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platform_bionic/libc/tools/gensyscalls.py
Elliott Hughes 9aceab5015 Use the kernel's MAX_ERRNO in the syscall stubs. 
Bug: http://code.google.com/p/android/issues/detail?id=53104
Change-Id: Iaabf7025b153e96dc5eca231a33a32d4cb7d8116
2013-03-12 17:43:58 -07:00

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Python
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#!/usr/bin/python
#
# this tool is used to generate the syscall assembler templates
# to be placed into arch-{arm,x86,mips}/syscalls, as well as the content
# of arch-{arm,x86,mips}/linux/_syscalls.h
#
import sys, os.path, glob, re, commands, filecmp, shutil
import getpass
from bionic_utils import *
# get the root Bionic directory, simply this script's dirname
#
bionic_root = find_bionic_root()
if not bionic_root:
print "could not find the Bionic root directory. aborting"
sys.exit(1)
if bionic_root[-1] != '/':
bionic_root += "/"
print "bionic_root is %s" % bionic_root
# temp directory where we store all intermediate files
bionic_temp = "/tmp/bionic_gensyscalls/"
# all architectures, update as you see fit
all_archs = [ "arm", "mips", "x86" ]
def make_dir( path ):
path = os.path.abspath(path)
if not os.path.exists(path):
parent = os.path.dirname(path)
if parent:
make_dir(parent)
os.mkdir(path)
def create_file( relpath ):
dir = os.path.dirname( bionic_temp + relpath )
make_dir(dir)
return open( bionic_temp + relpath, "w" )
#
# x86 assembler templates for each syscall stub
#
x86_header = """/* autogenerated by gensyscalls.py */
#include <linux/err.h>
#include <machine/asm.h>
#include <sys/linux-syscalls.h>
ENTRY(%(fname)s)
"""
x86_registers = [ "%ebx", "%ecx", "%edx", "%esi", "%edi", "%ebp" ]
x86_call = """ movl $%(idname)s, %%eax
int $0x80
cmpl $-MAX_ERRNO, %%eax
jb 1f
negl %%eax
pushl %%eax
call __set_errno
addl $4, %%esp
orl $-1, %%eax
1:
"""
x86_return = """ ret
END(%(fname)s)
"""
#
# ARM assembler templates for each syscall stub
#
arm_header = """/* autogenerated by gensyscalls.py */
#include <linux/err.h>
#include <machine/asm.h>
#include <sys/linux-syscalls.h>
ENTRY(%(fname)s)
"""
arm_eabi_call_default = arm_header + """\
mov ip, r7
ldr r7, =%(idname)s
swi #0
mov r7, ip
cmn r0, #(MAX_ERRNO + 1)
bxls lr
neg r0, r0
b __set_errno
END(%(fname)s)
"""
arm_eabi_call_long = arm_header + """\
mov ip, sp
.save {r4, r5, r6, r7}
stmfd sp!, {r4, r5, r6, r7}
ldmfd ip, {r4, r5, r6}
ldr r7, =%(idname)s
swi #0
ldmfd sp!, {r4, r5, r6, r7}
cmn r0, #(MAX_ERRNO + 1)
bxls lr
neg r0, r0
b __set_errno
END(%(fname)s)
"""
#
# mips assembler templates for each syscall stub
#
mips_call = """/* autogenerated by gensyscalls.py */
#include <sys/linux-syscalls.h>
.text
.globl %(fname)s
.align 4
.ent %(fname)s
%(fname)s:
.set noreorder
.cpload $t9
li $v0, %(idname)s
syscall
bnez $a3, 1f
move $a0, $v0
j $ra
nop
1:
la $t9,__set_errno
j $t9
nop
.set reorder
.end %(fname)s
"""
def param_uses_64bits(param):
"""Returns True iff a syscall parameter description corresponds
to a 64-bit type."""
param = param.strip()
# First, check that the param type begins with one of the known
# 64-bit types.
if not ( \
param.startswith("int64_t") or param.startswith("uint64_t") or \
param.startswith("loff_t") or param.startswith("off64_t") or \
param.startswith("long long") or param.startswith("unsigned long long") or
param.startswith("signed long long") ):
return False
# Second, check that there is no pointer type here
if param.find("*") >= 0:
return False
# Ok
return True
def count_arm_param_registers(params):
"""This function is used to count the number of register used
to pass parameters when invoking an ARM system call.
