ash: optional printf builtin. +25 bytes if off, +35 if on.

by Cristian Ionescu-Idbohrn.

diff --git a/coreutils/Kbuild b/coreutils/Kbuild
index cb45439..a5a2d4c 100644 (file)
--- a/coreutils/Kbuild
+++ b/coreutils/Kbuild
@@ -54,6 +54,7 @@ lib-$(CONFIG_NOHUP)     += nohup.o
 lib-$(CONFIG_OD)        += od.o
 lib-$(CONFIG_PRINTENV)  += printenv.o
 lib-$(CONFIG_PRINTF)    += printf.o
+lib-$(CONFIG_ASH_BUILTIN_PRINTF) += printf.o
 lib-$(CONFIG_PWD)       += pwd.o
 lib-$(CONFIG_READLINK)  += readlink.o
 lib-$(CONFIG_REALPATH)  += realpath.o

diff --git a/coreutils/chown.c b/coreutils/chown.c
index eaaefaf..78377e6 100644 (file)
--- a/coreutils/chown.c
+++ b/coreutils/chown.c
@@ -61,7 +61,6 @@ static int fileAction(const char *fileName, struct stat *statbuf,
        return FALSE;
 }
 
-int chown_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int chown_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
        int retval = EXIT_SUCCESS;

diff --git a/coreutils/printf.c b/coreutils/printf.c
index ebe9615..b775236 100644 (file)
--- a/coreutils/printf.c
+++ b/coreutils/printf.c
@@ -193,6 +193,7 @@ static char **print_formatted(char *f, char **argv)
        unsigned direc_length;  /* Length of % directive.  */
        int field_width;        /* Arg to first '*', or -1 if none.  */
        int precision;          /* Arg to second '*', or -1 if none.  */
+       char **saved_argv = argv;
 
        for (; *f; ++f) {
                switch (*f) {
@@ -264,8 +265,9 @@ static char **print_formatted(char *f, char **argv)
                                                        precision, "");
                        break;
                case '\\':
-                       if (*++f == 'c')
-                               exit(EXIT_SUCCESS);
+                       if (*++f == 'c') {
+                               return saved_argv; /* causes main() to exit */
+                       }
                        bb_putchar(bb_process_escape_sequence((const char **)&f));
                        f--;
                        break;
@@ -277,12 +279,22 @@ static char **print_formatted(char *f, char **argv)
        return argv;
 }
 
-int printf_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int printf_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
        char *format;
        char **argv2;
 
+       /* We must check that stdout is not closed.
+        * The reason for this is highly non-obvious. printf_main is used from shell.
+        * Shell must correctly handle 'printf "%s" foo'
+        * if stdout is closed. With stdio, output gets shoveled into
+        * stdout buffer, and even fflush cannot clear it out. It seems that
+        * even if libc receives EBADF on write attempts, it feels determined
+        * to output data no matter what. So it will try later,
+        * and possibly will clobber future output. Not good. */
+       if (dup2(1, 1) != 1)
+               return -1;
+
        /* bash builtin errors out on "printf '-%s-\n' foo",
         * coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
         * We will mimic coreutils. */

diff --git a/include/applets.h b/include/applets.h
index 17113df..e7fc3c0 100644 (file)
--- a/include/applets.h
+++ b/include/applets.h
@@ -275,7 +275,7 @@ USE_PIVOT_ROOT(APPLET(pivot_root, _BB_DIR_SBIN, _BB_SUID_NEVER))
 USE_PKILL(APPLET_ODDNAME(pkill, pgrep, _BB_DIR_USR_BIN, _BB_SUID_NEVER, pkill))
 USE_HALT(APPLET_ODDNAME(poweroff, halt, _BB_DIR_SBIN, _BB_SUID_NEVER, poweroff))
 USE_PRINTENV(APPLET(printenv, _BB_DIR_BIN, _BB_SUID_NEVER))
-USE_PRINTF(APPLET(printf, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
+USE_PRINTF(APPLET_NOFORK(printf, printf, _BB_DIR_USR_BIN, _BB_SUID_NEVER, printf))
 USE_PS(APPLET(ps, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_PSCAN(APPLET(pscan, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_PWD(APPLET_NOFORK(pwd, pwd, _BB_DIR_BIN, _BB_SUID_NEVER, pwd))

diff --git a/include/libbb.h b/include/libbb.h
index 947f28d..c79cd8b 100644 (file)
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -878,13 +878,16 @@ extern void bb_verror_msg(const char *s, va_list p, const char *strerr);
 #endif
 
