339 lines
8.1 KiB
C++
339 lines
8.1 KiB
C++
/*
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* Copyright (c) 2016 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2020-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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#include "maxscale/externcmd.h"
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#include <ctype.h>
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#include <errno.h>
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#include <string.h>
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#include <maxscale/alloc.h>
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#include <maxscale/log_manager.h>
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#include <maxscale/pcre2.h>
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/**
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* Tokenize a string into arguments suitable for a execvp call.
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* @param args Argument string
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* @param argv Array of char pointers to be filled with tokenized arguments
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* @return 0 on success, -1 on error
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*/
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int tokenize_arguments(char* argstr, char** argv)
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{
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int i = 0;
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bool quoted = false;
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bool read = false;
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bool escaped = false;
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char *ptr, *start;
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char args[strlen(argstr) + 1];
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char qc = 0;
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strcpy(args, argstr);
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start = args;
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ptr = start;
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while (*ptr != '\0' && i < MAXSCALE_EXTCMD_ARG_MAX)
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{
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if (escaped)
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{
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escaped = false;
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}
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else
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{
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if (*ptr == '\\')
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{
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escaped = true;
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}
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else if (quoted && !escaped && *ptr == qc) /** End of quoted string */
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{
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*ptr = '\0';
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argv[i++] = MXS_STRDUP_A(start);
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read = false;
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quoted = false;
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}
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else if (!quoted)
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{
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if (isspace(*ptr))
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{
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*ptr = '\0';
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if (read) /** New token */
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{
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argv[i++] = MXS_STRDUP_A(start);
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read = false;
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}
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}
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else if (*ptr == '\"' || *ptr == '\'')
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{
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/** New quoted token, strip quotes */
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quoted = true;
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qc = *ptr;
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start = ptr + 1;
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}
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else if (!read)
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{
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start = ptr;
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read = true;
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}
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}
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}
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ptr++;
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}
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if (read)
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{
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argv[i++] = MXS_STRDUP_A(start);
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}
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argv[i] = NULL;
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return 0;
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}
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/**
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* Allocate a new external command.
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* The name and parameters are copied into the external command structure so
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* the original memory can be freed if needed.
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* @param command Command to execute with the parameters
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* @return Pointer to new external command struct or NULL if an error occurred
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*/
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EXTERNCMD* externcmd_allocate(char* argstr)
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{
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EXTERNCMD* cmd = (EXTERNCMD*) MXS_MALLOC(sizeof(EXTERNCMD));
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char** argv = (char**) MXS_MALLOC(sizeof(char*) * MAXSCALE_EXTCMD_ARG_MAX);
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if (argstr && cmd && argv)
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{
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cmd->argv = argv;
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if (tokenize_arguments(argstr, cmd->argv) == 0)
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{
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if (access(cmd->argv[0], X_OK) != 0)
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{
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if (access(cmd->argv[0], F_OK) != 0)
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{
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MXS_ERROR("Cannot find file: %s", cmd->argv[0]);
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}
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else
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{
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MXS_ERROR("Cannot execute file '%s'. Missing "
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"execution permissions.", cmd->argv[0]);
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}
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externcmd_free(cmd);
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cmd = NULL;
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}
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}
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else
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{
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MXS_ERROR("Failed to parse argument string for external command: %s",
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argstr);
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externcmd_free(cmd);
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cmd = NULL;
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}
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}
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else
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{
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MXS_FREE(cmd);
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MXS_FREE(argv);
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cmd = NULL;
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}
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return cmd;
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}
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/**
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* Free a previously allocated external command.
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* @param cmd Command to free
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*/
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void externcmd_free(EXTERNCMD* cmd)
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{
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if (cmd)
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{
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for (int i = 0; cmd->argv[i]; i++)
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{
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MXS_FREE(cmd->argv[i]);
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}
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MXS_FREE(cmd->argv);
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MXS_FREE(cmd);
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}
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}
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/**
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*Execute a command in a separate process.
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*@param cmd Command to execute
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*@return 0 on success, -1 on error.
