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-rw-r--r--lib/lib.c563
1 files changed, 563 insertions, 0 deletions
diff --git a/lib/lib.c b/lib/lib.c
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+++ b/lib/lib.c
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+/* vi: set sw=4 ts=4 :*/
+/* functions.c - reusable stuff.
+ *
+ * Functions with the x prefix are wrappers for library functions. They either
+ * succeed or kill the program with an error message, but never return failure.
+ * They usually have the same arguments and return value as the function they
+ * wrap.
+ *
+ * Copyright 2006 Rob Landley <rob@landley.net>
+ */
+
+#include "toys.h"
+
+void verror_msg(char *msg, int err, va_list va)
+{
+ fprintf(stderr, "%s: ", toys.which->name);
+ vfprintf(stderr, msg, va);
+ if (err) fprintf(stderr, ": %s", strerror(err));
+ putc('\n', stderr);
+}
+
+void error_msg(char *msg, ...)
+{
+ va_list va;
+
+ va_start(va, msg);
+ verror_msg(msg, 0, va);
+ va_end(va);
+}
+
+void perror_msg(char *msg, ...)
+{
+ va_list va;
+
+ va_start(va, msg);
+ verror_msg(msg, errno, va);
+ va_end(va);
+}
+
+// Die with an error message.
+void error_exit(char *msg, ...)
+{
+ va_list va;
+
+ va_start(va, msg);
+ verror_msg(msg, 0, va);
+ va_end(va);
+
+ exit(toys.exitval);
+}
+
+
+// Die with an error message and strerror(errno)
+void perror_exit(char *msg, ...)
+{
+ va_list va;
+
+ va_start(va, msg);
+ verror_msg(msg, errno, va);
+ va_end(va);
+
+ exit(toys.exitval);
+}
+
+// Stub until the online help system goes in.
+void usage_exit(void)
+{
+ exit(1);
+}
+
+// Like strncpy but always null terminated.
+void strlcpy(char *dest, char *src, size_t size)
+{
+ strncpy(dest,src,size);
+ dest[size-1] = 0;
+}
+
+// Die unless we can allocate memory.
+void *xmalloc(size_t size)
+{
+ void *ret = malloc(size);
+ if (!ret) error_exit("xmalloc");
+
+ return ret;
+}
+
+// Die unless we can allocate prezeroed memory.
+void *xzalloc(size_t size)
+{
+ void *ret = xmalloc(size);
+ bzero(ret,size);
+ return ret;
+}
+
+// Die unless we can change the size of an existing allocation, possibly
+// moving it. (Notice different arguments from libc function.)
+void xrealloc(void **ptr, size_t size)
+{
+ *ptr = realloc(*ptr, size);
+ if (!*ptr) error_exit("xrealloc");
+}
+
+// Die unless we can allocate a copy of this many bytes of string.
+void *xstrndup(char *s, size_t n)
+{
+ void *ret = xmalloc(++n);
+ strlcpy(ret, s, 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, ...)
+{
+ va_list va;
+ int len;
+ char *ret;
+
+ // How long is it?
+
+ va_start(va, format);
+ len = vsnprintf(0, 0, format, va);
+ len++;
+ va_end(va);
+
+ // Allocate and do the sprintf()
+ ret = xmalloc(len);
+ va_start(va, format);
+ vsnprintf(ret, len, format, va);
+ va_end(va);
+
+ return ret;
+}
+
+void xprintf(char *format, ...)
+{
+ va_list va;
+ va_start(va, format);
+
+ vprintf(format, va);
+ if (ferror(stdout)) perror_exit("write");
+}
+
+void xputc(char c)
+{
+ if (EOF == fputc(c, stdout)) perror_exit("write");
+}
+
+void xflush(void)
+{
+ if (fflush(stdout)) perror_exit("write");;
+}
+
+// Die unless we can exec argv[] (or run builtin command). Note that anything
+// with a path isn't a builtin, so /bin/sh won't match the builtin sh.
+void xexec(char **argv)
+{
+ toy_exec(argv);
+ execvp(argv[0], argv);
+ error_exit("No %s", argv[0]);
+}
+
+void xaccess(char *path, int flags)
+{
+ if (access(path, flags)) perror_exit("Can't access '%s'\n", path);
+}
+
+// Die unless we can open/create a file, returning file descriptor.
+int xcreate(char *path, int flags, int mode)
+{
+ int fd = open(path, flags, mode);
+ if (fd == -1) perror_exit("No file %s\n", path);
+ return fd;
+}
+
+// Die unless we can open a file, returning file descriptor.
+int xopen(char *path, int flags)
+{
+ return xcreate(path, flags, 0);
+}
+
+// Die unless we can open/create a file, returning FILE *.
