*: more readable handling of pipe fds. No code changes.

12 files changed, 88 insertions, 82 deletions

diff --git a/archival/libunarchive/open_transformer.c b/archival/libunarchive/open_transformer.c
index d6f5e6271..3c551de06 100644
--- a/archival/libunarchive/open_transformer.c
+++ b/archival/libunarchive/open_transformer.c
@@ -15,10 +15,10 @@ int open_transformer(int src_fd,
 	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd),
 	const char *transform_prog)
 {
-	int fd_pipe[2];
+	struct fd_pair fd_pipe;
 	int pid;
 
-	xpipe(fd_pipe);
+	xpiped_pair(fd_pipe);
 
 #if BB_MMU
 	pid = fork();
@@ -30,12 +30,12 @@ int open_transformer(int src_fd,
 
 	if (pid == 0) {
 		/* child process */
-		close(fd_pipe[0]); /* We don't want to read from the parent */
+		close(fd_pipe.rd); /* We don't want to read from the parent */
 		// FIXME: error check?
 #if BB_MMU
-		transformer(src_fd, fd_pipe[1]);
+		transformer(src_fd, fd_pipe.wr);
 		if (ENABLE_FEATURE_CLEAN_UP) {
-			close(fd_pipe[1]); /* Send EOF */
+			close(fd_pipe.wr); /* Send EOF */
 			close(src_fd);
 		}
 		exit(0);
@@ -43,7 +43,7 @@ int open_transformer(int src_fd,
 		{
 			char *argv[4];
 			xmove_fd(src_fd, 0);
-			xmove_fd(fd_pipe[1], 1);
+			xmove_fd(fd_pipe.wr, 1);
 			argv[0] = (char*)transform_prog;
 			argv[1] = (char*)"-cf";
 			argv[2] = (char*)"-";
@@ -56,7 +56,7 @@ int open_transformer(int src_fd,
 	}
 
 	/* parent process */
-	close(fd_pipe[1]); /* Don't want to write to the child */
+	close(fd_pipe.wr); /* Don't want to write to the child */
 
-	return fd_pipe[0];
+	return fd_pipe.rd;
 }
diff --git a/archival/libunarchive/seek_by_jump.c b/archival/libunarchive/seek_by_jump.c
index edbf46b21..8b5f3e887 100644
--- a/archival/libunarchive/seek_by_jump.c
+++ b/archival/libunarchive/seek_by_jump.c
@@ -6,7 +6,7 @@
 #include "libbb.h"
 #include "unarchive.h"
 
-void seek_by_jump(const archive_handle_t *archive_handle, const unsigned int amount)
+void seek_by_jump(const archive_handle_t *archive_handle, unsigned amount)
 {
 	if (lseek(archive_handle->src_fd, (off_t) amount, SEEK_CUR) == (off_t) -1) {
 #if ENABLE_FEATURE_UNARCHIVE_TAPE
diff --git a/archival/libunarchive/seek_by_read.c b/archival/libunarchive/seek_by_read.c
index 452d82d10..1f2b80571 100644
--- a/archival/libunarchive/seek_by_read.c
+++ b/archival/libunarchive/seek_by_read.c
@@ -6,10 +6,10 @@
 #include "libbb.h"
 #include "unarchive.h"
 
-/*  If we are reading through a pipe(), or from stdin then we can't lseek,
+/*  If we are reading through a pipe, or from stdin then we can't lseek,
  *  we must read and discard the data to skip over it.
  */
-void seek_by_read(const archive_handle_t *archive_handle, const unsigned int jump_size)
+void seek_by_read(const archive_handle_t *archive_handle, unsigned jump_size)
 {
 	if (jump_size)
 		bb_copyfd_exact_size(archive_handle->src_fd, -1, jump_size);
diff --git a/archival/tar.c b/archival/tar.c
index a8ff7b894..4ec454b88 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -521,14 +521,14 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
 
 		volatile int vfork_exec_errno = 0;
 #if WAIT_FOR_CHILD
-		struct { int rd; int wr; } gzipStatusPipe;
+		struct fd_pair gzipStatusPipe;
 #endif
-		struct { int rd; int wr; } gzipDataPipe;
+		struct fd_pair gzipDataPipe;
 		const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
 
