mirror of https://github.com/postgres/postgres
asprintf(), aside from not being particularly portable, has a fundamentally badly-designed API; the psprintf() function that was added in passing in the previous patch has a much better API choice. Moreover, the NetBSD implementation that was borrowed for the previous patch doesn't work with non-C99-compliant vsnprintf, which is something we still have to cope with on some platforms; and it depends on va_copy which isn't all that portable either. Get rid of that code in favor of an implementation similar to what we've used for many years in stringinfo.c. Also, move it into libpgcommon since it's not really libpgport material. I think this patch will be enough to turn the buildfarm green again, but there's still cosmetic work left to do, namely get rid of pg_asprintf() in favor of using psprintf(). That will come in a followon patch.pull/6/head
Tom Lane
12 years ago
parent
586a8fc75b
commit
09a89cb5fc
@ -0,0 +1,207 @@ |
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/*-------------------------------------------------------------------------
|
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* |
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* psprintf.c |
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* sprintf into an allocated-on-demand buffer |
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* |
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* |
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* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group |
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* Portions Copyright (c) 1994, Regents of the University of California |
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* |
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* |
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* IDENTIFICATION |
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* src/common/psprintf.c |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef FRONTEND |
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#include "postgres.h" |
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#else |
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#include "postgres_fe.h" |
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#endif |
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#include "utils/memutils.h" |
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static size_t pvsnprintf(char *buf, size_t len, const char *fmt, va_list args) |
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__attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 0))); |
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|
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/*
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* psprintf |
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* |
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* Format text data under the control of fmt (an sprintf-style format string) |
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* and return it in an allocated-on-demand buffer. The buffer is allocated |
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* with palloc in the backend, or malloc in frontend builds. Caller is |
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* responsible to free the buffer when no longer needed, if appropriate. |
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* |
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* Errors are not returned to the caller, but are reported via elog(ERROR) |
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* in the backend, or printf-to-stderr-and-exit() in frontend builds. |
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* One should therefore think twice about using this in libpq. |
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*/ |
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char * |
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psprintf(const char *fmt,...) |
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{ |
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size_t len = 128; /* initial assumption about buffer size */ |
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for (;;) |
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{ |
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char *result; |
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va_list args; |
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/*
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* Allocate result buffer. Note that in frontend this maps to malloc |
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* with exit-on-error. |
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*/ |
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result = (char *) palloc(len); |
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|
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/* Try to format the data. */ |
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va_start(args, fmt); |
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len = pvsnprintf(result, len, fmt, args); |
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va_end(args); |
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if (len == 0) |
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return result; /* success */ |
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/* Release buffer and loop around to try again with larger len. */ |
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pfree(result); |
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} |
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} |
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|
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/*
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* pvsnprintf |
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* |
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* Attempt to format text data under the control of fmt (an sprintf-style |
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* format string) and insert it into buf (which has length len). |
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* |
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* If successful, return zero. If there's not enough space in buf, return |
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* an estimate of the buffer size needed to succeed (this *must* be more |
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* than "len", else psprintf might loop infinitely). |
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* Other error cases do not return. |
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* |
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* XXX This API is ugly, but there seems no alternative given the C spec's |
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* restrictions on what can portably be done with va_list arguments: you have |
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* to redo va_start before you can rescan the argument list, and we can't do |
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* that from here. |
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*/ |
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static size_t |
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pvsnprintf(char *buf, size_t len, const char *fmt, va_list args) |
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{ |
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int nprinted; |
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Assert(len > 0); |
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errno = 0; |
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/*
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* Assert check here is to catch buggy vsnprintf that overruns the |
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* specified buffer length. Solaris 7 in 64-bit mode is an example of a |
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* platform with such a bug. |
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*/ |
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#ifdef USE_ASSERT_CHECKING |
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buf[len - 1] = '\0'; |
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#endif |
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nprinted = vsnprintf(buf, len, fmt, args); |
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Assert(buf[len - 1] == '\0'); |
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/*
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* If vsnprintf reports an error other than ENOMEM, fail. The possible |
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* causes of this are not user-facing errors, so elog should be enough. |
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*/ |
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if (nprinted < 0 && errno != 0 && errno != ENOMEM) |
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{ |
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#ifndef FRONTEND |
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elog(ERROR, "vsnprintf failed: %m"); |
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#else |
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fprintf(stderr, "vsnprintf failed: %s\n", strerror(errno)); |
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exit(EXIT_FAILURE); |
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#endif |
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} |
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/*
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* Note: some versions of vsnprintf return the number of chars actually |
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* stored, not the total space needed as C99 specifies. And at least one |
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* returns -1 on failure. Be conservative about believing whether the |
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* print worked. |
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*/ |
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if (nprinted >= 0 && (size_t) nprinted < len - 1) |
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{ |
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/* Success. Note nprinted does not include trailing null. */ |
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return 0; |
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} |
