PostgreSQL Source Code: src/common/sprompt.c Source File

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sprompt.c
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1/*-------------------------------------------------------------------------
2 *
3 * sprompt.c
4 * simple_prompt() routine
5 *
6 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/common/sprompt.c
12 *
13 *-------------------------------------------------------------------------
14 */
15#include "c.h"
16
17#include "common/fe_memutils.h"
18#include "common/string.h"
19
20#ifdef HAVE_TERMIOS_H
21#include <termios.h>
22#endif
23
24
25/*
26 * simple_prompt
27 *
28 * Generalized function especially intended for reading in usernames and
29 * passwords interactively. Reads from /dev/tty or stdin/stderr.
30 *
31 * prompt: The prompt to print, or NULL if none (automatically localized)
32 * echo: Set to false if you want to hide what is entered (for passwords)
33 *
34 * The input (without trailing newline) is returned as a malloc'd string.
35 * Caller is responsible for freeing it when done.
36 */
37char *
38 simple_prompt(const char *prompt, bool echo)
39{
40 return simple_prompt_extended(prompt, echo, NULL);
41}
42
43/*
44 * simple_prompt_extended
45 *
46 * This is the same as simple_prompt(), except that prompt_ctx can
47 * optionally be provided to allow this function to be canceled via an
48 * existing SIGINT signal handler that will longjmp to the specified place
49 * only when *(prompt_ctx->enabled) is true. If canceled, this function
50 * returns an empty string, and prompt_ctx->canceled is set to true.
51 */
52char *
53 simple_prompt_extended(const char *prompt, bool echo,
54 PromptInterruptContext *prompt_ctx)
55{
56 char *result;
57 FILE *termin,
58 *termout;
59#if defined(HAVE_TERMIOS_H)
60 struct termios t_orig,
61 t;
62#elif defined(WIN32)
63 HANDLE t = NULL;
64 DWORD t_orig = 0;
65#endif
66
67#ifdef WIN32
68
69 /*
70 * A Windows console has an "input code page" and an "output code page";
71 * these usually match each other, but they rarely match the "Windows ANSI
72 * code page" defined at system boot and expected of "char *" arguments to
73 * Windows API functions. The Microsoft CRT write() implementation
74 * automatically converts text between these code pages when writing to a
75 * console. To identify such file descriptors, it calls GetConsoleMode()
76 * on the underlying HANDLE, which in turn requires GENERIC_READ access on
77 * the HANDLE. Opening termout in mode "w+" allows that detection to
78 * succeed. Otherwise, write() would not recognize the descriptor as a
79 * console, and non-ASCII characters would display incorrectly.
80 *
81 * XXX fgets() still receives text in the console's input code page. This
82 * makes non-ASCII credentials unportable.
83 *
84 * Unintuitively, we also open termin in mode "w+", even though we only
85 * read it; that's needed for SetConsoleMode() to succeed.
86 */
87 termin = fopen("CONIN$", "w+");
88 termout = fopen("CONOUT$", "w+");
89#else
90
91 /*
92 * Do not try to collapse these into one "w+" mode file. Doesn't work on
93 * some platforms (eg, HPUX 10.20).
94 */
95 termin = fopen("/dev/tty", "r");
96 termout = fopen("/dev/tty", "w");
97#endif
98 if (!termin || !termout
99#ifdef WIN32
100
101 /*
102 * Direct console I/O does not work from the MSYS 1.0.10 console. Writes
103 * reach nowhere user-visible; reads block indefinitely. XXX This affects
104 * most Windows terminal environments, including rxvt, mintty, Cygwin
105 * xterm, Cygwin sshd, and PowerShell ISE. Switch to a more-generic test.
106 */
107 || (getenv("OSTYPE") && strcmp(getenv("OSTYPE"), "msys") == 0)
108#endif
109 )
110 {
111 if (termin)
112 fclose(termin);
113 if (termout)
114 fclose(termout);
115 termin = stdin;
116 termout = stderr;
117 }
118
119 if (!echo)
120 {
121#if defined(HAVE_TERMIOS_H)
122 /* disable echo via tcgetattr/tcsetattr */
123 tcgetattr(fileno(termin), &t);
124 t_orig = t;
125 t.c_lflag &= ~ECHO;
126 tcsetattr(fileno(termin), TCSAFLUSH, &t);
127#elif defined(WIN32)
128 /* need the file's HANDLE to turn echo off */
129 t = (HANDLE) _get_osfhandle(_fileno(termin));
130
131 /* save the old configuration first */
132 GetConsoleMode(t, &t_orig);
133
134 /* set to the new mode */
135 SetConsoleMode(t, ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT);
136#endif
137 }
138
139 if (prompt)
140 {
141 fputs(_(prompt), termout);
142 fflush(termout);
143 }
144
145 result = pg_get_line(termin, prompt_ctx);
146
147 /* If we failed to read anything, just return an empty string */
148 if (result == NULL)
149 result = pg_strdup("");
150
151 /* strip trailing newline, including \r in case we're on Windows */
152 (void) pg_strip_crlf(result);
153
154 if (!echo)
155 {
156 /* restore previous echo behavior, then echo \n */
157#if defined(HAVE_TERMIOS_H)
158 tcsetattr(fileno(termin), TCSAFLUSH, &t_orig);
159 fputs("\n", termout);
160 fflush(termout);
161#elif defined(WIN32)
162 SetConsoleMode(t, t_orig);
163 fputs("\n", termout);
164 fflush(termout);
165#endif
166 }
167 else if (prompt_ctx && prompt_ctx->canceled)
168 {
169 /* also echo \n if prompt was canceled */
170 fputs("\n", termout);
171 fflush(termout);
172 }
173
174 if (termin != stdin)
175 {
176 fclose(termin);
177 fclose(termout);
178 }
179
180 return result;
181}
_
#define _(x)
Definition: elog.c:91
char * pg_strdup(const char *in)
Definition: fe_memutils.c:85
char * pg_get_line(FILE *stream, PromptInterruptContext *prompt_ctx)
Definition: pg_get_line.c:59
char * simple_prompt_extended(const char *prompt, bool echo, PromptInterruptContext *prompt_ctx)
Definition: sprompt.c:53
char * simple_prompt(const char *prompt, bool echo)
Definition: sprompt.c:38
int pg_strip_crlf(char *str)
Definition: string.c:154

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