1 files changed, 133 insertions, 0 deletions
diff --git a/sysutils/mcelog/files/memstream.c b/sysutils/mcelog/files/memstream.c
new file mode 100644
index 000000000000..20cbf29b472c
--- /dev/null
+++ b/sysutils/mcelog/files/memstream.c
@@ -0,0 +1,133 @@
+/* Use funopen(3) to provide open_memstream(3) like functionality. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+struct memstream {
+	char **cp;
+	size_t *lenp;
+	size_t offset;
+};
+
+FILE *
+open_memstream(char **cp, size_t *lenp);
+
+static void
+memstream_grow(struct memstream *ms, size_t newsize)
+{
+	char *buf;
+
+	if (newsize > *ms->lenp) {
+		buf = realloc(*ms->cp, newsize + 1);
+		if (buf != NULL) {
+#ifdef DEBUG
+			fprintf(stderr, "MS: %p growing from %zd to %zd\n",
+			    ms, *ms->lenp, newsize);
+#endif
+			memset(buf + *ms->lenp + 1, 0, newsize - *ms->lenp);
+			*ms->cp = buf;
+			*ms->lenp = newsize;
+		}
+	}
+}
+
+static int
+memstream_read(void *cookie, char *buf, int len)
+{
+	struct memstream *ms;
+	int tocopy;
+
+	ms = cookie;
+	memstream_grow(ms, ms->offset + len);
+	tocopy = *ms->lenp - ms->offset;
+	if (len < tocopy)
+		tocopy = len;
+	memcpy(buf, *ms->cp + ms->offset, tocopy);
+	ms->offset += tocopy;
+#ifdef DEBUG
+	fprintf(stderr, "MS: read(%p, %d) = %d\n", ms, len, tocopy);
+#endif
+	return (tocopy);
+}
+
+static int
+memstream_write(void *cookie, const char *buf, int len)
+{
+	struct memstream *ms;
+	int tocopy;
+
+	ms = cookie;
+	memstream_grow(ms, ms->offset + len);
+	tocopy = *ms->lenp - ms->offset;
+	if (len < tocopy)
+		tocopy = len;
+	memcpy(*ms->cp + ms->offset, buf, tocopy);
+	ms->offset += tocopy;
+#ifdef DEBUG
+	fprintf(stderr, "MS: write(%p, %d) = %d\n", ms, len, tocopy);
+#endif
+	return (tocopy);
+}
+
+static fpos_t
+memstream_seek(void *cookie, fpos_t pos, int whence)
+{
+	struct memstream *ms;
+#ifdef DEBUG
+	size_t old;
+#endif
+
+	ms = cookie;
+#ifdef DEBUG
+	old = ms->offset;
+#endif
+	switch (whence) {
+	case SEEK_SET:
+		ms->offset = pos;
+		break;
+	case SEEK_CUR:
+		ms->offset += pos;
+		break;
+	case SEEK_END:
+		ms->offset = *ms->lenp + pos;
+		break;
+	}
+#ifdef DEBUG
+	fprintf(stderr, "MS: seek(%p, %zd, %d) %zd -> %zd\n", ms, pos, whence,
+	    old, ms->offset);
+#endif
+	return (ms->offset);
+}
+
+static int
+memstream_close(void *cookie)
+{
+
+	free(cookie);
+	return (0);
+}
+
+FILE *
+open_memstream(char **cp, size_t *lenp)
+{
+	struct memstream *ms;
+	int save_errno;
+	FILE *fp;
+
+	*cp = NULL;
+	*lenp = 0;
+	ms = malloc(sizeof(*ms));
+	ms->cp = cp;
+	ms->lenp = lenp;
+	ms->offset = 0;
+	fp = funopen(ms, memstream_read, memstream_write, memstream_seek,
+	    memstream_close);
+	if (fp == NULL) {
+		save_errno = errno;
+		free(ms);
+		errno = save_errno;
+	}
+	return (fp);
+}