-		xpipe(&gzipDataPipe.rd);
+		xpiped_pair(gzipDataPipe);
 #if WAIT_FOR_CHILD
-		xpipe(&gzipStatusPipe.rd);
+		xpiped_pair(gzipStatusPipe);
 #endif
 
 		signal(SIGPIPE, SIG_IGN); /* we only want EPIPE on errors */
diff --git a/include/libbb.h b/include/libbb.h
index 3175c8e7f..f505cc718 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -294,10 +294,15 @@ int xopen(const char *pathname, int flags);
 int xopen3(const char *pathname, int flags, int mode);
 int open_or_warn(const char *pathname, int flags);
 int open3_or_warn(const char *pathname, int flags, int mode);
-void xpipe(int filedes[2]);
 off_t xlseek(int fd, off_t offset, int whence);
 off_t fdlength(int fd);
 
+void xpipe(int filedes[2]);
+/* In this form code with pipes is much more readable */
+struct fd_pair { int rd; int wr; };
+#define piped_pair(pair)  pipe(&((pair).rd))
+#define xpiped_pair(pair) xpipe(&((pair).rd))
+
 /* Useful for having small structure members/global variables */
 typedef int8_t socktype_t;
 typedef int8_t family_t;
diff --git a/include/unarchive.h b/include/unarchive.h
index 8b76217b4..bfd6488db 100644
--- a/include/unarchive.h
+++ b/include/unarchive.h
@@ -92,8 +92,8 @@ extern char get_header_tar_bz2(archive_handle_t *archive_handle);
 extern char get_header_tar_lzma(archive_handle_t *archive_handle);
 extern char get_header_tar_gz(archive_handle_t *archive_handle);
 
-extern void seek_by_jump(const archive_handle_t *archive_handle, const unsigned amount);
-extern void seek_by_read(const archive_handle_t *archive_handle, const unsigned amount);
+extern void seek_by_jump(const archive_handle_t *archive_handle, unsigned amount);
+extern void seek_by_read(const archive_handle_t *archive_handle, unsigned amount);
 
 extern ssize_t archive_xread_all_eof(archive_handle_t *archive_handle, unsigned char *buf, size_t count);
 
diff --git a/miscutils/crontab.c b/miscutils/crontab.c
index 71037b7ee..b292535b1 100644
--- a/miscutils/crontab.c
+++ b/miscutils/crontab.c
@@ -70,18 +70,18 @@ static void edit_file(const struct passwd *pas, const char *file)
 
 static int open_as_user(const struct passwd *pas, const char *file)
 {
-	int filedes[2];
+	struct fd_pair filedes;
 	pid_t pid;
 	char c;
 
-	xpipe(filedes);
+	xpiped_pair(filedes);
 	pid = vfork();
 	if (pid < 0) /* ERROR */
 		bb_perror_msg_and_die("vfork");
 	if (pid) { /* PARENT */
-		int n = safe_read(filedes[0], &c, 1);
-		close(filedes[0]);
-		close(filedes[1]);
+		int n = safe_read(filedes.rd, &c, 1);
+		close(filedes.rd);
+		close(filedes.wr);
 		if (n > 0) /* child says it can read */
 			return open(file, O_RDONLY);
 		return -1;
@@ -95,7 +95,7 @@ static int open_as_user(const struct passwd *pas, const char *file)
 	/* We just try to read one byte. If that works, file is readable
 	 * under this user. We signal that by sending one byte to parent. */
 	if (safe_read(xopen(file, O_RDONLY), &c, 1) == 1)
-		safe_write(filedes[1], &c, 1); /* "papa, I can read!" */
+		safe_write(filedes.wr, &c, 1); /* "papa, I can read!" */
 	_exit(0);
 }
 
