write: Improve help text of --writer.

[paraslash.git] / net.c

diff --git a/net.c b/net.c
index 9698e427868e212646f682d9b8dc2d7e8f6235ae..1b142a3cd4a25b87fe2e31c86caaf32e4be5f51e 100644 (file)
--- a/net.c
+++ b/net.c
@@ -6,11 +6,7 @@
 
 /** \file net.c Networking-related helper functions. */
 
-/*
- * Since glibc 2.8, the _GNU_SOURCE feature test macro must be defined in order
- * to obtain the definition of the ucred structure.
- */
-#define _GNU_SOURCE
+#include "para.h"
 
 #include <netinet/in.h>
 #include <arpa/inet.h>
@@ -32,7 +28,6 @@
 
 #include <regex.h>
 
-#include "para.h"
 #include "error.h"
 #include "net.h"
 #include "string.h"
@@ -834,13 +829,14 @@ int dccp_available_ccids(uint8_t **ccid_array)
  * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
  * than \p UNIX_PATH_MAX.
  */
-static int init_unix_addr(struct sockaddr_un *u, const char *name)
+static int init_unix_addr(struct sockaddr_un *u, const char *name,
+               bool abstract)
 {
-       if (strlen(name) >= UNIX_PATH_MAX)
+       if (strlen(name) + abstract >= UNIX_PATH_MAX)
                return -E_NAME_TOO_LONG;
        memset(u->sun_path, 0, UNIX_PATH_MAX);
        u->sun_family = PF_UNIX;
-       strcpy(u->sun_path, name);
+       strcpy(u->sun_path + abstract, name);
        return 1;
 }
 
@@ -855,6 +851,10 @@ static int init_unix_addr(struct sockaddr_un *u, const char *name)
  * nonblocking mode and listen(2) is called to prepare the socket for
  * accepting incoming connection requests.
  *
+ * If mode is zero, an abstract socket (a non-portable Linux extension) is
+ * created. In this case the socket name has no connection with filesystem
+ * pathnames.
+ *
  * \return The file descriptor on success, negative error code on failure.
  *
  * \sa socket(2), \sa bind(2), \sa chmod(2), listen(2), unix(7).
@@ -863,8 +863,9 @@ int create_local_socket(const char *name, mode_t mode)
 {
        struct sockaddr_un unix_addr;
        int fd, ret;
+       bool abstract = mode == 0;
 
-       ret = init_unix_addr(&unix_addr, name);
+       ret = init_unix_addr(&unix_addr, name, abstract);
        if (ret < 0)
                return ret;
        ret = socket(PF_UNIX, SOCK_STREAM, 0);
@@ -874,14 +875,16 @@ int create_local_socket(const char *name, mode_t mode)
        ret = mark_fd_nonblocking(fd);
        if (ret < 0)
                goto err;
-       ret = bind(fd, (struct sockaddr *)&unix_addr, UNIX_PATH_MAX);
+       ret = bind(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr));
        if (ret < 0) {
                ret = -ERRNO_TO_PARA_ERROR(errno);
                goto err;
        }
-       ret = -E_CHMOD;
-       if (chmod(name, mode) < 0)
-               goto err;
+       if (!abstract) {
+               ret = -E_CHMOD;
+               if (chmod(name, mode) < 0)
+                       goto err;
+       }
        if (listen(fd , 5) < 0) {
                ret = -ERRNO_TO_PARA_ERROR(errno);
                goto err;
@@ -911,17 +914,22 @@ int connect_local_socket(const char *name)
        int fd, ret;
 
        PARA_DEBUG_LOG("connecting to %s\n", name);
-       ret = init_unix_addr(&unix_addr, name);
-       if (ret < 0)
-               return ret;
        fd = socket(PF_UNIX, SOCK_STREAM, 0);
        if (fd < 0)
                return -ERRNO_TO_PARA_ERROR(errno);
-       if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
-               ret = -ERRNO_TO_PARA_ERROR(errno);
+       /* first try (linux-only) abstract socket */
+       ret = init_unix_addr(&unix_addr, name, true);
+       if (ret < 0)
                goto err;
-       }
-       return fd;
+       if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1)
+               return fd;
+       /* next try pathname socket */
+       ret = init_unix_addr(&unix_addr, name, false);
+       if (ret < 0)
+               goto err;
+       if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1)
+               return fd;
+       ret = -ERRNO_TO_PARA_ERROR(errno);
 err:
        close(fd);
        return ret;
@@ -1005,7 +1013,7 @@ static void dispose_fds(int *fds, unsigned num)
  */
 int recv_cred_buffer(int fd, char *buf, size_t size)
 {
-       char control[255];
+       char control[255] __a_aligned(8);
        struct msghdr msg;
        struct cmsghdr *cmsg;
        struct iovec iov;