184 lines
6.2 KiB
Diff
184 lines
6.2 KiB
Diff
From 8cfb43de636faa401634340d1a18404844f9ba5a Mon Sep 17 00:00:00 2001
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From: Mike Frysinger <vapier@gentoo.org>
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Date: Sun, 6 May 2012 03:50:44 -0400
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Subject: [PATCH] stdio: implement assignment-allocation "m" character
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The latest POSIX spec introduces a "m" character to allocate buffers for
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the user when using scanf type functions. This is like the old glibc "a"
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flag, but now standardized. With packages starting to use these, we need
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to implement it.
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for example:
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char *s;
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sscanf("foo", "%ms", &s);
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printf("%s\n", s);
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free(s);
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This will automatically allocate storage for "s", read in "foo" to it,
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and then display it.
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I'm not terribly familiar with the stdio layer, so this could be wrong.
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But it seems to work for me.
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Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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Signed-off-by: Felix Fietkau <nbd@openwrt.org>
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---
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extra/Configs/Config.in | 13 ----------
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libc/stdio/_scanf.c | 68 ++++++++++++++++++++++++++++---------------------
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2 files changed, 39 insertions(+), 42 deletions(-)
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--- a/extra/Configs/Config.in
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+++ b/extra/Configs/Config.in
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@@ -1590,19 +1590,6 @@ config UCLIBC_PRINTF_SCANF_POSITIONAL_AR
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Most people will answer 9.
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-
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-config UCLIBC_HAS_SCANF_GLIBC_A_FLAG
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- bool "Support glibc's 'a' flag for scanf string conversions (not implemented)"
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- help
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- NOTE!!! Currently Not Implemented!!! Just A Place Holder!! NOTE!!!
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- NOTE!!! Conflicts with an ANSI/ISO C99 scanf flag!! NOTE!!!
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-
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- Answer Y to enable support for glibc's 'a' flag for the scanf string
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- conversions '%s', '%[', '%ls', '%l[', and '%S'. This is used to
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- auto-allocate sufficient memory to hold the data retrieved.
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-
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- Most people will answer N.
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-
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choice
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prompt "Stdio buffer size"
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default UCLIBC_HAS_STDIO_BUFSIZ_4096
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--- a/libc/stdio/_scanf.c
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+++ b/libc/stdio/_scanf.c
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@@ -77,14 +77,6 @@
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#include <bits/uClibc_fpmax.h>
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#endif /* __UCLIBC_HAS_FLOATS__ */
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-#ifdef __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__
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-#ifdef L_vfscanf
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-/* only emit this once */
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-#warning Forcing undef of __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__ until implemented!
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-#endif
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-#undef __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__
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-#endif
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-
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#undef __STDIO_HAS_VSSCANF
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#if defined(__STDIO_BUFFERS) || !defined(__UCLIBC_HAS_WCHAR__) || defined(__UCLIBC_HAS_GLIBC_CUSTOM_STREAMS__)
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#define __STDIO_HAS_VSSCANF 1
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@@ -433,8 +425,9 @@ libc_hidden_def(vswscanf)
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/* float layout 0123456789012345678901 repeat n for "l[" */
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-#define SPEC_CHARS "npxXoudifFeEgGaACSncs["
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-/* npxXoudif eEgG CS cs[ */
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+#define SPEC_CHARS "npxXoudifFeEgGaACSnmcs["
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+/* npxXoudif eEgG CS cs[ */
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+/* NOTE: the 'm' flag must come before any convs that support it */
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/* NOTE: Ordering is important! In particular, CONV_LEFTBRACKET
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* must immediately precede CONV_c. */
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@@ -444,7 +437,7 @@ enum {
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CONV_p,
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CONV_x, CONV_X, CONV_o, CONV_u, CONV_d, CONV_i,
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CONV_f, CONV_F, CONV_e, CONV_E, CONV_g, CONV_G, CONV_a, CONV_A,
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- CONV_C, CONV_S, CONV_LEFTBRACKET, CONV_c, CONV_s, CONV_leftbracket,
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+ CONV_C, CONV_S, CONV_LEFTBRACKET, CONV_m, CONV_c, CONV_s, CONV_leftbracket,
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CONV_percent, CONV_whitespace /* not in SPEC_* and no flags */
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};
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@@ -474,7 +467,7 @@ enum {
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FLAG_SURPRESS = 0x10, /* MUST BE 1ST!! See DO_FLAGS. */
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FLAG_THOUSANDS = 0x20,
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FLAG_I18N = 0x40, /* only works for d, i, u */
