs_size_t skips = lfs_ctz(index) + 1;
 
             for (lfs_off_t i = 0; i < skips; i++) {
+                head = lfs_tole32(head);
                 err = lfs_cache_prog(lfs, pcache, rcache,
                         nblock, 4*i, &head, 4);
+                head = lfs_fromle32(head);
                 if (err) {
                     if (err == LFS_ERR_CORRUPT) {
                         goto relocate;
@@ -1152,12 +1210,13 @@ static int lfs_ctz_extend(lfs_t *lfs,
                 if (i != skips-1) {
                     err = lfs_cache_read(lfs, rcache, NULL,
                             head, 4*i, &head, 4);
+                    head = lfs_fromle32(head);
                     if (err) {
                         return err;
                     }
                 }
 
-                assert(head >= 2 && head <= lfs->cfg->block_count);
+                LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
             }
 
             *block = nblock;
@@ -1196,6 +1255,8 @@ static int lfs_ctz_traverse(lfs_t *lfs,
         lfs_block_t heads[2];
         int count = 2 - (index & 1);
         err = lfs_cache_read(lfs, rcache, pcache, head, 0, &heads, count*4);
+        heads[0] = lfs_fromle32(heads[0]);
+        heads[1] = lfs_fromle32(heads[1]);
         if (err) {
             return err;
         }
@@ -1226,13 +1287,8 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
 
     // allocate entry for file if it doesn't exist
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err && (err != LFS_ERR_NOENT || strchr(path, '/') != NULL)) {
         return err;
     }
@@ -1281,12 +1337,12 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
     if (lfs->cfg->file_buffer) {
         file->cache.buffer = lfs->cfg->file_buffer;
     } else if ((file->flags & 3) == LFS_O_RDONLY) {
-        file->cache.buffer = malloc(lfs->cfg->read_size);
+        file->cache.buffer = lfs_malloc(lfs->cfg->read_size);
         if (!file->cache.buffer) {
             return LFS_ERR_NOMEM;
         }
     } else {
-        file->cache.buffer = malloc(lfs->cfg->prog_size);
+        file->cache.buffer = lfs_malloc(lfs->cfg->prog_size);
         if (!file->cache.buffer) {
             return LFS_ERR_NOMEM;
         }
@@ -1312,7 +1368,7 @@ int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
 
     // clean up memory
     if (!lfs->cfg->file_buffer) {
-        free(file->cache.buffer);
+        lfs_free(file->cache.buffer);
     }
 
     return err;
@@ -1456,11 +1512,12 @@ int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
         lfs_entry_t entry = {.off = file->poff};
         err = lfs_bd_read(lfs, cwd.pair[0], entry.off,
                 &entry.d, sizeof(entry.d));
+        lfs_entry_fromle32(&entry.d);
         if (err) {
             return err;
         }
 
-        assert(entry.d.type == LFS_TYPE_REG);
+        LFS_ASSERT(entry.d.type == LFS_TYPE_REG);
         entry.d.u.file.head = file->head;
         entry.d.u.file.size = file->size;
 
@@ -1686,7 +1743,7 @@ int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
 
         // flush+seek if not already at end
         if (file->pos != oldsize) {
-            int err = lfs_file_seek(lfs, file, 0, SEEK_END);
+            int err = lfs_file_seek(lfs, file, 0, LFS_SEEK_END);
             if (err < 0) {
                 return err;
             }
@@ -1736,22 +1793,9 @@ lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
 
 /// General fs operations ///
 int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
-    // check for root, can only be something like '/././../.'
-    if (strspn(path, "/.") == strlen(path)) {
-        memset(info, 0, sizeof(*info));
-        info->type = LFS_TYPE_DIR;
-        strcpy(info->name, "/");
-        return 0;
-    }
-
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err) {
         return err;
     }
@@ -1762,11 +1806,15 @@ int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
         info->size = entry.d.u.file.size;
     }
 
