From: git <redacted>
Date: Sun, 24 May 2026 12:59:48 +0000 (-0400)
Subject: initial public commit
X-Git-Url: https://git.datadissipation.net/?a=commitdiff_plain;h=9486f5946765dc462feaab9cfe1c209dae1c11f3;p=free.git

initial public commit
---

9486f5946765dc462feaab9cfe1c209dae1c11f3
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..78e53b5
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,22 @@
+include config.mk
+
+TARGET = free
+SRC = free.c
+
+all: ${TARGET}
+
+clean:
+	rm -f *.[oa] ${TARGET}
+
+install: all
+	mkdir -p ${PREFIX}/bin
+	cp -f ${TARGET} ${PREFIX}/bin
+	chmod 755 ${PREFIX}/bin/${TARGET}
+	mkdir -p ${MANPREFIX}/man1
+	cp -f ${TARGET}.1 ${MANPREFIX}/man1
+	chmod 644 ${MANPREFIX}/man1/${TARGET}.1
+
+uninstall:
+	rm -f ${PREFIX}/bin/${TARGET} ${MANPREFIX}/man1/${TARGET}.1
+
+.PHONY: all clean install uninstall
diff --git a/config.mk b/config.mk
new file mode 100644
index 0000000..ed60c37
--- /dev/null
+++ b/config.mk
@@ -0,0 +1,7 @@
+PREFIX = /usr/local
+MANPREFIX = ${PREFIX}/share/man
+
+CFLAGS = -Wall -Wextra -Wpedantic -O2 -lkvm
+LDFLAGS =
+
+CC = cc
diff --git a/free.1 b/free.1
new file mode 100644
index 0000000..b623262
--- /dev/null
+++ b/free.1
@@ -0,0 +1,46 @@
+.Dd May 2026
+.Dt FREE 1
+.Os
+.Sh NAME
+.Nm free
+.Nd display amount of free and used memory in the system
+.Sh SYNOPSIS
+.Nm
+.Op Fl bghkmpt
+.Sh DESCRIPTION
+.Nm
+displays the total amount of free and used physical and swap memory in the system, as
+well as the buffers, caches (including ZFS ARC) and wired memory used by the kernel.
+The displayed columns are:
+.Bl -tag -width -indent
+.It total
+Total usable memory.
+.It used
+Unavailable memory.
+.It free
+Truly unallocated memory.
+.It wired
+Memory that can't be swapped to disk.
+.It buff/cache
+Memory used by kernel buffers, traditional FS cache and ARC.
+.It available
+Available memory.
+.Sh OPTIONS
+.Bl -tag -width ".Fl b "
+.It Fl b
+Display in bytes.
+.It Fl k
+Display in kibibytes.
+.It Fl m
+Display in mebibytes.
+.It Fl g
+Display in gibibytes.
+.It Fl t
+Display in tebibytes.
+.It Fl p
+Display in pebytes.
+.It Fl h
+Display in human-readable units.
+.Sh SEE ALSO
+.Xr top 1 ,
+.Xr sysctl 1
diff --git a/free.c b/free.c
new file mode 100644
index 0000000..971711b
--- /dev/null
+++ b/free.c
@@ -0,0 +1,233 @@
+#include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <err.h>
+#include <kvm.h>
+
+typedef enum {
+	NO_CONV,
+	KB_CONV,
+	MB_CONV,
+	GB_CONV,
+	TB_CONV,
+	PB_CONV,
+	HU_CONV
+} ConvFlags;
+
+static kvm_t *kd;
+static long pgsz;
+static char sbuff[32];
+
+void
+usage(void)
+{
+	fprintf(stderr, "usage: %s [-bghkmpt]\n", getprogname());
+	exit(2);
+}
+
+long long
+getphysmem(int unused)
+{
+	(void)unused;
+
+	long long physcnt;
+	size_t len = sizeof(physcnt);
+
+	if (sysctlbyname("hw.physmem", &physcnt, &len, NULL, 0) < 0)
+		err(1, "hw.physmem");
+
+	return physcnt;
+}
+
+long long
+getavailmem(int flag)
+{
+	size_t len;
+	unsigned int freecnt, inactcnt;
+
+	len = sizeof(freecnt);
+	if (sysctlbyname("vm.stats.vm.v_free_count", &freecnt, &len, NULL, 0) < 0)
+		err(1, "vm.stats.vm.v_free_count");
+	if (sysctlbyname("vm.stats.vm.v_inactive_count", &inactcnt, &len, NULL, 0) < 0)
+		err(1, "vm.stats.vm.v_inactive_count");
+
+	if (flag == 1)
+		return (long long)(getphysmem(0) - (freecnt + inactcnt) * pgsz);
+	else if (flag == 2)
+		return (long long)(freecnt * pgsz);
+	else
+		return (long long)((freecnt + inactcnt) * pgsz);
+}
+
+long long
+getwiredmem(int unused)
+{
+	(void)unused;
+
