HTTP(socket)下载遇到valgrind提示的错误： Conditional jump or move depends on uninitialised value(s)

来源：互联网发布：网络七层协议详解编辑：程序博客网时间：2024/06/06 00:23

我写了个http下载函数，下载txt、jpg都正常，就是下载php有问题：valgrind会报错Conditional jump or move depends on uninitialised value(s)，

函数定义：
char* httpdown(char *domain, int port, char *uri, int *length) ；

调用：
strcpy(uri, "/net.php");
rtn = httpdown("192.168.1.24", 80, uri, &len);
printf("File saved\n%s\n", rtn);

大概发现printf这句会报那个错，如果uri是个txt或者jpg都不会报。

经过一番折腾后发现是memcpy的问题，改成strncpy就可以了，但那样如果是图片又不能正确处理，所以，就只好判断下返回数据类型了，具体代码：

char* httpdown(char *domain, int port, char *uri, int *length) {char buffer[RECEIVE_BUF + 1];//memset(buffer, '\0', RECEIVE_BUF + 1);char* rtn;rtn = malloc(DOWNLOAD_BUF);rtn[0] = 0;(*length) = 0;int sockfd = openRequest(domain, port, uri, rtn, buffer);#ifdef DEBUGif (sockfd < 0){printf("Connect to %s:%d failed\n", domain, port);return rtn;}#elseif (sockfd < 0)return rtn;#endif#ifdef DEBUGprintf("Init connect to %s:%d done, fd=%d\n", domain, port, sockfd);#endifint len, needLen, dataLen=0;int current_buffer_size = DOWNLOAD_BUF;rtn[0] = 0;buffer[0] = 0;int type = -1;char * tmp;while (1) {len = recv(sockfd, buffer, RECEIVE_BUF, 0);if(type<0){//如果没有取得返回数据类型tmp = strstr(buffer, "Content-Type");//如果已经获得content-type——潜在bug如果content-type和他的值没有一起返回则会出问题，不管了if(tmp!=NULL){tmp = strstr(tmp, "text");if(tmp==NULL)type=1;elsetype=0;}}if (len > 0) {needLen = dataLen + len;while (current_buffer_size <= needLen) {current_buffer_size += DOWNLOAD_BUF;#ifdef DEBUGprintf("realloc to %d\n", current_buffer_size);#endifrtn = realloc(rtn, current_buffer_size);rtn[dataLen] = 0;}#ifdef DEBUGprintf("http sockect received %d data\n", len);#endifif(type<1)//字符串用strncatstrncat(rtn+dataLen, buffer, len);elsememcpy(rtn+dataLen, buffer, len);dataLen+=len;} else {if (len < 0) {if(errno>0)sprintf(rtn, "消息接收失败！错误代码是%d，错误信息是'%s'\n", errno,strerror(errno));return rtn;}#ifdef DEBUGprintf("Read data from %s:%d, complete\n", domain, port);#endifbreak;}}close(sockfd);(*length) = dataLen;return rtn;}

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