diff --git a/networking/httpd.c b/networking/httpd.c
index 1ac49e7a2..2c580b032 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -1305,8 +1305,8 @@ static void send_cgi_and_exit(
 		const char *cookie,
 		const char *content_type)
 {
-	struct { int rd; int wr; } fromCgi;  /* CGI -> httpd pipe */
-	struct { int rd; int wr; } toCgi;    /* httpd -> CGI pipe */
+	struct fd_pair fromCgi;  /* CGI -> httpd pipe */
+	struct fd_pair toCgi;    /* httpd -> CGI pipe */
 	char *fullpath;
 	char *script;
 	char *purl;
@@ -1396,8 +1396,8 @@ static void send_cgi_and_exit(
 	if (referer)
 		setenv1("HTTP_REFERER", referer);
 
-	xpipe(&fromCgi.rd);
-	xpipe(&toCgi.rd);
+	xpiped_pair(fromCgi);
+	xpiped_pair(toCgi);
 
 	pid = vfork();
 	if (pid < 0) {
diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index d0d7bfe5b..58e69530c 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -987,11 +987,11 @@ static int iface_down(struct interface_defn_t *iface)
 static int popen2(FILE **in, FILE **out, char *command, char *param)
 {
 	char *argv[3] = { command, param, NULL };
-	int infd[2], outfd[2];
+	struct fd_pair infd, outfd;
 	pid_t pid;
 
-	xpipe(infd);
-	xpipe(outfd);
+	xpiped_pair(infd);
+	xpiped_pair(outfd);
 
 	fflush(NULL);
 	pid = fork();
@@ -1001,18 +1001,18 @@ static int popen2(FILE **in, FILE **out, char *command, char *param)
 		bb_perror_msg_and_die("fork");
 	case 0:  /* child */
 		/* NB: close _first_, then move fds! */
-		close(infd[1]);
-		close(outfd[0]);
-		xmove_fd(infd[0], 0);
-		xmove_fd(outfd[1], 1);
+		close(infd.wr);
+		close(outfd.rd);
+		xmove_fd(infd.rd, 0);
+		xmove_fd(outfd.wr, 1);
 		BB_EXECVP(command, argv);
 		_exit(127);
 	}
 	/* parent */
-	close(infd[0]);
-	close(outfd[1]);
-	*in = fdopen(infd[1], "w");
-	*out = fdopen(outfd[0], "r");
+	close(infd.rd);
+	close(outfd.wr);
+	*in = fdopen(infd.wr, "w");
+	*out = fdopen(outfd.rd, "r");
 	return pid;
 }
 
diff --git a/networking/udhcp/signalpipe.c b/networking/udhcp/signalpipe.c
index 845aa3a9a..918abd02d 100644
--- a/networking/udhcp/signalpipe.c
+++ b/networking/udhcp/signalpipe.c
@@ -23,12 +23,12 @@
 #include "common.h"
 
 
-static int signal_pipe[2];
+static struct fd_pair signal_pipe;
 
 static void signal_handler(int sig)
 {
 	unsigned char ch = sig; /* use char, avoid dealing with partial writes */
-	if (write(signal_pipe[1], &ch, 1) != 1)
+	if (write(signal_pipe.wr, &ch, 1) != 1)
 		bb_perror_msg("cannot send signal");
 }
 
@@ -38,10 +38,10 @@ static void signal_handler(int sig)
 void udhcp_sp_setup(void)
 {
 	/* was socketpair, but it needs AF_UNIX in kernel */
-	xpipe(signal_pipe);
-	close_on_exec_on(signal_pipe[0]);
-	close_on_exec_on(signal_pipe[1]);
-	ndelay_on(signal_pipe[1]);
+	xpiped_pair(signal_pipe);
+	close_on_exec_on(signal_pipe.rd);
+	close_on_exec_on(signal_pipe.wr);
+	ndelay_on(signal_pipe.wr);
 	signal(SIGUSR1, signal_handler);
 	signal(SIGUSR2, signal_handler);
 	signal(SIGTERM, signal_handler);
@@ -54,12 +54,12 @@ void udhcp_sp_setup(void)
 int udhcp_sp_fd_set(fd_set *rfds, int extra_fd)
 {
 	FD_ZERO(rfds);
-	FD_SET(signal_pipe[0], rfds);
+	FD_SET(signal_pipe.rd, rfds);
 	if (extra_fd >= 0) {
 		close_on_exec_on(extra_fd);
 		FD_SET(extra_fd, rfds);
 	}
-	return signal_pipe[0] > extra_fd ? signal_pipe[0] : extra_fd;
+	return signal_pipe.rd > extra_fd ? signal_pipe.rd : extra_fd;
 }
 
