]> git.tdb.fi Git - pmount-gui.git/blobdiff - main.c
Add a bunch of comments to the code
[pmount-gui.git] / main.c
diff --git a/main.c b/main.c
index 6be83527e43da5809cace5ad328f1f0eff36f286..f8b4c2ef664eabe93f1c92f0fa5fb2b062f19e56 100644 (file)
--- a/main.c
+++ b/main.c
@@ -1,3 +1,5 @@
+/* Required for strdup, snprintf, getopt */
+#define _XOPEN_SOURCE 500
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -7,7 +9,9 @@
 #include <mntent.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <sys/select.h>
 #include <gtk/gtk.h>
+#include <gdk/gdkkeysyms.h>
 
 typedef struct sProperty
 {
@@ -26,6 +30,10 @@ typedef struct sDevice
 
 int verbosity = 0;
 
+/**
+Parses a string of the form name=value and places the components in a Property
+structure.  Returns 0 on success, or -1 if the string wasn't a valid property.
+*/
 int parse_property(char *str, int size, Property *prop)
 {
        int equals = -1;
@@ -49,6 +57,11 @@ int parse_property(char *str, int size, Property *prop)
        return 0;
 }
 
+/**
+Retrieves all properties associated with a /dev node.  The returned array is
+terminated with an entry containing NULL values.  Use free_properties to free
+the array.
+*/
 Property *get_device_properties(char *node)
 {
        int pid;
@@ -59,6 +72,7 @@ Property *get_device_properties(char *node)
        pid = fork();
        if(pid==0)
        {
+               /* Child process */
                if(verbosity>=2)
                        printf("Running udevadm info -q property -n \"%s\"\n", node);
 
@@ -70,6 +84,7 @@ Property *get_device_properties(char *node)
        }
        else if(pid>0)
        {
+               /* Parent process */
                char *buf;
                int bufsize;
                int pos = 0;
@@ -109,6 +124,9 @@ Property *get_device_properties(char *node)
                        {
                                if(eof)
                                        break;
+
+                               /* There was no newline in the buffer but there is more output to
+                               be read.  Try again with a larger buffer. */
                                bufsize *= 2;
                                buf = (char *)realloc(buf, bufsize);
                                continue;
@@ -116,6 +134,7 @@ Property *get_device_properties(char *node)
 
                        if(parse_property(buf, newline, &prop)==0)
                        {
+                               /* Reserve space for a sentinel value as well. */
                                props = (Property *)realloc(props, (n_props+2)*sizeof(Property));
                                props[n_props] = prop;
                                ++n_props;
@@ -131,6 +150,7 @@ Property *get_device_properties(char *node)
 
                if(props)
                {
+                       /* Terminate the array with NULL pointers. */
                        props[n_props].name = NULL;
                        props[n_props].value = NULL;
                }
@@ -149,6 +169,10 @@ Property *get_device_properties(char *node)
        }
 }
 
+/**
+Looks for a property in an array of properties and returns its value.  Returns
+NULL if the property was not found.
+*/
 char *get_property_value(Property *props, char *name)
 {
        int i;
@@ -158,6 +182,10 @@ char *get_property_value(Property *props, char *name)
        return NULL;
 }
 
+/**
+Checks if a property has a specific value.  A NULL value is matched if the
+property does not exist.
+*/
 int match_property_value(Property *props, char *name, char *value)
 {
        char *v = get_property_value(props, name);
@@ -166,6 +194,9 @@ int match_property_value(Property *props, char *name, char *value)
        return strcmp(v, value)==0;
 }
 
+/**
+Frees an array of properties and all strings contained in it.
+*/
 void free_properties(Property *props)
 {
        int i;
@@ -179,49 +210,89 @@ void free_properties(Property *props)
        free(props);
 }
 
-char **get_mounted_devices(void)
+/**
+Reads device names from an fstab/mtab file.
+*/
+char **get_mount_entries(char *filename, int (*predicate)(struct mntent *))
 {
-       FILE *mtab;
+       FILE *file;
        struct mntent *me;
-       char **mounted = NULL;
-       int n_mounted = 0;
+       char **devices = NULL;
+       int n_devices = 0;
 
-       mtab = setmntent("/etc/mtab", "r");
-       if(!mtab)
+       file = setmntent(filename, "r");
+       if(!file)
                return NULL;
 
