openvz: use virAsprintf to avoid large stacks

* src/openvz/openvz_conf.c (openvzLocateConfFile): Alter
signature.
(openvzGetVPSUUID, openvzSetDefinedUUID)
(openvzWriteVPSConfigParam, openvzReadVPSConfigParam)
(openvzCopyDefaultConfig): Adjust callers.

src/openvz/openvz_conf.c

@@ -55,7 +55,7 @@
 
 static char *openvzLocateConfDir(void);
 static int openvzGetVPSUUID(int vpsid, char *uuidstr, size_t len);
-static int openvzLocateConfFile(int vpsid, char *conffile, int maxlen, const char *ext);
+static int openvzLocateConfFile(int vpsid, char **conffile, const char *ext);
 static int openvzAssignUUIDs(void);
 
 int
@@ -615,12 +615,15 @@ error:
 int
 openvzWriteVPSConfigParam(int vpsid, const char *param, const char *value)
 {
-    char conf_file[PATH_MAX];
+    char *conf_file;
+    int ret;
 
-    if (openvzLocateConfFile(vpsid, conf_file, PATH_MAX, "conf")<0)
+    if (openvzLocateConfFile(vpsid, &conf_file, "conf") < 0)
         return -1;
 
-    return openvzWriteConfigParam(conf_file, param, value);
+    ret = openvzWriteConfigParam(conf_file, param, value);
+    VIR_FREE(conf_file);
+    return ret;
 }
 
 static int
@@ -676,12 +679,15 @@ openvzReadConfigParam(const char * conf_file ,const char * param, char *value, i
 int
 openvzReadVPSConfigParam(int vpsid ,const char * param, char *value, int maxlen)
 {
-    char conf_file[PATH_MAX];
+    char *conf_file;
+    int ret;
 
-    if (openvzLocateConfFile(vpsid, conf_file, PATH_MAX, "conf")<0)
+    if (openvzLocateConfFile(vpsid, &conf_file, "conf") < 0)
         return -1;
 
-    return openvzReadConfigParam(conf_file, param, value, maxlen);
+    ret = openvzReadConfigParam(conf_file, param, value, maxlen);
+    VIR_FREE(conf_file);
+    return ret;
 }
 
 static int
@@ -736,7 +742,7 @@ openvzCopyDefaultConfig(int vpsid)
     char * confdir = NULL;
     char * default_conf_file = NULL;
     char configfile_value[PATH_MAX];
-    char conf_file[PATH_MAX];
+    char *conf_file = NULL;
     int ret = -1;
 
     if (openvzReadConfigParam(VZ_CONF_FILE, "CONFIGFILE", configfile_value,
@@ -747,12 +753,13 @@ openvzCopyDefaultConfig(int vpsid)
     if (confdir == NULL)
         goto cleanup;
 
-    if (virAsprintf(&default_conf_file, "%s/ve-%s.conf-sample", confdir, configfile_value) < 0) {
+    if (virAsprintf(&default_conf_file, "%s/ve-%s.conf-sample", confdir,
+                    configfile_value) < 0) {
         virReportOOMError();
         goto cleanup;
     }
 
-    if (openvzLocateConfFile(vpsid, conf_file, PATH_MAX, "conf")<0)
+    if (openvzLocateConfFile(vpsid, &conf_file, "conf") < 0)
         goto cleanup;
 
     if (openvz_copyfile(default_conf_file, conf_file)<0)
@@ -762,6 +769,7 @@ openvzCopyDefaultConfig(int vpsid)
 cleanup:
     VIR_FREE(confdir);
     VIR_FREE(default_conf_file);
+    VIR_FREE(conf_file);
     return ret;
 }
 
@@ -770,7 +778,7 @@ cleanup:
 *         0 - OK
 */
 static int
-openvzLocateConfFile(int vpsid, char *conffile, int maxlen, const char *ext)
+openvzLocateConfFile(int vpsid, char **conffile, const char *ext)
 {
     char * confdir;
     int ret = 0;
@@ -779,9 +787,11 @@ openvzLocateConfFile(int vpsid, char *conffile, int maxlen, const char *ext)
     if (confdir == NULL)
         return -1;
 
-    if (snprintf(conffile, maxlen, "%s/%d.%s",
-                 confdir, vpsid, ext ? ext : "conf") >= maxlen)
+    if (virAsprintf(conffile, "%s/%d.%s", confdir, vpsid,
+                    ext ? ext : "conf") < 0) {
+        virReportOOMError();
         ret = -1;
+    }
 
     VIR_FREE(confdir);
     return ret;
@@ -830,27 +840,25 @@ openvz_readline(int fd, char *ptr, int maxlen)
 static int
 openvzGetVPSUUID(int vpsid, char *uuidstr, size_t len)
 {
-    char conf_file[PATH_MAX];
+    char *conf_file;
     char line[1024];
     char *saveptr = NULL;
     char *uuidbuf;
     char *iden;
     int fd, ret;
-    int retval = 0;
+    int retval = -1;
 
-    if (openvzLocateConfFile(vpsid, conf_file, PATH_MAX, "conf")<0)
+    if (openvzLocateConfFile(vpsid, &conf_file, "conf") < 0)
         return -1;
 
     fd = open(conf_file, O_RDONLY);
     if (fd == -1)
-        return -1;
+        goto cleanup;
 
     while (1) {
         ret = openvz_readline(fd, line, sizeof(line));
-        if (ret == -1) {
-            close(fd);
-            return -1;
-        }
+        if (ret == -1)
+            goto cleanup;
 
         if (ret == 0) { /* EoF, UUID was not found */
             uuidstr[0] = 0;
@@ -861,12 +869,19 @@ openvzGetVPSUUID(int vpsid, char *uuidstr, size_t len)
         uuidbuf = strtok_r(NULL, "\n", &saveptr);
 
         if (iden != NULL && uuidbuf != NULL && STREQ(iden, "#UUID:")) {
-            if (virStrcpy(uuidstr, uuidbuf, len) == NULL)
-                retval = -1;
+            if (virStrcpy(uuidstr, uuidbuf, len) == NULL) {
+                openvzError(VIR_ERR_INTERNAL_ERROR,
+                            _("invalid uuid %s"), uuidbuf);
+                goto cleanup;
+            }
             break;
         }
     }
-    close(fd);
+    retval = 0;
+cleanup:
+    if (fd >= 0)
+        close(fd);
+    VIR_FREE(conf_file);
 
     return retval;
 }
@@ -877,22 +892,23 @@ openvzGetVPSUUID(int vpsid, char *uuidstr, size_t len)
 int
 openvzSetDefinedUUID(int vpsid, unsigned char *uuid)
 {
-    char conf_file[PATH_MAX];
+    char *conf_file;
     char uuidstr[VIR_UUID_STRING_BUFLEN];
+    int ret = -1;
 
     if (uuid == NULL)
         return -1;
 
-    if (openvzLocateConfFile(vpsid, conf_file, PATH_MAX, "conf")<0)
+    if (openvzLocateConfFile(vpsid, &conf_file, "conf") < 0)
         return -1;
 
     if (openvzGetVPSUUID(vpsid, uuidstr, sizeof(uuidstr)))
-        return -1;
+        goto cleanup;
 
     if (uuidstr[0] == 0) {
         FILE *fp = fopen(conf_file, "a"); /* append */
         if (fp == NULL)
-            return -1;
+            goto cleanup;
 
         virUUIDFormat(uuid, uuidstr);
 
@@ -900,10 +916,13 @@ openvzSetDefinedUUID(int vpsid, unsigned char *uuid)
            and be careful always to close the stream.  */
         if ((fprintf(fp, "\n#UUID: %s\n", uuidstr) < 0)
             + (fclose(fp) == EOF))
-            return -1;
+            goto cleanup;
     }
 
-    return 0;
+    ret = 0;
+cleanup:
+    VIR_FREE(conf_file);
+    return ret;
 }
 
 static int