 
@@ -70,10 +70,10 @@ int udhcp_sp_read(const fd_set *rfds)
 {
 	unsigned char sig;
 
-	if (!FD_ISSET(signal_pipe[0], rfds))
+	if (!FD_ISSET(signal_pipe.rd, rfds))
 		return 0;
 
-	if (read(signal_pipe[0], &sig, 1) != 1)
+	if (safe_read(signal_pipe.rd, &sig, 1) != 1)
 		return -1;
 
 	return sig;
diff --git a/runit/runsv.c b/runit/runsv.c
index e9a074580..e1d99e2df 100644
--- a/runit/runsv.c
+++ b/runit/runsv.c
@@ -90,8 +90,8 @@ struct globals {
 	smallint haslog;
 	smallint sigterm;
 	smallint pidchanged;
-	int selfpipe[2];
-	int logpipe[2];
+	struct fd_pair selfpipe;
+	struct fd_pair logpipe;
 	char *dir;
 	struct svdir svd[2];
 };
@@ -130,13 +130,13 @@ static void warn_cannot(const char *m)
 
 static void s_child(int sig_no)
 {
-	write(selfpipe[1], "", 1);
+	write(selfpipe.wr, "", 1);
 }
 
 static void s_term(int sig_no)
 {
 	sigterm = 1;
-	write(selfpipe[1], "", 1); /* XXX */
+	write(selfpipe.wr, "", 1); /* XXX */
 }
 
 static char *add_str(char *p, const char *to_add)
@@ -275,7 +275,7 @@ static unsigned custom(struct svdir *s, char c)
 				return 0;
 			}
 			if (!pid) {
-				if (haslog && dup2(logpipe[1], 1) == -1)
+				if (haslog && dup2(logpipe.wr, 1) == -1)
 					warn_cannot("setup stdout for control/?");
 				prog[0] = a;
 				prog[1] = NULL;
@@ -335,13 +335,14 @@ static void startservice(struct svdir *s)
 	if (p == 0) {
 		/* child */
 		if (haslog) {
+			/* NB: bug alert! right order is close, then dup2 */
 			if (s->islog) {
-				xdup2(logpipe[0], 0);
-				close(logpipe[1]);
 				xchdir("./log");
+				close(logpipe.wr);
+				xdup2(logpipe.rd, 0);
 			} else {
-				xdup2(logpipe[1], 1);
-				close(logpipe[0]);
+				close(logpipe.rd);
+				xdup2(logpipe.wr, 1);
 			}
 		}
 		signal(SIGCHLD, SIG_DFL);
@@ -452,11 +453,11 @@ int runsv_main(int argc, char **argv)
 		bb_show_usage();
 	dir = argv[1];
 
-	xpipe(selfpipe);
-	close_on_exec_on(selfpipe[0]);
-	close_on_exec_on(selfpipe[1]);
-	ndelay_on(selfpipe[0]);
-	ndelay_on(selfpipe[1]);
+	xpiped_pair(selfpipe);
+	close_on_exec_on(selfpipe.rd);
+	close_on_exec_on(selfpipe.wr);
+	ndelay_on(selfpipe.rd);
+	ndelay_on(selfpipe.wr);
 
 	sig_block(SIGCHLD);
 	sig_catch(SIGCHLD, s_child);
@@ -489,9 +490,9 @@ int runsv_main(int argc, char **argv)
 			gettimeofday_ns(&svd[1].start);
 			if (stat("log/down", &s) != -1)
 				svd[1].want = W_DOWN;
-			xpipe(logpipe);
-			close_on_exec_on(logpipe[0]);
-			close_on_exec_on(logpipe[1]);
+			xpiped_pair(logpipe);
+			close_on_exec_on(logpipe.rd);
+			close_on_exec_on(logpipe.wr);
 		}
 	}
 
