crossystem: Change ReadFileInt to take an unsigned int pointer

Currently ReadFileInt assumes that an integer value read from a file
is never going to be "-1" and uses that value to indicate failure.
In particular for GPIO values that may be returned by the kernel it
is possible for them to be not simply 0 or 1 but instead a bit within
the GPIO status register that indicates the value.

The function semantics are changed to have the caller pass in the
variable to store the integer in, and use the return code explicitly
as a pass or fail condition.

This requires all the callers of ReadFileInt to be changed to use the
new scheme, and the x86 ReadGpio function is changed to normalize the
GPIO value that is read from the kernel instead of assuming it is
always 1 for active high values.

BUG=chrome-os-partner:32645
BRANCH=samus,auron
TEST=build for samus, check crossystem output and ensure that all
values are properly reported and that wpsw_cur is correct now.
Also tested to ensure no changes in output on: x86-alex, daisy,
peach_pit, lumpy, stumpy, nyan_big, nyan_blaze, rush_ryu, panther,
wolf, zako, auron, rambi, squawks, parrot_ivb, veyron_pinky

Change-Id: I824152eed5f96cf1faaa18ba31a01f4d346ad172
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/223009
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

4 files changed, 122 insertions, 92 deletions

diff --git a/host/arch/arm/lib/crossystem_arch.c b/host/arch/arm/lib/crossystem_arch.c
index 92b61b4c..3864451c 100644
--- a/host/arch/arm/lib/crossystem_arch.c
+++ b/host/arch/arm/lib/crossystem_arch.c
@@ -68,12 +68,15 @@ const PlatformFamily platform_family_array[] = {
 
 static int FindEmmcDev(void) {
   int mmcblk;
+  unsigned value;
   char filename[FNAME_SIZE];
   for (mmcblk = 0; mmcblk < MAX_NMMCBLK; mmcblk++) {
     /* Get first non-removable mmc block device */
     snprintf(filename, sizeof(filename), "/sys/block/mmcblk%d/removable",
               mmcblk);
-    if (ReadFileInt(filename) == 0)
+    if (ReadFileInt(filename, &value) < 0)
+      continue;
+    if (value == 0)
       return mmcblk;
   }
   /* eMMC not found */
@@ -211,24 +214,23 @@ static char * ReadFdtPlatformFamily(void) {
 
 static int VbGetPlatformGpioStatus(const char* name) {
   char gpio_name[FNAME_SIZE];
-  int value;
+  unsigned value;
 
   snprintf(gpio_name, sizeof(gpio_name), "%s/%s/value",
            PLATFORM_DEV_PATH, name);
-  value = ReadFileInt(gpio_name);
+  if (ReadFileInt(gpio_name, &value) < 0)
+    return -1;
 
-  return value;
+  return (int)value;
 }
 
 static int VbGetGpioStatus(unsigned gpio_number) {
   char gpio_name[FNAME_SIZE];
-  int value;
+  unsigned value;
 
   snprintf(gpio_name, sizeof(gpio_name), "%s/gpio%d/value",
            GPIO_BASE_PATH, gpio_number);
-  value = ReadFileInt(gpio_name);
-
-  if (value == -1) {
+  if (ReadFileInt(gpio_name, &value) < 0) {
     /* Try exporting the GPIO */
     FILE* f = fopen(GPIO_EXPORT_PATH, "wt");
     if (!f)
@@ -237,10 +239,11 @@ static int VbGetGpioStatus(unsigned gpio_number) {
     fclose(f);
 
     /* Try re-reading the GPIO value */
-    value = ReadFileInt(gpio_name);
+    if (ReadFileInt(gpio_name, &value) < 0)
+      return -1;
   }
 
