[Stgt-devel] VTL patch, take 2

[FUJITA Tomonori]

From: "Mark Harvey" <markh794 at gmail.com>
Subject: [Stgt-devel] VTL patch, take 2
Date: Fri, 13 Apr 2007 07:28:04 +1000

> SSC / SMC patches to SCSI Tgt code.
> 
> It is based from git commit :
>    ================================
> commit 47e15c234ca298d31b1709db592eef9db4bce0ca
> Author: Albert Pauw <albert.pauw at gmail.com>
> Date:   Sat Apr 7 17:31:54 2007 +0900
> 
>     some shortcut options missing from tgtadm
> 
>     Signed-off-by: Albert Pauw <albert.pauw at gmail.com>
>    ================================
> 
> 
> Additions from last patch include :
>  - Updated syntax to add/configure limited set of SMC / SSC parameters
>  - Start implementing structures for MODE SELECT / MODE SENSE op codes
>  - Start implementing structures for LOG SELECT / LOG SENSE op codes
> 
>  - SMC module includes:
>    Allocation of MODE pages and initialization to default values.
>    Ability to change Element Address Assignment
> 
> 
> 
> This is a work-in-progress and is being posted as an example of
> where/how I'm attempting to implement a VTL.
> 
> I need to update command parameter passing to recommended use of
> "--params ....."

I've attached a parser patch (taken from Linux kernel). See
tgt_device_update() about how it works if you are not familiar with
the Linux parser. I think that it works for you. And if so, I'll merge
this patch shortly (though I need to change it slightly).


> Next step is to implement the SCSI MODE SENSE op code so I can
> actually test what is being set is correct..
> 
> Note: in root of src is a 'tgt-setup' script which will (should)
> correctly configure the SSC & SMC modules

I think that it would be better to create a new directory for example
scripts.


diff --git a/usr/Makefile b/usr/Makefile
index 96535f9..2e299dc 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -45,7 +45,7 @@ CFLAGS += -Wall -g -O2 -Wstrict-prototyp
 
 PROGRAMS += tgtd tgtadm
 TGTD_OBJS += tgtd.o mgmt.o target.o spc.o sbc.o mmc.o osd.o spt.o scsi.o log.o \
-	driver.o util.o work.o
+	driver.o util.o work.o parser.o
 
 all: $(PROGRAMS)
 
