Replaced emubd with rambd and filebd

The idea behind emubd (file per block), was neat, but doesn't add much
value over a block device that just operates on a single linear file
(other than adding a significant amount of overhead). Initially it
helped with debugging, but when the metadata format became more complex
in v2, most debugging ends up going through the debug.py script anyways.

Aside from being simpler, moving to filebd means it is also possible to
mount disk images directly.

Also introduced rambd, which keeps the disk contents in RAM. This is
very useful for testing where it increases the speed _significantly_.
- test_dirs w/ filebd - 0m7.170s
- test_dirs w/ rambd  - 0m0.966s

These follow the emubd model of using the lfs_config for geometry. I'm
not convinced this is the best approach, but it gets the job done.

I've also added lfs_ramdb_createcfg to add additional config similar to
lfs_file_opencfg. This is useful for specifying erase_value, which tells
the block device to simulate erases similar to flash devices. Note that
the default (-1) meets the minimum block device requirements and is the
most performant.

Makefile

@@ -7,7 +7,7 @@ CC ?= gcc
 AR ?= ar
 SIZE ?= size
 
-SRC += $(wildcard *.c emubd/*.c)
+SRC += $(wildcard *.c rambd/*.c filebd/*.c)
 OBJ := $(SRC:.c=.o)
 DEP := $(SRC:.c=.d)
 ASM := $(SRC:.c=.s)

