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 }