From 554dde8e9a2e1e8bdf2816f04af985b227937c32 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 18 Aug 2006 02:27:16 +0200 Subject: [PATCH] db: store devpath - node relationship for all devices If we don't have any interesting values to store, we just use a symlink (doesn't occupy a whole page on tmpfs like a file) to store the name of the node belonging to a devpath. This will allow udevinfo to resolve all names, even when we don't have a full database entry. --- udev_db.c | 117 +++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 85 insertions(+), 32 deletions(-) diff --git a/udev_db.c b/udev_db.c index e9ae79913..b058351d2 100644 --- a/udev_db.c +++ b/udev_db.c @@ -70,49 +70,55 @@ static int db_file_to_devpath(const char *filename, char *devpath, size_t len) int udev_db_add_device(struct udevice *udev) { char filename[PATH_SIZE]; - struct name_entry *name_loop; - FILE *f; if (udev->test_run) return 0; - /* don't write anything if udev created only the node with the - * kernel name without any interesting data to remember + devpath_to_db_path(udev->dev->devpath, filename, sizeof(filename)); + create_path(filename); + + /* + * create only a symlink with the name as the target + * if we don't have any interesting data to remember */ if (strcmp(udev->name, udev->dev->kernel_name) == 0 && list_empty(&udev->symlink_list) && list_empty(&udev->env_list) && !udev->partitions && !udev->ignore_remove) { - dbg("nothing interesting to store in udevdb, skip"); - goto exit; - } - - devpath_to_db_path(udev->dev->devpath, filename, sizeof(filename)); - create_path(filename); - f = fopen(filename, "w"); - if (f == NULL) { - err("unable to create db file '%s': %s", filename, strerror(errno)); - return -1; + dbg("nothing interesting to store, create symlink"); + unlink(filename); + if (symlink(udev->name, filename) != 0) { + err("unable to create db link '%s': %s", filename, strerror(errno)); + return -1; + } + } else { + struct name_entry *name_loop; + FILE *f; + + f = fopen(filename, "w"); + if (f == NULL) { + err("unable to create db file '%s': %s", filename, strerror(errno)); + return -1; + } + dbg("storing data for device '%s' in '%s'", udev->dev->devpath, filename); + + fprintf(f, "N:%s\n", udev->name); + list_for_each_entry(name_loop, &udev->symlink_list, node) + fprintf(f, "S:%s\n", name_loop->name); + fprintf(f, "M:%u:%u\n", major(udev->devt), minor(udev->devt)); + if (udev->partitions) + fprintf(f, "A:%u\n", udev->partitions); + if (udev->ignore_remove) + fprintf(f, "R:%u\n", udev->ignore_remove); + list_for_each_entry(name_loop, &udev->env_list, node) + fprintf(f, "E:%s\n", name_loop->name); + fclose(f); } - dbg("storing data for device '%s' in '%s'", udev->dev->devpath, filename); - - fprintf(f, "N:%s\n", udev->name); - list_for_each_entry(name_loop, &udev->symlink_list, node) - fprintf(f, "S:%s\n", name_loop->name); - fprintf(f, "M:%u:%u\n", major(udev->devt), minor(udev->devt)); - if (udev->partitions) - fprintf(f, "A:%u\n", udev->partitions); - if (udev->ignore_remove) - fprintf(f, "R:%u\n", udev->ignore_remove); - list_for_each_entry(name_loop, &udev->env_list, node) - fprintf(f, "E:%s\n", name_loop->name); - fclose(f); - -exit: return 0; } int udev_db_get_device(struct udevice *udev, const char *devpath) { + struct stat stats; char filename[PATH_SIZE]; char line[PATH_SIZE]; unsigned int major, minor; @@ -122,13 +128,35 @@ int udev_db_get_device(struct udevice *udev, const char *devpath) size_t cur; size_t count; + strlcpy(udev->dev->devpath, devpath, sizeof(udev->dev->devpath)); devpath_to_db_path(devpath, filename, sizeof(filename)); - if (file_map(filename, &buf, &bufsize) != 0) { + + if (lstat(filename, &stats) != 0) { info("no db file to read %s: %s", filename, strerror(errno)); return -1; } + if ((stats.st_mode & S_IFMT) == S_IFLNK) { + char target[NAME_SIZE]; + int target_len; + + info("found a symlink as db file"); + target_len = readlink(filename, target, sizeof(target)); + if (target_len > 0) + target[target_len] = '\0'; + else { + info("error reading db link %s: %s", filename, strerror(errno)); + return -1; + } + dbg("db link points to '%s'", target); + strlcpy(udev->name, target, sizeof(udev->name)); + return 0; + } + + if (file_map(filename, &buf, &bufsize) != 0) { + info("error reading db file %s: %s", filename, strerror(errno)); + return -1; + } - strlcpy(udev->dev->devpath, devpath, sizeof(udev->dev->devpath)); cur = 0; while (cur < bufsize) { count = buf_get_line(buf, bufsize, cur); @@ -216,6 +244,7 @@ int udev_db_lookup_name(const char *name, char *devpath, size_t len) struct dirent *ent; char filename[PATH_SIZE]; char nodename[PATH_SIZE]; + struct stat stats; char *bufline; char *buf; size_t bufsize; @@ -232,8 +261,32 @@ int udev_db_lookup_name(const char *name, char *devpath, size_t len) filename[sizeof(filename)-1] = '\0'; dbg("looking at '%s'", filename); + if (lstat(filename, &stats) != 0) { + info("unable to read %s: %s", filename, strerror(errno)); + continue; + } + if ((stats.st_mode & S_IFMT) == S_IFLNK) { + char target[NAME_SIZE]; + int target_len; + + info("found a symlink as db file"); + target_len = readlink(filename, target, sizeof(target)); + if (target_len > 0) + target[target_len] = '\0'; + else { + info("error reading db link %s: %s", filename, strerror(errno)); + return -1; + } + dbg("db link points to '%s'", target); + if (strcmp(name, target) == 0) { + db_file_to_devpath(ent->d_name, devpath, len); + found =1; + } + continue; + } + if (file_map(filename, &buf, &bufsize) != 0) { - err("unable to read db file '%s': %s", filename, strerror(errno)); + info("unable to read db file '%s': %s", filename, strerror(errno)); continue; } -- 2.30.2