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-rw-r--r--src/util/os_file.c62
1 files changed, 20 insertions, 42 deletions
diff --git a/src/util/os_file.c b/src/util/os_file.c
index ee34a75a2e0..246fd32fdf6 100644
--- a/src/util/os_file.c
+++ b/src/util/os_file.c
@@ -38,11 +38,29 @@ readN(int fd, char *buf, size_t len)
return total ? total : err;
}
-static char *
-read_grow(int fd)
+char *
+os_read_file(const char *filename)
{
+ /* Note that this also serves as a slight margin to avoid a 2x grow when
+ * the file is just a few bytes larger when we read it than when we
+ * fstat'ed it.
+ * The string's NULL terminator is also included in here.
+ */
size_t len = 64;
+ int fd = open(filename, O_RDONLY);
+ if (fd == -1) {
+ /* errno set by open() */
+ return NULL;
+ }
+
+ /* Pre-allocate a buffer at least the size of the file if we can read
+ * that information.
+ */
+ struct stat stat;
+ if (fstat(fd, &stat) == 0)
+ len += stat.st_size;
+
char *buf = malloc(len);
if (!buf) {
close(fd);
@@ -77,46 +95,6 @@ read_grow(int fd)
return buf;
}
-char *
-os_read_file(const char *filename)
-{
- size_t len = 0;
-
- int fd = open(filename, O_RDONLY);
- if (fd == -1) {
- /* errno set by open() */
- return NULL;
- }
-
- struct stat stat;
- if (fstat(fd, &stat) == 0)
- len = stat.st_size;
-
- if (!len)
- return read_grow(fd);
-
- /* add NULL terminator */
- len++;
-
- char *buf = malloc(len);
- if (!buf) {
- close(fd);
- errno = -ENOMEM;
- return NULL;
- }
-
- ssize_t read = readN(fd, buf, len - 1);
-
- close(fd);
-
- if (read == -1)
- return NULL;
-
- buf[read] = '\0';
-
- return buf;
-}
-
#else
char *