diff --git a/usr/parser.c b/usr/parser.c
new file mode 100644
index 0000000..75fe12c
--- /dev/null
+++ b/usr/parser.c
@@ -0,0 +1,216 @@
+/*
+ * lib/parser.c - simple parser for mount, etc. options.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "parser.h"
+
+/**
+ * match_one: - Determines if a string matches a simple pattern
+ * @s: the string to examine for presense of the pattern
+ * @p: the string containing the pattern
+ * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
+ * locations.
+ *
+ * Description: Determines if the pattern @p is present in string @s. Can only
+ * match extremely simple token=arg style patterns. If the pattern is found,
+ * the location(s) of the arguments will be returned in the @args array.
+ */
+static int match_one(char *s, char *p, substring_t args[])
+{
+	char *meta;
+	int argc = 0;
+
+	if (!p)
+		return 1;
+
+	while(1) {
+		int len = -1;
+		meta = strchr(p, '%');
+		if (!meta)
+			return strcmp(p, s) == 0;
+
+		if (strncmp(p, s, meta-p))
+			return 0;
+
+		s += meta - p;
+		p = meta + 1;
+
+		if (isdigit(*p))
+			len = strtoul(p, &p, 10);
+		else if (*p == '%') {
+			if (*s++ != '%')
+				return 0;
+			p++;
+			continue;
+		}
+
+		if (argc >= MAX_OPT_ARGS)
+			return 0;
+
+		args[argc].from = s;
+		switch (*p++) {
+		case 's':
+			if (strlen(s) == 0)
+				return 0;
+			else if (len == -1 || len > strlen(s))
+				len = strlen(s);
+			args[argc].to = s + len;
+			break;
+		case 'd':
+			strtol(s, &args[argc].to, 0);
+			goto num;
+		case 'u':
+			strtoul(s, &args[argc].to, 0);
+			goto num;
+		case 'o':
+			strtoul(s, &args[argc].to, 8);
+			goto num;
+		case 'x':
+			strtoul(s, &args[argc].to, 16);
+		num:
+			if (args[argc].to == args[argc].from)
+				return 0;
+			break;
+		default:
+			return 0;
+		}
+		s = args[argc].to;
+		argc++;
+	}
+}
+
+/**
+ * match_token: - Find a token (and optional args) in a string
+ * @s: the string to examine for token/argument pairs
+ * @table: match_table_t describing the set of allowed option tokens and the
+ * arguments that may be associated with them. Must be terminated with a
+ * &struct match_token whose pattern is set to the NULL pointer.
+ * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
+ * locations.
+ *
+ * Description: Detects which if any of a set of token strings has been passed
+ * to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
+ * format identifiers which will be taken into account when matching the
+ * tokens, and whose locations will be returned in the @args array.
+ */
+int match_token(char *s, match_table_t table, substring_t args[])
+{
+	struct match_token *p;
+
+	for (p = table; !match_one(s, p->pattern, args) ; p++)
+		;
+
+	return p->token;
+}
+
+/**
+ * match_number: scan a number in the given base from a substring_t
+ * @s: substring to be scanned
+ * @result: resulting integer on success
+ * @base: base to use when converting string
+ *
+ * Description: Given a &substring_t and a base, attempts to parse the substring
+ * as a number in that base. On success, sets @result to the integer represented
+ * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
+ */
+static int match_number(substring_t *s, int *result, int base)
+{
+	char *endp;
+	char *buf;
+	int ret;
+
+	buf = malloc(s->to - s->from + 1);
+	if (!buf)
+		return -ENOMEM;
+	memcpy(buf, s->from, s->to - s->from);
+	buf[s->to - s->from] = '\0';
+	*result = strtol(buf, &endp, base);
+	ret = 0;
+	if (endp == buf)
+		ret = -EINVAL;
+	free(buf);
+	return ret;
+}
+
+/**
+ * match_int: - scan a decimal representation of an integer from a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting integer on success
+ *
+ * Description: Attempts to parse the &substring_t @s as a decimal integer. On
+ * success, sets @result to the integer represented by the string and returns 0.
+ * Returns either -ENOMEM or -EINVAL on failure.
+ */
+int match_int(substring_t *s, int *result)
+{
+	return match_number(s, result, 0);
+}
+
+/**
+ * match_octal: - scan an octal representation of an integer from a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting integer on success
+ *
+ * Description: Attempts to parse the &substring_t @s as an octal integer. On
+ * success, sets @result to the integer represented by the string and returns
+ * 0. Returns either -ENOMEM or -EINVAL on failure.
+ */
+int match_octal(substring_t *s, int *result)
+{
+	return match_number(s, result, 8);
+}
+
+/**
+ * match_hex: - scan a hex representation of an integer from a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting integer on success
+ *
+ * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
+ * On success, sets @result to the integer represented by the string and
+ * returns 0. Returns either -ENOMEM or -EINVAL on failure.
+ */
+int match_hex(substring_t *s, int *result)
+{
+	return match_number(s, result, 16);
+}
+
+/**
+ * match_strcpy: - copies the characters from a substring_t to a string
+ * @to: string to copy characters to.
+ * @s: &substring_t to copy
+ *
+ * Description: Copies the set of characters represented by the given
+ * &substring_t @s to the c-style string @to. Caller guarantees that @to is
+ * large enough to hold the characters of @s.
+ */
+void match_strcpy(char *to, substring_t *s)
+{
+	memcpy(to, s->from, s->to - s->from);
+	to[s->to - s->from] = '\0';
+}
+
+/**
+ * match_strdup: - allocate a new string with the contents of a substring_t
+ * @s: &substring_t to copy
+ *
+ * Description: Allocates and returns a string filled with the contents of
+ * the &substring_t @s. The caller is responsible for freeing the returned
+ * string with kfree().
+ */
+char *match_strdup(substring_t *s)
+{
+	char *p = malloc(s->to - s->from + 1);
+	if (p)
+		match_strcpy(p, s);
+	return p;
+}
diff --git a/usr/parser.h b/usr/parser.h
new file mode 100644
index 0000000..fa33328
--- /dev/null
+++ b/usr/parser.h
@@ -0,0 +1,33 @@
+/*
+ * linux/include/linux/parser.h
+ *
+ * Header for lib/parser.c
+ * Intended use of these functions is parsing filesystem argument lists,
+ * but could potentially be used anywhere else that simple option=arg
+ * parsing is required.
+ */
+
+
+/* associates an integer enumerator with a pattern string. */
+struct match_token {
+	int token;
+	char *pattern;
+};
+
+typedef struct match_token match_table_t[];
+
+/* Maximum number of arguments that match_token will find in a pattern */
+enum {MAX_OPT_ARGS = 3};
+
+/* Describe the location within a string of a substring */
+typedef struct {
+	char *from;
+	char *to;
+} substring_t;
+
+int match_token(char *, match_table_t table, substring_t args[]);
+int match_int(substring_t *, int *result);
+int match_octal(substring_t *, int *result);
+int match_hex(substring_t *, int *result);
+void match_strcpy(char *, substring_t *);
+char *match_strdup(substring_t *);
diff --git a/usr/target.c b/usr/target.c
index 1a9fe68..1510078 100644
--- a/usr/target.c
+++ b/usr/target.c
@@ -29,6 +29,7 @@ #include <unistd.h>
 #include <sys/socket.h>
 
