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[dss.git] / str.c
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <string.h>
3 #include <stdlib.h>
4 #include <stdio.h>
5 #include <stdarg.h>
6 #include <assert.h>
7 #include <limits.h>
8 #include <errno.h>
9 #include <pwd.h>
10 #include <sys/types.h>
11 #include <unistd.h>
12
13
14 #include "gcc-compat.h"
15 #include "log.h"
16 #include "err.h"
17 #include "str.h"
18
19 /**
20 * dss' version of realloc().
21 *
22 * \param p Pointer to the memory block, may be \p NULL.
23 * \param size The desired new size.
24 *
25 * A wrapper for realloc(3). It calls \p exit(\p EXIT_FAILURE) on errors,
26 * i.e. there is no need to check the return value in the caller.
27 *
28 * \return A pointer to the newly allocated memory, which is suitably aligned
29 * for any kind of variable and may be different from \a p.
30 *
31 * \sa realloc(3).
32 */
33 __must_check __malloc void *dss_realloc(void *p, size_t size)
34 {
35 /*
36 * No need to check for NULL pointers: If p is NULL, the call
37 * to realloc is equivalent to malloc(size)
38 */
39 assert(size);
40 if (!(p = realloc(p, size))) {
41 DSS_EMERG_LOG(("realloc failed (size = %zu), aborting\n",
42 size));
43 exit(EXIT_FAILURE);
44 }
45 return p;
46 }
47
48 /**
49 * dss' version of malloc().
50 *
51 * \param size The desired new size.
52 *
53 * A wrapper for malloc(3) which exits on errors.
54 *
55 * \return A pointer to the allocated memory, which is suitably aligned for any
56 * kind of variable.
57 *
58 * \sa malloc(3).
59 */
60 __must_check __malloc void *dss_malloc(size_t size)
61 {
62 void *p;
63 assert(size);
64 p = malloc(size);
65
66 if (!p) {
67 DSS_EMERG_LOG(("malloc failed (size = %zu), aborting\n",
68 size));
69 exit(EXIT_FAILURE);
70 }
71 return p;
72 }
73
74 /**
75 * dss' version of calloc().
76 *
77 * \param size The desired new size.
78 *
79 * A wrapper for calloc(3) which exits on errors.
80 *
81 * \return A pointer to the allocated and zeroed-out memory, which is suitably
82 * aligned for any kind of variable.
83 *
84 * \sa calloc(3)
85 */
86 __must_check __malloc void *dss_calloc(size_t size)
87 {
88 void *ret = dss_malloc(size);
89
90 memset(ret, 0, size);
91 return ret;
92 }
93
94 /**
95 * dss' version of strdup().
96 *
97 * \param s The string to be duplicated.
98 *
99 * A wrapper for strdup(3). It calls \p exit(EXIT_FAILURE) on errors, i.e.
100 * there is no need to check the return value in the caller.
101 *
102 * \return A pointer to the duplicated string. If \p s was the NULL pointer,
103 * an pointer to an empty string is returned.
104 *
105 * \sa strdup(3)
106 */
107
108 __must_check __malloc char *dss_strdup(const char *s)
109 {
110 char *ret;
111
112 if ((ret = strdup(s? s: "")))
113 return ret;
114 DSS_EMERG_LOG(("strdup failed, aborting\n"));
115 exit(EXIT_FAILURE);
116 }
117
118 /**
119 * Allocate a sufficiently large string and print into it.
120 *
121 * \param fmt A usual format string.
122 *
123 * Produce output according to \p fmt. No artificial bound on the length of the
124 * resulting string is imposed.
125 *
126 * \return This function either returns a pointer to a string that must be
127 * freed by the caller or aborts without returning.
128 *
129 * \sa printf(3).
130 */
131 __must_check __printf_1_2 __malloc char *make_message(const char *fmt, ...)
132 {
133 char *msg;
134 size_t size = 100;
135
136 msg = dss_malloc(size);
137 while (1) {
138 int n;
139 va_list ap;
140
141 /* Try to print in the allocated space. */
142 va_start(ap, fmt);
143 n = vsnprintf(msg, size, fmt, ap);
144 va_end(ap);
145 /* If that worked, return the string. */
146 if (n < size)
147 return msg;
148 /* Else try again with more space. */
149 size = n + 1; /* precisely what is needed */
150 msg = dss_realloc(msg, size);
151 }
152 }
153
154 /**
155 * Get the home directory of the current user.
156 *
157 * \return A dynamically allocated string that must be freed by the caller. If
158 * the home directory could not be found, this function returns "/tmp".
159 */
160 __must_check __malloc char *get_homedir(void)
161 {
162 struct passwd *pw = getpwuid(getuid());
163 return dss_strdup(pw? pw->pw_dir : "/tmp");
164 }
165
166 /**
167 * Convert a string to a 64-bit signed integer value.
168 *
169 * \param str The string to be converted.
170 * \param value Result pointer.
171 *
172 * \return Standard.
173 *
174 * \sa strtol(3), atoi(3).
175 */
176 int dss_atoi64(const char *str, int64_t *value)
177 {
178 char *endptr;
179 long long tmp;
180
181 errno = 0; /* To distinguish success/failure after call */
182 tmp = strtoll(str, &endptr, 10);
183 if (errno == ERANGE && (tmp == LLONG_MAX || tmp == LLONG_MIN))
184 return -E_ATOI_OVERFLOW;
185 if (errno != 0 && tmp == 0) /* other error */
186 return -E_STRTOLL;
187 if (endptr == str)
188 return -E_ATOI_NO_DIGITS;
189 if (*endptr != '\0') /* Further characters after number */
190 return -E_ATOI_JUNK_AT_END;
191 *value = tmp;
192 return 1;
193 }
194
195 /**
196 * Get the logname of the current user.
197 *
198 * \return A dynamically allocated string that must be freed by the caller. On
199 * errors, the string "unknown user" is returned, i.e. this function never
200 * returns \p NULL.
201 *
202 * \sa getpwuid(3).
203 */
204 __must_check __malloc char *dss_logname(void)
205 {
206 struct passwd *pw = getpwuid(getuid());
207 return dss_strdup(pw? pw->pw_name : "unknown_user");
208 }
209
210 /**
211 * Split string and return pointers to its parts.
212 *
213 * \param args The string to be split.
214 * \param argv_ptr Pointer to the list of substrings.
215 * \param delim Delimiter.
216 *
217 * This function modifies \a args by replacing each occurrence of \a delim by
218 * zero. A \p NULL-terminated array of pointers to char* is allocated dynamically
219 * and these pointers are initialized to point to the broken-up substrings
220 * within \a args. A pointer to this array is returned via \a argv_ptr.
221 *
222 * \return The number of substrings found in \a args.
223 */
224 unsigned split_args(char *args, char *** const argv_ptr, const char *delim)
225 {
226 char *p;
227 char **argv;
228 size_t n = 0, i, j;
229
230 p = args + strspn(args, delim);
231 for (;;) {
232 i = strcspn(p, delim);
233 if (!i)
234 break;
235 p += i;
236 n++;
237 p += strspn(p, delim);
238 }
239 *argv_ptr = dss_malloc((n + 1) * sizeof(char *));
240 argv = *argv_ptr;
241 i = 0;
242 p = args + strspn(args, delim);
243 while (p) {
244 argv[i] = p;
245 j = strcspn(p, delim);
246 if (!j)
247 break;
248 p += strcspn(p, delim);
249 if (*p) {
250 *p = '\0';
251 p++;
252 p += strspn(p, delim);
253 }
254 i++;
255 }
256 argv[n] = NULL;
257 return n;
258 }