[PATCH] replace fgets() with mmap() and introduce udev_lib.[hc]

Here we replace the various fgets() with a mmap() call for the config
file reading, due to the reported performance problems with klibc.

Thanks to Patrick's testing, it makes a very small, close to nothing
speed gain for libc users, but a 6 times speed increase for klibc users
with a 1000 line config file.

I've created a udev_lib.[hc] for this and also moved all the generic
stuff from udev.h in there and uninlined the functions.

1 files changed, 21 insertions, 11 deletions

diff --git a/udev_config.c b/udev_config.c
index e2031dc64d..57a512d711 100644
--- a/udev_config.c
+++ b/udev_config.c
@@ -34,6 +34,7 @@
 
 #include "libsysfs/sysfs/libsysfs.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "logging.h"
 #include "namedev.h"
@@ -131,12 +132,14 @@ static int parse_config_file(void)
 	char *temp;
 	char *variable;
 	char *value;
-	FILE *fd;
-	int lineno = 0;
+	char *buf;
+	size_t bufsize;
+	size_t cur;
+	size_t count;
+	int lineno;
 	int retval = 0;
-	
-	fd = fopen(udev_config_filename, "r");
-	if (fd != NULL) {
+
+	if (file_map(udev_config_filename, &buf, &bufsize) == 0) {
 		dbg("reading '%s' as config file", udev_config_filename);
 	} else {
 		dbg("can't open '%s' as config file", udev_config_filename);
@@ -144,13 +147,20 @@ static int parse_config_file(void)
 	}
 
 	/* loop through the whole file */
+	lineno = 0;
+	cur = 0;
 	while (1) {
-		/* get a line */
-		temp = fgets(line, sizeof(line), fd);
-		if (temp == NULL)
-			goto exit;
+		count = buf_get_line(buf, bufsize, cur);
+
+		strncpy(line, buf + cur, count);
+		line[count] = '\0';
+		temp = line;
 		lineno++;
 
+		cur += count+1;
+		if (cur > bufsize)
+			break;
+
 		dbg_parse("read '%s'", temp);
 
 		/* eat the whitespace at the beginning of the line */
@@ -182,8 +192,8 @@ static int parse_config_file(void)
 	}
 	dbg_parse("%s:%d:%Zd: error parsing '%s'", udev_config_filename,
 		  lineno, temp - line, temp);
-exit:
-	fclose(fd);
+
+	file_unmap(buf, bufsize);
 	return retval;
 }