From cf26ab70c11416401cd53e6a6a5fb4d5c2583246 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Thu, 27 Mar 2008 22:45:44 +0000 Subject: mdev: plug a few memory and fd leaks; simplify code a bit --- util-linux/mdev.c | 140 +++++++++++++++++++++++++++--------------------------- 1 file changed, 69 insertions(+), 71 deletions(-) (limited to 'util-linux') diff --git a/util-linux/mdev.c b/util-linux/mdev.c index 5a8f1d918..f86ce14ce 100644 --- a/util-linux/mdev.c +++ b/util-linux/mdev.c @@ -21,7 +21,11 @@ struct globals { #define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */ +/* We use additional 64+ bytes in make_device() */ +#define SCRATCH_SIZE 80 + /* mknod in /dev based on a path like "/sys/block/hda/hda1" */ +/* NB: "mdev -s" may call us many times, do not leak memory/fds! */ static void make_device(char *path, int delete) { const char *device_name; @@ -29,7 +33,7 @@ static void make_device(char *path, int delete) int mode = 0660; uid_t uid = 0; gid_t gid = 0; - char *temp = path + strlen(path); + char *dev_maj_min = path + strlen(path); char *command = NULL; char *alias = NULL; @@ -42,21 +46,20 @@ static void make_device(char *path, int delete) * also depend on path having writeable space after it. */ if (!delete) { - strcat(path, "/dev"); - len = open_read_close(path, temp + 1, 64); - *temp++ = 0; + strcpy(dev_maj_min, "/dev"); + len = open_read_close(path, dev_maj_min + 1, 64); + *dev_maj_min++ = '\0'; if (len < 1) { - if (ENABLE_FEATURE_MDEV_EXEC) - /* no "dev" file, so just try to run script */ - *temp = 0; - else + if (!ENABLE_FEATURE_MDEV_EXEC) return; + /* no "dev" file, so just try to run script */ + *dev_maj_min = '\0'; } } /* Determine device name, type, major and minor */ device_name = bb_basename(path); - type = (path[5] == 'c' ? S_IFCHR : S_IFBLK); + type = (path[5] == 'c' ? S_IFCHR : S_IFBLK); /* "/sys/[c]lass"? */ if (ENABLE_FEATURE_MDEV_CONF) { FILE *fp; @@ -70,15 +73,18 @@ static void make_device(char *path, int delete) while ((vline = line = xmalloc_fgetline(fp)) != NULL) { int field; - - /* A pristine copy for command execution. */ char *orig_line; + if (ENABLE_FEATURE_MDEV_EXEC) - orig_line = xstrdup(line); + orig_line = xstrdup(line); /* pristine copy for command execution. */ ++lineno; - /* Three fields: regex, uid:gid, mode */ +// TODO: get rid of loop, +// just linear skip_whitespace() style code will do! +// (will also get rid of orig_line). + + /* Fields: regex uid:gid mode [alias] [cmd] */ for (field = 0; field < (3 + ENABLE_FEATURE_MDEV_RENAME + ENABLE_FEATURE_MDEV_EXEC); ++field) { /* Find a non-empty field */ @@ -117,9 +123,9 @@ static void make_device(char *path, int delete) struct group *grp; char *str_uid = val; - char *str_gid = strchr(val, ':'); - if (str_gid) - *str_gid = '\0', ++str_gid; + char *str_gid = strchrnul(val, ':'); + if (*str_gid) + *str_gid++ = '\0'; /* Parse UID */ pass = getpwnam(str_uid); @@ -128,7 +134,7 @@ static void make_device(char *path, int delete) else uid = strtoul(str_uid, NULL, 10); - /* parse GID */ + /* Parse GID */ grp = getgrnam(str_gid); if (grp) gid = grp->gr_gid; @@ -144,8 +150,10 @@ static void make_device(char *path, int delete) if (*val != '>') ++field; - else + else { + free(alias); /* don't leak in case we matched it on prev line */ alias = xstrdup(val + 1); + } } @@ -162,12 +170,17 @@ static void make_device(char *path, int delete) } /* Correlate the position in the "@$*" with the delete - * step so that we get the proper behavior. + * step so that we get the proper behavior: + * @cmd: run on create + * $cmd: run on delete + * *cmd: run on both */ - if ((s2 - s + 1) & (1 << delete)) + if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) { + free(command); /* don't leak in case we matched it on prev line */ command = xstrdup(orig_line + (val + 1 - line)); + } } - } + } /* end of "for every field" */ /* Did everything parse happily? */ if (field <= 2) @@ -177,21 +190,13 @@ static void make_device(char *path, int delete) free(line); if (ENABLE_FEATURE_MDEV_EXEC) free(orig_line); - } - - if (ENABLE_FEATURE_CLEAN_UP) - fclose(fp); + } /* end of "while line is read from /etc/mdev.conf" */ - end_parse: /* nothing */ ; + fclose(fp); } + end_parse: - if (!delete) { - if (sscanf(temp, "%d:%d", &major, &minor) != 2) { - if (ENABLE_FEATURE_MDEV_EXEC) - goto skip_creation; - else - return; - } + if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) { if (ENABLE_FEATURE_MDEV_RENAME) unlink(device_name); @@ -208,39 +213,39 @@ static void make_device(char *path, int delete) if (ENABLE_FEATURE_MDEV_RENAME && alias) { char *dest; - temp = strrchr(alias, '/'); - if (temp) { - if (temp[1] != '\0') + dest = strrchr(alias, '/'); + if (dest) { + if (dest[1] != '\0') /* given a file name, so rename it */ - *temp = '\0'; + *dest = '\0'; bb_make_directory(alias, 0755, FILEUTILS_RECUR); dest = concat_path_file(alias, device_name); + free(alias); } else dest = alias; - rename(device_name, dest); // TODO: xrename? + rename(device_name, dest); symlink(dest, device_name); - if (alias != dest) - free(alias); free(dest); } } - skip_creation: /* nothing */ ; } + if (ENABLE_FEATURE_MDEV_EXEC && command) { - /* setenv will leak memory, so use putenv */ + /* setenv will leak memory, use putenv/unsetenv/free */ char *s = xasprintf("MDEV=%s", device_name); putenv(s); if (system(command) == -1) - bb_perror_msg_and_die("cannot run %s", command); + bb_perror_msg_and_die("can't run '%s'", command); s[4] = '\0'; unsetenv(s); free(s); free(command); } + if (delete) - remove_file(device_name, FILEUTILS_FORCE); + unlink(device_name); } /* File callback for /sys/ traversal */ @@ -249,14 +254,15 @@ static int fileAction(const char *fileName, void *userData, int depth ATTRIBUTE_UNUSED) { - size_t len = strlen(fileName) - 4; + size_t len = strlen(fileName) - 4; /* can't underflow */ char *scratch = userData; - if (strcmp(fileName + len, "/dev")) + /* len check is for paranoid reasons */ + if (strcmp(fileName + len, "/dev") || len >= PATH_MAX) return FALSE; strcpy(scratch, fileName); - scratch[len] = 0; + scratch[len] = '\0'; make_device(scratch, 0); return TRUE; @@ -287,12 +293,6 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa int cnt; int firmware_fd, loading_fd, data_fd; - /* check for $FIRMWARE from kernel */ - /* XXX: dont bother: open(NULL) works same as open("no-such-file") - * if (!firmware) - * return; - */ - /* check for /lib/firmware/$FIRMWARE */ xchdir("/lib/firmware"); firmware_fd = xopen(firmware, O_RDONLY); @@ -304,16 +304,15 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa xchdir(sysfs_path); for (cnt = 0; cnt < 30; ++cnt) { loading_fd = open("loading", O_WRONLY); - if (loading_fd == -1) - sleep(1); - else - break; + if (loading_fd != -1) + goto loading; + sleep(1); } - if (loading_fd == -1) - goto out; + goto out; + loading: /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */ - if (write(loading_fd, "1", 1) != 1) + if (full_write(loading_fd, "1", 1) != 1) goto out; /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */ @@ -324,9 +323,9 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */ if (cnt > 0) - write(loading_fd, "0", 1); + full_write(loading_fd, "0", 1); else - write(loading_fd, "-1", 2); + full_write(loading_fd, "-1", 2); out: if (ENABLE_FEATURE_CLEAN_UP) { @@ -341,16 +340,14 @@ int mdev_main(int argc, char **argv) { char *action; char *env_path; - RESERVE_CONFIG_BUFFER(temp,PATH_MAX); + RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE); xchdir("/dev"); - if (argc == 2 && !strcmp(argv[1],"-s")) { - + if (argc == 2 && !strcmp(argv[1], "-s")) { /* Scan: * mdev -s */ - struct stat st; xstat("/", &st); @@ -366,26 +363,27 @@ int mdev_main(int argc, char **argv) fileAction, dirAction, temp, 0); } else { - /* Hotplug: * env ACTION=... DEVPATH=... mdev * ACTION can be "add" or "remove" * DEVPATH is like "/block/sda" or "/class/input/mice" */ - action = getenv("ACTION"); env_path = getenv("DEVPATH"); if (!action || !env_path) bb_show_usage(); - sprintf(temp, "/sys%s", env_path); + snprintf(temp, PATH_MAX, "/sys%s", env_path); if (!strcmp(action, "remove")) make_device(temp, 1); else if (!strcmp(action, "add")) { make_device(temp, 0); - if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) - load_firmware(getenv("FIRMWARE"), temp); + if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) { + char *fw = getenv("FIRMWARE"); + if (fw) + load_firmware(fw, temp); + } } } -- cgit v1.2.3