X-Git-Url: http://git.draconx.ca/gitweb/liblbx.git/blobdiff_plain/5749c5e97a8b984720cef75f328944270874d713..c81b3f9cfa09bcf212214f006d879585774619e2:/src/tools.c

diff --git a/src/tools.c b/src/tools.c
index b80e521..200cf9c 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -19,6 +19,12 @@
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <limits.h>
+#include <inttypes.h>
 #include <assert.h>
 
 #include "tools.h"
@@ -46,3 +52,91 @@ const char *tool_invocation(void)
 	assert(argv0 != NULL);
 	return argv0;
 }
+
+/* Saturating addition. */
+static size_t add_size(size_t a, size_t b)
+{
+	if (a >= SIZE_MAX - b)
+		return SIZE_MAX;
+	return a + b;
+}
+
+static int vfmsg_internal(FILE *f, int err, const char *fmt, va_list ap)
+{
+	size_t invokelen, fmtlen, errlen, totlen;
+	char *newfmt, *errmsg;
+	int rc;
+
+	invokelen = strlen(tool_invocation());
+	fmtlen = fmt ? strlen(fmt) : 0;
+	errlen = err > 0 ? strlen(errmsg = strerror(err)) : 0;
+
+	totlen = add_size(invokelen, sizeof "\n");
+	if (fmtlen > 0) {
+		totlen = add_size(totlen, strlen(": "));
+		totlen = add_size(totlen, fmtlen);
+	}
+	if (errlen > 0) {
+		totlen = add_size(totlen, strlen(": "));
+		totlen = add_size(totlen, errlen);
+	}
+
+	if (totlen == SIZE_MAX || totlen > INT_MAX)
+		return -1;
+
+	newfmt = malloc(totlen);
+	if (!newfmt)
+		return -1;
+
+	if (errlen && fmtlen)
+		rc = sprintf(newfmt, "%s: %s: %s\n", argv0, fmt, errmsg);
+	else if (errlen)
+		rc = sprintf(newfmt, "%s: %s\n", argv0, errmsg);
+	else if (fmtlen)
+		rc = sprintf(newfmt, "%s: %s\n", argv0, fmt);
+	else
+		rc = sprintf(newfmt, "%s\n", argv0);
+
+	assert(rc < totlen);
+	if (rc < 0)
+		goto out;
+
+	rc = vfprintf(f, newfmt, ap);
+out:
+	free(newfmt);
+	return rc;
+}
+
+int tool_vmsg(const char *fmt, va_list ap)
+{
+	return vfmsg_internal(stdout, -1, fmt, ap);
+}
+
+int tool_verr(int err, const char *fmt, va_list ap)
+{
+	return vfmsg_internal(stderr, err == 0 ? errno : err, fmt, ap);
+}
+
+int tool_msg(const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = tool_vmsg(fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+int tool_err(int err, const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = tool_verr(err, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}