diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/lib.c | 469 | ||||
| -rw-r--r-- | lib/lib.h | 31 | ||||
| -rw-r--r-- | lib/xwrap.c | 470 |
3 files changed, 488 insertions, 482 deletions
@@ -1,28 +1,10 @@ -/* 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. +/* lib.c - various reusable stuff. * * 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 xstrncpy(char *dest, char *src, size_t size) -{ - if (strlen(src)+1 > size) error_exit("xstrcpy"); - strcpy(dest, src); -} - -void xexit(void) -{ - if (toys.rebound) longjmp(*toys.rebound, 1); - else exit(toys.exitval); -} - void verror_msg(char *msg, int err, va_list va) { char *s = ": %s"; @@ -67,7 +49,6 @@ void error_exit(char *msg, ...) xexit(); } - // Die with an error message and strerror(errno) void perror_exit(char *msg, ...) { @@ -80,153 +61,6 @@ void perror_exit(char *msg, ...) xexit(); } -// 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); - memset(ret, 0, 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) || fflush(stdout)) perror_exit("write"); -} - -void xputc(char c) -{ - if (EOF == fputc(c, stdout) || fflush(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); - - perror_exit("exec %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"); -} - -int xdup(int fd) -{ - if (fd != -1) { - fd = dup(fd); - if (fd == -1) perror_exit("xdup"); - } - return fd; -} - -// 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) { @@ -255,39 +89,6 @@ ssize_t writeall(int fd, void *buf, size_t len) return count; } -// Die if there's an error other than EOF. -size_t xread(int fd, void *buf, size_t len) -{ - ssize_t ret = read(fd, buf, len); - if (ret < 0) perror_exit("xread"); - - return ret; -} - -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; -} - off_t lskip(int fd, off_t offset) { off_t and = lseek(fd, offset, SEEK_CUR); @@ -309,19 +110,6 @@ off_t lskip(int fd, off_t 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); -} - // Split a path into linked list of components, tracking head and tail of list. // Filters out // entries with no contents. struct string_list **splitpath(char *path, struct string_list **list) @@ -347,171 +135,6 @@ struct string_list **splitpath(char *path, struct string_list **list) return list; } -// Cannonicalize path, even to file with one or more missing components at end. -// if exact, require last path component to exist -char *xabspath(char *path, int exact) -{ - struct string_list *todo, *done = 0; - int try = 9999, dirfd = open("/", 0);; - char buf[4096], *ret; - - // If this isn't an absolute path, start with cwd. - if (*path != '/') { - char *temp = xgetcwd(); - - splitpath(path, splitpath(temp, &todo)); - free(temp); - } else splitpath(path, &todo); - - // Iterate through path components - while (todo) { - struct string_list *new = llist_pop(&todo), **tail; - ssize_t len; - - if (!try--) { - errno = ELOOP; - goto error; - } - - // Removable path componenents. - if (!strcmp(new->str, ".") || !strcmp(new->str, "..")) { - int x = new->str[1]; - - free(new); - if (x) { - if (done) free(llist_pop(&done)); - len = 0; - } else continue; - - // Is this a symlink? - } else len=readlinkat(dirfd, new->str, buf, 4096); - - if (len>4095) goto error; - if (len<1) { - int fd; - char *s = ".."; - - // For .. just move dirfd - if (len) { - // Not a symlink: add to linked list, move dirfd, fail if error - if ((exact || todo) && errno != EINVAL) goto error; - new->next = done; - done = new; - if (errno == EINVAL && !todo) break; - s = new->str; - } - fd = openat(dirfd, s, 0); - if (fd == -1 && (exact || todo || errno != ENOENT)) goto error; - close(dirfd); - dirfd = fd; - continue; - } - - // If this symlink is to an absolute path, discard existing resolved path - buf[len] = 0; - if (*buf == '/') { - llist_traverse(done, free); - done=0; - close(dirfd); - dirfd = open("/", 0); - } - free(new); - - // prepend components of new path. Note symlink to "/" will leave new NULL - tail = splitpath(buf, &new); - - // symlink to "/" will return null and leave tail alone - if (new) { - *tail = todo; - todo = new; - } - } - close(dirfd); - - // At this point done has the path, in reverse order. Reverse list while - // calculating buffer length. - - try = 2; - while (done) { - struct string_list *temp = llist_pop(&done);; - - if (todo) try++; - try += strlen(temp->str); - temp->next = todo; - todo = temp; - } - - // Assemble return buffer - - ret = xmalloc(try); - *ret = '/'; - ret [try = 1] = 0; - while (todo) { - if (try>1) ret[try++] = '/'; - try = stpcpy(ret+try, todo->str) - ret; - free(llist_pop(&todo)); - } - - return ret; - -error: - close(dirfd); - llist_traverse(todo, free); - llist_traverse(done, free); - - return NULL; -} - -// Resolve all symlinks, returning malloc() memory. -char *xrealpath(char *path) -{ - char *new = realpath(path, NULL); - if (!new) perror_exit("realpath '%s'", path); - return new; -} - -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. @@ -692,30 +315,6 @@ off_t fdlength(int fd) 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; - } - } -} - // Read contents of file as a single freshly allocated nul-terminated string. char *readfile(char *name) { @@ -732,13 +331,6 @@ char *readfile(char *name) return buf; } -char *xreadfile(char *name) -{ - char *buf = readfile(name); - if (!buf) perror_exit("xreadfile %s", name); - return buf; -} - // Sleep for this many thousandths of a second void msleep(long miliseconds) { @@ -749,17 +341,6 @@ void msleep(long miliseconds) nanosleep(&ts, &ts); } -int xioctl(int fd, int request, void *data) -{ - int rc; - - errno = 0; - rc = ioctl(fd, request, data); - if (rc == -1 && errno) perror_exit("ioctl %x", request); - - return rc; -} - int64_t peek(void *ptr, int size) { if (size & 8) { @@ -794,39 +375,6 @@ void poke(void *ptr, uint64_t val, int size) } } -// 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 (pid < 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 @@ -890,21 +438,6 @@ char *get_line(int fd) 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); - } -} - int wfchmodat(int fd, char *name, mode_t mode) { int rc = fchmodat(fd, name, mode, 0); @@ -85,14 +85,9 @@ struct dirtree *dirtree_read(char *path, int (*callback)(struct dirtree *node)); void show_help(void); -// lib.c +// xfuncs.c void xstrncpy(char *dest, char *src, size_t size); void xexit(void) noreturn; -void verror_msg(char *msg, int err, va_list va); -void error_msg(char *msg, ...); -void perror_msg(char *msg, ...); -void error_exit(char *msg, ...) noreturn; -void perror_exit(char *msg, ...) noreturn; void *xmalloc(size_t size); void *xzalloc(size_t size); void *xrealloc(void *ptr, size_t size); @@ -111,19 +106,12 @@ int xopen(char *path, int flags); void xclose(int fd); int xdup(int fd); FILE *xfopen(char *path, char *mode); -ssize_t readall(int fd, void *buf, size_t len); -ssize_t writeall(int fd, void *buf, size_t len); size_t xread(int fd, void *buf, size_t len); void xreadall(int fd, void *buf, size_t len); void xwrite(int fd, void *buf, size_t len); off_t xlseek(int fd, off_t offset, int whence); -off_t lskip(int fd, off_t offset); -char *readfile(char *name); char *xreadfile(char *name); -void msleep(long miliseconds); int xioctl(int fd, int request, void *data); -int64_t peek(void *ptr, int size); -void poke(void *ptr, uint64_t val, int size); char *xgetcwd(void); void xstat(char *path, struct stat *st); char *xabspath(char *path, int exact); @@ -131,6 +119,22 @@ char *xrealpath(char *path); void xchdir(char *path); void xmkpath(char *path, int mode); void xsetuid(uid_t uid); +char *xreadlink(char *name); + +// lib.c +void verror_msg(char *msg, int err, va_list va); +void error_msg(char *msg, ...); +void perror_msg(char *msg, ...); +void error_exit(char *msg, ...) noreturn; +void perror_exit(char *msg, ...) noreturn; +ssize_t readall(int fd, void *buf, size_t len); +ssize_t writeall(int fd, void *buf, size_t len); +off_t lskip(int fd, off_t offset); +struct string_list **splitpath(char *path, struct string_list **list); +char *readfile(char *name); +void msleep(long miliseconds); +int64_t peek(void *ptr, int size); +void poke(void *ptr, uint64_t val, int size); struct string_list *find_in_path(char *path, char *filename); void utoa_to_buf(unsigned n, char *buf, unsigned buflen); void itoa_to_buf(int n, char *buf, unsigned buflen); @@ -140,7 +144,6 @@ long atolx(char *c); int numlen(long l); int stridx(char *haystack, char needle); off_t fdlength(int fd); -char *xreadlink(char *name); void loopfiles_rw(char **argv, int flags, int permissions, int failok, void (*function)(int fd, char *name)); void loopfiles(char **argv, void (*function)(int fd, char *name)); diff --git a/lib/xwrap.c b/lib/xwrap.c new file mode 100644 index 00000000..b0029eef --- /dev/null +++ b/lib/xwrap.c @@ -0,0 +1,470 @@ +/* xwrap.c - wrappers around existing library