+	size_t len;
+	unsigned int wirecnt;
+
+	len = sizeof(wirecnt);
+	if (sysctlbyname("vm.stats.vm.v_wire_count", &wirecnt, &len, NULL, 0) < 0)
+		err(1, "vm.stats.vm.v_wire_count");
+
+	return (long long)(wirecnt * pgsz);
+
+}
+
+long long
+getbufcachestats(int unused)
+{
+	(void)unused;
+
+	size_t len;
+	long bufspace, arcspace;
+	unsigned int cachecnt;
+
+	len = sizeof(bufspace);
+	if (sysctlbyname("vfs.bufspace", &bufspace, &len, NULL, 0) < 0)
+		err(1, "vfs.bufspace");
+	/* Ignore failure in case ZFS is not used */
+	(void)sysctlbyname("kstat.zfs.misc.arcstats.size", &arcspace, &len, NULL, 0);
+
+	len = sizeof(cachecnt);
+	if (sysctlbyname("vm.stats.vm.v_cache_count", &cachecnt, &len, NULL, 0) < 0)
+		err(1, "vm.stats.vm.v_inactive_count");
+
+	return (long long)(cachecnt * pgsz + bufspace + arcspace);
+}
+
+long long
+getswapstats(int flag)
+{
+	int nswap;
+	struct kvm_swap swap;
+
+	if ((nswap = kvm_getswapinfo(kd, &swap, 1, 0)) < 0)
+		errx(1, "kvm_getswapinfo: %s", kvm_geterr(kd));
+
+	if (flag == 0)
+		return (long long)(swap.ksw_total * pgsz);
+	else if (flag == 1)
+		return (long long)(swap.ksw_used * pgsz);
+	else
+		return (long long)((swap.ksw_total - swap.ksw_used) * pgsz);
+}
+
+int
+tohumansize(long long bytes, char **buff, ConvFlags flag)
+{
+	int i = 0;
+	double size = (double)bytes;
+	char units[] = {'\0', 'K', 'M', 'G', 'T', 'P'};
+
+	if (flag != HU_CONV)
+		memset(units, '\0', sizeof(units));
+	if (flag == NO_CONV)
+		return asprintf(buff, "%.0f", size);
+
+	while (i < (int)flag) {
+		if (size <= 1024 && flag == HU_CONV) break;
+		size /= 1024;
+		i++;
+	}
+
+	if (i == 0 || size < 0.1)
+		return asprintf(buff, "%.0f", size);
+	else if (size < 10)
+		return asprintf(buff, "%.1f%c", size, units[i]);
+	else
+		return asprintf(buff, "%.0f%c", size, units[i]);
+}
+
+void
+sprintfaligned(char *buff, size_t len)
+{
+	size_t blen;
+	char *ind;
+
+	blen = strlen(buff);
+	ind = sbuff + len - blen;
+	if (ind < sbuff) {
+		size_t t = sbuff - ind;
+		ind = sbuff;
+		*ind = '%';
+		ind++; buff += t;
+		blen = 30;
+	}
+	strlcpy(ind, buff, blen + 1);
+
+	return;
+}
+
+int
+main(int argc, char *argv[])
+{
+	int c, i;
+	char *buff;
+	size_t offset;
+	ConvFlags flags;
+	long long (*getmemstats[])(int) =
+		{getphysmem, getavailmem, getavailmem, getwiredmem, getbufcachestats, getavailmem};
+
+	flags = KB_CONV;
+	while ((c = getopt(argc, argv, "bghkmpt")) >= 0) {
+		switch(c) {
+		case 'b':
+			flags = NO_CONV; break;
+		case 'k':
+			flags = KB_CONV; break;
+		case 'm':
+			flags = MB_CONV; break;
+		case 'g':
+			flags = GB_CONV; break;
+		case 't':
+			flags = TB_CONV; break;
+		case 'p':
+			flags = PB_CONV; break;
+		case 'h':
+			flags = HU_CONV; break;
+		default:
+			usage();
+		}
+	}
+
+	pgsz = sysconf(_SC_PAGESIZE);
+
+	/* initializing kvm device for swap stats */
+	if (!(kd = kvm_open(NULL, "/dev/null", NULL, 0, "kvm_open")))
+		err(1, "kvm_open");
+
+	printf("%16s%12s%12s%12s%12s%12s\nMem:",
+	       "total", "used", "free", "wired", "buff/cache", "available");
+
+	offset = 12;
+	for (i = 0; i < 6; i++) {
+		memset(sbuff, ' ', sizeof(sbuff));
+		tohumansize(getmemstats[i](i), &buff, flags);
+		sprintfaligned(buff, offset);
+		printf("%s", sbuff);
+		free(buff);
+	}
+
+	offset = 11;
+	printf("\nSwap:");
+	for (i = 0; i < 3; i++) {
+		memset(sbuff, ' ', sizeof(sbuff));
+		tohumansize(getswapstats(i), &buff, flags);
+		sprintfaligned(buff, offset);
+		printf("%s", sbuff);
+		free(buff);
+		offset = 12;
+	}
+	putc('\n', stdout);
+
+	return 0;
+}