-  return value;
+  return (int)value;
 }
 
 static int VbGetVarGpio(const char* name) {
diff --git a/host/arch/x86/lib/crossystem_arch.c b/host/arch/x86/lib/crossystem_arch.c
index e6690512..eb87f84d 100644
--- a/host/arch/x86/lib/crossystem_arch.c
+++ b/host/arch/x86/lib/crossystem_arch.c
@@ -120,7 +120,7 @@ static void VbFixCmosChecksum(FILE* file) {
 }
 
 
-static int VbCmosRead(int offs, size_t size, void *ptr) {
+static int VbCmosRead(unsigned offs, size_t size, void *ptr) {
   size_t res;
   FILE* f;
 
@@ -144,7 +144,7 @@ static int VbCmosRead(int offs, size_t size, void *ptr) {
 }
 
 
-static int VbCmosWrite(int offs, size_t size, const void *ptr) {
+static int VbCmosWrite(unsigned offs, size_t size, const void *ptr) {
   size_t res;
   FILE* f;
 
@@ -169,13 +169,14 @@ static int VbCmosWrite(int offs, size_t size, const void *ptr) {
 
 
 int VbReadNvStorage(VbNvContext* vnc) {
-  int offs;
+  unsigned offs, blksz;
 
   /* Get the byte offset from VBNV */
-  offs = ReadFileInt(ACPI_VBNV_PATH ".0");
-  if (offs == -1)
+  if (ReadFileInt(ACPI_VBNV_PATH ".0", &offs) < 0)
     return -1;
-  if (VBNV_BLOCK_SIZE > ReadFileInt(ACPI_VBNV_PATH ".1"))
+  if (ReadFileInt(ACPI_VBNV_PATH ".1", &blksz) < 0)
+    return -1;
+  if (VBNV_BLOCK_SIZE > blksz)
     return -1;  /* NV storage block is too small */
 
   if (0 != VbCmosRead(offs, VBNV_BLOCK_SIZE, vnc->raw))
@@ -186,16 +187,17 @@ int VbReadNvStorage(VbNvContext* vnc) {
 
 
 int VbWriteNvStorage(VbNvContext* vnc) {
-  int offs;
+  unsigned offs, blksz;
 
   if (!vnc->raw_changed)
     return 0;  /* Nothing changed, so no need to write */
 
   /* Get the byte offset from VBNV */
-  offs = ReadFileInt(ACPI_VBNV_PATH ".0");
-  if (offs == -1)
+  if (ReadFileInt(ACPI_VBNV_PATH ".0", &offs) < 0)
+    return -1;
+  if (ReadFileInt(ACPI_VBNV_PATH ".1", &blksz) < 0)
     return -1;
-  if (VBNV_BLOCK_SIZE > ReadFileInt(ACPI_VBNV_PATH ".1"))
+  if (VBNV_BLOCK_SIZE > blksz)
     return -1;  /* NV storage block is too small */
 
   if (0 != VbCmosWrite(offs, VBNV_BLOCK_SIZE, vnc->raw))
@@ -337,12 +339,11 @@ VbSharedDataHeader* VbSharedDataRead(void) {
  *
  * Returns 0 if the mask is clear in the field, 1 if set, or -1 if error. */
 static int VbGetCmosRebootField(uint8_t mask) {
-  int chnv;
+  unsigned chnv;
   uint8_t nvbyte;
 
   /* Get the byte offset from CHNV */
-  chnv = ReadFileInt(ACPI_CHNV_PATH);
-  if (chnv == -1)
+  if (ReadFileInt(ACPI_CHNV_PATH, &chnv) < 0)
     return -1;
 
   if (0 != VbCmosRead(chnv, 1, &nvbyte))
@@ -358,12 +359,11 @@ static int VbGetCmosRebootField(uint8_t mask) {
  *
  * Returns 0 if success, or -1 if error. */
 static int VbSetCmosRebootField(uint8_t mask, int value) {
-  int chnv;
+  unsigned chnv;
   uint8_t nvbyte;
 
