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#include "kexec-zlib.h"
#include "kexec.h"
#ifdef HAVE_LIBZ
#define _GNU_SOURCE
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <zlib.h>
static void _gzerror(gzFile fp, int *errnum, const char **errmsg)
{
*errmsg = gzerror(fp, errnum);
if (*errnum == Z_ERRNO) {
*errmsg = strerror(*errnum);
}
}
int is_zlib_file(const char *filename, off_t *r_size)
{
gzFile fp;
int errnum;
int is_zlib_file = 0; /* default: It's not in gzip format */
const char *msg;
ssize_t result;
if (!filename)
goto out;
fp = gzopen(filename, "rb");
if (fp == 0) {
_gzerror(fp, &errnum, &msg);
dbgprintf("Cannot open `%s': %s\n", filename, msg);
goto out;
}
if (!gzdirect(fp))
/* It's in gzip format */
is_zlib_file = 1;
result = gzclose(fp);
if (result != Z_OK) {
_gzerror(fp, &errnum, &msg);
dbgprintf(" Close of %s failed: %s\n", filename, msg);
}
out:
return is_zlib_file;
}
char *zlib_decompress_file(const char *filename, off_t *r_size)
{
gzFile fp;
int errnum;
const char *msg;
char *buf = NULL;
off_t size = 0, allocated;
ssize_t result;
dbgprintf("Try gzip decompression.\n");
*r_size = 0;
if (!filename) {
return NULL;
}
fp = gzopen(filename, "rb");
if (fp == 0) {
_gzerror(fp, &errnum, &msg);
dbgprintf("Cannot open `%s': %s\n", filename, msg);
return NULL;
}
if (gzdirect(fp)) {
/* It's not in gzip format */
goto fail;
}
allocated = 65536;
buf = xmalloc(allocated);
do {
if (size == allocated) {
allocated <<= 1;
buf = xrealloc(buf, allocated);
}
result = gzread(fp, buf + size, allocated - size);
if (result < 0) {
if ((errno == EINTR) || (errno == EAGAIN))
continue;
_gzerror(fp, &errnum, &msg);
dbgprintf("Read on %s of %d bytes failed: %s\n",
filename, (int)(allocated - size), msg);
size = 0;
goto fail;
}
size += result;
} while(result > 0);
fail:
result = gzclose(fp);
if (result != Z_OK) {
_gzerror(fp, &errnum, &msg);
dbgprintf(" Close of %s failed: %s\n", filename, msg);
}
if (size > 0) {
*r_size = size;
} else {
free(buf);
buf = NULL;
}
return buf;
}
#else
int is_zlib_file(const char *filename, off_t *r_size)
{
return 0;
}
char *zlib_decompress_file(const char *UNUSED(filename), off_t *UNUSED(r_size))
{
return NULL;
}
#endif /* HAVE_ZLIB */
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