def get_value(ftype, value):
"""Get a value as a C expression
For integers this returns a byte-swapped (little-endian) hex string
For bytes this returns a hex string, e.g. 0x12
For strings this returns a literal string enclosed in quotes
For booleans this return 'true'
Args:
type: Data type (fdt_util)
value: Data value, as a string of bytes
"""
if ftype == fdt.TYPE_INT:
return '%#x' % fdt_util.fdt32_to_cpu(value)
elif ftype == fdt.TYPE_BYTE:
return '%#x' % tools.ToByte(value[0])
elif ftype == fdt.TYPE_STRING:
return '"%s"' % value
elif ftype == fdt.TYPE_BOOL:
return 'true'
elif ftype == fdt.TYPE_INT64:
return '%#x' % value
def MakeElf(elf_fname, text, data):
"""Make an elf file with the given data in a single section
The output file has a several section including '.text' and '.data',
containing the info provided in arguments.
Args:
elf_fname: Output filename
text: Text (code) to put in the file's .text section
data: Data to put in the file's .data section
"""
outdir = tempfile.mkdtemp(prefix='binman.elf.')
s_file = os.path.join(outdir, 'elf.S')
# Spilt the text into two parts so that we can make the entry point two
# bytes after the start of the text section
text_bytes1 = ['\t.byte\t%#x' % tools.ToByte(byte) for byte in text[:2]]
text_bytes2 = ['\t.byte\t%#x' % tools.ToByte(byte) for byte in text[2:]]
data_bytes = ['\t.byte\t%#x' % tools.ToByte(byte) for byte in data]
with open(s_file, 'w') as fd:
print(
'''/* Auto-generated C program to produce an ELF file for testing */
.section .text
.code32
.globl _start
.type _start, @function
%s
_start:
%s
.ident "comment"
.comm fred,8,4
.section .empty
.globl _empty
_empty:
.byte 1
.globl ernie
.data
.type ernie, @object
.size ernie, 4
ernie:
%s
''' % ('\n'.join(text_bytes1), '\n'.join(text_bytes2), '\n'.join(data_bytes)),
file=fd)
lds_file = os.path.join(outdir, 'elf.lds')
# Use a linker script to set the alignment and text address.
with open(lds_file, 'w') as fd:
print(
'''/* Auto-generated linker script to produce an ELF file for testing */
PHDRS
{
text PT_LOAD ;
data PT_LOAD ;
empty PT_LOAD FLAGS ( 6 ) ;
note PT_NOTE ;
}
SECTIONS
{
. = 0xfef20000;
ENTRY(_start)
.text . : SUBALIGN(0)
{
*(.text)
} :text
.data : {
*(.data)
} :data
_bss_start = .;
.empty : {
*(.empty)
} :empty
.note : {
*(.comment)
} :note
.bss _bss_start (OVERLAY) : {
*(.bss)
}
}
''',
file=fd)
# -static: Avoid requiring any shared libraries
# -nostdlib: Don't link with C library
# -Wl,--build-id=none: Don't generate a build ID, so that we just get the
# text section at the start
# -m32: Build for 32-bit x86
# -T...: Specifies the link script, which sets the start address
stdout = command.Output('cc', '-static', '-nostdlib',
'-Wl,--build-id=none', '-m32', '-T', lds_file,
'-o', elf_fname, s_file)
shutil.rmtree(outdir)