Re: [PATCH] cleanup udevstart

[Kay Sievers <kay.sievers@vrfy.org>]

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On Mon, Mar 15, 2004 at 10:22:02PM +0100, Olaf Hering wrote:
>  On Tue, Mar 02, Greg KH wrote:
> 
> > # /usr/bin/time /sbin/udevstart 
> > Command exited with non-zero status 22
> > 0.19user 0.67system 0:01.04elapsed 83%CPU (0avgtext+0avgdata 0maxresident)k
> > 0inputs+0outputs (2major+6065minor)pagefaults 0swaps
> > 
> > 1 second to populate a full /dev while the system is under a very heavy
> > load is pretty good I think :)
> 
> 
> Yeah, I was using the klibc version, that makes it slower due to the
> clever fgets implementation.

Hey, better try to fix it :)
You may try this one.

thanks,
Kay

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===== namedev_parse.c 1.32 vs edited =====
--- 1.32/namedev_parse.c	Fri Mar 12 17:43:30 2004
+++ edited/namedev_parse.c	Tue Mar 16 02:16:35 2004
@@ -36,6 +36,7 @@
 #include <sys/stat.h>
 #include <dirent.h>
 #include <errno.h>
+#include <sys/mman.h>
 
 #include "udev.h"
 #include "logging.h"
@@ -145,6 +146,47 @@
 	return NULL;
 }
 
+static int file_map(const char *filename, char **buf, size_t *bufsize)
+{
+	struct stat stats;
+	int fd;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		dbg("can't open '%s'", filename);
+		return -1;
+	}
+
+	if (fstat(fd, &stats) < 0) {
+		dbg("error stating '%s'", filename);
+		return -1;
+	}
+
+	*buf = mmap(NULL, stats.st_size, PROT_READ, MAP_SHARED, fd, 0);
+	if (*buf == MAP_FAILED) {
+		dbg("error mapping file '%s'", filename);
+		return -1;
+	}
+	*bufsize = stats.st_size;
+
+	return 0;
+}
+
+static void file_unmap(char *buf, size_t bufsize)
+{
+	munmap(buf, bufsize);
+}
+
+
+static size_t buf_get_line(char *buf, size_t buflen, size_t cur)
+{
+	size_t count = 0;
+
+	for (count = cur; count < buflen && buf[count] != '\n'; count++);
+
+	return count - cur;
+}
+
 static int namedev_parse_rules(char *filename)
 {
 	char line[255];
@@ -153,27 +195,38 @@
 	char *temp2;
 	char *temp3;
 	char *attr;
-	FILE *fd;
+	char *buf;
+	size_t bufsize;
+	size_t cur;
+	size_t count;
 	int program_given = 0;
 	int retval = 0;
 	struct config_device dev;
 
-	fd = fopen(filename, "r");
-	if (fd != NULL) {
+	if (file_map(filename, &buf, &bufsize) == 0) {
 		dbg("reading '%s' as rules file", filename);
 	} else {
 		dbg("can't open '%s' as a rules file", filename);
 		return -ENODEV;
 	}
 
+	dbg("bufsize %i", bufsize);
+
 	/* loop through the whole file */
+	cur = 0;
 	lineno = 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 */
@@ -312,7 +365,7 @@
 		}
 	}
 exit:
-	fclose(fd);
+	file_unmap(buf, bufsize);
 	return retval;
 }