From 4656e0a3600102c798402947bb26f9035b391a13 Mon Sep 17 00:00:00 2001 From: Tilman Schmidt Date: Sat, 21 Mar 2015 20:15:32 +0100 Subject: [PATCH] isdn/gigaset: restructure modem response parser (4) Restructure the control structure of the modem response parser to improve readability and error handling. Signed-off-by: Tilman Schmidt Signed-off-by: David S. Miller --- drivers/isdn/gigaset/ev-layer.c | 258 +++++++++++++++++++------------- 1 file changed, 151 insertions(+), 107 deletions(-) diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c index dc6e6a396531..1cfcea62aed9 100644 --- a/drivers/isdn/gigaset/ev-layer.c +++ b/drivers/isdn/gigaset/ev-layer.c @@ -389,6 +389,20 @@ zsau_resp[] = {NULL, ZSAU_UNKNOWN} }; +/* check for and remove fixed string prefix + * If s starts with prefix terminated by a non-alphanumeric character, + * return pointer to the first character after that, otherwise return NULL. + */ +static char *skip_prefix(char *s, const char *prefix) +{ + while (*prefix) + if (*s++ != *prefix++) + return NULL; + if (isalnum(*s)) + return NULL; + return s; +} + /* queue event with CID */ static void add_cid_event(struct cardstate *cs, int cid, int type, void *ptr, int parameter) @@ -430,15 +444,11 @@ static void add_cid_event(struct cardstate *cs, int cid, int type, */ void gigaset_handle_modem_response(struct cardstate *cs) { - unsigned char *argv[MAX_REC_PARAMS + 1]; - int params; - int i, j; - char *psep, *ptr; + char *eoc, *psep, *ptr; const struct resp_type_t *rt; const struct zsau_resp_t *zr; - int curarg; - int abort; int cid, parameter; + u8 type, value; if (!cs->cbytes) { /* ignore additional LFs/CRs (M10x config mode or cx100) */ @@ -456,6 +466,19 @@ void gigaset_handle_modem_response(struct cardstate *cs) return; } + /* look up response type */ + for (rt = resp_type; rt->response; ++rt) { + eoc = skip_prefix(cs->respdata, rt->response); + if (eoc) + break; + } + if (!rt->response) { + add_cid_event(cs, 0, RSP_NONE, NULL, 0); + gig_dbg(DEBUG_EVENT, "unknown modem response: '%s'\n", + cs->respdata); + return; + } + /* check for CID */ psep = strrchr(cs->respdata, ';'); if (psep && @@ -468,120 +491,141 @@ void gigaset_handle_modem_response(struct cardstate *cs) cid = 0; } - /* parse line */ - argv[0] = cs->respdata; - params = 1; - for (i = 0; i < cs->cbytes; i++) - switch (cs->respdata[i]) { - case ';': - case ',': - case '=': - cs->respdata[i] = 0; - if (params > MAX_REC_PARAMS) - dev_warn(cs->dev, - "too many parameters in response\n"); - else - argv[params++] = cs->respdata + i + 1; - } - - gig_dbg(DEBUG_EVENT, "CMD received: %s", argv[0]); + gig_dbg(DEBUG_EVENT, "CMD received: %s", cs->respdata); if (cid) gig_dbg(DEBUG_EVENT, "CID: %d", cid); - gig_dbg(DEBUG_EVENT, "available params: %d", params - 1); - for (j = 1; j < params; j++) - gig_dbg(DEBUG_EVENT, "param %d: %s", j, argv[j]); - - abort = 1; - curarg = 0; - while (curarg < params) { - for (rt = resp_type; rt->response; ++rt) - if (!strcmp(argv[curarg], rt->response)) - break; - if (!rt->response) { - add_cid_event(cs, 0, RSP_NONE, NULL, 0); - gig_dbg(DEBUG_EVENT, "unknown modem response: '%s'\n", - argv[curarg]); - break; - } + switch (rt->type) { + case RT_NOTHING: + /* check parameter separator */ + if (*eoc) + goto bad_param; /* extra parameter */ - ++curarg; + add_cid_event(cs, cid, rt->resp_code, NULL, 0); + break; - switch (rt->type) { - case RT_NOTHING: - add_cid_event(cs, cid, rt->resp_code, NULL, 0); - break; - case RT_RING: - if (!cid) { - dev_err(cs->dev, - "received RING without CID!\n"); - add_cid_event(cs, 0, RSP_INVAL, NULL, 0); - abort = 1; - } else { - add_cid_event(cs, 0, rt->resp_code, NULL, cid); - abort = 0; - } - break; - case RT_ZSAU: - if (curarg >= params) { - add_cid_event(cs, cid, rt->resp_code, NULL, - ZSAU_NONE); - break; - } - for (zr = zsau_resp; zr->str; ++zr) - if (!strcmp(argv[curarg], zr->str)) + case RT_RING: + /* check parameter separator */ + if (!