尽管这里有关于此问题的几个答案:我仍然无法使它们适合以下代码,因为它在processFile的segfault
上为4th iteration
:
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <stdbool.h>
#include <malloc.h>
#include <errno.h>
#include <string.h>
struct _version {
int major;
int minor;
}version;
char *inputName;
char *outputName;
char **outputBuffer;
int length;
void init() {
inputName=outputName=0;
outputBuffer = NULL;
length = 0;
version.major = 0;
version.minor = 1;
}
void usage(const char *s) {
printf("Usage: %s -i <input file> -o <output file>\n",s);
printf("\t %s -h:\t prints this help\n",s);
printf("\t %s -v:\t prints version\n",s);
}
bool parseArgs(int argc, char * const argv[]) {
char ch;
char i=0;
if(argc < 2) {
usage(argv[0]);
return false;
}
while ( (ch = getopt(argc,argv,"hvi:o:")) != -1) {
switch(ch) {
case 'v':
printf("Version %d.%d\n", version.major,version.minor);
return false;
break;
case 'i':
inputName = malloc(strlen(optarg)+1);
if(errno == ENOMEM) {
exit(ENOMEM);
}
strcpy(inputName,optarg);
i++;
break;
case 'o':
outputName = malloc(strlen(optarg)+1);
if(errno == ENOMEM) {
exit(ENOMEM);
}
strcpy(outputName,optarg);
i++;
break;
case 'h':
default:
usage(argv[0]);
return false;
break;
}
}
return(i==2);
}
bool processFile() {
printf("trying input:%s\toutput:%s\n",inputName,outputName);
FILE *inf = fopen(inputName,"r");
if(!inf) {int e=errno;perror(inputName); exit(e);}
char line[1024];
while(fgets(line,1024,inf)){
if(strnlen(line,1024)==1024) exit(255);
printf("next line read(line length is %d):%s\n", strnlen(line,1024), line);
outputBuffer = realloc(outputBuffer,(++length)*sizeof(char *));
printf("reallocation bytes requested:%d outputBuffer=0x%0X\n",length*sizeof(char *),outputBuffer);
outputBuffer[length-1] = malloc(strnlen(line,1024)*sizeof(char)+1);
strncpy(outputBuffer[length-1],line,1024);
printf("---------------------------------------------\n");
int i;
}
if(!feof(inf)){
printf("failed reading %s:%d error:%d", inputName, length,ferror(inf));
exit(ferror(inf));
}
if(inf) fclose(inf);
return false;
}
bool writeOutput() {
FILE *outf = fopen(outputName,"w");
if(!outf) {int e=errno;perror(outputName); exit(e);}
if(outf) fclose(outf);
return false;
}
void finish() {
if(inputName) free(inputName);
if(outputName) free(outputName);
}
int main(int argc, char * const argv[]){
init();
bool ok = parseArgs(argc, argv);
if(ok) {
ok = processFile();
if(ok) {
if(writeOutput()) {
printf("Success.\n");
}
}
else {
printf("error processing file\n");
}
}
finish();
}
任何帮助将不胜感激!
阅读注释后,添加代码示例和valgrind输出:
下一行读取(行长为32):libqosadaptor libqosadaptor。%::
请求的重新分配字节数:8 outputBuffer = 0x4C4F360
== 8347 ==大小为1的无效写入
== 8347 == at 0x4A095CC:strncpy(在/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so中)
== 8347 ==通过0x400DFC:processFile(makefileUpgrade.c:83)
== 8347 ==通过0x400F76:main(makefileUpgrade.c:113)
== 8347 ==在分配了大小为33的块后,地址0x4c4f3d1为0字节
== 8347 ==在0x4A0645D:malloc(在/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
== 8347 ==通过0x400DC4:processFile(makefileUpgrade.c:82)
== 8347 ==通过0x400F76:main(makefileUpgrade.c:113)
---------------------------------------------下一行读取(第长度为87):$(SHOW)$(MAKE)$(MAKEOPTS)REL_DIR =适配器/ qos -C
$(ROOT)/适配器/ qos $ * -f makefile
valgrind:m_mallocfree.c:277(mk_plain_bszB):断言'bszB!= 0'
失败了valgrind:这可能是由于您的程序错误导致的
写越过堆块的末尾并破坏堆元数据。如果
您修复了Memcheck报告的所有无效写入,此断言
失败可能会消失。请在举报之前尝试一下
作为一个错误。
== 8347 ==在0x3805028C:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
== 8347 ==通过0x380503E6:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
== 8347 ==通过0x3805AA4A:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
== 8347 ==通过0x3805C9B7:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
== 8347 ==通过0x38021865:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
== 8347 ==通过0x3809C5C2:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
== 8347 ==通过0x380AB21C:??? (在/ usr / lib64 / valgrind / memcheck-amd64-linux中)
预定状态:running_tid = 1
线程1:状态= VgTs_Runnable
== 8347 ==在0x4A083AA:重新分配(在/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so中)
== 8347 ==通过0x400D54:processFile(makefileUpgrade.c:80)
== 8347 ==通过0x400F76:main(makefileUpgrade.c:113)
最佳答案
解决方法很简单,但是很棘手(我的错是直到最后都没有阅读手册页):
strncpy存在错误,因为它始终写入n个字节。
strncpy(outputBuffer[length-1],line,1024);
源字符串要大一些,然后再分配大小,而violla是经典的溢出。
char * strncpy(char * dest,const char * src,size_t n);
如果src的长度小于n,则strncpy()写入其他null
要确保写入的字节总数为n个字节。
关于c - 在第4次迭代的C崩溃中重新分配字符串表,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/25698760/