From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerlando Falauto Date: Mon, 02 Apr 2012 22:44:21 +0200 Subject: [U-Boot] [PATCH v3 3/6] env: add check/apply logic to himport_r() In-Reply-To: <201204022101.38606.marex@denx.de> References: <1321634955-5561-1-git-send-email-gerlando.falauto@keymile.com> <1333391204-16318-4-git-send-email-gerlando.falauto@keymile.com> <201204022100.05408.marex@denx.de> <201204022101.38606.marex@denx.de> Message-ID: <4F7A0FA5.1030301@keymile.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 04/02/2012 09:01 PM, Marek Vasut wrote: > Dear Marek Vasut, > >> Dear Gerlando Falauto, >> >>> Change hashtable so that a callback function will decide whether a >>> variable can be overwritten, and possibly apply the changes. >>> >>> So add a new field to struct hsearch_data: >>> o "apply" callback function to check whether a variable can be >>> >>> overwritten, and possibly immediately apply the changes; >>> when NULL, no check is performed. >>> >>> And a new argument to himport_r(): >>> o "do_apply": whether to call the apply callback function >>> >>> NOTE: This patch does not change the current behavior. >>> >>> Signed-off-by: Gerlando Falauto >>> --- >>> >>> common/cmd_nvedit.c | 3 ++- >>> common/env_common.c | 8 +++++--- >>> include/environment.h | 9 +++++++++ >>> include/search.h | 14 +++++++++++++- >>> lib/hashtable.c | 20 +++++++++++++++++++- >>> 5 files changed, 48 insertions(+), 6 deletions(-) >>> >>> diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c >>> index 59668a6..fc6165f 100644 >>> --- a/common/cmd_nvedit.c >>> +++ b/common/cmd_nvedit.c >>> @@ -201,6 +201,7 @@ static int do_env_grep(cmd_tbl_t *cmdtp, int flag, >>> >>> * 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 instead. >>> + * Also called as a callback function by himport_r(). >>> >>> * Returns 0 in case of success, 1 in case of failure. >>> * When (flag& H_FORCE) is set, do not print out any error message and >>> >>> force * overwriting of write-once variables. >>> @@ -931,7 +932,7 @@ static int do_env_import(cmd_tbl_t *cmdtp, int flag, >>> >>> } >>> >>> if (himport_r(&env_htab, addr, size, sep, del ? 0 : H_NOCLEAR, >>> >>> - 0, NULL) == 0) { >>> + 0, NULL, 0 /* do_apply */) == 0) { >>> >>> error("Environment import failed: errno = %d\n", errno); >>> return 1; >>> >>> } >>> >>> diff --git a/common/env_common.c b/common/env_common.c >>> index a93c062..5558c1c 100644 >>> --- a/common/env_common.c >>> +++ b/common/env_common.c >>> @@ -122,7 +122,9 @@ const uchar default_environment[] = { >>> >>> "\0" >>> >>> }; >>> >>> -struct hsearch_data env_htab; >>> +struct hsearch_data env_htab = { >>> + .apply = env_check_apply, >>> +}; >>> >>> static uchar __env_get_char_spec(int index) >>> { >>> >>> @@ -183,7 +185,7 @@ void set_default_env(const char *s) >>> >>> if (himport_r(&env_htab, (char *)default_environment, >>> >>> sizeof(default_environment), '\0', 0, >>> >>> - 0, NULL) == 0) >>> + 0, NULL, 0 /* do_apply */) == 0) >> >> Please replace that 0 /*...*/ stuff with simple NULL > > Oh, it's integer ... so just remove the comment, sorry. The comment would have been a way to shed some light on one of the 8 arguments the function takes. But if it's against some coding style guideline, I'll simply remove it. > >> >>> error("Environment import failed: errno = %d\n", errno); >>> >>> gd->flags |= GD_FLG_ENV_READY; >>> >>> @@ -209,7 +211,7 @@ int env_import(const char *buf, int check) >>> >>> } >>> >>> if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, >>> >>> - 0, NULL)) { >>> + 0, NULL, 0 /* do_apply */)) { >> >> DTTO, otherwise looks fine. >> >>> gd->flags |= GD_FLG_ENV_READY; >>> return 1; >>> >>> } >>> >>> diff --git a/include/environment.h b/include/environment.h >>> index 1ef44f3..236e179 100644 >>> --- a/include/environment.h >>> +++ b/include/environment.h >>> @@ -193,6 +193,15 @@ void set_default_env(const char *s); >>> >>> /* Import from binary representation into hash table */ >>> int env_import(const char *buf, int check); >>> >>> +/* >>> + * Check if variable "name" can be changed from oldval to newval, >>> + * and if so, apply the changes (e.g. baudrate). >>> + * When (flag& H_FORCE) is set, it does not print out any error >>> + * message and forces overwriting of write-once variables. >>> + */ >>> +int env_check_apply(const char *name, const char *oldval, >>> + const char *newval, int flag); >>> + >>> >>> #endif /* DO_DEPS_ONLY */ >>> >>> #endif /* _ENVIRONMENT_H_ */ >>> >>> diff --git a/include/search.h b/include/search.h >>> index 94d75fc..721c8ac 100644 >>> --- a/include/search.h >>> +++ b/include/search.h >>> @@ -57,6 +57,16 @@ struct hsearch_data { >>> >>> struct _ENTRY *table; >>> unsigned int size; >>> unsigned int filled; >>> >>> +/* >>> + * Callback function which will check whether the given change for >>> variable + * "name" from "oldval" to "newval" may be applied or not, and >>> possibly apply + * such change. >>> + * When (flag& H_FORCE) is set, it shall not print out any error >>> message and + * shall force overwriting of write-once variables. >>> +.* Must return 0 for approval, 1 for denial. >>> + */ >>> + int (*apply)(const char *name, const char *oldval, >>> + const char *newval, int flag); >>> >>> }; >>> >>> /* Create a new hashing table which will at most contain NEL elements. >>> */ >>> >>> @@ -97,10 +107,12 @@ extern ssize_t hexport_r(struct hsearch_data >>> *__htab, >>> >>> /* >>> >>> * nvars: length of vars array >>> * vars: array of strings (variable names) to import (nvars == 0 means >>> >>> all) + * do_apply: whether to call callback function to check the new >>> argument, + * and possibly apply changes (false means accept everything) >>> >>> */ >>> >>> extern int himport_r(struct hsearch_data *__htab, >>> >>> const char *__env, size_t __size, const char __sep, >>> >>> - int __flag, int nvars, char * const vars[]); >>> + int __flag, int nvars, char * const vars[], int do_apply); >>> >>> /* Flags for himport_r() */ >>> #define H_NOCLEAR (1<< 0) /* do not clear hash table before >> >> importing */ >> >>> diff --git a/lib/hashtable.c b/lib/hashtable.c >>> index 0610e86..6cfba56 100644 >>> --- a/lib/hashtable.c >>> +++ b/lib/hashtable.c >>> @@ -658,7 +658,7 @@ static int is_var_in_set(const char *name, int nvars, >>> char * const vars[]) >>> >>> int himport_r(struct hsearch_data *htab, >>> >>> const char *env, size_t size, const char sep, int flag, >>> >>> - int nvars, char * const vars[]) >>> + int nvars, char * const vars[], int do_apply) >>> >>> { >>> >>> char *data, *sp, *dp, *name, *value; >>> >>> @@ -772,6 +772,24 @@ int himport_r(struct hsearch_data *htab, >>> >>> e.key = name; >>> e.data = value; >>> >>> + /* if there is an apply function, check what it has to say */ >>> + if (do_apply&& htab->apply != NULL) { >>> + debug("searching before calling cb function" >>> + " for %s\n", name); >>> + /* >>> + * Search for variable in existing env, so to pass >>> + * its previous value to the apply callback >>> + */ >>> + hsearch_r(e, FIND,&rv, htab); >>> + debug("previous value was %s\n", rv ? rv->data : ""); >>> + if (htab->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",