1 files changed, 116 insertions, 0 deletions
diff --git a/usr/kinit/devname.c b/usr/kinit/devname.c
new file mode 100644
index 0000000..c327e3b
--- /dev/null
+++ b/usr/kinit/devname.c
@@ -0,0 +1,116 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/sysmacros.h>
+
+#include "kinit.h"
+
+/*
+ * Print the name of a block device.
+ */
+#define BUF_SIZE	512
+
+static int scansysdir(char *namebuf, char *sysdir, dev_t dev)
+{
+	char *dirtailptr = strchr(sysdir, '\0');
+	DIR *dir;
+	int done = 0;
+	struct dirent *de;
+	char *systail;
+	FILE *sysdev;
+	unsigned long ma, mi;
+	char *ep;
+	ssize_t rd;
+
+	dir = opendir(sysdir);
+	if (!dir)
+		return 0;
+
+	*dirtailptr++ = '/';
+
+	while (!done && (de = readdir(dir))) {
+		/* Assume if we see a dot-name in sysfs it's special */
+		if (de->d_name[0] == '.')
+			continue;
+
+		if (de->d_type != DT_UNKNOWN && de->d_type != DT_DIR)
+			continue;
+
+		if (strlen(de->d_name) >=
+		    (BUF_SIZE - 64) - (dirtailptr - sysdir))
+			continue;	/* Badness... */
+
+		strcpy(dirtailptr, de->d_name);
+		systail = strchr(sysdir, '\0');
+
+		strcpy(systail, "/dev");
+		sysdev = fopen(sysdir, "r");
+		if (!sysdev)
+			continue;
+
+		/* Abusing the namebuf as temporary storage here. */
+		rd = fread(namebuf, 1, BUF_SIZE, sysdev);
+		namebuf[rd] = '\0';	/* Just in case... */
+
+		fclose(sysdev);
+
+		ma = strtoul(namebuf, &ep, 10);
+		if (ma != major(dev) || *ep != ':')
+			continue;
+
+		mi = strtoul(ep + 1, &ep, 10);
+		if (*ep != '\n')
+			continue;
+
+		if (mi == minor(dev)) {
+			/* Found it! */
+			strcpy(namebuf, de->d_name);
+			done = 1;
+		} else {
+			/* we have a major number match, scan for partitions */
+			*systail = '\0';
+			done = scansysdir(namebuf, sysdir, dev);
+		}
+	}
+
+	closedir(dir);
+	return done;
+}
+
+const char *bdevname(dev_t dev)
+{
+	static char buf[BUF_SIZE];
+	char sysdir[BUF_SIZE];
+	char *p;
+
+	strcpy(sysdir, "/sys/block");
+
+	if (!scansysdir(buf, sysdir, dev))
+		strcpy(buf, "dev");	/* prints e.g. dev(3,5) */
+
+	p = strchr(buf, '\0');
+	snprintf(p, sizeof buf - (p - buf), "(%d,%d)", major(dev), minor(dev));
+
+	return buf;
+}
+
+#ifdef TEST_DEVNAME		/* Standalone test */
+
+int main(int argc, char *argv[])
+{
+	dev_t dev;
+	int i;
+
+	for (i = 1; i < argc; i++) {
+		dev = strtoul(argv[i], NULL, 0);
+
+		printf("0x%08x = %s\n", (unsigned int)dev, bdevname(dev));
+	}
+
+	return 0;
+}
+
+#endif				/* TEST */