From: Philipp Gesang <philipp.gesang@intra2net.com>
Date: Wed, 3 Jan 2018 16:16:43 +0000 (+0100)
Subject: handle pipe termination separately depending on whether a shell is present
X-Git-Tag: v2.10~1^2~11
X-Git-Url: http://developer.intra2net.com/git/?p=libi2ncommon;a=commitdiff_plain;h=17b459b3c800f81801d70c9da644deb72b1230c5

handle pipe termination separately depending on whether a shell is present

Keep the child's pid around and wait() for it to perish in the
dtor of inpipestream. Return the error from closing the pipe or
terminating the process in the shell-free version. The mechanism
for retrieving the status does not allow to distinguish between
the two, so always prefer the latter.
---

diff --git a/src/pipestream.cpp b/src/pipestream.cpp
index e026851..eeca4f2 100644
--- a/src/pipestream.cpp
+++ b/src/pipestream.cpp
@@ -207,7 +207,7 @@ mk_argv (const std::vector<std::string> &command)
  *  @returns          A \c FILE* handle for streaming if successful, \c NULL
  *                    otherwise.
  */
-FILE *
+std::pair <pid_t, FILE *>
 inpipebuf::init_without_shell (const char *const *argv,
                                const bool out,
                                const bool err) const
@@ -247,6 +247,8 @@ inpipebuf::init_without_shell (const char *const *argv,
                 PIPE_CTOR_FAIL("dup2/stderr");
             }
 
+            close (pipefd [1]);
+
             errno = 0;
             if (execve (argv [0], const_cast <char *const *>(argv), NULL) == -1) {
                 PIPE_CTOR_FAIL("exec");
@@ -264,13 +266,14 @@ inpipebuf::init_without_shell (const char *const *argv,
         }
     }
 
-    return pipeobj;
+    return std::make_pair (childpid, pipeobj);
 }
 
 inpipebuf::inpipebuf(const char *const *command,
                      const bool out,
                      const bool err)
     : pipe (NULL) /* brr: shadowing global ident */
+    , pid (-1)
     , status_set (NULL)
     , exit_status (NULL)
 {
@@ -278,7 +281,9 @@ inpipebuf::inpipebuf(const char *const *command,
         PIPE_CTOR_FAIL("command");
     }
 
-    this->pipe = this->init_without_shell (command, out, err);
+    std::pair <pid_t, FILE *> tmp = this->init_without_shell (command, out, err);
+    this->pid  = tmp.first; /* no std::tie :/ */
+    this->pipe = tmp.second;
 
     setg (&buffer, &buffer, &buffer);
 }
@@ -287,6 +292,7 @@ inpipebuf::inpipebuf(const std::vector<std::string> &command,
                      const bool out,
                      const bool err)
     : pipe (NULL) /* brr: shadowing global ident */
+    , pid (-1)
     , status_set (NULL)
     , exit_status (NULL)
 {
@@ -299,7 +305,9 @@ inpipebuf::inpipebuf(const std::vector<std::string> &command,
         PIPE_CTOR_FAIL("malloc");
     }
 
-    this->pipe = this->init_without_shell (argv.get (), out, err);
+    std::pair <pid_t, FILE *> tmp = this->init_without_shell (argv.get (), out, err);
+    this->pid  = tmp.first;
+    this->pipe = tmp.second;
 
     setg (&buffer, &buffer, &buffer);
 }
@@ -307,10 +315,10 @@ inpipebuf::inpipebuf(const std::vector<std::string> &command,
 inpipebuf::inpipebuf(const std::string& command,
                      const bool _ignored_out,
                      const bool _ignored_err)
+    : pid (-1)
+    , status_set (NULL)
+    , exit_status (NULL)
 {
-    status_set = NULL;
-    exit_status = NULL;
-
     pipe = popen (command.c_str(), "r");
     if (pipe == NULL)
         throw EXCEPTION (pipestream_error, "can't open program or permission denied");
@@ -322,13 +330,47 @@ inpipebuf::inpipebuf(const std::string& command,
 inpipebuf::~inpipebuf()
 {
     if (pipe != NULL) {
-        int pclose_exit = pclose (pipe);
+        int status;
 
-        if (exit_status && pclose_exit != -1)
+        if (this->pid == -1)
         {
-            if (status_set)
-                *status_set = true;
-            *exit_status = pclose_exit;
+            errno = 0;
+            status = pclose (pipe);
+            if (status != -1) {
+                if (exit_status != NULL) {
+                    *exit_status = status;
+                    if (status_set != NULL) {
+                        *status_set = true;
+                    }
+                }
+            }
+        }
+        else
+        {
+            errno = 0;
+            status = fclose (pipe);
+            if (status != EOF) {
+                if (exit_status != NULL) {
+                    *exit_status = status; /* might be overwritten below */
+                    if (status_set != NULL) {
+                        *status_set = true;
+                    }
+                }
+            }
+
+            errno = 0;
+            while (waitpid (this->pid, &status, 0) == -1) {
+                if (errno != EINTR) {
+                    status = -1;
+                    break;
+                }
+            }
+            if (status != 0 && exit_status != NULL) {
+                *exit_status = status; /* might overwrite pipe status above */
+                if (status_set != NULL) {
+                    *status_set = true;
+                }
+            }
         }
 
         pipe = NULL;
diff --git a/src/pipestream.hxx b/src/pipestream.hxx
index fe9e8c0..f283d87 100644
--- a/src/pipestream.hxx
+++ b/src/pipestream.hxx
@@ -93,6 +93,7 @@ protected:
     char buffer;
 
     FILE *pipe;
+    pid_t pid;
 
     // "callback" variables for destructor to store exit status
     bool *status_set;
@@ -114,8 +115,9 @@ protected:
     virtual int_type underflow();
 
 private:
-    FILE *init_without_shell (const char *const *argv,
-                              const bool out, const bool err) const;
+    std::pair <pid_t, FILE *>
+    init_without_shell (const char *const *argv,
+                        const bool out, const bool err) const;
 };
 
 /** @brief stream around inpipebuf -- see comment there */