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>

1 files changed, 10 insertions, 10 deletions

diff --git a/networking/ntpd.c b/networking/ntpd.c
index d55b070..2700cf5 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -905,7 +905,7 @@ do_sendto(int fd,
 		ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
 	}
 	if (ret != len) {
-		bb_perror_msg("send failed");
+		bb_simple_perror_msg("send failed");
 		return -1;
 	}
 	return 0;
@@ -1121,7 +1121,7 @@ step_time(double offset)
 	dtime = tvc.tv_sec + (1.0e-6 * tvc.tv_usec) + offset;
 	d_to_tv(dtime, &tvn);
 	if (settimeofday(&tvn, NULL) == -1)
-		bb_perror_msg_and_die("settimeofday");
+		bb_simple_perror_msg_and_die("settimeofday");
 
 	VERB2 {
 		tval = tvc.tv_sec;
@@ -1494,7 +1494,7 @@ select_and_cluster(void)
 		/* Starting from 1 is ok here */
 		for (i = 1; i < num_survivors; i++) {
 			if (G.last_update_peer == survivor[i].p) {
-				VERB5 bb_error_msg("keeping old synced peer");
+				VERB5 bb_simple_error_msg("keeping old synced peer");
 				p = G.last_update_peer;
 				goto keep_old;
 			}
@@ -1702,7 +1702,7 @@ update_local_clock(peer_t *p)
 #else
 			set_new_values(STATE_SYNC, offset, recv_time);
 #endif
-			VERB4 bb_error_msg("transitioning to FREQ, datapoint ignored");
+			VERB4 bb_simple_error_msg("transitioning to FREQ, datapoint ignored");
 			return 0; /* "leave poll interval as is" */
 
 #if 0 /* this is dead code for now */
@@ -1796,7 +1796,7 @@ update_local_clock(peer_t *p)
 	VERB4 {
 		memset(&tmx, 0, sizeof(tmx));
 		if (adjtimex(&tmx) < 0)
-			bb_perror_msg_and_die("adjtimex");
+			bb_simple_perror_msg_and_die("adjtimex");
 		bb_error_msg("p adjtimex freq:%ld offset:%+ld status:0x%x tc:%ld",
 				tmx.freq, tmx.offset, tmx.status, tmx.constant);
 	}
@@ -1906,7 +1906,7 @@ update_local_clock(peer_t *p)
 	//tmx.maxerror = (uint32_t)((sys_rootdelay / 2 + sys_rootdisp) * 1e6);
 	rc = adjtimex(&tmx);
 	if (rc < 0)
-		bb_perror_msg_and_die("adjtimex");
+		bb_simple_perror_msg_and_die("adjtimex");
 	/* NB: here kernel returns constant == G.poll_exp, not == G.poll_exp - 4.
 	 * Not sure why. Perhaps it is normal.
 	 */
@@ -2248,7 +2248,7 @@ recv_and_process_client_pkt(void /*int fd*/)
 		if (size < 0) {
 			if (errno == EAGAIN)
 				goto bail;
-			bb_perror_msg_and_die("recv");
+			bb_simple_perror_msg_and_die("recv");
 		}
 		addr = xmalloc_sockaddr2dotted_noport(from);
 		bb_error_msg("malformed packet received from %s: size %u", addr, (int)size);
@@ -2415,7 +2415,7 @@ static NOINLINE void ntp_init(char **argv)
 	srand(getpid());
 
 	if (getuid())
-		bb_error_msg_and_die(bb_msg_you_must_be_root);
+		bb_simple_error_msg_and_die(bb_msg_you_must_be_root);
 
 	/* Set some globals */
 	G.discipline_jitter = G_precision_sec;
@@ -2491,7 +2491,7 @@ static NOINLINE void ntp_init(char **argv)
 				/* supports 'sha' and 'sha1' formats */
 				hash_type = HASH_SHA1;
 			else
-				bb_error_msg_and_die("only MD5 and SHA1 keys supported");
+				bb_simple_error_msg_and_die("only MD5 and SHA1 keys supported");
 /* man ntp.keys:
  *  MD5    The key is 1 to 16 printable characters terminated by an EOL,
  *         whitespace, or a # (which is the "start of comment" character).
@@ -2674,7 +2674,7 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
 				if (p->p_fd == -1) {
 					/* Time to send new req */
 					if (--cnt == 0) {
-						VERB4 bb_error_msg("disabling burst mode");
+						VERB4 bb_simple_error_msg("disabling burst mode");
 						G.polladj_count = 0;
 						G.poll_exp = MINPOLL;
 					}