+FILE *xfopen(char *path, char *mode)
+{
+ FILE *f = fopen(path, mode);
+ if (!f) perror_exit("No file %s\n", path);
+ return f;
+}
+
+// Keep reading until full or EOF
+ssize_t readall(int fd, void *buf, size_t len)
+{
+ size_t count = 0;
+ while (count<len) {
+ int i = read(fd, buf+count, len-count);
+ if (!i) return len;
+ if (i<0) return i;
+ count += i;
+ }
+
+ return count;
+}
+
+// Keep writing until done or EOF
+ssize_t writeall(int fd, void *buf, size_t len)
+{
+ size_t count = 0;
+ while (count<len) {
+ int i = write(fd, buf+count, len-count);
+ if (i<1) return i;
+ count += i;
+ }
+
+ return count;
+}
+
+// Die if there's an error other than EOF.
+size_t xread(int fd, void *buf, size_t len)
+{
+ len = read(fd, buf, len);
+ if (len < 0) perror_exit("xread");
+
+ return len;
+}
+
+void xreadall(int fd, void *buf, size_t len)
+{
+ if (len != readall(fd, buf, len)) perror_exit("xreadall");
+}
+
+// There's no xwriteall(), just xwrite(). When we read, there may or may not
+// be more data waiting. When we write, there is data and it had better go
+// somewhere.
+
+void xwrite(int fd, void *buf, size_t len)
+{
+ if (len != writeall(fd, buf, len)) perror_exit("xwrite");
+}
+
+char *xgetcwd(void)
+{
+ char *buf = getcwd(NULL, 0);
+ if (!buf) perror_exit("xgetcwd");
+
+ return buf;
+}
+
+void xstat(char *path, struct stat *st)
+{
+ if(stat(path, st)) perror_exit("Can't stat %s\n",path);
+}
+
+// Cannonicalizes path by removing ".", "..", and "//" elements. This is not
+// the same as realpath(), where "dir/.." could wind up somewhere else by
+// following symlinks.
+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;
+}
+
+// Find all file in a colon-separated path with access type "type" (generally
+// X_OK or R_OK). Returns a list of absolute paths to each file found, in
+// order.
+
+struct string_list *find_in_path(char *path, char *filename)
+{
+ struct string_list *rlist = NULL;
+ char *cwd = xgetcwd();
+
+ for (;;) {
+ char *next = path ? index(path, ':') : NULL;
+ int len = next ? next-path : strlen(path);
+ struct string_list *rnext;
+ struct stat st;
+
+ rnext = xmalloc(sizeof(void *) + strlen(filename)
+ + (len ? len : strlen(cwd)) + 2);
+ if (!len) sprintf(rnext->str, "%s/%s", cwd, filename);
+ else {
+ char *res = rnext->str;
+ strncpy(res, path, len);
+ res += len;
+ *(res++) = '/';
+ strcpy(res, filename);
+ }
+
+ // Confirm it's not a directory.
+ if (!stat(rnext->str, &st) && S_ISREG(st.st_mode)) {
+ rnext->next = rlist;
+ rlist = rnext;
+ } else free(rnext);
+
+ if (!next) break;
+ path += len;
+ path++;
+ }
+ free(cwd);
+
+ return rlist;
+
+}
+
+// Convert unsigned int to ascii, writing into supplied buffer. A truncated
+// result contains the first few digits of the result ala strncpy, and is
+// always null terminated (unless buflen is 0).
+void utoa_to_buf(unsigned n, char *buf, unsigned buflen)
+{
+ int i, out = 0;
+
+ if (buflen) {
+ for (i=1000000000; i; i/=10) {
+ int res = n/i;
+
+ if ((res || out || i == 1) && --buflen>0) {
+ out++;
+ n -= res*i;
+ *buf++ = '0' + res;
+ }
+ }
+ *buf = 0;
+ }
+}
+
+// Convert signed integer to ascii, using utoa_to_buf()
+void itoa_to_buf(int n, char *buf, unsigned buflen)
+{
+ if (buflen && n<0) {
+ n = -n;
+ *buf++ = '-';
+ buflen--;
+ }
+ utoa_to_buf((unsigned)n, buf, buflen);
+}
+
+// This static buffer is used by both utoa() and itoa(), calling either one a
+// second time will overwrite the previous results.
+//
+// The longest 32 bit integer is -2 billion plus a null terminator: 12 bytes.
+// Note that int is always 32 bits on any remotely unix-like system, see
+// http://www.unix.org/whitepapers/64bit.html for details.
+
+static char itoa_buf[12];
+
+// Convert unsigned integer to ascii, returning a static buffer.