functions. + * + * Functions with the x prefix are wrappers that 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 xstrncpy(char *dest, char *src, size_t size) +{ + if (strlen(src)+1 > size) error_exit("xstrcpy"); + strcpy(dest, src); +} + +void xexit(void) +{ + if (toys.rebound) longjmp(*toys.rebound, 1); + else exit(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); + memset(ret, 0, 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) || fflush(stdout)) perror_exit("write"); +} + +void xputc(char c) +{ + if (EOF == fputc(c, stdout) || fflush(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); + + perror_exit("exec %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"); +} + +int xdup(int fd) +{ + if (fd != -1) { + fd = dup(fd); + if (fd == -1) perror_exit("xdup"); + } + return fd; +} + +// 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; +} + +// Die if there's an error other than EOF. +size_t xread(int fd, void *buf, size_t len) +{ + ssize_t ret = read(fd, buf, len); + if (ret < 0) perror_exit("xread"); + + return ret; +} + +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); +} + +// Cannonicalize path, even to file with one or more missing components at end. +// if exact, require last path component to exist +char *xabspath(char *path, int exact) +{ + struct string_list *todo, *done = 0; + int try = 9999, dirfd = open("/", 0);; + char buf[4096], *ret; + + // If this isn't an absolute path, start with cwd. + if (*path != '/') { + char *temp = xgetcwd(); + + splitpath(path, splitpath(temp, &todo)); + free(temp); + } else splitpath(path, &todo); + + // Iterate through path components + while (todo) { + struct string_list *new = llist_pop(&todo), **tail; + ssize_t len; + + if (!try--) { + errno = ELOOP; + goto error; + } + + // Removable path componenents. + if (!strcmp(new->str, ".") || !strcmp(new->str, "..")) { + int x = new->str[1]; + + free(new); + if (x) { + if (done) free(llist_pop(&done)); + len = 0; + } else continue; + + // Is this a symlink? + } else len=readlinkat(dirfd, new->str, buf, 4096); + + if (len>4095) goto error; + if (len<1) { + int fd; + char *s = ".."; + + // For .. just move dirfd + if (len) { + // Not a symlink: add to linked list, move dirfd, fail if error + if ((exact || todo) && errno != EINVAL) goto error; + new->next = done; + done = new; + if (errno == EINVAL && !todo) break; + s = new->str; + } + fd = openat(dirfd, s, 0); + if (fd == -1 && (exact || todo || errno != ENOENT)) goto error; + close(dirfd); + dirfd = fd; + continue; + } + + // If this symlink is to an absolute path, discard existing resolved path + buf[len] = 0; + if (*buf == '/') { + llist_traverse(done, free); + done=0; + close(dirfd); + dirfd = open("/", 0); + } + free(new); + + // prepend components of new path. Note symlink to "/" will leave new NULL + tail = splitpath(buf, &new); + + // symlink to "/" will return null and leave tail alone + if (new) { + *tail = todo; + todo = new; + } + } + close(dirfd); + + // At this point done has the path, in reverse order. Reverse list while + // calculating buffer length. + + try = 2; + while (done) { + struct string_list *temp = llist_pop(&done);; + + if (todo) try++; + try += strlen(temp->str); + temp->next = todo; + todo = temp; + } + + // Assemble return buffer + + ret = xmalloc(try); + *ret = '/'; + ret [try = 1] = 0; + while (todo) { + if (try>1) ret[try++] = '/'; + try = stpcpy(ret+try, todo->str) - ret; + free(llist_pop(&todo)); + } + + return ret; + +error: + close(dirfd); + llist_traverse(todo, free); + llist_traverse(done, free); + + return NULL; +} + +// Resolve all symlinks, returning malloc() memory. +char *xrealpath(char *path) +{ + char *new = realpath(path, NULL); + if (!new) perror_exit("realpath '%s'", path); + return new; +} + +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"); +} + +// 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; + } + } +} + +char *xreadfile(char *name) +{ + char *buf = readfile(name); + if (!buf) perror_exit("xreadfile %s", name); + return buf; +} + +int xioctl(int fd, int request, void *data) +{ + int rc; + + errno = 0; + rc = ioctl(fd, request, data); + if (rc == -1 && errno) perror_exit("ioctl %x", request); + + return rc; +} + +// 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 (pid < 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); +} + +// 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); + } +} |