mkimxboot: refactor code, no functional change

The mkimxboot was becoming messy with juge functions and
redundant code. Factor reading/writing/loading code into smaller
functions. Introduce the concept of rockbox firmware to simplify
support of other formats than scramble.

Change-Id: I3a61295ca5abca1a0eee8c9e8709c6b8dfa256a6

2 files changed, 252 insertions, 222 deletions

diff --git a/rbutil/mkimxboot/mkimxboot.c b/rbutil/mkimxboot/mkimxboot.c
index d420afce5d..da1e49876d 100644
--- a/rbutil/mkimxboot/mkimxboot.c
+++ b/rbutil/mkimxboot/mkimxboot.c
@@ -28,6 +28,14 @@
 #include "dualboot.h"
 #include "md5.h"
 
+/* abstract structure to represent a Rockbox firmware. It can be a scrambled file
+ * or an ELF file or whatever. */
+struct rb_fw_t
+{
+    void *boot;
+    size_t boot_sz;
+};
+
 struct imx_fw_variant_desc_t
 {
     /* Offset within file */
@@ -160,7 +168,7 @@ static const struct imx_model_desc_t imx_models[] =
 #define MAGIC_NORMAL    0xcafebabe
 
 static enum imx_error_t patch_std_zero_host_play(int jump_before, int model,
- enum imx_output_type_t type, struct sb_file_t *sb_file, void *boot, size_t boot_sz)
+    enum imx_output_type_t type, struct sb_file_t *sb_file, struct rb_fw_t boot_fw)
 {
     /* We assume the file has three boot sections: ____, host, play and one
      * resource section rsrc.
@@ -229,8 +237,8 @@ static enum imx_error_t patch_std_zero_host_play(int jump_before, int model,
         rock_sec.insts = xmalloc(2 * sizeof(struct sb_inst_t));
         memset(rock_sec.insts, 0, 2 * sizeof(struct sb_inst_t));
         rock_sec.insts[0].inst = SB_INST_LOAD;
-        rock_sec.insts[0].size = boot_sz;
-        rock_sec.insts[0].data = memdup(boot, boot_sz);
+        rock_sec.insts[0].size = boot_fw.boot_sz;
+        rock_sec.insts[0].data = memdup(boot_fw.boot, boot_fw.boot_sz);
         rock_sec.insts[0].addr = imx_models[model].bootloader_addr;
         rock_sec.insts[1].inst = SB_INST_JUMP;
         rock_sec.insts[1].addr = imx_models[model].bootloader_addr;
@@ -253,13 +261,13 @@ static enum imx_error_t patch_std_zero_host_play(int jump_before, int model,
             sb_free_instruction(sec->insts[i]);
         memset(new_insts + jump_idx, 0, 2 * sizeof(struct sb_inst_t));
         new_insts[jump_idx + 0].inst = SB_INST_LOAD;
-        new_insts[jump_idx + 0].size = boot_sz;
-        new_insts[jump_idx + 0].data = memdup(boot, boot_sz);
+        new_insts[jump_idx + 0].size = boot_fw.boot_sz;
+        new_insts[jump_idx + 0].data = memdup(boot_fw.boot, boot_fw.boot_sz);
         new_insts[jump_idx + 0].addr = imx_models[model].bootloader_addr;
         new_insts[jump_idx + 1].inst = SB_INST_JUMP;
         new_insts[jump_idx + 1].addr = imx_models[model].bootloader_addr;
         new_insts[jump_idx + 1].argument = recovery ? MAGIC_RECOVERY : MAGIC_NORMAL;
-        
+
         free(sec->insts);
         sec->insts = new_insts;
         sec->nr_insts = jump_idx + 2;
@@ -327,7 +335,7 @@ static enum imx_error_t parse_version(const char *s, struct sb_version_t *ver)
 
