Patchwork [U-Boot,RFC,1/4] Groundwork for generalization of env interface

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Submitter Gerlando Falauto
Date Sept. 30, 2011, 12:04 p.m.
Message ID <1317384298-27025-2-git-send-email-gerlando.falauto@keymile.com>
Download mbox | patch
Permalink /patch/117129/
State Changes Requested
Headers show

Comments

Gerlando Falauto - Sept. 30, 2011, 12:04 p.m.
Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
---
 common/cmd_nvedit.c   |  150 ++++++++++++++++++++++++++++++-------------------
 common/env_common.c   |   15 ++++-
 include/environment.h |    2 +
 include/search.h      |   13 ++++
 lib/hashtable.c       |   48 ++++++++++++++++
 5 files changed, 169 insertions(+), 59 deletions(-)
Wolfgang Denk - Oct. 6, 2011, 9:15 p.m.
Dear Gerlando Falauto,

In message <1317384298-27025-2-git-send-email-gerlando.falauto@keymile.com> you wrote:
> 
> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
> ---
>  common/cmd_nvedit.c   |  150 ++++++++++++++++++++++++++++++-------------------
>  common/env_common.c   |   15 ++++-
>  include/environment.h |    2 +
>  include/search.h      |   13 ++++
>  lib/hashtable.c       |   48 ++++++++++++++++
>  5 files changed, 169 insertions(+), 59 deletions(-)

Checkpatch says:

total: 5 errors, 15 warnings, 353 lines checked

Please clean up and resubmit.  Thanks.

Best regards,

Wolfgang Denk

Patch

diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
index e8b116d..05e365a 100644
--- a/common/cmd_nvedit.c
+++ b/common/cmd_nvedit.c
@@ -194,32 +194,23 @@  static int do_env_grep (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[
 #endif
 
 /*
- * Set a new environment variable,
- * or replace or delete an existing one.
+ * Performs consistency checking before setting, replacing,
+ * or deleting an environment variable, then (if successful)
+ * apply the changes to internals so to make them effective.
+ * Code for this function was taken out of _do_env_set(),
+ * which now calls it.
+ * Also called as a callback function by himport_ex().
+ * Returns 0 in case of success, 1 in case of failure.
+ * When (flag & H_FORCE) is set, force overwriting of
+ * write-once variables.
  */
 
-int _do_env_set (int flag, int argc, char * const argv[])
+int env_check_apply(const char *name, const char *oldval,
+		    const char *newval, int flag)
 {
 	bd_t  *bd = gd->bd;
-	int   i, len;
+	int   i;
 	int   console = -1;
-	char  *name, *value, *s;
-	ENTRY e, *ep;
-
-	name = argv[1];
-
-	if (strchr(name, '=')) {
-		printf("## Error: illegal character '=' in variable name \"%s\"\n", name);
-		return 1;
-	}
-
-	env_id++;
-	/*
-	 * search if variable with this name already exists
-	 */
-	e.key = name;
-	e.data = NULL;
-	hsearch_r(e, FIND, &ep, &env_htab);
 
 	/* Check for console redirection */
 	if (strcmp(name, "stdin") == 0)
@@ -230,22 +221,22 @@  int _do_env_set (int flag, int argc, char * const argv[])
 		console = stderr;
 
 	if (console != -1) {
-		if (argc < 3) {		/* Cannot delete it! */
+		if ((newval == NULL) || (*newval == '\0')) {		/* Cannot delete it! */
 			printf("Can't delete \"%s\"\n", name);
 			return 1;
 		}
 
 #ifdef CONFIG_CONSOLE_MUX
-		i = iomux_doenv(console, argv[2]);
+		i = iomux_doenv(console, newval);
 		if (i)
 			return i;
 #else
 		/* Try assigning specified device */
-		if (console_assign(console, argv[2]) < 0)
+		if (console_assign(console, newval) < 0)
 			return 1;
 
