Add in a new FEATURE (off by default) BB_FEATURE_SH_BUILTINS_ALWAYS_WIN.

Make the sh default to using external commands when a path is provided.

4 files changed, 62 insertions, 3 deletions

diff --git a/Config.h b/Config.h
index b2baac2a2..c010671b5 100644
--- a/Config.h
+++ b/Config.h
@@ -234,6 +234,14 @@
 //among other thing.
 #define BB_FEATURE_SH_STANDALONE_SHELL
 //
+//When this is enabled, busybox shell builtins can be called using full path
+//names.  This causes builtins (which includes every single busybox command
+//when you enable BB_FEATURE_SH_STANDALONE_SHELL) to override real commands on
+//the filesystem.  When this is enabled, if you run /bin/cat, it will use
+//BusyBox cat even if /bin/cat exists on the filesystem and is _not_ busybox.
+//Some systems want this, others do not.  Choose wisely.  :-)
+//BB_FEATURE_SH_BUILTINS_ALWAYS_WIN
+//
 // Enable tab completion in the shell (not yet 
 // working very well -- so don't turn this on)
 //#define BB_FEATURE_SH_TAB_COMPLETION
diff --git a/lash.c b/lash.c
index 7a8810aef..d6ac1fc17 100644
--- a/lash.c
+++ b/lash.c
@@ -1216,7 +1216,24 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
                         /* Check if the command matches any busybox internal commands here */
                         while (a->name != 0) {
-                                if (strcmp(get_last_path_component(newJob->progs[i].argv[0]), a->name) == 0) {
+#ifdef BB_FEATURE_SH_BUILTINS_ALWAYS_WIN
+                                if (strcmp(get_last_path_component(newJob->progs[i].argv[0]),
+                                                        a->name) == 0) 
+#else
+                                        /* Check if the command matches any busybox internal
+                                         * commands ("applets") here.  Following discussions from
+                                         * November 2000 on busybox@opensource.lineo.com, don't use
+                                         * get_last_path_component().  This way explicit (with
+                                         * slashes) filenames will never be interpreted as an
+                                         * applet, just like with builtins.  This way the user can
+                                         * override an applet with an explicit filename reference.
+                                         * The only downside to this change is that an explicit
+                                         * /bin/foo invocation fill fork and exec /bin/foo, even if
+                                         * /bin/foo is a symlink to busybox.
+                                        */
+                                if (strcmp(newJob->progs[i].argv[0], a->name) == 0) 
+#endif
+                                {
                                         int argc_l;
                                         char** argv=newJob->progs[i].argv;
                                         for(argc_l=0;*argv!=NULL; argv++, argc_l++);
diff --git a/sh.c b/sh.c
index 7a8810aef..d6ac1fc17 100644
--- a/sh.c
+++ b/sh.c
@@ -1216,7 +1216,24 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
                         /* Check if the command matches any busybox internal commands here */
                         while (a->name != 0) {
-                                if (strcmp(get_last_path_component(newJob->progs[i].argv[0]), a->name) == 0) {
+#ifdef BB_FEATURE_SH_BUILTINS_ALWAYS_WIN
+                                if (strcmp(get_last_path_component(newJob->progs[i].argv[0]),
+                                                        a->name) == 0) 
+#else
+                                        /* Check if the command matches any busybox internal
+                                         * commands ("applets") here.  Following discussions from
+                                         * November 2000 on busybox@opensource.lineo.com, don't use
+                                         * get_last_path_component().  This way explicit (with
+                                         * slashes) filenames will never be interpreted as an
+                                         * applet, just like with builtins.  This way the user can
+                                         * override an applet with an explicit filename reference.
+                                         * The only downside to this change is that an explicit
+                                         * /bin/foo invocation fill fork and exec /bin/foo, even if
+                                         * /bin/foo is a symlink to busybox.
+                                        */
+                                if (strcmp(newJob->progs[i].argv[0], a->name) == 0) 
+#endif
+                                {
                                         int argc_l;
                                         char** argv=newJob->progs[i].argv;
                                         for(argc_l=0;*argv!=NULL; argv++, argc_l++);
diff --git a/shell/lash.c b/shell/lash.c
index 7a8810aef..d6ac1fc17 100644
--- a/shell/lash.c
+++ b/shell/lash.c
@@ -1216,7 +1216,24 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
                         /* Check if the command matches any busybox internal commands here */
                         while (a->name != 0) {
-                                if (strcmp(get_last_path_component(newJob->progs[i].argv[0]), a->name) == 0) {
+#ifdef BB_FEATURE_SH_BUILTINS_ALWAYS_WIN
+                                if (strcmp(get_last_path_component(newJob->progs[i].argv[0]),
+                                                        a->name) == 0) 
+#else
+                                        /* Check if the command matches any busybox internal
+                                         * commands ("applets") here.  Following discussions from
+                                         * November 2000 on busybox@opensource.lineo.com, don't use
+                                         * get_last_path_component().  This way explicit (with
+                                         * slashes) filenames will never be interpreted as an
+                                         * applet, just like with builtins.  This way the user can
+                                         * override an applet with an explicit filename reference.
+                                         * The only downside to this change is that an explicit
+                                         * /bin/foo invocation fill fork and exec /bin/foo, even if
+                                         * /bin/foo is a symlink to busybox.
+                                        */
+                                if (strcmp(newJob->progs[i].argv[0], a->name) == 0) 
+#endif
+                                {
                                         int argc_l;
                                         char** argv=newJob->progs[i].argv;
                                         for(argc_l=0;*argv!=NULL; argv++, argc_l++);