checksrc: warn for assignments within if() expressions

... they're already frowned upon in our source code style guide, this
now enforces the rule harder.

20 files changed, 140 insertions, 88 deletions

diff --git a/lib/checksrc.pl b/lib/checksrc.pl
index 022b193aa..c56e9c841 100755
--- a/lib/checksrc.pl
+++ b/lib/checksrc.pl
@@ -356,6 +356,14 @@ sub scanfile {
             }
         }
 
+        if($nostr =~ /^((.*)(if) *\()(.*)\)/) {
+            my $pos = length($1);
+            if($4 =~ / = /) {
+                checkwarn("ASSIGNWITHINCONDITION",
+                          $line, $pos+1, $file, $l,
+                          "assignment within conditional expression");
+            }
+        }
         # check spaces after open parentheses
         if($l =~ /^(.*[a-z])\( /i) {
             checkwarn("SPACEAFTERPAREN",
diff --git a/lib/cookie.c b/lib/cookie.c
index 24db9c6fe..092a226f3 100644
--- a/lib/cookie.c
+++ b/lib/cookie.c
@@ -798,8 +798,8 @@ Curl_cookie_add(struct Curl_easy *data,
   /* Check if the domain is a Public Suffix and if yes, ignore the cookie.
      This needs a libpsl compiled with builtin data. */
   if(domain && co->domain && !isip(co->domain)) {
-    if(((psl = psl_builtin()) != NULL)
-        && !psl_is_cookie_domain_acceptable(psl, domain, co->domain)) {
+    psl = psl_builtin();
+    if(psl && !psl_is_cookie_domain_acceptable(psl, domain, co->domain)) {
       infof(data,
             "cookie '%s' dropped, domain '%s' must not set cookies for '%s'\n",
             co->name, domain, co->domain);
diff --git a/lib/curl_addrinfo.c b/lib/curl_addrinfo.c
index c8ff83c79..61cdaddc1 100644
--- a/lib/curl_addrinfo.c
+++ b/lib/curl_addrinfo.c
@@ -146,7 +146,8 @@ Curl_getaddrinfo_ex(const char *nodename,
     if((size_t)ai->ai_addrlen < ss_size)
       continue;
 
-    if((ca = malloc(sizeof(Curl_addrinfo))) == NULL) {
+    ca = malloc(sizeof(Curl_addrinfo));
+    if(!ca) {
       error = EAI_MEMORY;
       break;
     }
@@ -163,7 +164,8 @@ Curl_getaddrinfo_ex(const char *nodename,
     ca->ai_canonname = NULL;
     ca->ai_next      = NULL;
 
-    if((ca->ai_addr = malloc(ss_size)) == NULL) {
+    ca->ai_addr = malloc(ss_size);
+    if(!ca->ai_addr) {
       error = EAI_MEMORY;
       free(ca);
       break;
@@ -171,7 +173,8 @@ Curl_getaddrinfo_ex(const char *nodename,
     memcpy(ca->ai_addr, ai->ai_addr, ss_size);
 
     if(ai->ai_canonname != NULL) {
-      if((ca->ai_canonname = strdup(ai->ai_canonname)) == NULL) {
+      ca->ai_canonname = strdup(ai->ai_canonname);
+      if(!ca->ai_canonname) {
         error = EAI_MEMORY;
         free(ca->ai_addr);
         free(ca);
@@ -291,16 +294,19 @@ Curl_he2ai(const struct hostent *he, int port)
 #endif
       ss_size = sizeof(struct sockaddr_in);
 
-    if((ai = calloc(1, sizeof(Curl_addrinfo))) == NULL) {
+    ai = calloc(1, sizeof(Curl_addrinfo));
+    if(!ai) {
       result = CURLE_OUT_OF_MEMORY;
       break;
     }
-    if((ai->ai_canonname = strdup(he->h_name)) == NULL) {
+    ai->ai_canonname = strdup(he->h_name);
+    if(!ai->ai_canonname) {
       result = CURLE_OUT_OF_MEMORY;
       free(ai);
       break;
     }
-    if((ai->ai_addr = calloc(1, ss_size)) == NULL) {
+    ai->ai_addr = calloc(1, ss_size);
+    if(!ai->ai_addr) {
       result = CURLE_OUT_OF_MEMORY;
       free(ai->ai_canonname);
       free(ai);
@@ -475,8 +481,9 @@ Curl_addrinfo *Curl_str2addr(char *address, int port)
 /**
  * Given a path to a Unix domain socket, return a newly allocated Curl_addrinfo
  * struct initialized with this path.
+ * Set '*longpath' to TRUE if the error is a too long path.
  */
-Curl_addrinfo *Curl_unix2addr(const char *path)
+Curl_addrinfo *Curl_unix2addr(const char *path, int *longpath)
 {
   Curl_addrinfo *ai;
   struct sockaddr_un *sa_un;
@@ -485,8 +492,10 @@ Curl_addrinfo *Curl_unix2addr(const char *path)
   ai = calloc(1, sizeof(Curl_addrinfo));
   if(!ai)
     return NULL;
-  if((ai->ai_addr = calloc(1, sizeof(struct sockaddr_un))) == NULL) {
+  ai->ai_addr = calloc(1, sizeof(struct sockaddr_un));
+  if(!ai->ai_addr) {
     free(ai);
+    *longpath = FALSE;
     return NULL;
   }
   /* sun_path must be able to store the NUL-terminated path */
@@ -494,6 +503,7 @@ Curl_addrinfo *Curl_unix2addr(const char *path)
   if(path_len >= sizeof(sa_un->sun_path)) {
     free(ai->ai_addr);
     free(ai);
+    *longpath = TRUE;
     return NULL;
   }
 
diff --git a/lib/curl_addrinfo.h b/lib/curl_addrinfo.h
index 1a681e61e..4f24730af 100644
--- a/lib/curl_addrinfo.h
+++ b/lib/curl_addrinfo.h
@@ -80,7 +80,7 @@ Curl_ip2addr(int af, const void *inaddr, const char *hostname, int port);
 Curl_addrinfo *Curl_str2addr(char *dotted, int port);
 
 #ifdef USE_UNIX_SOCKETS
-Curl_addrinfo *Curl_unix2addr(const char *path);
+Curl_addrinfo *Curl_unix2addr(const char *path, int *longpath);
 #endif
 
 #if defined(CURLDEBUG) && defined(HAVE_GETADDRINFO) && \
diff --git a/lib/curl_ntlm_wb.c b/lib/curl_ntlm_wb.c
index 4699d8f42..6a90e6236 100644
--- a/lib/curl_ntlm_wb.c
+++ b/lib/curl_ntlm_wb.c
@@ -157,7 +157,8 @@ static CURLcode ntlm_wb_init(struct connectdata *conn, const char *userp)
   }
   slash = strpbrk(username, "\\/");
   if(slash) {
-    if((domain = strdup(username)) == NULL)
+    domain = strdup(username);
+    if(!domain)
       return CURLE_OUT_OF_MEMORY;
     slash = domain + (slash - username);
     *slash = '\0';
diff --git a/lib/formdata.c b/lib/formdata.c
index 53dee39f4..abd2da075 100644
--- a/lib/formdata.c
+++ b/lib/formdata.c
@@ -949,8 +949,8 @@ void Curl_formclean(struct FormData **form_ptr)
     if(form->type <= FORM_CONTENT)
       free(form->line); /* free the line */
     free(form);       /* free the struct */
-
-  } while((form = next) != NULL); /* continue */
+    form = next;
+  } while(form); /* continue */
 
   *form_ptr = NULL;
 }
@@ -1031,8 +1031,8 @@ void curl_formfree(struct curl_httppost *form)
     free(form->contenttype); /* free the content type */
     free(form->showfilename); /* free the faked file name */
     free(form);       /* free the struct */
-
-  } while((form = next) != NULL); /* continue */
+    form = next;
+  } while(form); /* continue */
 }
 
 #ifndef HAVE_BASENAME
@@ -1374,8 +1374,8 @@ CURLcode Curl_getformdata(struct Curl_easy *data,
       if(result)
         break;
     }
-
-  } while((post = post->next) != NULL); /* for each field */
+    post = post->next;
+  } while(post); /* for each field */
 
   /* end-boundary for everything */
   if(!result)
diff --git a/lib/ftp.c b/lib/ftp.c
index 683f05de4..c7c275549 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -1035,7 +1035,8 @@ static CURLcode ftp_state_use_port(struct connectdata *conn,
     if(*string_ftpport == '[') {
       /* [ipv6]:port(-range) */
       ip_start = string_ftpport + 1;
-      if((ip_end = strchr(string_ftpport, ']')) != NULL)
+      ip_end = strchr(string_ftpport, ']');
+      if(ip_end)
         strncpy(addr, ip_start, ip_end - ip_start);
     }
     else
@@ -1043,30 +1044,35 @@ static CURLcode ftp_state_use_port(struct connectdata *conn,
       if(*string_ftpport == ':') {
         /* :port */
         ip_end = string_ftpport;
-    }
-    else if((ip_end = strchr(string_ftpport, ':')) != NULL) {
-        /* either ipv6 or (ipv4|domain|interface):port(-range) */
-#ifdef ENABLE_IPV6
-      if(Curl_inet_pton(AF_INET6, string_ftpport, sa6) == 1) {
-        /* ipv6 */
-        port_min = port_max = 0;
-        strcpy(addr, string_ftpport);
-        ip_end = NULL; /* this got no port ! */
       }
-      else
+      else {
+        ip_end = strchr(string_ftpport, ':');
+        if(ip_end) {
+          /* either ipv6 or (ipv4|domain|interface):port(-range) */
+#ifdef ENABLE_IPV6
+          if(Curl_inet_pton(AF_INET6, string_ftpport, sa6) == 1) {
+            /* ipv6 */
+            port_min = port_max = 0;
+            strcpy(addr, string_ftpport);
+            ip_end = NULL; /* this got no port ! */
+          }
+          else
 #endif
-        /* (ipv4|domain|interface):port(-range) */
-        strncpy(addr, string_ftpport, ip_end - ip_start);
-    }
-    else
-      /* ipv4|interface */
-      strcpy(addr, string_ftpport);
+            /* (ipv4|domain|interface):port(-range) */
+            strncpy(addr, string_ftpport, ip_end - ip_start);
+        }
+        else
+          /* ipv4|interface */
+          strcpy(addr, string_ftpport);
+      }
 
     /* parse the port */
     if(ip_end != NULL) {
-      if((port_start = strchr(ip_end, ':')) != NULL) {
+      port_start = strchr(ip_end, ':');
+      if(port_start) {
         port_min = curlx_ultous(strtoul(port_start+1, NULL, 10));
-        if((port_sep = strchr(port_start, '-')) != NULL) {
+        port_sep = strchr(port_start, '-');
+        if(port_sep) {
           port_max = curlx_ultous(strtoul(port_sep + 1, NULL, 10));
         }
         else
diff --git a/lib/http.c b/lib/http.c
index fba33d8e6..4c1c07fe7 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -840,9 +840,11 @@ CURLcode Curl_http_input_auth(struct connectdata *conn, bool proxy,
                   auth += strlen("NTLM");
                   while(*auth && ISSPACE(*auth))
                     auth++;
-                  if(*auth)
-                    if((conn->challenge_header = strdup(auth)) == NULL)
+                  if(*auth) {
+                    conn->challenge_header = strdup(auth);
+                    if(!conn->challenge_header)
                       return CURLE_OUT_OF_MEMORY;
+                  }
                 }
               }
 #endif
diff --git a/lib/http_digest.c b/lib/http_digest.c
index 91b88a383..0ed02493d 100644
--- a/lib/http_digest.c
+++ b/lib/http_digest.c
@@ -75,7 +75,7 @@ CURLcode Curl_output_digest(struct connectdata *conn,
   CURLcode result;
   struct Curl_easy *data = conn->data;
   unsigned char *path;
-  char *tmp;
+  char *tmp = NULL;
   char *response;
   size_t len;
   bool have_chlg;
@@ -140,12 +140,14 @@ CURLcode Curl_output_digest(struct connectdata *conn,
      http://www.fngtps.com/2006/09/http-authentication
   */
 
-  if(authp->iestyle && ((tmp = strchr((char *)uripath, '?')) != NULL)) {
-    size_t urilen = tmp - (char *)uripath;
-
-    path = (unsigned char *) aprintf("%.*s", urilen, uripath);
+  if(authp->iestyle) {
+    tmp = strchr((char *)uripath, '?');
+    if(tmp) {
+      size_t urilen = tmp - (char *)uripath;
+      path = (unsigned char *) aprintf("%.*s", urilen, uripath);
+    }
   }
-  else
+  if(!tmp)
     path = (unsigned char *) strdup((char *) uripath);
 
   if(!path)
diff --git a/lib/inet_pton.c b/lib/inet_pton.c
index bff8ddadd..475f44abc 100644
--- a/lib/inet_pton.c
+++ b/lib/inet_pton.c
@@ -103,7 +103,8 @@ inet_pton4(const char *src, unsigned char *dst)
   while((ch = *src++) != '\0') {
     const char *pch;
 
-    if((pch = strchr(digits, ch)) != NULL) {
+    pch = strchr(digits, ch);
+    if(pch) {
       unsigned int val = *tp * 10 + (unsigned int)(pch - digits);
 
       if(saw_digit && *tp == 0)
@@ -169,7 +170,8 @@ inet_pton6(const char *src, unsigned char *dst)
   while((ch = *src++) != '\0') {
     const char *pch;
 
-    if((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
+    pch = strchr((xdigits = xdigits_l), ch);
+    if(!pch)
       pch = strchr((xdigits = xdigits_u), ch);
     if(pch != NULL) {
       val <<= 4;
diff --git a/lib/md4.c b/lib/md4.c
index 60f73a28b..1bdc9f367 100644
--- a/lib/md4.c
+++ b/lib/md4.c
@@ -213,7 +213,8 @@ static void MD4_Update(MD4_CTX *ctx, const void *data, unsigned long size)
   unsigned long used, available;
 
   saved_lo = ctx->lo;
-  if((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
+  ctx->lo = (saved_lo + size) & 0x1fffffff;
+  if(ctx->lo < saved_lo)
     ctx->hi++;
   ctx->hi += (MD4_u32plus)size >> 29;
 
diff --git a/lib/md5.c b/lib/md5.c
index 7a1cac902..f2dc16c09 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -402,7 +402,8 @@ static void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size)
   unsigned long used, available;
 
   saved_lo = ctx->lo;
-  if((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
+  ctx->lo = (saved_lo + size) & 0x1fffffff;
+  if(ctx->lo < saved_lo)
     ctx->hi++;
   ctx->hi += (MD5_u32plus)size >> 29;
 
diff --git a/lib/nwlib.c b/lib/nwlib.c
index 27e33e472..290cbe31f 100644
--- a/lib/nwlib.c
+++ b/lib/nwlib.c
@@ -184,7 +184,8 @@ int GetOrSetUpData(int id, libdata_t **appData,
      */
     NXLock(gLibLock);
 
-    if(!(app_data = (libdata_t *) get_app_data(id))) {
+    app_data = (libdata_t *) get_app_data(id);
+    if(!app_data) {
       app_data = malloc(sizeof(libdata_t));
 
       if(app_data) {
@@ -259,7 +260,8 @@ int GetOrSetUpData(int id, libdata_t **appData,
           err         = ENOMEM;
         }
 
-        if((err = NXKeySetValue(key, thread_data))) {
+        err = NXKeySetValue(key, thread_data);
+        if(err) {
           free(thread_data->twentybytes);
           free(thread_data);
           thread_data = (libthreaddata_t *) NULL;
diff --git a/lib/ssh.c b/lib/ssh.c
index 80831dbfa..9b014a4ff 100644
--- a/lib/ssh.c
+++ b/lib/ssh.c
@@ -782,14 +782,14 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
           state(conn, SSH_AUTH_DONE);
           break;
         }
-        else if((err = libssh2_session_last_errno(sshc->ssh_session)) ==
-           LIBSSH2_ERROR_EAGAIN) {
-          rc = LIBSSH2_ERROR_EAGAIN;
-          break;
-        }
         else {
-          state(conn, SSH_SESSION_FREE);
-          sshc->actualcode = libssh2_session_error_to_CURLE(err);
+          err = libssh2_session_last_errno(sshc->ssh_session);
+          if(err == LIBSSH2_ERROR_EAGAIN)
+            rc = LIBSSH2_ERROR_EAGAIN;
+          else {
+            state(conn, SSH_SESSION_FREE);
+            sshc->actualcode = libssh2_session_error_to_CURLE(err);
+          }
           break;
         }
       }
@@ -1987,12 +1987,14 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
           break;
         }
       }
-      if((sshc->readdir_filename = malloc(PATH_MAX+1)) == NULL) {
+      sshc->readdir_filename = malloc(PATH_MAX+1);
+      if(!sshc->readdir_filename) {
         state(conn, SSH_SFTP_CLOSE);
         sshc->actualcode = CURLE_OUT_OF_MEMORY;
         break;
       }
-      if((sshc->readdir_longentry = malloc(PATH_MAX+1)) == NULL) {
+      sshc->readdir_longentry = malloc(PATH_MAX+1);
+      if(!sshc->readdir_longentry) {
         Curl_safefree(sshc->readdir_filename);
         state(conn, SSH_SFTP_CLOSE);
         sshc->actualcode = CURLE_OUT_OF_MEMORY;
@@ -2789,13 +2791,16 @@ static int ssh_getsock(struct connectdata *conn,
 static void ssh_block2waitfor(struct connectdata *conn, bool block)
 {
   struct ssh_conn *sshc = &conn->proto.sshc;
-  int dir;
-  if(block && (dir = libssh2_session_block_directions(sshc->ssh_session))) {
-    /* translate the libssh2 define bits into our own bit defines */
-    conn->waitfor = ((dir&LIBSSH2_SESSION_BLOCK_INBOUND)?KEEP_RECV:0) |
-      ((dir&LIBSSH2_SESSION_BLOCK_OUTBOUND)?KEEP_SEND:0);
+  int dir = 0;
+  if(block) {
+    dir = libssh2_session_block_directions(sshc->ssh_session);
+    if(dir) {
+      /* translate the libssh2 define bits into our own bit defines */
+      conn->waitfor = ((dir&LIBSSH2_SESSION_BLOCK_INBOUND)?KEEP_RECV:0) |
+        ((dir&LIBSSH2_SESSION_BLOCK_OUTBOUND)?KEEP_SEND:0);
+    }
   }
-  else
+  if(!dir)
     /* It didn't block or libssh2 didn't reveal in which direction, put back
        the original set */
     conn->waitfor = sshc->orig_waitfor;
diff --git a/lib/strerror.c b/lib/strerror.c
index 8f8ce036c..7e5cde47b 100644
--- a/lib/strerror.c
+++ b/lib/strerror.c
@@ -715,10 +715,12 @@ const char *Curl_strerror(struct connectdata *conn, int err)
   buf[max] = '\0'; /* make sure the string is zero terminated */
 
   /* strip trailing '\r\n' or '\n'. */
-  if((p = strrchr(buf, '\n')) != NULL && (p - buf) >= 2)
-     *p = '\0';
-  if((p = strrchr(buf, '\r')) != NULL && (p - buf) >= 1)
-     *p = '\0';
+  p = strrchr(buf, '\n');
+  if(p && (p - buf) >= 2)
+    *p = '\0';
+  p = strrchr(buf, '\r');
+  if(p && (p - buf) >= 1)
+    *p = '\0';
 
   if(old_errno != ERRNO)
     SET_ERRNO(old_errno);
@@ -1035,10 +1037,12 @@ const char *Curl_sspi_strerror (struct connectdata *conn, int err)
     if(msg_formatted) {
       msgbuf[sizeof(msgbuf)-1] = '\0';
       /* strip trailing '\r\n' or '\n' */
-      if((p = strrchr(msgbuf, '\n')) != NULL && (p - msgbuf) >= 2)
-         *p = '\0';
-      if((p = strrchr(msgbuf, '\r')) != NULL && (p - msgbuf) >= 1)
-         *p = '\0';
+      p = strrchr(msgbuf, '\n');
+      if(p && (p - msgbuf) >= 2)
+        *p = '\0';
+      p = strrchr(msgbuf, '\r');
+      if(p && (p - msgbuf) >= 1)
+        *p = '\0';
       msg = msgbuf;
     }
     if(msg)
diff --git a/lib/telnet.c b/lib/telnet.c
index 935cde35b..551af60f2 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -1489,7 +1489,8 @@ static CURLcode telnet_do(struct connectdata *conn, bool *done)
 
       events.lNetworkEvents = 0;
       if(SOCKET_ERROR == enum_netevents_func(sockfd, event_handle, &events)) {
-        if((err = SOCKERRNO) != EINPROGRESS) {
+        err = SOCKERRNO;
+        if(err != EINPROGRESS) {
           infof(data, "WSAEnumNetworkEvents failed (%d)", err);
           keepon = FALSE;
           result = CURLE_READ_ERROR;
diff --git a/lib/url.c b/lib/url.c
index acdda6313..45262d897 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -5822,18 +5822,22 @@ static CURLcode resolve_server(struct Curl_easy *data,
       hostaddr = calloc(1, sizeof(struct Curl_dns_entry));
       if(!hostaddr)
         result = CURLE_OUT_OF_MEMORY;
-      else if((hostaddr->addr = Curl_unix2addr(path)) != NULL)
-        hostaddr->inuse++;
       else {
-        /* Long paths are not supported for now */
-        if(strlen(path) >= sizeof(((struct sockaddr_un *)0)->sun_path)) {
-          failf(data, "Unix socket path too long: '%s'", path);
-          result = CURLE_COULDNT_RESOLVE_HOST;
+        int longpath=0;
+        hostaddr->addr = Curl_unix2addr(path, &longpath);
+        if(hostaddr->addr)
+          hostaddr->inuse++;
+        else {
+          /* Long paths are not supported for now */
+          if(longpath) {
+            failf(data, "Unix socket path too long: '%s'", path);
+            result = CURLE_COULDNT_RESOLVE_HOST;
+          }
+          else
+            result = CURLE_OUT_OF_MEMORY;
+          free(hostaddr);
+          hostaddr = NULL;
         }
-        else
-          result = CURLE_OUT_OF_MEMORY;
-        free(hostaddr);
-        hostaddr = NULL;
       }
     }
     else
diff --git a/lib/vtls/gtls.c b/lib/vtls/gtls.c
index 1435284b8..0e308cb79 100644
--- a/lib/vtls/gtls.c
+++ b/lib/vtls/gtls.c
@@ -242,7 +242,8 @@ static gnutls_datum_t load_file(const char *file)
   long filelen;
   void *ptr;
 
-  if(!(f = fopen(file, "rb")))
+  f = fopen(file, "rb");
+  if(!f)
     return loaded_file;
   if(fseek(f, 0, SEEK_END) != 0
      || (filelen = ftell(f)) < 0
diff --git a/lib/vtls/nss.c b/lib/vtls/nss.c
index 455bad641..ba8d58260 100644
--- a/lib/vtls/nss.c
+++ b/lib/vtls/nss.c
@@ -254,7 +254,8 @@ static SECStatus set_ciphers(struct Curl_easy *data, PRFileDesc * model,
     while((*cipher) && (ISSPACE(*cipher)))
       ++cipher;
 
-    if((cipher_list = strchr(cipher, ','))) {
+    cipher_list = strchr(cipher, ',');
+    if(cipher_list) {
       *cipher_list++ = '\0';
     }
 
diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index 75051d41e..94410df4b 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -2336,7 +2336,8 @@ static int asn1_object_dump(ASN1_OBJECT *a, char *buf, size_t len)
 {
   int i, ilen;
 
-  if((ilen = (int)len) < 0)
+  ilen = (int)len;
+  if(ilen < 0)
     return 1; /* buffer too big */
 
   i = i2t_ASN1_OBJECT(buf, ilen, a);