1 /* getdelim.c --- Implementation of replacement getdelim function.
2 Copyright (C) 1994, 1996-1998, 2001, 2003, 2005-2023 Free Software
3 Foundation, Inc.
4
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 This file is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 /* Ported from glibc by Simon Josefsson. */
19
20 /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
21 optimizes away the lineptr == NULL || n == NULL || fp == NULL tests below. */
22 #define _GL_ARG_NONNULL(params)
23
24 #include <config.h>
25
26 #include <stdio.h>
27
28 #include <limits.h>
29 #include <stdint.h>
30 #include <stdlib.h>
31 #include <errno.h>
32
33 #if USE_UNLOCKED_IO
34 # include "unlocked-io.h"
35 # define getc_maybe_unlocked(fp) getc(fp)
36 #elif !HAVE_FLOCKFILE || !HAVE_FUNLOCKFILE || !HAVE_DECL_GETC_UNLOCKED
37 # undef flockfile
38 # undef funlockfile
39 # define flockfile(x) ((void) 0)
40 # define funlockfile(x) ((void) 0)
41 # define getc_maybe_unlocked(fp) getc(fp)
42 #else
43 # define getc_maybe_unlocked(fp) getc_unlocked(fp)
44 #endif
45
46 static void
47 alloc_failed (void)
48 {
49 #if defined _WIN32 && ! defined __CYGWIN__
50 /* Avoid errno problem without using the realloc module; see:
51 https://lists.gnu.org/r/bug-gnulib/2016-08/msg00025.html */
52 errno = ENOMEM;
53 #endif
54 }
55
56 /* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
57 NUL-terminate it). *LINEPTR is a pointer returned from malloc (or
58 NULL), pointing to *N characters of space. It is realloc'ed as
59 necessary. Returns the number of characters read (not including
60 the null terminator), or -1 on error or EOF. */
61
62 ssize_t
63 getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
64 {
65 ssize_t result;
66 size_t cur_len = 0;
67
68 if (lineptr == NULL || n == NULL || fp == NULL)
69 {
70 errno = EINVAL;
71 return -1;
72 }
73
74 flockfile (fp);
75
76 if (*lineptr == NULL || *n == 0)
77 {
78 char *new_lineptr;
79 *n = 120;
80 new_lineptr = (char *) realloc (*lineptr, *n);
81 if (new_lineptr == NULL)
82 {
83 alloc_failed ();
84 result = -1;
85 goto unlock_return;
86 }
87 *lineptr = new_lineptr;
88 }
89
90 for (;;)
91 {
92 int i;
93
94 i = getc_maybe_unlocked (fp);
95 if (i == EOF)
96 {
97 result = -1;
98 break;
99 }
100
101 /* Make enough space for len+1 (for final NUL) bytes. */
102 if (cur_len + 1 >= *n)
103 {
104 size_t needed_max =
105 SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
106 size_t needed = 2 * *n + 1; /* Be generous. */
107 char *new_lineptr;
108
109 if (needed_max < needed)
110 needed = needed_max;
111 if (cur_len + 1 >= needed)
112 {
113 result = -1;
114 errno = EOVERFLOW;
115 goto unlock_return;
116 }
117
118 new_lineptr = (char *) realloc (*lineptr, needed);
119 if (new_lineptr == NULL)
120 {
121 alloc_failed ();
122 result = -1;
123 goto unlock_return;
124 }
125
126 *lineptr = new_lineptr;
127 *n = needed;
128 }
129
130 (*lineptr)[cur_len] = i;
131 cur_len++;
132
133 if (i == delimiter)
134 break;
135 }
136 (*lineptr)[cur_len] = '\0';
137 result = cur_len ? cur_len : result;
138
139 unlock_return:
140 funlockfile (fp); /* doesn't set errno */
141
142 return result;
143 }