util: bsp-tool: extract bootstrap exec constants and store them in the bsp image

util/lib/elf.py

@@ -0,0 +1,102 @@
+from enum import Enum, Flag
+import struct
+
+class ELFPType(Enum):
+    NULL = 0
+    LOAD = 1
+    DYNAMIC = 2
+    INTERP = 3
+    NOTE = 4
+    SHLIB = 5
+    PHDR = 6
+    TLS = 7
+
+
+class ELFPFlag(Flag):
+    NONE = 0
+    EXEC = 1
+    WRITE = 2
+    READ = 4
+
+
+class ELFEndian(Enum):
+    LITTLE = 1
+    BIG = 2
+
+
+class ELF64Phdr:
+    def __init__(self):
+        self.type = ELFPType.NULL
+        self.flags = 0
+        self.offset = 0
+        self.vaddr = 0
+        self.paddr = 0
+        self.filesz = 0
+        self.memsz = 0
+        self.align = 0
+
+        return
+
+    def parse(self, buf, endian):
+        endian_marker = '>' if endian == ELFEndian.BIG else '<'
+        entry = struct.unpack('{}IIQQQQQQ'.format(endian_marker), buf)
+
+        self.type = ELFPType(entry[0])
+        self.flags = ELFPFlag.NONE
+        self.offset = entry[2]
+        self.vaddr = entry[3]
+        self.paddr = entry[4]
+        self.filesz = entry[5]
+        self.memsz = entry[6]
+        self.align = entry[7]
+
+        if entry[1] & ELFPFlag.READ.value: self.flags |= ELFPFlag.READ
+        if entry[1] & ELFPFlag.WRITE.value: self.flags |= ELFPFlag.WRITE
+        if entry[1] & ELFPFlag.EXEC.value: self.flags |= ELFPFlag.EXEC
+
+
+class ELF64Image:
+    def __init__(self):
+        self.ph_list = []
+        self.text = None
+        self.data = None
+        self.entry = None
+
+    def load(self, path):
+        f = open(path, mode='rb')
+        ident_bytes = f.read(16)
+
+        ident = struct.unpack('BBBBBBBBBBBBBBBB', ident_bytes)
+
+        if ident[0] != 0x7F or ident[1] != ord('E') or ident[2] != ord('L') or ident[3] != ord('F'):
+            f.close()
+            return -1
+
+        endian = ELFEndian(ident[5])
+        endian_marker = '>' if endian == ELFEndian.BIG else '<'
+
+        hdr_bytes = f.read(48)
+        hdr = struct.unpack('{}HHIQQQIHHHHHH'.format(endian_marker), hdr_bytes)
+
+        self.entry = hdr[3]
+        phoff = hdr[4]
+        phnum = hdr[9]
+        phentsize = hdr[8]
+
+        for i in range(0, phnum):
+            f.seek(phoff + (i * phentsize))
+            phdr_bytes = f.read(phentsize)
+
+            phdr = ELF64Phdr()
+            phdr.parse(phdr_bytes, endian)
+
+            if phdr.flags == ELFPFlag.READ | ELFPFlag.EXEC:
+                self.text = phdr
+            if phdr.flags == ELFPFlag.READ | ELFPFlag.WRITE:
+                self.data = phdr
+
+            self.ph_list.append(phdr)
+
+        f.close()
+        return 0
+