Add an optional alias list to SYSCALLS.TXT

This patch adds an optional alias list to SYSCALLS.TXT.  It is used to
create aliases for a syscall.  For x86-64, lseek64 is an alias for lseek.

Change-Id: Icb11fd2bb461ea4f5f0a26bfc585471d7d7cc468
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>

libc/SYSCALLS.TXT

@@ -2,7 +2,7 @@
 #
 # Each non-blank, non-comment line has the following format:
 #
-# return_type func_name[:syscall_name[:socketcall_id]]([parameter_list]) arch_list
+# return_type func_name[|alias_list][:syscall_name[:socketcall_id]]([parameter_list]) arch_list
 #
 # where:
 #       arch_list ::= "all" | "custom" | arch+
@@ -13,6 +13,8 @@
 #        the exported function name (example: the exit syscall is implemented by the _exit()
 #        function, which is not the same as the standard C exit() function which calls it)
 #
+#      - alias_list is optional comma separated list of function aliases.
+#
 #      - The call_id parameter, given that func_name and syscall_name have
 #        been provided, allows the user to specify dispatch style syscalls.
 #        For example, socket() syscall on i386 actually becomes:
@@ -109,7 +111,8 @@ int         __open:open(const char*, int, mode_t)  all
 int         __openat:openat(int, const char*, int, mode_t) all
 int         close(int)                      all
 int         creat(const char*, mode_t)       custom
-off_t       lseek(int, off_t, int)           all
+off_t       lseek(int, off_t, int)           arm,x86,mips
+off_t       lseek|lseek64(int, off_t, int)   x86_64
 int         __llseek:_llseek(int, unsigned long, unsigned long, off64_t*, int)  arm,x86,mips
 pid_t       getpid()    all
 void*       mmap(void*, size_t, int, int, int, long)  x86_64

libc/arch-x86_64/syscalls/lseek.S

@@ -15,3 +15,6 @@ ENTRY(lseek)
 1:
     ret
 END(lseek)
+
+    .globl _C_LABEL(lseek64)
+    .equ _C_LABEL(lseek64), _C_LABEL(lseek)

libc/tools/bionic_utils.py

@@ -49,7 +49,7 @@ class SysCallsTxtParser:
         """ parse a syscall spec line.
 
         line processing, format is
-           return type    func_name[:syscall_name[:socketcall_id]] ( [paramlist] )   architecture_list
+           return type    func_name[|alias_list][:syscall_name[:socketcall_id]] ( [paramlist] ) architecture_list
         """
         pos_lparen = line.find('(')
         E          = self.E
@@ -93,6 +93,17 @@ class SysCallsTxtParser:
                 socketcall_id = int(syscall_func[pos_colon2+1:])
                 syscall_func = syscall_func[:pos_colon]
 
+        alias_delim = syscall_func.find('|')
+        if alias_delim > 0:
+            alias_list = syscall_func[alias_delim+1:].strip()
+            syscall_func = syscall_func[:alias_delim]
+            alias_delim = syscall_name.find('|')
+            if alias_delim > 0:
+                syscall_name = syscall_name[:alias_delim]
+            syscall_aliases = string.split(alias_list, ',')
+        else:
+            syscall_aliases = []
+
         if pos_rparen > pos_lparen+1:
             syscall_params = line[pos_lparen+1:pos_rparen].split(',')
             params         = string.join(syscall_params,',')
@@ -103,6 +114,7 @@ class SysCallsTxtParser:
         t = {
               "name"    : syscall_name,
               "func"    : syscall_func,
+              "aliases" : syscall_aliases,
               "params"  : syscall_params,
               "decl"    : "%-15s  %s (%s);" % (return_type, syscall_func, params),
               "socketcall_id" : socketcall_id

libc/tools/gensyscalls.py

@@ -37,6 +37,10 @@ syscall_stub_header = """/* autogenerated by gensyscalls.py */
 ENTRY(%(fname)s)
 """
 
+function_alias = """
+    .globl _C_LABEL(%(alias)s)
+    .equ _C_LABEL(%(alias)s), _C_LABEL(%(fname)s)
+"""
 
 #
 # x86 assembler templates for each syscall stub
@@ -210,7 +214,7 @@ class State:
         self.other_files = []
         self.syscalls = []
 
-    def x86_64_genstub(self, fname, numparams, idname):
+    def x86_64_genstub(self, fname, numparams, idname, aliases):
         t = { "fname"  : fname, "idname" : idname }
 
         result = syscall_stub_header % t
@@ -219,6 +223,10 @@ class State:
             result += "    movq    %rcx, %r10\n"
 
         result += x86_64_call % t
+        for alias in aliases:
+            t = { "fname" : fname, "alias" : alias }
+            result += function_alias % t
+
         return result
 
     def x86_genstub(self, fname, numparams, idname):
@@ -301,6 +309,7 @@ class State:
 
         for t in self.syscalls:
             syscall_func   = t["func"]
+            syscall_aliases = t["aliases"]
             syscall_params = t["params"]
             syscall_name   = t["name"]
             __NR_name = make__NR_name(t["name"])
@@ -324,7 +333,7 @@ class State:
 
             if t.has_key("x86_64"):
                 num_regs = count_generic_param_registers64(syscall_params)
-                t["asm-x86_64"] = self.x86_64_genstub(syscall_func, num_regs, __NR_name)
+                t["asm-x86_64"] = self.x86_64_genstub(syscall_func, num_regs, __NR_name, syscall_aliases)
 
     # Scan a Linux kernel asm/unistd.h file containing __NR_* constants
     # and write out equivalent SYS_* constants for glibc source compatibility.