Merge branch 'busybox' into merge

1 files changed, 140 insertions, 26 deletions

diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index 1d6a4b274..b71f2dd7e 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -140,32 +140,127 @@ void FAST_FUNC bb_show_usage(void)
         xfunc_die();
 }
 
-#if NUM_APPLETS > 8
-static int applet_name_compare(const void *name, const void *idx)
-{
-        int i = (int)(ptrdiff_t)idx - 1;
-        return strcmp(name, APPLET_NAME(i));
-}
-#endif
 int FAST_FUNC find_applet_by_name(const char *name)
 {
-#if NUM_APPLETS > 8
-        /* Do a binary search to find the applet entry given the name. */
+        unsigned i, max;
+        int j;
         const char *p;
-        p = bsearch(name, (void*)(ptrdiff_t)1, ARRAY_SIZE(applet_main), 1, applet_name_compare);
-        /*
-         * if (!p) return -1;
-         * ^^^^^^^^^^^^^^^^^^ the code below will do this if p == NULL :)
-         */
-        return (int)(ptrdiff_t)p - 1;
+
+/* The commented-out word-at-a-time code is ~40% faster, but +160 bytes.
+ * "Faster" here saves ~0.5 microsecond of real time - not worth it.
+ */
+#if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
+        uint32_t n32;
+
+        /* Handle all names < 2 chars long early */
+        if (name[0] == '\0')
+                return -1; /* "" is not a valid applet name */
+        if (name[1] == '\0') {
+                if (!ENABLE_TEST)
+                        return -1; /* 1-char name is not valid */
+                if (name[0] != ']')
+                        return -1; /* 1-char name which isn't "[" is not valid */
+                /* applet "[" is always applet #0: */
+                return 0;
+        }
+#endif
+
+        p = applet_names;
+        i = 0;
+#if KNOWN_APPNAME_OFFSETS <= 0
+        max = NUM_APPLETS;
 #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)
+        max = NUM_APPLETS * KNOWN_APPNAME_OFFSETS;
+        for (j = ARRAY_SIZE(applet_nameofs)-1; j >= 0; j--) {
+                const char *pp = applet_names + applet_nameofs[j];
+                if (strcmp(name, pp) >= 0) {
+                        //bb_error_msg("name:'%s' >= pp:'%s'", name, pp);
+                        p = pp;
+                        i = max - NUM_APPLETS;
+                        break;
+                }
+                max -= NUM_APPLETS;
+        }
+        max /= (unsigned)KNOWN_APPNAME_OFFSETS;
+        i /= (unsigned)KNOWN_APPNAME_OFFSETS;
+        //bb_error_msg("name:'%s' starting from:'%s' i:%u max:%u", name, p, i, max);
+#endif
+
+        /* Open-coded linear search without strcmp/strlen calls for speed */
+
+#if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
+        /* skip "[\0" name, it's surely not it */
+        if (ENABLE_TEST && LONE_CHAR(p, '['))
+                i++, p += 2;
+        /* All remaining applet names in p[] are at least 2 chars long */
+        /* name[] is also at least 2 chars long */
+
+        n32 = (name[0] << 0) | (name[1] << 8) | (name[2] << 16);
+        while (i < max) {
+                uint32_t p32;
+                char ch;
+
+                /* Quickly check match of the first 3 bytes */
+                move_from_unaligned32(p32, p);
+                p += 3;
+                if ((p32 & 0x00ffffff) != n32) {
+                        /* Most likely case: 3 first bytes do not match */
+                        i++;
+                        if ((p32 & 0x00ff0000) == '\0')
+                                continue; // p[2] was NUL
+                        p++;
+                        if ((p32 & 0xff000000) == '\0')
+                                continue; // p[3] was NUL
+                        /* p[0..3] aren't matching and none is NUL, check the rest */
+                        while (*p++ != '\0')
+                                continue;
+                        continue;
+                }
+
+                /* Unlikely branch: first 3 bytes ([0..2]) match */
+                if ((p32 & 0x00ff0000) == '\0') {
+                        /* name is 2-byte long, it is full match */
+                        //bb_error_msg("found:'%s' i:%u", name, i);
                         return i;
-                p += strlen(p) + 1;
+                }
+                /* Check remaining bytes [3..NUL] */
+                ch = (p32 >> 24);
+                j = 3;
+                while (ch == name[j]) {
+                        if (ch == '\0') {
+                                //bb_error_msg("found:'%s' i:%u", name, i);
+                                return i;
+                        }
+                        ch = *++p;
+                        j++;
+                }
+                /* Not a match. Skip it, including NUL */
+                while (ch != '\0')
+                        ch = *++p;
+                p++;
+                i++;
+        }
+        return -1;
+#else
+        while (i < max) {
+                char ch;
+                j = 0;
+                /* Do we see "name\0" in applet_names[p] position? */
+                while ((ch = *p) == name[j]) {
+                        if (ch == '\0') {
+                                //bb_error_msg("found:'%s' i:%u", name, i);
+                                return i; /* yes */
+                        }
+                        p++;
+                        j++;
+                }
+                /* No.
+                 * p => 1st non-matching char in applet_names[],
+                 * skip to and including NUL.
+                 */
+                while (ch != '\0')
+                        ch = *++p;
+                p++;
                 i++;
         }
         return -1;
@@ -588,6 +683,7 @@ static void install_links(const char *busybox, int use_symbolic_links,
          * busybox.h::bb_install_loc_t, or else... */
         int (*lf)(const char *, const char *);
         char *fpc;
+        const char *appname = applet_names;
         unsigned i;
         int rc;
 