-    err = lfs_bd_read(lfs, cwd.pair[0],
-            entry.off + 4+entry.d.elen+entry.d.alen,
-            info->name, entry.d.nlen);
-    if (err) {
-        return err;
+    if (lfs_paircmp(entry.d.u.dir, lfs->root) == 0) {
+        strcpy(info->name, "/");
+    } else {
+        err = lfs_bd_read(lfs, cwd.pair[0],
+                entry.off + 4+entry.d.elen+entry.d.alen,
+                info->name, entry.d.nlen);
+        if (err) {
+            return err;
+        }
     }
 
     return 0;
@@ -1782,13 +1830,8 @@ int lfs_remove(lfs_t *lfs, const char *path) {
     }
 
     lfs_dir_t cwd;
-    int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t entry;
-    err = lfs_dir_find(lfs, &cwd, &entry, &path);
+    int err = lfs_dir_find(lfs, &cwd, &entry, &path);
     if (err) {
         return err;
     }
@@ -1819,7 +1862,7 @@ int lfs_remove(lfs_t *lfs, const char *path) {
             return res;
         }
 
-        assert(res); // must have pred
+        LFS_ASSERT(res); // must have pred
         cwd.d.tail[0] = dir.d.tail[0];
         cwd.d.tail[1] = dir.d.tail[1];
 
@@ -1843,24 +1886,14 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
 
     // find old entry
     lfs_dir_t oldcwd;
-    int err = lfs_dir_fetch(lfs, &oldcwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t oldentry;
-    err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
+    int err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
     if (err) {
         return err;
     }
 
     // allocate new entry
     lfs_dir_t newcwd;
-    err = lfs_dir_fetch(lfs, &newcwd, lfs->root);
-    if (err) {
-        return err;
-    }
-
     lfs_entry_t preventry;
     err = lfs_dir_find(lfs, &newcwd, &preventry, &newpath);
     if (err && (err != LFS_ERR_NOENT || strchr(newpath, '/') != NULL)) {
@@ -1936,7 +1969,7 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
             return res;
         }
 
-        assert(res); // must have pred
+        LFS_ASSERT(res); // must have pred
         newcwd.d.tail[0] = dir.d.tail[0];
         newcwd.d.tail[1] = dir.d.tail[1];
 
@@ -1959,7 +1992,7 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     if (lfs->cfg->read_buffer) {
         lfs->rcache.buffer = lfs->cfg->read_buffer;
     } else {
-        lfs->rcache.buffer = malloc(lfs->cfg->read_size);
+        lfs->rcache.buffer = lfs_malloc(lfs->cfg->read_size);
         if (!lfs->rcache.buffer) {
             return LFS_ERR_NOMEM;
         }
@@ -1970,30 +2003,30 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     if (lfs->cfg->prog_buffer) {
         lfs->pcache.buffer = lfs->cfg->prog_buffer;
     } else {
-        lfs->pcache.buffer = malloc(lfs->cfg->prog_size);
+        lfs->pcache.buffer = lfs_malloc(lfs->cfg->prog_size);
         if (!lfs->pcache.buffer) {
             return LFS_ERR_NOMEM;
         }
     }
 
     // setup lookahead, round down to nearest 32-bits
-    assert(lfs->cfg->lookahead % 32 == 0);
-    assert(lfs->cfg->lookahead > 0);
+    LFS_ASSERT(lfs->cfg->lookahead % 32 == 0);
+    LFS_ASSERT(lfs->cfg->lookahead > 0);
     if (lfs->cfg->lookahead_buffer) {
         lfs->free.buffer = lfs->cfg->lookahead_buffer;
     } else {
-        lfs->free.buffer = malloc(lfs->cfg->lookahead/8);
+        lfs->free.buffer = lfs_malloc(lfs->cfg->lookahead/8);
         if (!lfs->free.buffer) {
             return LFS_ERR_NOMEM;
         }
     }
 
     // check that program and read sizes are multiples of the block size
-    assert(lfs->cfg->prog_size % lfs->cfg->read_size == 0);
-    assert(lfs->cfg->block_size % lfs->cfg->prog_size == 0);
+    LFS_ASSERT(lfs->cfg->prog_size % lfs->cfg->read_size == 0);
+    LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->prog_size == 0);
 
     // check that the block size is large enough to fit ctz pointers
-    assert(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
+    LFS_ASSERT(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
             <= lfs->cfg->block_size);
 