 static enum imx_error_t patch_firmware(enum imx_model_t model,
     enum imx_firmware_variant_t variant, enum imx_output_type_t type,
-    struct sb_file_t *sb_file, void *boot, size_t boot_sz,
+    struct sb_file_t *sb_file, struct rb_fw_t boot_fw,
     const char *force_version)
 {
     if(force_version)
@@ -342,11 +350,11 @@ static enum imx_error_t patch_firmware(enum imx_model_t model,
         case MODEL_FUZEPLUS:
             /* The Fuze+ uses the standard ____, host, play sections, patch after third
              * call in ____ section */
-            return patch_std_zero_host_play(3, model, type, sb_file, boot, boot_sz);
+            return patch_std_zero_host_play(3, model, type, sb_file, boot_fw);
         case MODEL_ZENXFI3:
             /* The ZEN X-Fi3 uses the standard ____, hSst, pSay sections, patch after third
              * call in ____ section. Although sections names use the S variant, they are standard. */
-            return patch_std_zero_host_play(3, model, type, sb_file, boot, boot_sz);
+            return patch_std_zero_host_play(3, model, type, sb_file, boot_fw);
         case MODEL_ZENXFI2:
             /* The ZEN X-Fi2 has two types of firmware: recovery and normal.
              * Normal uses the standard ___, host, play sections and recovery only ____ */
@@ -355,7 +363,7 @@ static enum imx_error_t patch_firmware(enum imx_model_t model,
                 case VARIANT_ZENXFI2_RECOVERY:
                 case VARIANT_ZENXFI2_NAND:
                 case VARIANT_ZENXFI2_SD:
-                    return patch_std_zero_host_play(1, model, type, sb_file, boot, boot_sz);
+                    return patch_std_zero_host_play(1, model, type, sb_file, boot_fw);
                 default:
                     return IMX_DONT_KNOW_HOW_TO_PATCH;
             }
@@ -413,165 +421,240 @@ void dump_imx_dev_info(const char *prefix)
     }
 }
 
