From f6f7bfb8e0a257137f8c2dad83ae4ed826b4e4bb Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Tue, 22 Oct 2002 12:24:59 +0000 Subject: last_patch63 from vodz: add in crond and crontab applets --- miscutils/crontab.c | 393 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 393 insertions(+) create mode 100644 miscutils/crontab.c (limited to 'miscutils/crontab.c') diff --git a/miscutils/crontab.c b/miscutils/crontab.c new file mode 100644 index 000000000..c86990653 --- /dev/null +++ b/miscutils/crontab.c @@ -0,0 +1,393 @@ +/* + * CRONTAB + * + * usually setuid root, -c option only works if getuid() == geteuid() + * + * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com) + * May be distributed under the GNU General Public License + * + * Vladimir Oleynik (C) 2002 to be used in busybox + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef CRONTABS +#define CRONTABS "/var/spool/cron/crontabs" +#endif +#ifndef TMPDIR +#define TMPDIR "/var/spool/cron" +#endif +#ifndef CRONUPDATE +#define CRONUPDATE "cron.update" +#endif +#ifndef PATH_VI +#define PATH_VI "/usr/bin/vi" /* location of vi */ +#endif + +#include "busybox.h" + +static const char *CDir = CRONTABS; + +static void EditFile(const char *user, const char *file); +static int GetReplaceStream(const char *user, const char *file); +static int ChangeUser(const char *user, short dochdir); + +int +crontab_main(int ac, char **av) +{ + enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE; + const struct passwd *pas; + const char *repFile = NULL; + int repFd = 0; + int i; + char caller[256]; /* user that ran program */ + int UserId; + + UserId = getuid(); + if ((pas = getpwuid(UserId)) == NULL) + perror_msg_and_die("getpwuid"); + + strncpy(caller, pas->pw_name, sizeof(caller)); + + i = 1; + if (ac > 1) { + if (av[1][0] == '-' && av[1][1] == 0) { + option = REPLACE; + ++i; + } else if (av[1][0] != '-') { + option = REPLACE; + ++i; + repFile = av[1]; + } + } + + for (; i < ac; ++i) { + char *ptr = av[i]; + + if (*ptr != '-') + break; + ptr += 2; + + switch(ptr[-1]) { + case 'l': + if (ptr[-1] == 'l') + option = LIST; + /* fall through */ + case 'e': + if (ptr[-1] == 'e') + option = EDIT; + /* fall through */ + case 'd': + if (ptr[-1] == 'd') + option = DELETE; + /* fall through */ + case 'u': + if (i + 1 < ac && av[i+1][0] != '-') { + ++i; + if (getuid() == geteuid()) { + pas = getpwnam(av[i]); + if (pas) { + UserId = pas->pw_uid; + } else { + error_msg_and_die("user %s unknown", av[i]); + } + } else { + error_msg_and_die("only the superuser may specify a user"); + } + } + break; + case 'c': + if (getuid() == geteuid()) { + CDir = (*ptr) ? ptr : av[++i]; + } else { + error_msg_and_die("-c option: superuser only"); + } + break; + default: + i = ac; + break; + } + } + if (i != ac || option == NONE) + show_usage(); + + /* + * Get password entry + */ + + if ((pas = getpwuid(UserId)) == NULL) + perror_msg_and_die("getpwuid"); + + /* + * If there is a replacement file, obtain a secure descriptor to it. + */ + + if (repFile) { + repFd = GetReplaceStream(caller, repFile); + if (repFd < 0) + error_msg_and_die("unable to read replacement file"); + } + + /* + * Change directory to our crontab directory + */ + + if (chdir(CDir) < 0) + perror_msg_and_die("cannot change dir to %s", CDir); + + /* + * Handle options as appropriate + */ + + switch(option) { + case LIST: + { + FILE *fi; + char buf[1024]; + + if ((fi = fopen(pas->pw_name, "r"))) { + while (fgets(buf, sizeof(buf), fi) != NULL) + fputs(buf, stdout); + fclose(fi); + } else { + error_msg("no crontab for %s", pas->pw_name); + } + } + break; + case EDIT: + { + FILE *fi; + int fd; + int n; + char tmp[128]; + char buf[1024]; + + snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid()); + if ((fd = open(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600)) >= 