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  *
 216  * This function modifies the string given by the first argument by replacing
 217  * all occurrences of space and '\t' characters by '\0'. A NULL-terminated
 218  * array of pointers to char * is allocated dynamically, and these pointers are
 219  * initialized to point to the broken-up substrings.  A pointer to this array
 220  * is returned via the last argument.
 221  *
 222  * \return The number of substrings found.
 223  */
 224 unsigned split_args(char *args, char *** const argv_ptr)
 225 {
 226         char *p;
 227         char **argv;
 228         size_t n = 0, i, j;
 229         const char delim[] = " \t";
 230
 231         p = args + strspn(args, delim);
 232         for (;;) {
 233                 i = strcspn(p, delim);
 234                 if (!i)
 235                         break;
 236                 p += i;
 237                 n++;
 238                 p += strspn(p, delim);
 239         }
 240         *argv_ptr = dss_malloc((n + 1) * sizeof(char *));
 241         argv = *argv_ptr;
 242         i = 0;
 243         p = args + strspn(args, delim);
 244         while (p) {
 245                 argv[i] = p;
 246                 j = strcspn(p, delim);
 247                 if (!j)
 248                         break;
 249                 p += strcspn(p, delim);
 250                 if (*p) {
 251                         *p = '\0';
 252                         p++;
 253                         p += strspn(p, delim);
 254                 }
 255                 i++;
 256         }
 257         argv[n] = NULL;
 258         return n;
 259 }