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authorDenis Vlasenko <vda.linux@googlemail.com>2007-11-22 08:16:57 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2007-11-22 08:16:57 +0000
commit7d75a96b15327050a294b1f54981781ce6e551e2 (patch)
treedf8a1fcb74b6bd7869fe60af461c11f0684df043 /coreutils/echo.c
parent705eaf8b403555741cf6313a76da8597ae54d324 (diff)
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ash: fix bug where redirection of closed fd was leaving it open afterwards.
redirect 983 1024 +41 bb_echo 276 301 +25 popredir 118 132 +14 evalcommand 1163 1176 +13 bbunpack 358 366 +8 echocmd 13 5 -8 echo_main 13 5 -8 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 5/2 up/down: 101/-16) Total: 85 bytes text data bss dec hex filename 774999 962 9236 785197 bfb2d busybox_old 775084 962 9236 785282 bfb82 busybox_unstripped
Diffstat (limited to 'coreutils/echo.c')
-rw-r--r--coreutils/echo.c141
1 files changed, 139 insertions, 2 deletions
diff --git a/coreutils/echo.c b/coreutils/echo.c
index 860853f02..4c7a91743 100644
--- a/coreutils/echo.c
+++ b/coreutils/echo.c
@@ -25,7 +25,9 @@
25 25
26#include "libbb.h" 26#include "libbb.h"
27 27
28int bb_echo(char **argv) 28/* argc is unused, but removing it precludes compiler from
29 * using call -> jump optimization */
30int bb_echo(int argc, char **argv)
29{ 31{
30 const char *arg; 32 const char *arg;
31#if !ENABLE_FEATURE_FANCY_ECHO 33#if !ENABLE_FEATURE_FANCY_ECHO
@@ -33,6 +35,18 @@ int bb_echo(char **argv)
33 eflag = '\\', 35 eflag = '\\',
34 nflag = 1, /* 1 -- print '\n' */ 36 nflag = 1, /* 1 -- print '\n' */
35 }; 37 };
38
39 /* We must check that stdout is not closed.
40 * The reason for this is highly non-obvious.
41 * bb_echo is used from shell. Shell must correctly handle "echo foo"
42 * if stdout is closed. With stdio, output gets shoveled into
43 * stdout buffer, and even fflush cannot clear it out. It seems that
44 * even if libc receives EBADF on write attempts, it feels determined
45 * to output data no matter what. So it will try later,
46 * and possibly will clobber future output. Not good. */
47 if (dup2(1, 1) != 1)
48 return -1;
49
36 arg = *++argv; 50 arg = *++argv;
37 if (!arg) 51 if (!arg)
38 goto newline_ret; 52 goto newline_ret;
@@ -41,6 +55,10 @@ int bb_echo(char **argv)
41 char nflag = 1; 55 char nflag = 1;
42 char eflag = 0; 56 char eflag = 0;
43 57
58 /* We must check that stdout is not closed. */
59 if (dup2(1, 1) != 1)
60 return -1;
61
44 while (1) { 62 while (1) {
45 arg = *++argv; 63 arg = *++argv;
46 if (!arg) 64 if (!arg)
@@ -122,7 +140,7 @@ int bb_echo(char **argv)
122int echo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 140int echo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
123int echo_main(int argc, char **argv) 141int echo_main(int argc, char **argv)
124{ 142{
125 return bb_echo(argv); 143 return bb_echo(argc, argv);
126} 144}
127 145
128/*- 146/*-
@@ -163,3 +181,122 @@ int echo_main(int argc, char **argv)
163 * 181 *
164 * @(#)echo.c 8.1 (Berkeley) 5/31/93 182 * @(#)echo.c 8.1 (Berkeley) 5/31/93
165 */ 183 */
184
185#ifdef VERSION_WITH_WRITEV
186/* We can't use stdio.
187 * The reason for this is highly non-obvious.
188 * bb_echo is used from shell. Shell must correctly handle "echo foo"
189 * if stdout is closed. With stdio, output gets shoveled into
190 * stdout buffer, and even fflush cannot clear it out. It seems that
191 * even if libc receives EBADF on write attempts, it feels determined
192 * to output data no matter what. So it will try later,
193 * and possibly will clobber future output. Not good.
194 *
195 * Using writev instead, with 'direct' conversion of argv vector.
196 */
197
198int bb_echo(int argc, char **argv)
199{
200 struct iovec io[argc];
201 struct iovec *cur_io = io;
202 char *arg;
203 char *p;
204#if !ENABLE_FEATURE_FANCY_ECHO
205 enum {
206 eflag = '\\',
207 nflag = 1, /* 1 -- print '\n' */
208 };
209 arg = *++argv;
210 if (!arg)
211 goto newline_ret;
212#else
213 char nflag = 1;
214 char eflag = 0;
215
216 while (1) {
217 arg = *++argv;
218 if (!arg)
219 goto newline_ret;
220 if (*arg != '-')
221 break;
222
223 /* If it appears that we are handling options, then make sure
224 * that all of the options specified are actually valid.
225 * Otherwise, the string should just be echoed.
226 */
227 p = arg + 1;
228 if (!*p) /* A single '-', so echo it. */
229 goto just_echo;
230
231 do {
232 if (!strrchr("neE", *p))
233 goto just_echo;
234 } while (*++p);
235
236 /* All of the options in this arg are valid, so handle them. */
237 p = arg + 1;
238 do {
239 if (*p == 'n')
240 nflag = 0;
241 if (*p == 'e')
242 eflag = '\\';
243 } while (*++p);
244 }
245 just_echo:
246#endif
247
248 while (1) {
249 /* arg is already == *argv and isn't NULL */
250 int c;
251
252 cur_io->iov_base = p = arg;
253
254 if (!eflag) {
255 /* optimization for very common case */
256 p += strlen(arg);
257 } else while ((c = *arg++)) {
258 if (c == eflag) { /* Check for escape seq. */
259 if (*arg == 'c') {
260 /* '\c' means cancel newline and
261 * ignore all subsequent chars. */
262 cur_io->iov_len = p - (char*)cur_io->iov_base;
263 cur_io++;
264 goto ret;
265 }
266#if !ENABLE_FEATURE_FANCY_ECHO
267 /* SUSv3 specifies that octal escapes must begin with '0'. */
268 if ( (((unsigned char)*arg) - '1') >= 7)
269#endif
270 {
271 /* Since SUSv3 mandates a first digit of 0, 4-digit octals
272 * of the form \0### are accepted. */
273 if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
274 arg++;
275 }
276 /* bb_process_escape_sequence can handle nul correctly */
277 c = bb_process_escape_sequence( (void*) &arg);
278 }
279 }
280 *p++ = c;
281 }
282
283 arg = *++argv;
284 if (arg)
285 *p++ = ' ';
286 cur_io->iov_len = p - (char*)cur_io->iov_base;
287 cur_io++;
288 if (!arg)
289 break;
290 }
291
292 newline_ret:
293 if (nflag) {
294 cur_io->iov_base = (char*)"\n";
295 cur_io->iov_len = 1;
296 cur_io++;
297 }
298 ret:
299 /* TODO: implement and use full_writev? */
300 return writev(1, io, (cur_io - io)) >= 0;
301}
302#endif