util: replace strerror/strerror_r with g_strerror

g_strerror is offers the safety/correctness benefits of strerror_r, with
the API design convenience of strerror.

Use of virStrerror should be eliminated through the codebase in favour
of g_strerror.

commandhelper.c is a special case as its a tiny single threaded test
program, not linked to glib, so it just uses traditional strerror().

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

bootstrap.conf

@@ -79,8 +79,6 @@ snprintf
 socket
 stat-time
 strchrnul
-strerror
-strerror_r-posix
 strptime
 strsep
 strtok_r

docs/hacking.html.in

@@ -1051,6 +1051,10 @@ BAD:
       <dd>The GLib macros g_autoptr and G_DEFINE_AUTOPTR_CLEANUP_FUNC
         should be used to manage autoclean of virObject classes.
         This matches usage with GObject classes.</dd>
+
+      <dt>virStrerror</dt>
+      <dd>The GLib g_strerror() function should be used instead,
+        which has a simpler calling convention as an added benefit.</dd>
     </dl>
 
     <h2><a id="file_handling">File handling</a></h2>

src/util/virerror.c

@@ -1322,8 +1322,11 @@ const char *virStrerror(int theerrno, char *errBuf, size_t errBufLen)
 {
     int save_errno = errno;
     const char *ret;
+    const char *str = g_strerror(theerrno);
+    size_t len = strlen(str);
 
-    strerror_r(theerrno, errBuf, errBufLen);
+    memcpy(errBuf, str, MIN(len, errBufLen));
+    errBuf[errBufLen-1] = '\0';
     ret = errBuf;
     errno = save_errno;
     return ret;
@@ -1349,11 +1352,9 @@ void virReportSystemErrorFull(int domcode,
                               const char *fmt, ...)
 {
     int save_errno = errno;
-    char strerror_buf[VIR_ERROR_MAX_LENGTH];
     char msgDetailBuf[VIR_ERROR_MAX_LENGTH];
 
-    const char *errnoDetail = virStrerror(theerrno, strerror_buf,
-                                          sizeof(strerror_buf));
+    const char *errnoDetail = g_strerror(theerrno);
     const char *msg = virErrorMsg(VIR_ERR_SYSTEM_ERROR, fmt);
     const char *msgDetail = NULL;
 

src/util/virerror.h

@@ -193,6 +193,7 @@ void virReportOOMErrorFull(int domcode,
 int virSetError(virErrorPtr newerr);
 virErrorPtr virErrorCopyNew(virErrorPtr err);
 void virDispatchError(virConnectPtr conn);
+/* DEPRECATED: use g_strerror() directly */
 const char *virStrerror(int theerrno, char *errBuf, size_t errBufLen);
 
 typedef int (*virErrorLogPriorityFunc)(virErrorPtr, int);

tests/commandtest.c

@@ -636,12 +636,12 @@ static int test16(const void *unused ATTRIBUTE_UNUSED)
     }
     if ((fd = open(abs_builddir "/commandhelper.log",
                    O_CREAT | O_TRUNC | O_WRONLY, 0600)) < 0) {
-        printf("Cannot open log file: %s\n", strerror(errno));
+        printf("Cannot open log file: %s\n", g_strerror(errno));
         goto cleanup;
     }
     virCommandWriteArgLog(cmd, fd);
     if (VIR_CLOSE(fd) < 0) {
-        printf("Cannot close log file: %s\n", strerror(errno));
+        printf("Cannot close log file: %s\n", g_strerror(errno));
         goto cleanup;
     }
 
@@ -1116,12 +1116,12 @@ static int test26(const void *unused ATTRIBUTE_UNUSED)
     }
     if ((fd = open(abs_builddir "/commandhelper.log",
                    O_CREAT | O_TRUNC | O_WRONLY, 0600)) < 0) {
-        printf("Cannot open log file: %s\n", strerror(errno));
+        printf("Cannot open log file: %s\n", g_strerror(errno));
         goto cleanup;
     }
     virCommandWriteArgLog(cmd, fd);
     if (VIR_CLOSE(fd) < 0) {
-        printf("Cannot close log file: %s\n", strerror(errno));
+        printf("Cannot close log file: %s\n", g_strerror(errno));
         goto cleanup;
     }
 
@@ -1186,7 +1186,7 @@ static int test27(const void *unused ATTRIBUTE_UNUSED)
     }
 
     if (pipe(pipe1) < 0 || pipe(pipe2) < 0) {
-        printf("Could not create pipe: %s\n", strerror(errno));
+        printf("Could not create pipe: %s\n", g_strerror(errno));
         goto cleanup;
     }
 

tests/qemumonitortestutils.c

@@ -417,7 +417,7 @@ qemuMonitorTestFree(qemuMonitorTestPtr test)
     VIR_FREE(test->items);
 
     if (test->tmpdir && rmdir(test->tmpdir) < 0)
-        VIR_WARN("Failed to remove tempdir: %s", strerror(errno));
+        VIR_WARN("Failed to remove tempdir: %s", g_strerror(errno));
 
     VIR_FREE(test->tmpdir);
 

tests/seclabeltest.c

@@ -20,14 +20,14 @@ mymain(void)
     model = virSecurityManagerGetModel(mgr);
     if (!model) {
         fprintf(stderr, "Failed to copy secModel model: %s",
-                strerror(errno));
+                g_strerror(errno));
         return EXIT_FAILURE;
     }
 
     doi = virSecurityManagerGetDOI(mgr);
     if (!doi) {
         fprintf(stderr, "Failed to copy secModel DOI: %s",
-                strerror(errno));
+                g_strerror(errno));
         return EXIT_FAILURE;
     }
 

tests/testutils.c

@@ -172,12 +172,12 @@ virTestLoadFile(const char *file, char **buf)
     int len, tmplen, buflen;
 
     if (!fp) {
-        fprintf(stderr, "%s: failed to open: %s\n", file, strerror(errno));
+        fprintf(stderr, "%s: failed to open: %s\n", file, g_strerror(errno));
         return -1;
     }
 
     if (fstat(fileno(fp), &st) < 0) {
-        fprintf(stderr, "%s: failed to fstat: %s\n", file, strerror(errno));
+        fprintf(stderr, "%s: failed to fstat: %s\n", file, g_strerror(errno));
         VIR_FORCE_FCLOSE(fp);
         return -1;
     }
@@ -208,7 +208,7 @@ virTestLoadFile(const char *file, char **buf)
             tmplen -= len;
         }
         if (ferror(fp)) {
-            fprintf(stderr, "%s: read failed: %s\n", file, strerror(errno));
+            fprintf(stderr, "%s: read failed: %s\n", file, g_strerror(errno));
             VIR_FORCE_FCLOSE(fp);
             VIR_FREE(*buf);
             return -1;

tests/virhostcputest.c

@@ -37,7 +37,7 @@ linuxTestCompareFiles(const char *cpuinfofile,
     cpuinfo = fopen(cpuinfofile, "r");
     if (!cpuinfo) {
         fprintf(stderr, "unable to open: %s : %s\n",
-                cpuinfofile, strerror(errno));
+                cpuinfofile, g_strerror(errno));
         goto fail;
     }
 
@@ -86,7 +86,7 @@ linuxCPUStatsToBuf(virBufferPtr buf,
 
     if ((sc_clk_tck = sysconf(_SC_CLK_TCK)) < 0) {
         fprintf(stderr, "sysconf(_SC_CLK_TCK) fails : %s\n",
-                strerror(errno));
+                g_strerror(errno));
         return -1;
     }
     tick_to_nsec = (1000ull * 1000ull * 1000ull) / sc_clk_tck;

tests/virtestmock.c

@@ -76,12 +76,12 @@ printFile(const char *file,
     }
 
     if (!(fp = real_fopen(output, "a"))) {
-        fprintf(stderr, "Unable to open %s: %s\n", output, strerror(errno));
+        fprintf(stderr, "Unable to open %s: %s\n", output, g_strerror(errno));
         abort();
     }
 
     if (flock(fileno(fp), LOCK_EX) < 0) {
-        fprintf(stderr, "Unable to lock %s: %s\n", output, strerror(errno));
+        fprintf(stderr, "Unable to lock %s: %s\n", output, g_strerror(errno));
         fclose(fp);
         abort();
     }