296 lines
7.5 KiB
Awk
296 lines
7.5 KiB
Awk
# Copyright 2011 The Go Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style
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# license that can be found in the LICENSE file.
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# This AWK script reads a Go file with comments describing syscall
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# functions and the C routines they map to. It generates the Go code
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# which calls the C routines.
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# The syscall functins are marked by lines beginning with "//sys" and
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# read like func declarations if //sys is replaced by func, but:
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# * The parameter lists must give a name for each argument.
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# This includes return parameters.
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# * The parameter lists must give a type for each argument:
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# the (x, y, z int) shorthand is not allowed.
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# * If the return parameter is an error, it must be named err.
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# A line beginning with //sysnb is like //sys, except that the
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# goroutine will not be suspended during the execution of the library
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# call. This must only be used for library calls which can never
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# block, as otherwise the library call could cause all goroutines to
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# hang.
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# After the //sys or //sysnb line comes a second line which describes
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# the C function. The name must be the name of the function in the C
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# library, and may be the same as the Go function. The limitations on
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# the argument list are the same as for the //sys line, but there must
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# be at most one result parameter, and it must be given as just a
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# type, without a name.
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BEGIN {
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print "// This file was automatically generated by mksyscall.awk"
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print ""
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print "package syscall"
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print ""
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print "import \"unsafe\""
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print ""
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status = 0
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}
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/^\/\/sys/ {
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if ($1 == "//sysnb") {
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blocking = 0
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} else {
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blocking = 1
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}
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line = $0
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if (match(line, "//sys(nb)?[ ]*[a-zA-Z0-9_]+\\([^()]*\\) *(\\(([^()]+)\\))?") == 0) {
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print "unmatched line:", $0 | "cat 1>&2"
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status = 1
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next
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}
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# Sets a[1] = //sysnb, a[2] == function name.
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split(line, a, "[ (]*")
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gofnname = a[2]
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off = match(line, "\\([^()]*\\)")
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end = index(substr(line, off, length(line) - off + 1), ")")
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gofnparams = substr(line, off + 1, end - 2)
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line = substr(line, off + end, length(line) - (off + end) + 1)
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off = match(line, "\\([^()]*\\)")
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if (off == 0) {
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gofnresults = ""
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} else {
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end = index(substr(line, off, length(line) - off + 1), ")")
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gofnresults = substr(line, off + 1, end - 2)
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}
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getline
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line = $0
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if (match(line, "//[a-zA-Z0-9_]+\\([^()]*\\)") == 0) {
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print "unmatched C line", $0, "after", gofnname | "cat 1>&2"
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status = 1
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next
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}
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split(line, a, "[ (]*")
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cfnname = substr(a[1], 3, length(a[1]) - 2)
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off = match(line, "\\([^()]*\\)")
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end = index(substr(line, off, length(line) - off + 1), ")")
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cfnparams = substr(line, off + 1, end - 2)
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line = substr(line, off + end + 1, length(line) - (off + end) + 1)
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while (substr(line, 1, 1) == " ") {
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line = substr(line, 2, length(line) - 1)
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}
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end = index(line, " ")
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if (end != 0) {
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line = substr(line, 1, end)
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}
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cfnresult = line
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printf("// Automatically generated wrapper for %s/%s\n", gofnname, cfnname)
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printf("//extern %s\n", cfnname)
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printf("func c_%s(%s) %s\n", cfnname, cfnparams, cfnresult)
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printf("func %s(%s) %s%s%s%s{\n",
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gofnname, gofnparams, gofnresults == "" ? "" : "(", gofnresults,
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gofnresults == "" ? "" : ")", gofnresults == "" ? "" : " ")
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loc = gofnname "/" cfnname ":"
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haserr = 0
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if (gofnresults != "") {
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fields = split(gofnresults, goresults, ", *")
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for (goresult = 1; goresults[goresult] != ""; goresult++) {
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if (split(goresults[goresult], goparam) == 2) {
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if (goparam[1] == "err") {
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haserr = 1
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break
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}
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}
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}
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}
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split(gofnparams, goargs, ", *")
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split(cfnparams, cargs, ", *")
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args = ""
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carg = 1
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for (goarg = 1; goargs[goarg] != ""; goarg++) {
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if (cargs[carg] == "") {
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print loc, "not enough C parameters"
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}
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if (args != "") {
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args = args ", "
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}
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if (split(goargs[goarg], a) != 2) {
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print loc, "bad parameter:", goargs[goarg] | "cat 1>&2"
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status = 1
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next
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}
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goname = a[1]
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gotype = a[2]
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if (split(cargs[carg], a) != 2) {
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print loc, "bad C parameter:", cargs[carg] | "cat 1>&2"
