1/*
2 * This file contains helper functions for labeling support.
3 *
4 * Author : Richard Haines <richard_c_haines@btinternet.com>
5 */
6
7#include <stdlib.h>
8#include <stdarg.h>
9#include <ctype.h>
10#include <string.h>
11#include <errno.h>
12#include "label_internal.h"
13
14/*
15 * The read_spec_entries and read_spec_entry functions may be used to
16 * replace sscanf to read entries from spec files. The file and
17 * property services now use these.
18 */
19
20/*
21 * Read an entry from a spec file (e.g. file_contexts)
22 * entry - Buffer to allocate for the entry.
23 * ptr - current location of the line to be processed.
24 * returns  - 0 on success and *entry is set to be a null
25 *            terminated value. On Error it returns -1 and
26              errno will be set.
27 *
28 */
29static inline int read_spec_entry(char **entry, char **ptr, int *len, const char **errbuf)
30{
31	*entry = NULL;
32	char *tmp_buf = NULL;
33
34	while (isspace(**ptr) && **ptr != '\0')
35		(*ptr)++;
36
37	tmp_buf = *ptr;
38	*len = 0;
39
40	while (!isspace(**ptr) && **ptr != '\0') {
41		if (!isascii(**ptr)) {
42			errno = EINVAL;
43			*errbuf = "Non-ASCII characters found";
44			return -1;
45		}
46		(*ptr)++;
47		(*len)++;
48	}
49
50	if (*len) {
51		*entry = strndup(tmp_buf, *len);
52		if (!*entry)
53			return -1;
54	}
55
56	return 0;
57}
58
59/*
60 * line_buf - Buffer containing the spec entries .
61 * errbuf   - Double pointer used for passing back specific error messages.
62 * num_args - The number of spec parameter entries to process.
63 * ...      - A 'char **spec_entry' for each parameter.
64 * returns  - The number of items processed. On error, it returns -1 with errno
65 *            set and may set errbuf to a specific error message.
66 *
67 * This function calls read_spec_entry() to do the actual string processing.
68 * As such, can return anything from that function as well.
69 */
70int hidden read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...)
71{
72	char **spec_entry, *buf_p;
73	int len, rc, items, entry_len = 0;
74	va_list ap;
75
76	*errbuf = NULL;
77
78	len = strlen(line_buf);
79	if (line_buf[len - 1] == '\n')
80		line_buf[len - 1] = '\0';
81	else
82		/* Handle case if line not \n terminated by bumping
83		 * the len for the check below (as the line is NUL
84		 * terminated by getline(3)) */
85		len++;
86
87	buf_p = line_buf;
88	while (isspace(*buf_p))
89		buf_p++;
90
91	/* Skip comment lines and empty lines. */
92	if (*buf_p == '#' || *buf_p == '\0')
93		return 0;
94
95	/* Process the spec file entries */
96	va_start(ap, num_args);
97
98	items = 0;
99	while (items < num_args) {
100		spec_entry = va_arg(ap, char **);
101
102		if (len - 1 == buf_p - line_buf) {
103			va_end(ap);
104			return items;
105		}
106
107		rc = read_spec_entry(spec_entry, &buf_p, &entry_len, errbuf);
108		if (rc < 0) {
109			va_end(ap);
110			return rc;
111		}
112		if (entry_len)
113			items++;
114	}
115	va_end(ap);
116	return items;
117}
118