     // setup default state
@@ -2009,15 +2042,15 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
 static int lfs_deinit(lfs_t *lfs) {
     // free allocated memory
     if (!lfs->cfg->read_buffer) {
-        free(lfs->rcache.buffer);
+        lfs_free(lfs->rcache.buffer);
     }
 
     if (!lfs->cfg->prog_buffer) {
-        free(lfs->pcache.buffer);
+        lfs_free(lfs->pcache.buffer);
     }
 
     if (!lfs->cfg->lookahead_buffer) {
-        free(lfs->free.buffer);
+        lfs_free(lfs->free.buffer);
     }
 
     return 0;
@@ -2031,9 +2064,9 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
 
     // create free lookahead
     memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
-    lfs->free.begin = 0;
-    lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
     lfs->free.off = 0;
+    lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
+    lfs->free.i = 0;
     lfs_alloc_ack(lfs);
 
     // create superblock dir
@@ -2075,6 +2108,7 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
     superdir.d.size = sizeof(superdir.d) + sizeof(superblock.d) + 4;
 
     // write both pairs to be safe
+    lfs_superblock_tole32(&superblock.d);
     bool valid = false;
     for (int i = 0; i < 2; i++) {
         err = lfs_dir_commit(lfs, &superdir, (struct lfs_region[]){
@@ -2109,9 +2143,9 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
     }
 
     // setup free lookahead
-    lfs->free.begin = 0;
-    lfs->free.size = 0;
     lfs->free.off = 0;
+    lfs->free.size = 0;
+    lfs->free.i = 0;
     lfs_alloc_ack(lfs);
 
     // load superblock
@@ -2125,6 +2159,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
     if (!err) {
         err = lfs_bd_read(lfs, dir.pair[0], sizeof(dir.d),
                 &superblock.d, sizeof(superblock.d));
+        lfs_superblock_fromle32(&superblock.d);
         if (err) {
             return err;
         }
@@ -2134,7 +2169,7 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
     }
 
     if (err || memcmp(superblock.d.magic, "littlefs", 8) != 0) {
-        LFS_ERROR("Invalid superblock at %d %d", dir.pair[0], dir.pair[1]);
+        LFS_ERROR("Invalid superblock at %d %d", 0, 1);
         return LFS_ERR_CORRUPT;
     }
 
@@ -2182,6 +2217,7 @@ int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
         while (dir.off + sizeof(entry.d) <= (0x7fffffff & dir.d.size)-4) {
             err = lfs_bd_read(lfs, dir.pair[0], dir.off,
                     &entry.d, sizeof(entry.d));
+            lfs_entry_fromle32(&entry.d);
             if (err) {
                 return err;
             }
@@ -2222,7 +2258,7 @@ int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
             }
         }
     }
-    
+
     return 0;
 }
 
@@ -2256,7 +2292,7 @@ static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2],
     if (lfs_pairisnull(lfs->root)) {
         return 0;
     }
-    
+
     parent->d.tail[0] = 0;
     parent->d.tail[1] = 1;
 
@@ -2317,7 +2353,7 @@ static int lfs_moved(lfs_t *lfs, const void *e) {
                 break;
             }
 
-            if (!(0x80 & entry.d.type) && 
+            if (!(0x80 & entry.d.type) &&
                  memcmp(&entry.d.u, e, sizeof(entry.d.u)) == 0) {
                 return true;
             }

lfs.h

@@ -27,7 +27,7 @@
 // Software library version
 // Major (top-nibble), incremented on backwards incompatible changes
 // Minor (bottom-nibble), incremented on feature additions
-#define LFS_VERSION 0x00010002
+#define LFS_VERSION 0x00010003
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))
 
@@ -259,9 +259,9 @@ typedef struct lfs_superblock {
 } lfs_superblock_t;
 
 typedef struct lfs_free {
-    lfs_block_t begin;
-    lfs_block_t size;
     lfs_block_t off;
+    lfs_block_t size;
+    lfs_block_t i;
     lfs_block_t ack;
     uint32_t *buffer;
 } lfs_free_t;
@@ -320,10 +320,6 @@ int lfs_remove(lfs_t *lfs, const char *path);
 // If the destination exists, it must match the source in type.
 // If the destination is a directory, the directory must be empty.
 //
-// Note: If power loss occurs, it is possible that the file or directory
-// will exist in both the oldpath and newpath simultaneously after the
-// next mount.
-//
 // Returns a negative error code on failure.
 int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath);
 

lfs_util.c

@@ -17,7 +17,11 @@
  */
 #include "lfs_util.h"
 
