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nuttx-apps/system/readline/readline_common.c
Alin Jerpelea 967e7e2912 system: readline: Improve security
2020-01-08 20:43:39 +08:00

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/****************************************************************************
* apps/system/readline/readline_common.c
*
* Copyright (C) 2007-2008, 2011-2013, 2015 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdbool.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/ascii.h>
#include <nuttx/vt100.h>
#include <nuttx/lib/builtin.h>
#include "system/readline.h"
#include "readline.h"
/****************************************************************************
* Private Data
****************************************************************************/
/* <esc>[K is the VT100 command erases to the end of the line. */
static const char g_erasetoeol[] = VT100_CLEAREOL;
#ifdef CONFIG_READLINE_TABCOMPLETION
/* Prompt string to present at the beginning of the line */
static FAR const char *g_readline_prompt = NULL;
#ifdef CONFIG_READLINE_HAVE_EXTMATCH
static FAR const struct extmatch_vtable_s *g_extmatch_vtbl = NULL;
#endif
#endif /* CONFIG_READLINE_TABCOMPLETION */
#ifdef CONFIG_READLINE_CMD_HISTORY
/* Nghia Ho: command history
*
* g_cmd_history[][] Circular buffer
* g_cmd_history_head Head of the circular buffer, most recent command
* g_cmd_history_steps_from_head Offset from head
* g_cmd_history_len Number of elements in the circular buffer
*/
static char g_cmd_history[CONFIG_READLINE_CMD_HISTORY_LEN][CONFIG_READLINE_CMD_HISTORY_LINELEN];
static int g_cmd_history_head = -1;
static int g_cmd_history_steps_from_head = 1;
static int g_cmd_history_len = 0;
#endif /* CONFIG_READLINE_CMD_HISTORY */
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: count_builtin_matches
*
* Description:
* Count the number of builtin commands
*
* Input Parameters:
* matches - Array to save builtin command index.
* len - The length of the matching name to try
*
* Returned Value:
* The number of matching names
*
****************************************************************************/
#if defined(CONFIG_READLINE_TABCOMPLETION) && defined(CONFIG_BUILTIN)
static int count_builtin_matches(FAR char *buf, FAR int *matches, int namelen)
{
#if CONFIG_READLINE_MAX_BUILTINS > 0
FAR const char *name;
int nr_matches = 0;
int i;
for (i = 0; (name = builtin_getname(i)) != NULL; i++)
{
if (strncmp(buf, name, namelen) == 0)
{
matches[nr_matches] = i;
nr_matches++;
if (nr_matches >= CONFIG_READLINE_MAX_BUILTINS)
{
break;
}
}
}
return nr_matches;
#else
return 0;
#endif
}
#endif
/****************************************************************************
* Name: tab_completion
*
* Description:
* Nghia - Unix like tab completion, only for builtin apps
*
* Input Parameters:
* vtbl - vtbl used to access implementation specific interface
* buf - The user allocated buffer to be filled.
* buflen - the size of the buffer.
* nch - the number of characters.
*
* Returned Value:
* None.
*
****************************************************************************/
#ifdef CONFIG_READLINE_TABCOMPLETION
static void tab_completion(FAR struct rl_common_s *vtbl, char *buf,
int buflen, int *nch)
{
FAR const char *name = NULL;
char tmp_name[CONFIG_TASK_NAME_SIZE + 1];
#ifdef CONFIG_BUILTIN
int nr_builtin_matches = 0;
int builtin_matches[CONFIG_READLINE_MAX_BUILTINS];
#endif
#ifdef CONFIG_READLINE_HAVE_EXTMATCH
int nr_ext_matches = 0;
int ext_matches[CONFIG_READLINE_MAX_EXTCMDS];
#endif
int nr_matches;
int len = *nch;
int name_len;
int i;
int j;
if (len >= 1)
{
#ifdef CONFIG_BUILTIN
/* Count the matching builtin commands */
nr_builtin_matches = count_builtin_matches(buf, builtin_matches, len);
nr_matches = nr_builtin_matches;
#else
nr_matches = 0;
#endif
#ifdef CONFIG_READLINE_HAVE_EXTMATCH
/* Is there registered external handling logic? */
nr_ext_matches = 0;
if (g_extmatch_vtbl != NULL)
{
/* Count the number of external commands */
nr_ext_matches = g_extmatch_vtbl->count_matches(buf, ext_matches, len);
nr_matches += nr_ext_matches;
}
#endif
/* Is there only one matching name? */
if (nr_matches == 1)
{
/* Yes... that that is the one we want. Was it a match with a
* builtin command? Or with an external command.
