build: constify `memchr()`/`strchr()`/etc result variables

And a few variables around.

There remain cases where the accepted pointer is const, yet the returned
pointer is written to.

Partly addressing (glibc 2.43):
```
* For ISO C23, the functions bsearch, memchr, strchr, strpbrk, strrchr,
  strstr, wcschr, wcspbrk, wcsrchr, wcsstr and wmemchr that return
  pointers into their input arrays now have definitions as macros that
  return a pointer to a const-qualified type when the input argument is
  a pointer to a const-qualified type.
```
Ref: https://lists.gnu.org/archive/html/info-gnu/2026-01/msg00005.html

Reported-by: Rudi Heitbaum
Ref: #20420

Closes #20421

diff --git a/lib/cookie.c b/lib/cookie.c
index 2c57226dc5cb4726104f8c7c4b7449595cbc3b3d..5d7cd133106a9597ed01406014117306e8f2530b 100644 (file)
--- a/lib/cookie.c
+++ b/lib/cookie.c
@@ -331,7 +331,7 @@ static bool bad_domain(const char *domain, size_t len)
     return FALSE;
   else {
     /* there must be a dot present, but that dot must not be a trailing dot */
-    char *dot = memchr(domain, '.', len);
+    const char *dot = memchr(domain, '.', len);
     if(dot) {
       size_t i = dot - domain;
       if((len - i) > 1)

diff --git a/lib/dict.c b/lib/dict.c
index fcdea918cf2b8096fb51c0b94c0cb9d5201a8cf2..832da30ce4549dd66d9fea17774619426b278f44 100644 (file)
--- a/lib/dict.c
+++ b/lib/dict.c
@@ -136,7 +136,7 @@ static CURLcode sendf(struct Curl_easy *data, const char *fmt, ...)
 
 static CURLcode dict_do(struct Curl_easy *data, bool *done)
 {
-  char *word;
+  const char *word;
   char *eword = NULL;
   char *ppath;
   char *database = NULL;

diff --git a/lib/doh.c b/lib/doh.c
index d992a17a9c2854e7ad1408ce91a4160f20adec12..88c09889bcf6011e062bebc3b54df1538e22f4ad 100644 (file)
--- a/lib/doh.c
+++ b/lib/doh.c
@@ -129,7 +129,7 @@ UNITTEST DOHcode doh_req_encode(const char *host,
   /* encode each label and store it in the QNAME */
   while(*hostp) {
     size_t labellen;
-    char *dot = strchr(hostp, '.');
+    const char *dot = strchr(hostp, '.');
     if(dot)
       labellen = dot - hostp;
     else

diff --git a/lib/ftp.c b/lib/ftp.c
index b244089a195ee2e638d3912f42b0038025f3a06f..1fda9c608dd0934469173c84a29e0db8d5c59384 100644 (file)
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -935,7 +935,7 @@ static CURLcode ftp_state_use_port(struct Curl_easy *data,
 
   if(data->set.str[STRING_FTPPORT] &&
      (strlen(data->set.str[STRING_FTPPORT]) > 1)) {
-    char *ip_end = NULL;
+    const char *ip_end = NULL;
 
 #ifdef USE_IPV6
     if(*string_ftpport == '[') {
@@ -1952,7 +1952,7 @@ static CURLcode ftp_state_pasv_resp(struct Curl_easy *data,
   if((ftpc->count1 == 0) &&
      (ftpcode == 229)) {
     /* positive EPSV response */
-    char *ptr = strchr(str, '(');
+    const char *ptr = strchr(str, '(');
     if(ptr) {
       char sep;
       ptr++;

diff --git a/lib/http.c b/lib/http.c
index 72316f7e4199d61fa49e0dd85db67a33f3e86318..b5627e61a88b6b40e717b04c4dafd44459dcbe92 100644 (file)
--- a/lib/http.c
+++ b/lib/http.c
@@ -3829,7 +3829,7 @@ static CURLcode verify_header(struct Curl_easy *data,
                               const char *hd, size_t hdlen)
 {
   struct SingleRequest *k = &data->req;
-  char *ptr = memchr(hd, 0x00, hdlen);
+  const char *ptr = memchr(hd, 0x00, hdlen);
   if(ptr) {
     /* this is bad, bail out */
     failf(data, "Nul byte in header");
@@ -4369,7 +4369,7 @@ static CURLcode http_parse_headers(struct Curl_easy *data,
   struct connectdata *conn = data->conn;
   CURLcode result = CURLE_OK;
   struct SingleRequest *k = &data->req;
-  char *end_ptr;
+  const char *end_ptr;
   bool leftover_body = FALSE;
 