+// Only compile if user does not provide custom config
+#ifndef LFS_CONFIG
 
+
+// Software CRC implementation with small lookup table
 void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
     static const uint32_t rtable[16] = {
         0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
@@ -34,3 +38,5 @@ void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
     }
 }
 
+
+#endif

lfs_util.h

@@ -18,13 +18,73 @@
 #ifndef LFS_UTIL_H
 #define LFS_UTIL_H
 
-#include <stdlib.h>
+// Users can override lfs_util.h with their own configuration by defining
+// LFS_CONFIG as a header file to include (-DLFS_CONFIG=lfs_config.h).
+//
+// If LFS_CONFIG is used, none of the default utils will be emitted and must be
+// provided by the config file. To start I would suggest copying lfs_util.h and
+// modifying as needed.
+#ifdef LFS_CONFIG
+#define LFS_STRINGIZE(x) LFS_STRINGIZE2(x)
+#define LFS_STRINGIZE2(x) #x
+#include LFS_STRINGIZE(LFS_CONFIG)
+#else
+
+// System includes
 #include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#ifndef LFS_NO_MALLOC
+#include <stdlib.h>
+#endif
+#ifndef LFS_NO_ASSERT
+#include <assert.h>
+#endif
+#if !defined(LFS_NO_DEBUG) || !defined(LFS_NO_WARN) || !defined(LFS_NO_ERROR)
 #include <stdio.h>
+#endif
 
 
-// Builtin functions, these may be replaced by more
-// efficient implementations in the system
+// Macros, may be replaced by system specific wrappers. Arguments to these
+// macros must not have side-effects as the macros can be removed for a smaller
+// code footprint
+
+// Logging functions
+#ifndef LFS_NO_DEBUG
+#define LFS_DEBUG(fmt, ...) \
+    printf("lfs debug:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS_DEBUG(fmt, ...)
+#endif
+
+#ifndef LFS_NO_WARN
+#define LFS_WARN(fmt, ...) \
+    printf("lfs warn:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS_WARN(fmt, ...)
+#endif
+
+#ifndef LFS_NO_ERROR
+#define LFS_ERROR(fmt, ...) \
+    printf("lfs error:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS_ERROR(fmt, ...)
+#endif
+
+// Runtime assertions
+#ifndef LFS_NO_ASSERT
+#define LFS_ASSERT(test) assert(test)
+#else
+#define LFS_ASSERT(test)
+#endif
+
+
+// Builtin functions, these may be replaced by more efficient
+// toolchain-specific implementations. LFS_NO_INTRINSICS falls back to a more
+// expensive basic C implementation for debugging purposes
+
+// Min/max functions for unsigned 32-bit numbers
 static inline uint32_t lfs_max(uint32_t a, uint32_t b) {
     return (a > b) ? a : b;
 }
@@ -33,31 +93,93 @@ static inline uint32_t lfs_min(uint32_t a, uint32_t b) {
     return (a < b) ? a : b;
 }
 
-static inline uint32_t lfs_ctz(uint32_t a) {
-    return __builtin_ctz(a);
-}
-
+// Find the next smallest power of 2 less than or equal to a
 static inline uint32_t lfs_npw2(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
     return 32 - __builtin_clz(a-1);
+#else
+    uint32_t r = 0;
+    uint32_t s;
+    a -= 1;
+    s = (a > 0xffff) << 4; a >>= s; r |= s;
+    s = (a > 0xff  ) << 3; a >>= s; r |= s;
+    s = (a > 0xf   ) << 2; a >>= s; r |= s;
+    s = (a > 0x3   ) << 1; a >>= s; r |= s;
+    return (r | (a >> 1)) + 1;
+#endif
 }
 
+// Count the number of trailing binary zeros in a
+// lfs_ctz(0) may be undefined
+static inline uint32_t lfs_ctz(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && defined(__GNUC__)
+    return __builtin_ctz(a);
+#else
+    return lfs_npw2((a & -a) + 1) - 1;
+#endif
+}
+
+// Count the number of binary ones in a
 static inline uint32_t lfs_popc(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
     return __builtin_popcount(a);
+#else
+    a = a - ((a >> 1) & 0x55555555);
+    a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
+    return (((a + (a >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
+#endif
 }
 
+// Find the sequence comparison of a and b, this is the distance
+// between a and b ignoring overflow
 static inline int lfs_scmp(uint32_t a, uint32_t b) {
     return (int)(unsigned)(a - b);
 }
 
-// CRC-32 with polynomial = 0x04c11db7
+// Convert from 32-bit little-endian to native order
+static inline uint32_t lfs_fromle32(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && ( \
+    (defined(  BYTE_ORDER  ) &&   BYTE_ORDER   ==   ORDER_LITTLE_ENDIAN  ) || \
+    (defined(__BYTE_ORDER  ) && __BYTE_ORDER   == __ORDER_LITTLE_ENDIAN  ) || \
+    (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
+    return a;
+#elif !defined(LFS_NO_INTRINSICS) && ( \
+    (defined(  BYTE_ORDER  ) &&   BYTE_ORDER   ==   ORDER_BIG_ENDIAN  ) || \
+    (defined(__BYTE_ORDER  ) && __BYTE_ORDER   == __ORDER_BIG_ENDIAN  ) || \
+    (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
+    return __builtin_bswap32(a);
+#else
+    return (((uint8_t*)&a)[0] <<  0) |
+           (((uint8_t*)&a)[1] <<  8) |
+           (((uint8_t*)&a)[2] << 16) |
+           (((uint8_t*)&a)[3] << 24);
+#endif
+}
+
+// Convert to 32-bit little-endian from native order
+static inline uint32_t lfs_tole32(uint32_t a) {
+    return lfs_fromle32(a);
+}
+
+// Calculate CRC-32 with polynomial = 0x04c11db7
 void lfs_crc(uint32_t *crc, const void *buffer, size_t size);
 
+// Allocate memory, only used if buffers are not provided to littlefs
+static inline void *lfs_malloc(size_t size) {
+#ifndef LFS_NO_MALLOC
+    return malloc(size);
+#else
+    return NULL;
+#endif
+}
 
-// Logging functions, these may be replaced by system-specific
-// logging functions
-#define LFS_DEBUG(fmt, ...) printf("lfs debug: " fmt "\n", __VA_ARGS__)
-#define LFS_WARN(fmt, ...)  printf("lfs warn: " fmt "\n", __VA_ARGS__)
-#define LFS_ERROR(fmt, ...) printf("lfs error: " fmt "\n", __VA_ARGS__)
+// Deallocate memory, only used if buffers are not provided to littlefs
+static inline void lfs_free(void *p) {
+#ifndef LFS_NO_MALLOC
+    free(p);
+#endif
+}
 
 
 #endif
+#endif

tests/test.py

@@ -33,10 +33,15 @@ def generate(test):
         pass
 
 def compile():
-    subprocess.check_call(['make', '--no-print-directory', '-s'])
+    subprocess.check_call([
+            os.environ.get('MAKE', 'make'),
+            '--no-print-directory', '-s'])
 
 def execute():
-    subprocess.check_call(["./lfs"])
+    if 'EXEC' in os.environ:
+        subprocess.check_call([os.environ['EXEC'], "./lfs"])
+    else:
+        subprocess.check_call(["./lfs"])
 
 def main(test=None):
     if test and not test.startswith('-'):

tests/test_alloc.sh

@@ -289,7 +289,7 @@ tests/test.py << TEST
     }
     lfs_file_close(&lfs, &file[0]) => 0;
 
-    // open whole
+    // open hole
     lfs_remove(&lfs, "bump") => 0;
 
