ash: speed up NOFORK code in ash by eliminating second find_applet().

some code reduction along the way. function old new delta run_list 1971 1981 +10 run_nofork_applet_prime 181 182 +1 unsetcmd 97 96 -1 delete_cmd_entry 54 53 -1 describe_command 399 397 -2 cmdlookup 152 150 -2 evaltreenr 602 599 -3 evaltree 602 599 -3 clearcmdentry 101 98 -3 cdcmd 675 672 -3 hashcmd 305 301 -4 find_command 933 910 -23 evalcommand 1371 1229 -142 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 2/11 up/down: 11/-187) Total: -176 bytes
author: Denis Vlasenko <vda.linux@googlemail.com> 2008-04-13 02:25:53 +0000
committer: Denis Vlasenko <vda.linux@googlemail.com> 2008-04-13 02:25:53 +0000
commit: 7465dbcf2a4c0a0983d40e5c0f5c057d2ed04125 (patch)
tree: fdbbbaab05b45dfb3f67e62e23863e4cc899584b
parent: f78a656f7c287c0963d985490b3e77751b4a81bc (diff)
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3 files changed, 34 insertions, 23 deletions
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 1567d89be..2c4c930b2 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -146,6 +146,15 @@ int run_nofork_applet_prime(struct nofork_save_area *old, int applet_no, char **
                memcpy(tmp_argv, argv, (argc+1) * sizeof(tmp_argv[0]));
                /* Finally we can call NOFORK applet's main() */
                rc = applet_main[applet_no](argc, tmp_argv);
+        /* The whole reason behind nofork_save_area is that <applet>_main
+         * may exit non-locally! For example, in hush Ctrl-Z tries to
+         * (modulo bugs) to dynamically create child (backgrounded task)
+         * if it detects that Ctrl-Z was pressed when a NOFORK was running!
+         * Testcase: interactive "rm -i".
+         * Don't fool yourself into thinking "and <applet>_main() returns
+         * quickly here" and removing "useless" nofork_save_area code. */
        } else { /* xfunc died in NOFORK applet */
                /* in case they meant to return 0... */
                if (rc == -2222)
@@ -154,7 +163,7 @@ int run_nofork_applet_prime(struct nofork_save_area *old, int applet_no, char **
        /* Restoring globals */
        restore_nofork_data(old);
-        return rc;
+        return rc & 0xff; /* don't confuse people with "exitcodes" >255 */
 }
 int run_nofork_applet(int applet_no, char **argv)
diff --git a/shell/ash.c b/shell/ash.c
index cc61401d1..409d084cf 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -6828,9 +6828,13 @@ struct builtincmd {
 #define IS_BUILTIN_ASSIGN(b)  ((b)->name[0] & 4)
 struct cmdentry {
-        int cmdtype;
+        smallint cmdtype;       /* CMDxxx */
        union param {
                int index;
+                /* index >= 0 for commands without path (slashes) */
+                /* (TODO: what exactly does the value mean? PATH position?) */
+                /* index == -1 for commands with slashes */
+                /* index == (-2 - applet_no) for NOFORK applets */
                const struct builtincmd *cmd;
                struct funcnode *func;
        } u;
@@ -6867,7 +6871,7 @@ static void find_command(char *, struct cmdentry *, int, const char *);
 struct tblentry {
        struct tblentry *next;  /* next entry in hash chain */
        union param param;      /* definition of builtin function */
-        short cmdtype;          /* index identifying command */
+        smallint cmdtype;       /* CMDxxx */
        char rehash;            /* if set, cd done since entry created */
        char cmdname[ARB];      /* name of command */
 };
@@ -7355,7 +7359,7 @@ describe_command(char *command, int describe_command_verbose)
        case CMDNORMAL: {
                int j = entry.u.index;
                char *p;
-                if (j == -1) {
+                if (j < 0) {
                        p = command;
                } else {
                        do {
@@ -8747,22 +8751,17 @@ evalcommand(union node *cmd, int flags)
        /* Execute the command. */
        switch (cmdentry.cmdtype) {
        default:
 #if ENABLE_FEATURE_SH_NOFORK
-                {
+        {
-                /* TODO: don't rerun find_applet_by_name, find_command
+                /* find_command() encodes applet_no as (-2 - applet_no) */
-                 * already did it. Make it save applet_no somewhere */
+                int applet_no = (- cmdentry.u.index - 2);
-                int applet_no = find_applet_by_name(argv[0]);
                if (applet_no >= 0 && APPLET_IS_NOFORK(applet_no)) {
-                        struct nofork_save_area nofork_save;
                        listsetvar(varlist.list, VEXPORT|VSTACK);
-                        save_nofork_data(&nofork_save);
+                        /* run <applet>_main() */
-                        /* run <applet>_main(), then restore nofork_save_area */
+                        exitstatus = run_nofork_applet(applet_no, argv);
-                        exitstatus = run_nofork_applet_prime(&nofork_save, applet_no, argv) & 0xff;
                        break;
                }
-                }
+        }
 #endif
                /* Fork off a child process if necessary. */
@@ -11618,10 +11617,13 @@ find_command(char *name, struct cmdentry *entry, int act, const char *path)
        }
 #if ENABLE_FEATURE_SH_STANDALONE
-        if (find_applet_by_name(name) >= 0) {
+        {
-                entry->cmdtype = CMDNORMAL;
+                int applet_no = find_applet_by_name(name);
-                entry->u.index = -1;
+                if (applet_no >= 0) {
-                return;
+                        entry->cmdtype = CMDNORMAL;
+                        entry->u.index = -2 - applet_no;
+                        return;
+                }
        }
 #endif
@@ -12691,7 +12693,7 @@ is_right_associativity(operator prec)
                || prec == PREC(TOK_CONDITIONAL));
 }
-typedef struct ARITCH_VAR_NUM {
+typedef struct {
        arith_t val;
        arith_t contidional_second_val;
        char contidional_second_val_initialized;
@@ -12699,9 +12701,9 @@ typedef struct ARITCH_VAR_NUM {
                           else is variable name */
 } v_n_t;
-typedef struct CHK_VAR_RECURSIVE_LOOPED {
+typedef struct chk_var_recursive_looped_t {
        const char *var;
-        struct CHK_VAR_RECURSIVE_LOOPED *next;
+        struct chk_var_recursive_looped_t *next;
 } chk_var_recursive_looped_t;
 static chk_var_recursive_looped_t *prev_chk_var_recursive;
diff --git a/shell/hush.c b/shell/hush.c
index 545367cb6..aa740f1b4 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1861,7 +1861,7 @@ static int run_pipe(struct pipe *pi)
                                //sp: if (child->sp)
                                argv_expanded = expand_strvec_to_strvec(argv + i);
                                debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]);
-                                rcode = run_nofork_applet_prime(&nofork_save, a, argv_expanded) & 0xff;
+                                rcode = run_nofork_applet_prime(&nofork_save, a, argv_expanded);
                                free(argv_expanded);
                                restore_redirects(squirrel);
                                debug_printf_exec("run_pipe return %d\n", rcode);
author	Denis Vlasenko <vda.linux@googlemail.com>	2008-04-13 02:25:53 +0000
committer	Denis Vlasenko <vda.linux@googlemail.com>	2008-04-13 02:25:53 +0000
commit	7465dbcf2a4c0a0983d40e5c0f5c057d2ed04125 (patch)
tree	fdbbbaab05b45dfb3f67e62e23863e4cc899584b
parent	f78a656f7c287c0963d985490b3e77751b4a81bc (diff)
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