 #ifdef CONFIG_SERIAL_MULTI
-		if (serial_assign(argv[2]) < 0)
+		if (serial_assign(newval) < 0)
 			return 1;
 #endif
 #endif /* CONFIG_CONSOLE_MUX */
@@ -255,23 +246,27 @@  int _do_env_set (int flag, int argc, char * const argv[])
 	 * Some variables like "ethaddr" and "serial#" can be set only
 	 * once and cannot be deleted; also, "ver" is readonly.
 	 */
-	if (ep) {		/* variable exists */
+	if (oldval != NULL) { /* variable exists */
 #ifndef CONFIG_ENV_OVERWRITE
-		if ((strcmp(name, "serial#") == 0) ||
+		if ( ((flag & H_FORCE) == 0) &&
+		    ((strcmp(name, "serial#") == 0) ||
 		    ((strcmp(name, "ethaddr") == 0)
 #if defined(CONFIG_OVERWRITE_ETHADDR_ONCE) && defined(CONFIG_ETHADDR)
-		     && (strcmp(ep->data, MK_STR(CONFIG_ETHADDR)) != 0)
+		     && (strcmp(oldval, MK_STR(CONFIG_ETHADDR)) != 0)
 #endif	/* CONFIG_OVERWRITE_ETHADDR_ONCE && CONFIG_ETHADDR */
 		    ) ) {
 			printf("Can't overwrite \"%s\"\n", name);
 			return 1;
 		}
 #endif
+	}
+	if ((oldval != NULL) /* variable exists */
+	|| ((flag & H_NOCLEAR) == 0)) { /* or we are in a scratched-out environment */
 		/*
 		 * Switch to new baudrate if new baudrate is supported
 		 */
 		if (strcmp(name, "baudrate") == 0) {
-			int baudrate = simple_strtoul(argv[2], NULL, 10);
+			int baudrate = simple_strtoul(newval, NULL, 10);
 			int i;
 			for (i = 0; i < N_BAUDRATES; ++i) {
 				if (baudrate == baudrate_table[i])
@@ -282,6 +277,10 @@  int _do_env_set (int flag, int argc, char * const argv[])
 					baudrate);
 				return 1;
 			}
+			if (gd->baudrate == baudrate) {
+				/* In case of unchanged baudrate, let's just say it's OK */
+				return 0;
+			}
 			printf ("## Switch baudrate to %d bps and press ENTER ...\n",
 				baudrate);
 			udelay(50000);
@@ -299,6 +298,71 @@  int _do_env_set (int flag, int argc, char * const argv[])
 		}
 	}
 
+	/*
+	 * Some variables should be updated when the corresponding
+	 * entry in the environment is changed
+	 */
+
+	if (strcmp(name, "ipaddr") == 0) {
+		const char *s = newval;	/* always use only one arg */
+		char *e;
+		unsigned long addr;
+		bd->bi_ip_addr = 0;
+		for (addr = 0, i = 0; i < 4; ++i) {
+			ulong val = s ? simple_strtoul(s, &e, 10) : 0;
+			addr <<= 8;
+			addr  |= (val & 0xFF);
+			if (s) s = (*e) ? e+1 : e;
+		}
+		bd->bi_ip_addr = htonl(addr);
+		return 0;
+	} else if (strcmp(newval, "loadaddr") == 0) {
+		load_addr = simple_strtoul(newval, NULL, 16);
+		return 0;
+	}
+#if defined(CONFIG_CMD_NET)
+	else if (strcmp(newval, "bootfile") == 0) {
+		copy_filename(BootFile, newval, sizeof(BootFile));
+		return 0;
+	}
+#endif
+	return 0;
+}
+
+/*
+ * Set a new environment variable,
+ * or replace or delete an existing one.
+*/
+int _do_env_set (int flag, int argc, char * const argv[])
+{
+	int   i, len;
+	char  *name, *value, *s;
+	ENTRY e, *ep;
+
+	name = argv[1];
+	value = argv[2];
+
+	if (strchr(name, '=')) {
+		printf("## Error: illegal character '=' in variable name \"%s\"\n", name);
+		return 1;
+	}
+
+	env_id++;
+	/*
+	 * search if variable with this name already exists
+	 */
+	e.key = name;
+	e.data = NULL;
+	hsearch_r(e, FIND, &ep, &env_htab);
+
+	/* Perform requested checks. Notice how since we are overwriting
+	 * a single variable, we need to set H_NOCLEAR */
+	if (env_check_apply(name, ep ? ep->data : NULL, value, H_NOCLEAR))
+	{
+		debug("check function did not approve, refusing\n");
+		return 1;
+	}
+
 	/* Delete only ? */
 	if ((argc < 3) || argv[2] == NULL) {
 		int rc = hdelete_r(name, &env_htab);
@@ -336,34 +400,6 @@  int _do_env_set (int flag, int argc, char * const argv[])
 		return 1;
 	}
 
