From e4c74e9d1c97feccb0c5337baceab4fc4aec592c Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Mon, 24 Jan 2022 21:17:08 +0100
Subject: Merged two random sources into this repository

---
 .gitignore  |  3 +++
 Makefile    | 10 ++++++++++
 cat.c       | 41 +++++++++++++++++++++++++++++++++++++++++
 fallocate.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 panic.c     | 14 ++++++++++++++
 panic.h     |  6 ++++++
 6 files changed, 133 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 cat.c
 create mode 100644 fallocate.c
 create mode 100644 panic.c
 create mode 100644 panic.h

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7b0dc11
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+cat
+fallocate
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..2027646
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,10 @@
+CFLAGS+=-std=c11 -Wall -Wextra -Wpedantic -D_POSIX_C_SOURCE=200809L
+
+all: cat fallocate
+
+cat: cat.o panic.o
+
+clean:
+	rm -f *.o cat fallocate
+
+.PHONY: all clean
diff --git a/cat.c b/cat.c
new file mode 100644
index 0000000..6f8ea55
--- /dev/null
+++ b/cat.c
@@ -0,0 +1,41 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "panic.h"
+
+
+void cat(int fd, char * name)
+{
+	char buffer[4096];
+	size_t length;
+	while (0 < (length=read(fd, buffer, sizeof(buffer))))
+		if (length != write(1, buffer, length))
+			panic("write: %s: %s", name, strerror(errno));
+	if (0 > length)
+		panic("read: %s: %s", name, strerror(errno));
+}
+
+
+int main(int argc, char * argv[])
+{
+	int i;
+	int fd;
+	if (1 == argc)
+		cat(0, "<stdin>");
+	else for (i = 1; i < argc; ++i)
+	{
+		fd = open(argv[i], O_RDONLY);
+		if (0 > fd)
+			panic("open: %s: %s", argv[i], strerror(errno));
+		else
+		{
+			cat(fd, argv[i]);
+			close(fd);
+		}
+	}
+}
diff --git a/fallocate.c b/fallocate.c
new file mode 100644
index 0000000..910d191
--- /dev/null
+++ b/fallocate.c
@@ -0,0 +1,59 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+#define EXIT_BAD_OPTION 2
+
+
+void usage(int fd, char * progname)
+{
+	dprintf(fd, "Usage: %s [-o offset] -l length name\n", progname);
+}
+
+
+int try_fallocate(char * filename, int offset, int length)
+{
+	int fd = open(filename, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+	if (-1 == fd) return -1;
+	int res = posix_fallocate(fd, offset, length);
+	if (-1 == res) return -1;
+	res = close(fd);
+	if (-1 == res) return -1;
+	return 0;
+}
+
+
+int main(int argc, char * argv[])
+{
+	int opt;
+	int offset = 0;
+	int length = 0;
+	char * filename;
+	while (-1 != (opt = getopt(argc, argv, "o:l:"))) {
+		switch (opt) {
+		case 'o':
+			offset = atoi(optarg);
+			break;
+		case 'l':
+			length = atoi(optarg);
+			break;
+		default:
+			usage(2, argv[0]);
+			exit(EXIT_BAD_OPTION);
+		}
+	}
+	if (0 >= length || argc <= optind) {
+		usage(2, argv[0]);
+		exit(EXIT_BAD_OPTION);
+	}
+	filename = argv[optind];
+	int res = try_fallocate(filename, offset, length);
+	if (-1 == res) {
+		dprintf(2, "%s: %s: %s\n", argv[0], filename, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+}
diff --git a/panic.c b/panic.c
new file mode 100644
index 0000000..ef4475e
--- /dev/null
+++ b/panic.c
@@ -0,0 +1,14 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdnoreturn.h>
+
+
+noreturn void panic(char * fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	vdprintf(2, fmt, args);
+	va_end(args);
+	exit(1);
+}
diff --git a/panic.h b/panic.h
new file mode 100644
index 0000000..dd0d1a8
--- /dev/null
+++ b/panic.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include <stdnoreturn.h>
+
+
+noreturn void panic(char * fmt, ...);
-- 
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