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