dss.ggo: Minor documentation improvements.
[dss.git] / string.c
1 #include <string.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5 #include <limits.h>
6 #include <errno.h>
7 #include <pwd.h>
8 #include <sys/types.h>
9 #include <unistd.h>
10
11
12 #include "cmdline.h"
13 #include "gcc-compat.h"
14 #include "log.h"
15 #include "error.h"
16 #include "string.h"
17
18 __noreturn void clean_exit(int status);
19
20 /**
21 * Write a message to a dynamically allocated string.
22 *
23 * \param fmt Usual format string.
24 * \param p Result pointer.
25 *
26 * \sa printf(3). */
27 #define VSPRINTF(fmt, p) \
28 { \
29 int n; \
30 size_t size = 100; \
31 p = dss_malloc(size); \
32 while (1) { \
33 va_list ap; \
34 /* Try to print in the allocated space. */ \
35 va_start(ap, fmt); \
36 n = vsnprintf(p, size, fmt, ap); \
37 va_end(ap); \
38 /* If that worked, return the string. */ \
39 if (n > -1 && n < size) \
40 break; \
41 /* Else try again with more space. */ \
42 if (n > -1) /* glibc 2.1 */ \
43 size = n + 1; /* precisely what is needed */ \
44 else /* glibc 2.0 */ \
45 size *= 2; /* twice the old size */ \
46 p = dss_realloc(p, size); \
47 } \
48 }
49
50 /**
51 * dss' version of realloc().
52 *
53 * \param p Pointer to the memory block, may be \p NULL.
54 * \param size The desired new size.
55 *
56 * A wrapper for realloc(3). It calls \p exit(\p EXIT_FAILURE) on errors,
57 * i.e. there is no need to check the return value in the caller.
58 *
59 * \return A pointer to the newly allocated memory, which is suitably aligned
60 * for any kind of variable and may be different from \a p.
61 *
62 * \sa realloc(3).
63 */
64 __must_check __malloc void *dss_realloc(void *p, size_t size)
65 {
66 /*
67 * No need to check for NULL pointers: If p is NULL, the call
68 * to realloc is equivalent to malloc(size)
69 */
70 assert(size);
71 if (!(p = realloc(p, size))) {
72 DSS_EMERG_LOG("realloc failed (size = %zu), aborting\n",
73 size);
74 clean_exit(EXIT_FAILURE);
75 }
76 return p;
77 }
78
79 /**
80 * dss' version of malloc().
81 *
82 * \param size The desired new size.
83 *
84 * A wrapper for malloc(3) which exits on errors.
85 *
86 * \return A pointer to the allocated memory, which is suitably aligned for any
87 * kind of variable.
88 *
89 * \sa malloc(3).
90 */
91 __must_check __malloc void *dss_malloc(size_t size)
92 {
93 assert(size);
94 void *p = malloc(size);
95
96 if (!p) {
97 DSS_EMERG_LOG("malloc failed (size = %zu), aborting\n",
98 size);
99 clean_exit(EXIT_FAILURE);
100 }
101 return p;
102 }
103
104 /**
105 * dss' version of calloc().
106 *
107 * \param size The desired new size.
108 *
109 * A wrapper for calloc(3) which exits on errors.
110 *
111 * \return A pointer to the allocated and zeroed-out memory, which is suitably
112 * aligned for any kind of variable.
113 *
114 * \sa calloc(3)
115 */
116 __must_check __malloc void *dss_calloc(size_t size)
117 {
118 void *ret = dss_malloc(size);
119
120 memset(ret, 0, size);
121 return ret;
122 }
123
124 /**
125 * dss' version of strdup().
126 *
127 * \param s The string to be duplicated.
128 *
129 * A wrapper for strdup(3). It calls \p exit(EXIT_FAILURE) on errors, i.e.
130 * there is no need to check the return value in the caller.
131 *
132 * \return A pointer to the duplicated string. If \p s was the NULL pointer,
133 * an pointer to an empty string is returned.
134 *
135 * \sa strdup(3)
136 */
137
138 __must_check __malloc char *dss_strdup(const char *s)
139 {
140 char *ret;
141
142 if ((ret = strdup(s? s: "")))
143 return ret;
144 DSS_EMERG_LOG("strdup failed, aborting\n");
145 clean_exit(EXIT_FAILURE);
146 }
147
148 /**
149 * Allocate a sufficiently large string and print into it.
