diff options
Diffstat (limited to 'mkubootenv/mkubootenv.c')
-rw-r--r-- | mkubootenv/mkubootenv.c | 330 |
1 files changed, 330 insertions, 0 deletions
diff --git a/mkubootenv/mkubootenv.c b/mkubootenv/mkubootenv.c new file mode 100644 index 0000000..8e49cbb --- /dev/null +++ b/mkubootenv/mkubootenv.c @@ -0,0 +1,330 @@ +/* + * mkubootenv.c + * + * Create a U-Boot environment image suitable for flashing. + * + * The input is a text file containing environment variable + * definitions in the format "name=value", separeated by newlines. + * + * The "environment" (output) is stored as a list of '\0' terminated + * "name=value" strings. The end of the list is marked by a double '\0'. + * + * The environment is preceeded by a 32 bit CRC over the data part. + * + * Copyright (c) 2009, Zurich University of Applied Sciences + * Copyright (c) 2009, Tobias Klauser <klto@zhaw.ch> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, + * MA 02110-1301, USA. + */ + +#include <stdlib.h> +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> + +#include <fcntl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mman.h> + +#include "crc32.h" + +#undef DEBUG + +#define CMD_NAME "mkubootenv" + +#define CRC32_SIZE sizeof(uint32_t) +/* minimum trailing null bytes */ +#define TRAILER_SIZE 2 + +#define err(fmt, args...) fprintf(stderr, "%s: Error: " fmt, CMD_NAME, ##args) +#define warn(fmt, args...) fprintf(stderr, "%s: Warning: " fmt, CMD_NAME, ##args) +#ifdef DEBUG +# define dbg(fmt, args...) fprintf(stdout, fmt, ##args) +#else +# define dbg(fmt, args...) +#endif + +/* file "object" */ +struct file { + const char *name; + int fd; + uint8_t *ptr; + size_t size; +}; + +static void usage_and_exit(int status) __attribute__((noreturn)); + +static inline void uboot_env_init_file(struct file *f) +{ + memset(f, 0, sizeof(struct file)); + f->ptr = MAP_FAILED; +} + +static int uboot_env_prepare_source(struct file *s) +{ + struct stat sbuf; + + s->fd = open(s->name, O_RDONLY); + if (s->fd < 0) { + err("Can't open source file '%s': %s\n", s->name, + strerror(errno)); + return EXIT_FAILURE; + } + + if (fstat(s->fd, &sbuf) < 0) { + err("Can't stat source file '%s': %s\n", s->name, + strerror(errno)); + close(s->fd); + return -1; + } + + s->ptr = mmap(NULL, sbuf.st_size, PROT_READ, MAP_SHARED, s->fd, 0); + if (s->ptr == MAP_FAILED) { + err("Can't mmap source image file '%s': %s\n", s->name, + strerror(errno)); + close(s->fd); + return -1; + } + + s->size = sbuf.st_size; + + return 0; +} + +static int uboot_env_prepare_target(struct file *t) +{ + t->fd = open(t->name, O_RDWR|O_CREAT|O_TRUNC, 0666); + if (t->fd < 0) { + err("Can't open target image file '%s': %s\n", t->name, + strerror(errno)); + return -1; + } + + /* + * seek to the end of the target file to write a byte, so we have the + * whole target image size mapped for writing + */ + if (lseek(t->fd, t->size - 1, SEEK_SET) < 0) { + err("Can't seek in target image file '%s': %s\n", t->name, + strerror(errno)); + close(t->fd); + return -1; + } + + if (write(t->fd, "", 1) < 0) { + err("Can't write to target image file '%s': %s\n", t->name, + strerror(errno)); + close(t->fd); + return -1; + } + + t->ptr = mmap(NULL, t->size, PROT_READ|PROT_WRITE, MAP_SHARED, t->fd, 0); + if (t->ptr == MAP_FAILED) { + err("Can't mmap target image file '%s': %s\n", t->name, + strerror(errno)); + close(t->fd); + return -1; + } + + return 0; +} + +static void uboot_env_cleanup_file(struct file *f) +{ + if (f->ptr != MAP_FAILED) + munmap(f->ptr, f->size); + if (f->fd > 0) + close(f->fd); +} + +static void uboot_env_to_img(struct file *s, struct file *t) +{ + uint8_t *p, *q, *end; + uint32_t *crc; + + dbg("source file (env): %s\n", s->name); + dbg("target image file (bin): %s\n", t->name); + dbg("target size: %zd\n", t->size); + + /* CRC32 placeholder, will be filled later */ + end = t->ptr + CRC32_SIZE; + for (p = t->ptr; p < end; p++) + *p = 0; + + /* copy the source file, replacing \n by \0 */ + end = s->ptr + s->size; + for (q = s->ptr; q < end; q++, p++) + *p = (*q == '\n') ? '\0' : *q; + + /* trailer */ + end = s->ptr + t->size; + for (q = s->ptr + s->size; q < end; q++) + *p = 0; + + /* now for the real CRC32 */ + crc = (uint32_t *) t->ptr; + *crc = crc32(0, t->ptr + CRC32_SIZE, t->size - CRC32_SIZE); +} + +static void uboot_img_to_env(struct file *s, struct file *t) +{ + uint8_t *p, *q, *end; + uint32_t *crc; + + dbg("source file (bin): %s\n", s->name); + dbg("target image file (env): %s\n", t->name); + dbg("target size: %zd\n", t->size); + + /* check CRC */ + crc = (uint32_t *) s->ptr; + if (*crc != crc32(0, s->ptr + CRC32_SIZE, s->size - CRC32_SIZE)) + warn("source image with bad CRC\n"); + + p = t->ptr; + end = s->ptr + CRC32_SIZE + t->size; + for (q = s->ptr + CRC32_SIZE; q < end; p++, q++) + *p = (*q == '\0') ? '\n' : *q; +} + +static void usage_and_exit(int status) +{ + printf("usage: mkubootenv [-s <size>] <source file> <target file>\n" + " -s <size> set size of the target image file to <size> bytes. If <size> is\n" + " bigger than the source file, the target image gets padded with null\n" + " bytes. If <size> is smaller than the source file, an error is emitted.\n" + " -r reverse operation: get plaintext env file (target) from binary image\n" + " file (source)\n"); + exit(status); +} + +int main(int argc, char **argv) +{ + int i; + int status = EXIT_FAILURE; + ssize_t img_size = -1; + bool reverse = false; + struct file s, t; /* source and target file */ + + if (argc < 2) + usage_and_exit(EXIT_FAILURE); + + /* parse commandline options */ + for (i = 1; (i + 1 < argc) && (argv[i][0] == '-'); i++) { + switch (argv[i][1]) { + case 's': { + char *opt = argv[++i]; + + if (strlen(opt) > 2 && opt[0] == '0' && + (opt[1] == 'x' || opt[1] == 'X')) { + img_size = strtol(opt, NULL, 16); + } else { + img_size = strtol(opt, NULL, 10); + + if (img_size <= 0) { + err("Invalid target image size: %zd. Must be greater than 0.\n", img_size); + exit(EXIT_FAILURE); + } + } + break; + } + case 'r': + reverse = true; + break; + case 'h': + status = EXIT_SUCCESS; + /* fall through */ + default: + usage_and_exit(status); + break; + } + } + + /* we expect two filenames */ + if (i + 2 > argc) + usage_and_exit(EXIT_FAILURE); + + if (reverse && img_size >= 0) + warn("Image size specified in reverse mode will be ignored\n"); + + uboot_env_init_file(&s); + uboot_env_init_file(&t); + s.name = argv[i]; + t.name = argv[i+1]; + + if (uboot_env_prepare_source(&s)) + exit(EXIT_FAILURE); + + if (!reverse) { + ssize_t min_img_size = CRC32_SIZE + s.size + TRAILER_SIZE; + + /* TODO: Check source file format: + * var=value\n + */ + + /* + * check whether the size hasn't been set or whether the source file + + * CRC + trailer fits into the specified size. + */ + if (img_size < 0) + img_size = min_img_size; + else if (img_size < min_img_size) { + err("Specified size (%zd) is too small for the source file to " + "fit into. Must be at least %zd bytes.\n", + img_size, min_img_size); + goto cleanup_source; + } + + t.size = img_size; + if (uboot_env_prepare_target(&t)) + goto cleanup_source; + + uboot_env_to_img(&s, &t); + } else { + uint8_t *p; + uint8_t *end; + bool found_data_end = false; + + /* get the length of the data part */ + end = s.ptr + CRC32_SIZE + s.size; + for (p = s.ptr + CRC32_SIZE; (p < end - 1) && (!found_data_end); p++) { + /* two null bytes mark the end of the data section */ + if (*p == '\0' && *(p + 1) == '\0') + found_data_end = true; + } + + if (!found_data_end) + warn("No end of list delimiter found in source file\n"); + + /* calculate the plain text file size */ + t.size = p - (s.ptr + CRC32_SIZE); + if (uboot_env_prepare_target(&t)) + goto cleanup_source; + + uboot_img_to_env(&s, &t); + } + + status = EXIT_SUCCESS; + + uboot_env_cleanup_file(&t); +cleanup_source: + uboot_env_cleanup_file(&s); + + exit(status); +} |