Bug 772734 - Fixes LaunchApp hang when launching. r=cjones

From c6bdfcf39e3dfe28fe7376f8c0b1b9d07a1d969b Mon Sep 17 00:00:00 2001
 plugin-container - v4
Added checks in case PR_DuplicateEnvironment or PR_Malloc fail
Added #ifdef so that only Android builds try to call PR_DuplicateEnvironment
---
 ipc/chromium/src/base/process_util_linux.cc |  121 +++++++++++++++++++++++++--
 1 file changed, 115 insertions(+), 6 deletions(-)

ipc/chromium/src/base/process_util_linux.cc

@@ -7,6 +7,7 @@
 #include <ctype.h>
 #include <dirent.h>
 #include <fcntl.h>
+#include <memory>
 #include <unistd.h>
 #include <string>
 #include <sys/types.h>
@@ -19,6 +20,19 @@
 #include "base/string_tokenizer.h"
 #include "base/string_util.h"
 
+#ifdef ANDROID
+/*
+ * Currently, PR_DuplicateEnvironment is implemented in mozglue/build/BionicGlue.cpp
+ */
+#define HAVE_PR_DUPLICATE_ENVIRONMENT
+
+#include "plstr.h"
+#include "prenv.h"
+#include "prmem.h"
+/* Temporary until we have PR_DuplicateEnvironment in prenv.h */
+extern "C" { NSPR_API(char **)PR_DuplicateEnvironment(void); }
+#endif
+
 namespace {
 
 enum ParsingState {
@@ -32,6 +46,87 @@ static mozilla::EnvironmentLog gProcessLog("MOZ_PROCESS_LOG");
 
 namespace base {
 
+#ifdef HAVE_PR_DUPLICATE_ENVIRONMENT
+class EnvironmentEnvp
+{
+public:
+  EnvironmentEnvp()
+    : mEnvp(PR_DuplicateEnvironment()) {}
+
+  EnvironmentEnvp(const environment_map &em)
+  {
+    mEnvp = (char **)PR_Malloc(sizeof(char *) * (em.size() + 1));
+    if (!mEnvp) {
+      return;
+    }
+    char **e = mEnvp;
+    for (environment_map::const_iterator it = em.begin();
+         it != em.end(); ++it, ++e) {
+      std::string str = it->first;
+      str += "=";
+      str += it->second;
+      *e = PL_strdup(str.c_str());
+    }
+    *e = NULL;
+  }
+
+  ~EnvironmentEnvp()
+  {
+    if (!mEnvp) {
+      return;
+    }
+    for (char **e = mEnvp; *e; ++e) {
+      PL_strfree(*e);
+    }
+    PR_Free(mEnvp);
+  }
+
+  char * const *AsEnvp() { return mEnvp; }
+
+  void ToMap(environment_map &em)
+  {
+    if (!mEnvp) {
+      return;
+    }
+    em.clear();
+    for (char **e = mEnvp; *e; ++e) {
+      const char *eq;
+      if ((eq = strchr(*e, '=')) != NULL) {
+        std::string varname(*e, eq - *e);
+        em[varname.c_str()] = &eq[1];
+      }
+    }
+  }
+
+private:
+  char **mEnvp;
+};
+
+class Environment : public environment_map
+{
+public:
+  Environment()
+  {
+    EnvironmentEnvp envp;
+    envp.ToMap(*this);
+  }
+
+  char * const *AsEnvp() {
+    mEnvp.reset(new EnvironmentEnvp(*this));
+    return mEnvp->AsEnvp();
+  }
+
+  void Merge(const environment_map &em)
+  {
+    for (const_iterator it = em.begin(); it != em.end(); ++it) {
+      (*this)[it->first] = it->second;
+    }
+  }
+private:
+  std::auto_ptr<EnvironmentEnvp> mEnvp;
+};
+#endif // HAVE_PR_DUPLICATE_ENVIRONMENT
+
 bool LaunchApp(const std::vector<std::string>& argv,
                const file_handle_mapping_vector& fds_to_remap,
                bool wait, ProcessHandle* process_handle) {
@@ -50,6 +145,16 @@ bool LaunchApp(const std::vector<std::string>& argv,
   fd_shuffle1.reserve(fds_to_remap.size());
   fd_shuffle2.reserve(fds_to_remap.size());
 
+#ifdef HAVE_PR_DUPLICATE_ENVIRONMENT
+  Environment env;
+  env.Merge(env_vars_to_set);
+  char * const *envp = env.AsEnvp();
+  if (!envp) {
+    DLOG(ERROR) << "FAILED to duplicate environment for: " << argv_cstr[0];
+    return false;
+  }
+#endif
+
   pid_t pid = fork();
   if (pid < 0)
     return false;
@@ -66,19 +171,23 @@ bool LaunchApp(const std::vector<std::string>& argv,
 
     CloseSuperfluousFds(fd_shuffle2);
 
+    for (size_t i = 0; i < argv.size(); i++)
+      argv_cstr[i] = const_cast<char*>(argv[i].c_str());
+    argv_cstr[argv.size()] = NULL;
+
+#ifdef HAVE_PR_DUPLICATE_ENVIRONMENT
+    execve(argv_cstr[0], argv_cstr.get(), envp);
+#else
     for (environment_map::const_iterator it = env_vars_to_set.begin();
          it != env_vars_to_set.end(); ++it) {
       if (setenv(it->first.c_str(), it->second.c_str(), 1/*overwrite*/))
         _exit(127);
     }
-
-    for (size_t i = 0; i < argv.size(); i++)
-      argv_cstr[i] = const_cast<char*>(argv[i].c_str());
-    argv_cstr[argv.size()] = NULL;
-    execvp(argv_cstr[0], argv_cstr.get());
+    execv(argv_cstr[0], argv_cstr.get());
+#endif
     // if we get here, we're in serious trouble and should complain loudly
     DLOG(ERROR) << "FAILED TO exec() CHILD PROCESS, path: " << argv_cstr[0];
-    exit(127);
+    _exit(127);
   } else {
     gProcessLog.print("==> process %d launched child process %d\n",
                       GetCurrentProcId(), pid);