-       while((me = getmntent(mtab)))
-       {
-               mounted = (char **)realloc(mounted, (n_mounted+2)*sizeof(char *));
-               mounted[n_mounted] = strdup(me->mnt_fsname);
-               ++n_mounted;
-       }
+       while((me = getmntent(file)))
+               if(!predicate || predicate(me))
+               {
+                       devices = (char **)realloc(devices, (n_devices+2)*sizeof(char *));
+                       devices[n_devices] = strdup(me->mnt_fsname);
+                       ++n_devices;
+               }
 
-       endmntent(mtab);
-       mounted[n_mounted] = NULL;
+       endmntent(file);
+       if(devices)
+               devices[n_devices] = NULL;
 
-       return mounted;
+       return devices;
+}
+
+/**
+Returns an array of all currently mounted devices.
+*/
+char **get_mounted_devices(void)
+{
+       return get_mount_entries("/etc/mtab", NULL);
 }
 
-int is_mounted(char **mounted, char *devname)
+/**
+Checks if an fstab entry has the user option set.
+*/
+int is_user_mountable(struct mntent *me)
+{
+       return hasmntopt(me, "user")!=NULL;
+}
+
+/**
+Returns an array of user-mountable devices listed in fstab.
+*/
+char **get_fstab_devices(void)
+{
+       return get_mount_entries("/etc/fstab", &is_user_mountable);
+}
+
+/**
+Checks if an array of strings contains the specified string.
+*/
+int is_in_array(char **array, char *str)
 {
        int i;
-       for(i=0; mounted[i]; ++i)
-               if(!strcmp(devname, mounted[i]))
+       if(!array || !str)
+               return 0;
+       for(i=0; array[i]; ++i)
+               if(!strcmp(str, array[i]))
                        return 1;
        return 0;
 }
 
-void free_mounted_devices(char **mounted)
+/**
+Frees an array of strings.
+*/
+void free_string_array(char **array)
 {
        int i;
-       if(!mounted)
+       if(!array)
                return;
-       for(i=0; mounted[i]; ++i)
-               free(mounted[i]);
-       free(mounted);
+       for(i=0; array[i]; ++i)
+               free(array[i]);
+       free(array);
 }
 
+/**
+Checks if a partition identified by a sysfs path is on a removable device.
+*/
 int is_removable(char *devpath)
 {
        char fnbuf[256];
@@ -230,11 +301,15 @@ int is_removable(char *devpath)
        int fd;
 
        len = snprintf(fnbuf, sizeof(fnbuf), "/sys%s", devpath);
+       /* Default to not removable if the path was too long. */
        if(len+10>=(int)sizeof(fnbuf))
                return 0;
 
+       /* We got a partition as a parameter, but the removable property is on the
+       disk.  Replace the last component with "removable". */
        for(ptr=fnbuf+len; (ptr>fnbuf && *ptr!='/'); --ptr) ;
        strcpy(ptr, "/removable");
+
        fd = open(fnbuf, O_RDONLY);
        if(fd!=-1)
        {
@@ -254,6 +329,11 @@ int is_removable(char *devpath)
        return 0;
 }
 
+/**
+Checks if a partition's disk or any of its parent devices are connected to any
+of a set of buses.  The device is identified by a sysfs path.  The bus array
+must be terminated with a NULL entry.
+*/
 int check_buses(char *devpath, char **buses)
 {
        char fnbuf[256];
@@ -261,6 +341,7 @@ int check_buses(char *devpath, char **buses)
        int len;
 
        len = snprintf(fnbuf, sizeof(fnbuf), "/sys%s", devpath);
+       /* Default to no match if the path was too long. */
        if(len+10>=(int)sizeof(fnbuf))
                return 0;
 
@@ -268,32 +349,52 @@ int check_buses(char *devpath, char **buses)
                if(*ptr=='/')
                {
                        char linkbuf[256];
+                       /* Replace the last component with "subsystem". */
                        strcpy(ptr, "/subsystem");
                        len = readlink(fnbuf, linkbuf, sizeof(linkbuf)-1);
-                       *ptr = 0;
 
                        if(len!=-1)
                        {
-                               int i;
                                linkbuf[len] = 0;
+                               /* Extract the last component of the subsystem symlink. */
                                for(; (len>0 && linkbuf[len-1]!='/'); --len) ;
+
                                if(verbosity>=2)
+                               {
+                                       *ptr = 0;
                                        printf("  Subsystem of %s is %s\n", fnbuf, linkbuf+len);
-                               for(i=0; buses[i]; ++i)
-                                       if(strcmp(linkbuf+len, buses[i])==0)
-                                               return 1;
+                               }
+
+                               if(is_in_array(buses, linkbuf+len))
+                                       return 1;
                        }
                }
 
        return 0;
 }
 
-int can_mount(Property *props)
+/**
+Check if an array of properties describes a device that can be mounted.  An
+array of explicitly allowed devices can be passed in as well.  Both arrays must
+be terminated by a NULL entry.
+*/
+int can_mount(Property *props, char **allowed)
 {
        static char *removable_buses[] = { "usb", "firewire", 0 };
+       char *devname;
        char *devpath;
-       int i;
+       char *bus;
 
