git.iko.soy/crush
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crush/internal/agent/tools/bash.go
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1package tools
3import (
4 "bytes"
5 "cmp"
6 "context"
7 _ "embed"
8 "fmt"
9 "html/template"
10 "os"
11 "path/filepath"
12 "runtime"
13 "strings"
14 "time"
16 "charm.land/fantasy"
17 "github.com/charmbracelet/crush/internal/config"
18 "github.com/charmbracelet/crush/internal/permission"
19 "github.com/charmbracelet/crush/internal/shell"
22type BashParams struct {
23 Description string `json:"description" description:"A brief description of what the command does, try to keep it under 30 characters or so"`
24 Command string `json:"command" description:"The command to execute"`
25 WorkingDir string `json:"working_dir,omitempty" description:"The working directory to execute the command in (defaults to current directory)"`
26 RunInBackground bool `json:"run_in_background,omitempty" description:"Set to true (boolean) to run this command in the background. Use job_output to read the output later."`
29type BashPermissionsParams struct {
30 Description string `json:"description"`
31 Command string `json:"command"`
32 WorkingDir string `json:"working_dir"`
33 RunInBackground bool `json:"run_in_background"`
36type BashResponseMetadata struct {
37 StartTime int64 `json:"start_time"`
38 EndTime int64 `json:"end_time"`
39 Output string `json:"output"`
40 Description string `json:"description"`
41 WorkingDirectory string `json:"working_directory"`
42 Background bool `json:"background,omitempty"`
43 ShellID string `json:"shell_id,omitempty"`
46const (
47 BashToolName = "bash"
49 AutoBackgroundThreshold = 1 * time.Minute // Commands taking longer automatically become background jobs
50 MaxOutputLength = 30000
51 BashNoOutput = "no output"
54//go:embed bash.tpl
55var bashDescriptionTmpl []byte
57var bashDescriptionTpl = template.Must(
58 template.New("bashDescription").
59 Parse(string(bashDescriptionTmpl)),
62type bashDescriptionData struct {
63 BannedCommands string
64 MaxOutputLength int
65 Attribution config.Attribution
66 ModelName string
69var bannedCommands = []string{
70 // Network/Download tools
71 "alias",
72 "aria2c",
73 "axel",
74 "chrome",
75 "curl",
76 "curlie",
77 "firefox",
78 "http-prompt",
79 "httpie",
80 "links",
81 "lynx",
82 "nc",
83 "safari",
84 "scp",
85 "ssh",
86 "telnet",
87 "w3m",
88 "wget",
89 "xh",
91 // System administration
92 "doas",
93 "su",
94 "sudo",
96 // Package managers
97 "apk",
98 "apt",
99 "apt-cache",
100 "apt-get",
101 "dnf",
102 "dpkg",
103 "emerge",
104 "home-manager",
105 "makepkg",
106 "opkg",
107 "pacman",
108 "paru",
109 "pkg",
110 "pkg_add",
111 "pkg_delete",
112 "portage",
113 "rpm",
114 "yay",
115 "yum",
116 "zypper",
118 // System modification
119 "at",
120 "batch",
121 "chkconfig",
122 "crontab",
123 "fdisk",
124 "mkfs",
125 "mount",
126 "parted",
127 "service",
128 "systemctl",
129 "umount",
131 // Network configuration
132 "firewall-cmd",
133 "ifconfig",
134 "ip",
135 "iptables",
136 "netstat",
137 "pfctl",
138 "route",
139 "ufw",
142func bashDescription(attribution *config.Attribution, modelName string) string {
143 bannedCommandsStr := strings.Join(bannedCommands, ", ")
144 var out bytes.Buffer
145 if err := bashDescriptionTpl.Execute(&out, bashDescriptionData{
146 BannedCommands: bannedCommandsStr,
147 MaxOutputLength: MaxOutputLength,
148 Attribution: *attribution,
149 ModelName: modelName,
150 }); err != nil {
151 // this should never happen.
152 panic("failed to execute bash description template: " + err.Error())
153 }
154 return out.String()
157func blockFuncs() []shell.BlockFunc {
158 return []shell.BlockFunc{
159 shell.CommandsBlocker(bannedCommands),
161 // System package managers
162 shell.ArgumentsBlocker("apk", []string{"add"}, nil),
163 shell.ArgumentsBlocker("apt", []string{"install"}, nil),
164 shell.ArgumentsBlocker("apt-get", []string{"install"}, nil),
165 shell.ArgumentsBlocker("dnf", []string{"install"}, nil),
166 shell.ArgumentsBlocker("pacman", nil, []string{"-S"}),
167 shell.ArgumentsBlocker("pkg", []string{"install"}, nil),
168 shell.ArgumentsBlocker("yum", []string{"install"}, nil),
169 shell.ArgumentsBlocker("zypper", []string{"install"}, nil),
171 // Language-specific package managers
172 shell.ArgumentsBlocker("brew", []string{"install"}, nil),
173 shell.ArgumentsBlocker("cargo", []string{"install"}, nil),
174 shell.ArgumentsBlocker("gem", []string{"install"}, nil),
175 shell.ArgumentsBlocker("go", []string{"install"}, nil),
176 shell.ArgumentsBlocker("npm", []string{"install"}, []string{"--global"}),
177 shell.ArgumentsBlocker("npm", []string{"install"}, []string{"-g"}),
178 shell.ArgumentsBlocker("pip", []string{"install"}, []string{"--user"}),
179 shell.ArgumentsBlocker("pip3", []string{"install"}, []string{"--user"}),
180 shell.ArgumentsBlocker("pnpm", []string{"add"}, []string{"--global"}),
181 shell.ArgumentsBlocker("pnpm", []string{"add"}, []string{"-g"}),
182 shell.ArgumentsBlocker("yarn", []string{"global", "add"}, nil),
184 // `go test -exec` can run arbitrary commands
185 shell.ArgumentsBlocker("go", []string{"test"}, []string{"-exec"}),
186 }
189func NewBashTool(permissions permission.Service, workingDir string, attribution *config.Attribution, modelName string) fantasy.AgentTool {
190 return fantasy.NewAgentTool(
191 BashToolName,
192 string(bashDescription(attribution, modelName)),
193 func(ctx context.Context, params BashParams, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
194 if params.Command == "" {
195 return fantasy.NewTextErrorResponse("missing command"), nil
196 }
198 // Determine working directory
199 execWorkingDir := cmp.Or(params.WorkingDir, workingDir)
201 isSafeReadOnly := false
202 cmdLower := strings.ToLower(params.Command)
204 for _, safe := range safeCommands {
205 if strings.HasPrefix(cmdLower, safe) {
206 if len(cmdLower) == len(safe) || cmdLower[len(safe)] == ' ' || cmdLower[len(safe)] == '-' {
207 isSafeReadOnly = true
208 break
209 }
210 }
211 }
213 sessionID := GetSessionFromContext(ctx)
214 if sessionID == "" {
215 return fantasy.ToolResponse{}, fmt.Errorf("session ID is required for executing shell command")
216 }
217 if !isSafeReadOnly {
218 p := permissions.Request(
219 permission.CreatePermissionRequest{
220 SessionID: sessionID,
221 Path: execWorkingDir,
222 ToolCallID: call.ID,
223 ToolName: BashToolName,
224 Action: "execute",
225 Description: fmt.Sprintf("Execute command: %s", params.Command),
226 Params: BashPermissionsParams(params),
227 },
228 )
229 if !p {
230 return fantasy.ToolResponse{}, permission.ErrorPermissionDenied
231 }
232 }
234 // If explicitly requested as background, start immediately with detached context
235 if params.RunInBackground {
236 startTime := time.Now()
237 bgManager := shell.GetBackgroundShellManager()
238 bgManager.Cleanup()
239 // Use background context so it continues after tool returns
240 bgShell, err := bgManager.Start(context.Background(), execWorkingDir, blockFuncs(), params.Command, params.Description)
241 if err != nil {
242 return fantasy.ToolResponse{}, fmt.Errorf("error starting background shell: %w", err)
243 }
245 // Wait a short time to detect fast failures (blocked commands, syntax errors, etc.)
246 time.Sleep(1 * time.Second)
247 stdout, stderr, done, execErr := bgShell.GetOutput()
249 if done {
250 // Command failed or completed very quickly
251 bgManager.Remove(bgShell.ID)
253 interrupted := shell.IsInterrupt(execErr)
254 exitCode := shell.ExitCode(execErr)
255 if exitCode == 0 && !interrupted && execErr != nil {
256 return fantasy.ToolResponse{}, fmt.Errorf("[Job %s] error executing command: %w", bgShell.ID, execErr)
257 }
259 stdout = formatOutput(stdout, stderr, execErr)
261 metadata := BashResponseMetadata{
262 StartTime: startTime.UnixMilli(),
263 EndTime: time.Now().UnixMilli(),
264 Output: stdout,
265 Description: params.Description,
266 Background: params.RunInBackground,
267 WorkingDirectory: bgShell.WorkingDir,
268 }
269 if stdout == "" {
270 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(BashNoOutput), metadata), nil
271 }
272 stdout += fmt.Sprintf("\n\n<cwd>%s</cwd>", normalizeWorkingDir(bgShell.WorkingDir))
273 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(stdout), metadata), nil
274 }
276 // Still running after fast-failure check - return as background job
277 metadata := BashResponseMetadata{
278 StartTime: startTime.UnixMilli(),
279 EndTime: time.Now().UnixMilli(),
