Detect armv7l hard-float ABI for manylinux2014

PEP 599 defines manylinux2014 armv7l to be compatible with centos7 altarch armv7 i.e. armhf using the gnueabihf ABI

src/pip/_internal/pep425tags.py

@@ -164,6 +164,32 @@ def get_platform():
  return result
 
 
+def is_linux_armhf():
+ # type: () -> bool
+ if get_platform() != "linux_armv7l":
+ return False
+ # hard-float ABI can be detected from the ELF header of the running
+ # process
+ try:
+ with open(sys.executable, 'rb') as f:
+ elf_header_raw = f.read(40) # read 40 first bytes of ELF header
+ except (IOError, OSError, TypeError):
+ return False
+ if elf_header_raw is None or len(elf_header_raw) < 40:
+ return False
+ if isinstance(elf_header_raw, str):
+ elf_header = [ord(c) for c in elf_header_raw]
+ else:
+ elf_header = [b for b in elf_header_raw]
+ result = elf_header[0:4] == [0x7f, 0x45, 0x4c, 0x46] # ELF magic number
+ result &= elf_header[4:5] == [1] # 32-bit ELF
+ result &= elf_header[5:6] == [1] # little-endian
+ result &= elf_header[18:20] == [0x28, 0] # ARM machine
+ result &= elf_header[39:40] == [5] # ARM EABIv5
+ result &= (elf_header[37:38][0] & 4) == 4 # EF_ARM_ABI_FLOAT_HARD
+ return result
+
+
 def is_manylinux1_compatible():
  # type: () -> bool
  # Only Linux, and only x86-64 / i686
@@ -202,10 +228,16 @@ def is_manylinux2010_compatible():
 
 def is_manylinux2014_compatible():
  # type: () -> bool
- # Only Linux and only x86-64, i686, aarch64, armv7l, ppc64, ppc64le, s390x
- if get_platform() not in {"linux_x86_64", "linux_i686", "linux_aarch64",
- "linux_armv7l", "linux_ppc64", "linux_ppc64le",
- "linux_s390x"}:
+ # Only Linux, and only supported architectures
+ platform = get_platform()
+ if platform not in {"linux_x86_64", "linux_i686", "linux_aarch64",
+ "linux_armv7l", "linux_ppc64", "linux_ppc64le",
+ "linux_s390x"}:
+ return False
+
+ # check for hard-float ABI in case we're running linux_armv7l not to
+ # install hard-float ABI wheel in a soft-float ABI environment
+ if platform == "linux_armv7l" and not is_linux_armhf():
  return False
 
  # Check for presence of _manylinux module