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v3.6.3
lib/sysfs.c
480 строк
11 KB
Martin Mares
Sysfs: fixed sysfs_deref_link()
12 июл 2018, 14:59
12 июл 2018, 14:59
f15db37
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/* * The PCI Library -- Configuration Access via /sys/bus/pci * * Copyright (c) 2003 Matthew Wilcox <matthew@wil.cx> * Copyright (c) 1997--2008 Martin Mares <mj@ucw.cz> * * Can be freely distributed and used under the terms of the GNU GPL. */ #define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdarg.h> #include <unistd.h> #include <errno.h> #include <dirent.h> #include <fcntl.h> #include <sys/types.h> #include "internal.h" #include "pread.h" static void sysfs_config(struct pci_access *a) { pci_define_param(a, "sysfs.path", PCI_PATH_SYS_BUS_PCI, "Path to the sysfs device tree"); } static inline char * sysfs_name(struct pci_access *a) { return pci_get_param(a, "sysfs.path"); } static int sysfs_detect(struct pci_access *a) { if (access(sysfs_name(a), R_OK)) { a->debug("...cannot open %s", sysfs_name(a)); return 0; } a->debug("...using %s", sysfs_name(a)); return 1; } static void sysfs_init(struct pci_access *a) { a->fd = -1; a->fd_vpd = -1; } static void sysfs_flush_cache(struct pci_access *a) { if (a->fd >= 0) { close(a->fd); a->fd = -1; } if (a->fd_vpd >= 0) { close(a->fd_vpd); a->fd_vpd = -1; } a->cached_dev = NULL; } static void sysfs_cleanup(struct pci_access *a) { sysfs_flush_cache(a); } #define OBJNAMELEN 1024 static void sysfs_obj_name(struct pci_dev *d, char *object, char *buf) { int n = snprintf(buf, OBJNAMELEN, "%s/devices/%04x:%02x:%02x.%d/%s", sysfs_name(d->access), d->domain, d->bus, d->dev, d->func, object); if (n < 0 || n >= OBJNAMELEN) d->access->error("File name too long"); } #define OBJBUFSIZE 1024 static int sysfs_get_string(struct pci_dev *d, char *object, char *buf, int mandatory) { struct pci_access *a = d->access; int fd, n; char namebuf[OBJNAMELEN]; void (*warn)(char *msg, ...) = (mandatory ? a->error : a->warning); sysfs_obj_name(d, object, namebuf); fd = open(namebuf, O_RDONLY); if (fd < 0) { if (mandatory || errno != ENOENT) warn("Cannot open %s: %s", namebuf, strerror(errno)); return 0; } n = read(fd, buf, OBJBUFSIZE); close(fd); if (n < 0) { warn("Error reading %s: %s", namebuf, strerror(errno)); return 0; } if (n >= OBJBUFSIZE) { warn("Value in %s too long", namebuf); return 0; } buf[n] = 0; return 1; } static char * sysfs_deref_link(struct pci_dev *d, char *link_name) { char path[2*OBJNAMELEN], rel_path[OBJNAMELEN]; sysfs_obj_name(d, link_name, path); memset(rel_path, 0, sizeof(rel_path)); if (readlink(path, rel_path, sizeof(rel_path)) < 0) return NULL; sysfs_obj_name(d, "", path); strcat(path, rel_path); // Returns a pointer to malloc'ed memory return realpath(path, NULL); } static int sysfs_get_value(struct pci_dev *d, char *object, int mandatory) { char buf[OBJBUFSIZE]; if (sysfs_get_string(d, object, buf, mandatory)) return strtol(buf, NULL, 0); else return -1; } static void sysfs_get_resources(struct pci_dev *d) { struct pci_access *a = d->access; char namebuf[OBJNAMELEN], buf[256]; FILE *file; int i; sysfs_obj_name(d, "resource", namebuf); file = fopen(namebuf, "r"); if (!file) a->error("Cannot open %s: %s", namebuf, strerror(errno)); for (i = 0; i < 7; i++) { unsigned long long start, end, size, flags; if (!fgets(buf, sizeof(buf), file)) break; if (sscanf(buf, "%llx %llx %llx", &start, &end, &flags) != 