emubd/lfs_emubd.c

@@ -1,414 +0,0 @@
-/*
- * Block device emulated on standard files
- *
- * Copyright (c) 2017, Arm Limited. All rights reserved.
- * SPDX-License-Identifier: BSD-3-Clause
- */
-#include "emubd/lfs_emubd.h"
-
-#include <errno.h>
-#include <string.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <limits.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <assert.h>
-#include <stdbool.h>
-#include <inttypes.h>
-
-
-// Emulated block device utils
-static inline void lfs_emubd_tole32(lfs_emubd_t *emu) {
-    emu->cfg.read_size     = lfs_tole32(emu->cfg.read_size);
-    emu->cfg.prog_size     = lfs_tole32(emu->cfg.prog_size);
-    emu->cfg.block_size    = lfs_tole32(emu->cfg.block_size);
-    emu->cfg.block_count   = lfs_tole32(emu->cfg.block_count);
-
-    emu->stats.read_count  = lfs_tole32(emu->stats.read_count);
-    emu->stats.prog_count  = lfs_tole32(emu->stats.prog_count);
-    emu->stats.erase_count = lfs_tole32(emu->stats.erase_count);
-
-    for (unsigned i = 0; i < sizeof(emu->history.blocks) /
-            sizeof(emu->history.blocks[0]); i++) {
-        emu->history.blocks[i] = lfs_tole32(emu->history.blocks[i]);
-    }
-}
-
-static inline void lfs_emubd_fromle32(lfs_emubd_t *emu) {
-    emu->cfg.read_size     = lfs_fromle32(emu->cfg.read_size);
-    emu->cfg.prog_size     = lfs_fromle32(emu->cfg.prog_size);
-    emu->cfg.block_size    = lfs_fromle32(emu->cfg.block_size);
-    emu->cfg.block_count   = lfs_fromle32(emu->cfg.block_count);
-
-    emu->stats.read_count  = lfs_fromle32(emu->stats.read_count);
-    emu->stats.prog_count  = lfs_fromle32(emu->stats.prog_count);
-    emu->stats.erase_count = lfs_fromle32(emu->stats.erase_count);
-
-    for (unsigned i = 0; i < sizeof(emu->history.blocks) /
-            sizeof(emu->history.blocks[0]); i++) {
-        emu->history.blocks[i] = lfs_fromle32(emu->history.blocks[i]);
-    }
-}
-
-
-// Block device emulated on existing filesystem
-int lfs_emubd_create(const struct lfs_config *cfg, const char *path) {
-    LFS_TRACE("lfs_emubd_create(%p {.context=%p, "
-                ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
-                ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
-                ".block_size=%"PRIu32", .block_count=%"PRIu32"}, \"%s\")",
-            (void*)cfg, cfg->context,
-            (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
-            (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
-            cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
-            path);
-    lfs_emubd_t *emu = cfg->context;
-    emu->cfg.read_size   = cfg->read_size;
-    emu->cfg.prog_size   = cfg->prog_size;
-    emu->cfg.block_size  = cfg->block_size;
-    emu->cfg.block_count = cfg->block_count;
-
-    // Allocate buffer for creating children files
-    size_t pathlen = strlen(path);
-    emu->path = malloc(pathlen + 1 + LFS_NAME_MAX + 1);
-    if (!emu->path) {
-        int err = -ENOMEM;
-        LFS_TRACE("lfs_emubd_create -> %"PRId32, err);
-        return err;
-    }
-
-    strcpy(emu->path, path);
-    emu->path[pathlen] = '/';
-    emu->child = &emu->path[pathlen+1];
-    memset(emu->child, '\0', LFS_NAME_MAX+1);
-
-    // Create directory if it doesn't exist
-    int err = mkdir(path, 0777);
-    if (err && errno != EEXIST) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_create -> %"PRId32, err);
-        return err;
-    }
-
-    // Load stats to continue incrementing
-    snprintf(emu->child, LFS_NAME_MAX, ".stats");
-    FILE *f = fopen(emu->path, "r");
-    if (!f) {
-        memset(&emu->stats, LFS_EMUBD_ERASE_VALUE, sizeof(emu->stats));
-    } else {
-        size_t res = fread(&emu->stats, sizeof(emu->stats), 1, f);
-        lfs_emubd_fromle32(emu);
-        if (res < 1) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_create -> %"PRId32, err);
-            fclose(f);
-            return err;
-        }
-
-        err = fclose(f);
-        if (err) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_create -> %"PRId32, err);
-            return err;
-        }
-    }
-
-    // Load history
-    snprintf(emu->child, LFS_NAME_MAX, ".history");
-    f = fopen(emu->path, "r");
-    if (!f) {
-        memset(&emu->history, 0, sizeof(emu->history));
-    } else {
-        size_t res = fread(&emu->history, sizeof(emu->history), 1, f);
-        lfs_emubd_fromle32(emu);
-        if (res < 1) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_create -> %"PRId32, err);
-            fclose(f);
-            return err;
-        }
-
-        err = fclose(f);
-        if (err) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_create -> %"PRId32, err);
-            return err;
-        }
-    }
-
-    LFS_TRACE("lfs_emubd_create -> %"PRId32, 0);
-    return 0;
-}
-
-void lfs_emubd_destroy(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_emubd_destroy(%p)", (void*)cfg);
-    lfs_emubd_sync(cfg);
-
-    lfs_emubd_t *emu = cfg->context;
-    free(emu->path);
-    LFS_TRACE("lfs_emubd_destroy -> %s", "void");
-}
-
-int lfs_emubd_read(const struct lfs_config *cfg, lfs_block_t block,
-        lfs_off_t off, void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_emubd_read(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
-            (void*)cfg, block, off, buffer, size);
-    lfs_emubd_t *emu = cfg->context;
-    uint8_t *data = buffer;
-
-    // Check if read is valid
-    LFS_ASSERT(off  % cfg->read_size == 0);
-    LFS_ASSERT(size % cfg->read_size == 0);
-    LFS_ASSERT(block < cfg->block_count);
-
-    // Zero out buffer for debugging
-    memset(data, 0, size);
-
-    // Read data
-    snprintf(emu->child, LFS_NAME_MAX, "%" PRIx32, block);
-
-    FILE *f = fopen(emu->path, "rb");
-    if (!f && errno != ENOENT) {
-        int err = -errno;
-        LFS_TRACE("lfs_emubd_read -> %d", err);
-        return err;
-    }
-
-    if (f) {
-        int err = fseek(f, off, SEEK_SET);
-        if (err) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_read -> %d", err);
-            fclose(f);
-            return err;
-        }
-
-        size_t res = fread(data, 1, size, f);
-        if (res < size && !feof(f)) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_read -> %d", err);
-            fclose(f);
-            return err;
-        }
-
-        err = fclose(f);
-        if (err) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_read -> %d", err);
-            return err;
-        }
-    }
-
-    emu->stats.read_count += size;
-    LFS_TRACE("lfs_emubd_read -> %d", 0);
-    return 0;
-}
-
-int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
-        lfs_off_t off, const void *buffer, lfs_size_t size) {
-    LFS_TRACE("lfs_emubd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
-            (void*)cfg, block, off, buffer, size);
-    lfs_emubd_t *emu = cfg->context;
-    const uint8_t *data = buffer;
-
-    // Check if write is valid
-    LFS_ASSERT(off  % cfg->prog_size == 0);
-    LFS_ASSERT(size % cfg->prog_size == 0);
-    LFS_ASSERT(block < cfg->block_count);
-
-    // Program data
-    snprintf(emu->child, LFS_NAME_MAX, "%" PRIx32, block);
-
-    FILE *f = fopen(emu->path, "r+b");
-    if (!f) {
-        int err = (errno == EACCES) ? 0 : -errno;
-        LFS_TRACE("lfs_emubd_prog -> %d", err);
-        return err;
-    }
-
-    // Check that file was erased
-    LFS_ASSERT(f);
-
-    int err = fseek(f, off, SEEK_SET);
-    if (err) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_prog -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    size_t res = fwrite(data, 1, size, f);
-    if (res < size) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_prog -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    err = fseek(f, off, SEEK_SET);
-    if (err) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_prog -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    uint8_t dat;
-    res = fread(&dat, 1, 1, f);
-    if (res < 1) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_prog -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    err = fclose(f);
-    if (err) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_prog -> %d", err);
-        return err;
-    }
-
-    // update history and stats
-    if (block != emu->history.blocks[0]) {
-        memmove(&emu->history.blocks[1], &emu->history.blocks[0],
-                sizeof(emu->history) - sizeof(emu->history.blocks[0]));
-        emu->history.blocks[0] = block;
-    }
-
-    emu->stats.prog_count += size;
-    LFS_TRACE("lfs_emubd_prog -> %d", 0);
-    return 0;
-}
-
-int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block) {
-    LFS_TRACE("lfs_emubd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
-    lfs_emubd_t *emu = cfg->context;
-
-    // Check if erase is valid
-    LFS_ASSERT(block < cfg->block_count);
-
-    // Erase the block
-    snprintf(emu->child, LFS_NAME_MAX, "%" PRIx32, block);
-    struct stat st;
-    int err = stat(emu->path, &st);
-    if (err && errno != ENOENT) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_erase -> %d", err);
-        return err;
-    }
-
-    if (!err && S_ISREG(st.st_mode) && (S_IWUSR & st.st_mode)) {
-        err = unlink(emu->path);
-        if (err) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_erase -> %d", err);
-            return err;
-        }
-    }
-
-    if (err || (S_ISREG(st.st_mode) && (S_IWUSR & st.st_mode))) {
-        FILE *f = fopen(emu->path, "w");
-        if (!f) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_erase -> %d", err);
-            return err;
-        }
-
-        err = fclose(f);
-        if (err) {
-            err = -errno;
-            LFS_TRACE("lfs_emubd_erase -> %d", err);
-            return err;
-        }
-    }
-
-    emu->stats.erase_count += cfg->block_size;
-    LFS_TRACE("lfs_emubd_erase -> %d", 0);
-    return 0;
-}
-
-int lfs_emubd_sync(const struct lfs_config *cfg) {
-    LFS_TRACE("lfs_emubd_sync(%p)", (void*)cfg);
-    lfs_emubd_t *emu = cfg->context;
-
-    // Just write out info/stats for later lookup
-    snprintf(emu->child, LFS_NAME_MAX, ".config");
-    FILE *f = fopen(emu->path, "w");
-    if (!f) {
-        int err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        return err;
-    }
-
-    lfs_emubd_tole32(emu);
-    size_t res = fwrite(&emu->cfg, sizeof(emu->cfg), 1, f);
-    lfs_emubd_fromle32(emu);
-    if (res < 1) {
-        int err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    int err = fclose(f);
-    if (err) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        return err;
-    }
-
-    snprintf(emu->child, LFS_NAME_MAX, ".stats");
-    f = fopen(emu->path, "w");
-    if (!f) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        return err;
-    }
-
-    lfs_emubd_tole32(emu);
-    res = fwrite(&emu->stats, sizeof(emu->stats), 1, f);
-    lfs_emubd_fromle32(emu);
-    if (res < 1) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    err = fclose(f);
-    if (err) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        return err;
-    }
-
-    snprintf(emu->child, LFS_NAME_MAX, ".history");
-    f = fopen(emu->path, "w");
-    if (!f) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        return err;
-    }
-
-    lfs_emubd_tole32(emu);
-    res = fwrite(&emu->history, sizeof(emu->history), 1, f);
-    lfs_emubd_fromle32(emu);
-    if (res < 1) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        fclose(f);
-        return err;
-    }
-
-    err = fclose(f);
-    if (err) {
-        err = -errno;
-        LFS_TRACE("lfs_emubd_sync -> %d", err);
-        return err;
-    }
-
-    LFS_TRACE("lfs_emubd_sync -> %d", 0);
-    return 0;
-}