   /* we have bytes for the next header, make sure it is not a folded header

diff --git a/lib/http_aws_sigv4.c b/lib/http_aws_sigv4.c
index 38e81fca434abc91de2e0c299277f62a933dea21..1eb680fb13886cee8f09db17c21b086ca05319a1 100644 (file)
--- a/lib/http_aws_sigv4.c
+++ b/lib/http_aws_sigv4.c
@@ -333,8 +333,8 @@ static CURLcode merge_duplicate_headers(struct curl_slist *head)
 
     if(compare_header_names(curr->data, next->data) == 0) {
       struct dynbuf buf;
-      char *colon_next;
-      char *val_next;
+      const char *colon_next;
+      const char *val_next;
 
       curlx_dyn_init(&buf, CURL_MAX_HTTP_HEADER);
 
@@ -441,8 +441,9 @@ static CURLcode make_headers(struct Curl_easy *data,
      semi-colon, are not added to this list.
      */
   for(l = data->set.headers; l; l = l->next) {
-    char *dupdata, *ptr;
-    char *sep = strchr(l->data, ':');
+    char *dupdata;
+    const char *ptr;
+    const char *sep = strchr(l->data, ':');
     if(!sep)
       sep = strchr(l->data, ';');
     if(!sep || (*sep == ':' && !*(sep + 1)))
@@ -729,7 +730,7 @@ UNITTEST CURLcode canon_query(const char *query, struct dynbuf *dq)
   for(index = 0; index < num_query_components; index++) {
     const char *in_key;
     size_t in_key_len;
-    char *offset;
+    const char *offset;
     size_t query_part_len = curlx_dyn_len(&query_array[index]);
     char *query_part = curlx_dyn_ptr(&query_array[index]);
 

diff --git a/lib/netrc.c b/lib/netrc.c
index 0678733d22f226297390697c390e89a6710309c1..baabe917a75ab4a1c33f053fdcc90ae604d99f7f 100644 (file)
--- a/lib/netrc.c
+++ b/lib/netrc.c
@@ -122,7 +122,7 @@ static NETRCcode parsenetrc(struct store_netrc *store,
                               any order */
   bool our_login = FALSE;  /* found our login name */
   bool done = FALSE;
-  char *netrcbuffer;
+  const char *netrcbuffer;
   struct dynbuf token;
   struct dynbuf *filebuf = &store->filebuf;
   DEBUGASSERT(!*passwordp);
@@ -326,7 +326,7 @@ static NETRCcode parsenetrc(struct store_netrc *store,
       tok = ++tok_end;
     }
     if(!done) {
-      char *nl = NULL;
+      const char *nl = NULL;
       if(tok)
         nl = strchr(tok, '\n');
       if(!nl)

diff --git a/lib/pingpong.c b/lib/pingpong.c
index 7de902492bcd98ee33791bbaa46c5d6044488710..a2ca05ae4767e3649f3f1160688da8e71e2bea82 100644 (file)
--- a/lib/pingpong.c
+++ b/lib/pingpong.c
@@ -292,8 +292,8 @@ CURLcode Curl_pp_readresp(struct Curl_easy *data,
     }
 
     do {
-      char *line = curlx_dyn_ptr(&pp->recvbuf);
-      char *nl = memchr(line, '\n', curlx_dyn_len(&pp->recvbuf));
+      const char *line = curlx_dyn_ptr(&pp->recvbuf);
+      const char *nl = memchr(line, '\n', curlx_dyn_len(&pp->recvbuf));
       if(nl) {
         /* a newline is CRLF in pp-talk, so the CR is ignored as
            the line is not really terminated until the LF comes */

diff --git a/lib/pop3.c b/lib/pop3.c
index fe9f4323de03fbf52eaba1cf9d2358aecb0d1dfa..857cf26c6b912c8e1c9cbf307e354876382a2682 100644 (file)
--- a/lib/pop3.c
+++ b/lib/pop3.c
@@ -809,8 +809,8 @@ static CURLcode pop3_state_servergreet_resp(struct Curl_easy *data,
   }
   else if(len > 3) {
     /* Does the server support APOP authentication? */
-    char *lt;
-    char *gt = NULL;
+    const char *lt;
+    const char *gt = NULL;
 