*eoc) + eoc = NULL; /* no parameter */ + else if (*eoc++ != ',') + goto bad_param; + + add_cid_event(cs, 0, rt->resp_code, NULL, cid); + + /* process parameters as individual responses */ + while (eoc) { + /* look up parameter type */ + psep = NULL; + for (rt = resp_type; rt->response; ++rt) { + psep = skip_prefix(eoc, rt->response); + if (psep) break; - if (!zr->str) + } + + /* all legal parameters are of type RT_STRING */ + if (!psep || rt->type != RT_STRING) { dev_warn(cs->dev, - "%s: unknown parameter %s after ZSAU\n", - __func__, argv[curarg]); - add_cid_event(cs, cid, rt->resp_code, NULL, zr->code); - ++curarg; - break; - case RT_STRING: - if (curarg < params) { - ptr = kstrdup(argv[curarg], GFP_ATOMIC); - if (!ptr) - dev_err(cs->dev, "out of memory\n"); - ++curarg; - } else { - ptr = NULL; + "illegal RING parameter: '%s'\n", + eoc); + return; } - gig_dbg(DEBUG_EVENT, "string==%s", ptr ? ptr : "NULL"); + + /* skip parameter value separator */ + if (*psep++ != '=') + goto bad_param; + + /* look up end of parameter */ + eoc = strchr(psep, ','); + if (eoc) + *eoc++ = 0; + + /* retrieve parameter value */ + ptr = kstrdup(psep, GFP_ATOMIC); + + /* queue event */ add_cid_event(cs, cid, rt->resp_code, ptr, 0); - break; - case RT_ZCAU: - parameter = -1; - if (curarg + 1 < params) { - u8 type, value; - - i = kstrtou8(argv[curarg++], 16, &type); - j = kstrtou8(argv[curarg++], 16, &value); - if (i == 0 && j == 0) - parameter = (type << 8) | value; - } else - curarg = params - 1; - add_cid_event(cs, cid, rt->resp_code, NULL, parameter); - break; - case RT_NUMBER: - if (curarg >= params || - kstrtoint(argv[curarg++], 10, ¶meter)) - parameter = -1; - gig_dbg(DEBUG_EVENT, "parameter==%d", parameter); - add_cid_event(cs, cid, rt->resp_code, NULL, parameter); - if (rt->resp_code == RSP_ZDLE) - cs->dle = parameter; - break; } + break; - if (abort) + case RT_ZSAU: + /* check parameter separator */ + if (!*eoc) { + /* no parameter */ + add_cid_event(cs, cid, rt->resp_code, NULL, ZSAU_NONE); break; - } + } + if (*eoc++ != '=') + goto bad_param; - if (curarg != params) - gig_dbg(DEBUG_EVENT, - "invalid number of processed parameters: %d/%d", - curarg, params); + /* look up parameter value */ + for (zr = zsau_resp; zr->str; ++zr) + if (!strcmp(eoc, zr->str)) + break; + if (!zr->str) + goto bad_param; + + add_cid_event(cs, cid, rt->resp_code, NULL, zr->code); + break; + + case RT_STRING: + /* check parameter separator */ + if (*eoc++ != '=') + goto bad_param; + + /* retrieve parameter value */ + ptr = kstrdup(eoc, GFP_ATOMIC); + + /* queue event */ + add_cid_event(cs, cid, rt->resp_code, ptr, 0); + break; + + case RT_ZCAU: + /* check parameter separators */ + if (*eoc++ != '=') + goto bad_param; + psep = strchr(eoc, ','); + if (!psep) + goto bad_param; + *psep++ = 0; + + /* decode parameter values */ + if (kstrtou8(eoc, 16, &type) || kstrtou8(psep, 16, &value)) { + *--psep = ','; + goto bad_param; + } + parameter = (type << 8) | value; + + add_cid_event(cs, cid, rt->resp_code, NULL, parameter); + break; + + case RT_NUMBER: + /* check parameter separator */ + if (*eoc++ != '=') + goto bad_param; + + /* decode parameter value */ + if (kstrtoint(eoc, 10, ¶meter)) + goto bad_param; + + /* special case ZDLE: set flag before queueing event */ + if (rt->resp_code == RSP_ZDLE) + cs->dle = parameter; + + add_cid_event(cs, cid, rt->resp_code, NULL, parameter); + break; + +bad_param: + /* parameter unexpected, incomplete or malformed */ + dev_warn(cs->dev, "bad parameter in response '%s'\n", + cs->respdata); + add_cid_event(cs, cid, rt->resp_code, NULL, -1); + break; + + default: + dev_err(cs->dev, "%s: internal error on '%s'\n", + __func__, cs->respdata); + } } EXPORT_SYMBOL_GPL(gigaset_handle_modem_response); -- 2.34.1