*/
#ifdef CONFIG_BUILTIN
#ifdef CONFIG_READLINE_HAVE_EXTMATCH
if (nr_builtin_matches == 1)
#endif
{
/* It is a match with a builtin command */
name = builtin_getname(builtin_matches[0]);
}
#endif
#ifdef CONFIG_READLINE_HAVE_EXTMATCH
#ifdef CONFIG_BUILTIN
else
#endif
{
/* It is a match with an external command */
name = g_extmatch_vtbl->getname(ext_matches[0]);
}
#endif
/* Copy the name to the command buffer and to the display. */
name_len = strlen(name);
for (j = len; j < name_len; j++)
{
buf[j] = name[j];
RL_PUTC(vtbl, name[j]);
}
/* Don't remove extra characters after the completed word, if any. */
if (len < name_len)
{
*nch = name_len;
}
}
/* Are there multiple matching names? */
else if (nr_matches > 1)
{
RL_PUTC(vtbl, '\n');
/* See how many characters we can auto complete for the user
* For example, if we have the following commands:
* - prog1
* - prog2
* - prog3
* then it should automatically complete up to prog.
* We do this in one pass using a temp.
*/
memset(tmp_name, 0, sizeof(tmp_name));
#ifdef CONFIG_READLINE_HAVE_EXTMATCH
/* Show the possible external completions */
for (i = 0; i < nr_ext_matches; i++)
{
name = g_extmatch_vtbl->getname(ext_matches[i]);
/* Initialize temp */
if (tmp_name[0] == '\0')
{
strncpy(tmp_name, name, sizeof(tmp_name) - 1);
}
RL_PUTC(vtbl, ' ');
RL_PUTC(vtbl, ' ');
for (j = 0; j < strlen(name); j++)
{
/* Removing characters that aren't common to all the
* matches.
*/
if (name[j] != tmp_name[j])
{
tmp_name[j] = '\0';
}
RL_PUTC(vtbl, name[j]);
}
RL_PUTC(vtbl, '\n');
}
#endif
#ifdef CONFIG_BUILTIN
/* Show the possible builtin completions */
for (i = 0; i < nr_builtin_matches; i++)
{
name = builtin_getname(builtin_matches[i]);
/* Initialize temp */
if (tmp_name[0] == '\0')
{
strncpy(tmp_name, name, sizeof(tmp_name) - 1);
}
RL_PUTC(vtbl, ' ');
RL_PUTC(vtbl, ' ');
for (j = 0; j < strlen(name); j++)
{
/* Removing characters that aren't common to all the
* matches.
*/
if (name[j] != tmp_name[j])
{
tmp_name[j] = '\0';
}
RL_PUTC(vtbl, name[j]);
}
RL_PUTC(vtbl, '\n');
}
#endif
strncpy(buf, tmp_name, buflen - 1);
name_len = strlen(tmp_name);
/* Output the original prompt */
if (g_readline_prompt != NULL)
{
for (i = 0; i < strlen(g_readline_prompt); i++)
{
RL_PUTC(vtbl, g_readline_prompt[i]);
}
}
for (i = 0; i < name_len; i++)
{
RL_PUTC(vtbl, buf[i]);
}
/* Don't remove extra characters after the completed word, if any. */
if (len < name_len)
{
*nch = name_len;
}
}
}
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: readline_prompt
*
* If a prompt string is used by the application, then the application
* must provide the prompt string to readline() by calling this function.
* This is needed only for tab completion in cases where is it necessary
* to reprint the prompt string.
*
* Input Parameters:
* prompt - The prompt string. This function may then be
* called with that value in order to restore the previous vtable.
*
* Returned values:
* Returns the previous value of the prompt string. This function may
* then be called with that value in order to restore the previous prompt.
*
* Assumptions:
* The prompt string is statically allocated a global. readline() will
* simply remember the pointer to the string. The string must stay
* allocated and available. Only one prompt string is supported. If
* there are multiple clients of readline(), they must all share the same
* prompt string (with exceptions in the case of the kernel build).
