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

by Cristian Ionescu-Idbohrn.

3 files changed, 16 insertions, 4 deletions

diff --git a/coreutils/Kbuild b/coreutils/Kbuild
index cb4543912..a5a2d4c26 100644
--- 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 eaaefaf29..78377e6a0 100644
--- 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 ebe961564..b7752369c 100644
--- 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. */