     lfs_mkdir(&lfs, "splitdir") => 0;
@@ -301,5 +301,128 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
+echo "--- Outdated lookahead test ---"
+rm -rf blocks
+tests/test.py << TEST
+    lfs_format(&lfs, &cfg) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+
+    // fill completely with two files
+    lfs_file_open(&lfs, &file[0], "exhaustion1",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4)/2)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    lfs_file_open(&lfs, &file[0], "exhaustion2",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4+1)/2)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    // remount to force reset of lookahead
+    lfs_unmount(&lfs) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+
+    // rewrite one file
+    lfs_file_open(&lfs, &file[0], "exhaustion1",
+            LFS_O_WRONLY | LFS_O_TRUNC) => 0;
+    lfs_file_sync(&lfs, &file[0]) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4)/2)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    // rewrite second file, this requires lookahead does not
+    // use old population
+    lfs_file_open(&lfs, &file[0], "exhaustion2",
+            LFS_O_WRONLY | LFS_O_TRUNC) => 0;
+    lfs_file_sync(&lfs, &file[0]) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4+1)/2)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+TEST
+
+echo "--- Outdated lookahead and split dir test ---"
+rm -rf blocks
+tests/test.py << TEST
+    lfs_format(&lfs, &cfg) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+
+    // fill completely with two files
+    lfs_file_open(&lfs, &file[0], "exhaustion1",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4)/2)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    lfs_file_open(&lfs, &file[0], "exhaustion2",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4+1)/2)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    // remount to force reset of lookahead
+    lfs_unmount(&lfs) => 0;
+
+    lfs_mount(&lfs, &cfg) => 0;
+
+    // rewrite one file with a hole of one block
+    lfs_file_open(&lfs, &file[0], "exhaustion1",
+            LFS_O_WRONLY | LFS_O_TRUNC) => 0;
+    lfs_file_sync(&lfs, &file[0]) => 0;
+    size = strlen("blahblahblahblah");
+    memcpy(buffer, "blahblahblahblah", size);
+    for (lfs_size_t i = 0;
+            i < ((cfg.block_count-4)/2 - 1)*(cfg.block_size-8);
+            i += size) {
+        lfs_file_write(&lfs, &file[0], buffer, size) => size;
+    }
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    // try to allocate a directory, should fail!
+    lfs_mkdir(&lfs, "split") => LFS_ERR_NOSPC;
+
+    // file should not fail
+    lfs_file_open(&lfs, &file[0], "notasplit",
+            LFS_O_WRONLY | LFS_O_CREAT) => 0;
+    lfs_file_write(&lfs, &file[0], "hi", 2) => 2;
+    lfs_file_close(&lfs, &file[0]) => 0;
+
+    lfs_unmount(&lfs) => 0;
+TEST
+
 echo "--- Results ---"
 tests/stats.py

tests/test_dirs.sh

@@ -118,6 +118,7 @@ tests/test.py << TEST
         sprintf((char*)buffer, "test%d", i);
         lfs_dir_read(&lfs, &dir[0], &info) => 1;
         strcmp(info.name, (char*)buffer) => 0;
+        info.type => LFS_TYPE_DIR;
     }
     lfs_dir_read(&lfs, &dir[0], &info) => 0;
     lfs_unmount(&lfs) => 0;
@@ -355,5 +356,70 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
+echo "--- Multi-block directory with files ---"
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "prickly-pear") => 0;
+    for (int i = 0; i < $LARGESIZE; i++) {
+        sprintf((char*)buffer, "prickly-pear/test%d", i);
+        lfs_file_open(&lfs, &file[0], (char*)buffer,
+                LFS_O_WRONLY | LFS_O_CREAT) => 0;
+        size = 6;
+        memcpy(wbuffer, "Hello", size);
+        lfs_file_write(&lfs, &file[0], wbuffer, size) => size;
+        lfs_file_close(&lfs, &file[0]) => 0;
+    }
+    lfs_unmount(&lfs) => 0;
+TEST
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_dir_open(&lfs, &dir[0], "prickly-pear") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, ".") => 0;
+    info.type => LFS_TYPE_DIR;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "..") => 0;
+    info.type => LFS_TYPE_DIR;
+    for (int i = 0; i < $LARGESIZE; i++) {
+        sprintf((char*)buffer, "test%d", i);
+        lfs_dir_read(&lfs, &dir[0], &info) => 1;
+        strcmp(info.name, (char*)buffer) => 0;
+        info.type => LFS_TYPE_REG;
+        info.size => 6;
+    }
+    lfs_dir_read(&lfs, &dir[0], &info) => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+
+echo "--- Multi-block remove with files ---"
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_remove(&lfs, "prickly-pear") => LFS_ERR_NOTEMPTY;
+
+    for (int i = 0; i < $LARGESIZE; i++) {
+        sprintf((char*)buffer, "prickly-pear/test%d", i);
+        lfs_remove(&lfs, (char*)buffer) => 0;
+    }
+
+    lfs_remove(&lfs, "prickly-pear") => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_dir_open(&lfs, &dir[0], "/") => 0;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, ".") => 0;
+    info.type => LFS_TYPE_DIR;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "..") => 0;
+    info.type => LFS_TYPE_DIR;
+    lfs_dir_read(&lfs, &dir[0], &info) => 1;
+    strcmp(info.name, "burito") => 0;
+    info.type => LFS_TYPE_REG;
+    lfs_dir_read(&lfs, &dir[0], &info) => 0;
+    lfs_dir_close(&lfs, &dir[0]) => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+
 echo "--- Results ---"
 tests/stats.py