   /* Get the byte offset from CHNV */
-  chnv = ReadFileInt(ACPI_CHNV_PATH);
-  if (chnv == -1)
+  if (ReadFileInt(ACPI_CHNV_PATH, &chnv) < 0)
     return -1;
 
   if (0 != VbCmosRead(chnv, 1, &nvbyte))
@@ -388,27 +388,31 @@ static int VbSetCmosRebootField(uint8_t mask, int value) {
  * Passed the destination and its size.  Returns the destination, or
  * NULL if error. */
 static const char* VbReadMainFwType(char* dest, int size) {
+  unsigned value;
 
   /* Try reading type from BINF.3 */
-  switch(ReadFileInt(ACPI_BINF_PATH ".3")) {
-    case BINF3_NETBOOT:
-      return StrCopy(dest, "netboot", size);
-    case BINF3_RECOVERY:
-      return StrCopy(dest, "recovery", size);
-    case BINF3_NORMAL:
-      return StrCopy(dest, "normal", size);
-    case BINF3_DEVELOPER:
-      return StrCopy(dest, "developer", size);
-    default:
-      break;  /* Fall through to legacy handling */
+  if (ReadFileInt(ACPI_BINF_PATH ".3", &value) == 0) {
+    switch(value) {
+      case BINF3_NETBOOT:
+        return StrCopy(dest, "netboot", size);
+      case BINF3_RECOVERY:
+        return StrCopy(dest, "recovery", size);
+      case BINF3_NORMAL:
+        return StrCopy(dest, "normal", size);
+      case BINF3_DEVELOPER:
+        return StrCopy(dest, "developer", size);
+      default:
+        break;  /* Fall through to legacy handling */
+    }
   }
 
   /* Fall back to BINF.0 for legacy systems like Mario. */
-  switch(ReadFileInt(ACPI_BINF_PATH ".0")) {
-    case -1:
-      /* Both BINF.0 and BINF.3 are missing, so this isn't Chrome OS
-       * firmware. */
-      return StrCopy(dest, "nonchrome", size);
+  if (ReadFileInt(ACPI_BINF_PATH ".0", &value) < 0)
+    /* Both BINF.0 and BINF.3 are missing, so this isn't Chrome OS
+     * firmware. */
+    return StrCopy(dest, "nonchrome", size);
+
+  switch(value) {
     case BINF0_NORMAL:
       return StrCopy(dest, "normal", size);
     case BINF0_DEVELOPER:
@@ -431,15 +435,16 @@ static const char* VbReadMainFwType(char* dest, int size) {
 
 /* Read the recovery reason.  Returns the reason code or -1 if error. */
 static int VbGetRecoveryReason(void) {
-  int value = -1;
+  unsigned value;
 
   /* Try reading type from BINF.4 */
-  value = ReadFileInt(ACPI_BINF_PATH ".4");
-  if (-1 != value)
+  if (ReadFileInt(ACPI_BINF_PATH ".4", &value) == 0)
     return value;
 
   /* Fall back to BINF.0 for legacy systems like Mario. */
-  switch(ReadFileInt(ACPI_BINF_PATH ".0")) {
+  if (ReadFileInt(ACPI_BINF_PATH ".0", &value) < 0)
+    return -1;
+  switch(value) {
     case BINF0_NORMAL:
     case BINF0_DEVELOPER:
       return VBNV_RECOVERY_NOT_REQUESTED;
@@ -500,7 +505,7 @@ static char* ReadPlatformFamilyString(char* dest, int size) {
  * we look for a directory named /sys/class/gpio/gpiochip<O>/. If there's not
  * exactly one match for that, we're SOL.
  */
-static int FindGpioChipOffset(int *gpio_num, int *offset) {
+static int FindGpioChipOffset(unsigned *gpio_num, unsigned *offset) {
   DIR *dir;
   struct dirent *ent;
   int match = 0;
@@ -511,7 +516,7 @@ static int FindGpioChipOffset(int *gpio_num, int *offset) {
   }
 