emubd/lfs_emubd.h

@@ -1,79 +0,0 @@
-/*
- * Block device emulated on standard files
- *
- * Copyright (c) 2017, Arm Limited. All rights reserved.
- * SPDX-License-Identifier: BSD-3-Clause
- */
-#ifndef LFS_EMUBD_H
-#define LFS_EMUBD_H
-
-#include "lfs.h"
-#include "lfs_util.h"
-
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
-
-// Config options
-#ifndef LFS_EMUBD_ERASE_VALUE
-#define LFS_EMUBD_ERASE_VALUE 0x00
-#endif
-
-
-// The emu bd state
-typedef struct lfs_emubd {
-    char *path;
-    char *child;
-
-    struct {
-        uint64_t read_count;
-        uint64_t prog_count;
-        uint64_t erase_count;
-    } stats;
-
-    struct {
-        lfs_block_t blocks[4];
-    } history;
-
-    struct {
-        uint32_t read_size;
-        uint32_t prog_size;
-        uint32_t block_size;
-        uint32_t block_count;
-    } cfg;
-} lfs_emubd_t;
-
-
-// Create a block device using path for the directory to store blocks
-int lfs_emubd_create(const struct lfs_config *cfg, const char *path);
-
-// Clean up memory associated with emu block device
-void lfs_emubd_destroy(const struct lfs_config *cfg);
-
-// Read a block
-int lfs_emubd_read(const struct lfs_config *cfg, lfs_block_t block,
-        lfs_off_t off, void *buffer, lfs_size_t size);
-
-// Program a block
-//
-// The block must have previously been erased.
-int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
-        lfs_off_t off, const void *buffer, lfs_size_t size);
-
-// Erase a block
-//
-// A block must be erased before being programmed. The
-// state of an erased block is undefined.
-int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block);
-
-// Sync the block device
-int lfs_emubd_sync(const struct lfs_config *cfg);
-
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-#endif

