359 lines
7.8 KiB
C
359 lines
7.8 KiB
C
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/*
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* I'm tired of doing "vsnprintf()" etc just to open a
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* file, so here's a "return static buffer with printf"
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* interface for paths.
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*
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* It's obviously not thread-safe. Sue me. But it's quite
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* useful for doing things like
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*
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* f = open(mkpath("%s/%s.perf", base, name), O_RDONLY);
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*
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* which is what it's designed for.
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*/
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#include "cache.h"
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static char bad_path[] = "/bad-path/";
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/*
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* Two hacks:
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*/
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static const char *get_perf_dir(void)
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{
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return ".";
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}
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size_t strlcpy(char *dest, const char *src, size_t size)
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{
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size_t ret = strlen(src);
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if (size) {
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size_t len = (ret >= size) ? size - 1 : ret;
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memcpy(dest, src, len);
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dest[len] = '\0';
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}
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return ret;
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}
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static char *get_pathname(void)
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{
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static char pathname_array[4][PATH_MAX];
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static int idx;
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return pathname_array[3 & ++idx];
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}
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static char *cleanup_path(char *path)
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{
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/* Clean it up */
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if (!memcmp(path, "./", 2)) {
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path += 2;
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while (*path == '/')
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path++;
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}
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return path;
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}
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char *mksnpath(char *buf, size_t n, const char *fmt, ...)
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{
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va_list args;
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unsigned len;
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va_start(args, fmt);
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len = vsnprintf(buf, n, fmt, args);
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va_end(args);
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if (len >= n) {
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strlcpy(buf, bad_path, n);
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return buf;
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}
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return cleanup_path(buf);
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}
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static char *perf_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
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{
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const char *perf_dir = get_perf_dir();
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size_t len;
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len = strlen(perf_dir);
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if (n < len + 1)
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goto bad;
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memcpy(buf, perf_dir, len);
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if (len && !is_dir_sep(perf_dir[len-1]))
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buf[len++] = '/';
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len += vsnprintf(buf + len, n - len, fmt, args);
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if (len >= n)
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goto bad;
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return cleanup_path(buf);
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bad:
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strlcpy(buf, bad_path, n);
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return buf;
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}
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char *perf_snpath(char *buf, size_t n, const char *fmt, ...)
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{
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va_list args;
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va_start(args, fmt);
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(void)perf_vsnpath(buf, n, fmt, args);
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va_end(args);
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return buf;
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}
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char *perf_pathdup(const char *fmt, ...)
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{
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char path[PATH_MAX];
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va_list args;
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va_start(args, fmt);
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(void)perf_vsnpath(path, sizeof(path), fmt, args);
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va_end(args);
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return xstrdup(path);
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}
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char *mkpath(const char *fmt, ...)
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{
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va_list args;
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unsigned len;
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char *pathname = get_pathname();
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va_start(args, fmt);
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len = vsnprintf(pathname, PATH_MAX, fmt, args);
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va_end(args);
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if (len >= PATH_MAX)
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return bad_path;
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return cleanup_path(pathname);
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}
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char *perf_path(const char *fmt, ...)
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{
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const char *perf_dir = get_perf_dir();
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char *pathname = get_pathname();
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va_list args;
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unsigned len;
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len = strlen(perf_dir);
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if (len > PATH_MAX-100)
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return bad_path;
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memcpy(pathname, perf_dir, len);
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if (len && perf_dir[len-1] != '/')
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pathname[len++] = '/';
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va_start(args, fmt);
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len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
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va_end(args);
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if (len >= PATH_MAX)
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return bad_path;
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return cleanup_path(pathname);
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}
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/* perf_mkstemp() - create tmp file honoring TMPDIR variable */
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int perf_mkstemp(char *path, size_t len, const char *template)
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{
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const char *tmp;
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size_t n;
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tmp = getenv("TMPDIR");
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if (!tmp)
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tmp = "/tmp";
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n = snprintf(path, len, "%s/%s", tmp, template);
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if (len <= n) {
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errno = ENAMETOOLONG;
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return -1;
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}
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return mkstemp(path);
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}
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const char *make_relative_path(const char *abs_path, const char *base)
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{
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static char buf[PATH_MAX + 1];
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int baselen;
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if (!base)
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return abs_path;
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baselen = strlen(base);
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if (prefixcmp(abs_path, base))
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return abs_path;
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if (abs_path[baselen] == '/')
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baselen++;
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else if (base[baselen - 1] != '/')
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return abs_path;
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strcpy(buf, abs_path + baselen);
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return buf;
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}
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/*
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* It is okay if dst == src, but they should not overlap otherwise.
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*
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* Performs the following normalizations on src, storing the result in dst:
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* - Ensures that components are separated by '/' (Windows only)
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* - Squashes sequences of '/'.