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- FLAG_MALLOC = 0x80, /* only works for s, S, and [ (and l[)*/
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+ FLAG_MALLOC = 0x80, /* only works for c, s, S, and [ (and l[)*/
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};
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@@ -491,7 +484,7 @@ enum {
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/* fFeEgGaA */ (0x0c|FLAG_SURPRESS|FLAG_THOUSANDS|FLAG_I18N), \
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/* C */ ( 0|FLAG_SURPRESS), \
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/* S and l[ */ ( 0|FLAG_SURPRESS|FLAG_MALLOC), \
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- /* c */ (0x04|FLAG_SURPRESS), \
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+ /* c */ (0x04|FLAG_SURPRESS|FLAG_MALLOC), \
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/* s and [ */ (0x04|FLAG_SURPRESS|FLAG_MALLOC), \
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}
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@@ -904,17 +897,17 @@ int attribute_hidden __psfs_parse_spec(r
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if (*psfs->fmt == *p) {
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int p_m_spec_chars = p - spec_chars;
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-#ifdef __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__
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-#error implement gnu a flag
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- if ((*p == 'a')
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- && ((psfs->fmt[1] == '[') || ((psfs->fmt[1]|0x20) == 's'))
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- ) { /* Assumes ascii for 's' and 'S' test. */
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- psfs->flags |= FLAG_MALLOC;
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+ if (*p == 'm' &&
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+ (psfs->fmt[1] == '[' || psfs->fmt[1] == 'c' ||
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+ /* Assumes ascii for 's' and 'S' test. */
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+ (psfs->fmt[1] | 0x20) == 's'))
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+ {
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+ if (psfs->store)
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+ psfs->flags |= FLAG_MALLOC;
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++psfs->fmt;
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++p;
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- continue; /* The related conversions follow 'a'. */
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+ continue; /* The related conversions follow 'm'. */
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}
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-#endif /* __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__ */
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for (p = spec_ranges; p_m_spec_chars > *p ; ++p) {}
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if (((psfs->dataargtype >> 8) | psfs->flags)
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@@ -1265,12 +1258,6 @@ int VFSCANF (FILE *__restrict fp, const
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while (*wf && __isascii(*wf) && (b < buf + sizeof(buf) - 1)) {
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*b++ = *wf++;
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}
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-#ifdef __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__
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-#error this is wrong... we need to ched in __psfs_parse_spec instead since this checks last char in buffer and conversion my have stopped before it.
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- if ((*b == 'a') && ((*wf == '[') || ((*wf|0x20) == 's'))) {
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- goto DONE; /* Spec was excessively long. */
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- }
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-#endif /* __UCLIBC_HAS_SCANF_GLIBC_A_FLAG__ */
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*b = 0;
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if (b == buf) { /* Bad conversion specifier! */
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goto DONE;
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@@ -1390,13 +1377,36 @@ int VFSCANF (FILE *__restrict fp, const
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}
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if (psfs.conv_num == CONV_s) {
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+ /* We might have to handle the allocation ourselves */
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+ int len;
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+ /* With 'm', we actually got a pointer to a pointer */
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+ unsigned char **ptr = (void *)b;
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+
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+ i = 0;
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+ if (psfs.flags & FLAG_MALLOC) {
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+ len = 0;
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+ b = NULL;
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+ } else
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+ len = -1;
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+
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/* Yes, believe it or not, a %s conversion can store nuls. */
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while ((__scan_getc(&sc) >= 0) && !isspace(sc.cc)) {
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zero_conversions = 0;
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- *b = sc.cc;
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- b += psfs.store;
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+ if (i == len) {
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+ /* Pick a size that won't trigger a lot of
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+ * mallocs early on ... */
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+ len += 256;
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+ b = realloc(b, len + 1);
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+ }
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+ b[i] = sc.cc;
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+ i += psfs.store;
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fail = 0;
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}
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+
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+ if (psfs.flags & FLAG_MALLOC)
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+ *ptr = b;
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+ /* The code below takes care of terminating NUL */
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+ b += i;
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} else {
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#ifdef __UCLIBC_HAS_WCHAR__
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assert((psfs.conv_num == CONV_LEFTBRACKET) || \
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