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*/
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int externcmd_execute(EXTERNCMD* cmd)
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{
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int rval = 0;
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pid_t pid;
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pid = fork();
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if (pid < 0)
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{
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MXS_ERROR("Failed to execute command '%s', fork failed: [%d] %s",
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cmd->argv[0], errno, mxs_strerror(errno));
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rval = -1;
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}
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else if (pid == 0)
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{
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/** Child process, execute command */
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execvp(cmd->argv[0], cmd->argv);
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_exit(1);
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}
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else
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{
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cmd->child = pid;
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cmd->n_exec++;
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MXS_DEBUG("[monitor_exec_cmd] Forked child process %d : %s.", pid, cmd->argv[0]);
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}
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return rval;
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}
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/**
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* Substitute all occurrences of @c match with @c replace in the arguments for @c cmd.
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* @param cmd External command
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* @param match Match string
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* @param replace Replacement string
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* @return true if replacement was successful, false on error
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*/
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bool externcmd_substitute_arg(EXTERNCMD* cmd, const char* match, const char* replace)
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{
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int err;
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bool rval = true;
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size_t errpos;
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pcre2_code *re = pcre2_compile((PCRE2_SPTR) match, PCRE2_ZERO_TERMINATED, 0, &err, &errpos, NULL);
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if (re)
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{
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for (int i = 0; cmd->argv[i] && rval; i++)
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{
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size_t size = strlen(cmd->argv[i]);
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char* dest = (char*)MXS_MALLOC(size);
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if (dest)
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{
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mxs_pcre2_result_t rc = mxs_pcre2_substitute(re, cmd->argv[i], replace, &dest, &size);
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switch (rc)
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{
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case MXS_PCRE2_ERROR:
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MXS_FREE(dest);
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rval = false;
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break;
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case MXS_PCRE2_MATCH:
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MXS_FREE(cmd->argv[i]);
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cmd->argv[i] = dest;
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break;
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case MXS_PCRE2_NOMATCH:
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MXS_FREE(dest);
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break;
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}
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}
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}
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pcre2_code_free(re);
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}
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else
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{
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rval = false;
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}
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return rval;
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}
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/**
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* Get the name of the command being executed.
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*
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* This copies the command being executed into a new string.
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* @param str Command string, optionally with arguments
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* @return Command part of the string if arguments were defined
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*/
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char* get_command(const char* str)
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{
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char* rval = NULL;
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const char* start = str;
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while (*start && isspace(*start))
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{
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start++;
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}
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const char* end = start;
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while (*end && !isspace(*end))
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{
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end++;
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}
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size_t len = end - start;
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if (len > 0)
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{
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rval = (char*)MXS_MALLOC(len + 1);
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if (rval)
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{
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memcpy(rval, start, len);
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rval[len] = '\0';
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}
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}
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return rval;
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}
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/**
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* Check if a command can be executed.
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*
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* Checks if the file being executed exists and if the current user has execution
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* permissions on the file.
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* @param argstr Command to check. Can contain arguments for the command.
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* @return True if the file was found and the use has execution permissions to it.
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*/
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bool externcmd_can_execute(const char* argstr)
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{
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bool rval = false;
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char *command = get_command(argstr);
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if (command)
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{
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if (access(command, X_OK) == 0)
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{
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rval = true;
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}
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else if (access(command, F_OK) == 0)
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{
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MXS_ERROR("The executable cannot be executed: %s", command);
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}
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else
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{
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MXS_ERROR("The executable cannot be found: %s", command);
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}
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MXS_FREE(command);
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}
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return rval;
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}
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/**
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* Simple matching of string and command
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* @param cmd Command where the match is searched from
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* @param match String to search for
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* @return True if the string matched
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*/
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bool externcmd_matches(const EXTERNCMD* cmd, const char* match)
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{
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for (int i = 0; cmd->argv[i]; i++)
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{
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if (strstr(cmd->argv[i], match))
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{
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return true;
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}
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}
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return false;
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}
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