[PATCH v3 1/5] libxl: allow libxl__exec to take a parameter containing the env variables

[Roger Pau Monne <roger.pau@citrix.com>]

Add another parameter to libxl__exec call that contains the
environment variables to use when performing the execvp call.

Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
---
 tools/libxl/libxl.c            |    2 +-
 tools/libxl/libxl_bootloader.c |    4 ++--
 tools/libxl/libxl_dm.c         |    2 +-
 tools/libxl/libxl_exec.c       |    7 ++++++-
 tools/libxl/libxl_internal.h   |   13 ++++++++++++-
 5 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 42ac89f..f0372d0 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1253,7 +1253,7 @@ int libxl_vncviewer_exec(libxl_ctx *ctx, uint32_t domid, int autopass)
         args[2] = "-autopass";
     }
 
-    libxl__exec(autopass_fd, -1, -1, args[0], args);
+    libxl__exec(autopass_fd, -1, -1, args[0], args, NULL);
     abort();
 
  x_fail:
diff --git a/tools/libxl/libxl_bootloader.c b/tools/libxl/libxl_bootloader.c
index 2774062..7120dad 100644
--- a/tools/libxl/libxl_bootloader.c
+++ b/tools/libxl/libxl_bootloader.c
@@ -113,12 +113,12 @@ static int open_xenconsoled_pty(int *master, int *slave, char *slave_path, size_
 static pid_t fork_exec_bootloader(int *master, const char *arg0, char **args)
 {
     struct termios termattr;
+    char *env[] = {"TERM", "vt100", NULL};
     pid_t pid = forkpty(master, NULL, NULL, NULL);
     if (pid == -1)
         return -1;
     else if (pid == 0) {
-        setenv("TERM", "vt100", 1);
-        libxl__exec(-1, -1, -1, arg0, args);
+        libxl__exec(-1, -1, -1, arg0, args, env);
         return -1;
     }
 
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index e25a767..15e24b9 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -994,7 +994,7 @@ retry_transaction:
         goto out_close;
     if (!rc) { /* inner child */
         setsid();
-        libxl__exec(null, logfile_w, logfile_w, dm, args);
+        libxl__exec(null, logfile_w, logfile_w, dm, args, NULL);
     }
 
     rc = 0;
diff --git a/tools/libxl/libxl_exec.c b/tools/libxl/libxl_exec.c
index b10e79f..be9e407 100644
--- a/tools/libxl/libxl_exec.c
+++ b/tools/libxl/libxl_exec.c
@@ -72,7 +72,7 @@ static void check_open_fds(const char *what)
 }
 
 void libxl__exec(int stdinfd, int stdoutfd, int stderrfd, const char *arg0,
-                char **args)
+                char **args, char **env)
      /* call this in the child */
 {
     if (stdinfd != -1)
@@ -95,6 +95,11 @@ void libxl__exec(int stdinfd, int stdoutfd, int stderrfd, const char *arg0,
     /* in case our caller set it to IGN.  subprocesses are entitled
      * to assume they got DFL. */
 
+    if (env != NULL) {
+        for (int i = 0; env[i] != NULL && env[i+1] != NULL; i += 2) {
+            setenv(env[i], env[i+1], 1);
+        }
+    }
     execvp(arg0, args);
 
     fprintf(stderr, "libxl: cannot execute %s: %s\n", arg0, strerror(errno));
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index d524945..9e15f95 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -952,8 +952,19 @@ _hidden int libxl__spawn_check(libxl__gc *gc,
 
  /* low-level stuff, for synchronous subprocesses etc. */
 
+/*
+ * env should be passed using the following format,
+ *
+ * env[0]: name of env variable
+ * env[1]: value of env variable
+ *
+ * So it efectively becomes something like:
+ * export env[0]=env[1]
+ *
+ * The last entry of the array always has to be NULL.
+ */
 _hidden void libxl__exec(int stdinfd, int stdoutfd, int stderrfd,
-               const char *arg0, char **args); // logs errors, never returns
+               const char *arg0, char **args, char **env); // logs errors, never returns
 
 /* from xl_create */
 _hidden int libxl__domain_make(libxl__gc *gc,
-- 
1.7.7.5 (Apple Git-26)