3) a->error("Syntax error in %s", namebuf); if (end > start) size = end - start + 1; else size = 0; if (i < 6) { d->flags[i] = flags; flags &= PCI_ADDR_FLAG_MASK; d->base_addr[i] = start | flags; d->size[i] = size; } else { d->rom_flags = flags; flags &= PCI_ADDR_FLAG_MASK; d->rom_base_addr = start | flags; d->rom_size = size; } } fclose(file); } static void sysfs_scan(struct pci_access *a) { char dirname[1024]; DIR *dir; struct dirent *entry; int n; n = snprintf(dirname, sizeof(dirname), "%s/devices", sysfs_name(a)); if (n < 0 || n >= (int) sizeof(dirname)) a->error("Directory name too long"); dir = opendir(dirname); if (!dir) a->error("Cannot open %s", dirname); while ((entry = readdir(dir))) { struct pci_dev *d; unsigned int dom, bus, dev, func; /* ".", ".." or a special non-device perhaps */ if (entry->d_name[0] == '.') continue; d = pci_alloc_dev(a); if (sscanf(entry->d_name, "%x:%x:%x.%d", &dom, &bus, &dev, &func) < 4) a->error("sysfs_scan: Couldn't parse entry name %s", entry->d_name); /* Ensure kernel provided domain that fits in a signed integer */ if (dom > 0x7fffffff) a->error("sysfs_scan: Invalid domain %x", dom); d->domain = dom; d->bus = bus; d->dev = dev; d->func = func; if (!a->buscentric) { sysfs_get_resources(d); d->irq = sysfs_get_value(d, "irq", 1); /* * We could read these faster from the config registers, but we want to give * the kernel a chance to fix up ID's and especially classes of broken devices. */ d->vendor_id = sysfs_get_value(d, "vendor", 1); d->device_id = sysfs_get_value(d, "device", 1); d->device_class = sysfs_get_value(d, "class", 1) >> 8; d->known_fields = PCI_FILL_IDENT | PCI_FILL_CLASS | PCI_FILL_IRQ | PCI_FILL_BASES | PCI_FILL_ROM_BASE | PCI_FILL_SIZES | PCI_FILL_IO_FLAGS; } pci_link_dev(a, d); } closedir(dir); } static void sysfs_fill_slots(struct pci_access *a) { char dirname[1024]; DIR *dir; struct dirent *entry; int n; n = snprintf(dirname, sizeof(dirname), "%s/slots", sysfs_name(a)); if (n < 0 || n >= (int) sizeof(dirname)) a->error("Directory name too long"); dir = opendir(dirname); if (!dir) return; while (entry = readdir(dir)) { char namebuf[OBJNAMELEN], buf[16]; FILE *file; unsigned int dom, bus, dev; int res = 0; struct pci_dev *d; /* ".", ".." or a special non-device perhaps */ if (entry->d_name[0] == '.') continue; n = snprintf(namebuf, OBJNAMELEN, "%s/%s/%s", dirname, entry->d_name, "address"); if (n < 0 || n >= OBJNAMELEN) a->error("File name too long"); file = fopen(namebuf, "r"); /* * Old versions of Linux had a fakephp which didn't have an 'address' * file. There's no useful information to be gleaned from these * devices, pretend they're not there. */ if (!file) continue; if (!fgets(buf, sizeof(buf), file) || (res = sscanf(buf, "%x:%x:%x", &dom, &bus, &dev)) < 3) { /* * In some cases, the slot is not tied to a specific device before * a card gets inserted. This happens for example on IBM pSeries * and we need not warn about it. */ if (res != 2) a->warning("sysfs_fill_slots: Couldn't parse entry address %s", buf); } else { for (d = a->devices; d; d = d->next) if (dom == (unsigned)d->domain && bus == d->bus && dev == d->dev && !d->phy_slot) d->phy_slot = pci_set_property(d, PCI_FILL_PHYS_SLOT, entry->d_name); } fclose(file); } closedir(dir); } static int sysfs_fill_info(struct pci_dev *d, int flags) { if ((flags & PCI_FILL_PHYS_SLOT) && !