1*a3a45f30SXin Li // Copyright 2015 The Chromium OS Authors. All rights reserved.
2*a3a45f30SXin Li // Use of this source code is governed by a BSD-style license that can be
3*a3a45f30SXin Li // found in the LICENSE file.
4*a3a45f30SXin Li
5*a3a45f30SXin Li #include "bsdiff/file.h"
6*a3a45f30SXin Li
7*a3a45f30SXin Li #include <errno.h>
8*a3a45f30SXin Li #include <fcntl.h>
9*a3a45f30SXin Li #ifdef __linux__
10*a3a45f30SXin Li #include <linux/fs.h>
11*a3a45f30SXin Li #endif // __linux__
12*a3a45f30SXin Li #include <string.h>
13*a3a45f30SXin Li #include <sys/ioctl.h>
14*a3a45f30SXin Li #include <sys/stat.h>
15*a3a45f30SXin Li #include <sys/types.h>
16*a3a45f30SXin Li #include <unistd.h>
17*a3a45f30SXin Li
18*a3a45f30SXin Li // TEMP_FAILURE_RETRY is defined by some versions of <unistd.h>.
19*a3a45f30SXin Li #ifndef TEMP_FAILURE_RETRY
20*a3a45f30SXin Li #include <utils/Compat.h>
21*a3a45f30SXin Li #endif
22*a3a45f30SXin Li
23*a3a45f30SXin Li #include <algorithm>
24*a3a45f30SXin Li
25*a3a45f30SXin Li namespace bsdiff {
26*a3a45f30SXin Li
FOpen(const char * pathname,int flags)27*a3a45f30SXin Li std::unique_ptr<File> File::FOpen(const char* pathname, int flags) {
28*a3a45f30SXin Li int fd = TEMP_FAILURE_RETRY(open(pathname, flags, 0644));
29*a3a45f30SXin Li if (fd < 0)
30*a3a45f30SXin Li return std::unique_ptr<File>();
31*a3a45f30SXin Li return std::unique_ptr<File>(new File(fd));
32*a3a45f30SXin Li }
33*a3a45f30SXin Li
~File()34*a3a45f30SXin Li File::~File() {
35*a3a45f30SXin Li Close();
36*a3a45f30SXin Li }
37*a3a45f30SXin Li
Read(void * buf,size_t count,size_t * bytes_read)38*a3a45f30SXin Li bool File::Read(void* buf, size_t count, size_t* bytes_read) {
39*a3a45f30SXin Li if (fd_ < 0) {
40*a3a45f30SXin Li errno = EBADF;
41*a3a45f30SXin Li return false;
42*a3a45f30SXin Li }
43*a3a45f30SXin Li ssize_t rc = TEMP_FAILURE_RETRY(read(fd_, buf, count));
44*a3a45f30SXin Li if (rc == -1)
45*a3a45f30SXin Li return false;
46*a3a45f30SXin Li *bytes_read = static_cast<size_t>(rc);
47*a3a45f30SXin Li return true;
48*a3a45f30SXin Li }
49*a3a45f30SXin Li
Write(const void * buf,size_t count,size_t * bytes_written)50*a3a45f30SXin Li bool File::Write(const void* buf, size_t count, size_t* bytes_written) {
51*a3a45f30SXin Li if (fd_ < 0) {
52*a3a45f30SXin Li errno = EBADF;
53*a3a45f30SXin Li return false;
54*a3a45f30SXin Li }
55*a3a45f30SXin Li ssize_t rc = TEMP_FAILURE_RETRY(write(fd_, buf, count));
56*a3a45f30SXin Li if (rc == -1)
57*a3a45f30SXin Li return false;
58*a3a45f30SXin Li *bytes_written = static_cast<size_t>(rc);
59*a3a45f30SXin Li return true;
60*a3a45f30SXin Li }
61*a3a45f30SXin Li
Seek(off_t pos)62*a3a45f30SXin Li bool File::Seek(off_t pos) {
63*a3a45f30SXin Li if (fd_ < 0) {
64*a3a45f30SXin Li errno = EBADF;
65*a3a45f30SXin Li return false;
66*a3a45f30SXin Li }
67*a3a45f30SXin Li
68*a3a45f30SXin Li off_t newpos = lseek(fd_, pos, SEEK_SET);
69*a3a45f30SXin Li if (newpos < 0)
70*a3a45f30SXin Li return false;
71*a3a45f30SXin Li if (newpos != pos) {
72*a3a45f30SXin Li errno = EINVAL;
73*a3a45f30SXin Li return false;
74*a3a45f30SXin Li }
75*a3a45f30SXin Li return true;
76*a3a45f30SXin Li }
77*a3a45f30SXin Li
Close()78*a3a45f30SXin Li bool File::Close() {
79*a3a45f30SXin Li if (fd_ < 0) {
80*a3a45f30SXin Li errno = EBADF;
81*a3a45f30SXin Li return false;
82*a3a45f30SXin Li }
83*a3a45f30SXin Li bool success = close(fd_) == 0;
84*a3a45f30SXin Li if (!success && errno == EINTR)
85*a3a45f30SXin Li success = true;
86*a3a45f30SXin Li fd_ = -1;
87*a3a45f30SXin Li return success;
88*a3a45f30SXin Li }
89*a3a45f30SXin Li
GetSize(uint64_t * size)90*a3a45f30SXin Li bool File::GetSize(uint64_t* size) {
91*a3a45f30SXin Li struct stat stbuf;
92*a3a45f30SXin Li if (fstat(fd_, &stbuf) == -1)
93*a3a45f30SXin Li return false;
94*a3a45f30SXin Li if (S_ISREG(stbuf.st_mode)) {
95*a3a45f30SXin Li *size = stbuf.st_size;
96*a3a45f30SXin Li return true;
97*a3a45f30SXin Li }
98*a3a45f30SXin Li if (S_ISBLK(stbuf.st_mode)) {
99*a3a45f30SXin Li #if defined(BLKGETSIZE64)
100*a3a45f30SXin Li return ioctl(fd_, BLKGETSIZE64, size);
101*a3a45f30SXin Li #elif defined(DKIOCGETBLOCKCOUNT)
102*a3a45f30SXin Li uint64_t sectors = 0;
103*a3a45f30SXin Li if (ioctl(fd_, DKIOCGETBLOCKCOUNT, §ors) == 0) {
104*a3a45f30SXin Li *size = sectors << 9;
105*a3a45f30SXin Li return true;
106*a3a45f30SXin Li }
107*a3a45f30SXin Li return false;
108*a3a45f30SXin Li #else
109*a3a45f30SXin Li // Fall back to doing seeks to know the EOF.
110*a3a45f30SXin Li off_t pos = lseek(fd_, 0, SEEK_CUR);
111*a3a45f30SXin Li if (pos == -1)
112*a3a45f30SXin Li return false;
113*a3a45f30SXin Li off_t end_pos = lseek(fd_, 0, SEEK_END);
114*a3a45f30SXin Li if (end_pos == -1)
115*a3a45f30SXin Li return false;
116*a3a45f30SXin Li *size = end_pos;
117*a3a45f30SXin Li lseek(fd_, 0, SEEK_END);
118*a3a45f30SXin Li return true;
119*a3a45f30SXin Li #endif
120*a3a45f30SXin Li }
121*a3a45f30SXin Li return false;
122*a3a45f30SXin Li }
123*a3a45f30SXin Li
File(int fd)124*a3a45f30SXin Li File::File(int fd)
125*a3a45f30SXin Li : fd_(fd) {}
126*a3a45f30SXin Li
127*a3a45f30SXin Li } // namespace bsdiff
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