init: simpler handling of leading dash in commands

function                                             old     new   delta
init_exec                                            233     219     -14

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 12 insertions, 10 deletions

diff --git a/init/init.c b/init/init.c
index 0a0d503b5..a2cc3b5f5 100644
--- a/init/init.c
+++ b/init/init.c
@@ -401,20 +401,22 @@ static void init_exec(const char *command)
         char buf[COMMAND_SIZE + 6];  /* COMMAND_SIZE+strlen("exec ")+1 */
         int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
 
+        command += dash;
+
         /* See if any special /bin/sh requiring characters are present */
         if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
-                strcpy(buf, "exec ");
-                strcpy(buf + 5, command + dash); /* excluding "-" */
+                sprintf(buf, "exec %s", command); /* excluding "-" */
                 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
                 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
                 cmd[1] = (char*)"-c";
                 cmd[2] = buf;
                 cmd[3] = NULL;
+                command = LIBBB_DEFAULT_LOGIN_SHELL + 1;
         } else {
                 /* Convert command (char*) into cmd (char**, one word per string) */
                 char *word, *next;
                 int i = 0;
-                next = strcpy(buf, command); /* including "-" */
+                next = strcpy(buf, command - dash); /* command including "-" */
                 while ((word = strsep(&next, " \t")) != NULL) {
                         if (*word != '\0') { /* not two spaces/tabs together? */
                                 cmd[i] = word;
@@ -425,14 +427,14 @@ static void init_exec(const char *command)
         }
         /* If we saw leading "-", it is interactive shell.
          * Try harder to give it a controlling tty.
-         * And skip "-" in actual exec call. */
-        if (dash) {
+         */
+        if (ENABLE_FEATURE_INIT_SCTTY && dash) {
                 /* _Attempt_ to make stdin a controlling tty. */
-                if (ENABLE_FEATURE_INIT_SCTTY)
-                        ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
+                ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
         }
-        BB_EXECVP(cmd[0] + dash, cmd);
-        message(L_LOG | L_CONSOLE, "can't run '%s': %s", cmd[0], strerror(errno));
+        /* Here command never contains the dash, cmd[0] might */
+        BB_EXECVP(command, cmd);
+        message(L_LOG | L_CONSOLE, "can't run '%s': %s", command, strerror(errno));
         /* returns if execvp fails */
 }
 
diff --git a/shell/ash.c b/shell/ash.c
index 5671a524b..6f03ac1c6 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -13063,7 +13063,7 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
                 }
         }
 #endif
-        if (/* argv[0] && */ argv[0][0] == '-')
+        if (argv[0] && argv[0][0] == '-')
                 isloginsh = 1;
         if (isloginsh) {
                 state = 1;