(d->known_fields & PCI_FILL_PHYS_SLOT)) { struct pci_dev *pd; sysfs_fill_slots(d->access); for (pd = d->access->devices; pd; pd = pd->next) pd->known_fields |= PCI_FILL_PHYS_SLOT; } if ((flags & PCI_FILL_MODULE_ALIAS) && !(d->known_fields & PCI_FILL_MODULE_ALIAS)) { char buf[OBJBUFSIZE]; if (sysfs_get_string(d, "modalias", buf, 0)) d->module_alias = pci_set_property(d, PCI_FILL_MODULE_ALIAS, buf); } if ((flags & PCI_FILL_LABEL) && !(d->known_fields & PCI_FILL_LABEL)) { char buf[OBJBUFSIZE]; if (sysfs_get_string(d, "label", buf, 0)) d->label = pci_set_property(d, PCI_FILL_LABEL, buf); } if ((flags & PCI_FILL_NUMA_NODE) && !(d->known_fields & PCI_FILL_NUMA_NODE)) d->numa_node = sysfs_get_value(d, "numa_node", 0); if ((flags & PCI_FILL_DT_NODE) && !(d->known_fields & PCI_FILL_DT_NODE)) { char *node = sysfs_deref_link(d, "of_node"); if (node) { pci_set_property(d, PCI_FILL_DT_NODE, node); free(node); } } return pci_generic_fill_info(d, flags); } /* Intent of the sysfs_setup() caller */ enum { SETUP_READ_CONFIG = 0, SETUP_WRITE_CONFIG = 1, SETUP_READ_VPD = 2 }; static int sysfs_setup(struct pci_dev *d, int intent) { struct pci_access *a = d->access; char namebuf[OBJNAMELEN]; if (a->cached_dev != d || (intent == SETUP_WRITE_CONFIG && !a->fd_rw)) { sysfs_flush_cache(a); a->cached_dev = d; } if (intent == SETUP_READ_VPD) { if (a->fd_vpd < 0) { sysfs_obj_name(d, "vpd", namebuf); a->fd_vpd = open(namebuf, O_RDONLY); /* No warning on error; vpd may be absent or accessible only to root */ } return a->fd_vpd; } if (a->fd < 0) { sysfs_obj_name(d, "config", namebuf); a->fd_rw = a->writeable || intent == SETUP_WRITE_CONFIG; a->fd = open(namebuf, a->fd_rw ? O_RDWR : O_RDONLY); if (a->fd < 0) a->warning("Cannot open %s", namebuf); a->fd_pos = 0; } return a->fd; } static int sysfs_read(struct pci_dev *d, int pos, byte *buf, int len) { int fd = sysfs_setup(d, SETUP_READ_CONFIG); int res; if (fd < 0) return 0; res = do_read(d, fd, buf, len, pos); if (res < 0) { d->access->warning("sysfs_read: read failed: %s", strerror(errno)); return 0; } else if (res != len) return 0; return 1; } static int sysfs_write(struct pci_dev *d, int pos, byte *buf, int len) { int fd = sysfs_setup(d, SETUP_WRITE_CONFIG); int res; if (fd < 0) return 0; res = do_write(d, fd, buf, len, pos); if (res < 0) { d->access->warning("sysfs_write: write failed: %s", strerror(errno)); return 0; } else if (res != len) { d->access->warning("sysfs_write: tried to write %d bytes at %d, but only %d succeeded", len, pos, res); return 0; } return 1; } #ifdef PCI_HAVE_DO_READ /* pread() is not available and do_read() only works for a single fd, so we * cannot implement read_vpd properly. */ static int sysfs_read_vpd(struct pci_dev *d, int pos, byte *buf, int len) { return 0; } #else /* !PCI_HAVE_DO_READ */ static int sysfs_read_vpd(struct pci_dev *d, int pos, byte *buf, int len) { int fd = sysfs_setup(d, SETUP_READ_VPD); int res; if (fd < 0) return 0; res = pread(fd, buf, len, pos); if (res < 0) { d->access->warning("sysfs_read_vpd: read failed: %s", strerror(errno)); return 0; } else if (res != len) return 0; return 1; } #endif /* PCI_HAVE_DO_READ */ static void sysfs_cleanup_dev(struct pci_dev *d) { struct pci_access *a = d->access; if (a->cached_dev == d) sysfs_flush_cache(a); } struct pci_methods pm_linux_sysfs = { "linux-sysfs", "The sys filesystem on Linux", sysfs_config, sysfs_detect, sysfs_init, sysfs_cleanup, sysfs_scan, sysfs_fill_info, sysfs_read, sysfs_write, sysfs_read_vpd, NULL, /* init_dev */ sysfs_cleanup_dev };