【发布时间】：2011-07-02 11:10:43
【问题描述】：
我有一个调用getline() 的函数，它从标准文本文件中读取行。这些行以\r\n 结尾，因为这是规范所要求的，因为它是 VCARD 文件的“互联网标准”。
无论如何，我在 OpenSUSE 11.3 上使用最新的 GCC 和 Valgrind 版本通过 Valgrind 运行这个婴儿；没有错误。但是，由于与此问题无关的原因，我将发行版切换到 Back Track 4（基于 Ubuntu），现在我收到大量 Valgrind 错误：
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x40164A1: (within /lib/ld-2.11.1.so)
==21536== by 0x4007C04: (within /lib/ld-2.11.1.so)
==21536== by 0x4002A2C: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x40164AC: (within /lib/ld-2.11.1.so)
==21536== by 0x4007C04: (within /lib/ld-2.11.1.so)
==21536== by 0x4002A2C: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
--21536-- Warning: DWARF2 CFI reader: unhandled DW_OP_ opcode 0x55
--21536-- Warning: DWARF2 CFI reader: unhandled DW_OP_ opcode 0x55
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
--21536-- DWARF2 CFI reader: unhandled CFI instruction 0:10
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x400B217: (within /lib/ld-2.11.1.so)
==21536== by 0x40031D0: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x400AF0F: (within /lib/ld-2.11.1.so)
==21536== by 0x40031D0: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x400B27A: (within /lib/ld-2.11.1.so)
==21536== by 0x40031D0: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x400A5DE: (within /lib/ld-2.11.1.so)
==21536== by 0x40030FE: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x400A5E6: (within /lib/ld-2.11.1.so)
==21536== by 0x40030FE: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x400AF0F: (within /lib/ld-2.11.1.so)
==21536== by 0x40030FE: (within /lib/ld-2.11.1.so)
==21536== by 0x4014206: (within /lib/ld-2.11.1.so)
==21536== by 0x4000C6C: (within /lib/ld-2.11.1.so)
==21536== by 0x4000856: (within /lib/ld-2.11.1.so)
==21536==
==21536== Invalid read of size 8
==21536== at 0x40B4785: (within /lib/tls/i686/cmov/libc-2.11.1.so)
==21536== by 0x8049EFB: main (vcutil.c:496)
==21536== Address 0x419d1b0 is 8 bytes before a block of size 120 alloc'd
==21536== at 0x4025D2E: malloc (vg_replace_malloc.c:207)
==21536== by 0x409DF9D: getdelim (in /lib/tls/i686/cmov/libc-2.11.1.so)
==21536== by 0x408F3A2: getline (in /lib/tls/i686/cmov/libc-2.11.1.so)
==21536== by 0x804947C: getUnfolded (vcutil.c:299)
==21536== by 0x8049EFB: main (vcutil.c:496)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x40B47AD: (within /lib/tls/i686/cmov/libc-2.11.1.so)
==21536== by 0x8049EFB: main (vcutil.c:496)
==21536==
==21536== Conditional jump or move depends on uninitialised value(s)
==21536== at 0x8049524: getUnfolded (vcutil.c:307)
==21536== by 0x8049EFB: main (vcutil.c:496)
我特别不知道这些行指的是什么
--21536-- Warning: DWARF2 CFI reader: unhandled DW_OP_ opcode 0x55
意思。这些是我更换发行版后的新功能。
无论如何，作为参考，这是我的问题：
VcStatus getUnfolded (FILE *const vcf, char **const buff) {
//int const buffSize = 30;
size_t lineSize = 0;
int done = 0; //Set to one if the next line checked does not entail unfolding
static char* queue = NULL; //A queue to store the next line read in
static int lineNum = 0;
char* buffer = NULL; //The dynamic memory that will be linked to buf
int valid_line = 0; //Set to one if the line contains characters other then whitespace
char* temp; //Used to point to the location of \r\n in the buffer
VcStatus error; //Initialize VcStatus with appropriate values
error.code = OK;
error.linefrom = lineNum;
error.lineto = 0;
//Special case for resetting getUnfolded()
if (vcf == NULL){
lineNum = 0;
if (queue != NULL) queue = NULL;
error.linefrom = 0;
error.lineto = 0;
return error;
}
//Copies any string contained in queue from last time into buffer
if (queue != NULL) {
buffer = malloc (strlen (queue)+1);
strcpy (buffer, queue);
strcpy (queue, "");
}
//If the end of file has been reached, last line is returned.
if (feof (vcf) != 0) {
queue = NULL;
lineNum += 1;
if (buffer != NULL) {
if (strcmp (buffer, "") != 0)*buff = buffer;
}
else *buff = NULL;
return error;
}
while (done == 0) {
//Gets a new line from the vcf file, and returns null if there is no more data to be returned
getline (&queue, &lineSize, vcf);
if (ferror(vcf) != 0) {
error.code = IOERR;
return error;
}
//Sets valid_line to 1 if the line read in contains any characters other then whitespace
for (int i = 0; i < strlen (queue); i++){
if (queue[i] != '\r' && queue[i] != '\n' && queue[i] != ' ' && queue[i] != '\t') valid_line = 1;
}
if (feof (vcf) && valid_line == 0) {
queue = NULL;
break;
}
if (valid_line == 1){
//Finds the 'internet standard' newline and replaces it with a null terminator
temp = strstr (queue, "\r\n");
if (temp != NULL) strcpy (temp, "\0");
//Sets the buffer equal to contents of queue and resets queue if buffer is empty
if (buffer == NULL) {
buffer = malloc (strlen (queue)+1);
lineNum = lineNum + 1;
strcpy (buffer, queue);
strcpy (queue, "");
//Checks for leading whitespace to indicate a folded line, and unfolds
}else if (queue [0] == ' ' || queue [0] == '\t') {
lineNum = lineNum + 1;
buffer = realloc (buffer, strlen (buffer)+strlen (queue)+2);
strcat (buffer, queue+1);
strcpy (queue, "");
//If both conditions above are false, buffer contains the next valid line
}else{
error.lineto = lineNum;
lineNum += 1;
done = 1;
}
}
}
*buff = buffer;
return error;
}
...以及向其发送测试数据的虚拟函数：
int main () {
FILE* fp = fopen ("test.vcf", "r");
char * buff;
getUnfolded (fp, &buff);
}
test.vcf 文件实际上只是一个简单的文本文件
任何帮助都会很棒。
【问题讨论】：
-
关于谷歌的事情很有趣：P 向你表明，如果这是第一个结果，我没有运气谷歌搜索这个问题。是的，我在这台新主机上重新编译了多次，源代码没有改变……test.vcf 文件使用了正确的 EOL CRLF……这是一个相当令人头疼的问题！
-
如果我没记错的话，'dwarf2 opcode' 错误可能只是您使用的 valgrind 版本比您使用的编译器旧，可以放心地忽略。关于您的错误：您致电
strlen(queue)。如果该行比lineSize长，会发生什么？如果你得出代码没问题的结论，你可以生成一个抑制文件继续你的生活。 -
感谢您的回复，很高兴理解为什么 valgrind 会向我吐出毫无意义的废话！如果您知道如何抑制这些错误，我将有兴趣学习如何抑制这些错误？而且我不知道如何解决您所指的错误。据我了解，如果队列从上次调用函数时开始包含某些内容，则调用该 strlen(queue) 行。我不断收到诸如“比较中使用未初始化的变量”之类的错误，因为我的变量已在条件语句中初始化（在每种情况下），我也不知道如何摆脱这些。
-
哦，那个 lineSize 变量是没有意义的；我将把 0 硬编码到 getline 中。 Getline 无论如何都会“自动”调整缓冲区的大小，所以我什至看不到“建议的缓冲区大小”的意义：S
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@Borealid - 你先生是我的英雄。我下载了最新版本的 valgrind 并对其进行了编译，现在我的错误为零。谢谢，女士们，先生们，案件已结案。胖女人唱了：D