-enum imx_error_t mkimxboot(const char *infile, const char *bootfile,
-    const char *outfile, struct imx_option_t opt)
+/* find an entry into imx_sums which matches the MD5 sum of a file */
+static enum imx_error_t find_model_by_md5sum(uint8_t file_md5sum[16], int *md5_idx)
 {
-    /* Dump tables */
-    if(opt.fw_variant > VARIANT_COUNT) {
-        return IMX_ERROR;
-    }
-    dump_imx_dev_info("[INFO] ");
-    /* compute MD5 sum of the file */
-    uint8_t file_md5sum[16];
-    do
+    int i = 0;
+    while(i < NR_IMX_SUMS)
     {
-        FILE *f = fopen(infile, "rb");
-        if(f == NULL)
+        uint8_t md5[20];
+        if(strlen(imx_sums[i].md5sum) != 32)
         {
-            printf("[ERR] Cannot open input file\n");
-            return IMX_OPEN_ERROR;
+            printf("[INFO] Invalid MD5 sum in imx_sums\n");
+            return IMX_ERROR;
         }
-        fseek(f, 0, SEEK_END);
-        size_t sz = ftell(f);
-        fseek(f, 0, SEEK_SET);
-        void *buf = xmalloc(sz);
-        if(fread(buf, sz, 1, f) != 1)
+        for(int j = 0; j < 16; j++)
         {
-            fclose(f);
-            free(buf);
-            printf("[ERR] Cannot read file\n");
-            return IMX_READ_ERROR;
+            byte a, b;
+            if(convxdigit(imx_sums[i].md5sum[2 * j], &a) || convxdigit(imx_sums[i].md5sum[2 * j + 1], &b))
+            {
+                printf("[ERR][INTERNAL] Bad checksum format: %s\n", imx_sums[i].md5sum);
+                return IMX_ERROR;
+            }
+            md5[j] = (a << 4) | b;
         }
+        if(memcmp(file_md5sum, md5, 16) == 0)
+            break;
+        i++;
+    }
+    if(i == NR_IMX_SUMS)
+    {
+        printf("[ERR] MD5 sum doesn't match any known file\n");
+        return IMX_NO_MATCH;
+    }
+    *md5_idx = i;
+    return IMX_SUCCESS;
+}
+
+/* read a file to a buffer */
+static enum imx_error_t read_file(const char *file, void **buffer, size_t *size)
+{
+    FILE *f = fopen(file, "rb");
+    if(f == NULL)
+    {
+        printf("[ERR] Cannot open file '%s' for reading: %m\n", file);
+        return IMX_OPEN_ERROR;
+    }
+    fseek(f, 0, SEEK_END);
+    *size = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    *buffer = xmalloc(*size);
+    if(fread(*buffer, *size, 1, f) != 1)
+    {
+        free(*buffer);
+        fclose(f);
+        printf("[ERR] Cannot read file '%s': %m\n", file);
+        return IMX_READ_ERROR;
+    }
+    fclose(f);
+    return IMX_SUCCESS;
+}
+
+/* write a file from a buffer */
+static enum imx_error_t write_file(const char *file, void *buffer, size_t size)
+{
+    FILE *f = fopen(file, "wb");
+    if(f == NULL)
+    {
+        printf("[ERR] Cannot open file '%s' for writing: %m\n", file);
+        return IMX_OPEN_ERROR;
+    }
+    if(fwrite(buffer, size, 1, f) != 1)
+    {
+        fclose(f);
+        printf("[ERR] Cannot write file '%s': %m\n", file);
+        return IMX_WRITE_ERROR;
+    }
+    fclose(f);
+    return IMX_SUCCESS;
+}
+
+/* compute MD5 sum of a buffer */
+static enum imx_error_t compute_md5sum_buf(void *buf, size_t sz, uint8_t file_md5sum[16])
+{
+    md5_context ctx;
+    md5_starts(&ctx);
+    md5_update(&ctx, buf, sz);
+    md5_finish(&ctx, file_md5sum);
+    return IMX_SUCCESS;
+}
+
+/* compute MD5 of a file */
+static enum imx_error_t compute_md5sum(const char *file, uint8_t file_md5sum[16])
+{
+    FILE *f = fopen(file, "rb");
+    if(f == NULL)
+    {
+        printf("[ERR] Cannot open input file\n");
+        return IMX_OPEN_ERROR;
+    }
+    fseek(f, 0, SEEK_END);
+    size_t sz = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    void *buf = xmalloc(sz);
+    if(fread(buf, sz, 1, f) != 1)
+    {
         fclose(f);
-        md5_context ctx;
-        md5_starts(&ctx);
-        md5_update(&ctx, buf, sz);
-        md5_finish(&ctx, file_md5sum);
         free(buf);
-    }while(0);
+        printf("[ERR] Cannot read file\n");
+        return IMX_READ_ERROR;
+    }
+    fclose(f);
+    compute_md5sum_buf(buf, sz, file_md5sum);
+    free(buf);
+    return IMX_SUCCESS;
+}
+
+static enum imx_error_t load_sb_file(const char *file, int md5_idx,
+    struct imx_option_t opt, struct sb_file_t **sb_file)
+{
+    if(imx_sums[md5_idx].fw_variants[opt.fw_variant].size == 0)
+    {
+        printf("[ERR] Input file does not contain variant '%s'\n", imx_fw_variant[opt.fw_variant]);
+        return IMX_VARIANT_MISMATCH;
+    }
+    enum imx_model_t model = imx_sums[md5_idx].model;
+    enum sb_error_t err;
+    g_debug = opt.debug;
+    clear_keys();
+    add_keys(imx_models[model].keys, imx_models[model].nr_keys);
+    *sb_file = sb_read_file_ex(file, imx_sums[md5_idx].fw_variants[opt.fw_variant].offset,
+                              imx_sums[md5_idx].fw_variants[opt.fw_variant].size, false, NULL, &imx_printf, &err);
+    if(*sb_file == NULL)
+    {
+        clear_keys();
+        return IMX_FIRST_SB_ERROR + err;
+    }
+    return IMX_SUCCESS;
+}
+
+/* Load a rockbox firwmare from a buffer. Data is copied. */
+static enum imx_error_t rb_fw_load_buf(struct rb_fw_t *fw, uint8_t *buf, size_t sz,
+    enum imx_model_t model)
+{
+    if(sz < 8)
+    {
+        printf("[ERR] Bootloader file is too small to be valid\n");
+        return IMX_BOOT_INVALID;
+    }
+    /* check model name */
+    uint8_t *name = buf + 4;
+    if(memcmp(name, imx_models[model].rb_model_name, 4) != 0)
+    {
+        printf("[ERR] Bootloader model doesn't match found model for input file\n");
+        return IMX_BOOT_MISMATCH;
+    }
+    /* check checksum */
+    uint32_t sum = imx_models[model].rb_model_num;
+    for(int i = 8; i < sz; i++)
+        sum += buf[i];
+    if(sum != get_uint32be(buf))
