libudev: device - fill envp array while composing monitor buffer

Thanks to Alan Jenkins, for the idea.

diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
index 513c65653bc76c17d8e7547ec6427d14db213f16..b8f4b8ba7127fc51868055fddba43bfb09f0ef8e 100644 (file)
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -31,8 +31,6 @@
 #include "libudev.h"
 #include "libudev-private.h"
 
-#define ENVP_SIZE 128
-
 struct udev_device {
        struct udev *udev;
        struct udev_device *parent_device;
@@ -42,11 +40,11 @@ struct udev_device {
        const char *sysnum;
        char *devnode;
        char *subsystem;
-       char **envp;
        char *driver;
        char *action;
        char *devpath_old;
        char *physdevpath;
+       char **envp;
        char *monitor_buf;
        size_t monitor_buf_len;
        struct udev_list_node devlinks_list;
@@ -594,8 +592,6 @@ struct udev_device *udev_device_ref(struct udev_device *udev_device)
  **/
 void udev_device_unref(struct udev_device *udev_device)
 {
-       unsigned int i;
-
        if (udev_device == NULL)
                return;
        udev_device->refcount--;
@@ -614,11 +610,7 @@ void udev_device_unref(struct udev_device *udev_device)
        free(udev_device->devpath_old);
        free(udev_device->physdevpath);
        udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
-       if (udev_device->envp != NULL) {
-               for (i = 0; i < ENVP_SIZE && udev_device->envp[i] != NULL; i++)
-                       free(udev_device->envp[i]);
-               free(udev_device->envp);
-       }
+       free(udev_device->envp);
        free(udev_device->monitor_buf);
        info(udev_device->udev, "udev_device: %p released\n", udev_device);
        free(udev_device);
@@ -986,7 +978,6 @@ int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink
 
 struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device, const char *key, const char *value)
 {
-       udev_device->monitor_buf_len = 0;
        udev_device->envp_uptodate = 0;
        if (value == NULL) {
                struct udev_list_entry *list_entry;
@@ -1016,83 +1007,88 @@ struct udev_list_entry *udev_device_add_property_from_string(struct udev_device
        return udev_device_add_property(udev_device, name, val);
 }
 
-char **udev_device_get_properties_envp(struct udev_device *udev_device)
+#define ENVP_SIZE                      128
+#define MONITOR_BUF_SIZE               4096
+static int update_envp_monitor_buf(struct udev_device *udev_device)
 {
-       if (!udev_device->envp_uptodate) {
-               unsigned int i;
-               struct udev_list_entry *list_entry;
+       const char *action;
+       struct udev_list_entry *list_entry;
+       size_t bufpos;
+       size_t len;
+       unsigned int i;
 
-               if (udev_device->envp != NULL) {
-                       for (i = 0; i < ENVP_SIZE && udev_device->envp[i] != NULL; i++)
-                               free(udev_device->envp[i]);
-               } else {
-                       udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
-               }
+       /* monitor buffer of property strings */
+       free(udev_device->monitor_buf);
+       udev_device->monitor_buf_len = 0;
+       udev_device->monitor_buf = malloc(MONITOR_BUF_SIZE);
+       if (udev_device->monitor_buf == NULL)
+               return -ENOMEM;
 
-               i = 0;
-               udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
-                       asprintf(&udev_device->envp[i++], "%s=%s",
-                                udev_list_entry_get_name(list_entry),
-                                udev_list_entry_get_value(list_entry));
-                       if (i+1 >= ENVP_SIZE)
-                               break;
-               }
-               udev_device->envp[i] = NULL;
-               info(udev_device->udev, "constructed envp from %u properties\n", i);
-               udev_device->envp_uptodate = 1;
-       }
-       return udev_device->envp;
-}
+       /* envp array, strings will point into monitor buffer */
+       free(udev_device->envp);
+       udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
+       if (udev_device->envp == NULL)
+               return -ENOMEM;
 