+       devname = get_property_value(props, "DEVNAME");
+       if(is_in_array(allowed, devname))
+               return 1;
+
+       /* Special case for CD devices, since they are not partitions.  Only allow
+       mounting if media is inserted. */
+       if(match_property_value(props, "ID_TYPE", "cd") && match_property_value(props, "ID_CDROM_MEDIA", "1"))
+               return 1;
+
+       /* Only allow mounting partitions. */
        if(!match_property_value(props, "DEVTYPE", "partition"))
                return 0;
 
@@ -301,13 +402,20 @@ int can_mount(Property *props)
        if(is_removable(devpath))
                return 1;
 
-       for(i=0; removable_buses[i]; ++i)
-               if(match_property_value(props, "ID_BUS", removable_buses[i]))
-                       return 1;
+       /* Certain buses are removable by nature, but devices only advertise
+       themselves as removable if they support removable media, e.g. memory card
+       readers. */
+       bus = get_property_value(props, "ID_BUS");
+       if(is_in_array(removable_buses, bus))
+               return 1;
 
        return check_buses(devpath, removable_buses);
 }
 
+/**
+Returns an array of all device nodes in a directory.  Symbolic links are
+dereferenced.
+*/
 char **get_device_nodes(char *dirname)
 {
        DIR *dir;
@@ -330,6 +438,7 @@ char **get_device_nodes(char *dirname)
                char *node;
                int duplicate = 0;
 
+               /* Ignore . and .. entries. */
                if(de->d_name[0]=='.' && (de->d_name[1]==0 || (de->d_name[1]=='.' && de->d_name[2]==0)))
                        continue;
 
@@ -348,6 +457,8 @@ char **get_device_nodes(char *dirname)
                        }
                }
 
+               /* There may be multiple symlinks to the same device.  Only include each
+               device once in the returned array. */
                if(checked)
                {
                        for(i=0; (!duplicate && i<n_checked); ++i)
@@ -356,7 +467,7 @@ char **get_device_nodes(char *dirname)
                }
                if(duplicate)
                {
-                       if(verbosity>=1)
+                       if(verbosity>=2)
                                printf("Device %s is a duplicate\n", fnbuf);
                        continue;
                }
@@ -384,23 +495,28 @@ char **get_device_nodes(char *dirname)
        return nodes;
 }
 
+/** Returns an array of all mountable devices. */
 Device *get_devices(void)
 {
        char **nodes = NULL;
        Device *devices = NULL;
        int n_devices = 0;
        char **mounted = NULL;
+       char **fstab = NULL;
        int i;
 
        nodes = get_device_nodes("/dev/disk/by-id");
        mounted = get_mounted_devices();
+       fstab = get_fstab_devices();
 
        for(i=0; nodes[i]; ++i)
        {
+               Property *props;
+
                if(verbosity>=1)
                        printf("Examining device %s\n", nodes[i]);
 
-               Property *props = get_device_properties(nodes[i]);
+               props = get_device_properties(nodes[i]);
                if(!props)
                {
                        if(verbosity>=2)
@@ -415,7 +531,7 @@ Device *get_devices(void)
                                printf("  %s = %s\n", props[j].name, props[j].value);
                }
 
-               if(can_mount(props))
+               if(can_mount(props, fstab))
                {
                        char *devname;
                        char *label;
@@ -430,6 +546,8 @@ Device *get_devices(void)
 
                        devname = get_property_value(props, "DEVNAME");
 
+                       /* Get a human-readable label for the device.  Use filesystem label,
+                       filesystem UUID or device node name in order of preference. */
                        label = get_property_value(props, "ID_FS_LABEL");
                        if(!label)
                                label = get_property_value(props, "ID_FS_UUID");
@@ -452,11 +570,12 @@ Device *get_devices(void)
 
                        stat(nodes[i], &st);
 