     /* Look for the APOP timestamp */
     lt = memchr(line, '<', len);
@@ -820,7 +820,7 @@ static CURLcode pop3_state_servergreet_resp(struct Curl_easy *data,
     if(gt) {
       /* the length of the timestamp, including the brackets */
       size_t timestamplen = gt - lt + 1;
-      char *at = memchr(lt, '@', timestamplen);
+      const char *at = memchr(lt, '@', timestamplen);
       /* If the timestamp does not contain '@' it is not (as required by
          RFC-1939) conformant to the RFC-822 message id syntax, and we
          therefore do not use APOP authentication. */

diff --git a/lib/telnet.c b/lib/telnet.c
index 56cabce0b8ff80c1f65cd3d68e30d76827a063e6..c06b7a1b1fdb137a23d917c6b411bef95586227e 100644 (file)
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -115,8 +115,8 @@ struct TELNET {
   int himq[256];
   int him_preferred[256];
   int subnegotiation[256];
-  char *subopt_ttype;                /* Set with suboption TTYPE */
-  char *subopt_xdisploc;             /* Set with suboption XDISPLOC */
+  const char *subopt_ttype;          /* Set with suboption TTYPE */
+  const char *subopt_xdisploc;       /* Set with suboption XDISPLOC */
   unsigned short subopt_wsx;         /* Set with suboption NAWS */
   unsigned short subopt_wsy;         /* Set with suboption NAWS */
   TelnetReceive telrcv_state;
@@ -860,9 +860,9 @@ static CURLcode check_telnet_options(struct Curl_easy *data,
 
   for(head = data->set.telnet_options; head && !result; head = head->next) {
     size_t olen;
-    char *option = head->data;
-    char *arg;
-    char *sep = strchr(option, '=');
+    const char *option = head->data;
+    const char *arg;
+    const char *sep = strchr(option, '=');
     if(sep) {
       olen = sep - option;
       arg = ++sep;
@@ -1037,7 +1037,7 @@ static CURLcode suboption(struct Curl_easy *data, struct TELNET *tn)
         return CURLE_BAD_FUNCTION_ARGUMENT;
       /* Add the variable if it fits */
       if(len + tmplen < (int)sizeof(temp) - 6) {
-        char *s = strchr(v->data, ',');
+        const char *s = strchr(v->data, ',');
         if(!s)
           len += curl_msnprintf((char *)&temp[len], sizeof(temp) - len,
                                 "%c%s", CURL_NEW_ENV_VAR, v->data);

diff --git a/lib/url.c b/lib/url.c
index c64dca1d5617e1b1cfd3c52e73bf853dd3b8c09b..943ae6ad62f6c16b09039714e147c6d0b6f5cb2a 100644 (file)
--- a/lib/url.c
+++ b/lib/url.c
@@ -2812,7 +2812,7 @@ static CURLcode parse_connect_to_string(struct Curl_easy *data,
     }
     else {
       /* check whether the URL's port matches */
-      char *ptr_next = strchr(ptr, ':');
+      const char *ptr_next = strchr(ptr, ':');
       if(ptr_next) {
         curl_off_t port_to_match;
         if(!curlx_str_number(&ptr, &port_to_match, 0xffff) &&

diff --git a/lib/urlapi.c b/lib/urlapi.c
index 9899f6aff39ec209960ec52655bf4fc1505d2213..1cce6aaee24cd6ba0b96f957102954ef14801767 100644 (file)
--- a/lib/urlapi.c
+++ b/lib/urlapi.c
@@ -265,7 +265,7 @@ static CURLUcode parse_hostname_login(struct Curl_URL *u,
    *
    * We need somewhere to put the embedded details, so do that first.
    */
-  char *ptr;
+  const char *ptr;
 