+char *utoa(unsigned n)
+{
+ utoa_to_buf(n, itoa_buf, sizeof(itoa_buf));
+
+ return itoa_buf;
+}
+
+char *itoa(int n)
+{
+ itoa_to_buf(n, itoa_buf, sizeof(itoa_buf));
+
+ return itoa_buf;
+}
+
+// Return how long the file at fd is, if there's any way to determine it.
+off_t fdlength(int fd)
+{
+ off_t bottom = 0, top = 0, pos;
+ int size;
+
+ // If the ioctl works for this, return it.
+
+ if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512L;
+
+ // If not, do a binary search for the last location we can read. (Some
+ // block devices don't do BLKGETSIZE right.) This should probably have
+ // a CONFIG option...
+
+ do {
+ char temp;
+
+ pos = bottom + (top - bottom) / 2;
+
+ // If we can read from the current location, it's bigger.
+
+ if (lseek(fd, pos, 0)>=0 && read(fd, &temp, 1)==1) {
+ if (bottom == top) bottom = top = (top+1) * 2;
+ else bottom = pos;
+
+ // If we can't, it's smaller.
+
+ } else {
+ if (bottom == top) {
+ if (!top) return 0;
+ bottom = top/2;
+ } else top = pos;
+ }
+ } while (bottom + 1 != top);
+
+ return pos + 1;
+}
+
+/*
+ This might be of use or might not. Unknown yet...
+
+// Read contents of file as a single freshly allocated nul-terminated string.
+char *readfile(char *name)
+{
+ off_t len;
+ int fd;
+ char *buf;
+
+ fd = open(pidfile, O_RDONLY);
+ if (fd == -1) return 0;
+ len = fdlength(fd);
+ buf = xmalloc(len+1);
+ buf[xread(fd, buf, len)] = 0;
+
+ return buf;
+}
+
+char *xreadfile(char *name)
+{
+ char *buf = readfile(name);
+ if (!buf) perror_exit("xreadfile %s", name);
+ return buf;
+}
+
+*/
+
+// Open a /var/run/NAME.pid file, dying if we can't write it or if it currently
+// exists and is this executable.
+void xpidfile(char *name)
+{
+ char pidfile[256], spid[32];
+ int i, fd;
+ pid_t pid;
+
+ sprintf(pidfile, "/var/run/%s.pid", name);
+ // Try three times to open the sucker.
+ for (i=0; i<3; i++) {
+ fd = open(pidfile, O_CREAT|O_EXCL, 0644);
+ if (fd != -1) break;
+
+ // If it already existed, read it. Loop for race condition.
+ fd = open(pidfile, O_RDONLY);
+ if (fd == -1) continue;
+
+ // Is the old program still there?
+ spid[xread(fd, spid, sizeof(spid)-1)] = 0;
+ close(fd);
+ pid = atoi(spid);
+ if (fd < 1 || kill(pid, 0) == ESRCH) unlink(pidfile);
+
+ // An else with more sanity checking might be nice here.
+ }
+
+ if (i == 3) error_exit("xpidfile %s", name);
+
+ xwrite(fd, spid, sprintf(spid, "%ld\n", (long)getpid()));
+ close(fd);
+}
+
+// Create a dirtree node from a path.
+
+struct dirtree *read_dirtree_node(char *path)
+{
+ struct dirtree *dt;
+ char *name;
+
+ // Find last chunk of name.
+
+ for (;;) {
+ name = strrchr(path, '/');
+
+ if (!name) name = path;
+ else {
+ if (*(name+1)) name++;
+ else {
+ *name=0;
+ continue;
+ }
+ }
+ break;
+ }
+
+ dt = xzalloc(sizeof(struct dirtree)+strlen(name)+1);
+ xstat(path, &(dt->st));
+ strcpy(dt->name, name);
+
+ return dt;
+}
+
+// Given a directory (in a writeable PATH_MAX buffer), recursively read in a
+// directory tree.
+
+struct dirtree *read_dirtree(char *path)
+{
+ struct dirtree *dt = NULL, **ddt = &dt;
+ DIR *dir;
+ int len = strlen(path);
+
+ if (!(dir = opendir(path))) perror_msg("No %s", path);
+
+ for (;;) {
+ struct dirent *entry = readdir(dir);
+ if (!entry) break;
+
+ // Skip "." and ".."
+ if (entry->d_name[0]=='.') {
+ if (!entry->d_name[1]) continue;
+ if (entry->d_name[1]=='.' && !entry->d_name[2]) continue;
+ }
+
+ snprintf(path+len, sizeof(toybuf)-len, "/%s", entry->d_name);
+ *ddt = read_dirtree_node(path);
+ if (entry->d_type == DT_DIR) (*ddt)->child = read_dirtree(path);
+ ddt = &((*ddt)->next);
+ path[len]=0;
+ }
+
+ return dt;
+}