@@ -572,7 +573,7 @@ int runsv_main(int argc, char **argv)
 			if (svd[0].want == W_UP || svd[0].state == S_FINISH)
 				startservice(&svd[0]);
 
-		x[0].fd = selfpipe[0];
+		x[0].fd = selfpipe.rd;
 		x[0].events = POLLIN;
 		x[1].fd = svd[0].fdcontrol;
 		x[1].events = POLLIN;
@@ -585,7 +586,7 @@ int runsv_main(int argc, char **argv)
 		sig_block(SIGTERM);
 		sig_block(SIGCHLD);
 
-		while (read(selfpipe[0], &ch, 1) == 1)
+		while (read(selfpipe.rd, &ch, 1) == 1)
 			continue;
 
 		for (;;) {
@@ -630,7 +631,7 @@ int runsv_main(int argc, char **argv)
 						sleep(1);
 				}
 			}
-		}
+		} /* for (;;) */
 		if (read(svd[0].fdcontrol, &ch, 1) == 1)
 			ctrl(&svd[0], ch);
 		if (haslog)
@@ -649,11 +650,11 @@ int runsv_main(int argc, char **argv)
 				svd[1].want = W_EXIT;
 				/* stopservice(&svd[1]); */
 				update_status(&svd[1]);
-				close(logpipe[1]);
-				close(logpipe[0]);
+				close(logpipe.wr);
+				close(logpipe.rd);
 			}
 		}
-	}
+	} /* for (;;) */
 	/* not reached */
 	return 0;
 }
diff --git a/runit/runsvdir.c b/runit/runsvdir.c
index 838490376..4225ac101 100644
--- a/runit/runsvdir.c
+++ b/runit/runsvdir.c
@@ -47,7 +47,7 @@ static char *svdir;
 static int svnum;
 static char *rplog;
 static int rploglen;
-static int logpipe[2];
+static struct fd_pair logpipe;
 static struct pollfd pfd[1];
 static unsigned stamplog;
 static smallint check = 1;
@@ -186,19 +186,19 @@ static int setup_log(void)
 		warnx("log must have at least seven characters");
 		return 0;
 	}
-	if (pipe(logpipe)) {
+	if (piped_pair(logpipe)) {
 		warnx("cannot create pipe for log");
 		return -1;
 	}
-	close_on_exec_on(logpipe[1]);
-	close_on_exec_on(logpipe[0]);
-	ndelay_on(logpipe[0]);
-	ndelay_on(logpipe[1]);
-	if (dup2(logpipe[1], 2) == -1) {
+	close_on_exec_on(logpipe.rd);
+	close_on_exec_on(logpipe.wr);
+	ndelay_on(logpipe.rd);
+	ndelay_on(logpipe.wr);
+	if (dup2(logpipe.wr, 2) == -1) {
 		warnx("cannot set filedescriptor for log");
 		return -1;
 	}
-	pfd[0].fd = logpipe[0];
+	pfd[0].fd = logpipe.rd;
 	pfd[0].events = POLLIN;
 	stamplog = monotonic_sec();
 	return 1;
@@ -296,7 +296,7 @@ int runsvdir_main(int argc, char **argv)
 
 		if (rplog) {
 			if ((int)(now - stamplog) >= 0) {
-				write(logpipe[1], ".", 1);
+				write(logpipe.wr, ".", 1);
 				stamplog = now + 900;
 			}
 		}
@@ -311,7 +311,7 @@ int runsvdir_main(int argc, char **argv)
 		sig_unblock(SIGCHLD);
 
 		if (pfd[0].revents & POLLIN) {
-			while (read(logpipe[0], &ch, 1) > 0) {
+			while (read(logpipe.rd, &ch, 1) > 0) {
 				if (ch) {
 					for (i = 6; i < rploglen; i++)
 						rplog[i-1] = rplog[i];