+    {
+        printf("[ERR] Bootloader checksum mismatch\n");
+        return IMX_BOOT_CHECKSUM_ERROR;
+    }
+    fw->boot = memdup(buf + 8, sz - 8);
+    fw->boot_sz = sz - 8;
+    return IMX_SUCCESS;
+}
+
+/* load a rockbox firmware from a file. */
+static enum imx_error_t rb_fw_load(struct rb_fw_t *fw, const char *file,
+    enum imx_model_t model)
+{
+    void *buf;
+    size_t sz;
+    int ret = read_file(file, &buf, &sz);
+    if(ret == IMX_SUCCESS)
+    {
+        ret = rb_fw_load_buf(fw, buf, sz, model);
+        free(buf);
+    }
+    return ret;
+}
+
+/* free rockbox firmware */
+static void rb_fw_free(struct rb_fw_t *fw)
+{
+    free(fw->boot);
+    fw->boot = NULL;
+    fw->boot_sz = 0;
+}
+
+enum imx_error_t mkimxboot(const char *infile, const char *bootfile,
+    const char *outfile, struct imx_option_t opt)
+{
+    /* sanity check */
+    if(opt.fw_variant > VARIANT_COUNT)
+        return IMX_ERROR;
+    /* Dump tables */
+    dump_imx_dev_info("[INFO] ");
+    /* compute MD5 sum of the file */
+    uint8_t file_md5sum[16];
+    enum imx_error_t ret = compute_md5sum(infile, file_md5sum);
+    if(ret != IMX_SUCCESS)
+        return ret;
     printf("[INFO] MD5 sum of the file: ");
     print_hex(file_md5sum, 16, true);
     /* find model */
-    enum imx_model_t model;
     int md5_idx;
-    do
-    {
-        int i = 0;
-        while(i < NR_IMX_SUMS)
-        {
-            uint8_t md5[20];
-            if(strlen(imx_sums[i].md5sum) != 32)
-            {
-                printf("[INFO] Invalid MD5 sum in imx_sums\n");
-                return IMX_ERROR;
-            }
-            for(int j = 0; j < 16; j++)
-            {
-                byte a, b;
-                if(convxdigit(imx_sums[i].md5sum[2 * j], &a) || convxdigit(imx_sums[i].md5sum[2 * j + 1], &b))
-                {
-                    printf("[ERR][INTERNAL] Bad checksum format: %s\n", imx_sums[i].md5sum);
-                    return IMX_ERROR;
-                }
-                md5[j] = (a << 4) | b;
-            }
-            if(memcmp(file_md5sum, md5, 16) == 0)
-                break;
-            i++;
-        }
-        if(i == NR_IMX_SUMS)
-        {
-            printf("[ERR] MD5 sum doesn't match any known file\n");
-            return IMX_NO_MATCH;
-        }
-        model = imx_sums[i].model;
-        md5_idx = i;
-    }while(0);
+    ret = find_model_by_md5sum(file_md5sum, &md5_idx);
+    if(ret != IMX_SUCCESS)
+        return ret;
+    enum imx_model_t model = imx_sums[md5_idx].model;
     printf("[INFO] File is for model %d (%s, version %s)\n", model,
         imx_models[model].model_name, imx_sums[md5_idx].version);
     /* load rockbox file */
-    uint8_t *boot;
-    size_t boot_size;
-    do
-    {
-        FILE *f = fopen(bootfile, "rb");
-        if(f == NULL)
-        {
-            printf("[ERR] Cannot open boot file\n");
-            return IMX_OPEN_ERROR;
-        }
-        fseek(f, 0, SEEK_END);
-        boot_size = ftell(f);
-        fseek(f, 0, SEEK_SET);
-        boot = xmalloc(boot_size);
-        if(fread(boot, boot_size, 1, f) != 1)
-        {
-            free(boot);
-            fclose(f);
-            printf("[ERR] Cannot read boot file\n");
-            return IMX_READ_ERROR;
-        }
-        fclose(f);
-    }while(0);
-    /* Check boot file */
-    do
-    {
-        if(boot_size < 8)
-        {
-            printf("[ERR] Bootloader file is too small to be valid\n");
-            free(boot);
-            return IMX_BOOT_INVALID;
-        }
-        /* check model name */
-        uint8_t *name = boot + 4;
-        if(memcmp(name, imx_models[model].rb_model_name, 4) != 0)
-        {
-            printf("[ERR] Bootloader model doesn't match found model for input file\n");
-            free(boot);
-            return IMX_BOOT_MISMATCH;
-        }
-        /* check checksum */
-        uint32_t sum = imx_models[model].rb_model_num;
-        for(int i = 8; i < boot_size; i++)
-            sum += boot[i];
-        if(sum != get_uint32be(boot))
-        {
-            printf("[ERR] Bootloader checksum mismatch\n");
-            free(boot);
-            return IMX_BOOT_CHECKSUM_ERROR;
-        }
-    }while(0);
+    struct rb_fw_t boot_fw;
+    ret = rb_fw_load(&boot_fw, bootfile, model);
+    if(ret != IMX_SUCCESS)
+        return ret;
     /* load OF file */
     struct sb_file_t *sb_file;
-    do
+    ret = load_sb_file(infile, md5_idx, opt, &sb_file);
+    if(ret != IMX_SUCCESS)
     {
-        if(imx_sums[md5_idx].fw_variants[opt.fw_variant].size == 0)
-        {
-            printf("[ERR] Input file does not contain variant '%s'\n", imx_fw_variant[opt.fw_variant]);
-            free(boot);
-            return IMX_VARIANT_MISMATCH;
-        }
-        enum sb_error_t err;
-        g_debug = opt.debug;
-        clear_keys();
-        add_keys(imx_models[model].keys, imx_models[model].nr_keys);
-        sb_file = sb_read_file_ex(infile, imx_sums[md5_idx].fw_variants[opt.fw_variant].offset,
-            imx_sums[md5_idx].fw_variants[opt.fw_variant].size, false, NULL, &imx_printf, &err);
-        if(sb_file == NULL)
-        {
-            clear_keys();
-            free(boot);
-            return IMX_FIRST_SB_ERROR + err;
-        }
-    }while(0);
+        rb_fw_free(&boot_fw);
+        return ret;
+    }
     /* produce file */
-    enum imx_error_t ret = patch_firmware(model, opt.fw_variant, opt.output,
-        sb_file, boot + 8, boot_size - 8, opt.force_version);
+    ret = patch_firmware(model, opt.fw_variant, opt.output,
+        sb_file, boot_fw, opt.force_version);
     if(ret == IMX_SUCCESS)
         ret = sb_write_file(sb_file, outfile);
 