*
****************************************************************************/
#ifdef CONFIG_READLINE_TABCOMPLETION
FAR const char *readline_prompt(FAR const char *prompt)
{
FAR const char *ret = g_readline_prompt;
g_readline_prompt = prompt;
return ret;
}
#endif
/****************************************************************************
* Name: readline_extmatch
*
* If the applications supports a command set, then it may call this
* function in order to provide support for tab complete on these
* "external" commands
*
* Input Parameters:
* vtbl - Callbacks to access the external names.
*
* Returned values:
* Returns the previous vtable pointer. This function may then be
* called with that value in order to restore the previous vtable.
*
* Assumptions:
* The vtbl string is statically allocated a global. readline() will
* simply remember the pointer to the structure. The structure must stay
* allocated and available. Only one instance of such a structure is
* supported. If there are multiple clients of readline(), they must all
* share the same tab-completion logic (with exceptions in the case of
* the kernel build).
*
****************************************************************************/
#if defined(CONFIG_READLINE_TABCOMPLETION) && defined(CONFIG_READLINE_HAVE_EXTMATCH)
FAR const struct extmatch_vtable_s *
readline_extmatch(FAR const struct extmatch_vtable_s *vtbl)
{
#if (CONFIG_READLINE_MAX_EXTCMDS > 0)
FAR const struct extmatch_vtable_s *ret = g_extmatch_vtbl;
g_extmatch_vtbl = vtbl;
return ret;
#else
return NULL;
#endif
}
#endif
/****************************************************************************
* Name: readline_common
*
* Description:
* readline() reads in at most one less than 'buflen' characters from
* 'instream' and stores them into the buffer pointed to by 'buf'.
* Characters are echoed on 'outstream'. Reading stops after an EOF or a
* newline. If a newline is read, it is stored into the buffer. A null
* terminator is stored after the last character in the buffer.
*
* This version of realine assumes that we are reading and writing to
* a VT100 console. This will not work well if 'instream' or 'outstream'
* corresponds to a raw byte steam.
*
* This function is inspired by the GNU readline but is an entirely
* different creature.
*
* Input Parameters:
* vtbl - vtbl used to access implementation specific interface
* buf - The user allocated buffer to be filled.
* buflen - the size of the buffer.
*
* Returned Value:
* On success, the (positive) number of bytes transferred is returned.
* EOF is returned to indicate either an end of file condition or a
* failure.
*
****************************************************************************/
ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, int buflen)
{
int escape;
int nch;
#ifdef CONFIG_READLINE_CMD_HISTORY
int i;
#endif
/* Sanity checks */
DEBUGASSERT(buf && buflen > 0);
if (buflen < 2)
{
*buf = '\0';
return 0;
}
/* <esc>[K is the VT100 command that erases to the end of the line. */
#ifdef CONFIG_READLINE_ECHO
RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol));
#endif
/* Read characters until we have a full line. On each the loop we must
* be assured that there are two free bytes in the line buffer: One for
* the next character and one for the null terminator.
*/
escape = 0;
nch = 0;
for (;;)
{
/* Get the next character. readline_rawgetc() returns EOF on any
* errors or at the end of file.
*/
int ch = RL_GETC(vtbl);
/* Check for end-of-file or read error */
if (ch == EOF)
{
/* Did we already received some data? */
if (nch > 0)
{
/* Yes.. Terminate the line (which might be zero length)
* and return the data that was received. The end-of-file
* or error condition will be reported next time.
*/
buf[nch] = '\0';
return nch;
}
return EOF;
}
/* Are we processing a VT100 escape sequence */
else if (escape)
{
/* Yes, is it an <esc>[, 3 byte sequence */
if (ch != ASCII_LBRACKET || escape == 2)
{
/* We are finished with the escape sequence */
#ifdef CONFIG_READLINE_CMD_HISTORY
/* Nghia Ho: intercept up and down arrow keys */
if (g_cmd_history_len > 0)
{
if (ch == 'A') /* up arrow */
{
/* Go to the past command in history */
g_cmd_history_steps_from_head--;
if (-g_cmd_history_steps_from_head >= g_cmd_history_len)
{
g_cmd_history_steps_from_head = -(g_cmd_history_len - 1);
}
}
else if (ch == 'B') /* down arrow */
{
/* Go to the recent command in history */
g_cmd_history_steps_from_head++;
if (g_cmd_history_steps_from_head > 1)
{
g_cmd_history_steps_from_head = 1;
}
}
/* Clear out current command from the prompt */
while (nch > 0)
{
nch--;
#ifdef CONFIG_READLINE_ECHO
RL_PUTC(vtbl, ASCII_BS);
RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol));
#endif
}
if (g_cmd_history_steps_from_head != 1)
{
int idx = g_cmd_history_head + g_cmd_history_steps_from_head;
/* Circular buffer wrap around */
if (idx < 0)
{
idx = idx + CONFIG_READLINE_CMD_HISTORY_LEN;
}
else if (idx >= CONFIG_READLINE_CMD_HISTORY_LEN)
{
idx = idx - CONFIG_READLINE_CMD_HISTORY_LEN;
}
for (i = 0; g_cmd_history[idx][i] != '\0'; i++)
{
buf[nch++] = g_cmd_history[idx][i];
RL_PUTC(vtbl, g_cmd_history[idx][i]);
}
}
}
#endif /* CONFIG_READLINE_CMD_HISTORY */
escape = 0;
ch = 'a';
}
else
{
/* The next character is the end of a 3-byte sequence.
