pipeln

commit 8afeed1a607f70606a81ab39cac8d684964fdab1
parent 29f6aee4d9c8df7375b369ddba9121f1cb4498bf
Author: Louis Burda <quent.burda@gmail.com>
Date:   Sat, 29 Jul 2023 00:35:43 +0200

Rename main.c to pipeln.c and properly close fds

Diffstat:
M
Makefile
 | 
6
+++---
M
build.jst.tmpl
 | 
3
++-
D
main.c
 | 
151
------------------------------------------------------------------------------
A
pipeln.c
 | 
154
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

4 files changed, 159 insertions(+), 155 deletions(-)
diff --git a/Makefile b/Makefile
@@ -3,11 +3,9 @@ BINDIR ?= /bin
 
 CFLAGS = -std=c99 -Wunused-variable -Wunused-function -Wconversion -O2
 
-
 all: pipeln
 
-pipeln: main.c
-	$(CC) -o $@ $^ $(CFLAGS)
+pipeln: pipeln.c
 
 clean:
 	rm -f pipeln
@@ -17,3 +15,5 @@ install:
 
 uninstall:
 	rm -f "$(DESTDIR)$(PREFIX)$(BINDIR)/pipeln"
+
+.PHONY: all clean install uninstall
diff --git a/build.jst.tmpl b/build.jst.tmpl
@@ -19,7 +19,7 @@ rule cc
 	#{CC} -o $out $in $cflags
 
 target pipeln
-	cc main.c
+	cc pipeln.c
 
 command install
 	install -m755 pipeln -t "#{DESTDIR}#{PREFIX}#{BINDIR}"
@@ -32,3 +32,4 @@ command clean
 
