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authorLudovic Courtès <ludo@gnu.org>2020-05-11 16:32:24 +0200
committerLudovic Courtès <ludo@gnu.org>2020-05-14 17:21:27 +0200
commitfde2aec3f498d5ec6db2121d72068e2b203e86cd (patch)
treed0d3c9b723c3e694ca107cff9315075e8267ebf4 /gnu/packages/aux-files
parent80963744a242257921917df5a901dc343d3a93db (diff)
downloadguix-fde2aec3f498d5ec6db2121d72068e2b203e86cd.tar
guix-fde2aec3f498d5ec6db2121d72068e2b203e86cd.tar.gz
pack: Wrapper honors 'GUIX_EXECUTION_ENGINE' environment variable.
* gnu/packages/aux-files/run-in-namespace.c (struct engine): New type. (exec_default): New function. (engines): New variable. (execution_engine): New function. (main): Use it instead of calling 'exec_in_user_namespace' and 'exec_with_proot' directly. * tests/guix-pack-relocatable.sh: Add test with 'GUIX_EXECUTION_ENGINE'. * doc/guix.texi (Invoking guix pack): Document 'GUIX_EXECUTION_ENGINE'.
Diffstat (limited to 'gnu/packages/aux-files')
-rw-r--r--gnu/packages/aux-files/run-in-namespace.c78
1 files changed, 69 insertions, 9 deletions
diff --git a/gnu/packages/aux-files/run-in-namespace.c b/gnu/packages/aux-files/run-in-namespace.c
index 23e7875173..6beac7fd53 100644
--- a/gnu/packages/aux-files/run-in-namespace.c
+++ b/gnu/packages/aux-files/run-in-namespace.c
@@ -337,6 +337,71 @@ exec_with_proot (const char *store, int argc, char *argv[])
#endif
+/* Execution engines. */
+
+struct engine
+{
+ const char *name;
+ void (* exec) (const char *, int, char **);
+};
+
+static void
+buffer_stderr (void)
+{
+ static char stderr_buffer[4096];
+ setvbuf (stderr, stderr_buffer, _IOFBF, sizeof stderr_buffer);
+}
+
+/* The default engine. */
+static void
+exec_default (const char *store, int argc, char *argv[])
+{
+ /* Buffer stderr so that nothing's displayed if 'exec_in_user_namespace'
+ fails but 'exec_with_proot' works. */
+ buffer_stderr ();
+
+ exec_in_user_namespace (store, argc, argv);
+#ifdef PROOT_PROGRAM
+ exec_with_proot (store, argc, argv);
+#endif
+}
+
+/* List of supported engines. */
+static const struct engine engines[] =
+ {
+ { "default", exec_default },
+ { "userns", exec_in_user_namespace },
+#ifdef PROOT_PROGRAM
+ { "proot", exec_with_proot },
+#endif
+ { NULL, NULL }
+ };
+
+/* Return the "execution engine" to use. */
+static const struct engine *
+execution_engine (void)
+{
+ const char *str = getenv ("GUIX_EXECUTION_ENGINE");
+
+ if (str == NULL)
+ str = "default";
+
+ try:
+ for (const struct engine *engine = engines;
+ engine->name != NULL;
+ engine++)
+ {
+ if (strcmp (engine->name, str) == 0)
+ return engine;
+ }
+
+ fprintf (stderr, "%s: unsupported Guix execution engine; ignoring\n",
+ str);
+ str = "default";
+ goto try;
+}
+
+
int
main (int argc, char *argv[])
{
@@ -362,22 +427,17 @@ main (int argc, char *argv[])
if (strcmp (store, "@STORE_DIRECTORY@") != 0
&& lstat ("@WRAPPED_PROGRAM@", &statbuf) != 0)
{
- /* Buffer stderr so that nothing's displayed if 'exec_in_user_namespace'
- fails but 'exec_with_proot' works. */
- static char stderr_buffer[4096];
- setvbuf (stderr, stderr_buffer, _IOFBF, sizeof stderr_buffer);
+ const struct engine *engine = execution_engine ();
+ engine->exec (store, argc, argv);
- exec_in_user_namespace (store, argc, argv);
-#ifdef PROOT_PROGRAM
- exec_with_proot (store, argc, argv);
-#else
+ /* If we reach this point, that's because ENGINE failed to do the
+ job. */
fprintf (stderr, "\
This may be because \"user namespaces\" are not supported on this system.\n\
Consequently, we cannot run '@WRAPPED_PROGRAM@',\n\
unless you move it to the '@STORE_DIRECTORY@' directory.\n\
\n\
Please refer to the 'guix pack' documentation for more information.\n");
-#endif
return EXIT_FAILURE;
}