This is because the ARM EABI mandates that 64-bit quantities
must be passed in an even+odd register pair. So, for example,
something like:
foo(int fd, off64_t pos)
would actually need 4 registers:
r0 -> int
r1 -> unused
r2-r3 -> pos
"""
count = 0
for param in params:
if param_uses_64bits(param):
if (count & 1) != 0:
count += 1
count += 2
else:
count += 1
return count
def count_generic_param_registers(params):
count = 0
for param in params:
if param_uses_64bits(param):
count += 2
else:
count += 1
return count
class State:
def __init__(self):
self.old_stubs = []
self.new_stubs = []
self.other_files = []
self.syscalls = []
def x86_genstub(self, fname, numparams, idname):
t = { "fname" : fname,
"idname" : idname }
result = x86_header % t
stack_bias = 4
for r in range(numparams):
result += " pushl " + x86_registers[r] + "\n"
stack_bias += 4
for r in range(numparams):
result += " mov %d(%%esp), %s" % (stack_bias+r*4, x86_registers[r]) + "\n"
result += x86_call % t
for r in range(numparams):
result += " popl " + x86_registers[numparams-r-1] + "\n"
result += x86_return % t
return result
def x86_genstub_cid(self, fname, numparams, idname, cid):
# We'll ignore numparams here because in reality, if there is a
# dispatch call (like a socketcall syscall) there are actually
# only 2 arguments to the syscall and 2 regs we have to save:
# %ebx <--- Argument 1 - The call id of the needed vectored
# syscall (socket, bind, recv, etc)
# %ecx <--- Argument 2 - Pointer to the rest of the arguments
# from the original function called (socket())
t = { "fname" : fname,
"idname" : idname }
result = x86_header % t
stack_bias = 4
# save the regs we need
result += " pushl %ebx" + "\n"
stack_bias += 4
result += " pushl %ecx" + "\n"
stack_bias += 4
# set the call id (%ebx)
result += " mov $%d, %%ebx" % (cid) + "\n"
# set the pointer to the rest of the args into %ecx
result += " mov %esp, %ecx" + "\n"
result += " addl $%d, %%ecx" % (stack_bias) + "\n"
# now do the syscall code itself
result += x86_call % t
# now restore the saved regs
result += " popl %ecx" + "\n"
result += " popl %ebx" + "\n"
# epilog
result += x86_return % t
return result
def arm_eabi_genstub(self,fname, flags, idname):
t = { "fname" : fname,
"idname" : idname }
if flags:
numargs = int(flags)
if numargs > 4:
return arm_eabi_call_long % t
return arm_eabi_call_default % t
def mips_genstub(self,fname, idname):
t = { "fname" : fname,
"idname" : idname }
return mips_call % t
def process_file(self,input):
parser = SysCallsTxtParser()
parser.parse_file(input)
self.syscalls = parser.syscalls
parser = None
for t in self.syscalls:
syscall_func = t["func"]
syscall_params = t["params"]
syscall_name = t["name"]
if t["common"] >= 0 or t["armid"] >= 0:
num_regs = count_arm_param_registers(syscall_params)
t["asm-arm"] = self.arm_eabi_genstub(syscall_func,num_regs,"__NR_"+syscall_name)
if t["common"] >= 0 or t["x86id"] >= 0:
num_regs = count_generic_param_registers(syscall_params)
if t["cid"] >= 0:
t["asm-x86"] = self.x86_genstub_cid(syscall_func, num_regs, "__NR_"+syscall_name, t["cid"])
else:
t["asm-x86"] = self.x86_genstub(syscall_func, num_regs, "__NR_"+syscall_name)
elif t["cid"] >= 0:
E("cid for dispatch syscalls is only supported for x86 in "
"'%s'" % syscall_name)
return
if t["common"] >= 0 or t["mipsid"] >= 0:
t["asm-mips"] = self.mips_genstub(syscall_func,"__NR_"+syscall_name)
def gen_NR_syscall(self,fp,name,id):
fp.write( "#define __NR_%-25s (__NR_SYSCALL_BASE + %d)\n" % (name,id) )
# now dump the content of linux-syscalls.h
def gen_linux_syscalls_h(self):
path = "include/sys/linux-syscalls.h"
D( "generating "+path )
fp = create_file( path )
fp.write( "/* auto-generated by gensyscalls.py, do not touch */\n" )
fp.write( "#ifndef _BIONIC_LINUX_SYSCALLS_H_\n" )
fp.write( "#define _BIONIC_LINUX_SYSCALLS_H_\n\n" )
fp.write( "#if !defined __ASM_ARM_UNISTD_H && !defined __ASM_I386_UNISTD_H && !defined __ASM_MIPS_UNISTD_H\n" )
fp.write( "#if defined __arm__ && !defined __ARM_EABI__ && !defined __thumb__\n" )
fp.write( " # define __NR_SYSCALL_BASE 0x900000\n" )
fp.write( "#elif defined(__mips__)\n" )
fp.write( " # define __NR_SYSCALL_BASE 4000\n" )
fp.write( "#else\n" )