+                       /* Reserve space for a sentinel entry. */
                        devices = (Device *)realloc(devices, (n_devices+2)*sizeof(Device));
                        devices[n_devices].node = nodes[i];
                        devices[n_devices].label = strdup(label);
                        devices[n_devices].description = strdup(buf);
-                       devices[n_devices].mounted = is_mounted(mounted, devname);
+                       devices[n_devices].mounted = is_in_array(mounted, devname);
                        devices[n_devices].time = st.st_mtime;
                        ++n_devices;
                }
@@ -466,10 +585,11 @@ Device *get_devices(void)
        }
 
        free(nodes);
-       free_mounted_devices(mounted);
+       free_string_array(mounted);
 
        if(devices)
        {
+               /* Terminate the array with NULL pointers. */
                devices[n_devices].node = NULL;
                devices[n_devices].label = NULL;
                devices[n_devices].description = NULL;
@@ -478,6 +598,9 @@ Device *get_devices(void)
        return devices;
 }
 
+/**
+Frees an array of devices and all strings contained in it.
+*/
 void free_devices(Device *devices)
 {
        int i;
@@ -492,6 +615,10 @@ void free_devices(Device *devices)
        free(devices);
 }
 
+/**
+Callback for activating a row in the device list.  Mounts or unmounts the
+device depending on operating mode.
+*/
 void row_activated(GtkTreeView *list, GtkTreePath *path, GtkTreeViewColumn *column, gpointer user_data)
 {
        GtkTreeModel *model;
@@ -513,7 +640,8 @@ void row_activated(GtkTreeView *list, GtkTreePath *path, GtkTreeViewColumn *colu
                pid = fork();
                if(pid==0)
                {
-                       if(verbosity>=2)
+                       /* Child process */
+                       if(verbosity>=1)
                        {
                                if(umount)
                                        printf("Running pumount %s\n", device->node);
@@ -533,29 +661,65 @@ void row_activated(GtkTreeView *list, GtkTreePath *path, GtkTreeViewColumn *colu
                }
                else if(pid>0)
                {
+                       /* Parent process */
                        char buf[1024];
                        int pos = 0;
-                       int status;
+                       int status = 0;
+                       fd_set fds;
+                       struct timeval timeout;
 
                        close(pipe_fd[1]);
+                       FD_ZERO(&fds);
+                       FD_SET(pipe_fd[0], &fds);
+                       timeout.tv_sec = 0;
+                       timeout.tv_usec = 200000;
 
                        while(1)
                        {
-                               int len;
+                               /* The write fd for the pipe may be inherited by a fuse server
+                               process and stay open indefinitely. */
+                               if(select(pipe_fd[0]+1, &fds, NULL, NULL, &timeout))
+                               {
+                                       int len;
 
-                               len = read(pipe_fd[0], buf+pos, sizeof(buf)-pos-1);
-                               if(len<=0)
+                                       len = read(pipe_fd[0], buf+pos, sizeof(buf)-pos-1);
+                                       if(len<=0)
+                                               break;
+                                       pos += len;
+                               }
+                               else if(waitpid(pid, &status, 0))
+                               {
+                                       pid = 0;
                                        break;
-                               pos += len;
+                               }
                        }
 
+                       if(pid)
+                               waitpid(pid, &status, 0);
+
                        buf[pos] = 0;
 
-                       waitpid(pid, &status, 0);
+                       if(verbosity>=1)
+                       {
+                               if(WIFEXITED(status))
+                               {
+                                       if(WEXITSTATUS(status))
+                                               printf("Command exited successfully\n");
+                                       else
+                                               printf("Command exited with status %d\n", WEXITSTATUS(status));
+                               }
+                               else if(WIFSIGNALED(status))
+                                       printf("Command terminated with signal %d\n", WTERMSIG(status));
+                               else
+                                       printf("Command exited with unknown result %04X\n", status);
+                       }
+
                        if(!WIFEXITED(status) || WEXITSTATUS(status))
                        {
                                GtkWidget *dialog;
 
+                               /* Pmount terminated with nonzero status or a signal.  Display an
+                               error to the user. */
                                dialog = gtk_message_dialog_new(NULL, 0, GTK_MESSAGE_ERROR, GTK_BUTTONS_OK, "%s", buf);
                                g_signal_connect(dialog, "response", &gtk_main_quit, NULL);
                                gtk_widget_show_all(dialog);
@@ -563,21 +727,58 @@ void row_activated(GtkTreeView *list, GtkTreePath *path, GtkTreeViewColumn *colu
                        else
                                gtk_main_quit();
                }
-               else
-               {
-               }
        }
 
