diff options
Diffstat (limited to 'app-shells/dash/files/dumb-echo.patch')
| -rw-r--r-- | app-shells/dash/files/dumb-echo.patch | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/app-shells/dash/files/dumb-echo.patch b/app-shells/dash/files/dumb-echo.patch new file mode 100644 index 00000000..89d51096 --- /dev/null +++ b/app-shells/dash/files/dumb-echo.patch @@ -0,0 +1,103 @@ +http://bugs.gentoo.org/337329 +http://bugs.gentoo.org/527848 +http://bugs.gentoo.org/590696 + +There's no requirement for `echo` to support escape sequences on systems +which are not XSI compliant (like embedded systems) according to POSIX: +http://pubs.opengroup.org/onlinepubs/9699919799/utilities/echo.html + +This behavior breaks historical scripts, espcially if also the (not required +by POSIX) `echo -n` and `echo -e` are unsupported, in particular all scripts +generated by autoconf-2.13 will break. + +Modern scripts better should avoid all these pitfalls and should always prefer +`printf` when they want anything like `echo -n` or interpretation of escape +sequences. So it might be useful to intentionally break scripts which rely on +these features. Note that this patch makes `echo` in dash behave differently +from any other existing shell. + +--- a/src/bltin/printf.c ++++ b/src/bltin/printf.c +@@ -442,21 +442,12 @@ + int + echocmd(int argc, char **argv) + { +- int nonl; +- +- nonl = *++argv ? equal(*argv, "-n") : 0; +- argv += nonl; +- +- do { +- int c; +- +- if (likely(*argv)) +- nonl += print_escape_str("%s", NULL, NULL, *argv++); +- if (nonl > 0) +- break; +- +- c = *argv ? ' ' : '\n'; +- out1c(c); +- } while (*argv); ++ int i; ++ for (i = 1; i < argc; ++i) { ++ outstr(argv[i], out1); ++ if (i < argc - 1) ++ outc(' ', out1); ++ } ++ outc('\n', out1); + return 0; + } +--- a/src/dash.1 ++++ b/src/dash.1 +@@ -1182,43 +1182,18 @@ + option turns off the effect of any preceding + .Fl P + options. +-.It Xo echo Op Fl n ++.It Xo echo + .Ar args... + .Xc + Print the arguments on the standard output, separated by spaces. +-Unless the +-.Fl n +-option is present, a newline is output following the arguments. +-.Pp +-If any of the following sequences of characters is encountered during +-output, the sequence is not output. Instead, the specified action is +-performed: +-.Bl -tag -width indent +-.It Li \eb +-A backspace character is output. +-.It Li \ec +-Subsequent output is suppressed. This is normally used at the end of the +-last argument to suppress the trailing newline that +-.Ic echo +-would otherwise output. +-.It Li \ef +-Output a form feed. +-.It Li \en +-Output a newline character. +-.It Li \er +-Output a carriage return. +-.It Li \et +-Output a (horizontal) tab character. +-.It Li \ev +-Output a vertical tab. +-.It Li \e0 Ns Ar digits +-Output the character whose value is given by zero to three octal digits. +-If there are zero digits, a nul character is output. +-.It Li \e\e +-Output a backslash. +-.El + .Pp +-All other backslash sequences elicit undefined behaviour. ++In this crippled version of dash no backslash sequences are supported. ++They will be printed out exactly as passed in. ++Also the option -n is not supported in this crippled version of dash. ++.Pp ++Moderns scripts might want to replace `echo -n ...` with the `printf %s ...` ++construct, and similarly use `printf` to for escape sequences. This is POSIX ++compliant though not compatible since some historical systems lack `printf`. + .It eval Ar string ... + Concatenate all the arguments with spaces. + Then re-parse and execute the command. |