Definition and implementation of new guestfs_read_lines API call.

daemon/file.c

@@ -18,7 +18,7 @@
 
 #include <config.h>
 
-#define _GNU_SOURCE		/* for futimens(2) */
+#define _GNU_SOURCE		/* for futimens(2) and getline(3) */
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -128,3 +128,55 @@ do_cat (const char *path)
 
   return buf;			/* caller will free */
 }
+
+char **
+do_read_lines (const char *path)
+{
+  char **r = NULL;
+  int size = 0, alloc = 0;
+  FILE *fp;
+  char *line = NULL;
+  size_t len = 0;
+  ssize_t n;
+
+  NEED_ROOT (NULL);
+  ABS_PATH (path, NULL);
+
+  CHROOT_IN;
+  fp = fopen (path, "r");
+  CHROOT_OUT;
+
+  if (!fp) {
+    reply_with_perror ("fopen: %s", path);
+    return NULL;
+  }
+
+  while ((n = getline (&line, &len, fp)) != -1) {
+    /* Remove either LF or CRLF. */
+    if (n >= 2 && line[n-2] == '\r' && line[n-1] == '\n')
+      line[n-2] = '\0';
+    else if (n >= 1 && line[n-1] == '\n')
+      line[n-1] = '\0';
+
+    if (add_string (&r, &size, &alloc, line) == -1) {
+      free (line);
+      fclose (fp);
+      return NULL;
+    }
+  }
+
+  free (line);
+
+  if (add_string (&r, &size, &alloc, NULL) == -1) {
+    fclose (fp);
+    return NULL;
+  }
+
+  if (fclose (fp) == EOF) {
+    reply_with_perror ("fclose: %s", path);
+    free_strings (r);
+    return NULL;
+  }
+
+  return r;
+}

src/generator.ml

@@ -310,6 +310,19 @@ of the L<vgs(8)> command.  The \"full\" version includes all fields.");
    "\
 List all the logical volumes detected.  This is the equivalent
 of the L<lvs(8)> command.  The \"full\" version includes all fields.");
+
+  ("read_lines", (RStringList "lines", P1 (String "path")), 15, [],
+   "read file as lines",
+   "\
+Return the contents of the file named C<path>.
+
+The file contents are returned as a list of lines.  Trailing
+C<LF> and C<CRLF> character sequences are I<not> returned.
+
+Note that this function cannot correctly handle binary files
+(specifically, files containing C<\\0> character which is treated
+as end of line).  For those you need to use the C<guestfs_read_file>
+function which has a more complex interface.");
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions