tool: change some fopen failures from warnings to errors

- Error on missing input file for --data, --data-binary,
  --data-urlencode, --header, --variable, --write-out.

Prior to this change if a user of the curl tool specified an input file
for one of the above options and that file could not be opened then it
would be treated as zero length data instead of an error. For example, a
POST using `--data @filenametypo` would cause a zero length POST which
is probably not what the user intended.

Closes https://github.com/curl/curl/pull/11677

src/tool_getparam.c

@@ -609,10 +609,10 @@ static ParameterError data_urlencode(struct GlobalConfig *global,
     }
     else {
       file = fopen(p, "rb");
-      if(!file)
-        warnf(global,
-              "Couldn't read data from file \"%s\", this makes "
-              "an empty POST.", nextarg);
+      if(!file) {
+        errorf(global, "Failed to open %s", p);
+        return PARAM_READ_ERROR;
+      }
     }
 
     err = file2memory(&postdata, &size, file);
@@ -1761,9 +1761,11 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
         }
         else {
           file = fopen(nextarg, "rb");
-          if(!file)
-            warnf(global, "Couldn't read data from file \"%s\", this makes "
-                  "an empty POST.", nextarg);
+          if(!file) {
+            errorf(global, "Failed to open %s", nextarg);
+            err = PARAM_READ_ERROR;
+            break;
+          }
         }
 
         if((subletter == 'b') || /* --data-binary */
@@ -2195,8 +2197,11 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
         size_t len;
         bool use_stdin = !strcmp(&nextarg[1], "-");
         FILE *file = use_stdin?stdin:fopen(&nextarg[1], FOPEN_READTEXT);
-        if(!file)
-          warnf(global, "Failed to open %s", &nextarg[1]);
+        if(!file) {
+          errorf(global, "Failed to open %s", &nextarg[1]);
+          err = PARAM_READ_ERROR;
+          break;
+        }
         else {
           err = file2memory(&string, &len, file);
           if(!err && string) {
@@ -2544,7 +2549,12 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
         }
         else {
           fname = nextarg;
-          file = fopen(nextarg, FOPEN_READTEXT);
+          file = fopen(fname, FOPEN_READTEXT);
+          if(!file) {
+            errorf(global, "Failed to open %s", fname);
+            err = PARAM_READ_ERROR;
+            break;
+          }
         }
         Curl_safefree(config->writeout);
         err = file2string(&config->writeout, file);

src/var.c

@@ -431,12 +431,14 @@ ParameterError setvariable(struct GlobalConfig *global,
       file = stdin;
     else {
       file = fopen(line, "rb");
+      if(!file) {
+        errorf(global, "Failed to open %s", line);
+        return PARAM_READ_ERROR;
+      }
     }
-    if(file) {
-      err = file2memory(&content, &clen, file);
-      /* in case of out of memory, this should fail the entire operation */
-      contalloc = TRUE;
-    }
+    err = file2memory(&content, &clen, file);
+    /* in case of out of memory, this should fail the entire operation */
+    contalloc = TRUE;
     if(!use_stdin)
       fclose(file);
     if(err)

tests/data/Makefile.inc

@@ -51,7 +51,7 @@ test226 test227 test228 test229 test230 test231 test232 test233 test234 \
 test235 test236 test237 test238 test239 test240 test241 test242 test243 \
 test244 test245 test246 test247 test248 test249 test250 test251 test252 \
 test253 test254 test255 test256 test257 test258 test259 test260 test261 \
-test262 test263 test264 test265 test266 test267 test268 test269 test270 \
+test262 test263 test264 test265 test266 test267 test269 test270 \
 test271 test272 test273 test274 test275 test276 test277 test278 test279 \
 test280 test281 test282 test283 test284 test285 test286 test287 test288 \
 test289 test290 test291 test292 test293 test294 test295 test296 test297 \

tests/data/test268

@@ -1,55 +0,0 @@
-<testcase>
-<info>
-<keywords>
-HTTP
-HTTP POST
-</keywords>
-</info>
-#
-# Server-side
-<reply>
-<data>
-HTTP/1.0 200 OK
-Server: test-server/fake
-Content-Type: text/html
-Content-Length: 0
-
-this is data even though Content-Length is set to zero
-</data>
-<datacheck>
-HTTP/1.0 200 OK
-Server: test-server/fake
-Content-Type: text/html
-Content-Length: 0
-
-</datacheck>
-</reply>
-
-#
-# Client-side
-<client>
-<server>
-http
-</server>
- <name>
-HTTP POST a non-existing file
- </name>
- <command>
- -d @nonesuchfile http://%HOSTIP:%HTTPPORT/%TESTNUMBER
-</command>
-</client>
-
-#
-# Verify data after the test has been "shot"
-<verify>
-<protocol>
-POST /%TESTNUMBER HTTP/1.1
-Host: %HOSTIP:%HTTPPORT
-User-Agent: curl/%VERSION
-Accept: */*
-Content-Length: 0
-Content-Type: application/x-www-form-urlencoded
-
-</protocol>
-</verify>
-</testcase>