   DEBUGASSERT(login);
 
@@ -577,7 +577,7 @@ static int ipv4_normalize(struct dynbuf *host)
 /* if necessary, replace the host content with a URL decoded version */
 static CURLUcode urldecode_host(struct dynbuf *host)
 {
-  char *per = NULL;
+  const char *per;
   const char *hostname = curlx_dyn_ptr(host);
   per = strchr(hostname, '%');
   if(!per)
@@ -780,8 +780,8 @@ UNITTEST int dedotdotify(const char *input, size_t clen, char **outp)
           /* remove the last segment from the output buffer */
           size_t len = curlx_dyn_len(&out);
           if(len) {
-            char *ptr = curlx_dyn_ptr(&out);
-            char *last = memrchr(ptr, '/', len);
+            const char *ptr = curlx_dyn_ptr(&out);
+            const char *last = memrchr(ptr, '/', len);
             if(last)
               /* trim the output at the slash */
               curlx_dyn_setlen(&out, last - ptr);

diff --git a/lib/vauth/vauth.c b/lib/vauth/vauth.c
index 112838b0ccafd307cc9e9a2cf3e4f5e1f7fd4ceb..bdf194b99562b3a8abda275fc77d1d9808992c52 100644 (file)
--- a/lib/vauth/vauth.c
+++ b/lib/vauth/vauth.c
@@ -117,7 +117,7 @@ bool Curl_auth_user_contains_domain(const char *user)
 
   if(user && *user) {
     /* Check we have a domain name or UPN present */
-    char *p = strpbrk(user, "\\/@");
+    const char *p = strpbrk(user, "\\/@");
 
     valid = (p != NULL && p > user && p < user + strlen(user) - 1);
   }

diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index aef51830876c0ff045c900d3858958a08541260b..b8dc9273ab74435c6639a43167e05af04e418cf4 100644 (file)
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -689,7 +689,7 @@ CURLcode Curl_ssl_random(struct Curl_easy *data,
 static CURLcode pubkey_pem_to_der(const char *pem,
                                   unsigned char **der, size_t *der_len)
 {
-  char *begin_pos, *end_pos;
+  const char *begin_pos, *end_pos;
   size_t pem_count, pem_len;
   CURLcode result;
   struct dynbuf pbuf;

diff --git a/src/tool_cb_hdr.c b/src/tool_cb_hdr.c
index 1381ffa317e596973d0c9fba9e4d86b0b825bd69..876a599049971f98761afdf2633b275e1c99f324 100644 (file)
--- a/src/tool_cb_hdr.c
+++ b/src/tool_cb_hdr.c
@@ -452,7 +452,7 @@ size_t tool_header_cb(char *ptr, size_t size, size_t nmemb, void *userdata)
     }
   }
   if(hdrcbdata->config->writeout) {
-    char *value = memchr(ptr, ':', cb);
+    const char *value = memchr(ptr, ':', cb);
     if(value) {
       if(per->was_last_header_empty)
         per->num_headers = 0;
@@ -466,7 +466,7 @@ size_t tool_header_cb(char *ptr, size_t size, size_t nmemb, void *userdata)
      (scheme == proto_http || scheme == proto_https ||
       scheme == proto_rtsp || scheme == proto_file)) {
     /* bold headers only for selected protocols */
-    char *value = NULL;
+    const char *value = NULL;
 
     if(!outs->stream && !tool_create_output_file(outs, per->config))
       return CURL_WRITEFUNC_ERROR;

diff --git a/src/tool_getparam.c b/src/tool_getparam.c
index a66f0447999797d42a6f15ed56823983dfcd907f..991e769d6879fd47d8e55dfbe71908010d9c2aa0 100644 (file)
--- a/src/tool_getparam.c
+++ b/src/tool_getparam.c
@@ -1673,7 +1673,7 @@ static ParameterError parse_upload_flags(struct OperationConfig *config,
     bool negate;
     const struct flagmap *map;
     size_t len;
-    char *next = strchr(flag, ','); /* Find next comma or end */
+    const char *next = strchr(flag, ','); /* Find next comma or end */
     if(next)
       len = next - flag;
     else