-#define MONITOR_BUF_SIZE               4096
-ssize_t udev_device_get_properties_monitor_buf(struct udev_device *udev_device, const char **buf)
-{
-       if (udev_device->monitor_buf_len == 0) {
-               const char *action;
-               struct udev_list_entry *list_entry;
-               size_t bufpos;
-               size_t len;
+       /* header <action>@<devpath> */
+       action = udev_device_get_action(udev_device);
+       if (action == NULL)
+               return -EINVAL;
+       bufpos = util_strlcpy(udev_device->monitor_buf, action, MONITOR_BUF_SIZE);
+       len = util_strlcpy(&udev_device->monitor_buf[bufpos], "@", MONITOR_BUF_SIZE-bufpos);
+       if (len >= MONITOR_BUF_SIZE-bufpos)
+               return -EINVAL;
+       bufpos += len;
+       len = util_strlcpy(&udev_device->monitor_buf[bufpos],
+                          udev_device_get_devpath(udev_device),
+                          MONITOR_BUF_SIZE-bufpos);
+       if (len+1 >= MONITOR_BUF_SIZE-bufpos)
+               return -EINVAL;
+       bufpos += len+1;
 
-               free(udev_device->monitor_buf);
-               udev_device->monitor_buf = malloc(MONITOR_BUF_SIZE);
-               if (udev_device->monitor_buf == NULL)
-                       return -ENOMEM;
+       i = 0;
+       udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
+               /* add string to envp array */
+               udev_device->envp[i++] = &udev_device->monitor_buf[bufpos];
+               if (i+1 >= ENVP_SIZE)
+                       return -EINVAL;
 
-               /* header <action>@<devpath> */
-               action = udev_device_get_action(udev_device);
-               if (action == NULL)
+               /* add property string to monitor buffer */
+               len = util_strlcpy(&udev_device->monitor_buf[bufpos],
+                                  udev_list_entry_get_name(list_entry), MONITOR_BUF_SIZE-bufpos);
+               if (len >= MONITOR_BUF_SIZE-bufpos)
                        return -EINVAL;
-               bufpos = util_strlcpy(udev_device->monitor_buf, action, MONITOR_BUF_SIZE);
-               len = util_strlcpy(&udev_device->monitor_buf[bufpos], "@", MONITOR_BUF_SIZE-bufpos);
+               bufpos += len;
+               len = util_strlcpy(&udev_device->monitor_buf[bufpos], "=", MONITOR_BUF_SIZE-bufpos);
                if (len >= MONITOR_BUF_SIZE-bufpos)
                        return -EINVAL;
                bufpos += len;
-               len = util_strlcpy(&udev_device->monitor_buf[bufpos],
-                                  udev_device_get_devpath(udev_device),
+               len = util_strlcpy(&udev_device->monitor_buf[bufpos], udev_list_entry_get_value(list_entry),
                                   MONITOR_BUF_SIZE-bufpos);
                if (len+1 >= MONITOR_BUF_SIZE-bufpos)
                        return -EINVAL;
                bufpos += len+1;
-
-               /* property strings */
-               udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
-                       len = util_strlcpy(&udev_device->monitor_buf[bufpos],
-                                          udev_list_entry_get_name(list_entry), MONITOR_BUF_SIZE-bufpos);
-                       if (len >= MONITOR_BUF_SIZE-bufpos)
-                               return -EINVAL;
-                       bufpos += len;
-                       len = util_strlcpy(&udev_device->monitor_buf[bufpos], "=", MONITOR_BUF_SIZE-bufpos);
-                       if (len >= MONITOR_BUF_SIZE-bufpos)
-                               return -EINVAL;
-                       bufpos += len;
-                       len = util_strlcpy(&udev_device->monitor_buf[bufpos], udev_list_entry_get_value(list_entry),
-                                          MONITOR_BUF_SIZE-bufpos);
-                       if (len+1 >= MONITOR_BUF_SIZE-bufpos)
-                               return -EINVAL;
-                       bufpos += len+1;
-               }
-               udev_device->monitor_buf_len = bufpos;
        }
+       udev_device->envp[i] = NULL;
+       udev_device->monitor_buf_len = bufpos;
+       udev_device->envp_uptodate = 1;
+       info(udev_device->udev, "filled envp/monitor buffer, %u properties, %zu bytes\n", i, bufpos);
+       return 0;
+}
+
+char **udev_device_get_properties_envp(struct udev_device *udev_device)
+{
+       if (!udev_device->envp_uptodate)
+               if (update_envp_monitor_buf(udev_device) < 32)
+                       return NULL;
+       return udev_device->envp;
+}
+
+ssize_t udev_device_get_properties_monitor_buf(struct udev_device *udev_device, const char **buf)
+{
+       if (!udev_device->envp_uptodate)
+               if (update_envp_monitor_buf(udev_device) < 32)
+                       return -EINVAL;
        *buf = udev_device->monitor_buf;
        return udev_device->monitor_buf_len;
 }