Avoid linking in printf/bsearch if possible. -20k for static bbox with

"basename", "true" and "false" only.

function                                             old     new   delta
full_write2_str                                        -      25     +25
bb_show_usage                                        183     202     +19
main                                                 883     898     +15
run_applet_and_exit                                  501     507      +6

2 files changed, 83 insertions, 27 deletions

diff --git a/applets/applet_tables.c b/applets/applet_tables.c
index 35b099eb4..17135ddc1 100644
--- a/applets/applet_tables.c
+++ b/applets/applet_tables.c
@@ -47,6 +47,7 @@ int main(int argc, char **argv)
 {
         int i;
         int ofs;
+        unsigned MAX_APPLET_NAME_LEN = 1;
 
         qsort(applets, NUM_APPLETS, sizeof(applets[0]), cmp_name);
 
@@ -71,18 +72,21 @@ int main(int argc, char **argv)
 
         puts("/* This is a generated file, don't edit */\n");
 
+        printf("#define NUM_APPLETS %u\n", NUM_APPLETS);
         if (NUM_APPLETS == 1) {
                 printf("#define SINGLE_APPLET_STR \"%s\"\n", applets[0].name);
-                printf("#define SINGLE_APPLET_MAIN %s_main\n\n", applets[0].name);
+                printf("#define SINGLE_APPLET_MAIN %s_main\n", applets[0].name);
         }
 
-        puts("const char applet_names[] ALIGN1 = \"\"");
+        puts("\nconst char applet_names[] ALIGN1 = \"\"");
         for (i = 0; i < NUM_APPLETS; i++) {
                 printf("\"%s\" \"\\0\"\n", applets[i].name);
+                if (MAX_APPLET_NAME_LEN < strlen(applets[i].name))
+                        MAX_APPLET_NAME_LEN = strlen(applets[i].name);
         }
         puts(";");
 
-        puts("int (*const applet_main[])(int argc, char **argv) = {");
+        puts("\nint (*const applet_main[])(int argc, char **argv) = {");
         for (i = 0; i < NUM_APPLETS; i++) {
                 printf("%s_main,\n", applets[i].main);
         }
@@ -113,8 +117,10 @@ int main(int argc, char **argv)
                 printf("0x%02x,\n", v);
                 i++;
         }
-        puts("};");
+        puts("};\n");
 #endif
 
+        printf("#define MAX_APPLET_NAME_LEN %u\n", MAX_APPLET_NAME_LEN);
+
         return 0;
 }
diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index a48a26003..ed7d3912b 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -12,6 +12,21 @@
  * Licensed under GPLv2 or later, see file License in this tarball for details.
  */
 
+/* We are trying to not use printf, this benefits the case when selected
+ * applets are really simple. Example:
+ *
+ * $ ./busybox
+ * ...
+ * Currently defined functions:
+ *         basename, false, true
+ *
+ * $ size busybox
+ *    text    data     bss     dec     hex filename
+ *    4473      52      72    4597    11f5 busybox
+ *
+ * FEATURE_INSTALLER or FEATURE_SUID will still link printf routines in. :(
+ */
+
 #include <assert.h>
 #include "busybox.h"
 
@@ -81,6 +96,11 @@ static const char *unpack_usage_messages(void)
 #endif /* FEATURE_COMPRESS_USAGE */
 
 
+static void full_write2_str(const char *str)
+{
+        full_write(2, str, strlen(str));
+}
+
 void bb_show_usage(void)
 {
         if (ENABLE_SHOW_USAGE) {
@@ -90,18 +110,14 @@ void bb_show_usage(void)
                 const char *usage_string = p = unpack_usage_messages();
 
                 if (*p == '\b') {
-                        write(2, "\nNo help available.\n\n",
-                                sizeof("\nNo help available.\n\n") - 1);
+                        full_write2_str("\nNo help available.\n\n");
                 } else {
-                        write(2, "\nUsage: "SINGLE_APPLET_STR" ",
-                                sizeof("\nUsage: "SINGLE_APPLET_STR" ") - 1);
-                        write(2, p, strlen(p));
-                        write(2, "\n\n", 2);
+                        full_write2_str("\nUsage: "SINGLE_APPLET_STR" ");
+                        full_write2_str(p);
+                        full_write2_str("\n\n");
                 }
                 dealloc_usage_messages((char*)usage_string);
 #else
-// TODO: in this case, stdio is sucked in by busybox_main() anyway...
-                const char *format_string;
                 const char *p;
                 const char *usage_string = p = unpack_usage_messages();
                 int ap = find_applet_by_name(applet_name);
@@ -112,32 +128,52 @@ void bb_show_usage(void)
                         while (*p++) continue;
                         ap--;
                 }
-                fprintf(stderr, "%s multi-call binary\n", bb_banner);
-                format_string = "\nUsage: %s %s\n\n";
+                full_write2_str(bb_banner);
+                full_write2_str(" multi-call binary\n");
                 if (*p == '\b')
-                        format_string = "\nNo help available.\n\n";
-                fprintf(stderr, format_string, applet_name, p);
+                        full_write2_str("\nNo help available.\n\n");
+                else {
+                        full_write2_str("\nUsage: ");
+                        full_write2_str(applet_name);
+                        full_write2_str(" ");
+                        full_write2_str(p);
+                        full_write2_str("\n\n");
+                }
                 dealloc_usage_messages((char*)usage_string);
 #endif
         }
         xfunc_die();
 }
 