tests/test_files.sh

@@ -135,5 +135,24 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
+echo "--- Many file test ---"
+tests/test.py << TEST
+    lfs_format(&lfs, &cfg) => 0;
+TEST
+tests/test.py << TEST
+    // Create 300 files of 6 bytes
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_mkdir(&lfs, "directory") => 0;
+    for (unsigned i = 0; i < 300; i++) {
+        snprintf((char*)buffer, sizeof(buffer), "file_%03d", i);
+        lfs_file_open(&lfs, &file[0], (char*)buffer, LFS_O_WRONLY | LFS_O_CREAT) => 0;
+        size = 6;
+        memcpy(wbuffer, "Hello", size);
+        lfs_file_write(&lfs, &file[0], wbuffer, size) => size;
+        lfs_file_close(&lfs, &file[0]) => 0;
+    }
+    lfs_unmount(&lfs) => 0;
+TEST
+
 echo "--- Results ---"
 tests/stats.py

tests/test_interspersed.sh

@@ -1,13 +1,13 @@
 #!/bin/bash
 set -eu
 
-echo "=== Parallel tests ==="
+echo "=== Interspersed tests ==="
 rm -rf blocks
 tests/test.py << TEST
     lfs_format(&lfs, &cfg) => 0;
 TEST
 
-echo "--- Parallel file test ---"
+echo "--- Interspersed file test ---"
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
     lfs_file_open(&lfs, &file[0], "a", LFS_O_WRONLY | LFS_O_CREAT) => 0;
@@ -77,7 +77,7 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
-echo "--- Parallel remove file test ---"
+echo "--- Interspersed remove file test ---"
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
     lfs_file_open(&lfs, &file[0], "e", LFS_O_WRONLY | LFS_O_CREAT) => 0;

tests/test_paths.sh

@@ -90,6 +90,22 @@ tests/test.py << TEST
     lfs_unmount(&lfs) => 0;
 TEST
 
+echo "--- Trailing dot path tests ---"
+tests/test.py << TEST
+    lfs_mount(&lfs, &cfg) => 0;
+    lfs_stat(&lfs, "tea/hottea/", &info) => 0;
+    strcmp(info.name, "hottea") => 0;
+    lfs_stat(&lfs, "tea/hottea/.", &info) => 0;
+    strcmp(info.name, "hottea") => 0;
+    lfs_stat(&lfs, "tea/hottea/./.", &info) => 0;
+    strcmp(info.name, "hottea") => 0;
+    lfs_stat(&lfs, "tea/hottea/..", &info) => 0;
+    strcmp(info.name, "tea") => 0;
+    lfs_stat(&lfs, "tea/hottea/../.", &info) => 0;
+    strcmp(info.name, "tea") => 0;
+    lfs_unmount(&lfs) => 0;
+TEST
+
 echo "--- Root dot dot path tests ---"
 tests/test.py << TEST
     lfs_mount(&lfs, &cfg) => 0;
@@ -108,6 +124,10 @@ tests/test.py << TEST
     lfs_stat(&lfs, "/", &info) => 0;
     info.type => LFS_TYPE_DIR;
     strcmp(info.name, "/") => 0;
+
+    lfs_mkdir(&lfs, "/") => LFS_ERR_EXIST;
+    lfs_file_open(&lfs, &file[0], "/", LFS_O_WRONLY | LFS_O_CREAT)
+        => LFS_ERR_ISDIR;
     lfs_unmount(&lfs) => 0;
 TEST