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, 21 insertions, 23 deletions

diff --git a/libbb/xfuncs_printf.c b/libbb/xfuncs_printf.c
index 6cc60f6c0..93f325c62 100644
--- a/libbb/xfuncs_printf.c
+++ b/libbb/xfuncs_printf.c
@@ -27,7 +27,7 @@
 
 void FAST_FUNC bb_die_memory_exhausted(void)
 {
-	bb_error_msg_and_die(bb_msg_memory_exhausted);
+	bb_simple_error_msg_and_die(bb_msg_memory_exhausted);
 }
 
 #ifndef DMALLOC
@@ -40,7 +40,7 @@ void* FAST_FUNC malloc_or_warn(size_t size)
 {
 	void *ptr = malloc(size);
 	if (ptr == NULL && size != 0)
-		bb_error_msg(bb_msg_memory_exhausted);
+		bb_simple_error_msg(bb_msg_memory_exhausted);
 	return ptr;
 }
 
@@ -97,7 +97,7 @@ char* FAST_FUNC xstrndup(const char *s, int n)
 	char *t;
 
 	if (ENABLE_DEBUG && s == NULL)
-		bb_error_msg_and_die("xstrndup bug");
+		bb_simple_error_msg_and_die("xstrndup bug");
 
 	/* We can just xmalloc(n+1) and strncpy into it, */
 	/* but think about xstrndup("abc", 10000) wastage! */
@@ -215,13 +215,13 @@ int FAST_FUNC rename_or_warn(const char *oldpath, const char *newpath)
 void FAST_FUNC xpipe(int filedes[2])
 {
 	if (pipe(filedes))
-		bb_perror_msg_and_die("can't create pipe");
+		bb_simple_perror_msg_and_die("can't create pipe");
 }
 
 void FAST_FUNC xdup2(int from, int to)
 {
 	if (dup2(from, to) != to)
-		bb_perror_msg_and_die("can't duplicate file descriptor");
+		bb_simple_perror_msg_and_die("can't duplicate file descriptor");
 		//		" %d to %d", from, to);
 }
 
@@ -245,7 +245,7 @@ void FAST_FUNC xwrite(int fd, const void *buf, size_t count)
 			 * or some writes succeeded, then we hit an error.
 			 * In either case, errno is set.
 			 */
-			bb_perror_msg_and_die(
+			bb_simple_perror_msg_and_die(
 				size >= 0 ? "short write" : "write error"
 			);
 		}
@@ -259,7 +259,7 @@ void FAST_FUNC xwrite_str(int fd, const char *str)
 void FAST_FUNC xclose(int fd)
 {
 	if (close(fd))
-		bb_perror_msg_and_die("close failed");
+		bb_simple_perror_msg_and_die("close failed");
 }
 
 // Die with an error message if we can't lseek to the right spot.
@@ -267,9 +267,7 @@ off_t FAST_FUNC xlseek(int fd, off_t offset, int whence)
 {
 	off_t off = lseek(fd, offset, whence);
 	if (off == (off_t)-1) {
-		if (whence == SEEK_SET)
-			bb_perror_msg_and_die("lseek(%"OFF_FMT"u)", offset);
-		bb_perror_msg_and_die("lseek");
+		bb_perror_msg_and_die("lseek(%"OFF_FMT"u, %d)", offset, whence);
 	}
 	return off;
 }
@@ -384,23 +382,23 @@ void FAST_FUNC bb_unsetenv_and_free(char *var)
 // setgid() will fail and we'll _still_be_root_, which is bad.)
 void FAST_FUNC xsetgid(gid_t gid)
 {
-	if (setgid(gid)) bb_perror_msg_and_die("setgid");
+	if (setgid(gid)) bb_simple_perror_msg_and_die("setgid");
 }
 
 // Die with an error message if we can't set uid.  (See xsetgid() for why.)
 void FAST_FUNC xsetuid(uid_t uid)
 {
-	if (setuid(uid)) bb_perror_msg_and_die("setuid");
+	if (setuid(uid)) bb_simple_perror_msg_and_die("setuid");
 }
 
 void FAST_FUNC xsetegid(gid_t egid)
 {
-	if (setegid(egid)) bb_perror_msg_and_die("setegid");
+	if (setegid(egid)) bb_simple_perror_msg_and_die("setegid");
 }
 
 void FAST_FUNC xseteuid(uid_t euid)
 {
-	if (seteuid(euid)) bb_perror_msg_and_die("seteuid");
+	if (seteuid(euid)) bb_simple_perror_msg_and_die("seteuid");
 }
 
 // Die if we can't chdir to a new path.
@@ -413,7 +411,7 @@ void FAST_FUNC xchdir(const char *path)
 void FAST_FUNC xfchdir(int fd)
 {
 	if (fchdir(fd))
-		bb_perror_msg_and_die("fchdir");
+		bb_simple_perror_msg_and_die("fchdir");
 }
 
 void FAST_FUNC xchroot(const char *path)
@@ -463,7 +461,7 @@ int FAST_FUNC xsocket(int domain, int type, int protocol)
 IF_FEATURE_IPV6(if (domain == AF_INET6) s = "INET6";)
 		bb_perror_msg_and_die("socket(AF_%s,%d,%d)", s, type, protocol);
 #else
-		bb_perror_msg_and_die("socket");
+		bb_simple_perror_msg_and_die("socket");
 #endif
 	}
 
@@ -473,13 +471,13 @@ IF_FEATURE_IPV6(if (domain == AF_INET6) s = "INET6";)
 // Die with an error message if we can't bind a socket to an address.
 void FAST_FUNC xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
 {
-	if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
+	if (bind(sockfd, my_addr, addrlen)) bb_simple_perror_msg_and_die("bind");
 }
 
 // Die with an error message if we can't listen for connections on a socket.
 void FAST_FUNC xlisten(int s, int backlog)
 {
-	if (listen(s, backlog)) bb_perror_msg_and_die("listen");
+	if (listen(s, backlog)) bb_simple_perror_msg_and_die("listen");
 }
 
 /* Die with an error message if sendto failed.
@@ -491,7 +489,7 @@ ssize_t FAST_FUNC xsendto(int s, const void *buf, size_t len, const struct socka
 	if (ret < 0) {
 		if (ENABLE_FEATURE_CLEAN_UP)
 			close(s);
-		bb_perror_msg_and_die("sendto");
+		bb_simple_perror_msg_and_die("sendto");
 	}
 	return ret;
 }
@@ -519,12 +517,12 @@ void FAST_FUNC selinux_or_die(void)
 #if ENABLE_SELINUX
 	int rc = is_selinux_enabled();
 	if (rc == 0) {
-		bb_error_msg_and_die("SELinux is disabled");
+		bb_simple_error_msg_and_die("SELinux is disabled");
 	} else if (rc < 0) {
-		bb_error_msg_and_die("is_selinux_enabled() failed");
+		bb_simple_error_msg_and_die("is_selinux_enabled() failed");
 	}
 #else
-	bb_error_msg_and_die("SELinux support is disabled");
+	bb_simple_error_msg_and_die("SELinux support is disabled");
 #endif
 }
 
@@ -675,7 +673,7 @@ pid_t FAST_FUNC xfork(void)
 	pid_t pid;
 	pid = fork();
 	if (pid < 0) /* wtf? */
-		bb_perror_msg_and_die("vfork"+1);
+		bb_simple_perror_msg_and_die("vfork"+1);
 	return pid;
 }
 #endif