filebd/lfs_filebd.c

@@ -0,0 +1,198 @@
+/*
+ * Block device emulated in a file
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "filebd/lfs_filebd.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+int lfs_filebd_createcfg(const struct lfs_config *cfg, const char *path,
+        const struct lfs_filebd_config *filecfg) {
+    LFS_TRACE("lfs_filebd_createcfg(%p {.context=%p, "
+                ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
+                ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
+                ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
+                "\"%s\", "
+                "%p {.erase_value=%"PRId32"})",
+            (void*)cfg, cfg->context,
+            (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
+            (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
+            cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
+            path, (void*)filecfg, filecfg->erase_value);
+    lfs_filebd_t *bd = cfg->context;
+    bd->cfg = filecfg;
+
+    // open file
+    bd->fd = open(path, O_RDWR | O_CREAT, 0666);
+    if (bd->fd < 0) {
+        int err = -errno;
+        LFS_TRACE("lfs_filebd_createcfg -> %d", err);
+        return err;
+    }
+
+    LFS_TRACE("lfs_filebd_createcfg -> %d", 0);
+    return 0;
+}
+
+int lfs_filebd_create(const struct lfs_config *cfg, const char *path) {
+    LFS_TRACE("lfs_filebd_create(%p {.context=%p, "
+                ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
+                ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
+                ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
+                "\"%s\")",
+            (void*)cfg, cfg->context,
+            (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
+            (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
+            cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
+            path);
+    static const struct lfs_filebd_config defaults = {.erase_value=-1};
+    int err = lfs_filebd_createcfg(cfg, path, &defaults);
+    LFS_TRACE("lfs_filebd_create -> %d", err);
+    return err;
+}
+
+void lfs_filebd_destroy(const struct lfs_config *cfg) {
+    LFS_TRACE("lfs_filebd_destroy(%p)", (void*)cfg);
+    lfs_filebd_t *bd = cfg->context;
+    close(bd->fd);
+    LFS_TRACE("lfs_filebd_destroy -> %s", "void");
+}
+
+int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, void *buffer, lfs_size_t size) {
+    LFS_TRACE("lfs_filebd_read(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+            (void*)cfg, block, off, buffer, size);
+    lfs_filebd_t *bd = cfg->context;
+
+    // check if read is valid
+    LFS_ASSERT(off  % cfg->read_size == 0);
+    LFS_ASSERT(size % cfg->read_size == 0);
+    LFS_ASSERT(block < cfg->block_count);
+
+    // zero for reproducability (in case file is truncated)
+    if (bd->cfg->erase_value != -1) {
+        memset(buffer, bd->cfg->erase_value, size);
+    }
+
+    // read
+    off_t res1 = lseek(bd->fd,
+            (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
+    if (res1 < 0) {
+        int err = -errno;
+        LFS_TRACE("lfs_filebd_read -> %d", err);
+        return err;
+    }
+
+    ssize_t res2 = read(bd->fd, buffer, size);
+    if (res2 < 0) {
+        int err = -errno;
+        LFS_TRACE("lfs_filebd_read -> %d", err);
+        return err;
+    }
+
+    LFS_TRACE("lfs_filebd_read -> %d", 0);
+    return 0;
+}
+
+int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, const void *buffer, lfs_size_t size) {
+    LFS_TRACE("lfs_filebd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+            (void*)cfg, block, off, buffer, size);
+    lfs_filebd_t *bd = cfg->context;
+
+    // check if write is valid
+    LFS_ASSERT(off  % cfg->prog_size == 0);
+    LFS_ASSERT(size % cfg->prog_size == 0);
+    LFS_ASSERT(block < cfg->block_count);
+
+    // check that data was erased? only needed for testing
+    if (bd->cfg->erase_value != -1) {
+        off_t res1 = lseek(bd->fd,
+                (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
+        if (res1 < 0) {
+            int err = -errno;
+            LFS_TRACE("lfs_filebd_prog -> %d", err);
+            return err;
+        }
+
+        for (lfs_off_t i = 0; i < size; i++) {
+            uint8_t c;
+            ssize_t res2 = read(bd->fd, &c, 1);
+            if (res2 < 0) {
+                int err = -errno;
+                LFS_TRACE("lfs_filebd_prog -> %d", err);
+                return err;
+            }
+
+            LFS_ASSERT(c == bd->cfg->erase_value);
+        }
+    }
+
+    // program data
+    off_t res1 = lseek(bd->fd,
+            (off_t)block*cfg->block_size + (off_t)off, SEEK_SET);
+    if (res1 < 0) {
+        int err = -errno;
+        LFS_TRACE("lfs_filebd_prog -> %d", err);
+        return err;
+    }
+
+    ssize_t res2 = write(bd->fd, buffer, size);
+    if (res2 < 0) {
+        int err = -errno;
+        LFS_TRACE("lfs_filebd_prog -> %d", err);
+        return err;
+    }
+
+    LFS_TRACE("lfs_filebd_prog -> %d", 0);
+    return 0;
+}
+
+int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
+    LFS_TRACE("lfs_filebd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
+    lfs_filebd_t *bd = cfg->context;
+
+    // check if erase is valid
+    LFS_ASSERT(block < cfg->block_count);
+
+    // erase, only needed for testing
+    if (bd->cfg->erase_value != -1) {
+        off_t res1 = lseek(bd->fd, (off_t)block*cfg->block_size, SEEK_SET);
+        if (res1 < 0) {
+            int err = -errno;
+            LFS_TRACE("lfs_filebd_erase -> %d", err);
+            return err;
+        }
+
+        for (lfs_off_t i = 0; i < cfg->block_size; i++) {
+            ssize_t res2 = write(bd->fd, &(uint8_t){bd->cfg->erase_value}, 1);
+            if (res2 < 0) {
+                int err = -errno;
+                LFS_TRACE("lfs_filebd_erase -> %d", err);
+                return err;
+            }
+        }
+    }
+
+    LFS_TRACE("lfs_filebd_erase -> %d", 0);
+    return 0;
+}
+
+int lfs_filebd_sync(const struct lfs_config *cfg) {
+    LFS_TRACE("lfs_filebd_sync(%p)", (void*)cfg);
+    // file sync
+    lfs_filebd_t *bd = cfg->context;
+    int err = fsync(bd->fd);
+    if (err) {
+        err = -errno;
+        LFS_TRACE("lfs_filebd_sync -> %d", 0);
+        return err;
+    }
+
+    LFS_TRACE("lfs_filebd_sync -> %d", 0);
+    return 0;
+}

