diff options
Diffstat (limited to 'contrib/pg_upgrade/util.c')
| -rw-r--r-- | contrib/pg_upgrade/util.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/contrib/pg_upgrade/util.c b/contrib/pg_upgrade/util.c index c32cfcae645..264357c1d77 100644 --- a/contrib/pg_upgrade/util.c +++ b/contrib/pg_upgrade/util.c @@ -152,6 +152,210 @@ quote_identifier(const char *s) /* + * Append the given string to the shell command being built in the buffer, + * with suitable shell-style quoting to create exactly one argument. + * + * Forbid LF or CR characters, which have scant practical use beyond designing + * security breaches. The Windows command shell is unusable as a conduit for + * arguments containing LF or CR characters. A future major release should + * reject those characters in CREATE ROLE and CREATE DATABASE, because use + * there eventually leads to errors here. + */ +void +appendShellString(PQExpBuffer buf, const char *str) +{ + const char *p; + +#ifndef WIN32 + appendPQExpBufferChar(buf, '\''); + for (p = str; *p; p++) + { + if (*p == '\n' || *p == '\r') + { + fprintf(stderr, + _("shell command argument contains a newline or carriage return: \"%s\"\n"), + str); + exit(EXIT_FAILURE); + } + + if (*p == '\'') + appendPQExpBufferStr(buf, "'\"'\"'"); + else + appendPQExpBufferChar(buf, *p); + } + appendPQExpBufferChar(buf, '\''); +#else /* WIN32 */ + int backslash_run_length = 0; + + /* + * A Windows system() argument experiences two layers of interpretation. + * First, cmd.exe interprets the string. Its behavior is undocumented, + * but a caret escapes any byte except LF or CR that would otherwise have + * special meaning. Handling of a caret before LF or CR differs between + * "cmd.exe /c" and other modes, and it is unusable here. + * + * Second, the new process parses its command line to construct argv (see + * https://msdn.microsoft.com/en-us/library/17w5ykft.aspx). This treats + * backslash-double quote sequences specially. + */ + appendPQExpBufferStr(buf, "^\""); + for (p = str; *p; p++) + { + if (*p == '\n' || *p == '\r') + { + fprintf(stderr, + _("shell command argument contains a newline or carriage return: \"%s\"\n"), + str); + exit(EXIT_FAILURE); + } + + /* Change N backslashes before a double quote to 2N+1 backslashes. */ + if (*p == '"') + { + while (backslash_run_length) + { + appendPQExpBufferStr(buf, "^\\"); + backslash_run_length--; + } + appendPQExpBufferStr(buf, "^\\"); + } + else if (*p == '\\') + backslash_run_length++; + else + backslash_run_length = 0; + + /* + * Decline to caret-escape the most mundane characters, to ease + * debugging and lest we approach the command length limit. + */ + if (!((*p >= 'a' && *p <= 'z') || + (*p >= 'A' && *p <= 'Z') || + (*p >= '0' && *p <= '9'))) + appendPQExpBufferChar(buf, '^'); + appendPQExpBufferChar(buf, *p); + } + + /* + * Change N backslashes at end of argument to 2N backslashes, because they + * precede the double quote that terminates the argument. + */ + while (backslash_run_length) + { + appendPQExpBufferStr(buf, "^\\"); + backslash_run_length--; + } + appendPQExpBufferStr(buf, "^\""); +#endif /* WIN32 */ +} + + +/* + * Append the given string to the buffer, with suitable quoting for passing + * the string as a value, in a keyword/pair value in a libpq connection + * string + */ +void +appendConnStrVal(PQExpBuffer buf, const char *str) +{ + const char *s; + bool needquotes; + + /* + * If the string is one or more plain ASCII characters, no need to quote + * it. This is quite conservative, but better safe than sorry. + */ + needquotes = true; + for (s = str; *s; s++) + { + if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') || + (*s >= '0' && *s <= '9') || *s == '_' || *s == '.')) + { + needquotes = true; + break; + } + needquotes = false; + } + + if (needquotes) + { + appendPQExpBufferChar(buf, '\''); + while (*str) + { + /* ' and \ must be escaped by to \' and \\ */ + if (*str == '\'' || *str == '\\') + appendPQExpBufferChar(buf, '\\'); + + appendPQExpBufferChar(buf, *str); + str++; + } + appendPQExpBufferChar(buf, '\''); + } + else + appendPQExpBufferStr(buf, str); +} + + +/* + * Append a psql meta-command that connects to the given database with the + * then-current connection's user, host and port. + */ +void +appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname) +{ + const char *s; + bool complex; + + /* + * If the name is plain ASCII characters, emit a trivial "\connect "foo"". + * For other names, even many not technically requiring it, skip to the + * general case. No database has a zero-length name. + */ + complex = false; + for (s = dbname; *s; s++) + { + if (*s == '\n' || *s == '\r') + { + fprintf(stderr, + _("database name contains a newline or carriage return: \"%s\"\n"), + dbname); + exit(EXIT_FAILURE); + } + + if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') || + (*s >= '0' && *s <= '9') || *s == '_' || *s == '.')) + { + complex = true; + } + } + + appendPQExpBufferStr(buf, "\\connect "); + if (complex) + { + PQExpBufferData connstr; + + initPQExpBuffer(&connstr); + appendPQExpBuffer(&connstr, "dbname="); + appendConnStrVal(&connstr, dbname); + + appendPQExpBuffer(buf, "-reuse-previous=on "); + + /* + * As long as the name does not contain a newline, SQL identifier + * quoting satisfies the psql meta-command parser. Prefer not to + * involve psql-interpreted single quotes, which behaved differently + * before PostgreSQL 9.2. + */ + appendPQExpBufferStr(buf, quote_identifier(connstr.data)); + + termPQExpBuffer(&connstr); + } + else + appendPQExpBufferStr(buf, quote_identifier(dbname)); + appendPQExpBufferChar(buf, '\n'); +} + + +/* * get_user_info() * (copied from initdb.c) find the current user */ |