-	/*
-	 * Some variables should be updated when the corresponding
-	 * entry in the environment is changed
-	 */
-
-	if (strcmp(name, "ipaddr") == 0) {
-		char *s = argv[2];	/* always use only one arg */
-		char *e;
-		unsigned long addr;
-		bd->bi_ip_addr = 0;
-		for (addr = 0, i = 0; i < 4; ++i) {
-			ulong val = s ? simple_strtoul(s, &e, 10) : 0;
-			addr <<= 8;
-			addr  |= (val & 0xFF);
-			if (s) s = (*e) ? e+1 : e;
-		}
-		bd->bi_ip_addr = htonl(addr);
-		return 0;
-	} else if (strcmp(argv[1], "loadaddr") == 0) {
-		load_addr = simple_strtoul(argv[2], NULL, 16);
-		return 0;
-	}
-#if defined(CONFIG_CMD_NET)
-	else if (strcmp(argv[1], "bootfile") == 0) {
-		copy_filename(BootFile, argv[2], sizeof(BootFile));
-		return 0;
-	}
-#endif
 	return 0;
 }
 
diff --git a/common/env_common.c b/common/env_common.c
index 19149b5..7e1d824 100644
--- a/common/env_common.c
+++ b/common/env_common.c
@@ -172,6 +172,9 @@  const uchar *env_get_addr (int index)
 
 void set_default_env(const char *s)
 {
+	/* By default, do not apply changes as they will eventually
+	 * be applied by someone else */
+	apply_cb apply_function = NULL;
 	if (sizeof(default_environment) > ENV_SIZE) {
 		puts("*** Error - default environment is too large\n\n");
 		return;
@@ -183,14 +186,22 @@  void set_default_env(const char *s)
 				"using default environment\n\n",
 				s+1);
 		} else {
+			/* This set_to_default was explicitly asked for
+			 * by the user, as opposed to being a recovery
+			 * mechanism. Therefore we chack every single
+			 * variable and apply changes to the system
+			 * right away (e.g. baudrate, console).
+			 */
+			apply_function = env_check_apply;
 			puts(s);
 		}
 	} else {
 		puts("Using default environment\n\n");
 	}
 
-	if (himport_r(&env_htab, (char *)default_environment,
-		    sizeof(default_environment), '\0', 0) == 0) {
+	if (himport_ex(&env_htab, (char *)default_environment,
+		    sizeof(default_environment), '\0', 0,
+		      0, NULL, apply_function) == 0) {
 		error("Environment import failed: errno = %d\n", errno);
 	}
 	gd->flags |= GD_FLG_ENV_READY;
diff --git a/include/environment.h b/include/environment.h
index 6394a96..02c3488 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -174,6 +174,8 @@  void set_default_env(const char *s);
 /* Import from binary representation into hash table */
 int env_import(const char *buf, int check);
 
+int env_check_apply(const char *name, const char *oldval, const char *newval, int flag);
+
 #endif
 
