commit 2636b3f2de18f146b676f74bdc1269ef7e2fa1c1
parent a3deb1b53a2cc67b0c53bb3391f32e166546782c
Author: Friedel Schön <[email protected]>
Date: Thu, 5 Sep 2024 23:06:00 +0200
add pipeto utility for simple piping
Diffstat:
| M | Makefile | 14 | +++++++++----- |
| A | pipeto.c | 130 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
2 files changed, 139 insertions(+), 5 deletions(-)
diff --git a/Makefile b/Makefile
@@ -2,19 +2,23 @@ CFLAGS += -g -std=c99 -O2 -Wall -Wextra -Wpedantic
LDFLAGS += -lncurses
PREFIX ?= /usr
+BINS := textselect pipeto
+HEADERS := arg.h config.h
+
.PHONY: all install clean
-all: textselect
+all: $(BINS)
-textselect.o: textselect.c arg.h config.h
+%.o: %.c $(HEADERS)
$(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<
-textselect: textselect.o
+%: %.o
$(CC) $< -o $@ $(LDFLAGS)
-install: textselect textselect.1
+install: all
cp textselect $(PREFIX)/bin/
+ cp pipeto $(PREFIX)/bin/
cp textselect.1 $(PREFIX)/share/man/man1/
clean:
- rm -f textselect textselect.o
+ rm -f textselect textselect.o pipeto pipeto.o
diff --git a/pipeto.c b/pipeto.c
@@ -0,0 +1,130 @@
+#include "arg.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define USAGE "Usage: %s [-h] [-d delimiter] <inputcmd> {delimiter} <outputcmd>\n"
+
+#define NORETURN __attribute__((noreturn))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+
+static char *argv0 = NULL;
+static const char *delimiter = "+";
+
+static void die(const char *message) {
+ fprintf(stderr, "error: %s: %s\n", message, strerror(errno));
+ exit(EXIT_FAILURE);
+}
+
+static void help(void) {
+ fprintf(stderr,
+ USAGE "Pipe output of command to another without a shell.\n"
+ "\n"
+ "Options:\n"
+ " -h Display this help message and exit\n"
+ " -d delimeter Split commands by demiliter (default: %s)\n"
+ "\n"
+ "Examples:\n"
+ " pipeto xbps-query -l + wc -l\n"
+ " pipeto find -name 'myfile' + xargs rm\n",
+ argv0, delimiter);
+}
+
+static void usage(int exitcode) {
+ fprintf(stderr, USAGE, argv0);
+ exit(exitcode);
+}
+
+static void runcommand(char **inputcmd, char **outputcmd) {
+ int pipefd[2]; // pipefd[0] is for reading, pipefd[1] is for writing
+ pid_t pid1, pid2;
+
+ if (pipe(pipefd) == -1) {
+ perror("pipe");
+ exit(EXIT_FAILURE);
+ }
+
+ // First child process to run inputcmd
+ if ((pid1 = fork()) < 0) {
+ perror("fork");
+ exit(EXIT_FAILURE);
+ }
+
+ if (pid1 == 0) {
+ // Child process 1: will exec inputcmd
+ close(pipefd[0]); // Close unused read end
+ dup2(pipefd[1], STDOUT_FILENO); // Redirect stdout to pipe write end
+ close(pipefd[1]); // Close write end after dup
+
+ execvp(inputcmd[0], inputcmd); // Replace child process with inputcmd
+ die("unable to execute input command");
+ }
+
+ // Second child process to run outputcmd
+ if ((pid2 = fork()) < 0) {
+ perror("fork");
+ exit(EXIT_FAILURE);
+ }
+
+ if (pid2 == 0) {
+ // Child process 2: will exec outputcmd
+ close(pipefd[1]); // Close unused write end
+ dup2(pipefd[0], STDIN_FILENO); // Redirect stdin to pipe read end
+ close(pipefd[0]); // Close read end after dup
+
+ execvp(outputcmd[0], outputcmd); // Replace child process with outputcmd
+ die("unable to execute output command");
+ }
+
+ // Parent process
+ close(pipefd[0]); // Close both ends of the pipe in the parent
+ close(pipefd[1]);
+
+ // Wait for both children to finish
+ waitpid(pid1, NULL, 0);
+ waitpid(pid2, NULL, 0);
+}
+
+int main(int argc, char *argv[]) {
+ argv0 = argv[0];
+ ARGBEGIN
+ switch (OPT) {
+ case 'h':
+ help();
+ exit(0);
+ case 'd':
+ delimiter = EARGF(usage(1));
+ break;
+ default:
+ fprintf(stderr, "error: unknown option '-%c'\n", OPT);
+ usage(1);
+ }
+ ARGEND;
+
+ if (argc == 0) {
+ fprintf(stderr, "error: missing command\n");
+ usage(1);
+ }
+
+ char **outputcmd = NULL;
+
+ for (int i = 0; i < argc; i++) {
+ if (!strcmp(argv[i], delimiter)) {
+ if (outputcmd) {
+ fprintf(stderr, "error: delimiter occured more than once\n");
+ exit(EXIT_FAILURE);
+ }
+ argv[i] = NULL;
+ outputcmd = &argv[i + 1];
+ }
+ }
+
+ runcommand(argv, outputcmd);
+
+ return 0;
+}
