echo: fix ENOSPC detection and some iffy code in \NNN handling

function                                             old     new   delta
echo_main                                            330     302     -28

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/coreutils/echo.c b/coreutils/echo.c
index 5fa3d10c55e64aafa7c3caf456343b04512a1eb8..42c3f9ed864d04e3788c58004f97c4d7d084fe27 100644 (file)
--- a/coreutils/echo.c
+++ b/coreutils/echo.c
@@ -50,7 +50,6 @@ int echo_main(int argc UNUSED_PARAM, char **argv)
        char *out;
        char *buffer;
        unsigned buflen;
-       int r;
 #if !ENABLE_FEATURE_FANCY_ECHO
        enum {
                eflag = '\\',
@@ -59,40 +58,40 @@ int echo_main(int argc UNUSED_PARAM, char **argv)
 
        argv++;
 #else
-       const char *p;
        char nflag = 1;
        char eflag = 0;
 
        while ((arg = *++argv) != NULL) {
-               if (!arg || arg[0] != '-')
-                       break;
+               char n, e;
+
+               if (arg[0] != '-')
+                       break; /* not an option arg, echo it */
 
                /* If it appears that we are handling options, then make sure
                 * that all of the options specified are actually valid.
                 * Otherwise, the string should just be echoed.
                 */
-               p = arg + 1;
-               if (!*p)        /* A single '-', so echo it. */
-                       break;
-
+               arg++;
+               n = nflag;
+               e = eflag;
                do {
-                       if (!strrchr("neE", *p))
+                       if (*arg == 'n')
+                               n = 0;
+                       else if (*arg == 'e')
+                               e = '\\';
+                       else if (*arg != 'E') {
+                               /* "-ccc" arg with one of c's invalid, echo it */
+                               /* arg consisting from just "-" also handled here */
                                goto just_echo;
-               } while (*++p);
-
-               /* All of the options in this arg are valid, so handle them. */
-               p = arg + 1;
-               do {
-                       if (*p == 'n')
-                               nflag = 0;
-                       if (*p == 'e')
-                               eflag = '\\';
-               } while (*++p);
+                       }
+               } while (*++arg);
+               nflag = n;
+               eflag = e;
        }
  just_echo:
 #endif
 
-       buflen = 1;
+       buflen = 0;
        pp = argv;
        while ((arg = *pp) != NULL) {
                buflen += strlen(arg) + 1;
@@ -106,29 +105,32 @@ int echo_main(int argc UNUSED_PARAM, char **argv)
                if (!eflag) {
                        /* optimization for very common case */
                        out = stpcpy(out, arg);
-               } else while ((c = *arg++)) {
-                       if (c == eflag) {       /* Check for escape seq. */
+               } else
+               while ((c = *arg++) != '\0') {
+                       if (c == eflag) {
+                               /* This is an "\x" sequence */
+
                                if (*arg == 'c') {
-                                       /* '\c' means cancel newline and
+                                       /* "\c" means cancel newline and
                                         * ignore all subsequent chars. */
                                        goto do_write;
                                }
-#if !ENABLE_FEATURE_FANCY_ECHO
-                               /* SUSv3 specifies that octal escapes must begin with '0'. */
-                               if ( ((int)(unsigned char)(*arg) - '0') >= 8) /* '8' or bigger */
-#endif
-                               {
-                                       /* Since SUSv3 mandates a first digit of 0, 4-digit octals
-                                       * of the form \0### are accepted. */
-                                       if (*arg == '0') {
-                                               /* NB: don't turn "...\0" into "...\" */
-                                               if (arg[1] && ((unsigned char)(arg[1]) - '0') < 8) {
-                                                       arg++;
-                                               }
+                               /* Since SUSv3 mandates a first digit of 0, 4-digit octals
+                               * of the form \0### are accepted. */
+                               if (*arg == '0') {
+                                       if ((unsigned char)(arg[1] - '0') < 8) {
+                                               /* 2nd char is 0..7: skip leading '0' */
+                                               arg++;
                                        }
-                                       /* bb_process_escape_sequence handles NUL correctly
-                                        * ("...\" case). */
-                                       c = bb_process_escape_sequence(&arg);
+                               }
+                               /* bb_process_escape_sequence handles NUL correctly
+                                * ("...\" case). */
+                               {
+                                       /* optimization: don't force arg to be on-stack,
+                                        * use another variable for that. ~30 bytes win */
+                                       const char *z = arg;
+                                       c = bb_process_escape_sequence(&z);
+                                       arg = z;
                                }
                        }
                        *out++ = c;
@@ -144,16 +146,18 @@ int echo_main(int argc UNUSED_PARAM, char **argv)
        }
 
  do_write:
-       r = full_write(STDOUT_FILENO, buffer, out - buffer);
+       /* Careful to error out on partial writes too (think ENOSPC!) */
+       errno = 0;
+       /*r =*/ full_write(STDOUT_FILENO, buffer, out - buffer);
        free(buffer);
-       if (r < 0) {
+       if (/*WRONG:r < 0*/ errno) {
                bb_perror_msg(bb_msg_write_error);
                return 1;
        }
        return 0;
 }
 