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if (nprinted >= 0 && (size_t) nprinted > len) |
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{ |
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/*
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* This appears to be a C99-compliant vsnprintf, so believe its |
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* estimate of the required space. (If it's wrong, this code will |
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* still work, but may loop multiple times.) Note that the space |
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* needed should be only nprinted+1 bytes, but we'd better allocate |
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* one more than that so that the test above will succeed next time. |
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* |
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* In the corner case where the required space just barely overflows, |
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* fall through so that we'll error out below (possibly after looping). |
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*/ |
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if ((size_t) nprinted <= MaxAllocSize - 2) |
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return nprinted + 2; |
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} |
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/*
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* Buffer overrun, and we don't know how much space is needed. Estimate |
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* twice the previous buffer size. If this would overflow, choke. We use |
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* a palloc-oriented overflow limit even when in frontend. |
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*/ |
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if (len > MaxAllocSize / 2) |
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{ |
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#ifndef FRONTEND |
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ereport(ERROR, |
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(errcode(ERRCODE_OUT_OF_MEMORY), |
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errmsg("out of memory"))); |
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#else |
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fprintf(stderr, _("out of memory\n")); |
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exit(EXIT_FAILURE); |
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#endif |
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} |
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return len * 2; |
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} |
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/*
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* XXX this is going away shortly. |
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*/ |
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#ifdef FRONTEND |
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int |
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pg_asprintf(char **ret, const char *fmt, ...) |
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{ |
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size_t len = 128; /* initial assumption about buffer size */ |
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for (;;) |
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{ |
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char *result; |
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va_list args; |
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/*
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* Allocate result buffer. Note that in frontend this maps to malloc |
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* with exit-on-error. |
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*/ |
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result = (char *) palloc(len); |
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/* Try to format the data. */ |
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va_start(args, fmt); |
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len = pvsnprintf(result, len, fmt, args); |
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va_end(args); |
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if (len == 0) |
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{ |
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*ret = result; |
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return 0; |
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} |
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/* Release buffer and loop around to try again with larger len. */ |
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pfree(result); |
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} |
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} |
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#endif |
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@ -1,111 +0,0 @@ |
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/* src/port/asprintf.c */ |
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/* $NetBSD: asprintf.c,v 1.3 2012/07/02 16:02:53 joerg Exp $ */ |
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/*-
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* Copyright (c) 2007 Joerg Sonnenberger <joerg@NetBSD.org>. |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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#include "c.h" |
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#define HAVE_VA_COPY 1 |
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int |
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asprintf(char **ret, const char *fmt, ...) |
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{ |
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va_list ap; |
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int retval; |
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va_start(ap, fmt); |
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retval = vasprintf(ret, fmt, ap); |
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va_end(ap); |
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return retval; |
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} |
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int |
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vasprintf(char **ret, const char *fmt, va_list ap) |
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{ |
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char *buf, *new_buf; |
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size_t len; |
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int retval; |
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va_list ap2; |
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len = 128; |
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buf = malloc(len); |
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if (buf == NULL) { |
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*ret = NULL; |
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return -1; |
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} |
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#if defined(HAVE_VA_COPY) |
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va_copy(ap2, ap); |
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#define my_va_end(ap2) va_end(ap2) |
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#elif defined(HAVE___BUILTIN_VA_COPY) |
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__builtin_va_copy(ap2, ap); |
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#define my_va_end(ap2) __builtin_va_end(ap2) |
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#else |
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ap2 = ap; |
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#define my_va_end(ap2) do {} while (0) |
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#endif |
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retval = vsnprintf(buf, len, fmt, ap); |
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if (retval < 0) { |
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free(buf); |
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*ret = NULL; |
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va_end(ap2); |
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return -1; |
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} |
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if (retval < len) { |
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new_buf = realloc(buf, retval + 1); |
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if (new_buf == NULL) |
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*ret = buf; |
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else |
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*ret = new_buf; |
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my_va_end(ap2); |
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return retval; |
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} |
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len = (size_t)retval + 1; |
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free(buf); |
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buf = malloc(len); |
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if (buf == NULL) { |
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*ret = NULL; |
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my_va_end(ap2); |
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return -1; |
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} |
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retval = vsnprintf(buf, len, fmt, ap2); |
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my_va_end(ap2); |
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if (retval != len - 1) { |
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free(buf); |
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*ret = NULL; |
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return -1; |
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} |
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*ret = buf; |
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return retval; |
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} |
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Loading…
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