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* - Removes "." components.
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* - Removes ".." components, and the components the precede them.
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* Returns failure (non-zero) if a ".." component appears as first path
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* component anytime during the normalization. Otherwise, returns success (0).
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*
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* Note that this function is purely textual. It does not follow symlinks,
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* verify the existence of the path, or make any system calls.
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*/
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int normalize_path_copy(char *dst, const char *src)
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{
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char *dst0;
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if (has_dos_drive_prefix(src)) {
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*dst++ = *src++;
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*dst++ = *src++;
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}
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dst0 = dst;
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if (is_dir_sep(*src)) {
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*dst++ = '/';
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while (is_dir_sep(*src))
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src++;
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}
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for (;;) {
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char c = *src;
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/*
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* A path component that begins with . could be
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* special:
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* (1) "." and ends -- ignore and terminate.
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* (2) "./" -- ignore them, eat slash and continue.
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* (3) ".." and ends -- strip one and terminate.
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* (4) "../" -- strip one, eat slash and continue.
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*/
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if (c == '.') {
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if (!src[1]) {
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/* (1) */
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src++;
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} else if (is_dir_sep(src[1])) {
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/* (2) */
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src += 2;
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while (is_dir_sep(*src))
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src++;
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continue;
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} else if (src[1] == '.') {
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if (!src[2]) {
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/* (3) */
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src += 2;
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goto up_one;
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} else if (is_dir_sep(src[2])) {
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/* (4) */
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src += 3;
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while (is_dir_sep(*src))
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src++;
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goto up_one;
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}
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}
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}
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/* copy up to the next '/', and eat all '/' */
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while ((c = *src++) != '\0' && !is_dir_sep(c))
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*dst++ = c;
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if (is_dir_sep(c)) {
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*dst++ = '/';
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while (is_dir_sep(c))
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c = *src++;
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src--;
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} else if (!c)
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break;
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continue;
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up_one:
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/*
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* dst0..dst is prefix portion, and dst[-1] is '/';
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* go up one level.
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*/
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dst--; /* go to trailing '/' */
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if (dst <= dst0)
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return -1;
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/* Windows: dst[-1] cannot be backslash anymore */
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while (dst0 < dst && dst[-1] != '/')
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dst--;
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}
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*dst = '\0';
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return 0;
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}
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/*
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* path = Canonical absolute path
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* prefix_list = Colon-separated list of absolute paths
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*
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* Determines, for each path in prefix_list, whether the "prefix" really
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* is an ancestor directory of path. Returns the length of the longest
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* ancestor directory, excluding any trailing slashes, or -1 if no prefix
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* is an ancestor. (Note that this means 0 is returned if prefix_list is
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* "/".) "/foo" is not considered an ancestor of "/foobar". Directories
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* are not considered to be their own ancestors. path must be in a
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* canonical form: empty components, or "." or ".." components are not
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* allowed. prefix_list may be null, which is like "".
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*/
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int longest_ancestor_length(const char *path, const char *prefix_list)
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{
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char buf[PATH_MAX+1];
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const char *ceil, *colon;
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int len, max_len = -1;
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if (prefix_list == NULL || !strcmp(path, "/"))
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return -1;
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for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
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for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
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len = colon - ceil;
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if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
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continue;
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strlcpy(buf, ceil, len+1);
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if (normalize_path_copy(buf, buf) < 0)
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continue;
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len = strlen(buf);
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if (len > 0 && buf[len-1] == '/')
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buf[--len] = '\0';
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if (!strncmp(path, buf, len) &&
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path[len] == '/' &&
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len > max_len) {
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max_len = len;
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}
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}
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return max_len;
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}
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/* strip arbitrary amount of directory separators at end of path */
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static inline int chomp_trailing_dir_sep(const char *path, int len)
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{
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while (len && is_dir_sep(path[len - 1]))
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len--;
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return len;
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}
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/*
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* If path ends with suffix (complete path components), returns the
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* part before suffix (sans trailing directory separators).
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* Otherwise returns NULL.
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*/
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char *strip_path_suffix(const char *path, const char *suffix)
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{
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int path_len = strlen(path), suffix_len = strlen(suffix);
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while (suffix_len) {
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if (!path_len)
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return NULL;
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if (is_dir_sep(path[path_len - 1])) {
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if (!is_dir_sep(suffix[suffix_len - 1]))
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return NULL;
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path_len = chomp_trailing_dir_sep(path, path_len);
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suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
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}
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else if (path[--path_len] != suffix[--suffix_len])
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return NULL;
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}
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if (path_len && !is_dir_sep(path[path_len - 1]))
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return NULL;
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return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
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}
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