-
+#if NUM_APPLETS > 8
 /* NB: any char pointer will work as well, not necessarily applet_names */
 static int applet_name_compare(const void *name, const void *v)
 {
         int i = (const char *)v - applet_names;
         return strcmp(name, APPLET_NAME(i));
 }
+#endif
 int find_applet_by_name(const char *name)
 {
+#if NUM_APPLETS > 8
         /* Do a binary search to find the applet entry given the name. */
         const char *p;
         p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
         if (!p)
                 return -1;
         return p - applet_names;
+#else
+        /* A version which does not pull in bsearch */
+        int i = 0;
+        const char *p = applet_names;
+        while (i < NUM_APPLETS) {
+                if (strcmp(name, p) == 0)
+                        return i;
+                p += strlen(p) + 1;
+                i++;
+        }
+        return -1;
+#endif
 }
 
 
@@ -604,10 +640,11 @@ static int busybox_main(char **argv)
                         get_terminal_width_height(0, &output_width, NULL);
                 }
                 /* leading tab and room to wrap */
-                output_width -= sizeof("start-stop-daemon, ") + 8;
+                output_width -= MAX_APPLET_NAME_LEN + 8;
 
-                printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
-                printf("Copyright (C) 1998-2007 Erik Andersen, Rob Landley, Denys Vlasenko\n"
+                full_write2_str(bb_banner); /* reuse const string... */
+                full_write2_str(" multi-call binary\n"
+                       "Copyright (C) 1998-2007 Erik Andersen, Rob Landley, Denys Vlasenko\n"
                        "and others. Licensed under GPLv2.\n"
                        "See source distribution for full notice.\n"
                        "\n"
@@ -623,14 +660,18 @@ static int busybox_main(char **argv)
                 col = 0;
                 a = applet_names;
                 while (*a) {
+                        int len;
                         if (col > output_width) {
-                                puts(",");
+                                full_write2_str(",\n");
                                 col = 0;
                         }
-                        col += printf("%s%s", (col ? ", " : "\t"), a);
-                        a += strlen(a) + 1;
+                        full_write2_str(col ? ", " : "\t");
+                        full_write2_str(a);
+                        len = strlen(a);
+                        col += len + 2;
+                        a += len + 1;
                 }
-                puts("\n");
+                full_write2_str("\n\n");
                 return 0;
         }
 
@@ -659,7 +700,11 @@ static int busybox_main(char **argv)
          * "#!/bin/busybox"-style wrappers */
         applet_name = bb_get_last_path_component_nostrip(argv[0]);
         run_applet_and_exit(applet_name, argv);
-        bb_error_msg_and_die("applet not found");
+
+        /*bb_error_msg_and_die("applet not found"); - sucks in printf */
+        full_write2_str(applet_name);
+        full_write2_str(": applet not found\n");
+        xfunc_die();
 }
 
 void run_applet_no_and_exit(int applet_no, char **argv)
@@ -701,7 +746,8 @@ int main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
 #if ENABLE_FEATURE_INDIVIDUAL
         /* Only one applet is selected by the user! */
-        lbb_prepare(SINGLE_APPLET_STR USE_FEATURE_INDIVIDUAL(, argv));
+        /* applet_names in this case is just "applet\0\0" */
+        lbb_prepare(applet_names USE_FEATURE_INDIVIDUAL(, argv));
         return SINGLE_APPLET_MAIN(argc, argv);
 #else
         lbb_prepare("busybox" USE_FEATURE_INDIVIDUAL(, argv));
@@ -721,6 +767,10 @@ int main(int argc ATTRIBUTE_UNUSED, char **argv)
         parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
 
         run_applet_and_exit(applet_name, argv);
-        bb_error_msg_and_die("applet not found");
+
+        /*bb_error_msg_and_die("applet not found"); - sucks in printf */
+        full_write2_str(applet_name);
+        full_write2_str(": applet not found\n");
+        xfunc_die();
 #endif
 }