filebd/lfs_filebd.h

@@ -0,0 +1,64 @@
+/*
+ * Block device emulated in a file
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS_FILEBD_H
+#define LFS_FILEBD_H
+
+#include "lfs.h"
+#include "lfs_util.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+// filebd config (optional)
+struct lfs_filebd_config {
+    // 8-bit erase value to simulate erasing with. -1 indicates no erase
+    // occurs, which is still a valid block device
+    int32_t erase_value;
+};
+
+// filebd state
+typedef struct lfs_filebd {
+    int fd;
+    const struct lfs_filebd_config *cfg;
+} lfs_filebd_t;
+
+
+// Create a file block device using the geometry in lfs_config
+int lfs_filebd_create(const struct lfs_config *cfg, const char *path);
+int lfs_filebd_createcfg(const struct lfs_config *cfg, const char *path,
+        const struct lfs_filebd_config *ramcfg);
+
+// Clean up memory associated with block device
+void lfs_filebd_destroy(const struct lfs_config *cfg);
+
+// Read a block
+int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, void *buffer, lfs_size_t size);
+
+// Program a block
+//
+// The block must have previously been erased.
+int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, const void *buffer, lfs_size_t size);
+
+// Erase a block
+//
+// A block must be erased before being programmed. The
+// state of an erased block is undefined.
+int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block);
+
+// Sync the block device
+int lfs_filebd_sync(const struct lfs_config *cfg);
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif

rambd/lfs_rambd.c

@@ -0,0 +1,137 @@
+/*
+ * Block device emulated in RAM
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "rambd/lfs_rambd.h"
+
+int lfs_rambd_createcfg(const struct lfs_config *cfg,
+        const struct lfs_rambd_config *ramcfg) {
+    LFS_TRACE("lfs_rambd_createcfg(%p {.context=%p, "
+                ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
+                ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
+                ".block_size=%"PRIu32", .block_count=%"PRIu32"}, "
+                "%p {.erase_value=%"PRId32", .buffer=%p})",
+            (void*)cfg, cfg->context,
+            (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
+            (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
+            cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count,
+            (void*)ramcfg, ramcfg->erase_value, ramcfg->buffer);
+    lfs_rambd_t *bd = cfg->context;
+    bd->cfg = ramcfg;
+
+    // allocate buffer?
+    if (bd->cfg->buffer) {
+        bd->buffer = bd->cfg->buffer;
+    } else {
+        bd->buffer = lfs_malloc(cfg->block_size * cfg->block_count);
+        if (!bd->buffer) {
+            LFS_TRACE("lfs_rambd_createcfg -> %d", LFS_ERR_NOMEM);
+            return LFS_ERR_NOMEM;
+        }
+    }
+
+    // zero for reproducability?
+    if (bd->cfg->erase_value != -1) {
+        memset(bd->buffer, bd->cfg->erase_value,
+                cfg->block_size * cfg->block_count);
+    }
+
+    LFS_TRACE("lfs_rambd_createcfg -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_create(const struct lfs_config *cfg) {
+    LFS_TRACE("lfs_rambd_create(%p {.context=%p, "
+                ".read=%p, .prog=%p, .erase=%p, .sync=%p, "
+                ".read_size=%"PRIu32", .prog_size=%"PRIu32", "
+                ".block_size=%"PRIu32", .block_count=%"PRIu32"})",
+            (void*)cfg, cfg->context,
+            (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
+            (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
+            cfg->read_size, cfg->prog_size, cfg->block_size, cfg->block_count);
+    static const struct lfs_rambd_config defaults = {.erase_value=-1};
+    int err = lfs_rambd_createcfg(cfg, &defaults);
+    LFS_TRACE("lfs_rambd_create -> %d", err);
+    return err;
+}
+
+void lfs_rambd_destroy(const struct lfs_config *cfg) {
+    LFS_TRACE("lfs_rambd_destroy(%p)", (void*)cfg);
+    // clean up memory
+    lfs_rambd_t *bd = cfg->context;
+    if (!bd->cfg->buffer) {
+        lfs_free(bd->buffer);
+    }
+    LFS_TRACE("lfs_rambd_destroy -> %s", "void");
+}
+
+int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, void *buffer, lfs_size_t size) {
+    LFS_TRACE("lfs_rambd_read(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+            (void*)cfg, block, off, buffer, size);
+    lfs_rambd_t *bd = cfg->context;
+
+    // check if read is valid
+    LFS_ASSERT(off  % cfg->read_size == 0);
+    LFS_ASSERT(size % cfg->read_size == 0);
+    LFS_ASSERT(block < cfg->block_count);
+
+    // read data
+    memcpy(buffer, &bd->buffer[block*cfg->block_size + off], size);
+
+    LFS_TRACE("lfs_rambd_read -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, const void *buffer, lfs_size_t size) {
+    LFS_TRACE("lfs_rambd_prog(%p, 0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+            (void*)cfg, block, off, buffer, size);
+    lfs_rambd_t *bd = cfg->context;
+
+    // check if write is valid
+    LFS_ASSERT(off  % cfg->prog_size == 0);
+    LFS_ASSERT(size % cfg->prog_size == 0);
+    LFS_ASSERT(block < cfg->block_count);
+
+    // check that data was erased? only needed for testing
+    if (bd->cfg->erase_value != -1) {
+        for (lfs_off_t i = 0; i < size; i++) {
+            LFS_ASSERT(bd->buffer[block*cfg->block_size + off + i] ==
+                    bd->cfg->erase_value);
+        }
+    }
+
+    // program data
+    memcpy(&bd->buffer[block*cfg->block_size + off], buffer, size);
+
+    LFS_TRACE("lfs_rambd_prog -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block) {
+    LFS_TRACE("lfs_rambd_erase(%p, 0x%"PRIx32")", (void*)cfg, block);
+    lfs_rambd_t *bd = cfg->context;
+
+    // check if erase is valid
+    LFS_ASSERT(block < cfg->block_count);
+
+    // erase, only needed for testing
+    if (bd->cfg->erase_value != -1) {
+        memset(&bd->buffer[block*cfg->block_size],
+                bd->cfg->erase_value, cfg->block_size);
+    }
+
+    LFS_TRACE("lfs_rambd_erase -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_sync(const struct lfs_config *cfg) {
+    LFS_TRACE("lfs_rambd_sync(%p)", (void*)cfg);
+    // sync does nothing because we aren't backed by anything real
+    (void)cfg;
+    LFS_TRACE("lfs_rambd_sync -> %d", 0);
+    return 0;
+}

rambd/lfs_rambd.h

@@ -0,0 +1,67 @@
+/*
+ * Block device emulated in RAM
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS_RAMBD_H
+#define LFS_RAMBD_H
+
+#include "lfs.h"
+#include "lfs_util.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+// rambd config (optional)
+struct lfs_rambd_config {
+    // 8-bit erase value to simulate erasing with. -1 indicates no erase
+    // occurs, which is still a valid block device
+    int32_t erase_value;
+
+    // Optional statically allocated buffer for the block device.
+    void *buffer;
+};
+
+// rambd state
+typedef struct lfs_rambd {
+    uint8_t *buffer;
+    const struct lfs_rambd_config *cfg;
+} lfs_rambd_t;
+
+
+// Create a RAM block device using the geometry in lfs_config
+int lfs_rambd_create(const struct lfs_config *cfg);
+int lfs_rambd_createcfg(const struct lfs_config *cfg,
+        const struct lfs_rambd_config *ramcfg);
+
+// Clean up memory associated with block device
+void lfs_rambd_destroy(const struct lfs_config *cfg);
+
+// Read a block
+int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, void *buffer, lfs_size_t size);
+
+// Program a block
+//
+// The block must have previously been erased.
+int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, const void *buffer, lfs_size_t size);
+
+// Erase a block
+//
+// A block must be erased before being programmed. The
+// state of an erased block is undefined.
+int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block);
+
+// Sync the block device
+int lfs_rambd_sync(const struct lfs_config *cfg);
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif

scripts/test_.py

@@ -15,7 +15,6 @@ import subprocess as sp
 import base64
 import sys
 import copy
-import shutil
 import shlex
 
 TESTDIR = 'tests_'
@@ -40,8 +39,10 @@ $(foreach target,$(SRC),$(eval $(FLATTEN)))
 GLOBALS = """
 //////////////// AUTOGENERATED TEST ////////////////
 #include "lfs.h"
-#include "emubd/lfs_emubd.h"
+#include "filebd/lfs_filebd.h"
+#include "rambd/lfs_rambd.h"
 #include <stdio.h>
+const char *LFS_DISK = NULL;
 """
 DEFINES = {
     "LFS_READ_SIZE": 16,
@@ -51,23 +52,25 @@ DEFINES = {
     "LFS_BLOCK_CYCLES": 1024,
     "LFS_CACHE_SIZE": "(64 % LFS_PROG_SIZE == 0 ? 64 : LFS_PROG_SIZE)",
     "LFS_LOOKAHEAD_SIZE": 16,
+    "LFS_ERASE_VALUE": 0xff,
 }
 PROLOGUE = """
     // prologue
     __attribute__((unused)) lfs_t lfs;
-    __attribute__((unused)) lfs_emubd_t bd;
+    __attribute__((unused)) lfs_filebd_t filebd;
+    __attribute__((unused)) lfs_rambd_t rambd;
     __attribute__((unused)) lfs_file_t file;
     __attribute__((unused)) lfs_dir_t dir;
     __attribute__((unused)) struct lfs_info info;
     __attribute__((unused)) uint8_t buffer[1024];
     __attribute__((unused)) char path[1024];
-
+    
     __attribute__((unused)) const struct lfs_config cfg = {
-        .context = &bd,
-        .read  = &lfs_emubd_read,
-        .prog  = &lfs_emubd_prog,
-        .erase = &lfs_emubd_erase,
-        .sync  = &lfs_emubd_sync,
+        .context = LFS_DISK ? (void*)&filebd : (void*)&rambd,
+        .read  = LFS_DISK ? &lfs_filebd_read  : &lfs_rambd_read,
+        .prog  = LFS_DISK ? &lfs_filebd_prog  : &lfs_rambd_prog,
+        .erase = LFS_DISK ? &lfs_filebd_erase : &lfs_rambd_erase,
+        .sync  = LFS_DISK ? &lfs_filebd_sync  : &lfs_rambd_sync,
 
         .read_size      = LFS_READ_SIZE,
         .prog_size      = LFS_PROG_SIZE,
@@ -78,11 +81,26 @@ PROLOGUE = """
         .lookahead_size = LFS_LOOKAHEAD_SIZE,
     };
 
-    lfs_emubd_create(&cfg, "blocks");
+    __attribute__((unused)) const struct lfs_filebd_config filecfg = {
+        .erase_value = LFS_ERASE_VALUE,
+    };
+    __attribute__((unused)) const struct lfs_rambd_config ramcfg = {
+        .erase_value = LFS_ERASE_VALUE,
+    };
+
+    if (LFS_DISK) {
+        lfs_filebd_createcfg(&cfg, LFS_DISK, &filecfg);
+    } else {
+        lfs_rambd_createcfg(&cfg, &ramcfg);
+    }
 """
 EPILOGUE = """
     // epilogue
-    lfs_emubd_destroy(&cfg);
+    if (LFS_DISK) {
+        lfs_filebd_destroy(&cfg);
+    } else {
+        lfs_rambd_destroy(&cfg);
+    }
 """
 PASS = '\033[32m✓\033[0m'
 FAIL = '\033[31m✗\033[0m'
@@ -133,7 +151,8 @@ class TestCase:
         f.write(') {\n')
 
         for k, v in sorted(self.defines.items()):
-            f.write(4*' '+'#define %s %s\n' % (k, v))
+            if k not in self.suite.defines:
+                f.write(4*' '+'#define %s %s\n' % (k, v))
 
         f.write(PROLOGUE)
         f.write('\n')
@@ -148,27 +167,34 @@ class TestCase:
         f.write('\n')
 
         for k, v in sorted(self.defines.items()):
-            f.write(4*' '+'#undef %s\n' % k)
+            if k not in self.suite.defines:
+                f.write(4*' '+'#undef %s\n' % k)
 
         f.write('}\n')
 
     def test(self, exec=[], persist=False, gdb=False, failure=None, **args):
-        # clear disk first
-        if not persist:
-            shutil.rmtree('blocks', True)
-
         # build command
         cmd = exec + ['./%s.test' % self.suite.path,
             repr(self.caseno), repr(self.permno)]
+        if persist:
+            cmd.append(self.suite.path + '.test.disk')
 
