forkserver: set process titles for processes

this is unfortunately truncated on Linux, but I don't care enough to
hack around this

2 files changed, 42 insertions, 0 deletions

diff --git a/src/server/forkserver.nim b/src/server/forkserver.nim
index 12b25dc3..5a123fcd 100644
--- a/src/server/forkserver.nim
+++ b/src/server/forkserver.nim
@@ -14,6 +14,7 @@ import server/buffer
 import types/urimethodmap
 import types/url
 import types/winattrs
+import utils/proctitle
 import utils/strwidth
 
 import chagashi/charset
@@ -86,6 +87,7 @@ proc forkLoader(ctx: var ForkServerContext, config: LoaderConfig): int =
     zeroMem(addr ctx, sizeof(ctx))
     discard close(pipefd[0]) # close read
     try:
+      setProcessTitle("cha loader")
       runFileLoader(pipefd[1], config)
     except CatchableError:
       let e = getCurrentException()
@@ -152,6 +154,7 @@ proc forkBuffer(ctx: var ForkServerContext): int =
       clientPid: pid
     )
     try:
+      setBufferProcessTitle(url)
       launchBuffer(config, url, request, attrs, ishtml, charsetStack, loader,
         ssock)
     except CatchableError:
@@ -171,6 +174,7 @@ proc forkBuffer(ctx: var ForkServerContext): int =
   return pid
 
 proc runForkServer() =
+  setProcessTitle("cha forkserver")
   var ctx = ForkServerContext(
     istream: newPosixStream(stdin.getFileHandle()),
     ostream: newPosixStream(stdout.getFileHandle())
diff --git a/src/utils/proctitle.nim b/src/utils/proctitle.nim
new file mode 100644
index 00000000..4694be0b
--- /dev/null
+++ b/src/utils/proctitle.nim
@@ -0,0 +1,38 @@
+import types/url
+
+when defined(freebsd):
+  proc c_setproctitle(fmt: cstring) {.header: "<unistd.h>", importc:
+    "setproctitle", varargs.}
+elif defined(netbsd) or defined(openbsd):
+  proc c_setproctitle(fmt: cstring) {.header: "<stdlib.h>", importc:
+    "setproctitle", varargs.}
+elif defined(linux):
+  let PR_SET_NAME {.importc, header: "<sys/prctl.h>", nodecl.}: cint
+  proc prctl(option: cint; arg2, arg3, arg4, arg5: culong): cint {.importc,
+    header: "<sys/prctl.h>".}
+
+proc setProcessTitle*(s: string) =
+  when defined(freebsd) or defined(netbsd) or defined(openbsd):
+    c_setproctitle("%s", cstring(s))
+  elif defined(linux):
+    discard prctl(PR_SET_NAME, cast[culong](cstring(s)), 0, 0, 0)
+
+when defined(linux):
+  from std/strutils import startsWith, delete
+  from utils/twtstr import afterLast
+
+proc setBufferProcessTitle*(url: URL) =
+  when defined(linux):
+    # linux truncates to 15 chars; try to preserve important info
+    const initTitle = "cha buf "
+    var title = initTitle
+    var hostname = url.hostname
+    if hostname.startsWith("www."):
+      hostname.delete(0.."www.".high)
+    title &= hostname
+    if title.len > initTitle.len:
+      title &= ' '
+    title &= url.pathname.afterLast('/')
+    setProcessTitle(title)
+  else:
+    setProcessTitle("cha buffer " & $url)