Introduce virFilePrintf() as a portable fprintf()

We can't use GNULIB's fprintf-posix due to licensing
incompatibilities. We do already have a portable
formatting via virAsprintf() which we got from GNULIB
though. We can use to create a virFilePrintf() function.

But really gnulib could just provide a 'fprintf'
module, that depended on just its 'asprintf' module.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/libvirt_private.syms

@@ -1305,6 +1305,7 @@ virFileMatchesNameSuffix;
 virFileNBDDeviceAssociate;
 virFileOpenAs;
 virFileOpenTty;
+virFilePrintf;
 virFileReadAll;
 virFileReadLimFD;
 virFileResolveAllLinks;

src/util/virfile.c

@@ -2318,3 +2318,37 @@ virFileSanitizePath(const char *path)
 
     return cleanpath;
 }
+
+
+/**
+ * virFilePrintf:
+ *
+ * A replacement for fprintf() which uses virVasprintf to
+ * ensure that portable string format placeholders can be
+ * used, since gnulib's fprintf() replacement is not
+ * LGPLV2+ compatible
+ */
+int virFilePrintf(FILE *fp, const char *msg, ...)
+{
+    va_list vargs;
+    char *str;
+    int ret;
+
+    va_start(vargs, msg);
+
+    if ((ret = virVasprintf(&str, msg, vargs)) < 0)
+        goto cleanup;
+
+    if (fwrite(str, 1, ret, fp) != ret) {
+        virReportSystemError(errno, "%s",
+                             _("Could not write to stream"));
+        ret = -1;
+    }
+
+    VIR_FREE(str);
+
+cleanup:
+    va_end(vargs);
+
+    return ret;
+}

src/util/virfile.h

@@ -229,4 +229,7 @@ void virFileWaitForDevices(void);
     virBuildPathInternal(path, __VA_ARGS__, NULL)
 int virBuildPathInternal(char **path, ...) ATTRIBUTE_SENTINEL;
 
+int virFilePrintf(FILE *fp, const char *msg, ...)
+    ATTRIBUTE_FMT_PRINTF(2, 3);
+
 #endif /* __VIR_FILE_H */

tests/fdstreamtest.c

@@ -105,16 +105,16 @@ static int testFDStreamReadCommon(const char *scratchdir, bool blocking)
                     usleep(20 * 1000);
                     goto reread;
                 }
-                fprintf(stderr, "Failed to read stream: %s\n",
-                        virGetLastErrorMessage());
+                virFilePrintf(stderr, "Failed to read stream: %s\n",
+                              virGetLastErrorMessage());
                 goto cleanup;
             }
             if (got == 0) {
                 /* Expect EOF 1/2 through last pattern */
                 if (i == 9 && want == (PATTERN_LEN / 2))
                     break;
-                fprintf(stderr, "Unexpected EOF block %zu want %zu\n",
-                        i, want);
+                virFilePrintf(stderr, "Unexpected EOF block %zu want %zu\n",
+                              i, want);
                 goto cleanup;
             }
             offset += got;
@@ -122,25 +122,25 @@ static int testFDStreamReadCommon(const char *scratchdir, bool blocking)
         }
         if (i == 0) {
             if (memcmp(buf, pattern + (PATTERN_LEN / 2), PATTERN_LEN / 2) != 0) {
-                fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                 goto cleanup;
             }
         } else if (i == 9) {
             if (memcmp(buf, pattern, PATTERN_LEN / 2) != 0) {
-                fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                 goto cleanup;
             }
         } else {
             if (memcmp(buf, pattern, PATTERN_LEN) != 0) {
-                fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                 goto cleanup;
             }
         }
     }
 
     if (st->driver->streamFinish(st) != 0) {
-        fprintf(stderr, "Failed to finish stream: %s\n",
-                virGetLastErrorMessage());
+        virFilePrintf(stderr, "Failed to finish stream: %s\n",
+                      virGetLastErrorMessage());
         goto cleanup;
     }
 
@@ -229,8 +229,8 @@ static int testFDStreamWriteCommon(const char *scratchdir, bool blocking)
                 if (i == 9 &&
                     want == (PATTERN_LEN / 2))
                     break;
-                fprintf(stderr, "Failed to write stream: %s\n",
-                        virGetLastErrorMessage());
+                virFilePrintf(stderr, "Failed to write stream: %s\n",
+                              virGetLastErrorMessage());
                 goto cleanup;
             }
             offset += got;
@@ -239,8 +239,8 @@ static int testFDStreamWriteCommon(const char *scratchdir, bool blocking)
     }
 
     if (st->driver->streamFinish(st) != 0) {
-        fprintf(stderr, "Failed to finish stream: %s\n",
-                virGetLastErrorMessage());
+        virFilePrintf(stderr, "Failed to finish stream: %s\n",
+                      virGetLastErrorMessage());
         goto cleanup;
    }
 
@@ -255,7 +255,7 @@ static int testFDStreamWriteCommon(const char *scratchdir, bool blocking)
             want = PATTERN_LEN;
 
         if (saferead(fd, buf, want) != want) {
-            fprintf(stderr, "Short read from data\n");
+            virFilePrintf(stderr, "Short read from data\n");
             goto cleanup;
         }
 
@@ -263,22 +263,22 @@ static int testFDStreamWriteCommon(const char *scratchdir, bool blocking)
             size_t j;
             for (j = 0; j < (PATTERN_LEN / 2); j++) {
                 if (buf[j] != 0) {
-                    fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                    virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                     goto cleanup;
                 }
             }
             if (memcmp(buf + (PATTERN_LEN / 2), pattern, PATTERN_LEN / 2) != 0) {
-                fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                 goto cleanup;
             }
         } else if (i == 9) {
             if (memcmp(buf, pattern, PATTERN_LEN / 2) != 0) {
-                fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                 goto cleanup;
             }
         } else {
             if (memcmp(buf, pattern, PATTERN_LEN) != 0) {
-                fprintf(stderr, "Mismatched pattern data iteration %zu\n", i);
+                virFilePrintf(stderr, "Mismatched pattern data iteration %zu\n", i);
                 goto cleanup;
             }
         }
@@ -324,7 +324,7 @@ mymain(void)
     virFDStreamSetIOHelper(iohelper);
 
     if (!mkdtemp(scratchdir)) {
-        fprintf(stderr, "Cannot create fakesysfsdir");
+        virFilePrintf(stderr, "Cannot create fakesysfsdir");
         abort();
     }
 

tests/virstringtest.c

@@ -25,8 +25,8 @@
 #include "testutils.h"
 #include "virerror.h"
 #include "viralloc.h"
+#include "virfile.h"
 #include "virlog.h"
-
 #include "virstring.h"
 
 #define VIR_FROM_THIS VIR_FROM_NONE
@@ -62,18 +62,18 @@ static int testSplit(const void *args)
     tmp2 = data->tokens;
     while (*tmp1 && *tmp2) {
         if (STRNEQ(*tmp1, *tmp2)) {
-            fprintf(stderr, "Mismatch '%s' vs '%s'\n", *tmp1, *tmp2);
+            virFilePrintf(stderr, "Mismatch '%s' vs '%s'\n", *tmp1, *tmp2);
             goto cleanup;
         }
         tmp1++;
         tmp2++;
     }
     if (*tmp1) {
-        fprintf(stderr, "Too many pieces returned\n");
+        virFilePrintf(stderr, "Too many pieces returned\n");
         goto cleanup;
     }
     if (*tmp2) {
-        fprintf(stderr, "Too few pieces returned\n");
+        virFilePrintf(stderr, "Too few pieces returned\n");
         goto cleanup;
     }
 
@@ -96,7 +96,7 @@ static int testJoin(const void *args)
         return -1;
     }
     if (STRNEQ(got, data->string)) {
-        fprintf(stderr, "Mismatch '%s' vs '%s'\n", got, data->string);
+        virFilePrintf(stderr, "Mismatch '%s' vs '%s'\n", got, data->string);
         goto cleanup;
     }
 
@@ -143,49 +143,49 @@ testStrdup(const void *data ATTRIBUTE_UNUSED)
 
     value = VIR_STRDUP(array[i++], testStrdupLookup1(j++));
     if (value != 1) {
-        fprintf(stderr, "unexpected strdup result %d, expected 1\n", value);
+        virFilePrintf(stderr, "unexpected strdup result %d, expected 1\n", value);
         goto cleanup;
     }
     if (i != 1) {
-        fprintf(stderr, "unexpected side effects i=%zu, expected 1\n", i);
+        virFilePrintf(stderr, "unexpected side effects i=%zu, expected 1\n", i);
         goto cleanup;
     }
     if (j != 1) {
-        fprintf(stderr, "unexpected side effects j=%zu, expected 1\n", j);
+        virFilePrintf(stderr, "unexpected side effects j=%zu, expected 1\n", j);
         goto cleanup;
     }
     if (STRNEQ_NULLABLE(array[0], "hello") || array[1]) {
-        fprintf(stderr, "incorrect array contents '%s' '%s'\n",
-                NULLSTR(array[0]), NULLSTR(array[1]));
+        virFilePrintf(stderr, "incorrect array contents '%s' '%s'\n",
+                      NULLSTR(array[0]), NULLSTR(array[1]));
         goto cleanup;
     }
 
     value = VIR_STRNDUP(array[i++], testStrdupLookup1(j++),
                         testStrdupLookup2(k++));
     if (value != 0) {
-        fprintf(stderr, "unexpected strdup result %d, expected 0\n", value);
+        virFilePrintf(stderr, "unexpected strdup result %d, expected 0\n", value);
         goto cleanup;
     }
     if (i != 2) {
-        fprintf(stderr, "unexpected side effects i=%zu, expected 2\n", i);
+        virFilePrintf(stderr, "unexpected side effects i=%zu, expected 2\n", i);
         goto cleanup;
     }
     if (j != 2) {
-        fprintf(stderr, "unexpected side effects j=%zu, expected 2\n", j);
+        virFilePrintf(stderr, "unexpected side effects j=%zu, expected 2\n", j);
         goto cleanup;
     }
     if (k != 1) {
-        fprintf(stderr, "unexpected side effects k=%zu, expected 1\n", k);
+        virFilePrintf(stderr, "unexpected side effects k=%zu, expected 1\n", k);
         goto cleanup;
     }
     if (STRNEQ_NULLABLE(array[0], "hello") || array[1]) {
-        fprintf(stderr, "incorrect array contents '%s' '%s'\n",
-                NULLSTR(array[0]), NULLSTR(array[1]));
+        virFilePrintf(stderr, "incorrect array contents '%s' '%s'\n",
+                      NULLSTR(array[0]), NULLSTR(array[1]));
         goto cleanup;
     }
 
     if (fail) {
-        fprintf(stderr, "side effects failed\n");
+        virFilePrintf(stderr, "side effects failed\n");
         goto cleanup;
     }