 #include "list.h"
+#include "parser.h"
 #include "util.h"
 #include "tgtd.h"
 #include "driver.h"
@@ -338,9 +339,20 @@ int device_reserved(struct scsi_cmd *cmd
 	return -EBUSY;
 }
 
-int tgt_device_update(int tid, uint64_t dev_id, char *name)
+enum {
+	Opt_scsiid, Opt_scsisn, Opt_err,
+};
+
+static match_table_t tokens = {
+	{Opt_scsiid, "Scsi_id=%s"},
+	{Opt_scsisn, "Scsi_sn=%s"},
+	{Opt_err, NULL},
+};
+
+int tgt_device_update(int tid, uint64_t dev_id, char *params)
 {
 	int err = 0;
+	char *p;
 	struct target *target;
 	struct scsi_lu *lu;
 
@@ -354,12 +366,24 @@ int tgt_device_update(int tid, uint64_t
 		return TGTADM_NO_LUN;
 	}
 
-	if (!strncmp(name, "scsi_id=", 8))
-		memcpy(lu->scsi_id, name + 8, sizeof(lu->scsi_id) - 1);
-	else if (!strncmp(name, "scsi_sn=", 8))
-		memcpy(lu->scsi_sn, name + 8, sizeof(lu->scsi_sn) - 1);
-	else
-		err = TGTADM_INVALID_REQUEST;
+	while ((p = strsep(&params, ",")) != NULL) {
+		substring_t args[MAX_OPT_ARGS];
+		int token;
+		if (!*p)
+			continue;
+		token = match_token(p, tokens, args);
+
+		switch (token) {
+		case Opt_scsiid:
+			match_strcpy(lu->scsi_id, &args[0]);
+			break;
+		case Opt_scsisn:
+			match_strcpy(lu->scsi_sn, &args[0]);
+			break;
+		default:
+			err = TGTADM_INVALID_REQUEST;
+		}
+	}
 
 	return err;
 }