Add sftp_extension_supported() function.

include/libssh/sftp.h

@@ -261,6 +261,26 @@ LIBSSH_API const char *sftp_extensions_get_name(SFTP_SESSION *sftp, unsigned int
  */
 LIBSSH_API const char *sftp_extensions_get_data(SFTP_SESSION *sftp, unsigned int index);
 
+/**
+ * @brief Check if the given extension is supported.
+ *
+ * @param  sftp         The sftp session to use.
+ *
+ * @param  name         The name of the extension.
+ *
+ * @param  data         The data of the extension.
+ *
+ * @return 1 if supported, 0 if not.
+ *
+ * Example:
+ *
+ * @code
+ * sftp_extension_supported(sftp, "statvfs@openssh.com", "2");
+ * @endcode
+ */
+LIBSSH_API int sftp_extension_supported(SFTP_SESSION *sftp, const char *name,
+    const char *data);
+
 /**
  * @brief Open a directory used to obtain directory entries.
  *

libssh/sftp.c

@@ -45,12 +45,6 @@
 #define sftp_leave_function() _leave_function(sftp->channel->session)
 
 struct sftp_ext_struct {
-  int rename_openssh;
-  int rename_openssh_version;
-  int statvfs_openssh;
-  int statvfs_openssh_version;
-  int fstatvfs_openssh;
-  int fstatvfs_openssh_version;
   unsigned int count;
   char **name;
   char **data;
@@ -536,17 +530,6 @@ int sftp_init(SFTP_SESSION *sftp) {
         "SFTP server extension: %s, version: %s",
         ext_name, ext_data);
 
-    if (strcmp(ext_name, "posix-rename@openssh.com") == 0) {
-      sftp->ext->rename_openssh = 1;
-      sftp->ext->rename_openssh_version = strtol(ext_data, (char **) NULL, 10);
-    } else if (strcmp(ext_name, "statvfs@openssh.com") == 0) {
-      sftp->ext->statvfs_openssh = 1;
-      sftp->ext->statvfs_openssh_version = strtol(ext_data, (char **) NULL, 10);
-    } else if (strcmp(ext_name, "fstatvfs@openssh.com") == 0) {
-      sftp->ext->fstatvfs_openssh = 1;
-      sftp->ext->fstatvfs_openssh_version = strtol(ext_data, (char **) NULL, 10);
-    }
-
     count++;
     tmp = realloc(sftp->ext->name, count * sizeof(char *));
     if (tmp == NULL) {
@@ -619,6 +602,21 @@ const char *sftp_extensions_get_data(SFTP_SESSION *sftp, unsigned int index) {
   return sftp->ext->data[index];
 }
 
+int sftp_extension_supported(SFTP_SESSION *sftp, const char *name,
+    const char *data) {
+  int i, n;
+
+  n = sftp_extensions_get_count(sftp);
+  for (i = 0; i < n; i++) {
+    if (strcmp(sftp_extensions_get_name(sftp, i), name) == 0 &&
+        strcmp(sftp_extensions_get_data(sftp, i), data) == 0) {
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
 static REQUEST_QUEUE *request_queue_new(SFTP_MESSAGE *msg) {
   REQUEST_QUEUE *queue = NULL;
 

sample.c

@@ -327,67 +327,69 @@ void do_sftp(SSH_SESSION *session){
 
     sftp_unlink(sftp_session, "/tmp/sftp_symlink_test");
 
