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utils-std

Collection of commonly available Unix tools git clone https://anongit.hacktivis.me/git/utils-std.git

consent.c (3223B)

    

  1. // utils-std: Collection of commonly available Unix tools
  2. // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
  3. // SPDX-License-Identifier: MPL-2.0
  5. #define _POSIX_C_SOURCE 200809L
  7. #include "./consent.h"
  9. #include <assert.h>
  10. #include <errno.h>
  11. #include <langinfo.h> // nl_langinfo
  12. #include <regex.h>    // regcomp
  13. #include <stdarg.h>   // va_list
  14. #include <stdio.h>    // fprintf, getline,
  15. #include <stdlib.h>   // free
  16. #include <string.h>   // strerror
  17. #include <unistd.h>   // isatty, write
  19. // Needs to be executed after setlocale
  20. regex_t consent_yesexpr_r;
  21. regex_t consent_noexpr_r;
  22. void
  23. consent_init(void)
  24. {
  25. 	char *yesexpr = nl_langinfo(YESEXPR);
  26. 	int yesexpr_ret = regcomp(&consent_yesexpr_r, yesexpr, REG_EXTENDED | REG_NOSUB);
  27. 	if(yesexpr_ret != 0)
  28. 	{
  29. 		char errstr[64] = "";
  30. 		regerror(yesexpr_ret, &consent_yesexpr_r, errstr, 100);
  31. 		fprintf(
  32. 		    stderr, "%s: Got errorneous yesexpr regex /%s/ from locale: %s\n", argv0, yesexpr, errstr);
  34. 		errno = 0;
  35. 		fprintf(stderr, "%s: Fallbacking to /^[Yy]/\n", argv0);
  36. 		yesexpr_ret = regcomp(&consent_yesexpr_r, "^[Yy]", REG_EXTENDED | REG_NOSUB);
  37. 		assert(yesexpr_ret == 0);
  38. 	}
  39. 	assert(errno == 0);
  41. 	char *noexpr = nl_langinfo(NOEXPR);
  42. 	int noexpr_ret = regcomp(&consent_noexpr_r, noexpr, REG_EXTENDED | REG_NOSUB);
  43. 	if(noexpr_ret != 0)
  44. 	{
  45. 		char errstr[64] = "";
  46. 		regerror(noexpr_ret, &consent_noexpr_r, errstr, 100);
  47. 		fprintf(
  48. 		    stderr, "%s: Got errorneous noexpr regex /%s/ from locale: %s\n", argv0, noexpr, errstr);
  50. 		errno = 0;
  51. 		fprintf(stderr, "%s: Fallbacking to /^[Nn]/\n", argv0);
  52. 		noexpr_ret = regcomp(&consent_noexpr_r, "^[Nn]", REG_EXTENDED | REG_NOSUB);
  53. 		assert(noexpr_ret == 0);
  54. 	}
  55. 	assert(errno == 0);
  56. }
  58. void
  59. consent_finish(void)
  60. {
  61. 	regfree(&consent_yesexpr_r);
  62. 	regfree(&consent_noexpr_r);
  63. }
  65. // Consent therefore defaults to no
  66. bool
  67. consentf(const char *restrict fmt, ...)
  68. {
  69. 	bool result = false;
  70. 	char *line = NULL;
  71. 	size_t len = 0;
  73. 	va_list ap;
  75. 	assert(errno == 0);
  76. 	va_start(ap, fmt);
  77. 	int ret = vfprintf(stderr, fmt, ap);
  78. 	va_end(ap);
  80. 	if(ret < 0)
  81. 	{
  82. 		fprintf(stderr, "%s: Failed to print user prompt: %s\n", argv0, strerror(errno));
  83. 		errno = 0;
  84. 		goto end;
  85. 	}
  87. 	assert(errno == 0);
  88. 	ssize_t nread = getline(&line, &len, stdin);
  89. 	if(nread < 0)
  90. 	{
  91. 		fprintf(stderr, "\n%s: Failed getting user entry via getline: %s\n", argv0, strerror(errno));
  92. 		errno = 0;
  93. 		goto end;
  94. 	}
  96. 	if(nread == 0)
  97. 	{
  98. 		fprintf(stderr, "%s: Got empty response, considering it false\n", argv0);
  99. 		errno = 0;
  100. 		goto end;
  101. 	}
  103. 	// Doesn't echoes if not a TTY
  104. 	if(!isatty(0)) write(2, line, nread);
  105. 	// isatty changes errno if not a TTY *sigh*
  106. 	errno = 0;
  108. 	if(line[nread - 1] == '\n') line[--nread] = 0;
  110. 	if(line[0] == 0 || line[0] == '\n' || line[0] == '\r')
  111. 	{
  112. 		fprintf(stderr, "%s: Got empty response, considering it false\n", argv0);
  113. 		goto end;
  114. 	}
  116. 	if(regexec(&consent_yesexpr_r, line, 0, 0, 0) == 0)
  117. 	{
  118. 		result = true;
  119. 		goto end;
  120. 	}
  122. 	if(regexec(&consent_noexpr_r, line, 0, 0, 0) == 0)
  123. 	{
  124. 		result = false;
  125. 		goto end;
  126. 	}
  128. 	fprintf(stderr,
  129. 	        "%s: User entry \"%s\" neither affirmative nor negative, considering it false\n",
  130. 	        argv0,
  131. 	        line);
  133. end:
  134. 	if(len != 0) free(line);
  135. 	return result;
  136. }