   while(0 != (ent = readdir(dir))) {
-    if (1 == sscanf(ent->d_name, "gpiochip%d", offset)) {
+    if (1 == sscanf(ent->d_name, "gpiochip%u", offset)) {
       match++;
     }
   }
@@ -530,10 +535,10 @@ static int FindGpioChipOffset(int *gpio_num, int *offset) {
  *   2  | 0x1000
  *   3  | 0x2000
  */
-static int BayTrailFindGpioChipOffset(int *gpio_num, int *offset) {
+static int BayTrailFindGpioChipOffset(unsigned *gpio_num, unsigned *offset) {
   DIR *dir;
   struct dirent *ent;
-  int expected_uid;
+  unsigned expected_uid;
   int match = 0;
 
   /* Obtain relative GPIO number. */
@@ -557,12 +562,15 @@ static int BayTrailFindGpioChipOffset(int *gpio_num, int *offset) {
 
   while(0 != (ent = readdir(dir))) {
     /* For every gpiochip entry determine uid. */
-    if (1 == sscanf(ent->d_name, "gpiochip%d", offset)) {
+    if (1 == sscanf(ent->d_name, "gpiochip%u", offset)) {
       char uid_file[128];
+      unsigned uid_value;
       snprintf(uid_file, sizeof(uid_file),
-               "%s/gpiochip%d/device/firmware_node/uid", GPIO_BASE_PATH,
+               "%s/gpiochip%u/device/firmware_node/uid", GPIO_BASE_PATH,
                *offset);
-      if (expected_uid == ReadFileInt(uid_file)) {
+      if (ReadFileInt(uid_file, &uid_value) < 0)
+        continue;
+      if (expected_uid == uid_value) {
         match++;
         break;
       }
@@ -576,7 +584,7 @@ static int BayTrailFindGpioChipOffset(int *gpio_num, int *offset) {
 
 struct GpioChipset {
   const char *name;
-  int (*ChipOffsetAndGpioNumber)(int *gpio_num, int *chip_offset);
+  int (*ChipOffsetAndGpioNumber)(unsigned *gpio_num, unsigned *chip_offset);
 };
 
 static const struct GpioChipset chipsets_supported[] = {
@@ -603,34 +611,36 @@ static const struct GpioChipset *FindChipset(const char *name) {
 /* Read a GPIO of the specified signal type (see ACPI GPIO SignalType).
  *
  * Returns 1 if the signal is asserted, 0 if not asserted, or -1 if error. */
-static int ReadGpio(int signal_type) {
+static int ReadGpio(unsigned signal_type) {
   char name[128];
   int index = 0;
-  int gpio_type;
-  int active_high;
-  int controller_num;
-  int controller_offset = 0;
+  unsigned gpio_type;
+  unsigned active_high;
+  unsigned controller_num;
+  unsigned controller_offset = 0;
   char controller_name[128];
-  int value;
+  unsigned value;
   const struct GpioChipset *chipset;
 
   /* Scan GPIO.* to find a matching signal type */
   for (index = 0; ; index++) {
     snprintf(name, sizeof(name), "%s.%d/GPIO.0", ACPI_GPIO_PATH, index);
-    gpio_type = ReadFileInt(name);
+    if (ReadFileInt(name, &gpio_type) < 0)
+      return -1;                  /* Ran out of GPIOs before finding a match */
     if (gpio_type == signal_type)
       break;
-    else if (gpio_type == -1)
-      return -1;                  /* Ran out of GPIOs before finding a match */
   }
 
