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fix(rapi): size $GI buffers from MCU_ID_LEN, not the target name #56

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fix(rapi): size $GI buffers from MCU_ID_LEN, not the target name #56

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8 changes: 7 additions & 1 deletion firmware/open_evse/open_evse.h
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Original file line number Diff line number Diff line change
Expand Up @@ -527,7 +527,13 @@ extern AutoCurrentCapacityController g_ACCController;
// 10-byte MCU id needs only 33 for $GI, so the LCD-derived 34 still fits;
// keep AVR unchanged so its RAM footprint does not grow. See the matching
// #error guard in rapi_proc.cpp.
#ifdef TARGET_SAMD
//
// Select from the MCU id length rather than the target name: take the
// LCD-derived size unless the $GI reply needs more. Values are unchanged
// from when this was keyed on TARGET_SAMD -- a 16-byte id needs 45 and so
// selects 48, a 10-byte id needs 33 and so keeps the LCD-derived 34.
#define TMP_BUF_GI_REPLYLEN (3 + 1 + (2*MCU_ID_LEN) + 4 + 4 + 1)
#if defined(MCU_ID_LEN) && (TMP_BUF_GI_REPLYLEN > ((LCD_MAX_CHARS_PER_LINE+1)*2))
#define TMP_BUF_SIZE 48
#else
#define TMP_BUF_SIZE ((LCD_MAX_CHARS_PER_LINE+1)*2)
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16 changes: 11 additions & 5 deletions firmware/open_evse/rapi_proc.h
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Expand Up @@ -487,11 +487,17 @@ Z0 closems holdpwm

// buffer[] holds an inbound RAPI command and is reused to build the
// outbound response text. The longest response text is $GI (get MCU id),
// whose #else branch writes 2*MCU_ID_LEN hex chars plus a NUL. On SAMD
// MCU_ID_LEN is 16, so that is 2*16+1 = 33 bytes and the historic 32-byte
// buffer overflowed by one, corrupting the adjacent bufCnt member. Size
// per target so AVR RAM cost stays zero.
#ifdef TARGET_SAMD
// whose #else branch writes 2*MCU_ID_LEN hex chars plus a NUL. With a
// 16-byte MCU id that is 2*16+1 = 33 bytes and the historic 32-byte buffer
// overflowed by one, corrupting the adjacent bufCnt member.
//
// Size from the MCU id length rather than the target name, so any target
// inherits the right buffer automatically. The values are unchanged from
// when this was keyed on TARGET_SAMD: a 16-byte id selects 40, a 10-byte
// id selects 32, so AVR RAM cost stays zero (ESRAPI_BUFLEN sizes three
// buffers there -- buffer[], g_rapiSerialBuffer and g_rapiI2ClBuffer).
#define ESRAPI_GI_RESPLEN (2*MCU_ID_LEN + 1)
#if defined(MCU_ID_LEN) && (ESRAPI_GI_RESPLEN > 32)
#define ESRAPI_BUFLEN 40
#else
#define ESRAPI_BUFLEN 32
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