mvm: Add initial mvm groundwork

Signed-off-by: Ian Moffett <ian@mirocom.org>

mvm/.gitignore

@@ -0,0 +1 @@
+mvm

mvm/Makefile

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+#
+# Copyright (c) 2026 Mirocom Laboratories and MSP engineers.
+# All Rights Reserved.
+#
+
+CFILES = $(shell find core/ -name "*.c")
+OFILES = $(CFILES:.c=.o)
+DFILES = $(CFILES:.c=.d)
+CC = gcc
+
+CFLAGS	=		\
+	-Wall		\
+	-pedantic	\
+	-MMD		\
+	-Iinclude
+
+.PHONY: all
+all: mvm
+
+.PHONY: mvm
+mvm: $(OFILES)
+	$(CC) $^ -o $@
+
+%.o: %.c
+	$(CC) -c $(CFLAGS) $< -o $@

mvm/core/balloon_subr.c

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+/*
+ * Copyright (c) 2026 Mirocom Laboratories and MSP engineers.
+ * All Rights Reserved.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+#include "mvm/balloon.h"
+
+int
+balloon_init(struct mvm_balloon *bp, size_t cap)
+{
+    if (bp == NULL || cap == 0) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    assert(cap > BALLOON_INIT_SIZE && "cap must be bigger than minimum");
+    bp->cap = cap;
+    bp->size = BALLOON_INIT_SIZE;
+    bp->data = calloc(bp->size, sizeof(char));
+
+    if (bp->data == NULL) {
+        errno = ENOMEM;
+        return -1;
+    }
+
+    return 0;
+}
+
+int
+balloon_memcpy(struct mvm_balloon *dest, off_t off, void *source, size_t count)
+{
+    size_t overflow, newsize;
+    size_t delta;
+    void *p;
+
+    if (dest == NULL || source == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    if (count == 0) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    /* Compute how far off this will push us */
+    overflow = off + count;
+
+    /* If we are overflowing size and have room to expand, do it */
+    if (overflow >= dest->size && dest->size < dest->cap) {
+        delta = overflow - dest->size;
+        newsize = dest->size + delta;
+
+        /* Attempt to resize the pool */
+        if ((p = realloc(dest->data, newsize)) == NULL) {
+            errno = -ENOMEM;
+            return -1;
+        }
+
+        dest->size = newsize;
+        dest->data = p;
+    } else if (overflow >= dest->cap) {
+        errno = -ENOSPC;
+        return -1;
+    }
+
+    memcpy((char *)dest->data + off, source, count);
+    return 0;
+}

mvm/core/mvm.c

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+/*
+ * Copyright (c) 2026 Mirocom Laboratories and MSP engineers.
+ * All Rights Reserved.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include "mvm/balloon.h"
+
+static void
+help(void)
+{
+    printf("usage: ./mvm [flags]\n");
+    printf("[-h]    Display this help menu\n");
+}
+
+int
+main(int argc, char **argv)
+{
+    int opt;
+
+    if (argc < 2) {
+        printf("fatal: too few arguments\n");
+        help();
+        return -1;
+    }
+
+    while ((opt = getopt(argc, argv, "h")) != -1) {
+        switch (opt) {
+        case 'h':
+            help();
+            return -1;
+        }
+    }
+
+    return 0;
+}

mvm/include/mvm/balloon.h

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+/*
+ * Copyright (c) 2026 Mirocom Laboratories and MSP engineers.
+ * All Rights Reserved.
+ */
+
+#ifndef MVM_BALLOON_H
+#define MVM_BALLOON_H 1
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stddef.h>
+
+/* Initialize balloon size */
+#define BALLOON_INIT_SIZE 8
+
+/*
+ * A balloon is a region of memory that is capped at a specific
+ * maximum size and starts small before gradually growing as more
+ * data is added.
+ *
+ * @data:       Allocated data pool
+ * @cap:        Maximum capacity
+ * @size:       Current size
+ */
+struct mvm_balloon {
+    void *data;
+    size_t cap;
+    size_t size;
+};
+
+/*
+ * Create a new balloon
+ *
+ * @bp:  Balloon to create
+ * @cap: Maximum capacity of balloon
+ *
+ * Returns zero on success
+ */
+int balloon_init(struct mvm_balloon *bp, size_t cap);
+
+/*
+ * Copy a buffer into a balloon
+ *
+ * @dest:   Destination balloon
+ * @off:    Offset to write to
+ * @source: Source buffer
+ * @count:  Number of bytes to copy
+ *
+ * Returns zero on success
+ */
+int balloon_memcpy(struct mvm_balloon *dest, off_t off, void *source, size_t count);
+
+#endif  /* !MVM_BALLOON_H */