1 /*
2 * Copyright (c) Christos Zoulas 2017.
3 * All Rights Reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice immediately at the beginning of the file, without modification,
10 * this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
19 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27 #include "file.h"
28
29 #ifndef lint
30 FILE_RCSID("@(#)$File: buffer.c,v 1.13 2023/07/02 12:48:39 christos Exp $")
31 #endif /* lint */
32
33 #include "magic.h"
34 #ifdef HAVE_UNISTD_H
35 #include <unistd.h>
36 #endif
37 #include <string.h>
38 #include <stdlib.h>
39 #include <sys/stat.h>
40
41 void
buffer_init(struct buffer * b,int fd,const zend_stat_t * st,const void * data,size_t len)42 buffer_init(struct buffer *b, int fd, const zend_stat_t *st, const void *data,
43 size_t len)
44 {
45 b->fd = fd;
46 if (st)
47 memcpy(&b->st, st, sizeof(b->st));
48 else if (b->fd == -1 || zend_fstat(b->fd, &b->st) == -1)
49 memset(&b->st, 0, sizeof(b->st));
50 b->fbuf = data;
51 b->flen = len;
52 b->eoff = 0;
53 b->ebuf = NULL;
54 b->elen = 0;
55 }
56
57 void
buffer_fini(struct buffer * b)58 buffer_fini(struct buffer *b)
59 {
60 efree(b->ebuf);
61 b->ebuf = NULL;
62 b->elen = 0;
63 }
64
65 int
buffer_fill(const struct buffer * bb)66 buffer_fill(const struct buffer *bb)
67 {
68 struct buffer *b = CCAST(struct buffer *, bb);
69
70 if (b->elen != 0)
71 return b->elen == FILE_BADSIZE ? -1 : 0;
72
73 if (!S_ISREG(b->st.st_mode))
74 goto out;
75
76 b->elen = CAST(size_t, b->st.st_size) < b->flen ?
77 CAST(size_t, b->st.st_size) : b->flen;
78 if (b->elen == 0) {
79 efree(b->ebuf);
80 b->ebuf = NULL;
81 return 0;
82 }
83 if ((b->ebuf = emalloc(b->elen)) == NULL)
84 goto out;
85
86 b->eoff = b->st.st_size - b->elen;
87 if (FINFO_LSEEK_FUNC(b->fd, b->eoff, SEEK_SET) == (zend_off_t)-1 ||
88 FINFO_READ_FUNC(b->fd, b->ebuf, b->elen) != (ssize_t)b->elen)
89 {
90 efree(b->ebuf);
91 b->ebuf = NULL;
92 goto out;
93 }
94
95 return 0;
96 out:
97 b->elen = FILE_BADSIZE;
98 return -1;
99 }
100
