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crtools: R/W API rewrite

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Kill all the macros for reading/writing image parts. New API looks like

* write_img_buf/write_img
  Write an object into an image. Reports 0 for OK, -1 for error. The _buf
  version accepts object size as an argument, the other one uses sizeof()

* read_img_buf/read_img
  Reads an object from image. Reports 0 for OK, -1 for error or EOF.

* read_img_buf_eof/read_img
  Reads an object from image. Reports 1 for OK, 0 for EOF and -1 for error.
  This is not symmetrical with the previous one, but it was done deliberately
  to make it possible to write code like

  ret = read_img_bug_eof();
  if (ret <= 0)
	return ret; /* 0 means OK, all is done, -1 means error was met */.

  ... /* 1 means object was read, can proceed */

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This commit is contained in:
Pavel Emelyanov
2012-01-22 20:20:40 +04:00
committed by Cyrill Gorcunov
parent dbf3c1a8cd
commit 164ccc095f
9 changed files with 167 additions and 127 deletions
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88
include/util.h
View File

@@ -8,6 +8,7 @@
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <dirent.h>
@@ -116,40 +117,73 @@ extern void printk(const char *format, ...);
#define BUG_ON(condition) BUG_ON_HANDLER((condition))
#define write_ptr(fd, ptr) \
write(fd, (ptr), sizeof(*(ptr)))
/*
* Write buffer @ptr of @size bytes into @fd file
* Returns
* 0 on success
* -1 on error (error message is printed)
*/
static inline int write_img_buf(int fd, void *ptr, int size)
{
int ret;
ret = write(fd, ptr, size);
if (ret == size)
return 0;
#define write_ptr_safe(fd, ptr, err) \
jerr(write_ptr(fd, ptr) != sizeof(*(ptr)), err)
if (ret < 0)
pr_perror("Can't write img file\n");
else
pr_err("Img trimmed %d/%d\n", ret, size);
return -1;
}
#define write_safe(fd, ptr, size, err) \
jerr(write(fd, (ptr), (size)) != (size), err)
#define write_img(fd, ptr) write_img_buf((fd), (ptr), sizeof(*(ptr)))
#define write_safe_imm(fd, imm, err) \
do { \
typeof(imm) x__ = imm; \
write_ptr_safe(fd, &x__, err); \
} while (0)
/*
* Read buffer @ptr of @size bytes from @fd file
* Returns
* 1 on success
* 0 on EOF (silently)
* -1 on error (error message is printed)
*/
static inline int read_img_buf_eof(int fd, void *ptr, int size)
{
int ret;
ret = read(fd, ptr, size);
if (ret == size)
return 1;
if (ret == 0)
return 0;
#define read_safe(fd, ptr, size, err) \
jerr(read(fd, ptr, (size)) != (size), err)
if (ret < 0)
pr_perror("Can't read img file\n");
else
pr_err("Img trimmed %d/%d\n", ret, size);
return -1;
}
#define read_ptr_safe(fd, ptr, err) \
jerr(read(fd, ptr, sizeof(*(ptr))) != sizeof(*(ptr)), err)
#define read_img_eof(fd, ptr) read_img_buf_eof((fd), (ptr), sizeof(*(ptr)))
#define read_safe_eof(fd, ptr, size, err) \
({ \
size_t rc__ = read(fd, ptr, (size)); \
if (rc__ && rc__ != (size)) { \
pr_err("img corruption %d/%d\n", \
rc__, (size)); \
goto err; \
} \
rc__; \
})
/*
* Read buffer @ptr of @size bytes from @fd file
* Returns
* 1 on success
* -1 on error or EOF (error message is printed)
*/
static inline int read_img_buf(int fd, void *ptr, int size)
{
int ret;
#define read_ptr_safe_eof(fd, ptr, err) \
read_safe_eof(fd, ptr, sizeof(*(ptr)), err)
ret = read_img_buf_eof(fd, ptr, size);
if (ret == 0) {
pr_err("Unexpected EOF\n");
ret = -1;
}
return ret;
}
#define read_img(fd, ptr) read_img_buf((fd), (ptr), sizeof(*(ptr)))
#define memzero_p(p) memset(p, 0, sizeof(*p))
#define memzero(p, size) memset(p, 0, size)