diff --git a/src/tool_operhlp.c b/src/tool_operhlp.c
index ac209b440a5d79d3422e3c0112f43f417473313d..db3365e7f154fbb300cd5808f55a80c7dbad7bf0 100644 (file)
--- a/src/tool_operhlp.c
+++ b/src/tool_operhlp.c
@@ -89,7 +89,7 @@ CURLcode add_file_name_to_url(CURL *curl, char **inurlp, const char *filename)
   char *path = NULL;
   char *query = NULL;
   if(uh) {
-    char *ptr;
+    const char *ptr;
     uerr = curl_url_set(uh, CURLUPART_URL, *inurlp,
                         CURLU_GUESS_SCHEME | CURLU_NON_SUPPORT_SCHEME);
     if(uerr) {

diff --git a/src/var.c b/src/var.c
index f796aa7ed76b630c560d31a21acfee8cf016a475..4cc1b640fa915f613ff8f0c5679e70687fc4374a 100644 (file)
--- a/src/var.c
+++ b/src/var.c
@@ -75,7 +75,7 @@ static const struct tool_var *varcontent(const char *name, size_t nlen)
 
 static ParameterError varfunc(char *c, /* content */
                               size_t clen, /* content length */
-                              char *f, /* functions */
+                              const char *f, /* functions */
                               size_t flen, /* function string length */
                               struct dynbuf *out)
 {
@@ -207,7 +207,7 @@ static ParameterError varfunc(char *c, /* content */
 ParameterError varexpand(const char *line, struct dynbuf *out, bool *replaced)
 {
   CURLcode result;
-  char *envp;
+  const char *envp;
   bool added = FALSE;
   const char *input = line;
   *replaced = FALSE;
@@ -232,8 +232,8 @@ ParameterError varexpand(const char *line, struct dynbuf *out, bool *replaced)
       char name[MAX_VAR_LEN];
       size_t nlen;
       size_t i;
-      char *funcp;
-      char *clp = strstr(envp, "}}");
+      const char *funcp;
+      const char *clp = strstr(envp, "}}");
       size_t prefix;
 
       if(!clp) {
@@ -304,7 +304,7 @@ ParameterError varexpand(const char *line, struct dynbuf *out, bool *replaced)
           if(value && vlen > 0) {
             /* A variable might contain null bytes. Such bytes cannot be shown
                using normal means, this is an error. */
-            char *nb = memchr(value, '\0', vlen);
+            const char *nb = memchr(value, '\0', vlen);
             if(nb) {
               errorf("variable contains null byte");
               return PARAM_EXPAND_ERROR;

diff --git a/tests/server/rtspd.c b/tests/server/rtspd.c
index b343c79bd4675542e6f2591c8f8cc4b07fbd1d80..c3878ea67a982a9b44df45c690ce51ee6d5138b1 100644 (file)
--- a/tests/server/rtspd.c
+++ b/tests/server/rtspd.c
@@ -149,7 +149,7 @@ static int rtspd_ProcessRequest(struct rtspd_httprequest *req)
   static char doc[MAXDOCNAMELEN];
   static char prot_str[5];
   int prot_major, prot_minor;
-  char *end = strstr(line, END_OF_HEADERS);
+  const char *end = strstr(line, END_OF_HEADERS);
 
   logmsg("rtspd_ProcessRequest() called with testno %ld and line [%s]",
          req->testno, line);
@@ -164,7 +164,7 @@ static int rtspd_ProcessRequest(struct rtspd_httprequest *req)
             prot_str,
             &prot_major,
             &prot_minor) == 5) {
-    char *ptr;
+    const char *ptr;
     const char *pval;
     curl_off_t testnum;
 