 #endif	/* _ENVIRONMENT_H_ */
diff --git a/include/search.h b/include/search.h
index b4edd43..4d5b082 100644
--- a/include/search.h
+++ b/include/search.h
@@ -46,6 +46,11 @@  typedef struct entry {
 /* Opaque type for internal use.  */
 struct _ENTRY;
 
+/* Callback function to be called for checking whether the given change may
+ * be applied or not. Must return 0 for approval, 1 for denial. */
+typedef int (*apply_cb)(const char *name, const char *oldval,
+			const char *newval, int flag);
+
 /*
  * Family of hash table handling functions.  The functions also
  * have reentrant counterparts ending with _r.  The non-reentrant
@@ -97,7 +102,15 @@  extern int himport_r(struct hsearch_data *__htab,
 		     const char *__env, size_t __size, const char __sep,
 		     int __flag);
 
+extern int himport_ex(struct hsearch_data *__htab,
+		     const char *__env, size_t __size, const char __sep,
+		     int __flag,
+		     int __argc, char * const __argv[],
+		     apply_cb apply);
+
+
 /* Flags for himport_r() */
 #define	H_NOCLEAR	1	/* do not clear hash table before importing */
+#define H_FORCE		2	/* force overwriting of read-only or write-once variables */
 
 #endif /* search.h */
diff --git a/lib/hashtable.c b/lib/hashtable.c
index 026dbca..b088168 100644
--- a/lib/hashtable.c
+++ b/lib/hashtable.c
@@ -628,6 +628,34 @@  ssize_t hexport_r(struct hsearch_data *htab, const char sep,
 int himport_r(struct hsearch_data *htab,
 	      const char *env, size_t size, const char sep, int flag)
 {
+	return himport_ex(htab, env, size, sep, flag, 0, NULL, NULL);
+}
+
+/* Check whether variable name is amongst vars[] */
+static int process_var(const char *name, int nvars, char * const vars[])
+{
+	int i = 0;
+	/* No variables specified means process all of them*/
+	if (nvars == 0)
+		return 1;
+
+	for (i = 0; i < nvars; i++) {
+		if (!strcmp(name, vars[i])) {
+			return 1;
+		}
+	}
+	debug ("Skipping non-listed variable %s\n", name);
+	return 0;
+}
+
+
+
+int himport_ex(struct hsearch_data *htab,
+	      const char *env, size_t size, const char sep, int flag,
+	      int nvars, char * const vars[],
+	      int(*apply)(const char *, const char *, const char *, int)
+	      )
+{
 	char *data, *sp, *dp, *name, *value;
 
 	/* Test for correct arguments.  */
@@ -713,6 +741,8 @@  int himport_r(struct hsearch_data *htab,
 			*dp++ = '\0';	/* terminate name */
 
 			debug("DELETE CANDIDATE: \"%s\"\n", name);
+			if (!process_var(name, nvars, vars))
+				continue;
 
 			if (hdelete_r(name, htab) == 0)
 				debug("DELETE ERROR ##############################\n");
@@ -730,10 +760,28 @@  int himport_r(struct hsearch_data *htab,
 		*sp++ = '\0';	/* terminate value */
 		++dp;
 
+		/* Skip variables which are not supposed to be treated */
+		if (!process_var(name, nvars, vars))
+			continue;
+
 		/* enter into hash table */
 		e.key = name;
 		e.data = value;
 
+		/* if there is an apply function, check what it has to say */
+		if (apply != NULL)
+		{
+			debug("searching before calling cb function for variable %s\n", name);
+			/* Check for previous value so to provide it to apply callback */
+			hsearch_r(e, FIND, &rv, htab);
+			debug("previous value was %s\n", rv ? rv->data : "");
+			if (apply(name, rv ? rv->data : NULL, value, flag))
+			{
+				debug("callback function refused to set variable %s, skipping it!\n", name);
+				continue;
+			}
+		}
+
 		hsearch_r(e, ENTER, &rv, htab);
 		if (rv == NULL) {
 			printf("himport_r: can't insert \"%s=%s\" into hash table\n",