   /* Read attributes and controller info for the GPIO */
   snprintf(name, sizeof(name), "%s.%d/GPIO.1", ACPI_GPIO_PATH, index);
-  active_high = ReadFileBit(name, 0x00000001);
+  if (ReadFileInt(name, &active_high) < 0)
+    return -1;
   snprintf(name, sizeof(name), "%s.%d/GPIO.2", ACPI_GPIO_PATH, index);
-  controller_num = ReadFileInt(name);
-  if (active_high == -1 || controller_num == -1)
-    return -1;                          /* Missing needed info */
+  if (ReadFileInt(name, &controller_num) < 0)
+    return -1;
+  /* Do not attempt to read GPIO that is set to -1 in ACPI */
+  if (controller_num == 0xFFFFFFFF)
+    return -1;
 
   /* Check for chipsets we recognize. */
   snprintf(name, sizeof(name), "%s.%d/GPIO.3", ACPI_GPIO_PATH, index);
@@ -648,22 +658,21 @@ static int ReadGpio(int signal_type) {
   /* Try reading the GPIO value */
   snprintf(name, sizeof(name), "%s/gpio%d/value",
            GPIO_BASE_PATH, controller_offset);
-  value = ReadFileInt(name);
-
-  if (value == -1) {
+  if (ReadFileInt(name, &value) < 0) {
     /* Try exporting the GPIO */
     FILE* f = fopen(GPIO_EXPORT_PATH, "wt");
     if (!f)
       return -1;
-    fprintf(f, "%d", controller_offset);
+    fprintf(f, "%u", controller_offset);
     fclose(f);
 
     /* Try re-reading the GPIO value */
-    value = ReadFileInt(name);
+    if (ReadFileInt(name, &value) < 0)
+      return -1;
   }
 
-  if (value == -1)
-    return -1;
+  /* Normalize the value read from the kernel in case it is not always 1. */
+  value = value ? 1 : 0;
 
   /* Compare the GPIO value with the active value and return 1 if match. */
   return (value == active_high ? 1 : 0);
@@ -674,8 +683,13 @@ int VbGetArchPropertyInt(const char* name) {
   int value = -1;
 
   /* Values from ACPI */
-  if (!strcasecmp(name,"fmap_base"))
-    value = ReadFileInt(ACPI_FMAP_PATH);
+  if (!strcasecmp(name,"fmap_base")) {
+    unsigned fmap_base;
+    if (ReadFileInt(ACPI_FMAP_PATH, &fmap_base) < 0)
+      return -1;
+    else
+      value = (int)fmap_base;
+  }
 
   /* Switch positions */
   if (!strcasecmp(name,"devsw_cur")) {
@@ -713,9 +727,17 @@ int VbGetArchPropertyInt(const char* name) {
   /* Saved memory is at a fixed location for all H2C BIOS.  If the CHSW
    * path exists in sysfs, it's a H2C BIOS. */
   if (!strcasecmp(name,"savedmem_base")) {
-    return (-1 == ReadFileInt(ACPI_CHSW_PATH) ? -1 : 0x00F00000);
+    unsigned savedmem_base;
+    if (ReadFileInt(ACPI_CHSW_PATH, &savedmem_base) < 0)
+      return -1;
+    else
+      return 0x00F00000;
   } else if (!strcasecmp(name,"savedmem_size")) {
-    return (-1 == ReadFileInt(ACPI_CHSW_PATH) ? -1 : 0x00100000);
+    unsigned savedmem_size;
+    if (ReadFileInt(ACPI_CHSW_PATH, &savedmem_size) < 0)
+      return -1;
+    else
+      return 0x00100000;
   }
 