 
-/* applets which are useful from another applets */
+/* Applets which are useful from another applets */
 int bb_cat(char** argv);
-/* If shell needs them, these three "exist" even if not enabled as applets */
+/* If shell needs them, they exist even if not enabled as applets */
 int echo_main(int argc, char** argv) USE_ECHO(MAIN_EXTERNALLY_VISIBLE);
+int printf_main(int argc, char **argv) USE_PRINTF(MAIN_EXTERNALLY_VISIBLE);
 int test_main(int argc, char **argv) USE_TEST(MAIN_EXTERNALLY_VISIBLE);
 int kill_main(int argc, char **argv) USE_KILL(MAIN_EXTERNALLY_VISIBLE);
-int chown_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+/* Similar, but used by chgrp, not shell */
+int chown_main(int argc, char **argv) USE_CHOWN(MAIN_EXTERNALLY_VISIBLE);
+/* Don't need USE_xxx() guard for these */
 int gunzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int bunzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int bbunpack(char **argv,

diff --git a/miscutils/last.c b/miscutils/last.c
index a8800bf..612f504 100644 (file)
--- a/miscutils/last.c
+++ b/miscutils/last.c
@@ -10,6 +10,9 @@
 #include "libbb.h"
 #include <utmp.h>
 
+/* NB: ut_name and ut_user are the same field, use only one name (ut_user)
+ * to reduce confusion */
+
 #ifndef SHUTDOWN_TIME
 #  define SHUTDOWN_TIME 254
 #endif

diff --git a/miscutils/last_fancy.c b/miscutils/last_fancy.c
index 0dba9dc..2b7fee6 100644 (file)
--- a/miscutils/last_fancy.c
+++ b/miscutils/last_fancy.c
@@ -10,6 +10,9 @@
 #include "libbb.h"
 #include <utmp.h>
 
+/* NB: ut_name and ut_user are the same field, use only one name (ut_user)
+ * to reduce confusion */
+
 #ifndef SHUTDOWN_TIME
 #  define SHUTDOWN_TIME 254
 #endif

diff --git a/shell/Config.in b/shell/Config.in
index 94ffa09..a670162 100644 (file)
--- a/shell/Config.in
+++ b/shell/Config.in
@@ -114,6 +114,13 @@ config ASH_BUILTIN_ECHO
        help
          Enable support for echo, builtin to ash.
 
+config ASH_BUILTIN_PRINTF
+       bool "Builtin version of 'printf'"
+       default y
+       depends on ASH
+       help
+         Enable support for printf, builtin to ash.
+
 config ASH_BUILTIN_TEST
        bool "Builtin version of 'test'"
        default y

diff --git a/shell/ash.c b/shell/ash.c
index 20b93f3..31beb86 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -8488,17 +8488,18 @@ static int ulimitcmd(int, char **);
  * Apart from the above, [[ expr ]] should work as [ expr ]
  */
 
-#define testcmd test_main
-#define echocmd echo_main
+#define echocmd   echo_main
+#define printfcmd printf_main
+#define testcmd   test_main
 
 /* Keep these in proper order since it is searched via bsearch() */
 static const struct builtincmd builtintab[] = {
        { BUILTIN_SPEC_REG      ".", dotcmd },
        { BUILTIN_SPEC_REG      ":", truecmd },
 #if ENABLE_ASH_BUILTIN_TEST
-       { BUILTIN_REGULAR       "[", testcmd },
+       { BUILTIN_REGULAR       "[", testcmd },
 #if ENABLE_ASH_BASH_COMPAT
-       { BUILTIN_REGULAR       "[[", testcmd },
+       { BUILTIN_REGULAR       "[[", testcmd },
 #endif
 #endif
 #if ENABLE_ASH_ALIAS
@@ -8540,6 +8541,9 @@ static const struct builtincmd builtintab[] = {
        { BUILTIN_NOSPEC        "let", letcmd },
 #endif
        { BUILTIN_ASSIGN        "local", localcmd },
+#if ENABLE_ASH_BUILTIN_PRINTF
+       { BUILTIN_REGULAR       "printf", printfcmd },
+#endif
        { BUILTIN_NOSPEC        "pwd", pwdcmd },
        { BUILTIN_REGULAR       "read", readcmd },
        { BUILTIN_SPEC_REG_ASSG "readonly", exportcmd },
@@ -8548,7 +8552,7 @@ static const struct builtincmd builtintab[] = {
        { BUILTIN_SPEC_REG      "shift", shiftcmd },
        { BUILTIN_SPEC_REG      "source", dotcmd },
 #if ENABLE_ASH_BUILTIN_TEST
-       { BUILTIN_REGULAR       "test", testcmd },
+       { BUILTIN_REGULAR       "test", testcmd },
 #endif
        { BUILTIN_SPEC_REG      "times", timescmd },
        { BUILTIN_SPEC_REG      "trap", trapcmd },