diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/bfstd.c | 145 | ||||
| -rw-r--r-- | src/bfstd.h | 32 |
2 files changed, 147 insertions, 30 deletions
diff --git a/src/bfstd.c b/src/bfstd.c index 1f4bbb2..e5f9a31 100644 --- a/src/bfstd.c +++ b/src/bfstd.c @@ -17,6 +17,7 @@ #include <sys/types.h> #include <unistd.h> #include <wchar.h> +#include <wctype.h> #if BFS_USE_SYS_SYSMACROS_H # include <sys/sysmacros.h> @@ -253,6 +254,24 @@ void *xmemdup(const void *src, size_t size) { return ret; } +char *xstpecpy(char *dest, char *end, const char *src) { + return xstpencpy(dest, end, src, SIZE_MAX); +} + +char *xstpencpy(char *dest, char *end, const char *src, size_t n) { + size_t space = end - dest; + n = space < n ? space : n; + n = strnlen(src, n); + memcpy(dest, src, n); + if (n < space) { + dest[n] = '\0'; + return dest + n; + } else { + end[-1] = '\0'; + return end; + } +} + void xstrmode(mode_t mode, char str[11]) { strcpy(str, "----------"); @@ -555,48 +574,114 @@ size_t xstrwidth(const char *str) { return ret; } -char *wordesc(const char *str) { - size_t len = strlen(str); +/** Get the length of the longest printable prefix of a string. */ +static size_t printable_len(const char *str, size_t len) { + mbstate_t mb; + memset(&mb, 0, sizeof(mb)); - if (strcspn(str, "|&;<>()$`\\\"' \t\n*?[#˜=%") == len) { - // Whole string is safe - // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 - if (len > 0) { - return strdup(str); - } else { - return strdup("\"\""); + const char *cur = str; + while (len > 0) { + wchar_t wc; + size_t mblen = mbrtowc(&wc, cur, len, &mb); + if (mblen == (size_t)-1 || mblen == (size_t)-2 || !iswprint(wc)) { + break; } - } else if (strcspn(str, "`$\\\"") == len) { - // Safe to double-quote the whole string - // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02_03 - char *ret = malloc(len + 3); - if (!ret) { - return NULL; + cur += mblen; + len -= mblen; + } + + return cur - str; +} + +/** Get the length of the longest unprintable prefix of a string. */ +static size_t unprintable_len(const char *str, size_t len) { + mbstate_t mb; + memset(&mb, 0, sizeof(mb)); + + const char *cur = str; + while (len > 0) { + wchar_t wc; + size_t mblen = mbrtowc(&wc, cur, len, &mb); + if (mblen == (size_t)-1) { + // Invalid byte sequence, try again from the next byte + mblen = 1; + } else if (mblen == (size_t)-2) { + // Incomplete byte sequence, the rest is unprintable + mblen = len; + } else if (iswprint(wc)) { + break; } - char *cur = stpcpy(ret, "\""); - cur = stpcpy(cur, str); - cur = stpcpy(cur, "\""); - return ret; + cur += mblen; + len -= mblen; } - // Every ' is replaced with '\'', so at most a 3x growth - char *ret = malloc(3 * len + 3); + return cur - str; +} + +char *wordesc(const char *str) { + size_t len = strlen(str); + + // Worst case: every char is replaced with $'\xXX', so at most a 7x growth + size_t max_size = 7 * len + 3; + char *ret = malloc(max_size); if (!ret) { return NULL; } + char *cur = ret; + char *end = ret + max_size; - char *cur = stpcpy(ret, "'"); - while (*str) { - size_t chunk = strcspn(str, "'"); - cur = stpncpy(cur, str, chunk); - str += chunk; - if (*str) { - cur = stpcpy(cur, "'\\''"); - ++str; + while (len > 0) { + size_t plen = printable_len(str, len); + if (strcspn(str, "|&;<>()$`\\\"' *?[#˜=%") >= plen) { + // Whole chunk is safe + // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 + cur = xstpencpy(cur, end, str, plen); + } else if (strcspn(str, "`$\\\"") >= plen) { + // Safe to double-quote the whole chunk + // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02_03 + cur = xstpecpy(cur, end, "\""); + cur = xstpencpy(cur, end, str, plen); + cur = xstpecpy(cur, end, "\""); + } else { + // Single-quote the whole chunk, convert ' into '\'' + cur = xstpecpy(cur, end, "'"); + for (size_t i = 0; i < plen; ++i) { + if (str[i] == '\'') { + cur = xstpecpy(cur, end, "'\\''"); + } else { + cur = xstpencpy(cur, end, &str[i], 1); + } + } + cur = xstpecpy(cur, end, "'"); + } + + str += plen; + len -= plen; + if (len == 0) { + break; } + + // Non-printable characters, write them as $'\xXX\xXX...' + cur = xstpecpy(cur, end, "$'"); + size_t uplen = unprintable_len(str, len); + for (size_t i = 0; i < uplen; ++i) { + static const char *hex[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"}; + unsigned char byte = str[i]; + cur = xstpecpy(cur, end, "\\x"); + cur = xstpecpy(cur, end, hex[byte / 0x10]); + cur = xstpecpy(cur, end, hex[byte % 0x10]); + } + cur = xstpecpy(cur, end, "'"); + + str += uplen; + len -= uplen; + } + + if (cur == ret) { + cur = xstpecpy(cur, end, "\"\""); } - cur = stpcpy(cur, "'"); + bfs_assert(cur != end, "Result truncated!"); return ret; } diff --git a/src/bfstd.h b/src/bfstd.h index ebbcdb9..832db66 100644 --- a/src/bfstd.h +++ b/src/bfstd.h @@ -135,6 +135,38 @@ int ynprompt(void); void *xmemdup(const void *src, size_t size); /** + * A nice string copying function. + * + * @param dest + * The NUL terminator of the destination string, or `end` if it is + * already truncated. + * @param end + * The end of the destination buffer. + * @param src + * The string to copy from. + * @return + * The new NUL terminator of the destination, or `end` on truncation. + */ +char *xstpecpy(char *dest, char *end, const char *src); + +/** + * A nice string copying function. + * + * @param dest + * The NUL terminator of the destination string, or `end` if it is + * already truncated. + * @param end + * The end of the destination buffer. + * @param src + * The string to copy from. + * @param n + * The maximum number of characters to copy. + * @return + * The new NUL terminator of the destination, or `end` on truncation. + */ +char *xstpencpy(char *dest, char *end, const char *src, size_t n); + +/** * Format a mode like ls -l (e.g. -rw-r--r--). * * @param mode |