@@ -367,7 +367,7 @@ static int rtspd_ProcessRequest(struct rtspd_httprequest *req)
         else if(!strncmp(doc, "test", 4)) {
           /* if the hostname starts with test, the port number used in the
              CONNECT line will be used as test number! */
-          char *portp = strchr(doc, ':');
+          const char *portp = strchr(doc, ':');
           if(portp && (*(portp + 1) != '\0') && ISDIGIT(*(portp + 1))) {
             pval = portp + 1;
             if(!curlx_str_number(&pval, &testnum, INT_MAX))

diff --git a/tests/server/sws.c b/tests/server/sws.c
index 224cc9d888c0e6c47cb43522e53ac274a95e7598..43813c95f880cc35e5730262bef247ea4d765bcb 100644 (file)
--- a/tests/server/sws.c
+++ b/tests/server/sws.c
@@ -215,7 +215,7 @@ static int sws_parse_servercmd(struct sws_httprequest *req)
   }
   else {
     char *orgcmd = NULL;
-    char *cmd = NULL;
+    const char *cmd = NULL;
     size_t cmdsize = 0;
     int num = 0;
 
@@ -230,7 +230,7 @@ static int sws_parse_servercmd(struct sws_httprequest *req)
 
     cmd = orgcmd;
     while(cmd && cmdsize) {
-      char *check;
+      const char *check;
 
       if(!strncmp(CMD_AUTH_REQUIRED, cmd, strlen(CMD_AUTH_REQUIRED))) {
         logmsg("instructed to require authorization header");
@@ -308,7 +308,7 @@ static int sws_ProcessRequest(struct sws_httprequest *req)
   static char request[REQUEST_KEYWORD_SIZE];
   int prot_major = 0;
   int prot_minor = 0;
-  char *end = strstr(line, end_of_headers);
+  const char *end = strstr(line, end_of_headers);
   const char *pval;
   curl_off_t num;
 
@@ -329,7 +329,7 @@ static int sws_ProcessRequest(struct sws_httprequest *req)
   }
 
   else if(req->testno == DOCNUMBER_NOTHING) {
-    char *http;
+    const char *http;
     bool fine = FALSE;
     char *httppath = NULL;
     size_t npath = 0; /* httppath length */
@@ -512,7 +512,7 @@ static int sws_ProcessRequest(struct sws_httprequest *req)
   if(use_gopher) {
     /* when using gopher we cannot check the request until the entire
        thing has been received */
-    char *ptr;
+    const char *ptr;
 
     /* find the last slash in the line */
     ptr = strrchr(line, '/');

diff --git a/tests/server/tftpd.c b/tests/server/tftpd.c
index 1e0fcc9a48d793547ce691742f4323eca6b095d7..031e4cf2be8eaf9c746493d8e72017346fb0ae03 100644 (file)
--- a/tests/server/tftpd.c
+++ b/tests/server/tftpd.c
@@ -548,7 +548,7 @@ static int tftpd_parse_servercmd(struct testcase *req)
   }
   else {
     char *orgcmd = NULL;
-    char *cmd = NULL;
+    const char *cmd = NULL;
     size_t cmdsize = 0;
     int num = 0;
 
@@ -562,7 +562,7 @@ static int tftpd_parse_servercmd(struct testcase *req)
 
     cmd = orgcmd;
     while(cmd && cmdsize) {
-      char *check;
+      const char *check;
       if(sscanf(cmd, "writedelay: %d", &num) == 1) {
         logmsg("instructed to delay %d secs between packets", num);
         req->writedelay = num;
@@ -600,7 +600,7 @@ static int tftpd_parse_servercmd(struct testcase *req)
 static int validate_access(struct testcase *test,
                            const char *filename, unsigned short mode)
 {
-  char *ptr;
+  const char *ptr;
 
   logmsg("trying to get file: %s mode %x", filename, mode);
 

diff --git a/tests/unit/unit1652.c b/tests/unit/unit1652.c
index da0df33b4da149dcc1f7ef23e835bd2d3ea89599..a0780003654cd56f9f51617bb42894a06e60c73d 100644 (file)
--- a/tests/unit/unit1652.c
+++ b/tests/unit/unit1652.c
@@ -76,7 +76,7 @@ static void t1652_stop(struct Curl_easy *easy)
 static int verify(const char *info, const char *two)
 {
   /* the 'info' one has a newline appended */
-  char *nl = strchr(info, '\n');
+  const char *nl = strchr(info, '\n');
   if(!nl)
     return 1; /* nope */
   return strncmp(info, two, nl - info);