From 1e7a599671ccf1dccd21e02414f515efca069be6 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 12 Nov 2018 12:39:34 +0100 Subject: [PATCH] proc-cmdline: split out rd. prefix handling in proc_cmdline_parse_given() and proc_cmdline_get_key() This introduces a wrapper around extrac_first_word() called proc_cmdline_extract_first(), which suppresses "rd." parameters depending on the specified calls. This allows us to share more code between proc_cmdline_parse_given() and proc_cmdline_get_key(), and makes it easier to reuse this logic for other purposes. --- src/basic/proc-cmdline.c | 113 ++++++++++++++++++++++----------------- 1 file changed, 65 insertions(+), 48 deletions(-) diff --git a/src/basic/proc-cmdline.c b/src/basic/proc-cmdline.c index a52e58002eb..112f3b7aa2a 100644 --- a/src/basic/proc-cmdline.c +++ b/src/basic/proc-cmdline.c @@ -39,42 +39,71 @@ int proc_cmdline(char **ret) { return read_one_line_file("/proc/cmdline", ret); } +static int proc_cmdline_extract_first(const char **p, char **ret_word, ProcCmdlineFlags flags) { + const char *q = *p; + int r; + + for (;;) { + _cleanup_free_ char *word = NULL; + const char *c; + + r = extract_first_word(&q, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX); + if (r < 0) + return r; + if (r == 0) + break; + + /* Filter out arguments that are intended only for the initrd */ + c = startswith(word, "rd."); + if (c) { + if (!in_initrd()) + continue; + + if (FLAGS_SET(flags, PROC_CMDLINE_STRIP_RD_PREFIX)) { + r = free_and_strdup(&word, c); + if (r < 0) + return r; + } + + } else if (FLAGS_SET(flags, PROC_CMDLINE_RD_STRICT) && in_initrd()) + continue; /* And optionally filter out arguments that are intended only for the host */ + + *p = q; + *ret_word = TAKE_PTR(word); + return 1; + } + + *p = q; + *ret_word = NULL; + return 0; +} + int proc_cmdline_parse_given(const char *line, proc_cmdline_parse_t parse_item, void *data, ProcCmdlineFlags flags) { const char *p; int r; assert(parse_item); + /* The PROC_CMDLINE_VALUE_OPTIONAL flag doesn't really make sense for proc_cmdline_parse(), let's make this + * clear. */ + assert(!FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL)); + p = line; for (;;) { _cleanup_free_ char *word = NULL; - char *value, *key, *q; + char *value; - r = extract_first_word(&p, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX); + r = proc_cmdline_extract_first(&p, &word, flags); if (r < 0) return r; if (r == 0) break; - key = word; - - /* Filter out arguments that are intended only for the initrd */ - q = startswith(word, "rd."); - if (q) { - if (!in_initrd()) - continue; - - if (FLAGS_SET(flags, PROC_CMDLINE_STRIP_RD_PREFIX)) - key = q; - - } else if (FLAGS_SET(flags, PROC_CMDLINE_RD_STRICT) && in_initrd()) - continue; /* And optionally filter out arguments that are intended only for the host */ - - value = strchr(key, '='); + value = strchr(word, '='); if (value) *(value++) = 0; - r = parse_item(key, value, data); + r = parse_item(word, value, data); if (r < 0) return r; } @@ -127,29 +156,29 @@ bool proc_cmdline_key_streq(const char *x, const char *y) { return true; } -int proc_cmdline_get_key(const char *key, ProcCmdlineFlags flags, char **value) { +int proc_cmdline_get_key(const char *key, ProcCmdlineFlags flags, char **ret_value) { _cleanup_free_ char *line = NULL, *ret = NULL; bool found = false; const char *p; int r; - /* Looks for a specific key on the kernel command line. Supports two modes: + /* Looks for a specific key on the kernel command line. Supports three modes: * - * a) The "value" parameter is used. In this case a parameter beginning with the "key" string followed by "=" - * is searched, and the value following this is returned in "value". + * a) The "ret_value" parameter is used. In this case a parameter beginning with the "key" string followed by + * "=" is searched for, and the value following it is returned in "ret_value". * - * b) as above, but the PROC_CMDLINE_VALUE_OPTIONAL flag is set. In this case if the key is found as a - * separate word (i.e. not followed by "=" but instead by whitespace or the end of the command line), then - * this is also accepted, and "value" is returned as NULL. + * b) as above, but the PROC_CMDLINE_VALUE_OPTIONAL flag is set. In this case if the key is found as a separate + * word (i.e. not followed by "=" but instead by whitespace or the end of the command line), then this is + * also accepted, and "value" is returned as NULL. * - * c) The "value" parameter is NULL. In this case a search for the exact "key" parameter is performed. + * c) The "ret_value" parameter is NULL. In this case a search for the exact "key" parameter is performed. * * In all three cases, > 0 is returned if the key is found, 0 if not. */ if (isempty(key)) return -EINVAL; - if (FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL) && !value) + if (FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL) && !ret_value) return -EINVAL; r = proc_cmdline(&line); @@ -159,31 +188,17 @@ int proc_cmdline_get_key(const char *key, ProcCmdlineFlags flags, char **value) p = line; for (;;) { _cleanup_free_ char *word = NULL; - const char *e, *k, *q; - r = extract_first_word(&p, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX); + r = proc_cmdline_extract_first(&p, &word, flags); if (r < 0) return r; if (r == 0) break; - k = word; + if (ret_value) { + const char *e; - /* Automatically filter out arguments that are intended only for the initrd, if we are not in the - * initrd. */ - q = startswith(word, "rd."); - if (q) { - if (!in_initrd()) - continue; - - if (FLAGS_SET(flags, PROC_CMDLINE_STRIP_RD_PREFIX)) - k = q; - - } else if (FLAGS_SET(flags, PROC_CMDLINE_RD_STRICT) && in_initrd()) - continue; - - if (value) { - e = proc_cmdline_key_startswith(k, key); + e = proc_cmdline_key_startswith(word, key); if (!e) continue; @@ -198,13 +213,15 @@ int proc_cmdline_get_key(const char *key, ProcCmdlineFlags flags, char **value) found = true; } else { - if (streq(k, key)) + if (streq(word, key)) { found = true; + break; /* we found what we were looking for */ + } } } - if (value) - *value = TAKE_PTR(ret); + if (ret_value) + *ret_value = TAKE_PTR(ret); return found; }