   /* NV storage values.  If unable to get from NV storage, fall back to the
@@ -738,14 +760,15 @@ int VbGetArchPropertyInt(const char* name) {
    * older systems where it's not, it was stored in a file in the
    * stateful partition. */
   if (!strcasecmp(name,"fwupdate_tries")) {
+    unsigned fwupdate_value;
     if (-1 != VbGetNvStorage(VBNV_KERNEL_FIELD))
       return -1;  /* NvStorage supported; fail through arch-specific
                    * implementation to normal implementation. */
-
     /* Read value from file; missing file means value=0. */
-    value = ReadFileInt(NEED_FWUPDATE_PATH);
-    if (-1 == value)
+    if (ReadFileInt(NEED_FWUPDATE_PATH, &fwupdate_value) < 0)
       value = 0;
+    else
+      value = (int)fwupdate_value;
   }
 
   return value;
@@ -754,6 +777,7 @@ int VbGetArchPropertyInt(const char* name) {
 
 const char* VbGetArchPropertyString(const char* name, char* dest,
                                     size_t size) {
+  unsigned value;
 
   if (!strcasecmp(name,"arch")) {
     return StrCopy(dest, "x86", size);
@@ -764,7 +788,9 @@ const char* VbGetArchPropertyString(const char* name, char* dest,
   } else if (!strcasecmp(name,"ro_fwid")) {
     return ReadFileString(dest, size, ACPI_BASE_PATH "/FRID");
   } else if (!strcasecmp(name,"mainfw_act")) {
-    switch(ReadFileInt(ACPI_BINF_PATH ".1")) {
+    if (ReadFileInt(ACPI_BINF_PATH ".1", &value) < 0)
+      return NULL;
+    switch(value) {
       case 0:
         return StrCopy(dest, "recovery", size);
       case 1:
@@ -777,7 +803,9 @@ const char* VbGetArchPropertyString(const char* name, char* dest,
   } else if (!strcasecmp(name,"mainfw_type")) {
     return VbReadMainFwType(dest, size);
   } else if (!strcasecmp(name,"ecfw_act")) {
-    switch(ReadFileInt(ACPI_BINF_PATH ".2")) {
+    if (ReadFileInt(ACPI_BINF_PATH ".2", &value) < 0)
+      return NULL;
+    switch(value) {
       case 0:
         return StrCopy(dest, "RO", size);
       case 1:
diff --git a/host/lib/host_misc.c b/host/lib/host_misc.c
index 110feee0..adc39420 100644
--- a/host/lib/host_misc.c
+++ b/host/lib/host_misc.c
@@ -73,26 +73,25 @@ char* ReadFileString(char* dest, int size, const char* filename) {
 }
 
 
-int ReadFileInt(const char* filename) {
+int ReadFileInt(const char* filename, unsigned* value) {
   char buf[64];
-  int value;
   char* e = NULL;
 
   if (!ReadFileString(buf, sizeof(buf), filename))
     return -1;
 
   /* Convert to integer.  Allow characters after the int ("123 blah"). */
-  value = strtol(buf, &e, 0);
+  *value = (unsigned)strtoul(buf, &e, 0);
   if (e == buf)
     return -1;  /* No characters consumed, so conversion failed */
 
-  return value;
+  return 0;
 }
 
 
 int ReadFileBit(const char* filename, int bitmask) {
-  int value = ReadFileInt(filename);
-  if (value == -1)
+  unsigned value;
+  if (ReadFileInt(filename, &value) < 0)
     return -1;
   else return (value & bitmask ? 1 : 0);
 }
diff --git a/host/lib/include/host_misc.h b/host/lib/include/host_misc.h
index 9bfa721d..b2b4fb94 100644
--- a/host/lib/include/host_misc.h
+++ b/host/lib/include/host_misc.h
@@ -28,10 +28,10 @@ uint8_t* ReadFile(const char* filename, uint64_t* size);
  * Returns the destination, or NULL if error. */
 char* ReadFileString(char* dest, int size, const char* filename);
 
-/* Read an integer from a file.
+/* Read an unsigned integer from a file and save into passed pointer.
  *
- * Returns the parsed integer, or -1 if error. */
-int ReadFileInt(const char* filename);
+ * Returns 0 if success, -1 if error. */
+int ReadFileInt(const char* filename, unsigned* value);
 
 /* Check if a bit is set in a file which contains an integer.
  *