libbb: reduce the overhead of single parameter bb_error_msg() calls

Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().

This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.

Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.

This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.

The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):

Arm:     -92 bytes
MIPS:    -52 bytes
PPC:   -1836 bytes
x86_64: -938 bytes

Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.

Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 17 insertions, 17 deletions

diff --git a/shell/hush.c b/shell/hush.c
index f82747f..19b97e2 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1398,7 +1398,7 @@ static void syntax_error(unsigned lineno UNUSED_PARAM, const char *msg)
 	if (msg)
 		bb_error_msg("syntax error: %s", msg);
 	else
-		bb_error_msg("syntax error");
+		bb_simple_error_msg("syntax error");
 	die_if_script();
 }
 
@@ -1637,7 +1637,7 @@ static int refill_HFILE_and_getc(HFILE *fp)
 	fp->cur = fp->buf;
 	n = safe_read(fp->fd, fp->buf, sizeof(fp->buf));
 	if (n < 0) {
-		bb_perror_msg("read error");
+		bb_simple_perror_msg("read error");
 		n = 0;
 	}
 	fp->end = fp->buf + n;
@@ -2282,7 +2282,7 @@ static int set_local_var(char *str, unsigned flags)
 
 	eq_sign = strchr(str, '=');
 	if (HUSH_DEBUG && !eq_sign)
-		bb_error_msg_and_die("BUG in setvar");
+		bb_simple_error_msg_and_die("BUG in setvar");
 
 	name_len = eq_sign - str + 1; /* including '=' */
 	cur_pp = &G.top_var;
@@ -2505,7 +2505,7 @@ static void set_vars_and_save_old(char **strings)
 
 		eq = strchr(*s, '=');
 		if (HUSH_DEBUG && !eq)
-			bb_error_msg_and_die("BUG in varexp4");
+			bb_simple_error_msg_and_die("BUG in varexp4");
 		var_pp = get_ptr_to_local_var(*s, eq - *s);
 		if (var_pp) {
 			var_p = *var_pp;
@@ -4246,7 +4246,7 @@ static int parse_redir_right_fd(o_string *as_string, struct in_str *input)
 
 //TODO: this is the place to catch ">&file" bashism (redirect both fd 1 and 2)
 
-	bb_error_msg("ambiguous redirect");
+	bb_simple_error_msg("ambiguous redirect");
 	return REDIRFD_SYNTAX_ERR;
 }
 
@@ -6956,7 +6956,7 @@ static char *expand_string_to_string(const char *str, int EXP_flags, int do_unba
 	} else {
 		if (HUSH_DEBUG)
 			if (list[1])
-				bb_error_msg_and_die("BUG in varexp2");
+				bb_simple_error_msg_and_die("BUG in varexp2");
 		/* actually, just move string 2*sizeof(char*) bytes back */
 		overlapping_strcpy((char*)list, list[0]);
 		if (do_unbackslash)
@@ -7217,7 +7217,7 @@ static void re_execute_shell(char ***to_free, const char *s,
 	if (argv[0][0] == '/')
 		execve(argv[0], argv, pp);
 	xfunc_error_retval = 127;
-	bb_error_msg_and_die("can't re-execute the shell");
+	bb_simple_error_msg_and_die("can't re-execute the shell");
 }
 #endif  /* !BB_MMU */
 
@@ -7919,7 +7919,7 @@ static void leave_var_nest_level(void)
 	G.var_nest_level--;
 	debug_printf_env("var_nest_level-- %u\n", G.var_nest_level);
 	if (HUSH_DEBUG && (int)G.var_nest_level < 0)
-		bb_error_msg_and_die("BUG: nesting underflow");
+		bb_simple_error_msg_and_die("BUG: nesting underflow");
 
 	remove_nested_vars();
 }
@@ -8776,7 +8776,7 @@ static int checkjobs(struct pipe *fg_pipe, pid_t waitfor_pid)
 		childpid = waitpid(-1, &status, attributes);
 		if (childpid <= 0) {
 			if (childpid && errno != ECHILD)
-				bb_perror_msg("waitpid");
+				bb_simple_perror_msg("waitpid");
 #if ENABLE_HUSH_FAST
 			else { /* Until next SIGCHLD, waitpid's are useless */
 				G.we_have_children = (childpid == 0);
@@ -9308,7 +9308,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
 		argv_expanded = NULL;
 		if (command->pid < 0) { /* [v]fork failed */
 			/* Clearly indicate, was it fork or vfork */
-			bb_perror_msg(BB_MMU ? "vfork"+1 : "vfork");
+			bb_simple_perror_msg(BB_MMU ? "vfork"+1 : "vfork");
 		} else {
 			pi->alive_cmds++;
 #if ENABLE_HUSH_JOB
@@ -10617,7 +10617,7 @@ static int FAST_FUNC builtin_read(char **argv)
 	}
 
 	if ((uintptr_t)r > 1) {
-		bb_error_msg("%s", r);
+		bb_simple_error_msg(r);
 		r = (char*)(uintptr_t)1;
 	}
 
@@ -10862,7 +10862,7 @@ static int FAST_FUNC builtin_unset(char **argv)
 	if (opts == (unsigned)-1)
 		return EXIT_FAILURE;
 	if (opts == 3) {
-		bb_error_msg("unset: -v and -f are exclusive");
+		bb_simple_error_msg("unset: -v and -f are exclusive");
 		return EXIT_FAILURE;
 	}
 	argv += optind;
@@ -11025,7 +11025,7 @@ Test that VAR is a valid variable name?
 
 	optstring = *++argv;
 	if (!optstring || !(var = *++argv)) {
-		bb_error_msg("usage: getopts OPTSTRING VAR [ARGS]");
+		bb_simple_error_msg("usage: getopts OPTSTRING VAR [ARGS]");
 		return EXIT_FAILURE;
 	}
 
@@ -11254,7 +11254,7 @@ static int FAST_FUNC builtin_trap(char **argv)
 	}
 
 	if (!argv[1]) { /* no second arg */
-		bb_error_msg("trap: invalid arguments");
+		bb_simple_error_msg("trap: invalid arguments");
 		return EXIT_FAILURE;
 	}
 
@@ -11295,7 +11295,7 @@ static struct pipe *parse_jobspec(const char *str)
 		/* It is "%%", "%+" or "%" - current job */
 		jobnum = G.last_jobid;
 		if (jobnum == 0) {
-			bb_error_msg("no current job");
+			bb_simple_error_msg("no current job");
 			return NULL;
 		}
 	}
@@ -11372,7 +11372,7 @@ static int FAST_FUNC builtin_fg_bg(char **argv)
 			delete_finished_job(pi);
 			return EXIT_SUCCESS;
 		}
-		bb_perror_msg("kill (SIGCONT)");
+		bb_simple_perror_msg("kill (SIGCONT)");
 	}
 
 	if (argv[0][0] == 'f') {
diff --git a/shell/shell_common.c b/shell/shell_common.c
index e0582ad..a935339 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -619,7 +619,7 @@ shell_builtin_ulimit(char **argv)
 				limit.rlim_cur = val;
 //bb_error_msg("setrlimit(%d, %lld, %lld)", limits_tbl[i].cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
 			if (setrlimit(limits_tbl[i].cmd, &limit) < 0) {
-				bb_perror_msg("error setting limit");
+				bb_simple_perror_msg("error setting limit");
 				return EXIT_FAILURE;
 			}
 		}