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v260
src/basic/escape.c
618 строк
18 KB
DaanDeMeyer
escape: Make quote_command_line() argument const
10 июл 2025, 17:18
10 июл 2025, 17:18
6ed684d
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include <stdlib.h> #include <string.h> #include "alloc-util.h" #include "escape.h" #include "hexdecoct.h" #include "string-util.h" #include "strv.h" #include "utf8.h" int cescape_char(char c, char *buf) { char *buf_old = buf; /* Needs space for 4 characters in the buffer */ switch (c) { case '\a': *(buf++) = '\\'; *(buf++) = 'a'; break; case '\b': *(buf++) = '\\'; *(buf++) = 'b'; break; case '\f': *(buf++) = '\\'; *(buf++) = 'f'; break; case '\n': *(buf++) = '\\'; *(buf++) = 'n'; break; case '\r': *(buf++) = '\\'; *(buf++) = 'r'; break; case '\t': *(buf++) = '\\'; *(buf++) = 't'; break; case '\v': *(buf++) = '\\'; *(buf++) = 'v'; break; case '\\': *(buf++) = '\\'; *(buf++) = '\\'; break; case '"': *(buf++) = '\\'; *(buf++) = '"'; break; case '\'': *(buf++) = '\\'; *(buf++) = '\''; break; default: /* For special chars we prefer octal over * hexadecimal encoding, simply because glib's * g_strescape() does the same */ if ((c < ' ') || (c >= 127)) { *(buf++) = '\\'; *(buf++) = octchar((unsigned char) c >> 6); *(buf++) = octchar((unsigned char) c >> 3); *(buf++) = octchar((unsigned char) c); } else *(buf++) = c; break; } return buf - buf_old; } char* cescape_length(const char *s, size_t n) { const char *f; char *r, *t; /* Does C style string escaping. May be reversed with cunescape(). */ assert(s || n == 0); if (n == SIZE_MAX) n = strlen(s); if (n > (SIZE_MAX - 1) / 4) return NULL; r = new(char, n*4 + 1); if (!r) return NULL; for (f = s, t = r; f < s + n; f++) t += cescape_char(*f, t); *t = 0; return r; } int cunescape_one(const char *p, size_t length, char32_t *ret, bool *eight_bit, bool accept_nul) { int r = 1; assert(p); assert(ret); /* Unescapes C style. Returns the unescaped character in ret. * Sets *eight_bit to true if the escaped sequence either fits in * one byte in UTF-8 or is a non-unicode literal byte and should * instead be copied directly. */ if (length != SIZE_MAX && length < 1) return -EINVAL; switch (p[0]) { case 'a': *ret = '\a'; break; case 'b': *ret = '\b'; break; case 'f': *ret = '\f'; break; case 'n': *ret = '\n'; break; case 'r': *ret = '\r'; break; case 't': *ret = '\t'; break; case 'v': *ret = '\v'; break; case '\\': *ret = '\\'; break; case '"': *ret = '"'; break; case '\'': *ret = '\''; break; case 's': /* This is an extension of the XDG syntax files */ *ret = ' '; break; case 'x': { /* hexadecimal encoding */ int a, b; if (length != SIZE_MAX && length < 3) return -EINVAL; a = unhexchar(p[1]); if (a < 0) return -EINVAL; b = unhexchar(p[2]); if (b < 0) return -EINVAL; /* Don't allow NUL bytes */ if (a == 0 && b == 0 && !accept_nul) return -EINVAL; *ret = (a << 4U) | b; *eight_bit = true; r = 3; break; } case 'u': { /* C++11 style 16-bit unicode */ int a[4]; size_t i; uint32_t c; if (length != SIZE_MAX && length < 5) return -EINVAL; for (i = 0; i < 4; i++) { a[i] = unhexchar(p[1 + i]); if (a[i] < 0) return a[i]; } c = ((uint32_t) a[0] << 12U) | ((uint32_t) a[1] << 8U) | ((uint32_t) a[2] << 4U) | (uint32_t) a[3]; /* Don't allow 0 chars */ if (c == 0 && !accept_nul) return -EINVAL; *ret = c; r = 5; break; } case 'U': { /* C++11 style 32-bit unicode */ int a[8]; size_t i; char32_t c; if (length != SIZE_MAX && length < 9) return -EINVAL; for (i = 0; i < 8; i++) { a[i] = unhexchar(p[1 + i]); if (a[i] < 0) return a[i]; } c = ((uint32_t) a[0] << 28U) | ((uint32_t) a[1] << 24U) | ((uint32_t) a[2] << 20U) | ((uint32_t) a[3] << 16U) | ((uint32_t) a[4] << 12U) | ((uint32_t) a[5] << 8U) | ((uint32_t) a[6] << 