kill: optimizations for single-applet build

* Fix a bug with a configuration in which the shell's kill builtin
  would be mistreated as a killall command (i.e. '-q' works, and
  'kill process_name' succeeds when it shouldn't):

    CONFIG_ASH_JOB_CONTROL=y
    CONFIG_HUSH_KILL=y
    # CONFIG_KILL is not set
    CONFIG_KILLALL=y
    # CONFIG_KILLALL5 is not set

* Optimize out unneeded code when the relevant applets are not
  selected.

* Move kbuild lines about shells' kill builtins from Kbuild.src to
  kill.c, to accompany the new HAVE_SH_KILL macro. I hope this would
  make maintanence a little bit easier.

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 28 insertions, 21 deletions

diff --git a/procps/Kbuild.src b/procps/Kbuild.src
index dedef8881..6b4fb7470 100644
--- a/procps/Kbuild.src
+++ b/procps/Kbuild.src
@@ -7,6 +7,3 @@
 lib-y:=
 
 INSERT
-
-lib-$(CONFIG_ASH_JOB_CONTROL) += kill.o  # used for built-in kill by ash
-lib-$(CONFIG_HUSH_KILL) += kill.o  # used for built-in kill by hush
diff --git a/procps/kill.c b/procps/kill.c
index 7c0822542..0ef1716a4 100644
--- a/procps/kill.c
+++ b/procps/kill.c
@@ -92,28 +92,34 @@
  * This is needed to avoid collision with kill -9 ... syntax
  */
 
+//kbuild:lib-$(CONFIG_ASH_JOB_CONTROL) += kill.o
+//kbuild:lib-$(CONFIG_HUSH_KILL) += kill.o
+
+#define SH_KILL (ENABLE_ASH_JOB_CONTROL || ENABLE_HUSH_KILL)
+/* If shells want to have "kill", for ifdefs it's like ENABLE_KILL=1 */
+#if SH_KILL
+# undef  ENABLE_KILL
+# define ENABLE_KILL 1
+#endif
+#define KILL_APPLET_CNT (ENABLE_KILL + ENABLE_KILLALL + ENABLE_KILLALL5)
+
 int kill_main(int argc UNUSED_PARAM, char **argv)
 {
         char *arg;
         pid_t pid;
         int signo = SIGTERM, errors = 0, quiet = 0;
-#if ENABLE_KILL && !ENABLE_KILLALL && !ENABLE_KILLALL5
-# define killall  0
-# define killall5 0
-#elif !ENABLE_KILL && ENABLE_KILLALL && !ENABLE_KILLALL5
-# define killall  1
-# define killall5 0
-#elif !ENABLE_KILL && !ENABLE_KILLALL && ENABLE_KILLALL5
-# define killall  0
-# define killall5 1
+
+#if KILL_APPLET_CNT == 1
+# define is_killall  ENABLE_KILLALL
+# define is_killall5 ENABLE_KILLALL5
 #else
 /* How to determine who we are? find 3rd char from the end:
  * kill, killall, killall5
  *  ^i       ^a        ^l  - it's unique
  * (checking from the start is complicated by /bin/kill... case) */
         const char char3 = argv[0][strlen(argv[0]) - 3];
-# define killall  (ENABLE_KILLALL && char3 == 'a')
-# define killall5 (ENABLE_KILLALL5 && char3 == 'l')
+# define is_killall  (ENABLE_KILLALL  && char3 == 'a')
+# define is_killall5 (ENABLE_KILLALL5 && char3 == 'l')
 #endif
 
         /* Parse any options */
@@ -162,7 +168,7 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
         }
 
         /* The -q quiet option */
-        if (killall && arg[1] == 'q' && arg[2] == '\0') {
+        if (is_killall && arg[1] == 'q' && arg[2] == '\0') {
                 quiet = 1;
                 arg = *++argv;
                 if (!arg)
@@ -174,7 +180,7 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
         arg++; /* skip '-' */
 
         /* -o PID? (if present, it always is at the end of command line) */
-        if (killall5 && arg[0] == 'o')
+        if (is_killall5 && arg[0] == 'o')
                 goto do_it_now;
 
         if (argv[1] && arg[0] == 's' && arg[1] == '\0') { /* -s SIG? */
@@ -190,7 +196,7 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
  do_it_now:
         pid = getpid();
 
-        if (killall5) {
+        if (is_killall5) {
                 pid_t sid;
                 procps_status_t* p = NULL;
                 /* compat: exitcode 2 is "no one was signaled" */
@@ -248,13 +254,14 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
                 return ret;
         }
 
+#if ENABLE_KILL || ENABLE_KILLALL
         /* Pid or name is required for kill/killall */
         if (!arg) {
                 bb_error_msg("you need to specify whom to kill");
                 return EXIT_FAILURE;
         }
 
-        if (killall) {
+        if (!ENABLE_KILL || is_killall) {
                 /* Looks like they want to do a killall.  Do that */
                 do {
                         pid_t* pidList;
@@ -282,10 +289,12 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
                 } while (arg);
                 return errors;
         }
+#endif
 
+#if ENABLE_KILL
         /* Looks like they want to do a kill. Do that */
         while (arg) {
-#if ENABLE_ASH_JOB_CONTROL || ENABLE_HUSH_KILL
+# if SH_KILL
                 /*
                  * We need to support shell's "hack formats" of
                  * " -PRGP_ID" (yes, with a leading space)
@@ -307,7 +316,7 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
                         }
                         arg = end; /* can only point to ' ' or '\0' now */
                 }
-#else
+# else /* ENABLE_KILL but !SH_KILL */
                 pid = bb_strtoi(arg, NULL, 10);
                 if (errno) {
                         bb_error_msg("invalid number '%s'", arg);
@@ -316,8 +325,9 @@ int kill_main(int argc UNUSED_PARAM, char **argv)
                         bb_perror_msg("can't kill pid %d", (int)pid);
                         errors++;
                 }
-#endif
+# endif
                 arg = *++argv;
         }
         return errors;
+#endif
 }