280 Description: params.Description,
281 WorkingDirectory: bgShell.WorkingDir,
282 Background: true,
283 ShellID: bgShell.ID,
284 }
285 response := fmt.Sprintf("Background shell started with ID: %s\n\nUse job_output tool to view output or job_kill to terminate.", bgShell.ID)
286 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(response), metadata), nil
287 }
289 // Start synchronous execution with auto-background support
290 startTime := time.Now()
292 // Start with detached context so it can survive if moved to background
293 bgManager := shell.GetBackgroundShellManager()
294 bgManager.Cleanup()
295 bgShell, err := bgManager.Start(context.Background(), execWorkingDir, blockFuncs(), params.Command, params.Description)
296 if err != nil {
297 return fantasy.ToolResponse{}, fmt.Errorf("error starting shell: %w", err)
298 }
300 // Wait for either completion, auto-background threshold, or context cancellation
301 ticker := time.NewTicker(100 * time.Millisecond)
302 defer ticker.Stop()
303 timeout := time.After(AutoBackgroundThreshold)
305 var stdout, stderr string
306 var done bool
307 var execErr error
309 waitLoop:
310 for {
311 select {
312 case <-ticker.C:
313 stdout, stderr, done, execErr = bgShell.GetOutput()
314 if done {
315 break waitLoop
316 }
317 case <-timeout:
318 stdout, stderr, done, execErr = bgShell.GetOutput()
319 break waitLoop
320 case <-ctx.Done():
321 // Incoming context was cancelled before we moved to background
322 // Kill the shell and return error
323 bgManager.Kill(bgShell.ID)
324 return fantasy.ToolResponse{}, ctx.Err()
325 }
326 }
328 if done {
329 // Command completed within threshold - return synchronously
330 // Remove from background manager since we're returning directly
331 // Don't call Kill() as it cancels the context and corrupts the exit code
332 bgManager.Remove(bgShell.ID)
334 interrupted := shell.IsInterrupt(execErr)
335 exitCode := shell.ExitCode(execErr)
336 if exitCode == 0 && !interrupted && execErr != nil {
337 return fantasy.ToolResponse{}, fmt.Errorf("[Job %s] error executing command: %w", bgShell.ID, execErr)
338 }
340 stdout = formatOutput(stdout, stderr, execErr)
342 metadata := BashResponseMetadata{
343 StartTime: startTime.UnixMilli(),
344 EndTime: time.Now().UnixMilli(),
345 Output: stdout,
346 Description: params.Description,
347 Background: params.RunInBackground,
348 WorkingDirectory: bgShell.WorkingDir,
349 }
350 if stdout == "" {
351 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(BashNoOutput), metadata), nil
352 }
353 stdout += fmt.Sprintf("\n\n<cwd>%s</cwd>", normalizeWorkingDir(bgShell.WorkingDir))
354 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(stdout), metadata), nil
355 }
357 // Still running - keep as background job
358 metadata := BashResponseMetadata{
359 StartTime: startTime.UnixMilli(),
360 EndTime: time.Now().UnixMilli(),
361 Description: params.Description,
362 WorkingDirectory: bgShell.WorkingDir,
363 Background: true,
364 ShellID: bgShell.ID,
365 }
366 response := fmt.Sprintf("Command is taking longer than expected and has been moved to background.\n\nBackground shell ID: %s\n\nUse job_output tool to view output or job_kill to terminate.", bgShell.ID)
367 return fantasy.WithResponseMetadata(fantasy.NewTextResponse(response), metadata), nil
368 })
371// formatOutput formats the output of a completed command with error handling
372func formatOutput(stdout, stderr string, execErr error) string {
373 interrupted := shell.IsInterrupt(execErr)
374 exitCode := shell.ExitCode(execErr)
376 stdout = truncateOutput(stdout)
377 stderr = truncateOutput(stderr)
379 errorMessage := stderr
380 if errorMessage == "" && execErr != nil {
381 errorMessage = execErr.Error()
382 }
384 if interrupted {
385 if errorMessage != "" {
386 errorMessage += "\n"
387 }
388 errorMessage += "Command was aborted before completion"
389 } else if exitCode != 0 {
390 if errorMessage != "" {
391 errorMessage += "\n"
392 }
393 errorMessage += fmt.Sprintf("Exit code %d", exitCode)
394 }
396 hasBothOutputs := stdout != "" && stderr != ""
398 if hasBothOutputs {
399 stdout += "\n"
400 }
402 if errorMessage != "" {
403 stdout += "\n" + errorMessage
404 }
406 return stdout
409func truncateOutput(content string) string {
410 if len(content) <= MaxOutputLength {
411 return content
412 }
414 halfLength := MaxOutputLength / 2
415 start := content[:halfLength]
416 end := content[len(content)-halfLength:]
418 truncatedLinesCount := countLines(content[halfLength : len(content)-halfLength])
419 return fmt.Sprintf("%s\n\n... [%d lines truncated] ...\n\n%s", start, truncatedLinesCount, end)
422func countLines(s string) int {
423 if s == "" {
424 return 0
425 }
426 return len(strings.Split(s, "\n"))
429func normalizeWorkingDir(path string) string {
430 if runtime.GOOS == "windows" {
431 cwd, err := os.Getwd()
432 if err != nil {
433 cwd = "C:"
434 }
435 path = strings.ReplaceAll(path, filepath.VolumeName(cwd), "")
436 }
438 return filepath.ToSlash(path)