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status = 1
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next
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}
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ctype = a[2]
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if (gotype ~ /^\*/) {
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if (gotype != ctype) {
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print loc, "Go/C pointer type mismatch:", gotype, ctype | "cat 1>&2"
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status = 1
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next
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}
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args = args goname
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} else if (gotype == "string") {
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if (ctype != "*byte") {
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print loc, "Go string not matched to C *byte:", gotype, ctype | "cat 1>&2"
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status = 1
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next
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}
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printf("\tvar _p%d *byte\n", goarg)
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if (haserr) {
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printf("\t_p%d, err = BytePtrFromString(%s)\n", goarg, goname)
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printf("\tif err != nil {\n\t\treturn\n\t}\n")
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} else {
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print loc, "uses string arguments but has no error return" | "cat 1>&2"
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printf("\t_p%d, _ = BytePtrFromString(%s)\n", goarg, goname)
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}
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args = sprintf("%s_p%d", args, goarg)
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} else if (gotype ~ /^\[\](.*)/) {
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if (ctype !~ /^\*/ || cargs[carg + 1] == "") {
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print loc, "bad C type for slice:", gotype, ctype | "cat 1>&2"
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status = 1
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next
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}
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# Convert a slice into a pair of pointer, length.
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# Don't try to take the address of the zeroth element of a
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# nil slice.
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printf("\tvar _p%d %s\n", goarg, ctype)
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printf("\tif len(%s) > 0 {\n", goname)
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printf("\t\t_p%d = (%s)(unsafe.Pointer(&%s[0]))\n", goarg, ctype, goname)
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printf("\t} else {\n")
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printf("\t\t_p%d = (%s)(unsafe.Pointer(&_zero))\n", goarg, ctype)
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printf("\t}\n")
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++carg
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if (split(cargs[carg], cparam) != 2) {
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print loc, "bad C parameter:", cargs[carg] | "cat 1>&2"
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status = 1
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next
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}
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args = sprintf("%s_p%d, %s(len(%s))", args, goarg, cparam[2], goname)
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} else if (gotype == "uintptr" && ctype ~ /^\*/) {
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args = sprintf("%s(%s)(unsafe.Pointer(%s))", args, ctype, goname)
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} else {
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args = sprintf("%s%s(%s)", args, ctype, goname)
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}
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carg++
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}
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if (cargs[carg] != "") {
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print loc, "too many C parameters" | "cat 1>&2"
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status = 1
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next
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}
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if (blocking) {
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print "\tEntersyscall()"
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}
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printf("\t")
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if (gofnresults != "") {
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printf("_r := ")
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}
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printf("c_%s(%s)\n", cfnname, args)
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seterr = 0
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if (gofnresults != "") {
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fields = split(gofnresults, goresults, ", *")
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if (fields > 2) {
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print loc, "too many Go results" | "cat 1>&2"
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status = 1
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next
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}
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usedr = 0
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for (goresult = 1; goresults[goresult] != ""; goresult++) {
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if (split(goresults[goresult], goparam) != 2) {
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print loc, "bad result:", goresults[goresult] | "cat 1>&2"
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status = 1
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next
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}
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goname = goparam[1]
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gotype = goparam[2]
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if (goname == "err") {
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print "\tvar errno Errno"
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print "\tsetErrno := false"
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if (cfnresult ~ /^\*/) {
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print "\tif _r == nil {"
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} else {
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print "\tif _r < 0 {"
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}
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print "\t\terrno = GetErrno()"
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print "\t\tsetErrno = true"
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print "\t}"
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seterr = 1
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} else if (gotype == "uintptr" && cfnresult ~ /^\*/) {
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printf("\t%s = (%s)(unsafe.Pointer(_r))\n", goname, gotype)
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} else {
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if (usedr) {
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print loc, "two parameters but no errno parameter" | "cat 1>&2"
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status = 1
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next
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}
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printf("\t%s = (%s)(_r)\n", goname, gotype)
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usedr = 1
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}
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}
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}
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if (blocking) {
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print "\tExitsyscall()"
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}
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if (seterr) {
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print "\tif setErrno {"
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print "\t\terr = errno"
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print "\t}"
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}
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if (gofnresults != "") {
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print "\treturn"
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}
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print "}"
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print ""
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next
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}
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{ next }
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END {
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if (status != 0) {
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print "*** mksyscall.awk failed" | "cat 1>&2"
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exit status
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}
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}
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