diff options
| -rw-r--r-- | lib/functions.c | 120 | ||||
| -rw-r--r-- | lib/lib.h | 6 |
2 files changed, 112 insertions, 14 deletions
diff --git a/lib/functions.c b/lib/functions.c index 44f21b55..0b003fd6 100644 --- a/lib/functions.c +++ b/lib/functions.c @@ -93,7 +93,7 @@ void xrealloc(void **ptr, size_t size) if (!*ptr) error_exit("xrealloc"); } -// Die unless we can allocate a copy of this string. +// Die unless we can allocate a copy of this many bytes of string. void *xstrndup(char *s, size_t n) { void *ret = xmalloc(++n); @@ -102,6 +102,12 @@ void *xstrndup(char *s, size_t n) return ret; } +// Die unless we can allocate a copy of this string. +void *xstrdup(char *s) +{ + return xstrndup(s,strlen(s)); +} + // Die unless we can allocate enough space to sprintf() into. char *xmsprintf(char *format, ...) { @@ -188,29 +194,117 @@ char *xgetcwd(void) return buf; } -// Find this file in a colon-separated path. +// Cannonicalizes path by removing ".", "..", and "//" elements. This is not +// the same as realpath(), where "dir/.." +char *xabspath(char *path) +{ + char *from, *to; + + // If this isn't an absolute path, make it one with cwd. + if (path[0]!='/') { + char *cwd=xgetcwd(); + path = xmsprintf("%s/%s",cwd,path); + free(cwd); + } else path = xstrdup(path); + + // Loop through path elements + from = to = path; + while (*from) { + + // Continue any current path component. + if (*from!='/') { + *(to++) = *(from++); + continue; + } + + // Skip duplicate slashes. + while (*from=='/') from++; + + // Start of a new filename. Handle . and .. + while (*from=='.') { + // Skip . + if (from[1]=='/') from += 2; + else if (!from[1]) from++; + // Back up for .. + else if (from[1]=='.') { + if (from[2]=='/') from +=3; + else if(!from[2]) from+=2; + else break; + while (to>path && *(--to)!='/'); + } else break; + } + // Add directory separator slash. + *(to++) = '/'; + } + *to = 0; + + return path; +} -char *find_in_path(char *path, char *filename) +// Check whether a file exists, or is executable, or... +int is_file_type(char *path, int type) { - char *next, *res = NULL, *cwd = xgetcwd(); + // Is there a file here we can execute? + if (!access(path, type)) { + struct stat st; + // Confirm it's not a directory. + if (!stat(path, &st) && S_ISREG(st.st_mode)) return 1; + } + + return 0; +} - while ((next = index(path,':'))) { - int len = next-path; - if (len==1) res = xmsprintf("%s/%s", cwd, filename); - else res = xmsprintf("%*s/%s",len-1,path,filename); - // Is there a file here we can execute? - if (!access(res, X_OK)) { - struct stat st; - // Confirm it's not a directory. - if (!stat(res, &st) && S_ISREG(st.st_mode)) break; +// Find an exectuable file either at a path with a slash in it (absolute or +// relative to current directory), or in $PATH. Returns absolute path to file, +// or NULL if not found. + + +char *which_in_path(char *filename) +{ + char *res; + + if (index(filename, '/')) { + res = xabspath(filename); + if (is_file_type(filename, X_OK)) return res; + free(res); + return NULL; + } + return find_in_path(getenv("PATH"), filename, X_OK); +} + +// Find file in a colon-separated path with access type "type" (generally +// X_OK or R_OK). Returns absolute path to file, or NULL if not found. + +char *find_in_path(char *path, char *filename, int type) +{ + char *res = NULL, *cwd = xgetcwd(); + + for (;;) { + char *next = path ? index(path, ':') : NULL; + int len = next ? next-path : strlen(path); + + if (!len) res = xmsprintf("%s/%s", cwd, filename); + else { + res = xmalloc(len+strlen(filename)+2); + strncpy(res, path, len); + res[len] = '/'; + strcpy(res+len+1, filename); } + + // Is there a file here we can execute? + if (is_file_type(res, type)) break; + free(res); res = NULL; + if (!next) break; + path += len; + path++; } free(cwd); return res; + } // Convert unsigned int to ascii, writing into supplied buffer. A truncated @@ -15,6 +15,7 @@ void *xmalloc(size_t size); void *xzalloc(size_t size); void xrealloc(void **ptr, size_t size); void *xstrndup(char *s, size_t n); +void *xstrdup(char *s); char *xmsprintf(char *format, ...); void xexec(char **argv); int xopen(char *path, int flags, int mode); @@ -23,7 +24,10 @@ ssize_t reread(int fd, void *buf, size_t count); ssize_t readall(int fd, void *buf, size_t count); void xread(int fd, char *buf, size_t count); char *xgetcwd(void); -char *find_in_path(char *path, char *filename); +char *xabspath(char *path); +int is_file_type(char *path, int type); +char *which_in_path(char *filename); +char *find_in_path(char *path, char *filename, int type); void utoa_to_buf(unsigned n, char *buf, unsigned buflen); void itoa_to_buf(int n, char *buf, unsigned buflen); char *utoa(unsigned n); |