Re: [PATCH v2 4/6] common: elf: add elf_open and elf_close

["Clément Leger" <cleger@kalray.eu>]

Hi Sascha,

----- On 28 Apr, 2020, at 08:39, Sascha Hauer s.hauer@pengutronix.de wrote:

> On Thu, Apr 23, 2020 at 10:17:09AM +0200, Clement Leger wrote:
>> When loading an elf file from a mtd device, this allows to parse the
>> header and load only the needed data according to the elf size. Without
>> that support, loading a elf file from a /dev/mtd would try to read the
>> entire partition.
>> 
>> Signed-off-by: Clement Leger <cleger@kalray.eu>
>> ---
>>  common/elf.c  | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++
>>  include/elf.h |  7 +++++
>>  2 files changed, 90 insertions(+)
>> 
>> diff --git a/common/elf.c b/common/elf.c
>> index 5534632b2..291f883cb 100644
>> --- a/common/elf.c
>> +++ b/common/elf.c
>> @@ -5,7 +5,12 @@
>>  
>>  #include <common.h>
>>  #include <elf.h>
>> +#include <errno.h>
>> +#include <fcntl.h>
>> +#include <libfile.h>
>>  #include <memory.h>
>> +#include <unistd.h>
>> +#include <linux/fs.h>
>>  
>>  struct elf_section {
>>  	struct list_head list;
>> @@ -158,3 +163,81 @@ void elf_release_image(struct elf_image *elf)
>>  
>>  	free(elf);
>>  }
>> +
>> +static u64 elf_get_size(struct elf_image *elf)
>> +{
>> +	u64 sh_size = elf_hdr_e_shentsize(elf, elf->buf) *
>> +		      elf_hdr_e_shnum(elf, elf->buf);
>> +
>> +	/*
>> +	 * The section header table is located at the end of the elf file thus
>> +	 * we can take the offset and add the size of this table to obtain the
>> +	 * file size.
>> +	 */
>> +	return elf_hdr_e_shoff(elf, elf->buf) + sh_size;
>> +}
>> +
>> +struct elf_image *elf_open(const char *filename)
>> +{
>> +	int fd, ret;
>> +	u64 size;
>> +	struct elf64_hdr hdr;
>> +	struct elf_image *elf;
>> +	ssize_t read_ret;
>> +
>> +	fd = open(filename, O_RDONLY);
>> +	if (fd < 0) {
>> +		printf("could not open: %s\n", errno_str());
>> +		return ERR_PTR(-errno);
>> +	}
>> +
>> +	if (read(fd, &hdr, sizeof(hdr)) < 0) {
>> +		printf("could not read elf header: %s\n", errno_str());
>> +		ret = -errno;
>> +		goto err_close_fd;
>> +	}
>> +
>> +	elf = xzalloc(sizeof(*elf));
>> +
>> +	ret = elf_check_init(elf, &hdr);
>> +	if (ret) {
>> +		ret = -errno;
>> +		goto err_free_elf;
>> +	}
>> +
>> +	size = elf_get_size(elf);
>> +
>> +	elf->buf = xmalloc(size);
> 
> As said before, please use malloc rather than one of the x-functions.
> The regular malloc can fail when we are out of memory and then you have
> a chance to fail gracefully.

Sorry, I understood that after and I have a v3 with this fix amongst other.
I also fixed bootm_load_os to load the existing elf file if any and modified
mips bootm accordingly. I will send it today.

Clément

> 
> Sascha
> 
> --
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