/* vi: set sw=4 ts=4 :*/ /* lib.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" // Strcpy with size checking: exit if there's not enough space for the string. void xstrcpy(char *dest, char *src, size_t size) { if (strlen(src)+1 > size) error_exit("xstrcpy"); strcpy(dest, src); } void verror_msg(char *msg, int err, va_list va) { char *s = ": %s"; fprintf(stderr, "%s: ", toys.which->name); if (msg) vfprintf(stderr, msg, va); else s+=2; 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; if (CFG_HELP && toys.exithelp) { *toys.optargs=*toys.argv; USE_HELP(help_main();) // dear gcc: shut up. fprintf(stderr,"\n"); } va_start(va, msg); verror_msg(msg, 0, va); va_end(va); exit(!toys.exitval ? 1 : 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 ? 1 : toys.exitval); } // 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"); return ptr; } // Die unless we can allocate a copy of this many bytes of string. char *xstrndup(char *s, size_t n) { char *ret = xmalloc(++n); strncpy(ret, s, n); ret[--n]=0; return ret; } // Die unless we can allocate a copy of this string. char *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, va2; int len; char *ret; va_start(va, format); va_copy(va2, va); // How long is it? len = vsnprintf(0, 0, format, va); len++; va_end(va); // Allocate and do the sprintf() ret = xmalloc(len); vsnprintf(ret, len, format, va2); va_end(va2); return ret; } void xprintf(char *format, ...) { va_list va; va_start(va, format); vprintf(format, va); if (ferror(stdout)) perror_exit("write"); } void xputs(char *s) { if (EOF == puts(s)) 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'", path); } // Die unless we can delete a file. (File must exist to be deleted.) void xunlink(char *path) { if (unlink(path)) perror_exit("unlink '%s'", 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("%s", path); return fd; } // Die unless we can open a file, returning file descriptor. int xopen(char *path, int flags) { return xcreate(path, flags, 0); } void xclose(int fd) { if (close(fd)) perror_exit("xclose"); } // 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", 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) break; 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"); } // Die if lseek fails, probably due to being called on a pipe. off_t xlseek(int fd, off_t offset, int whence) { offset = lseek(fd, offset, whence); if (offset<0) perror_exit("lseek"); return offset; } 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", 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; } void xchdir(char *path) { if (chdir(path)) error_exit("chdir '%s'", path); } // Ensure entire path exists. // If mode != -1 set permissions on newly created dirs. // Requires that path string be writable (for temporary null terminators). void xmkpath(char *path, int mode) { char *p, old; mode_t mask; int rc; struct stat st; for (p = path; ; p++) { if (!*p || *p == '/') { old = *p; *p = rc = 0; if (stat(path, &st) || !S_ISDIR(st.st_mode)) { if (mode != -1) { mask=umask(0); rc = mkdir(path, mode); umask(mask); } else rc = mkdir(path, 0777); } *p = old; if(rc) perror_exit("mkpath '%s'", path); } if (!*p) break; } } // setuid() can fail (for example, too many processes belonging to that user), // which opens a security hole if the process continues as the original user. void xsetuid(uid_t uid) { if (setuid(uid)) perror_exit("xsetuid"); } // 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, **prlist=&rlist; 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)) { *prlist = rnext; rnext->next = NULL; prlist = &(rnext->next); } 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; } // atol() with the kilo/mega/giga/tera/peta/exa extensions. // (zetta and yotta don't fit in 64 bits.) long atolx(char *c) { char *suffixes="kmgtpe", *end; long val = strtol(c, &c, 0); if (*c) { end = strchr(suffixes, tolower(*c)); if (end) val *= 1024L<<((end-suffixes)*10); } return val; } // 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, old; 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... old = lseek(fd, 0, SEEK_CUR); 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); lseek(fd, old, SEEK_SET); return pos + 1; } // This can return null (meaning file not found). It just won't return null // for memory allocation reasons. char *xreadlink(char *name) { int len, size = 0; char *buf = 0; // Grow by 64 byte chunks until it's big enough. for(;;) { size +=64; buf = xrealloc(buf, size); len = readlink(name, buf, size); if (len<0) { free(buf); return 0; } if (len<size) { buf[len]=0; return buf; } } } /* 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(name, O_RDONLY); if (fd == -1) return 0; len = fdlength(fd); buf = xmalloc(len+1); buf[readall(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); } // Iterate through an array of files, opening each one and calling a function // on that filehandle and name. The special filename "-" means stdin if // flags is O_RDONLY, stdout otherwise. An empty argument list calls // function() on just stdin/stdout. // // Note: read only filehandles are automatically closed when function() // returns, but writeable filehandles must be close by function() void loopfiles_rw(char **argv, int flags, void (*function)(int fd, char *name)) { int fd; // If no arguments, read from stdin. if (!*argv) function(flags ? 1 : 0, "-"); else do { // Filename "-" means read from stdin. // Inability to open a file prints a warning, but doesn't exit. if (!strcmp(*argv,"-")) fd=0; else if (0>(fd = open(*argv, flags, 0666))) { perror_msg("%s", *argv); toys.exitval = 1; continue; } function(fd, *argv); if (!flags) close(fd); } while (*++argv); } // Call loopfiles_rw with O_RDONLY (common case). void loopfiles(char **argv, void (*function)(int fd, char *name)) { loopfiles_rw(argv, O_RDONLY, function); } // Slow, but small. char *get_rawline(int fd, long *plen, char end) { char c, *buf = NULL; long len = 0; for (;;) { if (1>read(fd, &c, 1)) break; if (!(len & 63)) buf=xrealloc(buf, len+65); if ((buf[len++]=c) == end) break; } if (buf) buf[len]=0; if (plen) *plen = len; return buf; } char *get_line(int fd) { long len; char *buf = get_rawline(fd, &len, '\n'); if (buf && buf[--len]=='\n') buf[len]=0; return buf; } // Copy the rest of in to out and close both files. void xsendfile(int in, int out) { long len; char buf[4096]; if (in<0) return; for (;;) { len = xread(in, buf, 4096); if (len<1) break; xwrite(out, buf, len); } } // Open a temporary file to copy an existing file into. int copy_tempfile(int fdin, char *name, char **tempname) { struct stat statbuf; int fd; *tempname = xstrndup(name, strlen(name)+6); strcat(*tempname,"XXXXXX"); if(-1 == (fd = mkstemp(*tempname))) error_exit("no temp file"); // Set permissions of output file fstat(fdin, &statbuf); fchmod(fd, statbuf.st_mode); return fd; } // Abort the copy and delete the temporary file. void delete_tempfile(int fdin, int fdout, char **tempname) { close(fdin); close(fdout); unlink(*tempname); free(*tempname); *tempname = NULL; } // Copy the rest of the data and replace the original with the copy. void replace_tempfile(int fdin, int fdout, char **tempname) { char *temp = xstrdup(*tempname); temp[strlen(temp)-6]=0; if (fdin != -1) { xsendfile(fdin, fdout); xclose(fdin); } xclose(fdout); rename(*tempname, temp); free(*tempname); free(temp); *tempname = NULL; } // Create a 256 entry CRC32 lookup table. void crc_init(unsigned int *crc_table, int little_endian) { unsigned int i; // Init the CRC32 table (big endian) for (i=0; i<256; i++) { unsigned int j, c = little_endian ? i : i<<24; for (j=8; j; j--) if (little_endian) c = (c&1) ? (c>>1)^0xEDB88320 : c>>1; else c=c&0x80000000 ? (c<<1)^0x04c11db7 : (c<<1); crc_table[i] = c; } }