-/*-
+/*
  * Copyright (c) 1991, 1993
  *     The Regents of the University of California.  All rights reserved.
  *
@@ -239,7 +243,7 @@ int echo_main(int argc, char **argv)
                        goto just_echo;
 
                do {
-                       if (!strrchr("neE", *p))
+                       if (!strchr("neE", *p))
                                goto just_echo;
                } while (*++p);
 
@@ -265,27 +269,23 @@ int echo_main(int argc, char **argv)
                        /* optimization for very common case */
                        p += strlen(arg);
                } else while ((c = *arg++)) {
-                       if (c == eflag) {       /* Check for escape seq. */
+                       if (c == eflag) {
+                               /* This is an "\x" sequence */
+
                                if (*arg == 'c') {
-                                       /* '\c' means cancel newline and
+                                       /* "\c" means cancel newline and
                                         * ignore all subsequent chars. */
                                        cur_io->iov_len = p - (char*)cur_io->iov_base;
                                        cur_io++;
                                        goto ret;
                                }
-#if !ENABLE_FEATURE_FANCY_ECHO
-                               /* SUSv3 specifies that octal escapes must begin with '0'. */
-                               if ( (((unsigned char)*arg) - '1') >= 7)
-#endif
-                               {
-                                       /* Since SUSv3 mandates a first digit of 0, 4-digit octals
-                                       * of the form \0### are accepted. */
-                                       if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
-                                               arg++;
-                                       }
-                                       /* bb_process_escape_sequence can handle nul correctly */
-                                       c = bb_process_escape_sequence( (void*) &arg);
+                               /* Since SUSv3 mandates a first digit of 0, 4-digit octals
+                               * of the form \0### are accepted. */
+                               if (*arg == '0' && (unsigned char)(arg[1] - '0') < 8) {
+                                       arg++;
                                }
+                               /* bb_process_escape_sequence can handle nul correctly */
+                               c = bb_process_escape_sequence( (void*) &arg);
                        }
                        *p++ = c;
                }

diff --git a/testsuite/echo/echo-prints-dash b/testsuite/echo/echo-prints-dash
new file mode 100644 (file)
index 0000000..ddcdbad
--- /dev/null
+++ b/testsuite/echo/echo-prints-dash
@@ -0,0 +1 @@
+test "`busybox echo - | od -t x1 | head -n 1`" = "0000000 2d 0a"

diff --git a/testsuite/echo/echo-prints-non-opts b/testsuite/echo/echo-prints-non-opts
new file mode 100644 (file)
index 0000000..c7d1e20
--- /dev/null
+++ b/testsuite/echo/echo-prints-non-opts
@@ -0,0 +1 @@
+test "`busybox echo -neEZ | od -t x1 | head -n 1`" = "0000000 2d 6e 65 45 5a 0a"

diff --git a/testsuite/echo/echo-prints-slash_00041 b/testsuite/echo/echo-prints-slash_00041
new file mode 100644 (file)
index 0000000..9cffabd
--- /dev/null
+++ b/testsuite/echo/echo-prints-slash_00041
@@ -0,0 +1,3 @@
+# FEATURE: CONFIG_FEATURE_FANCY_ECHO
+
+test "`busybox echo -ne '\00041z' | od -t x1 | head -n 1`" = "0000000 04 31 7a"

diff --git a/testsuite/echo/echo-prints-slash_0041 b/testsuite/echo/echo-prints-slash_0041
new file mode 100644 (file)
index 0000000..b07429d
--- /dev/null
+++ b/testsuite/echo/echo-prints-slash_0041
@@ -0,0 +1,3 @@
+# FEATURE: CONFIG_FEATURE_FANCY_ECHO
+
+test "`busybox echo -ne '\0041z' | od -t x1 | head -n 1`" = "0000000 21 7a"

diff --git a/testsuite/echo/echo-prints-slash_041 b/testsuite/echo/echo-prints-slash_041
new file mode 100644 (file)
index 0000000..1d70cec
--- /dev/null
+++ b/testsuite/echo/echo-prints-slash_041
@@ -0,0 +1,3 @@
+# FEATURE: CONFIG_FEATURE_FANCY_ECHO
+
+test "`busybox echo -ne '\041z' | od -t x1 | head -n 1`" = "0000000 21 7a"

diff --git a/testsuite/echo/echo-prints-slash_41 b/testsuite/echo/echo-prints-slash_41
new file mode 100644 (file)
index 0000000..6d8999b
--- /dev/null
+++ b/testsuite/echo/echo-prints-slash_41
@@ -0,0 +1,3 @@
+# FEATURE: CONFIG_FEATURE_FANCY_ECHO
+
+test "`busybox echo -ne '\41z' | od -t x1 | head -n 1`" = "0000000 21 7a"