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utils-std

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

consent.c (3326B)

    

  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(stderr,
  32. 		        "%s: warning: Got erroneous yesexpr regex /%s/ from locale: %s\n",
  33. 		        argv0,
  34. 		        yesexpr,
  35. 		        errstr);
  37. 		errno = 0;
  38. 		fprintf(stderr, "%s: Fallbacking to /^[Yy]/\n", argv0);
  39. 		yesexpr_ret = regcomp(&consent_yesexpr_r, "^[Yy]", REG_EXTENDED | REG_NOSUB);
  40. 		assert(yesexpr_ret == 0);
  41. 	}
  42. 	assert(errno == 0);
  44. 	char *noexpr = nl_langinfo(NOEXPR);
  45. 	int noexpr_ret = regcomp(&consent_noexpr_r, noexpr, REG_EXTENDED | REG_NOSUB);
  46. 	if(noexpr_ret != 0)
  47. 	{
  48. 		char errstr[64] = "";
  49. 		regerror(noexpr_ret, &consent_noexpr_r, errstr, 100);
  50. 		fprintf(stderr,
  51. 		        "%s: warning: Got erroneous noexpr regex /%s/ from locale: %s\n",
  52. 		        argv0,
  53. 		        noexpr,
  54. 		        errstr);
  56. 		errno = 0;
  57. 		fprintf(stderr, "%s: Fallbacking to /^[Nn]/\n", argv0);
  58. 		noexpr_ret = regcomp(&consent_noexpr_r, "^[Nn]", REG_EXTENDED | REG_NOSUB);
  59. 		assert(noexpr_ret == 0);
  60. 	}
  61. 	assert(errno == 0);
  62. }
  64. void
  65. consent_finish(void)
  66. {
  67. 	regfree(&consent_yesexpr_r);
  68. 	regfree(&consent_noexpr_r);
  69. }
  71. // Consent therefore defaults to no
  72. bool
  73. consentf(const char *restrict fmt, ...)
  74. {
  75. 	bool result = false;
  76. 	char *line = NULL;
  77. 	size_t len = 0;
  79. 	va_list ap;
  81. 	assert(errno == 0);
  82. 	va_start(ap, fmt);
  83. 	int ret = vfprintf(stderr, fmt, ap);
  84. 	va_end(ap);
  86. 	if(ret < 0)
  87. 	{
  88. 		fprintf(stderr, "%s: error: Failed to print user prompt: %s\n", argv0, strerror(errno));
  89. 		errno = 0;
  90. 		goto end;
  91. 	}
  93. 	assert(errno == 0);
  94. 	ssize_t nread = getline(&line, &len, stdin);
  95. 	if(nread < 0)
  96. 	{
  97. 		fprintf(
  98. 		    stderr, "\n%s: error: Failed getting user entry via getline: %s\n", argv0, strerror(errno));
  99. 		errno = 0;
  100. 		goto end;
  101. 	}
  103. 	if(nread == 0)
  104. 	{
  105. 		fprintf(stderr, "%s: Got empty response, considering it false\n", argv0);
  106. 		errno = 0;
  107. 		goto end;
  108. 	}
  110. 	// Doesn't echoes if not a TTY
  111. 	if(!isatty(0)) write(2, line, nread);
  112. 	// isatty changes errno if not a TTY *sigh*
  113. 	errno = 0;
  115. 	if(line[nread - 1] == '\n') line[--nread] = 0;
  117. 	if(line[0] == 0 || line[0] == '\n' || line[0] == '\r')
  118. 	{
  119. 		fprintf(stderr, "%s: Got empty response, considering it false\n", argv0);
  120. 		goto end;
  121. 	}
  123. 	if(regexec(&consent_yesexpr_r, line, 0, 0, 0) == 0)
  124. 	{
  125. 		result = true;
  126. 		goto end;
  127. 	}
  129. 	if(regexec(&consent_noexpr_r, line, 0, 0, 0) == 0)
  130. 	{
  131. 		result = false;
  132. 		goto end;
  133. 	}
  135. 	fprintf(stderr,
  136. 	        "%s: User entry \"%s\" neither affirmative nor negative, considering it false\n",
  137. 	        argv0,
  138. 	        line);
  140. end:
  141. 	if(len != 0) free(line);
  142. 	return result;
  143. }