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Catch fatal flex errors in the GUC file lexer.

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This prevents the postmaster from unexpectedly croaking if postgresql.conf
contains something like:

include 'invalid_directory_name'

Noah Misch. Reviewed by Tom Lane and myself.
This commit is contained in:
Robert Haas 2012-01-17 20:51:38 -05:00
parent 754b8140a1
commit 4b496a3583
1 changed files with 53 additions and 12 deletions
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65
src/backend/utils/misc/guc-file.l
View File

@ -20,9 +20,14 @@
#include "utils/guc.h"
/* Avoid exit() on fatal scanner errors (a bit ugly -- see yy_fatal_error) */
/*
* flex emits a yy_fatal_error() function that it calls in response to
* critical errors like malloc failure, file I/O errors, and detection of
* internal inconsistency. That function prints a message and calls exit().
* Mutate it to instead call our handler, which jumps out of the parser.
*/
#undef fprintf
#define fprintf(file, fmt, msg) ereport(ERROR, (errmsg_internal("%s", msg)))
#define fprintf(file, fmt, msg) GUC_flex_fatal(msg)
enum {
GUC_ID = 1,
@ -37,10 +42,13 @@ enum {
};
static unsigned int ConfigFileLineno;
static const char *GUC_flex_fatal_errmsg;
static sigjmp_buf *GUC_flex_fatal_jmp;
/* flex fails to supply a prototype for yylex, so provide one */
int GUC_yylex(void);
static int GUC_flex_fatal(const char *msg);
static char *GUC_scanstr(const char *s);
%}
@ -436,6 +444,22 @@ ParseConfigFile(const char *config_file, const char *calling_file, bool strict,
return OK;
}
/*
* Flex fatal errors bring us here. Stash the error message and jump back to
* ParseConfigFp(). Assume all msg arguments point to string constants; this
* holds for flex 2.5.31 (earliest we support) and flex 2.5.35 (latest as of
* this writing). Otherwise, we would need to copy the message.
*
* We return "int" since this takes the place of calls to fprintf().
*/
static int
GUC_flex_fatal(const char *msg)
{
GUC_flex_fatal_errmsg = msg;
siglongjmp(*GUC_flex_fatal_jmp, 1);
return 0; /* keep compiler quiet */
}
/*
* Read and parse a single configuration file. This function recurses
* to handle "include" directives.
@ -464,19 +488,38 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
ConfigVariable **head_p, ConfigVariable **tail_p)
{
bool OK = true;
YY_BUFFER_STATE lex_buffer;
unsigned int save_ConfigFileLineno = ConfigFileLineno;
sigjmp_buf *save_GUC_flex_fatal_jmp = GUC_flex_fatal_jmp;
sigjmp_buf flex_fatal_jmp;
volatile YY_BUFFER_STATE lex_buffer = NULL;
int errorcount;
int token;
if (sigsetjmp(flex_fatal_jmp, 1) == 0)
GUC_flex_fatal_jmp = &flex_fatal_jmp;
else
{
/*
* Regain control after a fatal, internal flex error. It may have
* corrupted parser state. Consequently, abandon the file, but trust
* that the state remains sane enough for yy_delete_buffer().
*/
elog(elevel, "%s at file \"%s\" line %u",
GUC_flex_fatal_errmsg, config_file, ConfigFileLineno);
OK = false;
goto cleanup;
}
/*
* Parse
*/
lex_buffer = yy_create_buffer(fp, YY_BUF_SIZE);
yy_switch_to_buffer(lex_buffer);
ConfigFileLineno = 1;
errorcount = 0;
lex_buffer = yy_create_buffer(fp, YY_BUF_SIZE);
yy_switch_to_buffer(lex_buffer);
/* This loop iterates once per logical line */
while ((token = yylex()))
{
@ -526,14 +569,11 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
* An include_if_exists directive isn't a variable and should be
* processed immediately.
*/
unsigned int save_ConfigFileLineno = ConfigFileLineno;
if (!ParseConfigFile(opt_value, config_file, false,
depth + 1, elevel,
head_p, tail_p))
OK = false;
yy_switch_to_buffer(lex_buffer);
ConfigFileLineno = save_ConfigFileLineno;
pfree(opt_name);
pfree(opt_value);
}
@ -543,14 +583,11 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
* An include directive isn't a variable and should be processed
* immediately.
*/
unsigned int save_ConfigFileLineno = ConfigFileLineno;
if (!ParseConfigFile(opt_value, config_file, true,
depth + 1, elevel,
head_p, tail_p))
OK = false;
yy_switch_to_buffer(lex_buffer);
ConfigFileLineno = save_ConfigFileLineno;
pfree(opt_name);
pfree(opt_value);
}
@ -620,7 +657,11 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
break;
}
cleanup:
yy_delete_buffer(lex_buffer);
/* Each recursion level must save and restore these static variables. */
ConfigFileLineno = save_ConfigFileLineno;
GUC_flex_fatal_jmp = save_GUC_flex_fatal_jmp;
return OK;
}