GDB makes use of the libiberty function buildargv for splitting the inferior (program being debugged) argument string in the case where the inferior is not being started under a shell.
I have recently been working to improve this area of GDB, and have tracked done some of the unexpected behaviour to the libiberty function buildargv, and how it handles backslash escapes. For reference, I've been mostly reading: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html The issues that I would like to fix are: 1. Backslashes within single quotes should not be treated as an escape, thus: '\a' should split to \a, retaining the backslash. 2. Backslashes within double quotes should only act as an escape if they are immediately before one of the characters $ (dollar), ` (backtick), " (double quote), ` (backslash), or \n (newline). In all other cases a backslash should not be treated as an escape character. Thus: "\a" should split to \a, but "\$" should split to $. 3. A backslash-newline sequence should be treated as a line continuation, both the backslash and the newline should be removed. I've updated libiberty and also added some tests. All the existing libiberty tests continue to pass, but I'm not sure if there is more testing that should be done, buildargv is used within lto-wraper.cc, so maybe there's some testing folk can suggest that I run? --- libiberty/argv.c | 8 +++++-- libiberty/testsuite/test-expandargv.c | 34 +++++++++++++++++++++++++++ 2 files changed, 40 insertions(+), 2 deletions(-) diff --git a/libiberty/argv.c b/libiberty/argv.c index c2823d3e4ba..6bae4ca2ee9 100644 --- a/libiberty/argv.c +++ b/libiberty/argv.c @@ -224,9 +224,13 @@ char **buildargv (const char *input) if (bsquote) { bsquote = 0; - *arg++ = *input; + if (*input != '\n') + *arg++ = *input; } - else if (*input == '\\') + else if (*input == '\\' + && !squote + && (!dquote + || strchr ("$`\"\\\n", *(input + 1)) != NULL)) { bsquote = 1; } diff --git a/libiberty/testsuite/test-expandargv.c b/libiberty/testsuite/test-expandargv.c index 30f2337ef77..b8dcc6a269a 100644 --- a/libiberty/testsuite/test-expandargv.c +++ b/libiberty/testsuite/test-expandargv.c @@ -142,6 +142,40 @@ const char *test_data[] = { "b", 0, + /* Test 7 - No backslash removal within single quotes. */ + "'a\\$VAR' '\\\"'", /* Test 7 data */ + ARGV0, + "@test-expandargv-7.lst", + 0, + ARGV0, + "a\\$VAR", + "\\\"", + 0, + + /* Test 8 - Remove backslash / newline pairs. */ + "\"ab\\\ncd\" ef\\\ngh", /* Test 8 data */ + ARGV0, + "@test-expandargv-8.lst", + 0, + ARGV0, + "abcd", + "efgh", + 0, + + /* Test 9 - Backslash within double quotes. */ + "\"\\$VAR\" \"\\`\" \"\\\"\" \"\\\\\" \"\\n\" \"\\t\"", /* Test 9 data */ + ARGV0, + "@test-expandargv-9.lst", + 0, + ARGV0, + "$VAR", + "`", + "\"", + "\\", + "\\n", + "\\t", + 0, + 0 /* Test done marker, don't remove. */ }; base-commit: 458e7c937924bbcef80eb006af0b61420dbfc1c1 -- 2.25.4
