added run_shell; temporarily suspend signals during fork

Author: kroening

src/util/run.cpp

@@ -23,15 +23,38 @@ Date: August 2012
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <fcntl.h>
+#include <signal.h>
 
 #endif
 
 #include <util/unicode.h>
+#include <util/signal_catcher.h>
 
 #include "run.h"
 
 /*******************************************************************\
 
+Function: run_shell
+
+  Inputs:
+
+ Outputs:
+
+ Purpose:
+
+\*******************************************************************/
+
+int run_shell(const std::string &command)
+{
+  std::string shell="/bin/sh";
+  std::vector<std::string> argv;
+  argv.push_back(shell);
+  argv.push_back(command);
+  return run(shell, argv, "");
+}
+
+/*******************************************************************\
+
 Function: run
 
   Inputs:
@@ -89,15 +112,22 @@ int run(
     }
   }
 
-  pid_t childpid; /* variable to store the child's pid */
+  // temporarily suspend all signals
+  sigset_t new_mask, old_mask;
+  sigemptyset(&new_mask);
+  sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
 
   /* now create new process */
-  childpid = fork();
+  pid_t childpid = fork();
 
   if(childpid>=0) /* fork succeeded */
   {
     if(childpid==0) /* fork() returns 0 to the child process */
     {
+      // resume signals
+      remove_signal_catcher();
+      sigprocmask(SIG_SETMASK, &old_mask, NULL);
+      
       char **_argv=new char * [argv.size()+1];
       for(std::size_t i=0; i<argv.size(); i++)
         _argv[i]=strdup(argv[i].c_str());
@@ -106,12 +136,17 @@ int run(
 
       if(stdin_fd!=STDIN_FILENO)
         dup2(stdin_fd, STDIN_FILENO);
+
       execvp(what.c_str(), _argv);
+
       /* usually no return */
       return 1;
     }
     else /* fork() returns new pid to the parent process */
     {
+      // resume signals
+      sigprocmask(SIG_SETMASK, &old_mask, NULL);
+
       int status;     /* parent process: child's exit status */
 
       while(waitpid(childpid, &status, 0)==-1) /* wait for child to exit, and store its status */
@@ -133,8 +168,11 @@ int run(
   }
   else /* fork returns -1 on failure */
   {
-      if(stdin_fd!=STDIN_FILENO)
-        close(stdin_fd);
+    // resume signals
+    sigprocmask(SIG_SETMASK, &old_mask, NULL);
+
+    if(stdin_fd!=STDIN_FILENO)
+      close(stdin_fd);
 
     return 1;
   }

src/util/run.h

@@ -19,4 +19,6 @@ int run(
   const std::vector<std::string> &argv,
   const std::string &std_input);
 
+int run_shell(const std::string &command);
+
 #endif // CPROVER_UTIL_RUN_H