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bash loadable builtin to set proctitle (ps -ocmd) on linux [VERY HACKY]
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| #include <errno.h> | |
| #include <string.h> | |
| #include <fcntl.h> | |
| #include <unistd.h> | |
| #include <bash/builtins.h> | |
| #include <bash/shell.h> | |
| #include <bash/builtins/bashgetopt.h> | |
| #include <bash/builtins/common.h> | |
| static char *memstart = NULL; | |
| static char *memend = NULL; | |
| static char *memstart_copy = NULL; | |
| static char *original_shell_name = NULL; | |
| static size_t | |
| count_bytes(char const *const path) | |
| { | |
| size_t size = 0; | |
| int fd; | |
| do { | |
| fd = open(path, O_RDONLY); | |
| } while (fd < 0 && errno == EINTR); | |
| if (fd < 0) { | |
| builtin_warning("%s: Open error: %s", path, strerror(errno)); | |
| return size; | |
| } | |
| ssize_t nread; | |
| do { | |
| char buf[PIPE_BUF]; | |
| nread = read(fd, buf, sizeof buf / sizeof *buf); | |
| if (nread > 0) | |
| size += nread; | |
| } while (nread > 0 || (nread != 0 && errno == EINTR)); | |
| if (nread < 0) | |
| builtin_warning("%s: Read error: %s", path, strerror(errno)); | |
| int ret; | |
| do { | |
| ret = close(fd); | |
| } while (ret < 0 && errno == EINTR); | |
| if (ret < 0) | |
| builtin_warning("%s: Close error: %s", path, strerror(errno)); | |
| return size; | |
| } | |
| int | |
| setproctitle_builtin_load(char const *const name) | |
| { | |
| (void)name; | |
| /* shell_name is always an offset into argv[0] */ | |
| memstart = shell_name; | |
| /* find the start of argv[0]; linux seems fine with this approach */ | |
| while (memstart[-1]) | |
| --memstart; | |
| /* save and copy shell_name to the heap */ | |
| memstart_copy = savestring(memstart); | |
| original_shell_name = shell_name; | |
| shell_name = &memstart_copy[shell_name - memstart]; | |
| /* figure out size of usable memory counting bytes in | |
| /proc/self/cmdline and /proc/self/environ */ | |
| memend = memstart; | |
| memend += count_bytes("/proc/self/cmdline"); | |
| memend += count_bytes("/proc/self/environ"); | |
| /* fallback to length of argv[0] in case that does not work... */ | |
| if (memend == memstart) | |
| memend += strlen(memstart) + 1; | |
| return 1; | |
| } | |
| void | |
| setproctitle_builtin_unload(char const *const name) | |
| { | |
| (void)name; | |
| /* restore shell_name */ | |
| (void)strcpy(memstart, memstart_copy); | |
| shell_name = original_shell_name; | |
| xfree(memstart_copy); | |
| } | |
| static int | |
| setproctitle_builtin(WORD_LIST *list) | |
| { | |
| if (no_options(list)) | |
| return EX_USAGE; | |
| list = loptend; | |
| (void)memset(memstart, 0, memend - memstart); | |
| char *memused = memstart; | |
| for (WORD_LIST const *l = list; l; l = l->next) { | |
| size_t const maxlen = memend - memused - 1; | |
| char const *const arg = l->word->word; | |
| size_t const len = strlen(arg); | |
| if (len > maxlen) { | |
| builtin_warning("Too long, trimming..."); | |
| (void)memcpy(memused, arg, maxlen); | |
| break; | |
| } | |
| (void)memcpy(memused, arg, len); | |
| memused += len; | |
| } | |
| return EXECUTION_SUCCESS; | |
| } | |
| static char *setproctitle_doc[] = { | |
| "Changes the shell's proctitle", | |
| "", | |
| "If multiple arguments are passed, they are concatenated.", | |
| "", | |
| "Exit Status:", | |
| "Always returns 0 if the command is valid.", | |
| NULL, | |
| }; | |
| struct builtin setproctitle_struct = { | |
| "setproctitle", | |
| setproctitle_builtin, | |
| BUILTIN_ENABLED, | |
| setproctitle_doc, | |
| "setproctitle [title ...]", | |
| 0, | |
| }; |
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