150 *
151 * \param fmt A usual format string.
152 *
153 * Produce output according to \p fmt. No artificial bound on the length of the
154 * resulting string is imposed.
155 *
156 * \return This function either returns a pointer to a string that must be
157 * freed by the caller or aborts without returning.
158 *
159 * \sa printf(3).
160 */
161 __must_check __printf_1_2 __malloc char *make_message(const char *fmt, ...)
162 {
163 char *msg;
164
165 VSPRINTF(fmt, msg);
166 return msg;
167 }
168
169 __printf_1_2 void make_err_msg(const char* fmt,...)
170 {
171 free(dss_error_txt);
172 VSPRINTF(fmt, dss_error_txt);
173 }
174
175 /**
176 * Get the home directory of the current user.
177 *
178 * \return A dynammically allocated string that must be freed by the caller. If
179 * the home directory could not be found, this function returns "/tmp".
180 */
181 __must_check __malloc char *get_homedir(void)
182 {
183 struct passwd *pw = getpwuid(getuid());
184 return dss_strdup(pw? pw->pw_dir : "/tmp");
185 }
186
187 /**
188 * Convert a string to a 64-bit signed integer value.
189 *
190 * \param str The string to be converted.
191 * \param value Result pointer.
192 *
193 * \return Standard.
194 *
195 * \sa strtol(3), atoi(3).
196 */
197 int dss_atoi64(const char *str, int64_t *value)
198 {
199 char *endptr;
200 long long tmp;
201
202 errno = 0; /* To distinguish success/failure after call */
203 tmp = strtoll(str, &endptr, 10);
204 if (errno == ERANGE && (tmp == LLONG_MAX || tmp == LLONG_MIN)) {
205 make_err_msg("%s", str);
206 return -E_ATOI_OVERFLOW;
207 }
208 if (errno != 0 && tmp == 0) { /* other error */
209 make_err_msg("%s", str);
210 return -E_STRTOLL;
211 }
212 if (endptr == str) {
213 make_err_msg("%s", str);
214 return -E_ATOI_NO_DIGITS;
215 }
216 if (*endptr != '\0') { /* Further characters after number */
217 make_err_msg("%s", str);
218 return -E_ATOI_JUNK_AT_END;
219 }
220 *value = tmp;
221 return 1;
222 }
223
224 /**
225 * Get the logname of the current user.
226 *
227 * \return A dynammically allocated string that must be freed by the caller. On
228 * errors, the string "unknown user" is returned, i.e. this function never
229 * returns \p NULL.
230 *
231 * \sa getpwuid(3).
232 */
233 __must_check __malloc char *dss_logname(void)
234 {
235 struct passwd *pw = getpwuid(getuid());
236 return dss_strdup(pw? pw->pw_name : "unknown_user");
237 }
238
239 /**
240 * Split string and return pointers to its parts.
241 *
242 * \param args The string to be split.
243 * \param argv_ptr Pointer to the list of substrings.
244 * \param delim Delimiter.
245 *
246 * This function modifies \a args by replacing each occurance of \a delim by
247 * zero. A \p NULL-terminated array of pointers to char* is allocated dynamically
248 * and these pointers are initialized to point to the broken-up substrings
249 * within \a args. A pointer to this array is returned via \a argv_ptr.
250 *
251 * \return The number of substrings found in \a args.
252 */
253 __must_check unsigned split_args(char *args, char *** const argv_ptr, const char *delim)
254 {
255 char *p = args;
256 char **argv;
257 size_t n = 0, i, j;
258
259 p = args + strspn(args, delim);
260 for (;;) {
261 i = strcspn(p, delim);
262 if (!i)
263 break;
264 p += i;
265 n++;
266 p += strspn(p, delim);
267 }
268 *argv_ptr = dss_malloc((n + 1) * sizeof(char *));
269 argv = *argv_ptr;
270 i = 0;
271 p = args + strspn(args, delim);
272 while (p) {
273 argv[i] = p;
274 j = strcspn(p, delim);
275 if (!j)
276 break;
277 p += strcspn(p, delim);
278 if (*p) {
279 *p = '\0';
280 p++;
281 p += strspn(p, delim);
282 }
283 i++;
284 }
285 argv[n] = NULL;
286 return n;
287 }