     clear_keys();
-    free(boot);
+    rb_fw_free(&boot_fw);
     sb_free(sb_file);
     return ret;
 }
@@ -579,78 +662,38 @@ enum imx_error_t mkimxboot(const char *infile, const char *bootfile,
 enum imx_error_t extract_firmware(const char *infile,
     enum imx_firmware_variant_t fw_variant, const char *outfile)
 {
-    /* Dump tables */
-    if(fw_variant > VARIANT_COUNT) {
+    /* sanity check */
+    if(fw_variant > VARIANT_COUNT)
         return IMX_ERROR;
-    }
+    /* dump tables */
     dump_imx_dev_info("[INFO] ");
     /* compute MD5 sum of the file */
+    void *buf;
+    size_t sz;
     uint8_t file_md5sum[16];
-    FILE *f = fopen(infile, "rb");
-    if(f == NULL)
-    {
-        printf("[ERR] Cannot open input file\n");
-        return IMX_OPEN_ERROR;
-    }
-    fseek(f, 0, SEEK_END);
-    size_t sz = ftell(f);
-    fseek(f, 0, SEEK_SET);
-    void *buf = xmalloc(sz);
-    if(fread(buf, sz, 1, f) != 1)
+    int ret = read_file(infile, &buf, &sz);
+    if(ret != IMX_SUCCESS)
+        return ret;
+    ret = compute_md5sum_buf(buf, sz, file_md5sum);
+    if(ret != IMX_SUCCESS)
     {
-        fclose(f);
         free(buf);
-        printf("[ERR] Cannot read file\n");
-        return IMX_READ_ERROR;
+        return ret;
     }
-    md5_context ctx;
-    md5_starts(&ctx);
-    md5_update(&ctx, buf, sz);
-    md5_finish(&ctx, file_md5sum);
-    fclose(f);
-    
     printf("[INFO] MD5 sum of the file: ");
     print_hex(file_md5sum, 16, true);
     /* find model */
-    enum imx_model_t model;
     int md5_idx;
-    do
+    ret = find_model_by_md5sum(file_md5sum, &md5_idx);
+    if(ret != IMX_SUCCESS)
     {
-        int i = 0;
-        while(i < NR_IMX_SUMS)
-        {
-            uint8_t md5[20];
-            if(strlen(imx_sums[i].md5sum) != 32)
-            {
-                printf("[INFO] Invalid MD5 sum in imx_sums\n");
-                return IMX_ERROR;
-            }
-            for(int j = 0; j < 16; j++)
-            {
-                byte a, b;
-                if(convxdigit(imx_sums[i].md5sum[2 * j], &a) || convxdigit(imx_sums[i].md5sum[2 * j + 1], &b))
-                {
-                    printf("[ERR][INTERNAL] Bad checksum format: %s\n", imx_sums[i].md5sum);
-                    free(buf);
-                    return IMX_ERROR;
-                }
-                md5[j] = (a << 4) | b;
-            }
-            if(memcmp(file_md5sum, md5, 16) == 0)
-                break;
-            i++;
-        }
-        if(i == NR_IMX_SUMS)
-        {
-            printf("[ERR] MD5 sum doesn't match any known file\n");
-            return IMX_NO_MATCH;
-        }
-        model = imx_sums[i].model;
-        md5_idx = i;
-    }while(0);
+        free(buf);
+        return ret;
+    }
+    enum imx_model_t model = imx_sums[md5_idx].model;
     printf("[INFO] File is for model %d (%s, version %s)\n", model,
         imx_models[model].model_name, imx_sums[md5_idx].version);
-
+    /* extract firmware */
     if(imx_sums[md5_idx].fw_variants[fw_variant].size == 0)
     {
         printf("[ERR] Input file does not contain variant '%s'\n", imx_fw_variant[fw_variant]);
@@ -658,23 +701,9 @@ enum imx_error_t extract_firmware(const char *infile,
         return IMX_VARIANT_MISMATCH;
     }
 