         # failed? drop into debugger?
         if gdb and failure:
-            cmd = (['gdb', '-ex', 'r'
-                ] + (['-ex', 'up'] if failure.assert_ else []) + [
-                '--args'] + cmd)
+            ncmd = ['gdb']
+            if gdb == 'assert':
+                ncmd.extend(['-ex', 'r'])
+                if failure.assert_:
+                    ncmd.extend(['-ex', 'up'])
+            elif gdb == 'start':
+                ncmd.extend([
+                    '-ex', 'b %s:%d' % (self.suite.path, self.lineno),
+                    '-ex', 'r'])
+            ncmd.extend(['--args'] + cmd)
+
             if args.get('verbose', False):
-                print(' '.join(shlex.quote(c) for c in cmd))
-            sys.exit(sp.call(cmd))
+                print(' '.join(shlex.quote(c) for c in ncmd))
+            sys.exit(sp.call(ncmd))
 
         # run test case!
         stdout = []
@@ -231,22 +257,27 @@ class ReentrantTestCase(TestCase):
         if not self.reentrant:
             return
 
-        for cycles in it.count(1):
-            npersist = persist or cycles > 1
+        # clear disk first?
+        if not persist:
+            try:
+                os.remove(self.suite.path + '.test.disk')
+            except FileNotFoundError:
+                pass
 
+        for cycles in it.count(1):
             # exact cycle we should drop into debugger?
             if gdb and failure and failure.cycleno == cycles:
-                return super().test(exec=exec, persist=npersist,
+                return super().test(exec=exec, persist=True,
                     gdb=gdb, failure=failure, **args)
 
-            # run tests, but kill the program after lfs_emubd_prog/erase has
+            # run tests, but kill the program after prog/erase has
             # been hit n cycles. We exit with a special return code if the
             # program has not finished, since this isn't a test failure.
             nexec = exec + [
                 'gdb', '-batch-silent',
                 '-ex', 'handle all nostop',
-                '-ex', 'b lfs_emubd_prog',
-                '-ex', 'b lfs_emubd_erase',
+                '-ex', 'b lfs_filebd_prog',
+                '-ex', 'b lfs_filebd_erase',
                 '-ex', 'r',
                 ] + cycles*['-ex', 'c'] + [
                 '-ex', 'q '
@@ -255,7 +286,7 @@ class ReentrantTestCase(TestCase):
                     '33',
                 '--args']
             try:
-                return super().test(exec=nexec, persist=npersist, **args)
+                return super().test(exec=nexec, persist=True, **args)
             except TestFailure as nfailure:
                 if nfailure.returncode == 33:
                     continue
@@ -370,10 +401,11 @@ class TestSuite:
 
         f.write('\n')
         f.write('int main(int argc, char **argv) {\n')
-        f.write(4*' '+'int case_ = (argc == 3) ? atoi(argv[1]) : 0;\n')
-        f.write(4*' '+'int perm = (argc == 3) ? atoi(argv[2]) : 0;\n')
+        f.write(4*' '+'int case_ = (argc >= 3) ? atoi(argv[1]) : 0;\n')
+        f.write(4*' '+'int perm = (argc >= 3) ? atoi(argv[2]) : 0;\n')
+        f.write(4*' '+'LFS_DISK = (argc >= 4) ? argv[3] : NULL;\n')
         for perm in self.perms:
-            f.write(4*' '+'if (argc != 3 || '
+            f.write(4*' '+'if (argc < 3 || '
                 '(case_ == %d && perm == %d)) { ' % (
                     perm.caseno, perm.permno))
             f.write('test_case%d(' % perm.caseno)
@@ -590,8 +622,9 @@ if __name__ == "__main__":
         help="Run all tests instead of stopping on first error. Useful for CI.")
     parser.add_argument('-p', '--persist', action='store_true',
         help="Don't reset the tests disk before each test.")
-    parser.add_argument('-g', '--gdb', action='store_true',
-        help="Drop into gdb on failure.")
+    parser.add_argument('-g', '--gdb', choices=['init', 'start', 'assert'],
+        nargs='?', const='assert',
+        help="Drop into gdb on test failure.")
     parser.add_argument('--valgrind', action='store_true',
         help="Run non-leaky tests under valgrind to check for memory leaks.")
     parser.add_argument('--reentrant', action='store_true',