* NOTE: Some of the <esc>[ sequences are longer than
* 3-bytes, but I have not encountered any in normal use
* yet and, so, have not provided the decoding logic.
*/
escape = 2;
}
}
/* Check for backspace
*
* There are several notions of backspace, for an elaborate summary see
* http://www.ibb.net/~anne/keyboard.html. There is no clean solution.
* Here both DEL and backspace are treated like backspace here. The
* Unix/Linux screen terminal by default outputs DEL (0x7f) when the
* backspace key is pressed.
*/
else if (ch == ASCII_BS || ch == ASCII_DEL)
{
/* Eliminate that last character in the buffer. */
if (nch > 0)
{
nch--;
#ifdef CONFIG_READLINE_ECHO
/* Echo the backspace character on the console. Always output
* the backspace character because the VT100 terminal doesn't
* understand DEL properly.
*/
RL_PUTC(vtbl, ASCII_BS);
RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol));
#endif
}
}
/* Check for the beginning of a VT100 escape sequence */
else if (ch == ASCII_ESC)
{
/* The next character is escaped */
escape = 1;
}
/* Check for end-of-line. This is tricky only in that some
* environments may return CR as end-of-line, others LF, and
* others both.
*/
#if defined(CONFIG_EOL_IS_LF) || defined(CONFIG_EOL_IS_BOTH_CRLF)
else if (ch == '\n')
#elif defined(CONFIG_EOL_IS_CR)
else if (ch == '\r')
#elif defined(CONFIG_EOL_IS_EITHER_CRLF)
else if (ch == '\n' || ch == '\r')
#endif
{
#ifdef CONFIG_READLINE_CMD_HISTORY
/* Nghia Ho: save history of command, only if there was something
* typed besides return character.
*/
if (nch >= 1)
{
g_cmd_history_head = (g_cmd_history_head + 1) % CONFIG_READLINE_CMD_HISTORY_LEN;
for (i = 0; (i < nch) && i < (CONFIG_READLINE_CMD_HISTORY_LINELEN - 1); i++)
{
g_cmd_history[g_cmd_history_head][i] = buf[i];
}
g_cmd_history[g_cmd_history_head][i] = '\0';
g_cmd_history_steps_from_head = 1;
if (g_cmd_history_len < CONFIG_READLINE_CMD_HISTORY_LEN)
{
g_cmd_history_len++;
}
}
#endif /* CONFIG_READLINE_CMD_HISTORY */
/* The newline is stored in the buffer along with the null
* terminator.
*/
buf[nch++] = '\n';
buf[nch] = '\0';
#ifdef CONFIG_READLINE_ECHO
/* Echo the newline to the console */
RL_PUTC(vtbl, '\n');
#endif
return nch;
}
/* Otherwise, check if the character is printable and, if so, put the
* character in the line buffer
*/
else if (isprint(ch))
{
buf[nch++] = ch;
#ifdef CONFIG_READLINE_ECHO
/* Echo the character to the console */
RL_PUTC(vtbl, ch);
#endif
/* Check if there is room for another character and the line's
* null terminator. If not then we have to end the line now.
*/
if (nch + 1 >= buflen)
{
buf[nch] = '\0';
return nch;
}
}
#ifdef CONFIG_READLINE_TABCOMPLETION
else if (ch == '\t') /* Nghia - TAB character */
{
tab_completion(vtbl, buf, buflen, &nch);
}
#endif
}
}
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