From e148d614122d038760b1ed90278956a5d577f3df Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 5 Nov 2011 00:24:11 +0530
Subject: [PATCH] calibre-mount-helper: A nicer mount point location check

---
 src/calibre/devices/linux_mount_helper.c | 35 ++++++++++++++++++++++--
 src/calibre/devices/usbms/device.py      | 10 +++++--
 2 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/src/calibre/devices/linux_mount_helper.c b/src/calibre/devices/linux_mount_helper.c
index dfeaa7985e..eefbd1ffcc 100644
--- a/src/calibre/devices/linux_mount_helper.c
+++ b/src/calibre/devices/linux_mount_helper.c
@@ -8,6 +8,7 @@
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <fcntl.h>
+#include <strings.h>
 
 #define MARKER ".created_by_calibre_mount_helper"
 #define DEV "/dev/"
@@ -272,6 +273,37 @@ void check_dev(const char *dev) {
 
 }
 
+char *get_real_mount_point(const char *mp) {
+    /* Resolve the mount point to a canonical path. Assumes that mp 
+     * either points to an existing directory, or only the leaf node 
+     * of mp does not exist. This is safe for the usage scenario of calibre-mount-helper. */ 
+    char *dirname = NULL, *basename, *p, *buffer;
+    buffer = calloc(PATH_MAX+1, sizeof(char));
+    if (buffer == NULL) exit(EXIT_FAILURE);
+    if (realpath(mp, buffer) != NULL) return buffer;
+
+    dirname = calloc(PATH_MAX+1, sizeof(char));
+    if (dirname == NULL) exit(EXIT_FAILURE);
+
+    strncpy(dirname, mp, PATH_MAX);
+    p = rindex(dirname, '/');
+    if (p == NULL) {
+        fprintf(stderr, "mountpoint must have atleast one /\n"); 
+        exit(EXIT_FAILURE);
+    }
+    basename = p+1;
+    *p = 0;
+    dirname = realpath(dirname, NULL);
+    if (dirname == NULL) {
+        fprintf(stderr, "parent directory of mount point cannot be resolved, ensure the mountpoint does not have a trailing slash.\n");
+        exit(EXIT_FAILURE);
+    }
+    snprintf(buffer, PATH_MAX, "%s/%s", dirname, basename);
+    free(dirname);
+    return buffer;
+}
+
+
 int main(int argc, char** argv)
 {
     char *action, *dev, *mp, *temp;
@@ -303,8 +335,7 @@ int main(int argc, char** argv)
             fprintf(stderr, "Failed to resolve device node.\n");
             exit(EXIT_FAILURE);
         }
-        temp = realpath(mp, NULL);
-        if (temp != NULL) mp = temp;
+        mp = get_real_mount_point(mp);
         check_dev(dev); check_mount_point(mp);
         status = do_mount(dev, mp);
     } else if (strncmp(action, "eject", 5) == 0) {
diff --git a/src/calibre/devices/usbms/device.py b/src/calibre/devices/usbms/device.py
index e6120f337f..0e899517a9 100644
--- a/src/calibre/devices/usbms/device.py
+++ b/src/calibre/devices/usbms/device.py
@@ -622,8 +622,11 @@ class Device(DeviceConfig, DevicePlugin):
                 if getattr(sys, 'frozen', False):
                     cmd = os.path.join(sys.executables_location, 'bin', cmd)
                 cmd = [cmd, 'mount']
+                mlabel = label
+                if mlabel.endswith('/'):
+                    mlabel = mlabel[:-1]
                 try:
-                    p = subprocess.Popen(cmd + [node, '/media/'+label])
+                    p = subprocess.Popen(cmd + [node, '/media/'+mlabel])
                 except OSError:
                     raise DeviceError(
                     _('Could not find mount helper: %s.')%cmd[0])
@@ -777,9 +780,12 @@ class Device(DeviceConfig, DevicePlugin):
             # try all the nodes to see what we can mount
             for dev in devs[i].split():
                 mp='/media/'+label+'-'+dev
+                mmp = mp
+                if mmp.endswith('/'):
+                    mmp = mmp[:-1]
                 #print "trying ", dev, "on", mp
                 try:
-                    p = subprocess.Popen(cmd + ["/dev/"+dev, mp])
+                    p = subprocess.Popen(cmd + ["/dev/"+dev, mmp])
                 except OSError:
                     raise DeviceError(_('Could not find mount helper: %s.')%cmd[0])
                 while p.poll() is None: