1 files changed, 140 insertions, 0 deletions
diff --git a/9umount.c b/9umount.c
new file mode 100644
index 0000000..1adc9fe
--- /dev/null
+++ b/9umount.c
@@ -0,0 +1,140 @@
+/* © 2008 sqweek <sqweek@gmail.com>
+ * See COPYING for details.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <err.h>
+
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <mntent.h>
+#include <pwd.h>
+
+char*
+canonpath(char *rel)
+{
+	char *abs, *cp, *prev;
+
+	if (rel[0] == '/') {
+		if (!(abs=malloc(strlen(rel) + 2))) {
+			return NULL;
+		}
+		abs[0] = '\0';
+		strcat(abs, rel);
+		strcat(abs, "/");
+	} else {
+		char *cwd = NULL;
+		if (!(cwd=getcwd(NULL, 0))) {
+			return NULL;
+		}
+		if (!(abs=malloc(strlen(cwd) + 1 + strlen(rel) + 2))) {
+			free(cwd);
+			return NULL;
+		}
+		abs[0] = '\0';
+		strcat(abs, cwd);
+		strcat(abs, "/");
+		strcat(abs, rel);
+		strcat(abs, "/");
+		free(cwd);
+	}
+
+	/* abs is now an absolute path which begins and ends with a slash */
+	prev = abs;
+	while ((cp=strchr(prev+1, '/'))) {
+		if (cp == prev+1) {
+			/* remove consecutive slashes */ 
+			memmove(prev, cp, strlen(cp)+1);
+		} else if (strncmp(prev, "/./", cp-prev+1) == 0) {
+			memmove(prev, cp, strlen(cp)+1);
+		} else if (strncmp(prev, "/../", cp-prev+1) == 0) {
+			char *parent;
+			if (prev == abs) {
+				parent = abs; /* just eat .. in root dir */
+			} else {
+				for (parent=prev-1; *parent != '/'; --parent);
+			}
+			memmove(parent, cp, strlen(cp)+1);
+			prev = parent;
+		} else {
+			prev = cp;
+		}
+	}
+	abs[strlen(abs)-1] = '\0'; /* remove trailing slash */
+
+	return abs;
+}
+
+int
+indir(struct mntent *mnt, char *dir)
+{
+	return (strncmp(mnt->mnt_dir, dir, strlen(dir)) == 0);
+}
+
+int
+mountedby(struct mntent *mnt, char *username)
+{
+	char *s, *cp;
+	if (!(s=strdup(mnt->mnt_opts))) {
+		errx(1, "out of memory");
+	}
+	for (cp=strtok(s, ","); cp; cp=strtok(NULL, ",")) {
+		if (strncmp(cp, "name=", 5) == 0) {
+			int eq = (strcmp(cp+5, username) == 0);
+			free(s);
+			return eq;
+		}
+	}
+	free(s);
+	return 0;
+}
+
+int
+main(int argc, char **argv)
+{
+	int ret = 0;
+	char *path;
+	FILE *fp;
+	struct mntent *mnt;
+	struct passwd *pw;
+
+	if (!(pw=getpwuid(getuid()))) {
+		err(1, "who are you?? getpwuid failed");
+	}
+
+	while (*++argv) {
+		if (!(path=canonpath(*argv))) {
+			warn("%s: canonpath", *argv);
+			continue;
+		}
+		if (!(fp=fopen("/proc/mounts", "r"))) {
+			err(1, "couldn't open /proc/mounts");
+		}
+		while ((mnt=getmntent(fp))) {
+			if (strcmp(path, mnt->mnt_dir) == 0) {
+				int inhomedir;
+				inhomedir = indir(mnt, pw->pw_dir);
+				if (!inhomedir && strcmp(mnt->mnt_type, "9p") != 0) {
+					warnx("%s: refusing to unmount non-9p fs", path);
+					ret = 1;
+				} else if (!inhomedir && !mountedby(mnt, pw->pw_name)) {
+					warnx("%s: not mounted by you", path);
+					ret = 1;
+				} else if (umount(mnt->mnt_dir)) {
+					warn("umount %s", mnt->mnt_dir);
+					ret = 1;
+				}
+				goto done;
+			}
+		}
+		warnx("%s not found in /proc/mounts", path);
+		ret = 1;
+
+done:
+		free(path);
+		fclose(fp);
+	}
+	return ret;
+}