0) { + chown(tmp, getuid(), getgid()); + if ((fi = fopen(pas->pw_name, "r"))) { + while ((n = fread(buf, 1, sizeof(buf), fi)) > 0) + write(fd, buf, n); + } + EditFile(caller, tmp); + remove(tmp); + lseek(fd, 0L, 0); + repFd = fd; + } else { + error_msg_and_die("unable to create %s", tmp); + } + + } + option = REPLACE; + /* fall through */ + case REPLACE: + { + char buf[1024]; + char path[1024]; + int fd; + int n; + + snprintf(path, sizeof(path), "%s.new", pas->pw_name); + if ((fd = open(path, O_CREAT|O_TRUNC|O_EXCL|O_APPEND|O_WRONLY, 0600)) >= 0) { + while ((n = read(repFd, buf, sizeof(buf))) > 0) { + write(fd, buf, n); + } + close(fd); + rename(path, pas->pw_name); + } else { + error_msg("unable to create %s/%s", CDir, buf); + } + close(repFd); + } + break; + case DELETE: + remove(pas->pw_name); + break; + case NONE: + default: + break; + } + + /* + * Bump notification file. Handle window where crond picks file up + * before we can write our entry out. + */ + + if (option == REPLACE || option == DELETE) { + FILE *fo; + struct stat st; + + while ((fo = fopen(CRONUPDATE, "a"))) { + fprintf(fo, "%s\n", pas->pw_name); + fflush(fo); + if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) { + fclose(fo); + break; + } + fclose(fo); + /* loop */ + } + if (fo == NULL) { + error_msg("unable to append to %s/%s", CDir, CRONUPDATE); + } + } + return 0; +} + +static int +GetReplaceStream(const char *user, const char *file) +{ + int filedes[2]; + int pid; + int fd; + int n; + char buf[1024]; + + if (pipe(filedes) < 0) { + perror("pipe"); + return(-1); + } + if ((pid = fork()) < 0) { + perror("fork"); + return(-1); + } + if (pid > 0) { + /* + * PARENT + */ + + close(filedes[1]); + if (read(filedes[0], buf, 1) != 1) { + close(filedes[0]); + filedes[0] = -1; + } + return(filedes[0]); + } + + /* + * CHILD + */ + + close(filedes[0]); + + if (ChangeUser(user, 0) < 0) + exit(0); + + fd = open(file, O_RDONLY); + if (fd < 0) { + error_msg("unable to open %s", file); + exit(0); + } + buf[0] = 0; + write(filedes[1], buf, 1); + while ((n = read(fd, buf, sizeof(buf))) > 0) { + write(filedes[1], buf, n); + } + exit(0); +} + +static void +EditFile(const char *user, const char *file) +{ + int pid; + + if ((pid = fork()) == 0) { + /* + * CHILD - change user and run editor + */ + char *ptr; + char visual[1024]; + + if (ChangeUser(user, 1) < 0) + exit(0); + if ((ptr = getenv("VISUAL")) == NULL || strlen(ptr) > 256) + ptr = PATH_VI; + + snprintf(visual, sizeof(visual), "%s %s", ptr, file); + execl("/bin/sh", "/bin/sh", "-c", visual, NULL); + perror("exec"); + exit(0); + } + if (pid < 0) { + /* + * PARENT - failure + */ + perror_msg_and_die("fork"); + } + wait4(pid, NULL, 0, NULL); +} + +static void +log(const char *ctl, ...) +{ + va_list va; + char buf[1024]; + + va_start(va, ctl); + vsnprintf(buf, sizeof(buf), ctl, va); + syslog(LOG_NOTICE, "%s",buf ); + va_end(va); +} + +static int +ChangeUser(const char *user, short dochdir) +{ + struct passwd *pas; + + /* + * Obtain password entry and change privilages + */ + + if ((pas = getpwnam(user)) == 0) { + log("failed to get uid for %s", user); + return(-1); + } + setenv("USER", pas->pw_name, 1); + setenv("HOME", pas->pw_dir, 1); + setenv("SHELL", "/bin/sh", 1); + + /* + * Change running state to the user in question + */ + + if (initgroups(user, pas->pw_gid) < 0) { + log("initgroups failed: %s %m", user); + return(-1); + } + if (setregid(pas->pw_gid, pas->pw_gid) < 0) { + log("setregid failed: %s %d", user, pas->pw_gid); + return(-1); + } + if (setreuid(pas->pw_uid, pas->pw_uid) < 0) { + log("setreuid failed: %s %d", user, pas->pw_uid); + return(-1); + } + if (dochdir) { + if (chdir(pas->pw_dir) < 0) { + if (chdir(TMPDIR) < 0) { + log("chdir failed: %s %s", user, pas->pw_dir); + log("chdir failed: %s " TMPDIR, user); + return(-1); + } + } + } + return(pas->pw_uid); +} -- cgit v1.2.3