-    sftpstatvfs = sftp_statvfs(sftp_session, "/tmp");
+    if (sftp_extension_supported(sftp_session, "statvfs@openssh.com", "2")) {
-    if (sftpstatvfs == NULL) {
+      sftpstatvfs = sftp_statvfs(sftp_session, "/tmp");
-      fprintf(stderr, "statvfs failed (%s)\n", ssh_get_error(session));
+      if (sftpstatvfs == NULL) {
-      return;
+        fprintf(stderr, "statvfs failed (%s)\n", ssh_get_error(session));
+        return;
+      }
+
+      printf("sftp statvfs:\n"
+          "\tfile system block size: %llu\n"
+          "\tfundamental fs block size: %llu\n"
+          "\tnumber of blocks (unit f_frsize): %llu\n"
+          "\tfree blocks in file system: %llu\n"
+          "\tfree blocks for non-root: %llu\n"
+          "\ttotal file inodes: %llu\n"
+          "\tfree file inodes: %llu\n"
+          "\tfree file inodes for to non-root: %llu\n"
+          "\tfile system id: %llu\n"
+          "\tbit mask of f_flag values: %llu\n"
+          "\tmaximum filename length: %llu\n",
+          sftpstatvfs->f_bsize,
+          sftpstatvfs->f_frsize,
+          sftpstatvfs->f_blocks,
+          sftpstatvfs->f_bfree,
+          sftpstatvfs->f_bavail,
+          sftpstatvfs->f_files,
+          sftpstatvfs->f_ffree,
+          sftpstatvfs->f_favail,
+          sftpstatvfs->f_fsid,
+          sftpstatvfs->f_flag,
+          sftpstatvfs->f_namemax);
+
+      sftp_statvfs_free(sftpstatvfs);
+
+      if (statvfs("/tmp", &sysstatvfs) < 0) {
+        fprintf(stderr, "statvfs failed (%s)\n", strerror(errno));
+        return;
+      }
+
+      printf("sys statvfs:\n"
+          "\tfile system block size: %llu\n"
+          "\tfundamental fs block size: %llu\n"
+          "\tnumber of blocks (unit f_frsize): %llu\n"
+          "\tfree blocks in file system: %llu\n"
+          "\tfree blocks for non-root: %llu\n"
+          "\ttotal file inodes: %llu\n"
+          "\tfree file inodes: %llu\n"
+          "\tfree file inodes for to non-root: %llu\n"
+          "\tfile system id: %llu\n"
+          "\tbit mask of f_flag values: %llu\n"
+          "\tmaximum filename length: %llu\n",
+          sysstatvfs.f_bsize,
+          sysstatvfs.f_frsize,
+          sysstatvfs.f_blocks,
+          sysstatvfs.f_bfree,
+          sysstatvfs.f_bavail,
+          sysstatvfs.f_files,
+          sysstatvfs.f_ffree,
+          sysstatvfs.f_favail,
+          sysstatvfs.f_fsid,
+          sysstatvfs.f_flag,
+          sysstatvfs.f_namemax);
     }
 
-    printf("sftp statvfs:\n"
-        "\tfile system block size: %llu\n"
-        "\tfundamental fs block size: %llu\n"
-        "\tnumber of blocks (unit f_frsize): %llu\n"
-        "\tfree blocks in file system: %llu\n"
-        "\tfree blocks for non-root: %llu\n"
-        "\ttotal file inodes: %llu\n"
-        "\tfree file inodes: %llu\n"
-        "\tfree file inodes for to non-root: %llu\n"
-        "\tfile system id: %llu\n"
-        "\tbit mask of f_flag values: %llu\n"
-        "\tmaximum filename length: %llu\n",
-        sftpstatvfs->f_bsize,
-        sftpstatvfs->f_frsize,
-        sftpstatvfs->f_blocks,
-        sftpstatvfs->f_bfree,
-        sftpstatvfs->f_bavail,
-        sftpstatvfs->f_files,
-        sftpstatvfs->f_ffree,
-        sftpstatvfs->f_favail,
-        sftpstatvfs->f_fsid,
-        sftpstatvfs->f_flag,
-        sftpstatvfs->f_namemax);
-
-    sftp_statvfs_free(sftpstatvfs);
-
-    if (statvfs("/tmp", &sysstatvfs) < 0) {
-      fprintf(stderr, "statvfs failed (%s)\n", strerror(errno));
-      return;
-    }
-
-    printf("sys statvfs:\n"
-        "\tfile system block size: %llu\n"
-        "\tfundamental fs block size: %llu\n"
-        "\tnumber of blocks (unit f_frsize): %llu\n"
-        "\tfree blocks in file system: %llu\n"
-        "\tfree blocks for non-root: %llu\n"
-        "\ttotal file inodes: %llu\n"
-        "\tfree file inodes: %llu\n"
-        "\tfree file inodes for to non-root: %llu\n"
-        "\tfile system id: %llu\n"
-        "\tbit mask of f_flag values: %llu\n"
-        "\tmaximum filename length: %llu\n",
-        sysstatvfs.f_bsize,
-        sysstatvfs.f_frsize,
-        sysstatvfs.f_blocks,
-        sysstatvfs.f_bfree,
-        sysstatvfs.f_bavail,
-        sysstatvfs.f_files,
-        sysstatvfs.f_ffree,
-        sysstatvfs.f_favail,
-        sysstatvfs.f_fsid,
-        sysstatvfs.f_flag,
-        sysstatvfs.f_namemax);
-
     /* the connection is made */
     /* opening a directory */
     dir=sftp_opendir(sftp_session,"./");