[Xen-devel] [PATCH 03 of 13 RFC] libxl: add libxl__forkexec function to libxl_exec

[Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>]

# HG changeset patch
# User Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>
# Date 1326564288 -3600
# Node ID 74c7175a9bcfb48e4db3ad9e92bdb5eaf4f05c31
# Parent  b9a79fd1b93d44cf7b9ccf288c9f5df169adeb4d
libxl: add libxl__forkexec function to libxl_exec

Add a new function to libxl_exec that performs a fork and executes
the passed arguments using libxl__exec.

Signed-off-by: Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>

diff -r b9a79fd1b93d -r 74c7175a9bcf tools/libxl/libxl_exec.c
--- a/tools/libxl/libxl_exec.c  Mon Dec 26 22:25:02 2011 +0100
+++ b/tools/libxl/libxl_exec.c  Sat Jan 14 19:04:48 2012 +0100
@@ -454,6 +454,42 @@ int libxl__spawn_check(libxl__gc *gc, li
     return ERROR_FAIL;
 }
 
+int libxl__forkexec(libxl__gc *gc, int stdinfd, int stdoutfd,
+                    int stderrfd, const char *arg0, char **args,
+                    char **env, const char *what)
+{
+    libxl_ctx *ctx = libxl__gc_owner(gc);
+    int status;
+    int rc = 0;
+    pid_t pid = fork();
+
+    switch (pid) {
+    case -1:
+        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "fork failed\n");
+        rc = -1;
+        break;
+    case 0:
+        libxl__exec(stdinfd, stdoutfd, stderrfd, arg0, args, env);
+        /* libxl__exec never returns */
+    default:
+        while (waitpid(pid, &status, 0) < 0) {
+            if (errno != EINTR) {
+                LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, 
+                                 "waitpid failed for %s\n",
+                                 what);
+                rc = -1;
+                break;
+            }
+        }
+        if (status)
+            libxl_report_child_exitstatus(ctx, LIBXL__LOG_ERROR,
+                                          what, pid, status);
+        rc = status;
+        break;
+    }
+    return rc;
+}
+
 /*
  * Local variables:
  * mode: C
diff -r b9a79fd1b93d -r 74c7175a9bcf tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h      Mon Dec 26 22:25:02 2011 +0100
+++ b/tools/libxl/libxl_internal.h      Sat Jan 14 19:04:48 2012 +0100
@@ -453,6 +453,21 @@ _hidden int libxl__spawn_check(libxl__gc
 _hidden void libxl__exec(int stdinfd, int stdoutfd, int stderrfd,
                const char *arg0, char **args, char **env); // logs errors, 
never returns
 
+/*
+ * libxl__forkexec - Executes a file synchronously
+ * argv0: file name associated with the file being executed.
+ * args: list of arguments. See execvp(3) man page for more info.
+ * env: environment variables. See execvp(3) man page for more info.
+ *
+ * Returns -1 if the execution fails or the exit status, as reported
+ * by waitpid, on success.
+ *
+ * Logs errors.
+ */
+_hidden int libxl__forkexec(libxl__gc *gc, int stdinfd, int stdoutfd,
+                            int stderrfd, const char *arg0, char **args,
+                            char **env, const char *what);
+
 /* from xl_create */
 _hidden int libxl__domain_make(libxl__gc *gc, libxl_domain_create_info *info, 
uint32_t *domid);
 _hidden int libxl__domain_build(libxl__gc *gc,

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