commit 8f38048f7d23686a6f008e24cefb45972299d309
author Tom Cherry <tomcherry@google.com> Tue Apr 17 14:48:44 2018 -0700
committer Tom Cherry <tomcherry@google.com> Tue Apr 17 14:52:49 2018 -0700
tree 42223b38bcda5296332d00d525b8cc70d8c671c9
parent 22dc27b9fa46b20aca4f5982979681a858a97284

init: add sigstop option for debugging services from their start

Test: the examples in README.md
Change-Id: Idb528ea4017f8f4ce62911928c040f4bc558d196

init/service.cpp

diff --git a/init/service.cpp b/init/service.cpp
index 694e5e7..0227161 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -155,7 +155,7 @@
     }
 }
 
-static bool ExpandArgsAndExecv(const std::vector<std::string>& args) {
+static bool ExpandArgsAndExecv(const std::vector<std::string>& args, bool sigstop) {
     std::vector<std::string> expanded_args;
     std::vector<char*> c_strings;
 
@@ -169,6 +169,10 @@
     }
     c_strings.push_back(nullptr);
 
+    if (sigstop) {
+        kill(getpid(), SIGSTOP);
+    }
+
     return execv(c_strings[0], c_strings.data()) == 0;
 }
 
@@ -578,6 +582,11 @@
     return Success();
 }
 
+Result<Success> Service::ParseSigstop(const std::vector<std::string>& args) {
+    sigstop_ = true;
+    return Success();
+}
+
 Result<Success> Service::ParseSetenv(const std::vector<std::string>& args) {
     environment_vars_.emplace_back(args[1], args[2]);
     return Success();
@@ -700,6 +709,7 @@
         {"seclabel",    {1,     1,    &Service::ParseSeclabel}},
         {"setenv",      {2,     2,    &Service::ParseSetenv}},
         {"shutdown",    {1,     1,    &Service::ParseShutdown}},
+        {"sigstop",     {0,     0,    &Service::ParseSigstop}},
         {"socket",      {3,     6,    &Service::ParseSocket}},
         {"user",        {1,     1,    &Service::ParseUser}},
         {"writepid",    {1,     kMax, &Service::ParseWritepid}},
@@ -858,7 +868,7 @@
         // priority. Aborts on failure.
         SetProcessAttributes();
 
-        if (!ExpandArgsAndExecv(args_)) {
+        if (!ExpandArgsAndExecv(args_, sigstop_)) {
             PLOG(ERROR) << "cannot execve('" << args_[0] << "')";
         }