        (void)column;
 }
 
+/**
+Callback for the mount/unmount button.  Causes the selected row in the device
+list to be activated.
+*/
+void button_clicked(GtkButton *button, gpointer user_data)
+{
+       GtkWidget *list = (GtkWidget *)user_data;
+       GtkTreeSelection *selection;
+       GtkTreeIter iter;
+       GtkTreeModel *model;
+       GtkTreePath *path;
+
+       selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(list));
+       gtk_tree_selection_get_selected(selection, &model, &iter);
+       path = gtk_tree_model_get_path(model, &iter);
+       gtk_tree_view_row_activated(GTK_TREE_VIEW(list), path, gtk_tree_view_get_column(GTK_TREE_VIEW(list), 0));
+       gtk_tree_path_free(path);
+
+       (void)button;
+}
+
+/**
+Global key press callback for the window.
+*/
+gboolean key_press(GtkWidget *widget, GdkEvent *event, gpointer user_data)
+{
+       if(event->key.keyval==GDK_KEY_Escape)
+       {
+               gtk_main_quit();
+               return TRUE;
+       }
+
+       (void)widget;
+       (void)user_data;
+
+       return FALSE;
+}
+
 int main(int argc, char **argv)
 {
        GtkWidget *window;
+       GtkWidget *box;
        GtkWidget *viewport;
        GtkWidget *list;
        GtkListStore *store;
        GtkTreeSelection *selection;
+       GtkWidget *button;
        GtkTreeIter iter;
        Device *devices;
        int i;
@@ -600,15 +801,19 @@ int main(int argc, char **argv)
 
        window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
        gtk_container_set_border_width(GTK_CONTAINER(window), 5);
-       g_signal_connect(window, "destroy", &gtk_main_quit, NULL);
+       g_signal_connect(window, "destroy", G_CALLBACK(&gtk_main_quit), NULL);
+       g_signal_connect(window, "key-press-event", G_CALLBACK(&key_press), NULL);
+
+       box = gtk_vbox_new(FALSE, 5);
+       gtk_container_add(GTK_CONTAINER(window), box);
 
        viewport = gtk_viewport_new(NULL, NULL);
        gtk_viewport_set_shadow_type(GTK_VIEWPORT(viewport), GTK_SHADOW_IN);
-       gtk_container_add(GTK_CONTAINER(window), viewport);
+       gtk_box_pack_start(GTK_BOX(box), viewport, TRUE, TRUE, 0);
 
        list = gtk_tree_view_new();
        gtk_container_add(GTK_CONTAINER(viewport), list);
-       g_signal_connect(list, "row-activated", (GCallback)&row_activated, &umount);
+       g_signal_connect(list, "row-activated", G_CALLBACK(&row_activated), &umount);
 
        store = gtk_list_store_new(2, G_TYPE_STRING, G_TYPE_POINTER);
        gtk_tree_view_set_model(GTK_TREE_VIEW(list), GTK_TREE_MODEL(store));
@@ -617,10 +822,15 @@ int main(int argc, char **argv)
 
        selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(list));
 
+       button = gtk_button_new_with_label(umount ? "Unmount" : "Mount");
+       g_signal_connect(button, "clicked", G_CALLBACK(&button_clicked), list);
+       gtk_box_pack_start(GTK_BOX(box), button, FALSE, TRUE, 0);
+
        devices = get_devices();
        n_listed = 0;
        if(devices)
        {
+               /* Populate the list with devices in appropriate state. */
                latest = 0;
                for(i=0; devices[i].node; ++i)
                        if(!devices[i].mounted==!umount)
@@ -629,6 +839,7 @@ int main(int argc, char **argv)
                                gtk_list_store_set(store, &iter, 0, devices[i].description, 1, &devices[i], -1);
                                if(devices[i].time>latest)
                                {
+                                       /* Pre-select the device that appeared on the system most recently. */
                                        latest = devices[i].time;
                                        gtk_tree_selection_select_iter(selection, &iter);
                                }
@@ -644,9 +855,10 @@ int main(int argc, char **argv)
        {
                GtkWidget *dialog;
 
+               /* Don't show the main window if no devices were listed. */
                dialog = gtk_message_dialog_new(NULL, 0, GTK_MESSAGE_WARNING, GTK_BUTTONS_OK,
                        "No devices to %s", (umount ? "unmount" : "mount"));
-               g_signal_connect(dialog, "response", &gtk_main_quit, NULL);
+               g_signal_connect(dialog, "response", G_CALLBACK(&gtk_main_quit), NULL);
                gtk_widget_show_all(dialog);
        }