fp.write( " # define __NR_SYSCALL_BASE 0\n" )
fp.write( "#endif\n\n" )
# first, all common syscalls
for sc in sorted(self.syscalls,key=lambda x:x["common"]):
sc_id = sc["common"]
sc_name = sc["name"]
if sc_id >= 0:
self.gen_NR_syscall( fp, sc_name, sc_id )
# now, all arm-specific syscalls
fp.write( "\n#ifdef __arm__\n" );
for sc in self.syscalls:
sc_id = sc["armid"]
sc_name = sc["name"]
if sc_id >= 0:
self.gen_NR_syscall( fp, sc_name, sc_id )
fp.write( "#endif\n" );
gen_syscalls = {}
# finally, all i386-specific syscalls
fp.write( "\n#ifdef __i386__\n" );
for sc in sorted(self.syscalls,key=lambda x:x["x86id"]):
sc_id = sc["x86id"]
sc_name = sc["name"]
if sc_id >= 0 and sc_name not in gen_syscalls:
self.gen_NR_syscall( fp, sc_name, sc_id )
gen_syscalls[sc_name] = True
fp.write( "#endif\n" );
# all mips-specific syscalls
fp.write( "\n#ifdef __mips__\n" );
for sc in sorted(self.syscalls,key=lambda x:x["mipsid"]):
sc_id = sc["mipsid"]
if sc_id >= 0:
self.gen_NR_syscall( fp, sc["name"], sc_id )
fp.write( "#endif\n" );
fp.write( "\n#endif\n" )
fp.write( "\n#endif /* _BIONIC_LINUX_SYSCALLS_H_ */\n" );
fp.close()
self.other_files.append( path )
# now dump the contents of syscalls.mk
def gen_arch_syscalls_mk(self, arch):
path = "arch-%s/syscalls.mk" % arch
D( "generating "+path )
fp = create_file( path )
fp.write( "# auto-generated by gensyscalls.py, do not touch\n" )
fp.write( "syscall_src := \n" )
arch_test = {
"arm": lambda x: x.has_key("asm-arm"),
"x86": lambda x: x.has_key("asm-x86"),
"mips": lambda x: x.has_key("asm-mips")
}
for sc in self.syscalls:
if arch_test[arch](sc):
fp.write("syscall_src += arch-%s/syscalls/%s.S\n" %
(arch, sc["func"]))
fp.close()
self.other_files.append( path )
# now generate each syscall stub
def gen_syscall_stubs(self):
for sc in self.syscalls:
if sc.has_key("asm-arm") and 'arm' in all_archs:
fname = "arch-arm/syscalls/%s.S" % sc["func"]
D2( ">>> generating "+fname )
fp = create_file( fname )
fp.write(sc["asm-arm"])
fp.close()
self.new_stubs.append( fname )
if sc.has_key("asm-x86") and 'x86' in all_archs:
fname = "arch-x86/syscalls/%s.S" % sc["func"]
D2( ">>> generating "+fname )
fp = create_file( fname )
fp.write(sc["asm-x86"])
fp.close()
self.new_stubs.append( fname )
if sc.has_key("asm-mips") and 'mips' in all_archs:
fname = "arch-mips/syscalls/%s.S" % sc["func"]
D2( ">>> generating "+fname )
fp = create_file( fname )
fp.write(sc["asm-mips"])
fp.close()
self.new_stubs.append( fname )
def regenerate(self):
D( "scanning for existing architecture-specific stub files" )
bionic_root_len = len(bionic_root)
for arch in all_archs:
arch_path = bionic_root + "arch-" + arch
D( "scanning " + arch_path )
files = glob.glob( arch_path + "/syscalls/*.S" )
for f in files:
self.old_stubs.append( f[bionic_root_len:] )
D( "found %d stub files" % len(self.old_stubs) )
if not os.path.exists( bionic_temp ):
D( "creating %s" % bionic_temp )
make_dir( bionic_temp )
D( "re-generating stubs and support files" )
self.gen_linux_syscalls_h()
for arch in all_archs:
self.gen_arch_syscalls_mk(arch)
self.gen_syscall_stubs()
D( "comparing files" )
adds = []
edits = []
for stub in self.new_stubs + self.other_files:
if not os.path.exists( bionic_root + stub ):
# new file, git add it
D( "new file: " + stub)
adds.append( bionic_root + stub )
shutil.copyfile( bionic_temp + stub, bionic_root + stub )
elif not filecmp.cmp( bionic_temp + stub, bionic_root + stub ):
D( "changed file: " + stub)
edits.append( stub )
deletes = []
for stub in self.old_stubs:
if not stub in self.new_stubs:
D( "deleted file: " + stub)
deletes.append( bionic_root + stub )
if adds:
commands.getoutput("git add " + " ".join(adds))
if deletes:
commands.getoutput("git rm " + " ".join(deletes))
if edits:
for file in edits:
shutil.copyfile( bionic_temp + file, bionic_root + file )
commands.getoutput("git add " +
" ".join((bionic_root + file) for file in edits))
commands.getoutput("git add %s%s" % (bionic_root,"SYSCALLS.TXT"))
if (not adds) and (not deletes) and (not edits):
D("no changes detected!")
else:
D("ready to go!!")
D_setlevel(1)
state = State()
state.process_file(bionic_root+"SYSCALLS.TXT")
state.regenerate()
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