4U) | (uint32_t) a[7]; /* Don't allow 0 chars */ if (c == 0 && !accept_nul) return -EINVAL; /* Don't allow invalid code points */ if (!unichar_is_valid(c)) return -EINVAL; *ret = c; r = 9; break; } case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': { /* octal encoding */ int a, b, c; char32_t m; if (length != SIZE_MAX && length < 3) return -EINVAL; a = unoctchar(p[0]); if (a < 0) return -EINVAL; b = unoctchar(p[1]); if (b < 0) return -EINVAL; c = unoctchar(p[2]); if (c < 0) return -EINVAL; /* don't allow NUL bytes */ if (a == 0 && b == 0 && c == 0 && !accept_nul) return -EINVAL; /* Don't allow bytes above 255 */ m = ((uint32_t) a << 6U) | ((uint32_t) b << 3U) | (uint32_t) c; if (m > 255) return -EINVAL; *ret = m; *eight_bit = true; r = 3; break; } default: return -EINVAL; } return r; } ssize_t cunescape_length_with_prefix(const char *s, size_t length, const char *prefix, UnescapeFlags flags, char **ret) { _cleanup_free_ char *ans = NULL; char *t; const char *f; size_t pl; int r; assert(s); assert(ret); /* Undoes C style string escaping, and optionally prefixes it. */ if (length == SIZE_MAX) length = strlen(s); pl = strlen_ptr(prefix); ans = new(char, pl+length+1); if (!ans) return -ENOMEM; if (prefix) memcpy(ans, prefix, pl); for (f = s, t = ans + pl; f < s + length; f++) { size_t remaining; bool eight_bit = false; char32_t u; remaining = s + length - f; assert(remaining > 0); if (*f != '\\') { /* A literal, copy verbatim */ *(t++) = *f; continue; } if (remaining == 1) { if (flags & UNESCAPE_RELAX) { /* A trailing backslash, copy verbatim */ *(t++) = *f; continue; } return -EINVAL; } r = cunescape_one(f + 1, remaining - 1, &u, &eight_bit, flags & UNESCAPE_ACCEPT_NUL); if (r < 0) { if (flags & UNESCAPE_RELAX) { /* Invalid escape code, let's take it literal then */ *(t++) = '\\'; continue; } return r; } f += r; if (eight_bit) /* One byte? Set directly as specified */ *(t++) = u; else /* Otherwise encode as multi-byte UTF-8 */ t += utf8_encode_unichar(t, u); } *t = 0; assert(t >= ans); /* Let static analyzers know that the answer is non-negative. */ *ret = TAKE_PTR(ans); return t - *ret; } char* xescape_full(const char *s, const char *bad, size_t console_width, XEscapeFlags flags) { char *ans, *t, *prev, *prev2; const char *f; assert(s); /* Escapes all chars in bad, in addition to \ and all special chars, in \xFF style escaping. May be * reversed with cunescape(). If XESCAPE_8_BIT is specified, characters >= 127 are let through * unchanged. This corresponds to non-ASCII printable characters in pre-unicode encodings. * * If console_width is reached, or XESCAPE_FORCE_ELLIPSIS is set, output is truncated and "..." is * appended. */ if (console_width == 0) return strdup(""); ans = new(char, MIN(strlen(s), console_width) * 4 + 1); if (!ans) return NULL; memset(ans, '_', MIN(strlen(s), console_width) * 4); ans[MIN(strlen(s), console_width) * 4] = 0; bool force_ellipsis = FLAGS_SET(flags, XESCAPE_FORCE_ELLIPSIS); for (f = s, t = prev = prev2 = ans; ; f++) { char *tmp_t = t; if (!*f) { if (force_ellipsis) break; *t = 0; return ans; } if ((unsigned char) *f < ' ' || (!FLAGS_SET(flags, XESCAPE_8_BIT) && (unsigned char) *f >= 127) || *f == '\\' || (bad && strchr(bad, *f))) { if ((size_t) (t - ans) + 4 + 3 * force_ellipsis > console_width) break; *(t++) = '\\'; *(t++) = 'x'; *(t++) = hexchar(*f >> 4); *(t++) = hexchar(*f); } else { if ((size_t) (t - ans) + 1 + 3 * force_ellipsis > console_width) break; *(t++) = *f; } /* We might need to go back two cycles to fit three dots, so remember two positions */ prev2 = prev; prev = tmp_t; } /* We can just write where we want, since chars are one-byte */ size_t c = MIN(console_width, 3u); /* If the console is