utils: add {un,}map_file to read an entire file

This wraps the current mmap call and adds a fallback implementation for
systems which do not have mmap (e.g. mingw).

Signed-off-by: Ran Benita <ran234@gmail.com>

3 files changed, 122 insertions, 23 deletions

diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..a00b04e
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright © 2013 Ran Benita <ran234@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "utils.h"
+
+#ifdef HAVE_MMAP
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+bool
+map_file(FILE *file, const char **string_out, size_t *size_out)
+{
+    struct stat stat_buf;
+    const int fd = fileno(file);
+    char *string;
+
+    /* Make sure to keep the errno on failure! */
+
+    if (fstat(fd, &stat_buf) != 0)
+        return false;
+
+    string = mmap(NULL, stat_buf.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    if (string == MAP_FAILED)
+        return false;
+
+    *string_out = string;
+    *size_out = stat_buf.st_size;
+    return true;
+}
+
+void
+unmap_file(const char *str, size_t size)
+{
+    munmap(UNCONSTIFY(str), size);
+}
+
+#else
+
+bool
+map_file(FILE *file, const char **string_out, size_t *size_out)
+{
+    long ret;
+    size_t ret_s;
+    char *string;
+    size_t size;
+
+    /* Make sure to keep the errno on failure! */
+
+    ret = fseek(file, 0, SEEK_END);
+    if (ret != 0)
+        return false;
+
+    ret = ftell(file);
+    if (ret < 0)
+        return false;
+    size = (size_t) ret;
+
+    ret = fseek(file, 0, SEEK_SET);
+    if (ret < 0)
+        return false;
+
+    string = malloc(size);
+    if (!string)
+        return false;
+
+    ret_s = fread(string, 1, size, file);
+    if (ret_s < size) {
+        free(string);
+        return false;
+    }
+
+    *string_out = string;
+    *size_out = size;
+    return true;
+}
+
+void
+unmap_file(const char *str, size_t size)
+{
+    free(UNCONSTIFY(str));
+}
+
+#endif
diff --git a/src/utils.h b/src/utils.h
index b4daadd..160bc42 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -24,8 +24,10 @@
 #ifndef UTILS_H
 #define UTILS_H 1
 
+#include <errno.h>
 #include <inttypes.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <string.h>
 #include <strings.h>
 
@@ -91,6 +93,12 @@ memdup(const void *mem, size_t nmemb, size_t size)
     return p;
 }
 
+bool
+map_file(FILE *file, const char **string_out, size_t *size_out);
+
+void
+unmap_file(const char *str, size_t size);
+
 #define ARRAY_SIZE(arr) ((sizeof(arr) / sizeof(*(arr))))
 
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
diff --git a/src/xkbcomp/rules.c b/src/xkbcomp/rules.c
index ec4a7aa..a31aad7 100644
--- a/src/xkbcomp/rules.c
+++ b/src/xkbcomp/rules.c
@@ -47,13 +47,6 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
-#include <ctype.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
 #include "xkbcomp-priv.h"
 #include "rules.h"
 #include "include.h"
@@ -1099,36 +1092,27 @@ xkb_components_from_rules(struct xkb_context *ctx,
     bool ret = false;
     FILE *file;
     char *path;
-    int fd;
-    struct stat stat_buf;
-    char *string;
+    const char *string;
+    size_t size;
     struct matcher *matcher;
 
     file = FindFileInXkbPath(ctx, rmlvo->rules, FILE_TYPE_RULES, &path);
     if (!file)
         goto err_out;
 
-    fd = fileno(file);
-
-    if (fstat(fd, &stat_buf) != 0) {
-        log_err(ctx, "Couldn't stat rules file\n");
-        goto err_file;
-    }
-
-    string = mmap(NULL, stat_buf.st_size, PROT_READ, MAP_SHARED, fd, 0);
-    if (string == MAP_FAILED) {
-        log_err(ctx, "Couldn't mmap rules file (%lld bytes)\n",
-                (long long) stat_buf.st_size);
+    ret = map_file(file, &string, &size);
+    if (!ret) {
+        log_err(ctx, "Couldn't read rules file: %s\n", strerror(errno));
         goto err_file;
     }
 
     matcher = matcher_new(ctx, rmlvo);
-    ret = matcher_match(matcher, string, stat_buf.st_size, rmlvo->rules, out);
+    ret = matcher_match(matcher, string, size, rmlvo->rules, out);
     if (!ret)
         log_err(ctx, "No components returned from XKB rules \"%s\"\n", path);
     matcher_free(matcher);
 
-    munmap(string, stat_buf.st_size);
+    unmap_file(string, size);
 err_file:
     free(path);
     fclose(file);