Add generate-syscall-docs command.

Adds a new command to automatically generate the syscall compatibility
docs from runsc.

1 files changed, 203 insertions, 0 deletions

diff --git a/cmd/generate-syscall-docs/main.go b/cmd/generate-syscall-docs/main.go
new file mode 100644
index 000000000..006bd1ce5
--- /dev/null
+++ b/cmd/generate-syscall-docs/main.go
@@ -0,0 +1,203 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"bufio"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"text/template"
+)
+
+type CompatibilityInfo map[string]map[string]ArchInfo
+
+// ArchInfo is compatbility doc for an architecture.
+type ArchInfo struct {
+	// Syscalls maps syscall number for the architecture to the doc.
+	Syscalls map[uintptr]SyscallDoc `json:"syscalls"`
+}
+
+// SyscallDoc represents a single item of syscall documentation.
+type SyscallDoc struct {
+	Name    string   `json:"name"`
+	Support string   `json:"support"`
+	Note    string   `json:"note,omitempty"`
+	URLs    []string `json:"urls,omitempty"`
+}
+
+var mdTemplate = template.Must(template.New("out").Parse(`
++++
+title = "{{.OS}}/{{.Arch}}"
+description = "Syscall Compatibility Reference Documentation for {{.OS}}/{{.Arch}}"
+weight = {{.Weight}}
++++
+
+This table is a reference of {{.OS}} syscalls for the {{.Arch}} architecture and
+their compatibility status in gVisor. gVisor does not support all syscalls and
+some syscalls may have a partial implementation.
+
+Of {{.Total}} syscalls, {{.Supported}} syscalls have a full or partial
+implementation. There are currently {{.Unsupported}} unsupported
+syscalls. {{if .Undocumented}}{{.Undocumented}} syscalls are not yet documented.{{end}}
+
+<table>
+  <thead>
+    <tr>
+      <th>#</th>
+      <th>Name</th>
+      <th>Support</th>
+      <th>Notes</th>
+    </tr>
+  </thead>
+  <tbody>
+ 	{{range $i, $syscall := .Syscalls}}
+    <tr>
+      <td><a class="doc-table-anchor" id="{{.Name}}"></a>{{.Number}}</td>
+      <td><a href="http://man7.org/linux/man-pages/man2/{{.Name}}.2.html" target="_blank" rel="noopener">{{.Name}}</a></td>
+      <td>{{.Support}}</td>
+	  <td>{{.Note}} {{range $i, $url := .URLs}}<br/>See: <a href="{{.}}">{{.}}</a>{{end}}</td>
+    </tr>
+	{{end}}
+  </tbody>
+</table>
+`))
+
+// Fatalf writes a message to stderr and exits with error code 1
+func Fatalf(format string, a ...interface{}) {
+	fmt.Fprintf(os.Stderr, format, a...)
+	os.Exit(1)
+}
+
+func main() {
+	inputFlag := flag.String("in", "-", "File to input ('-' for stdin)")
+	outputDir := flag.String("out", ".", "Directory to output files.")
+
+	flag.Parse()
+
+	var input io.Reader
+	if *inputFlag == "-" {
+		input = os.Stdin
+	} else {
+		i, err := os.Open(*inputFlag)
+		if err != nil {
+			Fatalf("Error opening %q: %v", *inputFlag, err)
+		}
+		input = i
+	}
+	input = bufio.NewReader(input)
+
+	var info CompatibilityInfo
+	d := json.NewDecoder(input)
+	if err := d.Decode(&info); err != nil {
+		Fatalf("Error reading json: %v")
+	}
+
+	weight := 0
+	for osName, osInfo := range info {
+		for archName, archInfo := range osInfo {
+			outDir := filepath.Join(*outputDir, osName)
+			outFile := filepath.Join(outDir, archName+".md")
+
+			if err := os.MkdirAll(outDir, 0755); err != nil {
+				Fatalf("Error creating directory %q: %v", *outputDir, err)
+			}
+
+			f, err := os.OpenFile(outFile, os.O_RDWR|os.O_CREATE, 0644)
+			if err != nil {
+				Fatalf("Error opening file %q: %v", outFile, err)
+			}
+			defer f.Close()
+
+			weight += 10
+			data := struct {
+				OS           string
+				Arch         string
+				Weight       int
+				Total        int
+				Supported    int
+				Unsupported  int
+				Undocumented int
+				Syscalls     []struct {
+					Name    string
+					Number  uintptr
+					Support string
+					Note    string
+					URLs    []string
+				}
+			}{
+				OS:           strings.Title(osName),
+				Arch:         archName,
+				Weight:       weight,
+				Total:        0,
+				Supported:    0,
+				Unsupported:  0,
+				Undocumented: 0,
+				Syscalls: []struct {
+					Name    string
+					Number  uintptr
+					Support string
+					Note    string
+					URLs    []string
+				}{},
+			}
+
+			for num, s := range archInfo.Syscalls {
+				switch s.Support {
+				case "Full Support", "Partial Support":
+					data.Supported++
+				case "Unimplemented":
+					data.Unsupported++
+				default:
+					data.Undocumented++
+				}
+				data.Total++
+
+				for i := range s.URLs {
+					if !strings.HasPrefix(s.URLs[i], "http://") && !strings.HasPrefix(s.URLs[i], "https://") {
+						s.URLs[i] = "https://" + s.URLs[i]
+					}
+				}
+
+				data.Syscalls = append(data.Syscalls, struct {
+					Name    string
+					Number  uintptr
+					Support string
+					Note    string
+					URLs    []string
+				}{
+					Name:    s.Name,
+					Number:  num,
+					Support: s.Support,
+					Note:    s.Note, // TODO urls
+					URLs:    s.URLs,
+				})
+			}
+
+			sort.Slice(data.Syscalls, func(i, j int) bool {
+				return data.Syscalls[i].Number < data.Syscalls[j].Number
+			})
+
+			if err := mdTemplate.Execute(f, data); err != nil {
+				Fatalf("Error writing file %q: %v", outFile, err)
+			}
+		}
+	}
+}