too narrow, write fewer dots */ size_t off; if (console_width - c >= (size_t) (t - ans)) off = (size_t) (t - ans); else if (console_width - c >= (size_t) (prev - ans)) off = (size_t) (prev - ans); else if (console_width - c >= (size_t) (prev2 - ans)) off = (size_t) (prev2 - ans); else off = console_width - c; assert(off <= (size_t) (t - ans)); memcpy(ans + off, "...", c); ans[off + c] = '\0'; return ans; } char* escape_non_printable_full(const char *str, size_t console_width, XEscapeFlags flags) { if (FLAGS_SET(flags, XESCAPE_8_BIT)) return xescape_full(str, /* bad= */ NULL, console_width, flags); else return utf8_escape_non_printable_full(str, console_width, FLAGS_SET(flags, XESCAPE_FORCE_ELLIPSIS)); } char* octescape(const char *s, size_t len) { char *buf, *t; /* Escapes \ and " chars, in \nnn style escaping. */ assert(s || len == 0); if (len == SIZE_MAX) len = strlen(s); if (len > (SIZE_MAX - 1) / 4) return NULL; t = buf = new(char, len * 4 + 1); if (!buf) return NULL; for (size_t i = 0; i < len; i++) { uint8_t u = (uint8_t) s[i]; if (u < ' ' || u >= 127 || IN_SET(u, '\\', '"')) { *(t++) = '\\'; *(t++) = '0' + (u >> 6); *(t++) = '0' + ((u >> 3) & 7); *(t++) = '0' + (u & 7); } else *(t++) = u; } *t = 0; return buf; } char* decescape(const char *s, size_t len, const char *bad) { char *buf, *t; /* Escapes all chars in bad, in addition to \ and " chars, in \nnn decimal style escaping. */ assert(s || len == 0); if (len == SIZE_MAX) len = strlen(s); if (len > (SIZE_MAX - 1) / 4) return NULL; t = buf = new(char, len * 4 + 1); if (!buf) return NULL; for (size_t i = 0; i < len; i++) { uint8_t u = (uint8_t) s[i]; if (u < ' ' || u >= 127 || IN_SET(u, '\\', '"') || strchr(bad, u)) { *(t++) = '\\'; *(t++) = '0' + (u / 100); *(t++) = '0' + ((u / 10) % 10); *(t++) = '0' + (u % 10); } else *(t++) = u; } *t = 0; return buf; } static char* strcpy_backslash_escaped(char *t, const char *s, const char *bad) { assert(bad); assert(t); assert(s); while (*s) { int l = utf8_encoded_valid_unichar(s, SIZE_MAX); if (char_is_cc(*s) || l < 0) t += cescape_char(*(s++), t); else if (l == 1) { if (*s == '\\' || strchr(bad, *s)) *(t++) = '\\'; *(t++) = *(s++); } else { t = mempcpy(t, s, l); s += l; } } return t; } char* shell_escape(const char *s, const char *bad) { char *buf, *t; buf = new(char, strlen(s)*4+1); if (!buf) return NULL; t = strcpy_backslash_escaped(buf, s, bad); *t = 0; return buf; } char* shell_maybe_quote(const char *s, ShellEscapeFlags flags) { const char *p; char *buf, *t; assert(s); /* Encloses a string in quotes if necessary to make it OK as a shell string. */ if (FLAGS_SET(flags, SHELL_ESCAPE_EMPTY) && isempty(s)) return strdup("\"\""); /* We don't use $'' here in the POSIX mode. "" is fine too. */ for (p = s; *p; ) { int l = utf8_encoded_valid_unichar(p, SIZE_MAX); if (char_is_cc(*p) || l < 0 || strchr(WHITESPACE SHELL_NEED_QUOTES, *p)) break; p += l; } if (!*p) return strdup(s); buf = new(char, FLAGS_SET(flags, SHELL_ESCAPE_POSIX) + 1 + strlen(s)*4 + 1 + 1); if (!buf) return NULL; t = buf; if (FLAGS_SET(flags, SHELL_ESCAPE_POSIX)) { *(t++) = '$'; *(t++) = '\''; } else *(t++) = '"'; t = mempcpy(t, s, p - s); t = strcpy_backslash_escaped(t, p, FLAGS_SET(flags, SHELL_ESCAPE_POSIX) ? SHELL_NEED_ESCAPE_POSIX : SHELL_NEED_ESCAPE); if (FLAGS_SET(flags, SHELL_ESCAPE_POSIX)) *(t++) = '\''; else *(t++) = '"'; *t = 0; return str_realloc(buf); } char* quote_command_line(char * const *argv, ShellEscapeFlags flags) { _cleanup_free_ char *result = NULL; assert(argv); STRV_FOREACH(a, argv) { _cleanup_free_ char *t = NULL; t = shell_maybe_quote(*a, flags); if (!t) return NULL; if (!strextend_with_separator(&result, " ", t)) return NULL; } return str_realloc(TAKE_PTR(result)); }