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v3.11.1
lib/sysfs.c
609 строк
15 KB
Martin Mares
Get rid of workarounds for Linux systems without pread/pwrite
29 дек 2023, 17:27
29 дек 2023, 17:27
30e9f21
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/* * The PCI Library -- Configuration Access via /sys/bus/pci * * Copyright (c) 2003 Matthew Wilcox <matthew@wil.cx> * Copyright (c) 1997--2023 Martin Mares <mj@ucw.cz> * * Can be freely distributed and used under the terms of the GNU GPL v2+. * * SPDX-License-Identifier: GPL-2.0-or-later */ #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" 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]; struct { pciaddr_t flags, base_addr, size; } lines[10]; int have_bar_bases, have_rom_base, have_bridge_bases; FILE *file; int i; have_bar_bases = have_rom_base = have_bridge_bases = 0; 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+6+4+1; 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; have_bar_bases = 1; } else if (i == 6) { d->rom_flags = flags; flags &= PCI_ADDR_FLAG_MASK; d->rom_base_addr = start | flags; d->rom_size = size; have_rom_base = 1; } else if (i < 7+6+4) { /* * If kernel was compiled without CONFIG_PCI_IOV option then after * the ROM line for configured bridge device (that which had set * subordinary bus number to non-zero value) are four additional lines * which describe resources behind bridge. For PCI-to-PCI bridges they * are: IO, MEM, PREFMEM and empty. For CardBus bridges they are: IO0, * IO1, MEM0 and MEM1. For unconfigured bridges and other devices * there is no additional line after the ROM line. If kernel was * compiled with CONFIG_PCI_IOV option then after the ROM line and * before the first bridge resource line are six additional lines * which describe IOV resources. Read all remaining lines in resource * file and based on the number of remaining lines (0, 4, 6, 10) parse * resources behind bridge. */ lines[i-7].flags = flags; lines[i-7].base_addr = start; lines[i-7].size = size; } } if (i == 7+4 || i == 7+6+4) { int offset = (i == 7+6+4) ? 6 : 0; for (i = 0; i < 4; i++) { d->bridge_flags[i] = lines[offset+i].flags; d->bridge_base_addr[i] = lines[offset+i].base_addr; d->bridge_size[i] = lines[offset+i].size; } have_bridge_bases = 1; } fclose(file); if (!have_bar_bases) clear_fill(d, PCI_FILL_BASES | PCI_FILL_SIZES | PCI_FILL_IO_FLAGS); if (!have_rom_base) clear_fill(d, PCI_FILL_ROM_BASE); if (!have_bridge_bases) clear_fill(d, PCI_FILL_BRIDGE_BASES); } 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; 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 void sysfs_fill_info(struct pci_dev *d, unsigned int flags) { int value, want_class, want_class_ext; if (!d->access->buscentric) { /* * These fields can be read from the config registers, but we want to show * the kernel's view, which has regions and IRQs remapped and other fields * (most importantly classes) possibly fixed if the device is known broken. */ if (want_fill(d, flags, PCI_FILL_IDENT)) { d->vendor_id = sysfs_get_value(d, "vendor", 1); d->device_id = sysfs_get_value(d, "device", 1); } want_class = want_fill(d, flags, PCI_FILL_CLASS); want_class_ext = want_fill(d, flags, PCI_FILL_CLASS_EXT); if (want_class || want_class_ext) { value = sysfs_get_value(d, "class", 1); if (want_class) d->device_class = value >> 8; if (want_class_ext) { d->prog_if = value & 0xff; value = sysfs_get_value(d, "revision", 0); if (value < 0) value = pci_read_byte(d, PCI_REVISION_ID); if (value >= 0) d->rev_id = value; } } if (want_fill(d, flags, PCI_FILL_SUBSYS)) { value = sysfs_get_value(d, "subsystem_vendor", 0); if (value >= 0) { d->subsys_vendor_id = value; value = sysfs_get_value(d, "subsystem_device", 0); if (value >= 0) d->subsys_id = value; } else clear_fill(d, PCI_FILL_SUBSYS); } if (want_fill(d, flags, PCI_FILL_IRQ)) d->irq = sysfs_get_value(d, "irq", 1); if (want_fill(d, flags, PCI_FILL_BASES | PCI_FILL_ROM_BASE | PCI_FILL_SIZES | PCI_FILL_IO_FLAGS | PCI_FILL_BRIDGE_BASES)) sysfs_get_resources(d); if (want_fill(d, flags, PCI_FILL_PARENT)) { unsigned int domain, bus, dev, func; char *path_abs, *path_canon, *name; char path_rel[OBJNAMELEN]; struct pci_dev *parent; /* Construct sysfs path for parent device */ sysfs_obj_name(d, "..", path_rel); path_abs = realpath(path_rel, NULL); name = path_abs ? strrchr(path_abs, '/') : NULL; name = name ? name+1 : name; parent = NULL; if (name && sscanf(name, "%x:%x:%x.%d", &domain, &bus, &dev, &func) == 4 && domain <= 0x7fffffff) for (parent = d->access->devices; parent; parent = parent->next) if (parent->domain == (int)domain && parent->bus == bus && parent->dev == dev && parent->func == func) break; if (parent) { /* Check if parsed BDF address from parent sysfs device is really expected PCI device */ sysfs_obj_name(parent, ".", path_rel); path_canon = realpath(path_rel, NULL); if (!path_canon || strcmp(path_canon, path_abs) != 0) parent = NULL; if (path_canon) free(path_canon); } if (parent) d->parent = parent; else clear_fill(d, PCI_FILL_PARENT); if (path_abs) free(path_abs); } } if (want_fill(d, flags, 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 (want_fill(d, flags, 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 (want_fill(d, flags, 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 (want_fill(d, flags, PCI_FILL_NUMA_NODE)) d->numa_node = sysfs_get_value(d, "numa_node", 0); if (want_fill(d, flags, PCI_FILL_IOMMU_GROUP)) { char *group_link = sysfs_deref_link(d, "iommu_group"); if (group_link) { pci_set_property(d, PCI_FILL_IOMMU_GROUP, basename(group_link)); free(group_link); } } if (want_fill(d, flags, 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); } } if (want_fill(d, flags, PCI_FILL_DRIVER)) { char *driver_path = sysfs_deref_link(d, "driver"); if (driver_path) { char *driver = strrchr(driver_path, '/'); driver = driver ? driver+1 : driver_path; pci_set_property(d, PCI_FILL_DRIVER, driver); free(driver_path); } else clear_fill(d, PCI_FILL_DRIVER); } 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); } 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 = pread(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 = pwrite(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; } 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; } 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 };