From 8871308c48dd59046c0e1e318486be04ff20c278 Mon Sep 17 00:00:00 2001
From: "A. Wilcox" <AWilcox@Wilcox-Tech.com>
Date: Sat, 2 Nov 2019 17:50:11 -0500
Subject: hscript: Factor out FS exec stuff to run_command function

---
 hscript/disk.cc | 47 ++++---------------------------------------
 hscript/util.cc | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
 hscript/util.hh | 11 ++++++++++
 3 files changed, 73 insertions(+), 47 deletions(-)

diff --git a/hscript/disk.cc b/hscript/disk.cc
index 35936ac..a814761 100644
--- a/hscript/disk.cc
+++ b/hscript/disk.cc
@@ -22,14 +22,13 @@
 #   include "util/filesystem.hh"
 #   include <libudev.h>        /* udev_* */
 #   include <parted/parted.h>  /* ped_* */
-#   include <spawn.h>          /* posix_spawnp */
 #   include <sys/mount.h>      /* mount */
 #   include <sys/stat.h>       /* stat */
 #   include <sys/types.h>      /* S_* */
-#   include <sys/wait.h>       /* waitpid, W* */
 #   include <unistd.h>         /* access */
 #endif /* HAS_INSTALL_ENV */
 #include "disk.hh"
+#include "util.hh"
 #include "util/output.hh"
 
 using namespace Horizon::Keys;
@@ -877,47 +876,9 @@ bool Filesystem::execute(ScriptOptions opts) const {
     }
 
 #ifdef HAS_INSTALL_ENV
-    const char **argv = new const char*[args.size() + 2];
-    pid_t child;
-    int status;
-
-    argv[0] = cmd.c_str();
-    for(unsigned long index = 0; index < args.size(); index++) {
-        argv[index + 1] = args.at(index).c_str();
-    }
-    argv[args.size() + 1] = nullptr;
-
-    status = posix_spawnp(&child, cmd.c_str(), nullptr, nullptr,
-                          const_cast<char * const *>(argv), environ);
-    if(status != 0) {
-        /* extremely unlikely failure case */
-        output_error("installfile:" + std::to_string(this->lineno()),
-                     "fs: cannot fork", strerror(status));
-        delete[] argv;
-        return false;
-    }
-
-    delete[] argv;
-
-    if(waitpid(child, &status, 0) == -1) {
-        /* unlikely failure case */
-        output_error("installfile:" + std::to_string(this->lineno()),
-                     "fs: waitpid", strerror(errno));
-        return false;
-    }
-
-    if(!WIFEXITED(status)) {
-        output_error("installfile:" + std::to_string(this->lineno()),
-                     "fs: received fatal signal " +
-                     std::to_string(WTERMSIG(status)) + " while running " +
-                     cmd);
-        return false;
-    }
-
-    if(WEXITSTATUS(status) != 0) {
-        output_error("installfile:" + std::to_string(this->lineno()),
-                     "fs: " + cmd + " exited with status " +
-                     std::to_string(WEXITSTATUS(status)));
+    if(run_command(cmd, args) != 0) {
+        output_error("installfile:" + std::to_string(line),
+                     "fs: failed to create filesystem");
         return false;
     }
 #endif /* HAS_INSTALL_ENV */
diff --git a/hscript/util.cc b/hscript/util.cc
index 4a991c5..21d2356 100644
--- a/hscript/util.cc
+++ b/hscript/util.cc
@@ -11,12 +11,18 @@
  */
 
 #include <string>
+#include <vector>
 #ifdef HAVE_LIBCURL
-#    include <cstdio>       /* fopen */
-#    include <cstring>      /* strerror */
-#    include <curl/curl.h>  /* curl_* */
-#    include <errno.h>      /* errno */
+#    include <cstdio>           /* fopen */
+#    include <cstring>          /* strerror */
+#    include <curl/curl.h>      /* curl_* */
+#    include <errno.h>          /* errno */
 #endif /* HAVE_LIBCURL */
+#ifdef HAS_INSTALL_ENV
+#   include <spawn.h>           /* posix_spawnp */
+#   include <sys/wait.h>        /* waitpid, W* */
+#   include <unistd.h>          /* environ */
+#endif
 #include "util/output.hh"
 
 #ifdef HAVE_LIBCURL
@@ -59,3 +65,51 @@ bool download_file(const std::string &url, const std::string &path) {
     return false;
 }
 #endif /* HAVE_LIBCURL */
+
+int run_command(const std::string &cmd, const std::vector<std::string> &args) {
+#ifdef HAS_INSTALL_ENV
+    const char **argv = new const char*[args.size() + 2];
+    pid_t child;
+    int status;
+
+    argv[0] = cmd.c_str();
+    for(unsigned long index = 0; index < args.size(); index++) {
+        argv[index + 1] = args.at(index).c_str();
+    }
+    argv[args.size() + 1] = nullptr;
+
+    status = posix_spawnp(&child, cmd.c_str(), nullptr, nullptr,
+                          const_cast<char * const *>(argv), environ);
+    if(status != 0) {
+        /* extremely unlikely failure case */
+        output_error(cmd, "cannot fork", strerror(status));
+        delete[] argv;
+        return -1;
+    }
+
+    delete[] argv;
+
+    if(waitpid(child, &status, 0) == -1) {
+        /* unlikely failure case */
+        output_error(cmd, "waitpid", strerror(errno));
+        return -1;
+    }
+
+    if(!WIFEXITED(status)) {
+        output_error(cmd, "received fatal signal " +
+                     std::to_string(WTERMSIG(status)));
+        return -1;
+    }
+
+    if(WEXITSTATUS(status) != 0) {
+        output_error(cmd, "exited abnormally with status " +
+                     std::to_string(WEXITSTATUS(status)));
+        return false;
+    }
+
+    return WEXITSTATUS(status);
+#else /* !HAS_INSTALL_ENV */
+    output_error(cmd, "can't spawn processes in runtine environment");
+    return -1;
+#endif /* HAS_INSTALL_ENV */
+}
diff --git a/hscript/util.hh b/hscript/util.hh
index d350cd3..47da022 100644
--- a/hscript/util.hh
+++ b/hscript/util.hh
@@ -14,6 +14,7 @@
 #define HSCRIPT_UTIL_HH
 
 #include <string>
+#include <vector>
 
 /*! Download the contents of a URL to a path.
  * @param url       The URL to download.
@@ -22,4 +23,14 @@
  */
 bool download_file(const std::string &url, const std::string &path);
 
+/*! Run a command.
+ * @param cmd       The command to run.
+ * @param args      Arguments to pass to the command.
+ * @returns 0 if the command exited normally with status 0,
+ * the exit code if the command exited abnormally,
+ * -1 if the command signalled.
+ * @note Status of the command is output using +output_error+.
+ */
+int run_command(const std::string &cmd, const std::vector<std::string> &args);
+
 #endif /* !HSCRIPT_UTIL_HH */
-- 
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