 command all
 	just pipeln
+
diff --git a/main.c b/main.c
@@ -1,151 +0,0 @@
-#include <asm-generic/errno-base.h>
-#include <linux/limits.h>
-#include <sys/wait.h>
-#include <errno.h>
-#include <unistd.h>
-#include <dirent.h>
-#include <wait.h>
-#include <stdio.h>
-#include <limits.h>
-#include <stdarg.h>
-#include <string.h>
-#include <stdlib.h>
-
-void __attribute__((noreturn))
-die(const char *fmt, ...)
-{
-	va_list ap;
-
-	fputs("pipeln: ", stderr);
-	va_start(ap, fmt);
-	vfprintf(stderr, fmt, ap);
-	va_end(ap);
-	if (*fmt && fmt[strlen(fmt)-1] == ':') {
-		fputc(' ', stderr);
-		perror(NULL);
-	} else {
-		fputc('\n', stderr);
-	}
-
-	exit(1);
-}
-
-char *
-findbin(const char *name)
-{
-	static char pathbuf[PATH_MAX];
-	const char *tok, *sep, *end;
-	struct dirent *ent;
-	size_t entlen;
-	DIR *dir;
-
-	tok = getenv("PATH");
-	while (tok) {
-		sep = strchr(tok, ':');
-		end = sep ? sep : tok + strlen(tok);
-		entlen = (size_t) (end - tok);
-		if (entlen > 0 && entlen < PATH_MAX) {
-			strncpy(pathbuf, tok, entlen);
-			pathbuf[entlen] = '\0';
-			dir = opendir(pathbuf);
-			if (dir) {
-				while ((ent = readdir(dir))) {
-					if (entlen + 1 + strlen(name) >= PATH_MAX)
-						continue;
-					if (!strcmp(ent->d_name, name)) {
-						strcat(pathbuf, "/");
-						strcat(pathbuf, name);
-						closedir(dir);
-						return pathbuf;
-					}
-				}
-				closedir(dir);
-			}
-		}
-		tok = sep ? sep + 1 : NULL;
-	}
-
-	die("findbin %s", name);
-}
-
-void
-run(int *in, int *out, const char **argv)
-{
-	pid_t child;
-
-	if (!argv[0]) die("run: empty command");
-
-	if (strncmp(argv[0], "/", 1) && strncmp(argv[0], "./", 2))
-		argv[0] = findbin(argv[0]);
-
-	child = fork();
-	if (child < 0) die("fork:");
-
-	if (!child) {
-		if (in) {
-			close(0);
-			if (dup2(in[0], 0) < 0)
-				die("dup2:");
-		}
-		if (out) {
-			close(1);
-			if (dup2(out[1], 1) < 0)
-				die("dup2:");
-		}
-		execv(argv[0], (char *const *) argv);
-		die("execv %s:", argv[0]);
-	}
-	if (in) close(in[0]);
-	if (out) close(out[1]);
-}
-
-void
-waitall(void)
-{
-	int rc, status, exitcode;
-
-	errno = 0;
-	exitcode = 0;
-	do {
-		rc = waitpid(-1, &status, 0);
-		if (rc < 0 && errno != EINTR && errno != ECHILD)
-			die("waitpid:");
-		if (!exitcode && WIFEXITED(status))
-			exitcode = WEXITSTATUS(status);
-		else if (!exitcode && WIFSIGNALED(status))
-			exitcode = 128 + WTERMSIG(status);
-	} while (rc >= 0 && errno != ECHILD);
-
-	exit(exitcode);
-}
-
-int
-main(int argc, const char **argv)
-{
-	const char **arg, **cmdargs;
-	int pipe1[2], pipe2[2];
-	int *in, *out;
-
-	/* first cmd from stdin */
-	in = NULL;
-	out = pipe2;
-
-	cmdargs = argv + 1;
-	for (arg = argv + 1; ; arg++) {
-		if (!*arg || !strcmp(*arg, "|")) {
-			/* last cmd goes to stdout */
-			if (!*arg) out = NULL;
-			else if (pipe(out)) die("pipe:");
-
-			/* run piped cmd */
-			*arg = NULL;
-			run(in, out, cmdargs);
-			if (!out) waitall();
-			cmdargs = arg + 1;
-
-			/* out => in */
-			in = out;
-			out = out == pipe1 ? pipe2 : pipe1;
-		}
-	}
-}
diff --git a/pipeln.c b/pipeln.c
@@ -0,0 +1,154 @@
+#include <asm-generic/errno-base.h>
+#include <linux/limits.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <wait.h>
+#include <stdio.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdlib.h>
+
+void __attribute__((noreturn))
+die(const char *fmt, ...)
+{
+	va_list ap;
+
+	fputs("pipeln: ", stderr);
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	if (*fmt && fmt[strlen(fmt)-1] == ':') {
+		fputc(' ', stderr);
+		perror(NULL);
+	} else {
+		fputc('\n', stderr);
+	}
+
+	exit(1);
+}
+
+char *
+findbin(const char *name)
+{
+	static char pathbuf[PATH_MAX];
+	const char *tok, *sep, *end;
+	struct dirent *ent;
+	size_t entlen;
+	DIR *dir;
+
+	tok = getenv("PATH");
+	while (tok) {
+		sep = strchr(tok, ':');
+		end = sep ? sep : tok + strlen(tok);
+		entlen = (size_t) (end - tok);
+		if (entlen > 0 && entlen < PATH_MAX) {
+			strncpy(pathbuf, tok, entlen);
+			pathbuf[entlen] = '\0';
+			dir = opendir(pathbuf);
+			if (dir) {
+				while ((ent = readdir(dir))) {
+					if (entlen + 1 + strlen(name) >= PATH_MAX)
+						continue;
+					if (!strcmp(ent->d_name, name)) {
+						strcat(pathbuf, "/");
+						strcat(pathbuf, name);
+						closedir(dir);
+						return pathbuf;
+					}
+				}
+				closedir(dir);
+			}
+		}
+		tok = sep ? sep + 1 : NULL;
+	}
+
+	die("findbin %s", name);
+}
+
+void
+run(int *in, int *out, const char **argv)
+{
+	pid_t child;
+
+	if (!argv[0]) die("run: empty command");
+
+	if (strncmp(argv[0], "/", 1) && strncmp(argv[0], "./", 2))
+		argv[0] = findbin(argv[0]);
+
+	child = fork();
+	if (child < 0) die("fork:");
+
+	if (!child) {
+		if (in) {
+			if (dup2(in[0], 0) < 0)
+				die("dup2:");
+			close(in[0]);
+			close(in[1]);
+		}
+		if (out) {
+			if (dup2(out[1], 1) < 0)
+				die("dup2:");
+			close(out[0]);
+			close(out[1]);
+		}
+		execv(argv[0], (char *const *) argv);
+		die("execv %s:", argv[0]);
+	}
+
+	if (in) close(in[0]);
+	if (out) close(out[1]);
+}
+
+void
+waitall(void)
+{
+	int rc, status, exitcode;
+
+	errno = 0;
+	exitcode = 0;
+	do {
+		rc = waitpid(-1, &status, 0);
+		if (rc < 0 && errno != EINTR && errno != ECHILD)
+			die("waitpid:");
+		if (!exitcode && WIFEXITED(status))
+			exitcode = WEXITSTATUS(status);
+		else if (!exitcode && WIFSIGNALED(status))
+			exitcode = 128 + WTERMSIG(status);
+	} while (rc >= 0 && errno != ECHILD);
+
+	exit(exitcode);
+}
+
+int
+main(int argc, const char **argv)
+{
+	const char **arg, **cmdargs;
+	int pipe1[2], pipe2[2];
+	int *in, *out;
+
+	/* first cmd from stdin */
+	in = NULL;
+	out = pipe2;
+
+	cmdargs = argv + 1;
+	for (arg = argv + 1; ; arg++) {
+		if (!*arg || !strcmp(*arg, "|")) {
+			/* last cmd goes to stdout */
+			if (!*arg) out = NULL;
+			else if (pipe(out)) die("pipe:");
+
+			/* run piped cmd */
+			*arg = NULL;
+			run(in, out, cmdargs);
+			if (!out) waitall();
+			cmdargs = arg + 1;
+
+			/* out => in */
+			in = out;
+			out = out == pipe1 ? pipe2 : pipe1;
+		}
+	}
+}