@@ -598,7 +694,7 @@ static void install_links(const char *busybox, int use_symbolic_links,
         for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
                 fpc = concat_path_file(
                                 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
-                                APPLET_NAME(i));
+                                appname);
                 // debug: bb_error_msg("%slinking %s to busybox",
                 //              use_symbolic_links ? "sym" : "", fpc);
                 rc = lf(busybox, fpc);
@@ -606,6 +702,8 @@ static void install_links(const char *busybox, int use_symbolic_links,
                         bb_simple_perror_msg(fpc);
                 }
                 free(fpc);
+                while (*appname++ != '\0')
+                        continue;
         }
 }
 # else
@@ -769,7 +867,7 @@ void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
 
         /* Reinit some shared global data */
         xfunc_error_retval = EXIT_FAILURE;
-        applet_name = APPLET_NAME(applet_no);
+        applet_name = bb_get_last_path_component_nostrip(argv[0]);
 
         /* Special case. POSIX says "test --help"
          * should be no different from e.g. "test --foo".
@@ -800,11 +898,14 @@ void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
 
 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
 {
-        int applet = find_applet_by_name(name);
-        if (applet >= 0)
-                run_applet_no_and_exit(applet, argv);
+        int applet;
+
         if (is_prefixed_with(name, "busybox"))
                 exit(busybox_main(argv));
+        /* find_applet_by_name() search is more expensive, so goes second */
+        applet = find_applet_by_name(name);
+        if (applet >= 0)
+                run_applet_no_and_exit(applet, argv);
 }
 
 #endif /* !defined(SINGLE_APPLET_MAIN) */
@@ -817,6 +918,19 @@ int lbb_main(char **argv)
 int main(int argc UNUSED_PARAM, char **argv)
 #endif
 {
+#if 0
+        /* TODO: find a use for a block of memory between end of .bss
+         * and end of page. For example, I'm getting "_end:0x812e698 2408 bytes"
+         * - more than 2k of wasted memory (in this particular build)
+         * *per each running process*!
+         * (If your linker does not generate "_end" name, weak attribute
+         * makes &_end == NULL, end_len == 0 here.)
+         */
+        extern char _end[] __attribute__((weak));
+        unsigned end_len = (-(int)_end) & 0xfff;
+        printf("_end:%p %u bytes\n", &_end, end_len);
+#endif
+
         /* Tweak malloc for reduced memory consumption */
 #ifdef M_TRIM_THRESHOLD
         /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory