Linux内核中如何将char[]字符串转换为int？
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How convert a char[] string to int in the Linux kernel?
提问by caeycae
How convert char[] to int in linux kernel
如何在linux内核中将char[]转换为int
with validation that the text entered is actually an int?
验证输入的文本实际上是一个整数？
int procfile_write(struct file *file, const char *buffer, unsigned long count,
void *data)
{
char procfs_buffer[PROCFS_MAX_SIZE];
/* get buffer size */
unsigned long procfs_buffer_size = count;
if (procfs_buffer_size > PROCFS_MAX_SIZE ) {
procfs_buffer_size = PROCFS_MAX_SIZE;
}
/* write data to the buffer */
if ( copy_from_user(procfs_buffer, buffer, procfs_buffer_size) ) {
return -EFAULT;
}
int = buffer2int(procfs_buffer, procfs_buffer_size);
return procfs_buffer_size;
}
采纳答案by FrankH.
See the various incarnations of kstrtol()in #include <include/linux/kernel.h>in your friendly linux source tree.
在友好的 linux 源代码树中查看kstrtol()in的各种化身#include <include/linux/kernel.h>。
Which one you need depends on whether the *bufferis a user or a kernel address, and on how strict your needs on error handling / checking of the buffer contents are (things like, is 123qxinvalid or should it return 123?).
您需要哪一个取决于*buffer是用户地址还是内核地址，以及您对错误处理/检查缓冲区内容的需求有多严格（例如，123qx无效还是应该返回123？）。
回答by Blazes
Use atoi and isdigit (note isdigit just takes a char). http://www.cplusplus.com/reference/clibrary/cctype/isdigit/
使用 atoi 和 isdigit （注意 isdigit 只需要一个字符）。 http://www.cplusplus.com/reference/clibrary/cctype/isdigit/
回答by Bhargav Bhat
You could use strtoulor strtol. Here's a link to the man pages:
您可以使用strtoul或strtol。这是手册页的链接：
http://www.kernel.org/doc/man-pages/online/pages/man3/strtoul.3.html
http://www.kernel.org/doc/man-pages/online/pages/man3/strtol.3.html
http://www.kernel.org/doc/man-pages/online/pages/man3/strtoul.3.html
http://www.kernel.org/doc/man-pages/online/pages/man3/strtol .3.html
回答by Vikram.exe
Because of the unavailability of a lot of common function/macros in linux kernel, you can not use any direct function to get integer value from a string buffer.
由于 linux 内核中许多常用函数/宏不可用，因此您不能使用任何直接函数从字符串缓冲区中获取整数值。
This is the code that I have been using for a long time for doing this and it can be used on all *NIX flavors (probably without any modification).
这是我长期以来一直使用的代码，它可以用于所有 *NIX 风格（可能无需任何修改）。
This is the modified form of code, which I used a long time back from an open source project (don't remember the name now).
这是修改后的代码形式，我从一个开源项目中使用了很长时间（现在不记得名字了）。
#define ISSPACE(c) ((c) == ' ' || ((c) >= '\t' && (c) <= '\r'))
#define ISASCII(c) (((c) & ~0x7f) == 0)
#define ISUPPER(c) ((c) >= 'A' && (c) <= 'Z')
#define ISLOWER(c) ((c) >= 'a' && (c) <= 'z')
#define ISALPHA(c) (ISUPPER(c) || ISLOWER(c))
#define ISDIGIT(c) ((c) >= '0' && (c) <= '9')
unsigned long mystr_toul (
char* nstr,
char** endptr,
int base)
{
#if !(defined(__KERNEL__))
return strtoul (nstr, endptr, base); /* user mode */
#else
char* s = nstr;
unsigned long acc;
unsigned char c;
unsigned long cutoff;
int neg = 0, any, cutlim;
do
{
c = *s++;
} while (ISSPACE(c));
if (c == '-')
{
neg = 1;
c = *s++;
}
else if (c == '+')
c = *s++;
if ((base == 0 || base == 16) &&
c == '0' && (*s == 'x' || *s == 'X'))
{
c = s[1];
s += 2;
base = 16;
}
if (base == 0)
base = c == '0' ? 8 : 10;
cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
for (acc = 0, any = 0; ; c = *s++)
{
if (!ISASCII(c))
break;
if (ISDIGIT(c))
c -= '0';
else if (ISALPHA(c))
c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
else
break;
if (c >= base)
break;
if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
any = -1;
else
{
any = 1;
acc *= base;
acc += c;
}
}
if (any < 0)
{
acc = INT_MAX;
}
else if (neg)
acc = -acc;
if (endptr != 0)
*((const char **)endptr) = any ? s - 1 : nstr;
return (acc);
#endif
}
回答by Sonny
I use sscanf() (the kernel version) to scan from a string stream, and it works on 2.6.39-gentoo-r3. Frankly, I could never get simple_strtol() to work in the kernel--I am currently figuring out why this doesn't work on my box.
我使用 sscanf()（内核版本）从字符串流中扫描，它适用于 2.6.39-gentoo-r3。坦率地说，我永远无法让 simple_strtol() 在内核中工作——我目前正在弄清楚为什么这在我的盒子上不起作用。
...
memcpy(bufActual, calc_buffer, calc_buffer_size);
/* a = simple_strtol(bufActual, NULL, 10); */ // Could not get this to work
sscanf(bufActual, "%c%ld", &opr, &a); // places '+' in opr and a=20 for bufActual = "20+##代码##"
...
