1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
/**
* gammad -- Cooperative gamma server
* Copyright (C) 2016 Mattias Andrée (maandree@kth.se)
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "util.h"
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/**
* Duplicate a memory segment
*
* @param src The memory segment, must not be `NULL`
* @param n The size of the memory segment, must not be zero
* @return The duplicate of the memory segment,
* `NULL` on error
*/
void* memdup(const void* src, size_t n)
{
void* dest = malloc(n);
if (dest == NULL)
return NULL;
memcpy(dest, src, n);
return dest;
}
/**
* Read an entire file
*
* @param fd The file descriptor
* @param n Output for the size of the file
* @return The read content, plus a NUL byte at
* the end (not counted in `*n`)
*/
void* nread(int fd, size_t* n)
{
size_t size = 32;
ssize_t got;
struct stat st;
char* buf = NULL;
char* new;
int saved_errno;
*n = 0;
if (!fstat(fd, &st))
size = st.st_size <= 0 ? 32 : (size_t)(st.st_size);
buf = malloc(size + 1);
if (buf == NULL)
return NULL;
for (;;)
{
if (*n == size)
{
new = realloc(buf, (size <<= 1) + 1);
if (new == NULL)
goto fail;
buf = new;
}
got = read(fd, buf + *n, size - *n);
if (got < 0)
goto fail;
if (got == 0)
break;
*n += (size_t)got;
}
buf[*n] = '\0';
return buf;
fail:
saved_errno = errno;
free(buf);
errno = saved_errno;
return NULL;
}
/**
* Duplicate a file descriptor an make sure
* the new file descriptor's index as a
* specified minimum value
*
* @param fd The file descriptor
* @param atleast The least acceptable new file descriptor
* @return The new file descriptor, -1 on error
*/
int dup2atleast(int fd, int atleast)
{
int* stack = malloc((size_t)(atleast + 1) * sizeof(int));
size_t stack_ptr = 0;
int new = -1, saved_errno;
if (stack == NULL)
goto fail;
for (;;)
{
new = dup(fd);
if (new < 0)
goto fail;
if (new >= atleast)
break;
}
fail:
saved_errno = errno;
while (stack_ptr--)
close(stack[stack_ptr]);
free(stack);
errno = saved_errno;
return new;
}
|