-    f = fopen(outfile, "wb");
-    if(f == NULL)
-    {
-        printf("[ERR] Cannot open input file\n");
-        free(buf);
-        return IMX_OPEN_ERROR;
-    }
-    enum imx_error_t ret = IMX_SUCCESS;
-
-    if(fwrite(buf + imx_sums[md5_idx].fw_variants[fw_variant].offset,
-            imx_sums[md5_idx].fw_variants[fw_variant].size, 1, f) != 1)
-    {
-        printf("[ERR] Cannot write file\n");
-        ret = IMX_ERROR;
-    }
-    fclose(f);
+    ret = write_file(outfile,
+        buf + imx_sums[md5_idx].fw_variants[fw_variant].offset,
+        imx_sums[md5_idx].fw_variants[fw_variant].size);
     free(buf);
-
     return ret;
 }
diff --git a/rbutil/mkimxboot/mkimxboot.h b/rbutil/mkimxboot/mkimxboot.h
index 748742f523..de564dc5d4 100644
--- a/rbutil/mkimxboot/mkimxboot.h
+++ b/rbutil/mkimxboot/mkimxboot.h
@@ -41,7 +41,8 @@ enum imx_error_t
     IMX_BOOT_CHECKSUM_ERROR = -7,
     IMX_DONT_KNOW_HOW_TO_PATCH = -8,
     IMX_VARIANT_MISMATCH = -9,
-    IMX_FIRST_SB_ERROR = -10,
+    IMX_WRITE_ERROR = -10,
+    IMX_FIRST_SB_ERROR = -11,
 };
 
 enum imx_output_type_t